IPAC2011 - List of Keywords (linac)

Paper	Title	Other Keywords	Page
MOXAA01	ALBA Synchrotron Light Source Commissioning	storage-ring, booster, synchrotron, injection	1
	D. Einfeld CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain
	ALBA is a 3rd generation Synchrotron Light Source build in Barcelona, Spain. It is a 3 GeV Light Source with a circumference of roughly 270 m, an emittance of 4.4 nmrad and a design current of 400 mA. The storage ring has 24 straight sections from which 19 can be used for the installation of insertion devices, the rest will be used for injection, RF-cavities and diagnostic. The storage ring has been optimized for a high photon flux density for the users. The 3 GeV booster synchrotron with an emittance smaller the 10 nmrad is installed in the same tunnel. The pre injector is a 100 MeV Linac. The project started officially in 2004. The linac is operating since 2008, the booster since 2010 and the first commissioning phase for the storage ring will be finished in June 2011. This presentation gives an overview of the ALBA project with the emphasis on the results of the commissioning of the three accelerators Linac, booster synchrotron and storage ring.
	Slides MOXAA01 [8.891 MB]

MOXBA01	J-PARC Beam Commissioning Progress	beam-losses, injection, extraction, vacuum	6
	H. Hotchi JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	The J-PARC is a multi-purpose proton accelerator facility amiming at MW-class output beam power, consisting of a 400 MeV H⁻ linac, a 3-GeV RCS, a 50-GeV MR (Main Ring) and three experimental facilities, the MLF (materials and life science experimental facility), the HD (hadron experimental hall) and the NU (neutrino beam line). The J-PARC beam commissioning started in November 2006 from the linac to the downstream facilities. The current output beam power from the RCS to the MLF users is 210 kW, and the MR delivers 145 kW beam to the NU by fast extraction and a few kW beam to the HD by slow extraction. In this talk, we present a current status of the J-PARC beam commissioning, in which a recent progress in the course of the RCS beam power ramp-up scenario will be described in more detail. This talk will focus on the issues (including beam dynamics), challenges, solutions, and lessons learned during the commissioning and user operation of J-PARC and future plans.
	Slides MOXBA01 [2.615 MB]

MOYBA01	Present Status of the ILC Project and Developments	cavity, linear-collider, collider, electron	16
	M.C. Ross Fermilab, Batavia, USA N.J. Walker DESY, Hamburg, Germany A. Yamamoto KEK, Ibaraki, Japan
	Funding: FNAL is operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy. The Technical Design of the ILC Project will be finished in late 2012. The Technical Design Report will include a description of the updated design, with a cost estimate and a project plan, and the results of R & D done in support of the ILC. Results from directed ILC R & D are used to reduce the cost and risk associated with the ILC design. We present a summary of key challenges and show how the global R & D effort has addressed them. The most important activity has been in pursuit of very high gradient superconducting RF linac technology. There has been excellent progress toward the goal of practical industrial production of niobium sheet-metal cavities with gradient performance in excess of 35 MV/m. In addition, three purpose-built beam test facilities have been constructed and used to study and demonstrate high current linac performance, electron-cloud beam dynamics and precision beam control. The report also includes a summary of component design studies and conventional facilities cost optimization design studies.
	Slides MOYBA01 [9.755 MB]

MOOCA02	Two Beam Test Stand Experiments in the CTF3 Facility	accelerating-gradient, acceleration, diagnostics, ion	29
	W. Farabolini, F. Peauger CEA/DSM/IRFU, France J. Barranco, S. Bettoni, B. Constance, R. Corsini, M. Csatari, S. Döbert, A. Dubrovskiy, C. Heßler, T. Persson, G. Riddone, P.K. Skowroński, F. Tecker CERN, Geneva, Switzerland D. Gudkov, A. Solodko JINR, Dubna, Moscow Region, Russia M. Jacewicz, T. Muranaka, A. Palaia, R.J.M.Y. Ruber, V.G. Ziemann Uppsala University, Uppsala, Sweden
	The CLEX building in the CTF3 facility is the place where essential experiments are performed to validate the Two-Beam Acceleration scheme upon which the CLIC project relies. The Drive Beam enters the CLEX after being recombined in the Delay loop and the Combiner Ring in intense beam trains of 24 A – 150 MeV lasting 140 ns and bunched at 12 GHz, although other beam parameters are also accessible. This beam is then decelerated in dedicated structures installed in the Test Beam Line (TBL) and in the Two-Beam Test Stand (TBTS) aimed at delivering bursts of 12 GHz RF power. In the TBTS this power is used to generate a high accelerating gradient of 100 MV/m in specially designed accelerating structures. To assess the performances of these structures a probe beam is used, produced by a small Linac. We reported here the various experiences conducted in the TBTS making use of the versatility the probe beam and of dedicated diagnostics.
	Slides MOOCA02 [3.003 MB]

MOODA02	S1-Global Module Tests at STF/KEK	cavity, cryomodule, SRF, feedback	38
	D. Kostin, K. Jensch, L. Lilje, A. Matheisen, W.-D. Möller, P. Schilling, M. Schmökel, N.J. Walker, H. Weise DESY, Hamburg, Germany C. Adolphsen, C.D. Nantista SLAC, Menlo Park, California, USA M. Akemoto, S. Fukuda, K. Hara, H. Hayano, N. Higashi, E. Kako, H. Katagiri, Y. Kojima, Y. Kondo, T. Matsumoto, H. Matsushita, S. Michizono, T. Miura, H. Nakai, H. Nakajima, K. Nakanishi, S. Noguchi, N. Ohuchi, T. Saeki, M. Satoh, T. Shidara, T. Shishido, T. Takenaka, A. Terashima, N. Toge, K. Tsuchiya, K. Watanabe, S. Yamaguchi, A. Yamamoto, Y. Yamamoto, K. Yokoya KEK, Ibaraki, Japan T.T. Arkan, S. Barbanotti, M.A. Battistoni, H. Carter, M.S. Champion, A. Hocker, R.D. Kephart, J.S. Kerby, D.V. Mitchell, T.J. Peterson, Y.M. Pischalnikov, M.C. Ross, W. Schappert, B.E. Smith Fermilab, Batavia, USA A. Bosotti, C. Pagani, R. Paparella, P. Pierini INFN/LASA, Segrate (MI), Italy
	S1-Global collaborative effort of INFN, DESY, FNAL, SLAC and KEK, recently successfully finished at KEK as a part of ILC GDE, is an important milestone for the ILC. International collaboration of three regions, Asia, North America and Europe, proved to be efficient on the construction and cold tests of the accelerating module consisting of 8 SRF cavities; 2 from FNAL, 2 from DESY and 4 from KEK. Three different cavity tuning systems were tested together with two types of high power couplers. The module was cooled down three times which enabled extensive high power tests with cavities, performance limits investigation, Lorentz force detuning tests, simultaneous multiple cavities operation and other activities such as an operation test of distributed RF scheme with low level RF feedback. The results of this S1-Global module test are presented and discussed.
	Slides MOODA02 [2.982 MB]

MOODA03	First Characterization of a Fully Superconducting RF Photoinjector Cavity	cavity, cathode, laser, solenoid	41
	A. Neumann, W. Anders, R. Barday, A. Jankowiak, T. Kamps, J. Knobloch, O. Kugeler, A.N. Matveenko, T. Quast, J. Rudolph, S.G. Schubert, J. Völker HZB, Berlin, Germany P. Kneisel JLAB, Newport News, Virginia, USA R. Nietubyc The Andrzej Soltan Institute for Nuclear Studies, Centre Swierk, Swierk/Otwock, Poland J.K. Sekutowicz DESY, Hamburg, Germany J. Smedley BNL, Upton, Long Island, New York, USA V. Volkov BINP SB RAS, Novosibirsk, Russia G. Weinberg FHI, Berlin, Germany I. Will MBI, Berlin, Germany
	As a first step towards a high brightness, high average current electron source for the BERLinPro ERL a fully superconducting photo-injector was developed by HZB in collaboration with JLab, DESY and the A. Soltan Institute. This cavity-injector ensemble is made up of a 1.6-cell superconducting cavity with a superconducting lead cathode deposited on the half-cell backwall. A superconducting solenoid is used for emittance compensation. This system, including a diagnostics beamline, has been installed in the HoBiCaT facility to serve as a testbed for beam dynamics studies and to test the combination SRF cavity and superconducting solenoid. This paper summarizes the characterization of the cavity in this configuration including Q measurements, dark current tests and field-stability analyses.
	Slides MOODA03 [10.343 MB]

MOOCB01	Study on the Realignment Plan for J-PARC Linac after the Tohoku Earthquake in Japan	DTL, alignment, simulation, quadrupole	44
	M. Ikegami KEK, Ibaraki, Japan T. Morishita JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	A 9.0-magnitude earthquake struck eastern Japan on March 11, 2011, and it gave rise to damages to the buildings of the J-PARC facilities. In particular, the earthquake caused a deformation of the J-PARC linac tunnel resulting an alignment error of several tens of millimeters in both horizontal and vertical directions. It also caused a change in the relative position between the linac and other facilities of J-PARC complex. To restore the beam operation, we should establish a reasonable realignment plan for J-PARC linac taking various constraints into account and possibly tolerating some residual misalignment. In this paper, we show a study on the realignment plan for J-PARC linac including evaluation of the effect of residual misalignment with particle simulations.
	Slides MOOCB01 [2.659 MB]

MOOCB03	A Novel Method for Quasi-non-interceptive Beam Profile Measurement in a Linac	coupling, diagnostics, emittance, beam-transport	50
	A.V. Aleksandrov ORNL, Oak Ridge, Tennessee, USA
	Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. Beam profile diagnostics is an important tool for understanding beam dynamics in accelerators. Non-interceptive diagnostics have many great advantages but often are difficult in implementation. We suggest a method of measuring beam profiles that is not truly non-interceptive, because beam has to be intercepted at some point, preferably in the beginning of the linac. But significant difference from a conventional interceptive measurement is that beam is not intercepted at any of the points of measurement along the linac. One important application is measuring beam profiles within cryostats of a super-conducting linac. The equipment required for implementing this diagnostic is simple: a set of slits in the beginning of the accelerator, and a Beam Position Monitor (BPM) in the point of measurement. Beam profiles can be measured simultaneously at every BPM along the linac. In this paper we will discuss details of the method, its limitations, and effect of non-linearity, coupling and space charge. Results of a demonstration experiment at SNS will be presented and discussed.
	Slides MOOCB03 [3.365 MB]

MOODB01	Dynamics of the IFMIF Very High-intensity Beam	rfq, emittance, space-charge, cryomodule	53
	P.A.P. Nghiem, R.D. Duperrier, A. Mosnier, D. Uriot CEA/DSM/IRFU, France N. Chauvin, O. Delferrière, W. Simeoni CEA/IRFU, Gif-sur-Yvette, France M. Comunian INFN/LNL, Legnaro (PD), Italy C. Oliver CIEMAT, Madrid, Spain
	For the purpose of material studies for future nuclear fusion reactors, the IFMIF deuteron beams present a simultaneous combination of unprecedentedly high intensity (2x125 mA CW), power (2x5 MW) and space charge. Special considerations and new concepts have been developed in order to overcome these challenges. The global strategy for beam dynamics design in the 40 MeV IFMIF accelerators is presented, stressing on the control of micro-losses, and the possibility of on-line fine tuning. The obtained results are then analysed in terms of beam halo and emittance growth.
	Slides MOODB01 [3.807 MB]

MOODB02	RF Modeling Plans for the European Spallation Source	cavity, HOM, electron, beam-losses	56
	S. Molloy, M. Lindroos, S. Peggs ESS, Lund, Sweden R. Ainsworth Royal Holloway, University of London, Surrey, United Kingdom R.J.M.Y. Ruber Uppsala University, Uppsala, Sweden
	The European Spallation Source (ESS) will be the world's most powerful next generation neutron source. The ESS linac is designed to accelerate highly charged bunches of protons to a final energy of 2.5 GeV, with a design beam power of 5 MW, for collision with a target used to produce the high neutron flux. In order to achieve this several stages of RF acceleration are required, each using a different technology. The high beam current and power require a high degree of control of the accelerating RF, and the specification that no more than 1 W/m of losses will be experienced means that the excitation and decay of the HOMs must be very well understood. Experience at other high power machines also implies that an understanding of the generation and subsequent trajectories of any field-emitted electrons should be understood. Thermal detuning of the HOM couplers due to multipacting is a serious concern here. This paper will outline the RF modeling plans - including the construction of mathematical models, simulations of HOMs, and multipacting - during the current Accelerator Design Update phase, and will discuss several of the more important issues for ESS.
	Slides MOODB02 [48.641 MB]

MOPC001	Linac Waveguide Upgrade at the Australian Synchrotron Light Source	klystron, booster, controls, synchrotron	62
	R.T. Dowd, G. LeBlanc, K. Zingre ASCo, Clayton, Victoria, Australia
	The Australian Synchrotron Light Source (ASLS) uses a 100 MeV linac as the start of the acceleration chain for the injector. The two main accelerating structures of linac are normally fed by independent pulsed klystrons. A recent upgrade to the waveguide system has allowed for a single klystron to power both accelerating structures. While this operation mode delivers a reduced total beam energy, the operation of only a single klystron results in less wear and enhanced robustness against klystron breakdown. Commissioning results of single klystron operation of the linac are shown and future benefits are detailed.

MOPC002	Flow Induced Vibrations of the CLIC X-band Accelerating Structures	quadrupole, alignment, synchrotron, resonance	65
	T.K. Charles, K. Ryan Monash University, Melbourne, Australia M.J. Boland ASCo, Clayton, Victoria, Australia G. Riddone CERN, Geneva, Switzerland A. Samoshkin JINR, Dubna, Moscow Region, Russia
	Turbulent cooling water in the Compact Linear Collider (CLIC) accelerating structures will inevitably induce some vibrations. The maximum acceptable amplitude of vibrations is small, as vibrations in the accelerating structure could lead to beam jitter and alignment difficulties. A Finite Element Analysis model is needed to identify the conditions under which turbulent instabilities and significant vibrations are induced. Due to the orders of magnitude difference between the fluid motion and the structure's motion, small vibrations of the structure will not contribute to the turbulence of the cooling fluid. Therefore the resonant conditions of the cooling channels presented in this paper, directly identify the natural frequencies of the accelerating structures to be avoided under normal operating conditions. In this paper a 2D model of the cooling channel is presented finding spots of turbulence being formed from a shear layer instability. This effect is observed through direct visualisation and wavelet analysis.

MOPC009	Design of a Pi/2 Mode S-Band Low Energy TW Electron Linear Accelerator	electron, coupling, acceleration, simulation	80
	H. Shaker IPM, Tehran, Iran F. Ghasemi sbu, Tehran, Iran H. Shaker CERN, Geneva, Switzerland
	This design is related to a Pi/2 mode S-Band low energy TW electron linear accelerator which is in the construction stage. This project is supported by the school of particles and accelerators, institute for research in fundamental sciences (IPM), Tehran, Iran. This design consists of a buncher and an accelerating structure that are joined and two couplers for the input/output feedings. At each design stage, different methods (analytical or numerical) are used to confirm the results and also to have a better understanding.

MOPC010	Phase-Modulation SLED Operation Mode at Elettra	cavity, LLRF, klystron, target	83
	C. Serpico, P. Delgiusto, A. Fabris, F. Gelmetti, M.M. Milloch, A. Salom, D. Wang ELETTRA, Basovizza, Italy
	FERMI@Elettra is the soft X-ray, fourth generation light source facility at the Elettra Laboratory in Trieste, Italy. It is based on a seeded FEL, driven by a normal conducting linac that is presently expected to operate at 1.5 GeV. The last seven backward traveling wave structures have been equipped with a SLED system. Due to breakdown problems inside the sections, that was the result of high peak fields generated during conventional SLED operation, the sections experienced difficulties in reaching the desired gradients. To lower the peak field and make the compressed pulse “flatter”, phase-modulation of the SLED drive power will be implemented. A description of the phase modulation of the drive power and the results achieved will be reported in the following paper.

MOPC015	S-band Vacuum Isolator and Circulator for Injector System of SPring-8 Linac	vacuum, cavity, insertion, injection	95
	T. Taniuchi, H. Hanaki, S. Suzuki JASRI/SPring-8, Hyogo-ken, Japan A. Miura, K. Shinohara, S. Tsuruoka Nihon Koshuha Co. Ltd, Yokohama, Japan
	A pressurized sulfur hexafluoride (SF6) waveguide system at an injector section of SPring-8 linac, will be replaced with a vacuum waveguide system in order to renew aged equipments and improve a phase stability. For this renewal, RF isolator and a circulator operated in vacuum, are newly developed. High power RF test for these components were performed and a good result for RF and vacuum characteristics were obtained.

MOPC017	Thermal Analyses of an RF Input Coupler for the IFMIF/EVEDA RFQ Linac	rfq, cavity, coupling, beam-transport	101
	S. Maebara JAEA, Ibaraki-ken, Japan
	In the design of prototype RFQ linac for the IFMIF/EVEDA Project, a coupled cavity type of RFQ, which has a longitudinal length of 9.78m, was proposed to accelerate deuteron beam up to 5MeV. The operation frequency of 175MHz was selected to accelerate a large current of 125mA in CW mode. The driving RF power of 1.28 MW by 8 RF input couplers has to be injected to the RFQ cavity. As the RF input coupler design, RF losses including a loop antenna and an RF vacuum window, based on a 6 1/8 inch co-axial waveguide were calculated. In this conference, these results and thermal analysis results in CW operation mode will be presented in details.

MOPC020	Development of an S-band Multi-cell Accelerating Cavity for RF Gun and Booster Linac	gun, cavity, booster, electron	110
	T. Aoki, K. Sakaue, M. Washio RISE, Tokyo, Japan A. Deshpande SAMEER, Mumbai, India M.K. Fukuda, N.K. Kudo, T. Takatomi, N. Terunuma, J. Urakawa KEK, Ibaraki, Japan
	Funding: Work supported by JST Quantum Beam Program We have been developing a photocathode rf gun. The rf gun with multi cell can produce a high energy electron beam, so it may be used for numerous applications such as medicine and industry. At Laser Undulator Compact X-ray source (LUCX), we have developed a compact X-ray source based on inverse Compton scattering. Using a multi cell rf gun will make possible for the X-ray source to use for such applications. S-band 3.5 cell rf electron gun which is 20 cm long can produce more than 10 MeV electron beam. According to the simulation, it is said that the emittance of 3.5 cell rf gun is as low as that of 1.6 cell rf gun. The electromagnetic design has been performed with the code SuperFish, and the particle tracing by Parmela. The new rf gun is already installed and produced a high quality electron beam with energy of more than 10 MeV. As a consequence of the substantial efforts of developing rf cavity, we decide to make a compact RF accelerating structure with more cell for achieving a smaller system. The measurement results of using the 3.5 cell rf gun, the design of 12 cell booster cavity, and current status of 12 cell cavity manufacturing will be presented at the conference.

MOPC030	The C-band Traveling-wave Accelerating Structure for Compact XFEL at SINAP*	vacuum, controls, impedance, status	133
	W. Fang, Q. Gu, Z.T. Zhao SINAP, Shanghai, People's Republic of China D.C. Tong TUB, Beijing, People's Republic of China
	The R&D of C-band accelerating structure has been launched two years ago at Shanghai Institute of Applied Physics, it will be used for the future compact hard X-ray FEL. The 1st C-band traveling-wave accelerating structure is ready for the high power test now. This structure is the preliminary model for the research of the technology of microwave test and tuning, arts and crafts and high power test. This paper presents the process of fabrication, cold test and tuning results.

MOPC032	Improvement of the RF System for the PEFP 100 MeV Proton Linac*	LLRF, controls, proton, EPICS	139
	K.T. Seol, Y.-S. Cho, H.S. Kim, H.-J. Kwon, Y.-G. Song KAERI, Daejon, Republic of Korea
	Funding: This work is supported by the Ministry of Education, Science and Technology of the Korean Government. The 100 MeV proton linear accelerator of the Proton Engineering Frontier Project (PEFP) has been developed and will be installed in Gyeong-ju site. The 20 MeV accelerator operated in Korea Atomic Energy Research Institute (KAERI) site will be also moved and reinstalled. The LLRF control systems for the 20 MeV accelerator were improved and have been operated within the stability of ±1% in RF amplitude and ±1 degree in RF phase. 7 sets of the extra LLRF control system will be installed with a RF reference system for the 100 MeV accelerator. Waveguide layout was also improved to install HPRF systems for the 100 MeV accelerator. Some of the HPRF components including klystrons, circulators, and RF windows are under purchase. The waveguide sections penetrating into the tunnel, which are fixed in a concrete floor with the bending structure for radiation shielding, were fabricated into a piece of waveguide to prevent the moisture and any foreign debris inside the concrete block. The details of the RF system improvement are presented.

MOPC035	Design and Machine Features of 2.2-m C-band Accelerating Structure	cavity, accelerating-gradient, vacuum, electron	148
	C.H. Yi, M.-H. Cho, S.H. Kim, H. Lee POSTECH, Pohang, Kyungbuk, Republic of Korea W. Namkung PAL, Pohang, Kyungbuk, Republic of Korea
	Funding: This work is partly supported by the MEST, Korea and POSTECH BK21 Program. And this work was supported by the Korea Student Aid Foundation (KOSAF) grant funded by the Korea government. A compact linac system is designed using a longer accelerating column in a C-band linac. It reduces the total number of RF units for the given linac beam energy and results in the cost-effective use of RF powers. For the 10 GeV PAL-XFEL project, a C-band accelerating column of 2.2-m long is investigated, which is 22% longer than 1.8-m for the SACLA at SPring-8. The detailed RF and thermal characteristics are presented by an analytic model.

MOPC042	RF and Accelerating Structure of 12 MeV UPC Race-track Microtron	vacuum, coupling, microtron, controls	169
	Yu.A. Kubyshin, X. Gonzalez Arriola UPC, Barcelona, Spain D. Carrillo, L. García-Tabarés, F. Toral CIEMAT, Madrid, Spain S.J. Mathot CERN, Geneva, Switzerland G. Montoro EPSC, Castelldefels, Spain V.I. Shvedunov MSU, Moscow, Russia
	We describe the design and technical characteristics of a C-band SW accelerating structure of a 12 MeV race-track microtron, which is under construction at the Technical University of Catalonia, and its RF system with a 5712 MHz magnetron as a source. Results of cold tests of the accelerating structure, before and after the brazing, and of high-power tests of the RF system at a special stand are reported. The main features of the magnetron frequency stabilization subsystem are also outlined.

MOPC043	Electromagnetic Simulations of the Input Power Couplers for the ESS-Bilbao RFQ	rfq, vacuum, cavity, radio-frequency	172
	O. Gonzalez, I. Bustinduy, N. Garmendia, J.L. Munoz, A. Velez ESS Bilbao, Bilbao, Spain F.J. Bermejo Bilbao, Faculty of Science and Technology, Bilbao, Spain V. Etxebarria, J. Portilla University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain
	An input power system is currently being designed at ESS-Bilbao in order to inject the RF power provided by a klystron into the RFQ as part of the linac. In this work, some input power couplers based on a coaxial topology are carefully studied from an electromagnetic point of view. As we will show, the electrical properties of the ceramic window used to ensure the vacuum of the RFQ crucially deteriorates the matching of the devices. To overcome this drawback, a full-wave electromagnetic simulator is used to optimize the coupler dimensions in order to minimize both the return and insertion losses.

MOPC047	RF Design of the Re-buncher Cavities for the LIPAC Deuteron Accelerator	cavity, impedance, vacuum, beam-transport	184
	A. Lara, I. Podadera, F. Toral CIEMAT, Madrid, Spain
	Funding: Work partially supported by Spanish Ministry of Science and Innovation under project ENE2009-11230. Re-buncher cavities are an essential component of LIPAC (Linear IFMIF Prototype Accelerator), presently being built at Rokkasho (Japan). The deuteron beam exiting from the RFQ (Radio Frequency Quadrupole) structure has to be properly adapted to the superconducting RF (SRF) linac. Re-bunchers are placed in the Medium Energy Beam Transport (MEBT) line and their objective is to longitudinally focus the deuteron beam. IFMIF re-bunchers must provide a 350 kV E0LT at 175 MHz continuous wave (CW). The available length for the re-buncher is limited by the general layout of the MEBT. The high power dissipation derived from the high effective voltage and the short available length is an important design challenge. Four different normal conducting cavity designs were investigated: the pillbox type, double gap coaxial resonators, and multi-gap quarter wave and H resonators. The performance of these cavities was studied with the numerical codes HFSS and ANSYS. The fundamental frequency and field pattern of each re-buncher was investigated in HFSS. This work presents the results of such analyses.

MOPC053	Mechanical Design and Fabrication Studies for SPL Superconducting RF Cavities	cavity, niobium, SRF, proton	199
	S. Atieh, G. Arnau-Izquierdo, I. Aviles Santillana, O. Capatina, T. Renaglia, T. Tardy, N. Valverde Alonso, W. Weingarten CERN, Geneva, Switzerland
	CERN’s R&D programme on the Superconducting Proton Linac’s (SPL) superconducting radio frequency (SRF) elliptical cavities made from niobium sheets explores new mechanical design and consequently new fabrication methods, where several opportunities for improved optimization were identified. A stainless steel helium vessel is under design rather than a titanium helium vessel using an integrated brazed transition between Nb and the SS helium vessel. Different design and fabrication aspects were proposed and the results are discussed hereafter.

MOPC055	High Power Test of the First PIMS Cavity for Linac4	cavity, pick-up, vacuum, klystron	205
	F. Gerigk, J.-M. Giguet, P. Ugena Tirado, R. Wegner CERN, Geneva, Switzerland
	The PI-Mode Structure (PIMS) accelerates the Linac4 beam from 100 to 160 MeV. Twelve 7-cell cavities will be installed in the linac, with a gradient of ~4 MV/m and operating at a frequency of 352.2 MHz. A full-power prototype has been constructed at CERN in 2010 and was high- power tested in autumn 2010. Peak power tests at the Linac4 duty cycle and high-average power tests at increased duty cycles were completed successful, so that this prototype will be the first of the 12 cavities to be installed in Linac4. This paper reports on the high-power tests and the conditioning experience.

MOPC056	The Linac4 Power Coupler	cavity, coupling, vacuum, simulation	208
	F. Gerigk, J.-M. Giguet, E. Montesinos, B. Riffaud, P. Ugena Tirado, R. Wegner CERN, Geneva, Switzerland
	Linac4 employs 3 types of accelerating structures after the RFQ: a Drift Tube Linac (DTL), a Cell-Coupled DTL (CCDTL), and a Pi-Mode Structure (PIMS) to accelerate the beam to 160 MeV. The structures are designed for a peak power of 1 MW per coupler, which consists of two parts: a ceramic window, which separates the cavity vacuum from the air in the wave-guides, and a so-called "coupling T", which couples the RF power through an iris to the cavity. In the frame of the Linac4 R&D both devices have been significantly improved with respect to their commonly used design. On the coupler side, the wave-guide short circuit with its matched length has been replaced by a fixed length λ/4 short circuit. The RF matching is done by a simple piston tuner, which allows a quick matching to different cavity quality factors. In the window part, which usually consists of a ceramic disc and 2 pieces of wave-guides with matching elements, the wave-guide sections could be completely suppressed, so that the window became very compact, lightweight, and much simpler to manufacture. In this paper we present electromagnetic simulations, and tests on first prototypes, which were constructed at CERN.

MOPC059	The Plane Wave Transformer Linac Development at NSRRC	simulation, impedance, cavity, electron	217
	A. Sadeghipanah, J.-Y. Hwang, W.K. Lau NSRRC, Hsinchu, Taiwan T.H. Chang NTHU, Hsinchu, Taiwan
	A Plane-Wave-Transformer (PWT), standing wave linac operating at S-band frequency (2.9979 GHz) is being developed at NSRRC. This structure offers the advantages of high efficiency, compactness, fabrication simplicity and cost. The PWT prototype at NSRRC consists of three cells with two half-cells at the ends, separated by a set of four flat disks suspended and cooled by four water tubes inside a large cylindrical tank. To fully understand its physical properties, numerical modeling of the PWT prototype has been carried out by using the 2-D code SUPERFISH and 3-D code MAFIA. In this paper, we describe the principle properties of this structure, the electric parameters obtained from numerical simulations, and heat dissipation calculation. The mechanical design for prototype linac is also reported.

MOPC060	Bunching-frequency Multiplication for a THz Pulse-train Photoinjector	electron, bunching, laser, acceleration	220
	Y.-C. Huang, F.H. Chao, C.H. Chen, K.Y. Huang NTHU, Hsinchu, Taiwan
	Funding: This work is supported by National Science Council under Contract NSC 99-2112-M-007 -013 -MY3. A THz-pulse-train photoinjector* employs a THz-pulse-train laser as its driver laser to generate a beam with a bunching frequency in the THz range. However a laser frequency is on the order of a few hundred THz. It is not possible to generate a beam from the pulse-train photoinjector with a bunching frequency exceeding the laser’s carrier frequency. In view of the strong demand for a compact x-ray free-electron laser (FEL), it is highly desirable to multiply the bunching frequency of the beam from a pulse-train injector to the x-ray frequencies. We propose to chirp the energy of the THz electron pulse train in an accelerator and compress the whole beam in a magnet to increase the electron bunching frequency. Our study shows a compression ratio or a bunching-frequency multiplication factor of a few tens is achievable from a properly designed magnetic chicane compressor. The bunching factor, however, is unfortunately degraded due to the energy chirp, emittance growth, and wake-field generation. In the conference, we will show that a bunching factor of a few ppm in the bunch-frequency multiplied beam is sufficient to build up the FEL power from a 10-time length reduced undulator. * Y. C. Huang, “Laser-beat-wave bunched beam for compact superradiance sources,” International Journal of Modern Physics B, Vol. 21 Issue 3/4, p277-286 (2007).

MOPC068	LANSCE RF System Improvements for Current and Future Programs*	klystron, cavity, neutron, proton	238
	D. Rees, J.L. Erickson, R.W. Garnett, J.T.M. Lyles, L. Rybarcyk LANL, Los Alamos, New Mexico, USA
	The Los Alamos Neutron Science Center (LANSCE) is in the midst of an upgrade of the RF systems. This project will return LANSCE to its historical operating capability and sustain facility operations into the next decade. The LANSCE accelerator provides pulsed protons and spallation neutrons for defense and civilian applications. This project involves replacing all the existing 201 MHz RF stations and 805 MHz klystrons. LANSCE is also currently in the conceptual design phase of a program called the Material Test Station (MTS) to establish a 1 MW target station to irradiate fast reactor fuels and materials. A pre conceptual design is also in progress to extend the capabilities of MTS to a 2 MW target that will enable the first in a new generation of scientific facilities for the materials community. The emphasis of this new facility is "Matter-Radiation Interactions in Extremes" (MaRIE) which will be used to discover and design the advanced materials needed to meet 21st century national security and energy security challenges. The design and test results of the new RF systems will be presented as well as the RF system changes required to support the new missions.

MOPC072	Design of an RF Feed System for Standing-wave Accelerator Structures	cavity, coupling, wakefield, damping	244
	J. Neilson, V.A. Dolgashev, S.G. Tantawi SLAC, Menlo Park, California, USA
	Travelling wave (TW) accelerator structures are known to suffer from several deficiencies. A breakdown in one of the cells propagates towards the source. This results in damage to upstream cells in addition to the cell where the breakdown was initiated. The deficiencies of TW accelerator structures can be overcome by using standing wave (SW) cells that are fed in parallel. An RF breakdown is contained to the cell where it originates. This eliminates upstream cell damage and the resulting changes in phase shift between cells. In addition the feed structure can provide a high conductance port for vacuum pumping. We have completed the design of a parallel fed SW structure with a directional coupler for each cell and serpentine waveguide connection between couplers. This design approach improves isolation between the cells resulting in the maximum increase in the operational robustness of the accelerator structure. The design uses four feed arms spaced uniformly around the cell circumference to suppress dipole modes and improve damping of low order wakefields. Construction of a test structure in now underway and is scheduled for testing in October of this year.

MOPC079	Status of the Low Beta 0.07 Cryomodules for SPIRAL2	cavity, cryomodule, LLRF, vacuum	256
	P. Bosland, P. Carbonnier, F. Eozénou, P. Galdemard, O. Piquet CEA/DSM/IRFU, France M. Anfreville, C. Madec, L. Maurice CEA/IRFU, Gif-sur-Yvette, France P.-E. Bernaudin, R. Ferdinand GANIL, Caen, France Y. Gomez-Martinez LPSC, Grenoble Cedex, France A. Pérolat CEA, Gif-sur-Yvette, France
	The status of the low beta cryomodules for SPIRAL2, supplied by the Irfu institute of CEA Saclay, is reported in this paper. We summarise in three parts the RF tests performed on the cavities in vertical cryostat, the RF power tests of the qualifying cryomodule performed in 2010 and the RF power tests performed in 2011 on the first cryomodule of the series

MOPC080	First Considerations Concerning an Optimized Cavity Design for the Main Linac of BERLinPro	cavity, HOM, coupling, impedance	259
	B. Riemann, T. Weis DELTA, Dortmund, Germany W. Anders, J. Knobloch, A. Neumann HZB, Berlin, Germany H.-W. Glock, C. Potratz, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany F. Marhauser JLAB, Newport News, Virginia, USA
	Funding: work supported by BMBF under contracts 05K10PEA and 05K10HRC The Berlin Energy Recovery Linac Project (BERLinPro) is designed to develop and demonstrate CW linac technology and expertise required to drive next-generation Energy Recovery Linacs. Strongly HOM-damped multicell 1.3 GHz cavities are required for the main linac. The optimization of the cavities presented here is primarily based on the CEBAF 1.5 GHz 5-cell high-current cavity design, including HOM waveguide couplers. The cavity was scaled to 1.3 GHz and extended to 7 cells. Modifications to the end group design have also been studied. An effort was also made to reduce the ratio Epk/Eacc while still permitting HOMs to propagate.

MOPC082	Status of the 325 MHz SC CH-Cavity at IAP Frankfurt	cavity, simulation, status, electron	265
	M. Busch, F.D. Dziuba, H. Podlech, U. Ratzinger IAP, Frankfurt am Main, Germany M. Amberg, K. Aulenbacher HIM, Mainz, Germany W.A. Barth, S. Mickat GSI, Darmstadt, Germany
	Funding: BMBF contract no. 06FY161I At the Institute for Applied Physics (IAP), University of Frankfurt, a s.c. 325 MHz CH-Cavity is under development for future beam tests at GSI UNILAC, Darmstadt. The cavity with 7 accelerating cells has a geometrical beta of 0.15 corresponding to 11.4 AMeV. The design gradient is 5 MV/m. The geometry of this resonator was optimized with respect to a compact design, low peak fields, surface processing, power coupling and tuning. Furthermore a new tuning system based on bellow tuners inside the resonator will control the frequency during operation. After rf tests in Frankfurt the cavity will be tested with a 10 mA, 11.4 AMeV beam delivered by the GSI UNILAC. In this paper rf simulations, multipacting analysis as well as thermal calculations will be presented.

MOPC083	Structural Mechanics of Superconducting CH Cavities	cavity, simulation, controls, resonance	268
	M. Amberg, K. Aulenbacher HIM, Mainz, Germany W.A. Barth, S. Mickat GSI, Darmstadt, Germany M. Busch, F.D. Dziuba, H. Podlech, U. Ratzinger IAP, Frankfurt am Main, Germany
	The superconducting CH-structure (Crossbar-H-mode) is a multi-cell drift tube cavity for the low and medium energy range operated in the H21-mode, which has been developed at the Institute for Applied Physics (IAP) of Frankfurt University. With respect to different high power applications two types of superconducting CH-structures (f = 325 MHz, β = 0.16, seven cells and f = 217 MHz, β = 0.059, 15 cells) are presently under construction and accordingly under development. The structural mechanical simulation is a very important aspect of the cavity design. Furthermore, several simulations with ANSYS Workbench have been performed to predict the deformation of the cavity walls due to the cavity cool-down, pressure effects and mechanical vibrations. To readjust the fast frequency changes in consequence of the cavity shape deformation, a new concept for the dynamic frequency tuning has been investigated, including a novel type of bellow-tuner.

MOPC084	The Superconducting cw LINAC Demonstrator for GSI	cavity, solenoid, ion, acceleration	271
	F.D. Dziuba, M. Busch, H. Podlech, U. Ratzinger IAP, Frankfurt am Main, Germany M. Amberg, K. Aulenbacher HIM, Mainz, Germany W.A. Barth, S. Mickat GSI, Darmstadt, Germany
	Funding: BMBF Contr. No. 06FY9089I, Helmholtz Institut Mainz At GSI a new, superconducting (sc) continuous wave (cw) LINAC is under design in cooperation with the Institute for Applied Physics (IAP) of Frankfurt University and the Helmholtz Institut Mainz (HIM). This proposed LINAC is highly requested by a broad community of future users to fulfill the requirements of nuclear chemistry, nuclear physics, and especially in the research field of Super Heavy Elements (SHE). In this context the preliminary layout of the LINAC has been carried out by IAP. The main acceleration of up to 7.3 AMeV will be provided by nine sc Crossbar-H-mode (CH) cavities operated at 217 MHz. Currently, a prototype of the cw LINAC as a demonstrator is under development. The demonstrator comprises a sc CH-cavity embedded between two sc solenoids mounted in a horizontal cryomodule. A full performance test of the demonstrator in 2013/14 by injecting and accelerating a beam from the GSI High Charge Injector (HLI) is one important milestone of the project. The status of the demonstrator is presented.

MOPC085	Quality Assessment for Industrially Produced High-Gradient Superconducting Cavities	cavity, niobium, superconducting-cavity, SRF	274
	F. Schlander, S. Aderhold, E. Elsen, D. Reschke, M. Wenskat DESY, Hamburg, Germany
	Funding: This work is supported by the Commission of the European Communities under the 7th Framework Programme “Construction of New Infrastructures – Preparatory Phase”, contract number 206711. A series of some 600 superconducting 1.3 GHz cavities will start being delivered to DESY by industry in early 2012. Although a considerably smaller gradient satisfies the needs for the European XFEL the electro-polished cavities (50% of the delivery) are deemed to be suitable for gradients in excess of 35 MV/m, the performance goal of the International Linear Collider (ILC). Specifically 24 cavities will be supplied without helium tank to enable further investigations. The results may serve to improve overall performance; limitations such as field emission and thermal breakdown of superconductivity ("quench") are still under investigation. For this matter the DESY ILC group has developed tools to monitor aspects of the cavity fabrication. An automated optical mapping system (OBACHT) is being commissioned and will be complemented by software for automated cavity surface feature recognition. For cold RF tests a Second Sound setup for locating the positions of the thermal breakdown is routinely used. These diagnostic tools will give guidance on post-processing cavities for best performance. The current status of these projects will be described.

MOPC088	Bead-pull Measurement using Phase-Shift Technique in Multi-cell Elliptical Cavity	cavity, vacuum, controls, monitoring	280
	S. Ghosh, A. Mandal, S. Seth, S.S. Som DAE/VECC, Calcutta, India
	The project on the development of high-beta multi-cell elliptical shape superconducting rf linac cavity at around 704 MHz has been funded at VECC, Kolkata, India. A full-scale copper prototype cavity has been designed and fabricated. There are 5 distinct modes exist in the cavity and the accelerating mode is pi-mode in which each cell operates at same frequency with phase difference of 180 degrees between two neighboring cells. A fully automated bead-pull measurement setup has been developed for analyzing these modes and field profile distribution at different modes in such type of linac cavity. A special measurement method inside the cavity using phase-shift technique is proposed in this paper, which describes the development of mechanical setup comprising pulleys and stepper motor–gear arrangement, PC-based control system for precise movement of bead using stepper motor, measurement using VNA, development of software for data acquisition & automation and measurement results for the 5-cell copper prototype cavity.

MOPC089	RF Simulations for the QWR Cavities of PIAVE-ALPI	cavity, simulation, ion, beam-losses	283
	M. Comunian, F. Grespan, A. Palmieri INFN/LNL, Legnaro (PD), Italy
	The PIAVE-ALPI linac is composed of several families of QWR cavities. In order to have a thorough description of the accelerator in terms of beam dynamics, a detailed field mapping of the accelerating cavities is necessary, including non-linear behavior of the off-axis fields, as well as the steering and dispersion effects due to transverse components. For such a purpose, a set of RF simulation was accomplished, with the codes HFSS and COMSOL. The details about these simulations and the main outcomes and results will be described in this article.

MOPC091	Status of the XFEL 3.9 GHz Injector Section	cavity, cryogenics, cryomodule, status	289
	P. Pierini, M. Bonezzi, A. Bosotti, M. Fusetti, P.M. Michelato, L. Monaco, R. Paparella, D. Sertore INFN/LASA, Segrate (MI), Italy E. Vogel DESY, Hamburg, Germany
	The European XFEL will use a superconducting third harmonic section to achieve the necessary beam quality for the FEL process. The concept has been successfully proven at the FLASH linac in DESY, with a 4 cavity superconducting module contributed by FNAL. The design of the third harmonic system at the XFEL injector is being finalized and prototypes of the components (cavities and couplers) have been fabricated and are currently in the testing stage. The paper will provide a status of the activities.

MOPC095	Superconducting Cavity R&D for ILC at MHI	cavity, HOM, superconducting-cavity, status	298
	H. Hitomi, H. Hara, F. Inoue, K. Kanaoka, K. Sennyu, T. Yanagisawa MHI, Kobe, Japan
	We have developed and manufactured some superconducting RF cavity for STF project in KEK. In recent vertical test in KEK, the MHI-#12 cavity which is one of cavities for STF phase 2 project reached ILC specification(max Eacc was about 40MV/m). So techniques for manufacturing cavity is making steady progress in MHI. To be realized ILC project, we also try to decrease the manufacturing cost by using some new techniques, for example Laser Beam Welding, deep drawing, seamless dumbbell, etc. In this meeting, we will report recent MHI's activities for ILC.

MOPC101	Vertical Test of PEFP Prototype SRF Cavity	cavity, accelerating-gradient, electron, SRF	307
	H.S. Kim, Y.-S. Cho, H.-J. Kwon KAERI, Daejon, Republic of Korea
	Funding: This work was supported by Ministry of Education, Science and Technology of the Korean Government. The PEFP Proton linac is a 100-MeV machine which consists of a proton injector, a 3-MeVRFQ and 100-MeV DTL. For the extension of the machine beyond 100 MeV, SRF technology is under consideration. As a prototyping activity, a superconducting RF cavity with a geometrical beta of 0.42 and a resonant frequency of 700 MHz has been designed, fabricated and tested. The cavity is an elliptical shape with 5 cells stiffened by double-ring structure. A design accelerating gradient is 8.0 MV/m at the operating temperature of 4.2 K and maximum duty factor is 9%. For the vertical test of the cavity, a cryostat with a vacuum jacket and multi-layer insulation was prepared. The RF system for driving the cavity is based on PLL to track the resonant frequency. In case of lack of RF power, a two-way RF power combiner based on splitted coaxial transmission line is considered. The details of the vertical test setup and test results will be presented in this paper.

MOPC109	Suppression of Coupler Kicks in 7-Cell Main Linac Cavities for Cornell's ERL	cavity, emittance, resonance, simulation	331
	N.R.A. Valles, M. Liepe, V.D. Shemelin CLASSE, Ithaca, New York, USA
	Funding: Supported by NSF award DMR-0807731 Cornell is developing a 5 GeV Energy Recovery Linac operating at 100 mA with very small emittances (~30 pm at 77 pC bunch charge) in the horizontal and vertical directions. We investigate the effect of the fundamental RF power couplers of the main linac SRF cavities on the beam using the ACE3P software package. The cavities in the ERL main linac will be operated at very high loaded quality factors of up to 6.5·10⁷, corresponding to a full bandwidth of only 20 Hz. Cavity microphonics will detune the cavities by more than one bandwidth during operation, thereby causing a time dependent change of the coupler kick in addition to its fast oscillation at the RF frequency. In order to investigate the dependence of the coupler kick on the cavity frequency, we calculate the coupler kick given to the beam for the case of a detuned RF cavity. We show that a compensation stub geometry located opposite to the input coupler port can be optimized to reduce the overall kick given to the beam and the emittace growth caused by its time dependence.

MOPC114	Design, Fabrication and Testing of Medium-Beta 650 MHz SRF Cavity Prototypes for Project-X	cavity, SRF, electron, vacuum	343
	F. Marhauser, W.A. Clemens, J. Henry, P. Kneisel, R. Martin, R.A. Rimmer, G. Slack, L. Turlington, R.S. Williams JLAB, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. A new type of superconducting radio frequency (SRF) cavity shape with a shallow equator dome to reduce electron impact energies for suppressing multipacting barriers has been proposed. The shape is in consideration for the first time in the framework of Project-X to design a potential multi-cell cavity candidate for the medium-beta section of the SRF proton CW linac operating at 650 MHz. Rationales covering the design of the multi-cell cavity, the manufacture, post-processing and high power testing of two single-cell prototypes are presented.

MOPC121	Design of Low-frequency Superconducting Spoke Cavities for High-velocity Applications	cavity, impedance, HOM, superconductivity	364
	J.R. Delayen, C.S. Hopper ODU, Norfolk, Virginia, USA R.G. Olave Old Dominion University, Norfolk, Virginia, USA
	Superconducting single- and multi-spoke cavities have been designed to-date for particle velocities from β~0.15 to β~0.65. Superconducting spoke cavities may also be of interest for higher-velocity, low-frequency applications, either for hadrons or electrons. We present the design of 325 and 352 MHz spoke cavities optimized for β=0.8 and β=1.

MOPC123	Temperature Dependent Microphonics in the BNL Electron Cooler*	resonance, cavity, electron, cryogenics	370
	P. Jain Stony Brook University, Stony Brook, USA I. Ben-Zvi, C. Schultheiss BNL, Upton, Long Island, New York, USA
	An R&D Energy Recovery Linac (ERL), to be used in the BNL electron cooler, has been operational in a developmental setting. The ERL requires a cryogenic system to supply cooling to a superconducting RF gun and the 5-cell superconducting RF cavity system that is kept cold at 2K. The 2K superfluid bath is produced by pumping on the bath using a sub-atmospheric warm compression system. During a test run in October 2010, a resonance peak corresponding to a noise of 30 Hz was observed at 1.88K. This noise peak, present at all temperatures below 2K, is assumed to be of mechanical origin from the vibration of the cryopump. Another resonance noise peak of 16 Hz, characteristic of the system, was observed at 1.98K, which shifted towards the 30 Hz peak as the temperature of the cryostat varied from 1.98K to 1.88K. The 16 Hz resonance peak upon hitting the 30 Hz resonance peak, sets a resonance condition, thereby the 30 Hz peak getting amplified by more than five times. In this paper we explore the origin of the temperature dependent 16 Hz resonance peak and give a physical explanation of the resonance.

MOPC126	High Power RF System for TRIUMF E-Linac Injector	cavity, klystron, TRIUMF, cryomodule	373
	A.K. Mitra, Z.T. Ang, S. Calic, S.R. Koscielniak, R.E. Laxdal, R.W. Shanks, Q. Zheng TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
	TRIUMF has been funded to build the first stage of an electron linac with a final energy of 50 MeV and 500 kW beam power. The e-linac consists of an injector section with electron gun with 650 MHz rf modulated grid, a room temperature 1.3 GHz buncher cavity, and injector cryomodule, and two main-linac cryomodules for the accelerating section to be installed sequentially. The injector module has one 9 cell cavity whereas each of the accelerating cryomodules contains two 9-cell SC cavities. The injector cryomodule will be fed by a 30 kW cw Inductive Output Tube (IOT)and the accelerating cryomodule will be powered by a cw klystron. A first goal is a beam test of the e-Linac injector to 10MeV in 2012. Installation and full rated output power tests of the IOT on a 50 ohms load have been carried out. The IOT is purchased from CPI, USA while the transmitter is sourced from Bruker BioSpin. A power coupler conditioning station utilizes the same IOT. The buncher cavity is driven from a Bruker 600W amplifier. In this paper, the conceptual design of the e-Linac rf system will be summarized and the high power rf system for the injector including IOT measurement results will be presented. SC stands for superconducting

MOPC128	16 kW Upgrade of the 1.3 GHz ELBE RF-system (CW) with Solid State Amplifiers	klystron, rf-amplifier, cavity, superconducting-cavity	379
	H. Büttig, A. Arnold, A. Büchner, M. Justus, M. Kuntzsch, U. Lehnert, P. Michel, R. Schurig, G.S. Staats, J. Teichert HZDR, Dresden, Germany
	The superconducting CW- LINAC of the radiation source ELBE is in permanent operation since May 2001. In 2011 an upgrade program of ELBE is in progress to support additional applications. One part of the program is to double the RF-power per cavity to at least 16 kW. We first tested a 30 kW IOT-based amplifier (Bruker /CPI) at a cavity, later two 10 kW solid state amplifiers in parallel. The best solution found is based on 10 kW Solid State Power Amplifiers (SSPA) developed by Bruker BioSpin. The poster gives an overview on the status, the activities around this RF-upgrade project and the technical specification of the “turnkey” SSPA , designed for 10 kW, 1.3 GHz and full CW-operation.

MOPC129	Compact Solid State RF-Modules for Direct Drive RF-linacs	impedance, vacuum, cavity, klystron	382
	R. Irsigler, M. Back, R. Baumgartner, O. Heid, T.J.S. Hughes, M. Kaspar, T. Kluge, J. Sirtl, K. Weidner, M. Zerb Siemens AG, Erlangen, Germany
	We present a modular RF power source concept based on solid state RF-modules with novel SiC transistors. The concept offers lower cost, better reliability and reduced maintenance compared to traditional RF-source technology. No circulators are required, which makes the RF-module very compact and reliable. The SiC power transistor has a very low input capacitance and was optimized for low gate resistance to enable fast switching in the VHF range. It delivers a maximum pulsed drain saturation current of 65 A. The transistor provides at 350 V supply voltage and 150 MHz an output power of 5,6 kW at a gain of 15,8 dB. It is essential to avoid high parasitic source inductances at RF and good thermal conductivity is required for operation at high duty cycle. We have built very compact 75 x 90 mm ceramic amplifier modules using a planar interconnect technology (SIPLIT) to connect the bare die transistors to the DCB substrate. The modules have a fully symmetric push-pull topology (circlotron) with four transistors in parallel in each leg. The RF-modules delivered at 150 MHz an impressive RF output power in the range of 40 kW. Further tests at 324 MHz are planned and will be presented.

MOPC135	IFMIF-EVEDA RF Power System	controls, power-supply, LLRF, cavity	394
	D. Regidor, A. Arriaga, J.C. Calvo, A. Ibarra, I. Kirpitchev, J. Molla, P. Méndez, A. Salom, M. Weber CIEMAT, Madrid, Spain M. Abs, B. Nactergal IBA, Louvain-la-Neuve, Belgium P.-Y. Beauvais, M. Desmons, A. Mosnier CEA/DSM/IRFU, France P. Cara Fusion for Energy, Garching, Germany S.J. Ceballos, J. de la Cruz Greenpower Technologies, Sevilla, Spain Z. Cvetkovic, Z. Golubicic, C. Mendez TTI, Santander, Spain J.M. Forteza, J.M. González, C.R. Isnardi Indra Sistemas, San Fernando de Henares, Spain D. Vandeplassche SCK-CEN, Mol, Belgium
	The IFMIF/EVEDA Accelerator Prototype will be a 9 MeV, 125 mA CW deuteron accelerator to validate the technical options for the IFMIF accelerator design. The Radiofrequency Quadrupole (RFQ), buncher cavities and Superconducting Radiofrequency Linac (SRF Linac) require continuous wave RF power at 175 MHz with an accuracy of ±1% in amplitude and ±1° in phase. Also the IFMIF/EVEDA RF Power System has to work under pulsed mode operation (during the accelerator commissioning). The IFMIF/EVEDA RF Power System is composed of 18 RF power generators feeding the eight RFQ couplers (200 kW), the two buncher cavities (10⁵ kW) and the eight superconducting half wave resonators of the SRF Linac (10⁵ kW). The main components of each RF power chain are the Low Level Radio Frequency system (LLRF), three amplification stages and a circulator with its load. For obvious standardization and scale economies reasons, the same topology has been chosen for the 18 RF power chains: all of them use the same main components which can be individually tuned to provide different RF output powers up to 200 kW. The studies and the current design of the IFMIF/EVEDA RF Power System are presented in this contribution.

MOPC136	The RF Power Source for the High Beta Elliptical Cavities of the ESS Linac	klystron, cavity, neutron, LLRF	397
	K. Rathsman, H. Danared, R. Zeng ESS, Lund, Sweden A.J. Johansson Lund University, Lund, Sweden C. Lingwood Cockcroft Institute, Lancaster University, Lancaster, United Kingdom R.J.M.Y. Ruber Uppsala University, Uppsala, Sweden C. de Almeida Martins IST-UTL, Lisbon, Portugal
	The European Spallation Source is an intergovernmental project building a multidisciplinary research laboratory based upon the world’s most powerful neutron source. The main facility will be built in Lund, Sweden. Construction is expected to start around 2013 and the first neutrons will be produced in 2019. The ESS linac delivers 5 MW of power to the target at 2.5 GeV, with a nominal current of 50 mA. The 120 high beta elliptical cavities, which operate at a frequency of 704 MHz and accelerate protons from 600 MeV to 2.5 GeV, account for more than half of the total number of rf cavities in the ESS linac and three quarter of the total beam power needed. Because of the large number of rf power sources and the high power level needed, all the design and development efforts for the rf power source have so far been focused on this part of the accelerator. The design and development status of the rf power source is reported in this paper with emphasis on reliability, maintainability, safety, power efficiency, investment cost and production capacity.

MOPC137	Medium Power 352 MHz Solid State Pulsed RF Amplifiers for the CERN Linac4 Project	controls, cavity, rf-amplifier, shielding	400
	J.C. Broere, J. Marques Balula CERN, Geneva, Switzerland Y. Gomez LPSC, Grenoble Cedex, France M. Rossi DBE, Padova, Italy
	Economic, modular and highly linear pulsed RF amplifiers have recently been developed to be used for the three Buncher cavities in the CERN Linac4. The amplifiers are water cooled and can provide up to 33 kW pulsed RF power, 1.5 msec pulse length and 50 Hz repetition rate. Furthermore a 60 kWatt unit is under construction to provide the required RF Power for the Debuncher cavity. The concept is based on 1.2 kW RF power modules using the latest 6th generation LDMOS technology. For integration into the CERN control environment the amplifiers have an internal industrial controller, which will provide easy control and extended diagnostic functions. This paper describes the construction, performance, including linearity, phase stability and EMC compliance tests.

MOPC138	Practical Test of the Linac4 RF Power System	klystron, cavity, controls, electron	403
	N. Schwerg, O. Brunner CERN, Geneva, Switzerland
	Linac4 is a linear accelerator for negative Hydrogen ions which will replace the old Linac2 as injector for the CERN accelerators. Its higher energy of 160 MeV will increase the beam intensity in the downstream machines. The normal-conducting accelerating structures are housed in a 100 m long tunnel which will be connected to the existing chain of accelerators and can be extended into a new injector chain. The high RF power for the Linac4 accelerating structures will be generated by thirteen 1.3 MW klystrons, previously used for the CERN LEP accelerator, and six new klystrons of 2.8 MW all operating at a frequency of 352.2 MHz. The re-use of existing LEP equipment, space limitations in the installation and tight phase and amplitude constraints pose a number of challenges for the integration of the RF power system. The power distribution scheme features a folded magic-tee feeding the power from a 2.8 MW klystron to two LEP circulators. We present first results from the Linac4 test place, validating the approach and the used components as well as reporting on the klystron re-tuning activities.

MOPC142	25 Year Performance Review of the SLAC 5045 S-Band Klystron	klystron, high-voltage, cathode, linear-collider	409
	A. Jensen, A.S. Beebe, M.V. Fazio, A.A. Haase, E.N. Jongewaard, C. Pearson, D.W. Sprehn, A.E. Vlieks, L.E. Whicker SLAC, Menlo Park, California, USA
	Funding: This work was supported by the U.S. Department of Energy under contract DE-AC03-76SF00515. The SLAC 5045 S-band klystron has proven to be a remarkably reliable high peak power tube. Originally developed in the 1980’s as an upgraded RF power source for the Stanford Linear Collider, it has continually powered the SLAC linac in support of numerous programs in particle physics and photon science. The large number of tubes built and operated (more than 800) coupled with accumulated running statistics over the last 25+ years represents an unprecedented wealth of operational experience for high pulse power klystrons in accelerator applications. Mean time between failures has continued to rise during this period and is frequently in excess of 100,000 hours during the last several years. Lifetime statistics as well as some important failure modes are presented and examined here.

MOPC146	Development of Timing Distribution System with Femto-second Stability	feedback, controls, acceleration, laser	421
	T. Naito, K. Ebihara, S. Nozawa, N. Terunuma, J. Urakawa KEK, Ibaraki, Japan M. Amemiya AIST, Tsukuba, Japan
	A timing distribution system with femto-second stability has been developed for the RF synchronization of accelerator and the laser synchronization of the pump-probe experiments. The system uses a phase stabilized optical fiber(PSOF) and an active fiber length stabilization. The PSOF has 5 ps/km/degC of the temperature coefficient. The active fiber length stabilization uses the phase detection of the round-trip sinusoidal wave and the fiber stretcher for the compensation of the fiber length. In this paper, we present the test results on a 500 m long signal distribution. The preliminary results of the timing stability are 20 fs at several minutes and 100 fs at four days, respectively.

MOPC151	Design and Commissioning of a Multi-frequency Digital Low Level RF Control System*	cavity, controls, low-level-rf, superconducting-cavity	433
	M. Konrad, U. Bonnes, C. Burandt, J. Conrad, R. Eichhorn, J. Enders, P.N. Nonn, N. Pietralla TU Darmstadt, Darmstadt, Germany
	Funding: Work supported by DFG through CRC 634 and by the BMBF under 06 DA 9024 I. Triggered by the need to control the superconducting cavities of the S-DALINAC, which have a high loaded quality factor and are thus very susceptible to microphonics, the development of a digital low level RF control system was started. The chosen design proved to be very flexible since other frequencies than the original 3 GHz may be adapted easily: The system converts the RF signal coming from the cavity (e. g. 3 GHz) down to the base band using a hardware I/Q demodulator. The base band signals are digitized by ADCs and fed into a FPGA where the control algorithm is implemented. The resulting signals are I/Q modulated before they are sent back to the cavity. The superconducting cavities are operated with a self-excited loop algorithm whereas a generator-driven algorithm is used for the low Q normal-conducting bunching cavities. A 6 GHz RF front end allows the synchronous operation of a new 2f buncher at the S-DALINAC. Meanwhile, a 325 MHz version has been built to control a pulsed prototype test stand for the p-LINAC at FAIR. We will present the architecture of the RF control system as well as results obtained during operation.

MOPC152	Digital Control System for Solid State Direct Drive™ RF-Linacs	controls, cavity, LLRF, pick-up	436
	J. Sirtl, M. Back, T. Kluge Siemens AG, Erlangen, Germany H. Schröder ASTRUM IT GmbH, Erlangen, Germany
	The Solid State Direct Drive™ concept for RF linacs has previously been introduced. Due to the different methodology (i.e. solid state based rather than electron tube based) as compared with conventional RF sources a new control system is required to deliver the required LLRF. To support this new technology a fully digital control system for this new concept has been developed. Progresses in Digital – Analogue Converter technology and FPGA technology allows us to create a digital System which works in the 150 Mhz baseband. The complete functionality was implemented in a Virtex 6 FPGA. Dispensing with the PLL allows an excellent jitter-behaviour. For this job, we use three 12 bit ADCs with a Sampling Rate of 1 GS/s and two 16 bit DACs (1 GS/s). The amplitude of the RF source is controlled by dividing the RF modules mounted on the power combiner* into two groups and controlling the relative phase of each group (in effect mimicking an “out-phasing” amplifier). This allows the modules to be operated at their optimum working point and allows a linear amplitude behaviour. * O. Heid, T. Hughes, Proc. of IPAC10, THPD002, p. 4278, Kyoto, Japan (2010). ** O. Heid, T. Hughes, Proc. of LINAC10, THPD068, Tsukuba, Japan.

MOPC156	Operation Test of Distributed RF System with Circulator-less Waveguide Distribution in S1-Global Project at STF/KEK	cavity, klystron, feedback, superconducting-cavity	448
	T. Matsumoto, M. Akemoto, D.A. Arakawa, S. Fukuda, H. Honma, E. Kako, H. Katagiri, S. Matsumoto, H. Matsushita, S. Michizono, T. Miura, H. Nakajima, K. Nakao, T. Shidara, T. Takenaka, Y. Yano, M. Yoshida KEK, Ibaraki, Japan
	Distributed RF System (DRFS) is one candidate for a single main linac tunnel design of International International Linear Collider (ILC). In the DRFS, more than ten 800-kW klystrons having a modulating anode are operated by a common DC power and a modulation anode modulator. Each klystron feeds its power into two superconducting cavities and its waveguide distribution system is configured without circulators. This DRFS consists of four SC cavities, two klystrons and a modulator was demonstrated in S1-Global project. The results of circulator-less operation in the DRFS will be reported.

MOPC158	RF Capture of a Beam with Charge-exchanging Multi-turn Injection	injection, simulation, acceleration, closed-orbit	454
	T. Uesugi, Y. Ishi, Y. Kuriyama, J.-B. Lagrange, Y. Mori, R. Nakano, T. Planche, B. Qin, E. Yamakawa KURRI, Osaka, Japan Y. Niwa, K. Okabe, I. Sakai University of Fukui, Faculty of Engineering, Fukui, Japan
	Funding: This work was supported by MEXT of Japan in the framework of a task entitled ”Research and Development for an Accelerator-Driven Sub-critical System Using an FFAG Accelerator”. In the fixed field alternating gradient (FFAG) synchrotron in Kyoto university research reactor Institute (KURRI), charge exchange injection was adopted since 2011. The charge stripping foil is located on the closed orbit of the injection energy, and no bump orbit system is used. Instead, the injected beam escapes from the stripping foil according to the closed-orbit shift due to acceleration. In this scheme, it is important to minimize the number of foil hitting, which causes emittance growth and foil heating. In this paper, the rf capture is studied by means of simulation.

MOPC161	Challenges for the Low Level RF Design for ESS	cavity, LLRF, controls, klystron	460
	A.J. Johansson Lund University, Lund, Sweden R. Zeng ESS, Lund, Sweden
	The European Spallation Source (ESS) is a planned neutron source to be built in Lund, Sweden, which is planned to produce the first neutrons in 2019. It will have an average beam power at the target of 5 MW, an average current along the Linac of 50 mA, and a pulse repetition rate and length of 20 Hz and 2 ms, respectively. The Linac will have around 200 LLRF stations employed to control a variety of RF cavities such as RFQ, DTL, spoke and elliptical superconducting cavities. The challenges on LLRF systems are mainly the high demands on energy efficiency on all parts of the facility, an operational goal of 95% availability of the facility and a comparably short time from start of final design to commissioning. Running with long pulses, high current and spoke cavities also brings new challenges on LLRF design. In this paper we will describe the consequences these challenges have on the LLRF system, and the proposed solutions and development projects that have started in order to reach these demands.

MOPC165	Digital Low Level RF Development at Daresbury Laboratory	cavity, controls, LLRF, beam-loading	469
	P.A. Corlett, L. Ma, A.J. Moss STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Digital LLRF development using Field Programmable Gate Arrays (FPGAs) is a new activity at Daresbury Laboratory. Using the LLRF4 development board, designed by Larry Doolittle of Lawrence Berkeley National Laboratory, a full featured control system incorporating fast feedback loops and a feed-forward system has been developed for use on the ALICE (Accelerators and Lasers in Combined Experiments) energy recovery linac. Technical details of the system are presented, along with experimental measurements.

MOPC166	Low RF Control Feedback and IQ Vector Modulator Compensation Functions	controls, gun, feedback, coupling	472
	M.G. Fedurin, R. Malone, V. Yakimenko BNL, Upton, Long Island, New York, USA
	IQ vector modulator is key element of the gun and linac RF control circuits at Accelerator Test Facility at Brookhaven National Laboratory. IQ modulator calibration procedure was developed to find proper compensation functions in the conversion algorithm to minimize phase-amplitude coupling and setting-reading errors: rms(A_set - A_read )= 0.03dB, rms(Phi_set - Phi_read) = 0.3 deg. Since stabilization of the RF phase and amplitude is become critical for many experiments the slow feedback was developed and applied as well to significantly compensate drifts in RF system.

MOPO023	Laser-based Alignment System at the KEKB Injector Linac	laser, alignment, vacuum, injection	529
	M. Satoh, N. Iida, T. Suwada KEK, Ibaraki, Japan K. Minoshima, S. Telada AIST, Tsukuba, Japan
	A laser-based alignment system is under development at the 500-m-long KEKB injector linac. The original system was designed and constructed more than thirty-years ago, and thus, we are revisiting our alignment system because the previous alignment system has become too obsolete. The new alignment system is again strongly required for the next generation SuperKEKB project. The new laser alignment system is similar to the previous one, which comprises a helium-neon laser and quadrant photodetectors installed in vacuum light pipes. A girder displacement of the accelerating structure can be precisely measured in the direction of the laser-ray trace, where the laser light must stably propagate up to 500-m downstream without any orbital and beam-size fluctuation. We tested the laser-ray propagation and the stability along a 100-m-long beam line under a vacuum condition of 0.1-1 Torr. In this paper, we will report the system description and test results in detail.

MOPO025	Experimental Study on New Laser-based Alignment System utilizing a Sequential Three-point Method at the KEKB Injector Linac	laser, alignment, focusing, factory	532
	T. Suwada, M. Satoh KEK, Ibaraki, Japan K. Minoshima, S. Terada AIST, Tsukuba, Japan
	A new laser-based alignment system is under development in order to precisely align accelerator components along an ideal straight line at the 600-m-long KEKB injector linac. A well-known sequential three-point method with Fresnel lenses and a CCD camera is revisited in a preliminary design of the new alignment system. The new alignment system is strongly required in order to stably accelerate high-brightness electron and positron beams with high bunch charges and also to keep the beam stability with higher quality towards the Super B-factory at KEK. A new laser optics has been developed and the laser propagation characteristics has been systematically investigated at a 200-m-long straight section at atmospheric pressure. In this report, the preliminary experimental results are reported along with the basic design of the new laser-based alignment system.

MOPO030	Theoretical and Practical Feasibility Demonstration of a Micrometric Remotely Controlled Pre-alignment System for the CLIC Linear Collider	alignment, simulation, target, controls	547
	H. Mainaud Durand, M. Anastasopoulos, N.C. Chritin, J. Kemppinen, M. Sosin, S. griffet CERN, Geneva, Switzerland T. Touzé ENSTA, Brest, France
	The active pre-alignment of the Compact Linear Collider (CLIC) is one of the key points of the project: the components must be pre-aligned w.r.t. to a straight line within a few microns over a sliding window of 200 m, along the two linacs of 20 km each. The proposed solution consists of stretched wires of more than 200 m, overlapping over half of their length, which will be the reference of alignment. Wire Positioning Sensors (WPS), coupled to the supports to be pre-aligned, will perform precise and accurate measurements within a few microns, w.r.t. these wires. A micrometric fiducialisation of the components and a micrometric alignment of the components on common supports will make the strategy of pre-alignment complete. In this paper, the global strategy of active pre-alignment is detailed and illustrated by the latest results demonstrating the feasibility of the proposed solution.

MOPO041	Preliminary Testing of TPS Timing System	controls, gun, booster, EPICS	574
	C.Y. Wu, Y.-T. Chang, J. Chen, Y.-S. Cheng, P.C. Chiu, K.T. Hsu, K.H. Hu, C.H. Kuo, C.-Y. Liao NSRRC, Hsinchu, Taiwan
	The timing system of Taiwan Photon Source (TPS) provides synchronization for electron gun, modulators of linac, pulse magnet power supplies, booster power supply ramp, bucket addressing of storage ring, diagnostic equipments, beamline gating signal for top-up injection. The timing system utilizes a central event generator to generate events and distribute them over optic fiber network, and decodes them at the event receivers. The system supports uplink functionality which will be used for the fast interlock system to distribute signals like beam dump and post-mortem trigger. The timing system has now been in operation for Linac of TPS. This paper presents prototype for the timing system of TPS.

MOPS019	High Intensity Longitudinal Dynamics Studies for Higher Energy Injection into the ISIS Synchrotron	injection, simulation, bunching, space-charge	640
	R.E. Williamson, D.J. Adams, C.M. Warsop STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	ISIS is the world’s most productive pulsed neutron and muon source, at the Rutherford Appleton Laboratory in the UK. Operation is centred on a loss-limited 50 Hz proton synchrotron which accelerates 3·10¹³ protons per pulse from 70 MeV to 800 MeV, delivering a mean beam power of 0.2 MW. Present studies on ISIS upgrades are focussed on a new linac for higher energy injection into the existing ring, potentially increasing beam current through reduction in space charge and optimized injection. Studies assume injection of a chopped beam at 180 MeV and offer the possibility of beam powers in the 0.5 MW regime. A critical aspect of such an upgrade is the longitudinal dynamics, associated RF parameters, space charge levels and stringent requirements on beam loss. This paper outlines studies optimizing longitudinal parameters including key design requirements such as bunching factor and satisfying the Keil-Schnell-Boussard stability criterion throughout acceleration. Work developing and benchmarking the in-house longitudinal dynamics code used for these studies is also summarized.

MOPS026	Start-to-end Beam Dynamics Simulations for the Prototype Accelerator of the IFMIF/EVEDA Project	rfq, simulation, quadrupole, solenoid	655
	N. Chauvin CEA/IRFU, Gif-sur-Yvette, France M. Comunian INFN/LNL, Legnaro (PD), Italy O. Delferrière, R.D. Duperrier, R. Gobin, A. Mosnier, P.A.P. Nghiem, D. Uriot CEA/DSM/IRFU, France C. Oliver CIEMAT, Madrid, Spain
	The EVEDA (Engineering Validation and Engineering Design Activities) phase of the IFMIF (International Fusion Materials Irradiation Facility) project consists in building, testing and operating a 125 mA/9 MeV prototype accelerator in Rokkasho-Mura (Japan). Because of high beam intensity and power, the different sections of the accelerator (injector, RFQ, MEBT, Superconducting Radio-Frequency linac and HEBT) have been optimized with the twofold objective of minimizing losses along the machine and keeping a good beam quality. Extensive start-to-end multi-particles simulations have been performed to validate the prototype accelerator design. A Monte Carlo error analysis has been carried out to study the effects of misalignments and field variations. In this paper, the results of theses beam dynamics simulations, in terms of beam emittance, halo formation and beam losses, are presented.

MOPS027	Stability Charts for the IFMIF SRF-Linac	emittance, resonance, SRF, space-charge	658
	W. Simeoni, N. Chauvin CEA/IRFU, Gif-sur-Yvette, France A. Mosnier, P.A.P. Nghiem, D. Uriot CEA/DSM/IRFU, France
	Among the most recent projects, the IFMIF-EVEDA accelerators break the record of high intensity, leading to a multi-MW beam power at relatively low energy. The concern for such accelerated beams is the predominance of the self-field energy upon the beam energy. In these conditions, the space charge effect is at its maximum, which triggers different nonlinear mechanisms implying emittance growth, halo formation and sudden particle lost. In this proceeding we show the stability charts constructed for the IFMIF SRF-Linac, with which are identified the collective space charge resonances responsible of transverse-longitudinal emittance exchange and emittance growth.

MOPS028	An Ion Beam Matching to a Linac Accelerating-focusing Channel	rfq, ion, emittance, simulation	661
	A. Orzhekhovskaya, W.A. Barth, G. Clemente, L.A. Dahl, P. Gerhard, L. Groening, M. Kaiser, M.T. Maier, S. Mickat, B. Schlitt, H. Vormann, S.G. Yaramyshev GSI, Darmstadt, Germany U. Ratzinger IAP, Frankfurt am Main, Germany
	Funding: Work supported by HIC for FAIR A modern linear accelerator of ions is a long chain of different accelerating-focusing structures. The design of new linacs, as well as an upgrade and optimization of operating facilities, requires precise and reliable beam matching with the subsequent sections. Proper matching of the beam to the channel allows to improve the performance of the whole linac and to reduce the specific costs. Additionally it helps to avoide particle loss in high energy high intensity linacs. Generally a matching algorithm combines precisely measured or calculated accelerating-focusing external fields and experimentally obtained details of the beam parameters with an advanced code for beam dynamics simulations including space charge effects. Experimental results are introduced into a code as input data. The described algorithm has already been successfully implemented for several GSI projects: an upgrade of the GSI heavy ion linac UNILAC, an ion linac for the cancer therapy, the proton linac for the FAIR facility, a facility for laser acceleration of ions and others. Measured data and results of beam dynamics simulations leading to an achieved improvement of the linac performance are presented.

MOPS030	Beam Dynamics of the FRANZ Bunch Compressor using Realistic Fields with a Focus on the Rebuncher Cavities	cavity, dipole, simulation, focusing	667
	D. Noll, L.P. Chau, M. Droba, O. Meusel, H. Podlech, U. Ratzinger, C. Wiesner IAP, Frankfurt am Main, Germany
	Funding: Work supported by HIC for FAIR. The ARMADILLO bunch compressor currently being designed at IAP is capable of reaching a longitudinal pulse compression ratio of 45 for proton beams of 150 mA at 2 MeV. It will provide one nanosecond proton pulses with a peak current of 7.7 A. The system guides nine linacμbunches deflected by a 5 MHz rf kicker and uses four dipole magnets - two homogeneous and two with field gradients - to merge them on the target. For longitudinal focusing and an energy variation of ±200 keV two multitrack rf cavities are included. ARMADILLO will be installed at the end of the Frankfurt Neutron Source FRANZ making use of the unique 250 kHz time structure. This contribution will provide an overview of the layout of the system as well as recent advances in component design and beam dynamics of the compressor.

MOPS033	Beam Dynamics Studies on the 100 MeV/100 kW Electron Linear Accelerator for NSC KIPT Neutron Source	electron, dipole, gun, simulation	673
	S. Pei, Y.L. Chi, M. Hou, W.B. Liu, G. Pei, S.H. Wang, Z.S. Zhou IHEP Beijing, Beijing, People's Republic of China N. Aizatsky, I.M. Karnaukhov, V.A. Kushnir, V. Mitrochenco, A.Y. Zelinsky NSC/KIPT, Kharkov, Ukraine
	We designed one 100MeV/100kW electron linear accelerator for NSC KIPT, which will be used to drive a neutron source on the base of subcritical assembly. Beam dynamics studies has been conducted to reach the design requirement (E=100MeV, P=100kW, dE/E<1% for 99% particles). In this paper, we will present the progress of the design and dynamics simulation results. For high intensity and long beam pulse linear accelerators, BBU effect is one big issue; special care has been taken in the accelerating structure design. To satisfy the energy spread requirement at the linac exit, the particles with large energy difference from the synchronous particle should be eliminated at low energy stage to ease the design of the collimation system and radiation shielding. A dispersion free chicane with 4 bending magnets is introduced at the downstream of the 1st accelerating section; the unwanted particles will be collimated there.

MOPS035	Energy Spreads by Transient Beam Loading Effect in Pulsed RF Linac	gun, electron, bunching, beam-loading	679
	S.H. Kim, M.-H. Cho, G. Ha, H.R. Yang POSTECH, Pohang, Kyungbuk, Republic of Korea W. Namkung, S.J. Park PAL, Pohang, Kyungbuk, Republic of Korea J.-S. Oh NFRI, Daejon, Republic of Korea
	Funding: Work partly supported by KAPRA and POSTECH Physics BK21 Program RF linacs for high power beams are operated in the fully beam-loaded condition for the power efficiency. In this condition, temporal energy spreads are induced by the transient beam loading effect. Irradiation sources require the beam energy of less than 10 MeV to prevent undesirable neutron production. In order to maximize the beam power and maintain the beam energy in a safe value, we need to suppress the temporal energy spreads. In an L-band traveling-wave linac for irradiation sources, the high energy electrons are suppressed by the beam current modulation with the RF power modulation. As a result, the average beam energy and the corresponding beam power are improved by nearly 60% compared to the case without any modulations.

MOPS037	High Intensity Transient Beam Dynamic Study in Travelling Wave Electron Accelerators with Accounting of Beam Loading Effect	simulation, beam-loading, space-charge, electron	682
	S.M. Polozov, T.V. Bondarenko, E.S. Masunov, V.I. Rashchikov, A.V. Voronkov MEPhI, Moscow, Russia
	The beam loading effect is one of main problems limiting the beam current. The methods of beam dynamic simulation taking into account the beam loading effect were discussed previously. Simulation methods and the especial code version BEAMDULAD-BL was described in the paper. The beam loading effect was considered only for traveling wave linacs and for stationary beam only. Now it is important to study the beam dynamics of short current pulses, i.e. for transient process. We can consider only one beam bunch (or a packet of bunches) in a long external RF field pulse in stationary case. The beam radiation and wave fields can be calculated in the quasi-statically approximation. This approximation can not be used for transient mode. The methods of beam dynamics simulation will be discussed in this paper for transient mode. New code version BEAMDULAC-BLNS will be described. The simple test simulations will be carried out. A.V. Voronkov et al., "Beam Loading Effect of High Current Trawling Wave Accelerator Dynamic Study", Proc. of IPAC’10, Kyoto, Japan, TUPEA012, p. 1348 (2010).

MOPS038	3D Beam Dynamic Simulation in Heavy Ion Superconducting Drift Tube Linac	cavity, simulation, focusing, ion	685
	A.V. Samoshin, S.M. Polozov MEPhI, Moscow, Russia
	The superconducting (SC) linac conventionally consists of some different classes of the identical cavities. Each cavity is based on a SC structure with a high accelerating gradient. The low charge state beams require stronger transverse focusing. This focusing can be reached with the help of SC solenoid lenses. In this paper beam dynamics simulation obtain by smooth approximation and full field. Traditionally only the Coulomb field is taken into account for low energy beams. In this paper the computer simulation of heavy ion beam dynamics in superconducting (SC) linac will carried out by means of the "particle-in-cell" method. Simulation results will present.

MOPS040	Intra-Bunch Energy Spread of Electrons in Powerful RF Linacs for Nuclear Physics Research*	target, electron, HOM, simulation	691
	V.V. Mytrochenko, M.I. Ayzatskiy, V.A. Kushnir, A. Opanasenko, S.A. Perezhogin, V.L. Uvarov NSC/KIPT, Kharkov, Ukraine
	Funding: Ukrainian State program of fundamental and applied studies on the use of nuclear materials, nuclear and radiation technologies in the fields of economics (YaMRT project No. 826/35) There are some particles in RF electron linacs with energy that may be significantly different from that of particles within a core of the bunch. Loss of these particles at average beam power of tens of kilowatts can cause radiation and thermal problems. Filtration of such particles during the initial stage of acceleration, at energies below the threshold of photonuclear reactions, is important. The paper analyzes several ways to perform such type of filtration in the injector part of a powerful electron linac using a RF chopper or magnetic systems.

MOPS047	Studies of Transverse Single-pass Beam Breakup in E-Linac	HOM, cavity, dipole, emittance	706
	D. Kaltchev, R.A. Baartman, Y.-C. Chao, P. Kolb, S.R. Koscielniak, L. Merminga, A.K. Mitra, V. Zvyagintsev TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
	Time-domain simulations of single-pass transverse beam-breakup (BBU) effects in E-linac are described. We use dipole-HOM parameters for the 9-cell cavity obtained with Particle Studio to evaluate the rms bunch orbit offsets at linac exit. Finding the multi-bunch orbit contribution to machine emittance as a function of the average beam current allows to evaluate the performance of two cavity models for two different modes of machine operation.

MOPS051	Modeling of the Beam Break Up Instability for BERLinPro*	cavity, optics, solenoid, HOM	718
	Y. Petenev, A.V. Bondarenko, A.N. Matveenko HZB, Berlin, Germany
	Following funding approval late 2010, Helmholtz-Zentrum Berlin officially started Jan. 2011 the design and construction of the Berlin Energy Recovery Linac Project BERLinPro. The initial goal of this compact ERL is to develop the ERL accelerator physics and technology required to accelerate a high-current low emittance beam. In this work the threshold current of the Beam Break Up (BBU) instability was calculated for the BERLinPro. The comparison of two 100 MeV linacs based on different type of superconducting cavities is made. Different methods of BBU suppression are investigated (e.g. the influence of solenoid, pseudo-reflector and quadruple triplets in the linac structure on the BBU threshold).

MOPS058	KEKB Linac Wakefield Studies of Comparing Theoretical Calculation, Simulation and Experimental Measurement*	emittance, wakefield, injection, simulation	739
	L. Zang, N. Iida, Y. Ogawa, M. Satoh, M. Yoshida, D.M. Zhou KEK, Ibaraki, Japan
	For superKEKB, in order to achieve aiming luminosity machine need to run with a nano-beam scheme so that a small beam emittance is critical important. During the beam propagation, the short-range wake field in the accelerating structure will cause the beam instability and emittance growth. In practical, injecting beam with certain offset could compensate wakfield. And beam emittance could be measured by tuning the quadruple known as quadscan method. In this paper, wakefield theoretical calculation, simulation results will be presented. And then the wakefield impact to beam emittance and wakefield compensation will be discussed. Finally, we will show the comparison of the results getting from theoretical calculation and experimental measurement.

MOPS076	Long Range Wakefields in the SwissFEL C-band Linac	wakefield, HOM, simulation, impedance	781
	A. Citterio, M. Aiba, R. Zennaro PSI, Villigen, Switzerland
	The SwissFEL main linac consists of more than hundred constant gradient C-band accelerating structures which boost the beam energy from 410 MeV at the injector to the final nominal energy of 5.8 GeV. With a repetition rate of 100 Hz, two bunches per pulse can be accelerated with a spacing of 28 ns to feed simultaneously two different FEL arms. Rising of the long range wakefields, both longitudinal and transverse, could affect this multibunch operation, causing degenerative effects on the quality of the second bunch. A direct computation of the longitudinal and transverse wakes by means of time domain simulations is compared with a model based on the computation of the dispersion curves of the wake modes by frequency domain simulations. A good agreement is obtained for both the synchronous frequency and impedance of all the main modes contributing to the wakefields. Moreover, the total longitudinal wake at 28 ns is below the thighter tolerances required by the beam dynamics, so that neither Higher Order Modes (HOMs) either beam loading require compensation. The effects on the beam of the long range transverse wakefields are also negligeable. R. Ganter et al, SwissFEL CDR, PSI report n. 10-04; http://www.psi.ch/swissfel/CurrentSwissFELPublicationsEN/SwissFEL_CDR_{_}v19₀3.03.11-small.pdf

MOPS082	Some Considerations on the Choice of Frequency and Geometrical Beta in High Power Proton Linacs in the Context of Higher Order Modes	cavity, HOM, simulation, proton	793
	M. Schuh, F. Gerigk CERN, Geneva, Switzerland M. Schuh MPI-K, Heidelberg, Germany C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Several high power superconducting (SC) proton linear accelerators are currently in the design stage around the world, such as for example the European Spallation Source (ESS) in Lund, Project X at Fermilab, the European ADS demonstrator MYRRAH in Mol and the Superconducting Proton linac (SPL) at CERN. In this contribution, the influence of Higher Order Modes (HOMs) in elliptical SC cavities is discussed as a function of the operation frequency, the number of cells and the geometrical beta of the cavity. Based on cavity design data beam dynamics simulations are executed for different linac layouts to quantify the influence of HOMs.

MOPS085	Wakefield Calculations for the LCLS in Multibunch Operation*	dipole, injection, HOM, FEL	802
	K.L.F. Bane SLAC, Menlo Park, California, USA
	Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515. Normally the Linac Coherent Light Source (LCLS) operates in single-bunch mode, sending a bunch of up to 250 pC charge at 120 Hz through the linac and the undulator, and the resulting FEL radiation into one of the experimental hutches. With two bunches per rf pulse, each pulse could feed either two experiments or one experiment in a pump-probe type configuration. Two-bunch FEL operation has already been briefly tested at the LCLS, and works reasonably well, although not yet routinely. In this report we study the longitudinal and transverse long-range (bunch-to-bunch) wakefields of the linacs and their effects on LCLS performance in two-bunch mode. The longitudinal wake changes the average energy and chirp at the second bunch, and the transverse wake misaligns the second bunch (in transverse phase space) in the presence of e.g. transverse injection jitter or quad misalignments. Finally, we extend the study to consider the LCLS with trains of up to 20 bunches per rf pulse. F.-J. Decker et al, "A demonstration of multi-bunch operation in the LCLS," Proceedings of FEL2010, Malmoe, Sweden, p. 467.

MOPZ009	The Muon Linac for the International Design Study for the Neutrino Factory	cavity, cryomodule, factory, lattice	838
	A. Kurup, M. Aslaninejad, C. Bonţoiu, J.K. Pozimski Imperial College of Science and Technology, Department of Physics, London, United Kingdom K.B. Beard Muons, Inc, Batavia, USA S.A. Bogacz, V.S. Morozov JLAB, Newport News, Virginia, USA
	The first stage of muon acceleration in the Neutrino Factory utilises a superconducting linac to accelerate muons from 244 MeV to 900 MeV. The linac is split into three types of cryomodules with decreasing magnetic fields and increasing amounts of RF voltage but with the design of the superconducting solenoid and RF cavities being the same for all cryomodules. The current status of the muon linac for the International Design Study for the Neutrino Factory will be presented including a final lattice design of the linac; electromagnetic simulations; and a preliminary cost estimate.

MOPZ029	Aperture Windows in High-Gradient Cavities for Accelerating Low-Energy Muons	cavity, septum, target, vacuum	862
	S.S. Kurennoy, A.J. Jason, W.M. Tuzel LANL, Los Alamos, New Mexico, USA
	A high-gradient linear accelerator for accelerating low-energy muons and pions in a strong solenoidal magnetic field has been proposed for homeland defense and industrial applications. The acceleration starts immediately after collection of pions from a target in a solenoidal magnetic field and brings muons to a kinetic energy of about 200 MeV over a distance of the order of 10 m. At this energy, both ionization cooling of the muon beam and its further acceleration become feasible. A normal-conducting linac with external-solenoid focusing can provide the required large beam acceptances. The linac consists of independently fed zero-mode (TM010) RF cavities with wide beam apertures closed by thin conducting windows. The high gradients lead to significant heat deposition on the aperture windows. Here we explore options for the edge-cooled thin windows in the zero-mode cavities. Electromagnetic and thermal-stress computations are complemented by thermal-test experiments to select the best solution for the aperture windows. S.S. Kurennoy, A.J. Jason, H. Miyadera, “Large-Acceptance Linac for Accelerating Low-Energy Muons,” Proc. of IPAC10, p. 3518 (2010).

MOPZ031	Multipass Muon RLA Return Arcs based on Linear Combined-function Magnets	dipole, quadrupole, optics, lattice	868
	V.S. Morozov, S.A. Bogacz, Y. Roblin JLAB, Newport News, Virginia, USA K.B. Beard Muons, Inc, Batavia, USA
	Funding: Supported in part by US DOE STTR Grant DE-FG02-08ER86351. Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Recirculating Linear Accelerators (RLA) are an efficient way of accelerating short-lived muons to the multi-GeV energies required for Neutrino Factories and TeV energies required for Muon Colliders. In this paper we present a design of a two-pass RLA return arc based on linear combined function magnets, in which both charge muons with momenta different by a factor of two are transported through the same string of magnets. The arc is composed of 60°-bending symmetric super cells allowing for a simple arc geometry closing. By adjusting the dipole and quadrupole components of the combined-function magnets, each super cell is designed to be achromatic and to have zero initial and final periodic orbit offsets for both muon momenta. Such a design provides a greater compactness than, for instance, an FFAG lattice with its regular alternating bends and is expected to possess a large dynamic aperture characteristic of linear-field lattices.

TUXA01	Status and Challenges of the China Spallation Neutron Source	DTL, power-supply, rfq, dipole	889
	S. Fu, H. Chen, Y.W. Chen, Y.L. Chi, H. Dong, L. Dong, S.X. Fang, K.X. Huang, W. Kang, J. Li, L. Ma, H.F. Ouyang, H. Qu, H. Sun, J. Tang, C.H. Wang, Q.B. Wang, S. Wang, T.G. Xu, Z.X. Xu, X. Yin, C. Zhang, J. Zhang IHEP Beijing, Beijing, People's Republic of China
	The accelerator complex of China Spallation Neutron Source (CSNS) mainly consists of an H⁻ linac of 80 MeV and a rapid-cycling synchrotron of 1.6 GeV. It operates at 25 Hz repetition rate with an initial proton beam power of 100 kW and is upgradeable to 500kW. The project will start construction in the middle of 2011 with a construction period of 6.5 years. The CSNS accelerator is the first large-scale, high-power accelerator project to be constructed in China and thus we are facing a lot of challenges. This paper presents the current status of CSNS project and summarizes the technology development during the past several years.
	Slides TUXA01 [3.444 MB]

TUOAA01	The EUROnu Project: A High Intensity Neutrino Oscillation Facility in Europe	target, factory, proton, acceleration	894
	T.R. Edgecock STFC/RAL, Chilton, Didcot, Oxon, United Kingdom E.H.M. Wildner CERN, Geneva, Switzerland
	EUROnu is a European Commission funded FP7 Design Study investigating three possible options for a future high intensity neutrino oscillation facility in Europe. These options are a CERN to Frejus Super-Beam, a Neutrino Factory and a Beta Beam. The aims of the project are to undertake the crucial R&D on each of the accelerator facilities and determine their performance and relative cost, including the baseline detectors for each facility. A comparison will then be made and the results reported to the CERN Council as part of the CERN Strategy Review.
	Slides TUOAA01 [7.638 MB]

TUOAA03	The Linac4 Project at CERN	DTL, cavity, rfq, klystron	900
	M. Vretenar, L. Arnaudon, P. Baudrenghien, C. Bertone, Y. Body, J.C. Broere, O. Brunner, M.C.L. Buzio, C. Carli, F. Caspers, J.-P. Corso, J. Coupard, A. Dallocchio, N. Dos Santos, R. Garoby, F. Gerigk, L. Hammouti, K. Hanke, M.A. Jones, I. Kozsar, J.-B. Lallement, J. Lettry, A.M. Lombardi, L.A. Lopez Hernandez, C. Maglioni, S.J. Mathot, S. Maury, B. Mikulec, D. Nisbet, C. Noels, M.M. Paoluzzi, B. Puccio, U. Raich, S. Ramberger, C. Rossi, N. Schwerg, R. Scrivens, G. Vandoni, J. Vollaire, S. Weisz, Th. Zickler CERN, Geneva, Switzerland
	As the first step of a long-term programme aiming at an increase in the LHC luminosity, CERN is building a new 160 MeV H⁻ linear accelerator, Linac4, to replace the ageing 50 MeV Linac2 as injector to the Proton-Synchrotron Booster (PSB). Linac4 is an 86-m long normal-conducting linac made of an H⁻ source, a Radio Frequency Quadrupole (RFQ), a chopping line and a sequence of three accelerating structures: a Drift-Tube Linac (DTL), a Cell-Coupled DTL (CCDTL) and a Pi-Mode Structure (PIMS). The civil engineering has been recently completed, and construction of the main accelerator components has started with the support of a network of international collaborations. The low-energy section up to 3 MeV including a 3-m long 352 MHz RFQ entirely built at CERN is in the final construction phase and is being installed on a dedicated test stand. The present schedule foresees beam commissioning of the accelerator in the new tunnel in 2013/14; the moment of connection of the new linac to the CERN accelerator chain will depend on the LHC schedule for long shut-downs.
	Slides TUOAA03 [10.347 MB]

TUYB03	CLIC Conceptual Design and CTF3 Results	emittance, target, damping, luminosity	961
	D. Schulte CERN, Geneva, Switzerland
	An international collaboration is carrying out an extensive R&D programme to prepare CLIC, a multi-TeV electron-positron collider. In this concept, the colliding beams will be accelerated in very high gradient normal conducting 12 GHz accelerating structures. The necessary RF power is extracted from a high-current, low-energy drive beam that runs parallel to the colliding beams and is generated in a central complex. This year the collaboration will produce a conceptual design report to establish the feasibility of the technology. The CLIC concept will be introduced and the status of key studies of critical issues will be reviewed. A focus will be on the CLIC Test Facility 3 (CTF3), which is a test facility to produce and use high current a drive beam.
	Slides TUYB03 [13.204 MB]

TUZB01	Superconducting RF Technology for Proton and Ion Accelerators	cavity, cryomodule, SRF, proton	966
	G. Devanz CEA/DSM/IRFU, France
	The worldwide status of superconducting RF cavities and cryomodules for low velocity ion and proton particles is reviewed, with emphasis on the construction and tests of prototypes. A number of different multicell structures at a range of operating frequencies have been successfully realized. This review will cover the progress of several facilities under construction or being proposed: Spiral2, IFMIF-EVEDA, SPL, ESS, FRIB and ADS drivers.
	Slides TUZB01 [10.630 MB]

TUPC008	CLIC Two-Beam Module for the CLIC Conceptual Design and Related Experimental Program	alignment, vacuum, quadrupole, RF-structure	1003
	A. Samoshkin, D. Gudkov, A. Solodko JINR, Dubna, Moscow Region, Russia G. Riddone CERN, Geneva, Switzerland
	The Compact LInear Collider (CLIC), being studied at CERN, involves the design and integration of many different technical systems, tightly bound and influencing each other. For the construction of two main linacs it has been decided to proceed with a modular design, and repetitive two-beam modules of a few types were defined. The modules consist of micro-precision components operating under ultra-high vacuum as required by the beam physics. For the CLIC Conceptual Design Report, the development and system integration is mainly focused on the most complex module type containing the highest number of components and technical systems. For proving the proper functioning of the needed technical systems and confirming their feasibility it has been decided to build four prototype modules and test them without beam. In addition, three modules have to be produced in parallel for tests in the CLIC Experimental Area with beam. This paper is focused on the design of the different technical systems and integration issues of the two-beam module. The experimental program for the prototype modules is also recalled.

TUPC010	Status of the Manufacturing of Accelerating Structures for LINACs	vacuum, controls, extraction, laser	1009
	F.M. Mirapeix, J. Añel, J. Castillo, A. Ortiz HTS, Mendaro, Spain X. Aldalur, J. Amores, A. Urzainki DMP, Mendaro, Spain
	Funding: HTS, DMP, ZEHATZ, CERN Particle accelerators need ongoing development in the state of the art of the field: high-quality manufacturing of accelerating structures, PETS, but also drift tubes, bunchers, high-power couplers, alignment systems, precision test stands, etc. They also require engineering projects in the range of mechatronics, thermodynamics, microwaves, ultra high vacuum, cryogenics, joining techniques, high precision manufacturing, 3D high precision scanning, etc. HTS together with DMP are actually working on all this fronts. In this paper, the actual status of the manufacturing capabilities concerning some accelerating structures will be described.

TUPC012	Fabrication and Validation of the Prototype Supporting System for the CLIC Two-beam Modules	alignment, RF-structure, radiation, tandem-accelerator	1015
	N. Gazis, G. Riddone, S. griffet CERN, Geneva, Switzerland A. Samoshkin JINR, Dubna, Moscow Region, Russia
	The Compact LInear Collider (CLIC), currently under study at CERN, aims at the development of a Multi-TeV e⁺ e^- collider and relies upon a novel two-beam acceleration concept. In the two-beam acceleration, the Radio Frequency (RF) power is extracted from a low energy but high-intensity particle beam, and it is transferred to a parallel high energy main beam. The two-beam modules are the smallest repetitive units which compose the two linacs. The RF structures are the most precise components and they are mounted and aligned on specially developed supporting system, which provides stability and quick re-positioning. The supporting girders have stringent stiffness and damping requirements, imposed by beam physics requirements. In addition, several constraints, such as allocated space and weight limitation have to be taken into consideration. This paper describes different girder configurations following various fabrication techniques and materials. Extensive qualification measurements have been performed on the first prototype units, and the main results are also presented.

TUPC013	Simulation of Phase Stability at the Flat Top of the CLIC Drive Beam	simulation, luminosity, kicker, collider	1018
	A. Gerbershagen, D. Schulte CERN, Geneva, Switzerland P. Burrows Oxford University, Physics Department, Oxford, Oxon, United Kingdom
	Funding: University of Oxford The drive beam phase stability is one of the critical issues of the Compact Linear Collider (CLIC). In this paper the generation and propagation of drive beam phase errors is studied for effects that vary during the drive beam pulse. This includes the influence of drive beam current and phase errors as well as of drive beam accelerator RF phase and amplitude errors on the drive beam phase after the compressor chicanes and the analysis of the propagation of these errors through the drive beam combination scheme. The impact of the imperfections on the main beam is studied including the possible correction with help of a feedforward system.

TUPC017	Civil Engineering Studies for Major Projects after LHC	collider, interaction-region, civil-engineering, site	1030
	J.A. Osborne, F.J. Magnin, E. Perez-Duenas CERN, Geneva, Switzerland
	CERN civil engineers are heavily involved in studying several major projects to succeed/complement the LHC. Infrastructure works typically represent one third of the cost of major physics projects, so it's critical that the construction costs are well understood from the conceptual stage. For example, CERN are studying infrastructure requirements for the Linear Collider (CLIC & ILC) and the LHeC projects. This poster presents some of the key civil engineering challenges faced in such large scale projects.

TUPC018	Progress on Modelling of the Thermo-Mechanical Behavior of the CLIC Two-Beam Module	vacuum, RF-structure, simulation, collider	1033
	R.J. Raatikainen, K. Osterberg HIP, University of Helsinki, Finland T.O. Niinikoski, G. Riddone CERN, Geneva, Switzerland
	The luminosity goal of the CLIC collider, currently under study, imposes micrometer mechanical stability of the 2-m long two-beam modules, the shortest repetitive elements of the main linacs. These modules will be exposed to variable high power dissipation during operation resulting in mechanical distortions in and between module components. The stability of the CLIC module will be tested in laboratory conditions at CERN in a full-scale prototype module. In this paper, the FEA model developed for CLIC prototype module is described. The thermal and structural results for the new module configuration are presented considering the thermo-mechanical behavior of the CLIC collider in its primary operation modes. These results will be compared to the laboratory measurements to be done during 2011 and 2012 with the full-scale prototype module. The experimental results will allow for better understanding of the module behaviour and they will be propagated back to the present thermo-mechanical model.

TUPC020	Alignment and Wake Field Issues in the CLIC RTML	emittance, lattice, wakefield, cavity	1039
	F. Stulle, S. Döbert, A. Latina, D. Schulte CERN, Geneva, Switzerland
	At main linac injection the particle beams need to stay within tight tolerances for the transverse emittances and the pointing stability. We study how these tolerances influence alignment requirements for the RTML components and the stability of the beams entering the RTML. An emphasize is put on the booster linac and the RF cavities of the second bunch compression stage since short and long range wake fields might strongly influence beam dynamics in these parts of the RTML.

TUPC021	The CLIC Feasibility Demonstration in CTF3	cavity, acceleration, electron, ion	1042
	P.K. Skowroński, J. Barranco, S. Bettoni, B. Constance, R. Corsini, A.E. Dabrowski, M. Divall Csatari, S. Döbert, A. Dubrovskiy, O. Kononenko, M. Olvegård, T. Persson, A. Rabiller, F. Tecker CERN, Geneva, Switzerland E. Adli University of Oslo, Oslo, Norway W. Farabolini CEA/DSM/IRFU, France R.L. Lillestol NTNU, Trondheim, Norway T. Muranaka, A. Palaia, R.J.M.Y. Ruber Uppsala University, Uppsala, Sweden
	The objective of the CLIC Test Facility CTF3 is to demonstrate the feasibility issues of the CLIC two-beam technology: the efficient generation of a very high current drive beam, used as the power source to accelerate the main beam to multi-TeV energies with gradient over 100MeV/m, stable drive beam deceleration over long distances. Results on successful beam acceleration with over 100 MeV/m energy gain are shown. Measurements of drive beam deceleration over a chain of Power Extraction Structures are presented. The achieved RF power levels, the stability of the power production and of the deceleration are discussed. Finally, we overview the remaining issues to be shown until the end of 2011.

TUPC022	Design of the CLIC Drive Beam Recombination Complex	emittance, injection, sextupole, synchrotron	1045
	J. Barranco, P.K. Skowroński, F. Tecker CERN, Geneva, Switzerland C. Biscari INFN/LNF, Frascati (Roma), Italy
	The CLIC Drive Beam Recombination Complex (DBRC) is designed to compress beam pulses from a current of 4.1 A to 100 A before using them to produce RF power in the deceleration lines. The beam is transported isochronously through a complex system consisting of a delay loop, two combiner rings and final turn around. The system is designed to preserve transverse and longitudinal emittances. During the optics design, chromaticity and non-linear dispersion were identified as the main single particle dynamics causes for transverse emittance increase. Different sextupole families are used to compensate these chromatic effects while keeping isochronicity. The bunch length is also adjusted to minimize coherent synchrotron radiation effects on bunch length, energy spread and transverse emittance. Finally, the injection scheme of the combiner rings was improved making the time variable bump created with help of the RF deflectors truly achromatic.

TUPC032	Beam Phase-Space Study for AREAL RF Photogun Linac	gun, emittance, space-charge, electron	1069
	B. Grigoryan, G.A. Amatuni, I.N. Margaryan, A.V. Tsakanian, V.M. Tsakanov, A. Vardanyan CANDLE, Yerevan, Armenia
	In order to produce high brightness electron beams with sub-picosecond bunch duration, the creation of Advanced Research Electron Accelerator Laboratory (AREAL) at CANDLE based on photocathode RF gun is under consideration. For several experimental setup purposes the linac will operate in single and multibunch modes with final beam energy 5-20 MeV and the bunch charge 10 100 pC. The study of beam phase space evolution along the linac is performed to optimize the beam main characteristics: emittance, bunch length and energy spread. The dependence of longitudinal and transverse distribution of electrons in photocathode region on RF cavity performances is analyzed.

TUPC033	Verifying the Single Bunch Capability of the New Injector at ELSA*	electron, gun, single-bunch, pick-up	1072
	S. Mey, O. Boldt, W. Hillert, N. Hofmann, F. Klarner, D. Krönung, A. Roth, M. Schedler ELSA, Bonn, Germany S. Aderhold DESY, Hamburg, Germany
	Funding: Funded by the DFG within the SFB / TR 16 and the Helmholtz Alliance HA 10¹ "Physics at the Terascale". In order to enhance the operating capabilities of the Bonn University Accelerator Facility, ELSA, a new injector is currently under commissioning. One of its main purpose is to allow a single pulse mode. The injector produces a single electron bunch with 1.5 A pulse current. Design and optimization of the injector have been performed with EGUN, PARMELA and numerical simulations based on the numerical integration of the paraxial equation. A 1 ns long pulse is produced by a thermionic electron source with 90 kV anode - cathode voltage, then compressed and pre-accelerated by a subsequent 500 MHz RF cavity and a four-cell travelling wave buncher. Finally, the bunch will be accelerated to 20 MeV by the main LINAC section. Measurements have been conducted concerning the resulting pulse length and pulse charge to confirm the predictions made by simulations and to investigate the efficiency of the injector system.

TUPC034	Design Studies on 100 MeV/100 kW Electron Linac for NSC KIPT Neutron Source on the Base of Subcritical Assembly Driven by Linac	electron, emittance, gun, target	1075
	Y.L. Chi, J. Cao, X.W. Dai, C.D. Deng, M. Hou, X.C. Kong, R.L. Liu, W.B. Liu, C. Ma, G. Pei, H. Song, S.H. Wang, G. Xu, J. Zhao, Z.S. Zhou IHEP Beijing, Beijing, People's Republic of China M.I. Ayzatskiy, I.M. Karnaukhov, V.A. Kushnir, V.V. Mytrochenko, A.Y. Zelinsky NSC/KIPT, Kharkov, Ukraine S. Pei IHEP Beijng, Beijing, People's Republic of China
	In NSC KIPT, Kharkov, Ukraine, a neutron source on the base of subcritical assembly driven by 100 MeV/100 kW electron linear accelerator is under design and development. To provide neutron flux value of about 1013 neutron/s the electron linear accelerator with 100 MeV beam and average beam power of 100 kW will be used. Construction and manufacture of the linear accelerator of such high beam intensity with low emittance and beam losses is a challenging task. In the report the project of the electron linear accelerator of the required beam energy and intensity is described. The accelerator structure and main technical solutions are presented. To overcome the BBU effect of this high average beam current, several effective measures are adopt, such as using constant gradient structure to spread the HOMs frequencies different cells, larger inner radius and shorter section length make the higher group velocity and optimize the structure geometry to keep the shunt impedance as good as possible. After the beam bunching system, a chicane is followed to chopper the beam to avoid the beam lost in the higher energy part.

TUPC038	A Low Energy Thermionic RF Gun Linac for Ultrashort Electron Beam	gun, electron, bunching, klystron	1081
	J.-Y. Hwang, J.H. Chen, W.K. Lau, A.P. Lee, T.H. Wu NSRRC, Hsinchu, Taiwan N.Y. Huang NTHU, Hsinchu, Taiwan
	A low energy test linac is being constructed at NSRRC for technological development of high brightness electron injector. It is a 29 MeV S-band linac that equipped with a high gradient thermionic cathode rf gun for generation of ultrashort relativistic electron beam by velocity bunching in the rf linac section located at downstream. High quality GHz-repetition-rate electron pulses of about 30 pC in bunch charge, pulse duration as short as 100 fsec can be produced from this test facility. It can be used as the driver for future light source experiments such as ultrafast head-on inverse Compton scattering (ICS) X-ray source and intense coherent THz free electron lasers.

TUPC042	First Beam to FACET	electron, positron, controls, vacuum	1093
	R.A. Erickson, C.I. Clarke, W.S. Colocho, F.-J. Decker, M.J. Hogan, S. Kalsi, N. Lipkowitz, J. Nelson, N. Phinney, P. Schuh, J. Sheppard, H. Smith, T.J. Smith, M. Stanek, J.L. Turner, J. Warren, S.P. Weathersby, U. Wienands, W. Wittmer, M. Woodley, G. Yocky SLAC, Menlo Park, California, USA
	Funding: This work was supported by the Department of Energy contract DE-AC02-76SF00515. The SLAC 3km linear electron accelerator has been reconfigured to provide a beam of electrons to the new FACET facility while simultaneously providing an electron beam to the Linac Coherent Light Source (LCLS). FACET is a new experimental facility constructed in the linac tunnel that can transport, compress, and focus electron bunches to support a variety of accelerator R&D experiments. In this paper, we describe our first experiences with the operation of the linac for this new facility.

TUPC045	Recirculating Electron Linacs (REL) for LHeC and eRHIC	electron, lattice, dipole, proton	1099
	D. Trbojevic, J. Beebe-Wang, Y. Hao, D. Kayran, V. Litvinenko, V. Ptitsyn, N. Tsoupas BNL, Upton, Long Island, New York, USA
	Funding: Work performed under a Contract Number DE-AC02-98CH10886 with the auspices of the US Department of Energy. We present a design of a CW Electron Recovery Linacs (ERL) for future electron hadron colliders eRHIC and LHeC. In eRHIC, a six-pass ERL would be installed in the existing tunnel of the present Relativistic Heavy Ion Collider (RHIC). The 5-30 GeV polarized electrons will collide with RHIC’s 50-250 (325) GeV polarized protons or 20-100 (130) GeV/u heavy ions. In LHeC a 3-pass 60 GeV CW ERL will produce polarized electrons for collisions with 7 TeV protons. After collision, electron beam energy is recovered and electrons are dumped at low energy. Two superconducting linacs are located in the two straight sections in both ERLs. The multiple arcs are made of Flexible Momentum Compaction lattice (FMC) allowing adjustable momentum compaction for electrons with different energies. The multiple arcs, placed above each other, are matched to the two linac’s straight sections with splitters and combiners.

TUPC054	LHeC ERL Design and Beam-dynamics Issues	optics, emittance, HOM, cavity	1120
	S.A. Bogacz, I. Shin JLAB, Newport News, Virginia, USA D. Schulte, F. Zimmermann CERN, Geneva, Switzerland
	We discuss machine and beam parameter choices for a Linac-Ring option of the Large Hadron electron Collider (LHeC) based on the LHC. With the total wall-plug power limited to 100 MW and a target current of about 6 mA the desired luminosity of 10³3 cm^-2 s^-1 can be reached, providing one exploits unique features of the Energy Recovery Linac (ERL). Here, we describe the overall layout of such ERL complex located on the LHC site. We present an optimized multi-pass linac optics enabling operation of the proposed 3-pass Recirculating Linear Accelerator (RLA) in the Energy Recovery mode. We also describe emittance preserving return arc optics architecture; including layout and optics of the arc switch-yard. Furthermore, we discuss importance of collective effects such as: beam breakup in the RLA, as well as ion accumulation, with design-integrated mitigation measures, and the electron-beam disruption in collision. Finally, a few open questions are highlighted.

TUPC066	Charged Particle Beam Profile Detector based on Yb-doped Optical Fibers	radiation, proton, ion, laser	1150
	C.S. Søndergaard Aarhus University Hospital, Aarhus, Denmark A. Baurichter, B.R. Nielsen Danfysik A/S, Jyllinge, Denmark G. Boudreault Rigshospitalet Copenhagen, PET and Cyclotron Unit, Copenhagen, Denmark K. Hansen, D.V. Madsen, J. Rasmussen, B.F. Skipper Aarhus School of Engineering, Aarhus, Denmark M. Kristensen Aarhus University, Aarhus, Denmark S.P. Møller ISA, Aarhus, Denmark A. Peters HIT, Heidelberg, Germany
	Funding: The Danish National Advanced Technology Foundation, contract # 002-2005-1 A radiation robust, high dynamic range beam profile detector based on scintillating fibers will be presented. The beam profile detector has been developed for particle therapy type ion beams of multiple hundreds MeV/n in the intensity range from 10⁵ to 10⁹ ions/s as a simple and less expensive replacement for MWPC based detectors. Scintillating fibers are typically based on doped polymers, which are sensitive to radiation damage. Here we report on the advantage of using silica optical fibers doped with rare-earth elements for the purpose of detecting ionizing radiation. Specifically, we find that ytterbium doped fibers generate a strong emission signal in the near-infrared from the Yb³⁺ state when penetrated by ionizing radiation, and that the emission has a high resistance against the accumulated dose in the fiber. We demonstrate the use of such fibers in a beam profile detector for charged particle beams in medical applications (radionuclide production and hadron therapy); more generally they are a promising alternative for prolonged used in ionizing radiation, such as accelerator diagnostics equipment or space applications.

TUPC070	SAFARI, an Optimized Beam Stop Device for High Intensity Beams at the SPIRAL2 Facility	beam-transport, neutron, beam-losses, vacuum	1162
	E. Schibler IN2P3 IPNL, Villeurbanne, France L. Perrot IPN, Orsay, France
	The SPIRAL2 facility at GANIL-Caen is now in its construction phase, with a project group including the participation of many French laboratories (CNRS, CEA) and international partners. The facility will be able to produce various accelerated beams at high intensities: 40 MeV Deuterons, 33 MeV Protons with intensity until 5mA and heavy ions with A/Q=3 up to 14.5MeV/u until 1mA current. We will present the final status of the 200kW beam stop located in the high energy beam transport lines. From the beam characteristics (HEBT line up to beam stop) and activation constraints, we studied and developed a complete design of a new high efficiency Beam Stop that has been nicknamed SAFARI (Système Arrêt Faisceau Adapté Rayons Intenses - Optimized Beam Stop Device for High Intensity Beams). Special focus will be done on the adequacy between beam dynamic and thermo-mechanical behavior. The Beam Stop shape marries to the beam characteristics in order to smooth for the best power density and improve thermo-mechanical behavior under nominal and critical beams. Optimization by various fluids studies and calculations led us to a new high efficiency counter-current water cooling system.

TUPC097	Status of Cold Cavity Beam Position Monitor for STF	cavity, cryomodule, vacuum, coupling	1236
	E.-S. Kim, A. Heo KNU, Deagu, Republic of Korea H. Hayano KEK, Ibaraki, Japan
	Cold cavity BPM was developed to meet high position resolution and bunch to bunch measurement time. It is designed based on re-entrant cavity and has Low-Q to achieve short signal decay time in L-band frequency with large aperture as 78mm. The beam test was performed to demonstrate position resolution at ATF main linac, which is operating with 1.6nC bunch charge, while BPM will be installed inside the ILC cyomodule with 3.2nC spacing 369ns like as ILC at STF. Stripline BPMs, ML2P and ML3P installed upstream and downstream of the BPM’s location respectively were used to predict its position. Reference cavity was optimized to use for synchronous detection. We had achieved ~340nm position resolution since position resolution was estimated due to limitation of system with noise, namely in case of ideal state. We will present configuration of beam test, procedure to measure position resolution and the result on the test. Furthermore, new design will be introduced to improve signal intensity and have heavy coupling.

TUPC099	New Measurements of Proton Beam Extinction at J-PARC	proton, injection, secondary-beams, vacuum	1242
	K. Yoshimura, Y. Hori, Y. Igarashi, S. Mihara, H. Nishiguchi, Y. Sato, M. Shimamoto, Y. Takeda, M. Uota KEK, Ibaraki, Japan M. Aoki, S. Hikida, H. Nakai Osaka University, Osaka, Japan Y. Hashimoto J-PARC, KEK & JAEA, Ibaraki-ken, Japan
	Proton beam extinction, defined as a residual to primary ratio of beam intensity, is one of the most important parameters to realize the future muon electron conversion experiment (COMET) proposed at J-PARC. To achieve the required extinction level of 10^-9, we started measuring extinction at main ring (MR) as its first step. According to the various measurements done at the different positions, empty RF buckets of RCS, which were considered to be swept away by the RF chopper, contained about 10^-7 ~ 10^-5 of the main beam pulse due to chopper inefficiency. We have developed a new beam monitor with improved performance for further studies at the abort line. In addition, we have started new measurements at the Hadron experimental hall by using slow-extracted beam. In this paper, we present recent results and future prospect of beam extinction measurements.

TUPC100	Longitudinal Beam Profile Measurement at J-PARC Separated Drift Tube Linac	beam-losses, cavity, simulation, injection	1245
	T. Maruta KEK/JAEA, Ibaraki-Ken, Japan M. Ikegami KEK, Ibaraki, Japan A. Miura, G.H. Wei JAEA/J-PARC, Tokai-mura, Japan H. Sako JAEA, Ibaraki-ken, Japan
	We measured longitudinal beam profile at Separated Drift Tube Linac (SDTL) injection part by scanning beam transmission and beamloss at the downstream of SDTL section by changing SDTL injection phase. As the beam goes to acceptance edge, part of the beam which is out of acceptance isn't accelerate and finally it is lost by hitting to beam duct. Thus beam transmission shows sliced bunch shape by acceptance edge, it is possible to reconstruct the beam bunch shape. The result shows about 60% wider profile in both phi and E direction against to design.

TUPC101	Generation of Multimode Quasi-monochromatic Terahertz	electron, radiation, gun, cathode	1248
	K. Kan, T. Kondoh, K. Norizawa, A. Ogata, J. Yang, Y. Yoshida ISIR, Osaka, Japan
	Generation of quasi-monochromatic terahertz (THz) using multimode Coherent Cherenkov Radiation (CCR) on the order of 0.1 THz was investigated. CCR was generated by a hollow dielectric tube covered by a metal and an electron bunch from a photocathode radio-frequency (RF) gun linac. The intensity and frequency of CCR were measured directly by a Michelson interferometer and a bolometer. The frequency spectra measured by the interferometer indicated sharp peaks close to frequencies of 0.09 THz and 0.14 THz, which corresponded to TM03 and TM04 modes, respectively, according to theoretical calculation for a tube with inner and outer radii of 5 mm and 7 mm. The maximum gain of TM03 mode due to the tube length was obtained as 1.5 dB/cm. The other higher modes, e. g. 0.36 THz (TM09) and 0.40 THz (TM010), were also observed from a 150 mm long tube at a bunch charge of 15 pC, which decreased space charge effect and the bunch length. Finally, a new method for bunch diagnostic based on multimode CCR was proposed. The bunch length was estimated to be 0.45 ps at a bunch charge of 5 pC with the intensity ratio of TM03 to TM09 mode.

TUPC102	Measurement of Beam Loss Tracks by Scintillating Fibers at J-PARC Linac	beam-losses, background, simulation, gun	1251
	H. Sako, T. Maruta, A. Miura JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	Highest beam loss in the J-PARC linac has been observed that the ACS (Annular-Coupled Structure linac) section. Since the observed beam loss is proportional to the residual gas pressure, the source of the beam loss is considered as H0 produced in an interaction of H⁻ beams with remnant gas. If this assumption is valid, H0 hits the beam duct and changes into H⁺ and escapes from the beam duct. We constructed scintillation fiber hodoscopes to detect H⁺s and eventually identify the particle species as H⁺. The hodoscopes are made of 4 planes of hodoscopes which consists of 16 scintillation fibers of 64mm long and with 4mmx4mm cross section. We installed the hodoscopes at the upstream part of the ACS section and measured beam loss. The results are shown in this paper.

TUPC104	Beam Loss Detected by Scintillation Monitor	beam-losses, cavity, simulation, hadron	1257
	A. Miura, K. Hasegawa, T. Maruta, N. Ouchi, H. Sako JAEA/J-PARC, Tokai-mura, Japan Z. Igarashi, M. Ikegami, T. Miyao KEK, Ibaraki, Japan
	Ar gas proportional BLMs have measured the beam loss through operations, but they are also sensitive to background noise of X-ray emitted from RF cavities. We have tried to measure the beam loss using scintillation monitors which would bring more accurate beam loss measurements with suppression of X-ray noise. We measured beam loss using scintillation beam loss monitors. Because this scintillation BLM is sensitive for low energy gamma-rays and fast neutrons, small signals from X-rays would be also detected. As the measurement results, a good signal to noise ratio is observed for the scintillation monitor with quite low sensitivity to the background X-ray. And many single events are observed in the intermediate pulse bunch with about 600 ns as pulse width. In addition, because we fabricated the filter and integrated circuit, total amount of X-ray noise can become smaller. We obtained the good performances of scintillation BLM with small effect of X-ray noise. This monitor can be used for beam loss measurement and a knob for tuning. Furthermore, because the detail structure can be detected, this monitor could be employed for another diagnostic device.

TUPC105	Improvement of Beam Current Monitor with High Tc Current Sensor and SQUID at the RIBF	ion, cyclotron, heavy-ion, ECR	1260
	T. Watanabe, N. Fukunishi, O. Kamigaito, M. Kase, Y. Sasaki RIKEN Nishina Center, Wako, Japan
	A highly sensitive beam current (position) monitor with a high Tc (Critical Temperature) current sensor and a SQUID (Superconducting QUantum Interference Device), that is the HTc-SQUID monitor, has been developed for the RIBF (RI Beam Factory) in RIKEN. The purpose of our work is to measure the DC of high-energy heavy-ion beams nondestructively in such a way that the beams are diagnosed in real time and the beam current extracted from the cyclotron can be recorded without interrupting the beam user's experiments. Both the HTc magnetic shield and the HTc current sensor were dip-coated by thin layer of Bi-Sr-Ca-Cu-O (2223-phase, Tc=10⁶ K) on 99.9 % MgO ceramic substrates. Unlike other existing facilities, all these HTS fabrications are cooled by a low-vibration pulse-tube refrigerator. These technologies enable us to downsize the system. As a result, 1 uA Xe beam intensity (50 MeV/u) was successfully measured with a 10⁰ nA resolution. From last year, aiming at the higher resolution, improvement of the new HTc current sensor with two turn coils has been started. We will report the present status and the measurement results of the HTc-SQUID monitor.

TUPC115	Application of Libera Brilliance Single Pass at NSRL Linac BPM System	brilliance, controls, pick-up, injection	1284
	J.Y. Zou, J. Fang, P. Lu, T.J. Ma, B.G. Sun, Y.L. Yang, Z.R. Zhou USTC/NSRL, Hefei, Anhui, People's Republic of China
	Libera Brilliance Single Pass is a digital beam position processor with capabilities of single pass position measurement. This device can be used on the stripline beam position monitor (BPM) of the linac and transfer lines on light sources as well as injector system for the FELs. The linac of Hefei light source (HLS) was equipped with 2 stripline beam position monitors, which will be increased to 20 BPMs after upgrading. The existing BPM electronics were the homemade electronics with logarithm detector. To enhance the functionality of the BPM system, the Libera Brilliance Single Pass is employed to replace the existing BPM electronics. The newly buying devices have made test of characterization. The mapping of stripline BPM is made on a workbench with Libera Brilliance Single Pass. The beam position is tested at linac using Libera Brilliance Single Pass. And the results of these measurement performed on Libera are reported to compared to measurements with the linac’s existing BPM electronics.

TUPC125	Test of the Front-end Electronics and Acquisition System for the LIPAC BPMs	EPICS, pick-up, controls, LLRF	1311
	D. Belver, I. Arredondo, P. Echevarria, J. Feuchtwanger, H. Hassanzadegan, M. del Campo ESS-Bilbao, Zamudio, Spain F.J. Bermejo Bilbao, Faculty of Science and Technology, Bilbao, Spain J.M. Carmona, A. Guirao, A. Ibarra, L.M. Martinez Fresno, I. Podadera CIEMAT, Madrid, Spain V. Etxebarria, J. Jugo, J. Portilla University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain N. Garmendia, L. Muguira ESS Bilbao, Bilbao, Spain
	Funding: Work partially supported by Spanish Ministry of Science and Innovation under project AIC10-A-000441 and ENE2009-11230. Non-interceptive Beam Position Monitors pickups (BPMs) will be installed along the beamlines of the IFMIF/EVEDA linear prototype accelerator (LIPAC) to measure the transverse beam position in the vacuum chamber in order to correct the dipolar and tilt errors. Depending on the location, the BPMs response must be optimized for a beam of 175 MHz bunch repetition, an energy range from 5 up to 9 MeV, a current between 0.1 and 125 mA and continuous and pulse operation. The requirements from beam dynamics for the BPMs are quite stringent, aiming for the position an accuracy below 100 μm and a resolution below 10 μm, and for the phase an accuracy below 2° and a resolution below 0.3°. To meet these specifications, the BPM electronics system developed by ESS-Bilbao has been adapted for its use with the BPMs of LIPAC. This electronics system is divided in an Analog Front-End unit, where the signals are conditioned and converted to baseband, and a Digital Unit to sample them and calculate the position and phase. The electronics system has been tested at CIEMAT with a wire test bench and a prototype BPM. In this contribution, the tests performed will be fully described and the results discussed.

TUPC130	Beam Test Performance of the Beam Position Monitors for the TBL Line of the CTF3 at CERN	pick-up, quadrupole, monitoring, beam-transport	1326
	J.J. García-Garrigós, C. Blanch Gutierrez, J.V. Civera, A. Faus-Golfe IFIC, Valencia, Spain S. Döbert CERN, Geneva, Switzerland
	Funding: Funding Agency: FPA2010-21456-C02-01 A series of Inductive Pick-Ups (IPU) for Beam Position Monitoring (BPM) with its associated electronics were designed, constructed and tested at IFIC. A full set of 16 BPMs, so called BPS units, were successfully installed in the Test Beam Line (TBL) of the CLIC Test Facility (CTF3) at CERN. In this paper we present the results of the beam test carried out on the BPS units of the TBL in order to determine their beam performances and check the specified operational requirements. We focus particularly on the position resolution parameter which is the BPS figure of merit according to TBL demands and is expected to reach the 5um resolution at maximum beam current (28A). The beam test results of the BPS units are also compared with the parameters from their previous characterization test at lab.

TUPC134	Phase Detection Electronics for CLIC	pick-up, controls, luminosity, linear-collider	1338
	A. Andersson CERN, Geneva, Switzerland
	The Compact Linear Collider (CLIC) requires very tight RF phase synchronisation in order to preserve high luminosity. The electronics required for processing the signals delivered from the phase pick-ups present a significant challenge. This paper discusses the strategy adopted to achieve a sufficiently accurate measurement of the phase. Performance measurements performed in the lab of some of the sub-systems are also presented.

TUPC139	Overview of the CLIC Beam Instrumentation	cavity, beam-losses, laser, instrumentation	1350
	T. Lefèvre CERN, Geneva, Switzerland
	Driven by beam dynamic considerations the Compact Linear Collider (CLIC) is expected to require extremely tight tolerances on most beam parameters. An important milestone was reached in 2011 with the completion of the CLIC conceptual design report. In this context the requirements for CLIC beam instrumentation has been reviewed and studied in detail for the whole accelerator complex with the aim of demonstrating feasibility. A preliminary choice has been made for every CLIC instrument, serving as a baseline scenario for the next phase of the project which will concentrate on the detailed design, engineering and test of CLIC devices. Whenever possible existing solutions have been studied, focusing on any improvements necessary to meet the CLIC performance criteria. When no such devices exists, or if cost considerations come into play, new technologies have been under study. Several prototypes are already well advanced and are currently under test. This paper presents an overview of CLIC beam instrumentation, the possible reach of their performance and an outlook on future developments.

TUPC165	DITANET - Investigations into Accelerator Beam Diagnostics	diagnostics, electron, instrumentation, extraction	1422
	C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom C.P. Welsch The University of Liverpool, Liverpool, United Kingdom
	Funding: Work supported by the EU under GA-PITN-215080. DITANET is a Marie Curie initial training network in beam diagnostics. The network members, universities, research centres and industry partners, are developing diagnostics methods for a wide range of existing or future particle accelerators, both for electron and for ion beams. This is achieved through a cohesive approach that allows for the exploitation of synergies, whilst promoting knowledge exchange between partners. In addition to its broad research program, the network organizes schools and topical workshops for the beam instrumentation and particle accelerator communities. This contribution gives an overview of the Network's research outcomes to date and summarizes past and future training activities.

TUPC171	2D Optical Streaking for Ultra-short Electron Beam Diagnostics	laser, electron, simulation, diagnostics	1437
	L. Wang, Y.T. Ding, Z. Huang SLAC, Menlo Park, California, USA
	We propose a novel approach to measure the short electron bunch profile at micrometer level. Low energy electrons generated during beam-gas ionization are simultaneously modulated by the transverse electric field of a circularly-polarized laser, and then they are collected at a down-stream screen where the angular modulation are converted to a circular shape there. The longitudinal bunch profile is simply represented by the angular distribution of the electrons on the screen. We only need to know the laser wavelength for calibration and there is no phase synchronization problem. Meanwhile the required laser power is also relatively low in this setup. Some simulations examples and resolution of this method will be discussed.

TUPO007	FLUTE, a Linac Based THz Source	radiation, gun, synchrotron, synchrotron-radiation	1458

Paper

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MOXAA01

ALBA Synchrotron Light Source Commissioning

storage-ring, booster, synchrotron, injection

1

D. Einfeld
CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain

ALBA is a 3rd generation Synchrotron Light Source build in Barcelona, Spain. It is a 3 GeV Light Source with a circumference of roughly 270 m, an emittance of 4.4 nmrad and a design current of 400 mA. The storage ring has 24 straight sections from which 19 can be used for the installation of insertion devices, the rest will be used for injection, RF-cavities and diagnostic. The storage ring has been optimized for a high photon flux density for the users. The 3 GeV booster synchrotron with an emittance smaller the 10 nmrad is installed in the same tunnel. The pre injector is a 100 MeV Linac. The project started officially in 2004. The linac is operating since 2008, the booster since 2010 and the first commissioning phase for the storage ring will be finished in June 2011. This presentation gives an overview of the ALBA project with the emphasis on the results of the commissioning of the three accelerators Linac, booster synchrotron and storage ring.

Slides MOXAA01 [8.891 MB]

MOXBA01

J-PARC Beam Commissioning Progress

beam-losses, injection, extraction, vacuum

6

H. Hotchi
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

The J-PARC is a multi-purpose proton accelerator facility amiming at MW-class output beam power, consisting of a 400 MeV H⁻ linac, a 3-GeV RCS, a 50-GeV MR (Main Ring) and three experimental facilities, the MLF (materials and life science experimental facility), the HD (hadron experimental hall) and the NU (neutrino beam line). The J-PARC beam commissioning started in November 2006 from the linac to the downstream facilities. The current output beam power from the RCS to the MLF users is 210 kW, and the MR delivers 145 kW beam to the NU by fast extraction and a few kW beam to the HD by slow extraction. In this talk, we present a current status of the J-PARC beam commissioning, in which a recent progress in the course of the RCS beam power ramp-up scenario will be described in more detail. This talk will focus on the issues (including beam dynamics), challenges, solutions, and lessons learned during the commissioning and user operation of J-PARC and future plans.

Slides MOXBA01 [2.615 MB]

MOYBA01

Present Status of the ILC Project and Developments

cavity, linear-collider, collider, electron

16

M.C. Ross
Fermilab, Batavia, USA
N.J. Walker
DESY, Hamburg, Germany
A. Yamamoto
KEK, Ibaraki, Japan

Funding: FNAL is operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
The Technical Design of the ILC Project will be finished in late 2012. The Technical Design Report will include a description of the updated design, with a cost estimate and a project plan, and the results of R & D done in support of the ILC. Results from directed ILC R & D are used to reduce the cost and risk associated with the ILC design. We present a summary of key challenges and show how the global R & D effort has addressed them. The most important activity has been in pursuit of very high gradient superconducting RF linac technology. There has been excellent progress toward the goal of practical industrial production of niobium sheet-metal cavities with gradient performance in excess of 35 MV/m. In addition, three purpose-built beam test facilities have been constructed and used to study and demonstrate high current linac performance, electron-cloud beam dynamics and precision beam control. The report also includes a summary of component design studies and conventional facilities cost optimization design studies.

Slides MOYBA01 [9.755 MB]

MOOCA02

Two Beam Test Stand Experiments in the CTF3 Facility

accelerating-gradient, acceleration, diagnostics, ion

29

W. Farabolini, F. Peauger
CEA/DSM/IRFU, France
J. Barranco, S. Bettoni, B. Constance, R. Corsini, M. Csatari, S. Döbert, A. Dubrovskiy, C. Heßler, T. Persson, G. Riddone, P.K. Skowroński, F. Tecker
CERN, Geneva, Switzerland
D. Gudkov, A. Solodko
JINR, Dubna, Moscow Region, Russia
M. Jacewicz, T. Muranaka, A. Palaia, R.J.M.Y. Ruber, V.G. Ziemann
Uppsala University, Uppsala, Sweden

The CLEX building in the CTF3 facility is the place where essential experiments are performed to validate the Two-Beam Acceleration scheme upon which the CLIC project relies. The Drive Beam enters the CLEX after being recombined in the Delay loop and the Combiner Ring in intense beam trains of 24 A – 150 MeV lasting 140 ns and bunched at 12 GHz, although other beam parameters are also accessible. This beam is then decelerated in dedicated structures installed in the Test Beam Line (TBL) and in the Two-Beam Test Stand (TBTS) aimed at delivering bursts of 12 GHz RF power. In the TBTS this power is used to generate a high accelerating gradient of 100 MV/m in specially designed accelerating structures. To assess the performances of these structures a probe beam is used, produced by a small Linac. We reported here the various experiences conducted in the TBTS making use of the versatility the probe beam and of dedicated diagnostics.

Slides MOOCA02 [3.003 MB]

MOODA02

S1-Global Module Tests at STF/KEK

cavity, cryomodule, SRF, feedback

38

D. Kostin, K. Jensch, L. Lilje, A. Matheisen, W.-D. Möller, P. Schilling, M. Schmökel, N.J. Walker, H. Weise
DESY, Hamburg, Germany
C. Adolphsen, C.D. Nantista
SLAC, Menlo Park, California, USA
M. Akemoto, S. Fukuda, K. Hara, H. Hayano, N. Higashi, E. Kako, H. Katagiri, Y. Kojima, Y. Kondo, T. Matsumoto, H. Matsushita, S. Michizono, T. Miura, H. Nakai, H. Nakajima, K. Nakanishi, S. Noguchi, N. Ohuchi, T. Saeki, M. Satoh, T. Shidara, T. Shishido, T. Takenaka, A. Terashima, N. Toge, K. Tsuchiya, K. Watanabe, S. Yamaguchi, A. Yamamoto, Y. Yamamoto, K. Yokoya
KEK, Ibaraki, Japan
T.T. Arkan, S. Barbanotti, M.A. Battistoni, H. Carter, M.S. Champion, A. Hocker, R.D. Kephart, J.S. Kerby, D.V. Mitchell, T.J. Peterson, Y.M. Pischalnikov, M.C. Ross, W. Schappert, B.E. Smith
Fermilab, Batavia, USA
A. Bosotti, C. Pagani, R. Paparella, P. Pierini
INFN/LASA, Segrate (MI), Italy

S1-Global collaborative effort of INFN, DESY, FNAL, SLAC and KEK, recently successfully finished at KEK as a part of ILC GDE, is an important milestone for the ILC. International collaboration of three regions, Asia, North America and Europe, proved to be efficient on the construction and cold tests of the accelerating module consisting of 8 SRF cavities; 2 from FNAL, 2 from DESY and 4 from KEK. Three different cavity tuning systems were tested together with two types of high power couplers. The module was cooled down three times which enabled extensive high power tests with cavities, performance limits investigation, Lorentz force detuning tests, simultaneous multiple cavities operation and other activities such as an operation test of distributed RF scheme with low level RF feedback. The results of this S1-Global module test are presented and discussed.

Slides MOODA02 [2.982 MB]

MOODA03

First Characterization of a Fully Superconducting RF Photoinjector Cavity

cavity, cathode, laser, solenoid

41

A. Neumann, W. Anders, R. Barday, A. Jankowiak, T. Kamps, J. Knobloch, O. Kugeler, A.N. Matveenko, T. Quast, J. Rudolph, S.G. Schubert, J. Völker
HZB, Berlin, Germany
P. Kneisel
JLAB, Newport News, Virginia, USA
R. Nietubyc
The Andrzej Soltan Institute for Nuclear Studies, Centre Swierk, Swierk/Otwock, Poland
J.K. Sekutowicz
DESY, Hamburg, Germany
J. Smedley
BNL, Upton, Long Island, New York, USA
V. Volkov
BINP SB RAS, Novosibirsk, Russia
G. Weinberg
FHI, Berlin, Germany
I. Will
MBI, Berlin, Germany

As a first step towards a high brightness, high average current electron source for the BERLinPro ERL a fully superconducting photo-injector was developed by HZB in collaboration with JLab, DESY and the A. Soltan Institute. This cavity-injector ensemble is made up of a 1.6-cell superconducting cavity with a superconducting lead cathode deposited on the half-cell backwall. A superconducting solenoid is used for emittance compensation. This system, including a diagnostics beamline, has been installed in the HoBiCaT facility to serve as a testbed for beam dynamics studies and to test the combination SRF cavity and superconducting solenoid. This paper summarizes the characterization of the cavity in this configuration including Q measurements, dark current tests and field-stability analyses.

Slides MOODA03 [10.343 MB]

MOOCB01

Study on the Realignment Plan for J-PARC Linac after the Tohoku Earthquake in Japan

DTL, alignment, simulation, quadrupole

44

M. Ikegami
KEK, Ibaraki, Japan
T. Morishita
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

A 9.0-magnitude earthquake struck eastern Japan on March 11, 2011, and it gave rise to damages to the buildings of the J-PARC facilities. In particular, the earthquake caused a deformation of the J-PARC linac tunnel resulting an alignment error of several tens of millimeters in both horizontal and vertical directions. It also caused a change in the relative position between the linac and other facilities of J-PARC complex. To restore the beam operation, we should establish a reasonable realignment plan for J-PARC linac taking various constraints into account and possibly tolerating some residual misalignment. In this paper, we show a study on the realignment plan for J-PARC linac including evaluation of the effect of residual misalignment with particle simulations.

Slides MOOCB01 [2.659 MB]

MOOCB03

A Novel Method for Quasi-non-interceptive Beam Profile Measurement in a Linac

coupling, diagnostics, emittance, beam-transport

50

A.V. Aleksandrov
ORNL, Oak Ridge, Tennessee, USA

Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.
Beam profile diagnostics is an important tool for understanding beam dynamics in accelerators. Non-interceptive diagnostics have many great advantages but often are difficult in implementation. We suggest a method of measuring beam profiles that is not truly non-interceptive, because beam has to be intercepted at some point, preferably in the beginning of the linac. But significant difference from a conventional interceptive measurement is that beam is not intercepted at any of the points of measurement along the linac. One important application is measuring beam profiles within cryostats of a super-conducting linac. The equipment required for implementing this diagnostic is simple: a set of slits in the beginning of the accelerator, and a Beam Position Monitor (BPM) in the point of measurement. Beam profiles can be measured simultaneously at every BPM along the linac. In this paper we will discuss details of the method, its limitations, and effect of non-linearity, coupling and space charge. Results of a demonstration experiment at SNS will be presented and discussed.

Slides MOOCB03 [3.365 MB]

MOODB01

Dynamics of the IFMIF Very High-intensity Beam

rfq, emittance, space-charge, cryomodule

53

P.A.P. Nghiem, R.D. Duperrier, A. Mosnier, D. Uriot
CEA/DSM/IRFU, France
N. Chauvin, O. Delferrière, W. Simeoni
CEA/IRFU, Gif-sur-Yvette, France
M. Comunian
INFN/LNL, Legnaro (PD), Italy
C. Oliver
CIEMAT, Madrid, Spain

For the purpose of material studies for future nuclear fusion reactors, the IFMIF deuteron beams present a simultaneous combination of unprecedentedly high intensity (2x125 mA CW), power (2x5 MW) and space charge. Special considerations and new concepts have been developed in order to overcome these challenges. The global strategy for beam dynamics design in the 40 MeV IFMIF accelerators is presented, stressing on the control of micro-losses, and the possibility of on-line fine tuning. The obtained results are then analysed in terms of beam halo and emittance growth.

Slides MOODB01 [3.807 MB]

MOODB02

RF Modeling Plans for the European Spallation Source

cavity, HOM, electron, beam-losses

56

S. Molloy, M. Lindroos, S. Peggs
ESS, Lund, Sweden
R. Ainsworth
Royal Holloway, University of London, Surrey, United Kingdom
R.J.M.Y. Ruber
Uppsala University, Uppsala, Sweden

The European Spallation Source (ESS) will be the world's most powerful next generation neutron source. The ESS linac is designed to accelerate highly charged bunches of protons to a final energy of 2.5 GeV, with a design beam power of 5 MW, for collision with a target used to produce the high neutron flux. In order to achieve this several stages of RF acceleration are required, each using a different technology. The high beam current and power require a high degree of control of the accelerating RF, and the specification that no more than 1 W/m of losses will be experienced means that the excitation and decay of the HOMs must be very well understood. Experience at other high power machines also implies that an understanding of the generation and subsequent trajectories of any field-emitted electrons should be understood. Thermal detuning of the HOM couplers due to multipacting is a serious concern here. This paper will outline the RF modeling plans - including the construction of mathematical models, simulations of HOMs, and multipacting - during the current Accelerator Design Update phase, and will discuss several of the more important issues for ESS.

Slides MOODB02 [48.641 MB]

MOPC001

Linac Waveguide Upgrade at the Australian Synchrotron Light Source

klystron, booster, controls, synchrotron

62

R.T. Dowd, G. LeBlanc, K. Zingre
ASCo, Clayton, Victoria, Australia

The Australian Synchrotron Light Source (ASLS) uses a 100 MeV linac as the start of the acceleration chain for the injector. The two main accelerating structures of linac are normally fed by independent pulsed klystrons. A recent upgrade to the waveguide system has allowed for a single klystron to power both accelerating structures. While this operation mode delivers a reduced total beam energy, the operation of only a single klystron results in less wear and enhanced robustness against klystron breakdown. Commissioning results of single klystron operation of the linac are shown and future benefits are detailed.

MOPC002

Flow Induced Vibrations of the CLIC X-band Accelerating Structures

quadrupole, alignment, synchrotron, resonance

65

T.K. Charles, K. Ryan
Monash University, Melbourne, Australia
M.J. Boland
ASCo, Clayton, Victoria, Australia
G. Riddone
CERN, Geneva, Switzerland
A. Samoshkin
JINR, Dubna, Moscow Region, Russia

Turbulent cooling water in the Compact Linear Collider (CLIC) accelerating structures will inevitably induce some vibrations. The maximum acceptable amplitude of vibrations is small, as vibrations in the accelerating structure could lead to beam jitter and alignment difficulties. A Finite Element Analysis model is needed to identify the conditions under which turbulent instabilities and significant vibrations are induced. Due to the orders of magnitude difference between the fluid motion and the structure's motion, small vibrations of the structure will not contribute to the turbulence of the cooling fluid. Therefore the resonant conditions of the cooling channels presented in this paper, directly identify the natural frequencies of the accelerating structures to be avoided under normal operating conditions. In this paper a 2D model of the cooling channel is presented finding spots of turbulence being formed from a shear layer instability. This effect is observed through direct visualisation and wavelet analysis.

MOPC009

Design of a Pi/2 Mode S-Band Low Energy TW Electron Linear Accelerator

electron, coupling, acceleration, simulation

80

H. Shaker
IPM, Tehran, Iran
F. Ghasemi
sbu, Tehran, Iran
H. Shaker
CERN, Geneva, Switzerland

This design is related to a Pi/2 mode S-Band low energy TW electron linear accelerator which is in the construction stage. This project is supported by the school of particles and accelerators, institute for research in fundamental sciences (IPM), Tehran, Iran. This design consists of a buncher and an accelerating structure that are joined and two couplers for the input/output feedings. At each design stage, different methods (analytical or numerical) are used to confirm the results and also to have a better understanding.

MOPC010

Phase-Modulation SLED Operation Mode at Elettra

cavity, LLRF, klystron, target

83

C. Serpico, P. Delgiusto, A. Fabris, F. Gelmetti, M.M. Milloch, A. Salom, D. Wang
ELETTRA, Basovizza, Italy

FERMI@Elettra is the soft X-ray, fourth generation light source facility at the Elettra Laboratory in Trieste, Italy. It is based on a seeded FEL, driven by a normal conducting linac that is presently expected to operate at 1.5 GeV. The last seven backward traveling wave structures have been equipped with a SLED system. Due to breakdown problems inside the sections, that was the result of high peak fields generated during conventional SLED operation, the sections experienced difficulties in reaching the desired gradients. To lower the peak field and make the compressed pulse “flatter”, phase-modulation of the SLED drive power will be implemented. A description of the phase modulation of the drive power and the results achieved will be reported in the following paper.

MOPC015

S-band Vacuum Isolator and Circulator for Injector System of SPring-8 Linac

vacuum, cavity, insertion, injection

95

T. Taniuchi, H. Hanaki, S. Suzuki
JASRI/SPring-8, Hyogo-ken, Japan
A. Miura, K. Shinohara, S. Tsuruoka
Nihon Koshuha Co. Ltd, Yokohama, Japan

A pressurized sulfur hexafluoride (SF6) waveguide system at an injector section of SPring-8 linac, will be replaced with a vacuum waveguide system in order to renew aged equipments and improve a phase stability. For this renewal, RF isolator and a circulator operated in vacuum, are newly developed. High power RF test for these components were performed and a good result for RF and vacuum characteristics were obtained.

MOPC017

Thermal Analyses of an RF Input Coupler for the IFMIF/EVEDA RFQ Linac

rfq, cavity, coupling, beam-transport

101

S. Maebara
JAEA, Ibaraki-ken, Japan

In the design of prototype RFQ linac for the IFMIF/EVEDA Project, a coupled cavity type of RFQ, which has a longitudinal length of 9.78m, was proposed to accelerate deuteron beam up to 5MeV. The operation frequency of 175MHz was selected to accelerate a large current of 125mA in CW mode. The driving RF power of 1.28 MW by 8 RF input couplers has to be injected to the RFQ cavity. As the RF input coupler design, RF losses including a loop antenna and an RF vacuum window, based on a 6 1/8 inch co-axial waveguide were calculated. In this conference, these results and thermal analysis results in CW operation mode will be presented in details.

MOPC020

Development of an S-band Multi-cell Accelerating Cavity for RF Gun and Booster Linac

gun, cavity, booster, electron

110

T. Aoki, K. Sakaue, M. Washio
RISE, Tokyo, Japan
A. Deshpande
SAMEER, Mumbai, India
M.K. Fukuda, N.K. Kudo, T. Takatomi, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan

Funding: Work supported by JST Quantum Beam Program
We have been developing a photocathode rf gun. The rf gun with multi cell can produce a high energy electron beam, so it may be used for numerous applications such as medicine and industry. At Laser Undulator Compact X-ray source (LUCX), we have developed a compact X-ray source based on inverse Compton scattering. Using a multi cell rf gun will make possible for the X-ray source to use for such applications. S-band 3.5 cell rf electron gun which is 20 cm long can produce more than 10 MeV electron beam. According to the simulation, it is said that the emittance of 3.5 cell rf gun is as low as that of 1.6 cell rf gun. The electromagnetic design has been performed with the code SuperFish, and the particle tracing by Parmela. The new rf gun is already installed and produced a high quality electron beam with energy of more than 10 MeV. As a consequence of the substantial efforts of developing rf cavity, we decide to make a compact RF accelerating structure with more cell for achieving a smaller system. The measurement results of using the 3.5 cell rf gun, the design of 12 cell booster cavity, and current status of 12 cell cavity manufacturing will be presented at the conference.

MOPC030

The C-band Traveling-wave Accelerating Structure for Compact XFEL at SINAP*

vacuum, controls, impedance, status

133

W. Fang, Q. Gu, Z.T. Zhao
SINAP, Shanghai, People's Republic of China
D.C. Tong
TUB, Beijing, People's Republic of China

The R&D of C-band accelerating structure has been launched two years ago at Shanghai Institute of Applied Physics, it will be used for the future compact hard X-ray FEL. The 1st C-band traveling-wave accelerating structure is ready for the high power test now. This structure is the preliminary model for the research of the technology of microwave test and tuning, arts and crafts and high power test. This paper presents the process of fabrication, cold test and tuning results.

MOPC032

Improvement of the RF System for the PEFP 100 MeV Proton Linac*

LLRF, controls, proton, EPICS

139

K.T. Seol, Y.-S. Cho, H.S. Kim, H.-J. Kwon, Y.-G. Song
KAERI, Daejon, Republic of Korea

Funding: This work is supported by the Ministry of Education, Science and Technology of the Korean Government.
The 100 MeV proton linear accelerator of the Proton Engineering Frontier Project (PEFP) has been developed and will be installed in Gyeong-ju site. The 20 MeV accelerator operated in Korea Atomic Energy Research Institute (KAERI) site will be also moved and reinstalled. The LLRF control systems for the 20 MeV accelerator were improved and have been operated within the stability of ±1% in RF amplitude and ±1 degree in RF phase. 7 sets of the extra LLRF control system will be installed with a RF reference system for the 100 MeV accelerator. Waveguide layout was also improved to install HPRF systems for the 100 MeV accelerator. Some of the HPRF components including klystrons, circulators, and RF windows are under purchase. The waveguide sections penetrating into the tunnel, which are fixed in a concrete floor with the bending structure for radiation shielding, were fabricated into a piece of waveguide to prevent the moisture and any foreign debris inside the concrete block. The details of the RF system improvement are presented.

MOPC035

Design and Machine Features of 2.2-m C-band Accelerating Structure

cavity, accelerating-gradient, vacuum, electron

148

C.H. Yi, M.-H. Cho, S.H. Kim, H. Lee
POSTECH, Pohang, Kyungbuk, Republic of Korea
W. Namkung
PAL, Pohang, Kyungbuk, Republic of Korea

Funding: This work is partly supported by the MEST, Korea and POSTECH BK21 Program. And this work was supported by the Korea Student Aid Foundation (KOSAF) grant funded by the Korea government.
A compact linac system is designed using a longer accelerating column in a C-band linac. It reduces the total number of RF units for the given linac beam energy and results in the cost-effective use of RF powers. For the 10 GeV PAL-XFEL project, a C-band accelerating column of 2.2-m long is investigated, which is 22% longer than 1.8-m for the SACLA at SPring-8. The detailed RF and thermal characteristics are presented by an analytic model.

MOPC042

RF and Accelerating Structure of 12 MeV UPC Race-track Microtron

vacuum, coupling, microtron, controls

169

Yu.A. Kubyshin, X. Gonzalez Arriola
UPC, Barcelona, Spain
D. Carrillo, L. García-Tabarés, F. Toral
CIEMAT, Madrid, Spain
S.J. Mathot
CERN, Geneva, Switzerland
G. Montoro
EPSC, Castelldefels, Spain
V.I. Shvedunov
MSU, Moscow, Russia

We describe the design and technical characteristics of a C-band SW accelerating structure of a 12 MeV race-track microtron, which is under construction at the Technical University of Catalonia, and its RF system with a 5712 MHz magnetron as a source. Results of cold tests of the accelerating structure, before and after the brazing, and of high-power tests of the RF system at a special stand are reported. The main features of the magnetron frequency stabilization subsystem are also outlined.

MOPC043

Electromagnetic Simulations of the Input Power Couplers for the ESS-Bilbao RFQ

rfq, vacuum, cavity, radio-frequency

172

O. Gonzalez, I. Bustinduy, N. Garmendia, J.L. Munoz, A. Velez
ESS Bilbao, Bilbao, Spain
F.J. Bermejo
Bilbao, Faculty of Science and Technology, Bilbao, Spain
V. Etxebarria, J. Portilla
University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain

An input power system is currently being designed at ESS-Bilbao in order to inject the RF power provided by a klystron into the RFQ as part of the linac. In this work, some input power couplers based on a coaxial topology are carefully studied from an electromagnetic point of view. As we will show, the electrical properties of the ceramic window used to ensure the vacuum of the RFQ crucially deteriorates the matching of the devices. To overcome this drawback, a full-wave electromagnetic simulator is used to optimize the coupler dimensions in order to minimize both the return and insertion losses.

MOPC047

RF Design of the Re-buncher Cavities for the LIPAC Deuteron Accelerator

cavity, impedance, vacuum, beam-transport

184

A. Lara, I. Podadera, F. Toral
CIEMAT, Madrid, Spain

Funding: Work partially supported by Spanish Ministry of Science and Innovation under project ENE2009-11230.
Re-buncher cavities are an essential component of LIPAC (Linear IFMIF Prototype Accelerator), presently being built at Rokkasho (Japan). The deuteron beam exiting from the RFQ (Radio Frequency Quadrupole) structure has to be properly adapted to the superconducting RF (SRF) linac. Re-bunchers are placed in the Medium Energy Beam Transport (MEBT) line and their objective is to longitudinally focus the deuteron beam. IFMIF re-bunchers must provide a 350 kV E0LT at 175 MHz continuous wave (CW). The available length for the re-buncher is limited by the general layout of the MEBT. The high power dissipation derived from the high effective voltage and the short available length is an important design challenge. Four different normal conducting cavity designs were investigated: the pillbox type, double gap coaxial resonators, and multi-gap quarter wave and H resonators. The performance of these cavities was studied with the numerical codes HFSS and ANSYS. The fundamental frequency and field pattern of each re-buncher was investigated in HFSS. This work presents the results of such analyses.

MOPC053

Mechanical Design and Fabrication Studies for SPL Superconducting RF Cavities

cavity, niobium, SRF, proton

199

S. Atieh, G. Arnau-Izquierdo, I. Aviles Santillana, O. Capatina, T. Renaglia, T. Tardy, N. Valverde Alonso, W. Weingarten
CERN, Geneva, Switzerland

CERN’s R&D programme on the Superconducting Proton Linac’s (SPL) superconducting radio frequency (SRF) elliptical cavities made from niobium sheets explores new mechanical design and consequently new fabrication methods, where several opportunities for improved optimization were identified. A stainless steel helium vessel is under design rather than a titanium helium vessel using an integrated brazed transition between Nb and the SS helium vessel. Different design and fabrication aspects were proposed and the results are discussed hereafter.

MOPC055

High Power Test of the First PIMS Cavity for Linac4

cavity, pick-up, vacuum, klystron

205

F. Gerigk, J.-M. Giguet, P. Ugena Tirado, R. Wegner
CERN, Geneva, Switzerland

The PI-Mode Structure (PIMS) accelerates the Linac4 beam from 100 to 160 MeV. Twelve 7-cell cavities will be installed in the linac, with a gradient of ~4 MV/m and operating at a frequency of 352.2 MHz. A full-power prototype has been constructed at CERN in 2010 and was high- power tested in autumn 2010. Peak power tests at the Linac4 duty cycle and high-average power tests at increased duty cycles were completed successful, so that this prototype will be the first of the 12 cavities to be installed in Linac4. This paper reports on the high-power tests and the conditioning experience.

MOPC056

The Linac4 Power Coupler

cavity, coupling, vacuum, simulation

208

F. Gerigk, J.-M. Giguet, E. Montesinos, B. Riffaud, P. Ugena Tirado, R. Wegner
CERN, Geneva, Switzerland

Linac4 employs 3 types of accelerating structures after the RFQ: a Drift Tube Linac (DTL), a Cell-Coupled DTL (CCDTL), and a Pi-Mode Structure (PIMS) to accelerate the beam to 160 MeV. The structures are designed for a peak power of 1 MW per coupler, which consists of two parts: a ceramic window, which separates the cavity vacuum from the air in the wave-guides, and a so-called "coupling T", which couples the RF power through an iris to the cavity. In the frame of the Linac4 R&D both devices have been significantly improved with respect to their commonly used design. On the coupler side, the wave-guide short circuit with its matched length has been replaced by a fixed length λ/4 short circuit. The RF matching is done by a simple piston tuner, which allows a quick matching to different cavity quality factors. In the window part, which usually consists of a ceramic disc and 2 pieces of wave-guides with matching elements, the wave-guide sections could be completely suppressed, so that the window became very compact, lightweight, and much simpler to manufacture. In this paper we present electromagnetic simulations, and tests on first prototypes, which were constructed at CERN.

MOPC059

The Plane Wave Transformer Linac Development at NSRRC

simulation, impedance, cavity, electron

217

A. Sadeghipanah, J.-Y. Hwang, W.K. Lau
NSRRC, Hsinchu, Taiwan
T.H. Chang
NTHU, Hsinchu, Taiwan

A Plane-Wave-Transformer (PWT), standing wave linac operating at S-band frequency (2.9979 GHz) is being developed at NSRRC. This structure offers the advantages of high efficiency, compactness, fabrication simplicity and cost. The PWT prototype at NSRRC consists of three cells with two half-cells at the ends, separated by a set of four flat disks suspended and cooled by four water tubes inside a large cylindrical tank. To fully understand its physical properties, numerical modeling of the PWT prototype has been carried out by using the 2-D code SUPERFISH and 3-D code MAFIA. In this paper, we describe the principle properties of this structure, the electric parameters obtained from numerical simulations, and heat dissipation calculation. The mechanical design for prototype linac is also reported.

MOPC060

Bunching-frequency Multiplication for a THz Pulse-train Photoinjector

electron, bunching, laser, acceleration

220

Y.-C. Huang, F.H. Chao, C.H. Chen, K.Y. Huang
NTHU, Hsinchu, Taiwan

Funding: This work is supported by National Science Council under Contract NSC 99-2112-M-007 -013 -MY3.
A THz-pulse-train photoinjector* employs a THz-pulse-train laser as its driver laser to generate a beam with a bunching frequency in the THz range. However a laser frequency is on the order of a few hundred THz. It is not possible to generate a beam from the pulse-train photoinjector with a bunching frequency exceeding the laser’s carrier frequency. In view of the strong demand for a compact x-ray free-electron laser (FEL), it is highly desirable to multiply the bunching frequency of the beam from a pulse-train injector to the x-ray frequencies. We propose to chirp the energy of the THz electron pulse train in an accelerator and compress the whole beam in a magnet to increase the electron bunching frequency. Our study shows a compression ratio or a bunching-frequency multiplication factor of a few tens is achievable from a properly designed magnetic chicane compressor. The bunching factor, however, is unfortunately degraded due to the energy chirp, emittance growth, and wake-field generation. In the conference, we will show that a bunching factor of a few ppm in the bunch-frequency multiplied beam is sufficient to build up the FEL power from a 10-time length reduced undulator.
* Y. C. Huang, “Laser-beat-wave bunched beam for compact superradiance sources,” International Journal of Modern Physics B, Vol. 21 Issue 3/4, p277-286 (2007).

MOPC068

LANSCE RF System Improvements for Current and Future Programs*

klystron, cavity, neutron, proton

238

D. Rees, J.L. Erickson, R.W. Garnett, J.T.M. Lyles, L. Rybarcyk
LANL, Los Alamos, New Mexico, USA

The Los Alamos Neutron Science Center (LANSCE) is in the midst of an upgrade of the RF systems. This project will return LANSCE to its historical operating capability and sustain facility operations into the next decade. The LANSCE accelerator provides pulsed protons and spallation neutrons for defense and civilian applications. This project involves replacing all the existing 201 MHz RF stations and 805 MHz klystrons. LANSCE is also currently in the conceptual design phase of a program called the Material Test Station (MTS) to establish a 1 MW target station to irradiate fast reactor fuels and materials. A pre conceptual design is also in progress to extend the capabilities of MTS to a 2 MW target that will enable the first in a new generation of scientific facilities for the materials community. The emphasis of this new facility is "Matter-Radiation Interactions in Extremes" (MaRIE) which will be used to discover and design the advanced materials needed to meet 21st century national security and energy security challenges. The design and test results of the new RF systems will be presented as well as the RF system changes required to support the new missions.

MOPC072

Design of an RF Feed System for Standing-wave Accelerator Structures

cavity, coupling, wakefield, damping

244

J. Neilson, V.A. Dolgashev, S.G. Tantawi
SLAC, Menlo Park, California, USA

Travelling wave (TW) accelerator structures are known to suffer from several deficiencies. A breakdown in one of the cells propagates towards the source. This results in damage to upstream cells in addition to the cell where the breakdown was initiated. The deficiencies of TW accelerator structures can be overcome by using standing wave (SW) cells that are fed in parallel. An RF breakdown is contained to the cell where it originates. This eliminates upstream cell damage and the resulting changes in phase shift between cells. In addition the feed structure can provide a high conductance port for vacuum pumping. We have completed the design of a parallel fed SW structure with a directional coupler for each cell and serpentine waveguide connection between couplers. This design approach improves isolation between the cells resulting in the maximum increase in the operational robustness of the accelerator structure. The design uses four feed arms spaced uniformly around the cell circumference to suppress dipole modes and improve damping of low order wakefields. Construction of a test structure in now underway and is scheduled for testing in October of this year.

MOPC079

Status of the Low Beta 0.07 Cryomodules for SPIRAL2

cavity, cryomodule, LLRF, vacuum

256

P. Bosland, P. Carbonnier, F. Eozénou, P. Galdemard, O. Piquet
CEA/DSM/IRFU, France
M. Anfreville, C. Madec, L. Maurice
CEA/IRFU, Gif-sur-Yvette, France
P.-E. Bernaudin, R. Ferdinand
GANIL, Caen, France
Y. Gomez-Martinez
LPSC, Grenoble Cedex, France
A. Pérolat
CEA, Gif-sur-Yvette, France

The status of the low beta cryomodules for SPIRAL2, supplied by the Irfu institute of CEA Saclay, is reported in this paper. We summarise in three parts the RF tests performed on the cavities in vertical cryostat, the RF power tests of the qualifying cryomodule performed in 2010 and the RF power tests performed in 2011 on the first cryomodule of the series

MOPC080

First Considerations Concerning an Optimized Cavity Design for the Main Linac of BERLinPro

cavity, HOM, coupling, impedance

259

B. Riemann, T. Weis
DELTA, Dortmund, Germany
W. Anders, J. Knobloch, A. Neumann
HZB, Berlin, Germany
H.-W. Glock, C. Potratz, U. van Rienen
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
F. Marhauser
JLAB, Newport News, Virginia, USA

Funding: work supported by BMBF under contracts 05K10PEA and 05K10HRC
The Berlin Energy Recovery Linac Project (BERLinPro) is designed to develop and demonstrate CW linac technology and expertise required to drive next-generation Energy Recovery Linacs. Strongly HOM-damped multicell 1.3 GHz cavities are required for the main linac. The optimization of the cavities presented here is primarily based on the CEBAF 1.5 GHz 5-cell high-current cavity design, including HOM waveguide couplers. The cavity was scaled to 1.3 GHz and extended to 7 cells. Modifications to the end group design have also been studied. An effort was also made to reduce the ratio Epk/Eacc while still permitting HOMs to propagate.

MOPC082

Status of the 325 MHz SC CH-Cavity at IAP Frankfurt

cavity, simulation, status, electron

265

M. Busch, F.D. Dziuba, H. Podlech, U. Ratzinger
IAP, Frankfurt am Main, Germany
M. Amberg, K. Aulenbacher
HIM, Mainz, Germany
W.A. Barth, S. Mickat
GSI, Darmstadt, Germany

Funding: BMBF contract no. 06FY161I
At the Institute for Applied Physics (IAP), University of Frankfurt, a s.c. 325 MHz CH-Cavity is under development for future beam tests at GSI UNILAC, Darmstadt. The cavity with 7 accelerating cells has a geometrical beta of 0.15 corresponding to 11.4 AMeV. The design gradient is 5 MV/m. The geometry of this resonator was optimized with respect to a compact design, low peak fields, surface processing, power coupling and tuning. Furthermore a new tuning system based on bellow tuners inside the resonator will control the frequency during operation. After rf tests in Frankfurt the cavity will be tested with a 10 mA, 11.4 AMeV beam delivered by the GSI UNILAC. In this paper rf simulations, multipacting analysis as well as thermal calculations will be presented.

MOPC083

Structural Mechanics of Superconducting CH Cavities

cavity, simulation, controls, resonance

268

M. Amberg, K. Aulenbacher
HIM, Mainz, Germany
W.A. Barth, S. Mickat
GSI, Darmstadt, Germany
M. Busch, F.D. Dziuba, H. Podlech, U. Ratzinger
IAP, Frankfurt am Main, Germany

The superconducting CH-structure (Crossbar-H-mode) is a multi-cell drift tube cavity for the low and medium energy range operated in the H21-mode, which has been developed at the Institute for Applied Physics (IAP) of Frankfurt University. With respect to different high power applications two types of superconducting CH-structures (f = 325 MHz, β = 0.16, seven cells and f = 217 MHz, β = 0.059, 15 cells) are presently under construction and accordingly under development. The structural mechanical simulation is a very important aspect of the cavity design. Furthermore, several simulations with ANSYS Workbench have been performed to predict the deformation of the cavity walls due to the cavity cool-down, pressure effects and mechanical vibrations. To readjust the fast frequency changes in consequence of the cavity shape deformation, a new concept for the dynamic frequency tuning has been investigated, including a novel type of bellow-tuner.

MOPC084

The Superconducting cw LINAC Demonstrator for GSI

cavity, solenoid, ion, acceleration

271

F.D. Dziuba, M. Busch, H. Podlech, U. Ratzinger
IAP, Frankfurt am Main, Germany
M. Amberg, K. Aulenbacher
HIM, Mainz, Germany
W.A. Barth, S. Mickat
GSI, Darmstadt, Germany

Funding: BMBF Contr. No. 06FY9089I, Helmholtz Institut Mainz
At GSI a new, superconducting (sc) continuous wave (cw) LINAC is under design in cooperation with the Institute for Applied Physics (IAP) of Frankfurt University and the Helmholtz Institut Mainz (HIM). This proposed LINAC is highly requested by a broad community of future users to fulfill the requirements of nuclear chemistry, nuclear physics, and especially in the research field of Super Heavy Elements (SHE). In this context the preliminary layout of the LINAC has been carried out by IAP. The main acceleration of up to 7.3 AMeV will be provided by nine sc Crossbar-H-mode (CH) cavities operated at 217 MHz. Currently, a prototype of the cw LINAC as a demonstrator is under development. The demonstrator comprises a sc CH-cavity embedded between two sc solenoids mounted in a horizontal cryomodule. A full performance test of the demonstrator in 2013/14 by injecting and accelerating a beam from the GSI High Charge Injector (HLI) is one important milestone of the project. The status of the demonstrator is presented.

MOPC085

Quality Assessment for Industrially Produced High-Gradient Superconducting Cavities

cavity, niobium, superconducting-cavity, SRF

274

F. Schlander, S. Aderhold, E. Elsen, D. Reschke, M. Wenskat
DESY, Hamburg, Germany

Funding: This work is supported by the Commission of the European Communities under the 7th Framework Programme “Construction of New Infrastructures – Preparatory Phase”, contract number 206711.
A series of some 600 superconducting 1.3 GHz cavities will start being delivered to DESY by industry in early 2012. Although a considerably smaller gradient satisfies the needs for the European XFEL the electro-polished cavities (50% of the delivery) are deemed to be suitable for gradients in excess of 35 MV/m, the performance goal of the International Linear Collider (ILC). Specifically 24 cavities will be supplied without helium tank to enable further investigations. The results may serve to improve overall performance; limitations such as field emission and thermal breakdown of superconductivity ("quench") are still under investigation. For this matter the DESY ILC group has developed tools to monitor aspects of the cavity fabrication. An automated optical mapping system (OBACHT) is being commissioned and will be complemented by software for automated cavity surface feature recognition. For cold RF tests a Second Sound setup for locating the positions of the thermal breakdown is routinely used. These diagnostic tools will give guidance on post-processing cavities for best performance. The current status of these projects will be described.

MOPC088

Bead-pull Measurement using Phase-Shift Technique in Multi-cell Elliptical Cavity

cavity, vacuum, controls, monitoring

280

S. Ghosh, A. Mandal, S. Seth, S.S. Som
DAE/VECC, Calcutta, India

The project on the development of high-beta multi-cell elliptical shape superconducting rf linac cavity at around 704 MHz has been funded at VECC, Kolkata, India. A full-scale copper prototype cavity has been designed and fabricated. There are 5 distinct modes exist in the cavity and the accelerating mode is pi-mode in which each cell operates at same frequency with phase difference of 180 degrees between two neighboring cells. A fully automated bead-pull measurement setup has been developed for analyzing these modes and field profile distribution at different modes in such type of linac cavity. A special measurement method inside the cavity using phase-shift technique is proposed in this paper, which describes the development of mechanical setup comprising pulleys and stepper motor–gear arrangement, PC-based control system for precise movement of bead using stepper motor, measurement using VNA, development of software for data acquisition & automation and measurement results for the 5-cell copper prototype cavity.

MOPC089

RF Simulations for the QWR Cavities of PIAVE-ALPI

cavity, simulation, ion, beam-losses

283

M. Comunian, F. Grespan, A. Palmieri
INFN/LNL, Legnaro (PD), Italy

The PIAVE-ALPI linac is composed of several families of QWR cavities. In order to have a thorough description of the accelerator in terms of beam dynamics, a detailed field mapping of the accelerating cavities is necessary, including non-linear behavior of the off-axis fields, as well as the steering and dispersion effects due to transverse components. For such a purpose, a set of RF simulation was accomplished, with the codes HFSS and COMSOL. The details about these simulations and the main outcomes and results will be described in this article.

MOPC091

Status of the XFEL 3.9 GHz Injector Section

cavity, cryogenics, cryomodule, status

289

P. Pierini, M. Bonezzi, A. Bosotti, M. Fusetti, P.M. Michelato, L. Monaco, R. Paparella, D. Sertore
INFN/LASA, Segrate (MI), Italy
E. Vogel
DESY, Hamburg, Germany

The European XFEL will use a superconducting third harmonic section to achieve the necessary beam quality for the FEL process. The concept has been successfully proven at the FLASH linac in DESY, with a 4 cavity superconducting module contributed by FNAL. The design of the third harmonic system at the XFEL injector is being finalized and prototypes of the components (cavities and couplers) have been fabricated and are currently in the testing stage. The paper will provide a status of the activities.

MOPC095

Superconducting Cavity R&D for ILC at MHI

cavity, HOM, superconducting-cavity, status

298

H. Hitomi, H. Hara, F. Inoue, K. Kanaoka, K. Sennyu, T. Yanagisawa
MHI, Kobe, Japan

We have developed and manufactured some superconducting RF cavity for STF project in KEK. In recent vertical test in KEK, the MHI-#12 cavity which is one of cavities for STF phase 2 project reached ILC specification(max Eacc was about 40MV/m). So techniques for manufacturing cavity is making steady progress in MHI. To be realized ILC project, we also try to decrease the manufacturing cost by using some new techniques, for example Laser Beam Welding, deep drawing, seamless dumbbell, etc. In this meeting, we will report recent MHI's activities for ILC.

MOPC101

Vertical Test of PEFP Prototype SRF Cavity

cavity, accelerating-gradient, electron, SRF

307

H.S. Kim, Y.-S. Cho, H.-J. Kwon
KAERI, Daejon, Republic of Korea

Funding: This work was supported by Ministry of Education, Science and Technology of the Korean Government.
The PEFP Proton linac is a 100-MeV machine which consists of a proton injector, a 3-MeVRFQ and 100-MeV DTL. For the extension of the machine beyond 100 MeV, SRF technology is under consideration. As a prototyping activity, a superconducting RF cavity with a geometrical beta of 0.42 and a resonant frequency of 700 MHz has been designed, fabricated and tested. The cavity is an elliptical shape with 5 cells stiffened by double-ring structure. A design accelerating gradient is 8.0 MV/m at the operating temperature of 4.2 K and maximum duty factor is 9%. For the vertical test of the cavity, a cryostat with a vacuum jacket and multi-layer insulation was prepared. The RF system for driving the cavity is based on PLL to track the resonant frequency. In case of lack of RF power, a two-way RF power combiner based on splitted coaxial transmission line is considered. The details of the vertical test setup and test results will be presented in this paper.

MOPC109

Suppression of Coupler Kicks in 7-Cell Main Linac Cavities for Cornell's ERL

cavity, emittance, resonance, simulation

331

N.R.A. Valles, M. Liepe, V.D. Shemelin
CLASSE, Ithaca, New York, USA

Funding: Supported by NSF award DMR-0807731
Cornell is developing a 5 GeV Energy Recovery Linac operating at 100 mA with very small emittances (~30 pm at 77 pC bunch charge) in the horizontal and vertical directions. We investigate the effect of the fundamental RF power couplers of the main linac SRF cavities on the beam using the ACE3P software package. The cavities in the ERL main linac will be operated at very high loaded quality factors of up to 6.5·10⁷, corresponding to a full bandwidth of only 20 Hz. Cavity microphonics will detune the cavities by more than one bandwidth during operation, thereby causing a time dependent change of the coupler kick in addition to its fast oscillation at the RF frequency. In order to investigate the dependence of the coupler kick on the cavity frequency, we calculate the coupler kick given to the beam for the case of a detuned RF cavity. We show that a compensation stub geometry located opposite to the input coupler port can be optimized to reduce the overall kick given to the beam and the emittace growth caused by its time dependence.

MOPC114

Design, Fabrication and Testing of Medium-Beta 650 MHz SRF Cavity Prototypes for Project-X

cavity, SRF, electron, vacuum

343

F. Marhauser, W.A. Clemens, J. Henry, P. Kneisel, R. Martin, R.A. Rimmer, G. Slack, L. Turlington, R.S. Williams
JLAB, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
A new type of superconducting radio frequency (SRF) cavity shape with a shallow equator dome to reduce electron impact energies for suppressing multipacting barriers has been proposed. The shape is in consideration for the first time in the framework of Project-X to design a potential multi-cell cavity candidate for the medium-beta section of the SRF proton CW linac operating at 650 MHz. Rationales covering the design of the multi-cell cavity, the manufacture, post-processing and high power testing of two single-cell prototypes are presented.

MOPC121

Design of Low-frequency Superconducting Spoke Cavities for High-velocity Applications

cavity, impedance, HOM, superconductivity

364

J.R. Delayen, C.S. Hopper
ODU, Norfolk, Virginia, USA
R.G. Olave
Old Dominion University, Norfolk, Virginia, USA

Superconducting single- and multi-spoke cavities have been designed to-date for particle velocities from β~0.15 to β~0.65. Superconducting spoke cavities may also be of interest for higher-velocity, low-frequency applications, either for hadrons or electrons. We present the design of 325 and 352 MHz spoke cavities optimized for β=0.8 and β=1.

MOPC123

Temperature Dependent Microphonics in the BNL Electron Cooler*

resonance, cavity, electron, cryogenics

370

P. Jain
Stony Brook University, Stony Brook, USA
I. Ben-Zvi, C. Schultheiss
BNL, Upton, Long Island, New York, USA

An R&D Energy Recovery Linac (ERL), to be used in the BNL electron cooler, has been operational in a developmental setting. The ERL requires a cryogenic system to supply cooling to a superconducting RF gun and the 5-cell superconducting RF cavity system that is kept cold at 2K. The 2K superfluid bath is produced by pumping on the bath using a sub-atmospheric warm compression system. During a test run in October 2010, a resonance peak corresponding to a noise of 30 Hz was observed at 1.88K. This noise peak, present at all temperatures below 2K, is assumed to be of mechanical origin from the vibration of the cryopump. Another resonance noise peak of 16 Hz, characteristic of the system, was observed at 1.98K, which shifted towards the 30 Hz peak as the temperature of the cryostat varied from 1.98K to 1.88K. The 16 Hz resonance peak upon hitting the 30 Hz resonance peak, sets a resonance condition, thereby the 30 Hz peak getting amplified by more than five times. In this paper we explore the origin of the temperature dependent 16 Hz resonance peak and give a physical explanation of the resonance.

MOPC126

High Power RF System for TRIUMF E-Linac Injector

cavity, klystron, TRIUMF, cryomodule

373

A.K. Mitra, Z.T. Ang, S. Calic, S.R. Koscielniak, R.E. Laxdal, R.W. Shanks, Q. Zheng
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada

TRIUMF has been funded to build the first stage of an electron linac with a final energy of 50 MeV and 500 kW beam power. The e-linac consists of an injector section with electron gun with 650 MHz rf modulated grid, a room temperature 1.3 GHz buncher cavity, and injector cryomodule, and two main-linac cryomodules for the accelerating section to be installed sequentially. The injector module has one 9 cell cavity whereas each of the accelerating cryomodules contains two 9-cell SC cavities. The injector cryomodule will be fed by a 30 kW cw Inductive Output Tube (IOT)and the accelerating cryomodule will be powered by a cw klystron. A first goal is a beam test of the e-Linac injector to 10MeV in 2012. Installation and full rated output power tests of the IOT on a 50 ohms load have been carried out. The IOT is purchased from CPI, USA while the transmitter is sourced from Bruker BioSpin. A power coupler conditioning station utilizes the same IOT. The buncher cavity is driven from a Bruker 600W amplifier. In this paper, the conceptual design of the e-Linac rf system will be summarized and the high power rf system for the injector including IOT measurement results will be presented.
SC stands for superconducting

MOPC128

16 kW Upgrade of the 1.3 GHz ELBE RF-system (CW) with Solid State Amplifiers

klystron, rf-amplifier, cavity, superconducting-cavity

379

H. Büttig, A. Arnold, A. Büchner, M. Justus, M. Kuntzsch, U. Lehnert, P. Michel, R. Schurig, G.S. Staats, J. Teichert
HZDR, Dresden, Germany

The superconducting CW- LINAC of the radiation source ELBE is in permanent operation since May 2001. In 2011 an upgrade program of ELBE is in progress to support additional applications. One part of the program is to double the RF-power per cavity to at least 16 kW. We first tested a 30 kW IOT-based amplifier (Bruker /CPI) at a cavity, later two 10 kW solid state amplifiers in parallel. The best solution found is based on 10 kW Solid State Power Amplifiers (SSPA) developed by Bruker BioSpin. The poster gives an overview on the status, the activities around this RF-upgrade project and the technical specification of the “turnkey” SSPA , designed for 10 kW, 1.3 GHz and full CW-operation.

MOPC129

Compact Solid State RF-Modules for Direct Drive RF-linacs

impedance, vacuum, cavity, klystron

382

R. Irsigler, M. Back, R. Baumgartner, O. Heid, T.J.S. Hughes, M. Kaspar, T. Kluge, J. Sirtl, K. Weidner, M. Zerb
Siemens AG, Erlangen, Germany

We present a modular RF power source concept based on solid state RF-modules with novel SiC transistors. The concept offers lower cost, better reliability and reduced maintenance compared to traditional RF-source technology. No circulators are required, which makes the RF-module very compact and reliable. The SiC power transistor has a very low input capacitance and was optimized for low gate resistance to enable fast switching in the VHF range. It delivers a maximum pulsed drain saturation current of 65 A. The transistor provides at 350 V supply voltage and 150 MHz an output power of 5,6 kW at a gain of 15,8 dB. It is essential to avoid high parasitic source inductances at RF and good thermal conductivity is required for operation at high duty cycle. We have built very compact 75 x 90 mm ceramic amplifier modules using a planar interconnect technology (SIPLIT) to connect the bare die transistors to the DCB substrate. The modules have a fully symmetric push-pull topology (circlotron) with four transistors in parallel in each leg. The RF-modules delivered at 150 MHz an impressive RF output power in the range of 40 kW. Further tests at 324 MHz are planned and will be presented.

MOPC135

IFMIF-EVEDA RF Power System

controls, power-supply, LLRF, cavity

394

D. Regidor, A. Arriaga, J.C. Calvo, A. Ibarra, I. Kirpitchev, J. Molla, P. Méndez, A. Salom, M. Weber
CIEMAT, Madrid, Spain
M. Abs, B. Nactergal
IBA, Louvain-la-Neuve, Belgium
P.-Y. Beauvais, M. Desmons, A. Mosnier
CEA/DSM/IRFU, France
P. Cara
Fusion for Energy, Garching, Germany
S.J. Ceballos, J. de la Cruz
Greenpower Technologies, Sevilla, Spain
Z. Cvetkovic, Z. Golubicic, C. Mendez
TTI, Santander, Spain
J.M. Forteza, J.M. González, C.R. Isnardi
Indra Sistemas, San Fernando de Henares, Spain
D. Vandeplassche
SCK-CEN, Mol, Belgium

The IFMIF/EVEDA Accelerator Prototype will be a 9 MeV, 125 mA CW deuteron accelerator to validate the technical options for the IFMIF accelerator design. The Radiofrequency Quadrupole (RFQ), buncher cavities and Superconducting Radiofrequency Linac (SRF Linac) require continuous wave RF power at 175 MHz with an accuracy of ±1% in amplitude and ±1° in phase. Also the IFMIF/EVEDA RF Power System has to work under pulsed mode operation (during the accelerator commissioning). The IFMIF/EVEDA RF Power System is composed of 18 RF power generators feeding the eight RFQ couplers (200 kW), the two buncher cavities (10⁵ kW) and the eight superconducting half wave resonators of the SRF Linac (10⁵ kW). The main components of each RF power chain are the Low Level Radio Frequency system (LLRF), three amplification stages and a circulator with its load. For obvious standardization and scale economies reasons, the same topology has been chosen for the 18 RF power chains: all of them use the same main components which can be individually tuned to provide different RF output powers up to 200 kW. The studies and the current design of the IFMIF/EVEDA RF Power System are presented in this contribution.

MOPC136

The RF Power Source for the High Beta Elliptical Cavities of the ESS Linac

klystron, cavity, neutron, LLRF

397

K. Rathsman, H. Danared, R. Zeng
ESS, Lund, Sweden
A.J. Johansson
Lund University, Lund, Sweden
C. Lingwood
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
R.J.M.Y. Ruber
Uppsala University, Uppsala, Sweden
C. de Almeida Martins
IST-UTL, Lisbon, Portugal

The European Spallation Source is an intergovernmental project building a multidisciplinary research laboratory based upon the world’s most powerful neutron source. The main facility will be built in Lund, Sweden. Construction is expected to start around 2013 and the first neutrons will be produced in 2019. The ESS linac delivers 5 MW of power to the target at 2.5 GeV, with a nominal current of 50 mA. The 120 high beta elliptical cavities, which operate at a frequency of 704 MHz and accelerate protons from 600 MeV to 2.5 GeV, account for more than half of the total number of rf cavities in the ESS linac and three quarter of the total beam power needed. Because of the large number of rf power sources and the high power level needed, all the design and development efforts for the rf power source have so far been focused on this part of the accelerator. The design and development status of the rf power source is reported in this paper with emphasis on reliability, maintainability, safety, power efficiency, investment cost and production capacity.

MOPC137

Medium Power 352 MHz Solid State Pulsed RF Amplifiers for the CERN Linac4 Project

controls, cavity, rf-amplifier, shielding

400

J.C. Broere, J. Marques Balula
CERN, Geneva, Switzerland
Y. Gomez
LPSC, Grenoble Cedex, France
M. Rossi
DBE, Padova, Italy

Economic, modular and highly linear pulsed RF amplifiers have recently been developed to be used for the three Buncher cavities in the CERN Linac4. The amplifiers are water cooled and can provide up to 33 kW pulsed RF power, 1.5 msec pulse length and 50 Hz repetition rate. Furthermore a 60 kWatt unit is under construction to provide the required RF Power for the Debuncher cavity. The concept is based on 1.2 kW RF power modules using the latest 6th generation LDMOS technology. For integration into the CERN control environment the amplifiers have an internal industrial controller, which will provide easy control and extended diagnostic functions. This paper describes the construction, performance, including linearity, phase stability and EMC compliance tests.

MOPC138

Practical Test of the Linac4 RF Power System

klystron, cavity, controls, electron

403

N. Schwerg, O. Brunner
CERN, Geneva, Switzerland

Linac4 is a linear accelerator for negative Hydrogen ions which will replace the old Linac2 as injector for the CERN accelerators. Its higher energy of 160 MeV will increase the beam intensity in the downstream machines. The normal-conducting accelerating structures are housed in a 100 m long tunnel which will be connected to the existing chain of accelerators and can be extended into a new injector chain. The high RF power for the Linac4 accelerating structures will be generated by thirteen 1.3 MW klystrons, previously used for the CERN LEP accelerator, and six new klystrons of 2.8 MW all operating at a frequency of 352.2 MHz. The re-use of existing LEP equipment, space limitations in the installation and tight phase and amplitude constraints pose a number of challenges for the integration of the RF power system. The power distribution scheme features a folded magic-tee feeding the power from a 2.8 MW klystron to two LEP circulators. We present first results from the Linac4 test place, validating the approach and the used components as well as reporting on the klystron re-tuning activities.

MOPC142

25 Year Performance Review of the SLAC 5045 S-Band Klystron

klystron, high-voltage, cathode, linear-collider

409

A. Jensen, A.S. Beebe, M.V. Fazio, A.A. Haase, E.N. Jongewaard, C. Pearson, D.W. Sprehn, A.E. Vlieks, L.E. Whicker
SLAC, Menlo Park, California, USA

Funding: This work was supported by the U.S. Department of Energy under contract DE-AC03-76SF00515.
The SLAC 5045 S-band klystron has proven to be a remarkably reliable high peak power tube. Originally developed in the 1980’s as an upgraded RF power source for the Stanford Linear Collider, it has continually powered the SLAC linac in support of numerous programs in particle physics and photon science. The large number of tubes built and operated (more than 800) coupled with accumulated running statistics over the last 25+ years represents an unprecedented wealth of operational experience for high pulse power klystrons in accelerator applications. Mean time between failures has continued to rise during this period and is frequently in excess of 100,000 hours during the last several years. Lifetime statistics as well as some important failure modes are presented and examined here.

MOPC146

Development of Timing Distribution System with Femto-second Stability

feedback, controls, acceleration, laser

421

T. Naito, K. Ebihara, S. Nozawa, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan
M. Amemiya
AIST, Tsukuba, Japan

A timing distribution system with femto-second stability has been developed for the RF synchronization of accelerator and the laser synchronization of the pump-probe experiments. The system uses a phase stabilized optical fiber(PSOF) and an active fiber length stabilization. The PSOF has 5 ps/km/degC of the temperature coefficient. The active fiber length stabilization uses the phase detection of the round-trip sinusoidal wave and the fiber stretcher for the compensation of the fiber length. In this paper, we present the test results on a 500 m long signal distribution. The preliminary results of the timing stability are 20 fs at several minutes and 100 fs at four days, respectively.

MOPC151

Design and Commissioning of a Multi-frequency Digital Low Level RF Control System*

cavity, controls, low-level-rf, superconducting-cavity

433

M. Konrad, U. Bonnes, C. Burandt, J. Conrad, R. Eichhorn, J. Enders, P.N. Nonn, N. Pietralla
TU Darmstadt, Darmstadt, Germany

Funding: Work supported by DFG through CRC 634 and by the BMBF under 06 DA 9024 I.
Triggered by the need to control the superconducting cavities of the S-DALINAC, which have a high loaded quality factor and are thus very susceptible to microphonics, the development of a digital low level RF control system was started. The chosen design proved to be very flexible since other frequencies than the original 3 GHz may be adapted easily: The system converts the RF signal coming from the cavity (e. g. 3 GHz) down to the base band using a hardware I/Q demodulator. The base band signals are digitized by ADCs and fed into a FPGA where the control algorithm is implemented. The resulting signals are I/Q modulated before they are sent back to the cavity. The superconducting cavities are operated with a self-excited loop algorithm whereas a generator-driven algorithm is used for the low Q normal-conducting bunching cavities. A 6 GHz RF front end allows the synchronous operation of a new 2f buncher at the S-DALINAC. Meanwhile, a 325 MHz version has been built to control a pulsed prototype test stand for the p-LINAC at FAIR. We will present the architecture of the RF control system as well as results obtained during operation.

MOPC152

Digital Control System for Solid State Direct Drive™ RF-Linacs

controls, cavity, LLRF, pick-up

436

J. Sirtl, M. Back, T. Kluge
Siemens AG, Erlangen, Germany
H. Schröder
ASTRUM IT GmbH, Erlangen, Germany

The Solid State Direct Drive™ concept for RF linacs has previously been introduced*. Due to the different methodology (i.e. solid state based rather than electron tube based) as compared with conventional RF sources a new control system is required to deliver the required LLRF. To support this new technology a fully digital control system for this new concept has been developed. Progresses in Digital – Analogue Converter technology and FPGA technology allows us to create a digital System which works in the 150 Mhz baseband. The complete functionality was implemented in a Virtex 6 FPGA. Dispensing with the PLL allows an excellent jitter-behaviour. For this job, we use three 12 bit ADCs with a Sampling Rate of 1 GS/s and two 16 bit DACs (1 GS/s). The amplitude of the RF source is controlled by dividing the RF modules mounted on the power combiner** into two groups and controlling the relative phase of each group (in effect mimicking an “out-phasing” amplifier). This allows the modules to be operated at their optimum working point and allows a linear amplitude behaviour.
* O. Heid, T. Hughes, Proc. of IPAC10, THPD002, p. 4278, Kyoto, Japan (2010).
** O. Heid, T. Hughes, Proc. of LINAC10, THPD068, Tsukuba, Japan.

MOPC156

Operation Test of Distributed RF System with Circulator-less Waveguide Distribution in S1-Global Project at STF/KEK

cavity, klystron, feedback, superconducting-cavity

448

T. Matsumoto, M. Akemoto, D.A. Arakawa, S. Fukuda, H. Honma, E. Kako, H. Katagiri, S. Matsumoto, H. Matsushita, S. Michizono, T. Miura, H. Nakajima, K. Nakao, T. Shidara, T. Takenaka, Y. Yano, M. Yoshida
KEK, Ibaraki, Japan

Distributed RF System (DRFS) is one candidate for a single main linac tunnel design of International International Linear Collider (ILC). In the DRFS, more than ten 800-kW klystrons having a modulating anode are operated by a common DC power and a modulation anode modulator. Each klystron feeds its power into two superconducting cavities and its waveguide distribution system is configured without circulators. This DRFS consists of four SC cavities, two klystrons and a modulator was demonstrated in S1-Global project. The results of circulator-less operation in the DRFS will be reported.

MOPC158

RF Capture of a Beam with Charge-exchanging Multi-turn Injection

injection, simulation, acceleration, closed-orbit

454

T. Uesugi, Y. Ishi, Y. Kuriyama, J.-B. Lagrange, Y. Mori, R. Nakano, T. Planche, B. Qin, E. Yamakawa
KURRI, Osaka, Japan
Y. Niwa, K. Okabe, I. Sakai
University of Fukui, Faculty of Engineering, Fukui, Japan

Funding: This work was supported by MEXT of Japan in the framework of a task entitled ”Research and Development for an Accelerator-Driven Sub-critical System Using an FFAG Accelerator”.
In the fixed field alternating gradient (FFAG) synchrotron in Kyoto university research reactor Institute (KURRI), charge exchange injection was adopted since 2011. The charge stripping foil is located on the closed orbit of the injection energy, and no bump orbit system is used. Instead, the injected beam escapes from the stripping foil according to the closed-orbit shift due to acceleration. In this scheme, it is important to minimize the number of foil hitting, which causes emittance growth and foil heating. In this paper, the rf capture is studied by means of simulation.

MOPC161

Challenges for the Low Level RF Design for ESS

cavity, LLRF, controls, klystron

460

A.J. Johansson
Lund University, Lund, Sweden
R. Zeng
ESS, Lund, Sweden

The European Spallation Source (ESS) is a planned neutron source to be built in Lund, Sweden, which is planned to produce the first neutrons in 2019. It will have an average beam power at the target of 5 MW, an average current along the Linac of 50 mA, and a pulse repetition rate and length of 20 Hz and 2 ms, respectively. The Linac will have around 200 LLRF stations employed to control a variety of RF cavities such as RFQ, DTL, spoke and elliptical superconducting cavities. The challenges on LLRF systems are mainly the high demands on energy efficiency on all parts of the facility, an operational goal of 95% availability of the facility and a comparably short time from start of final design to commissioning. Running with long pulses, high current and spoke cavities also brings new challenges on LLRF design. In this paper we will describe the consequences these challenges have on the LLRF system, and the proposed solutions and development projects that have started in order to reach these demands.

MOPC165

Digital Low Level RF Development at Daresbury Laboratory

cavity, controls, LLRF, beam-loading

469

P.A. Corlett, L. Ma, A.J. Moss
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Digital LLRF development using Field Programmable Gate Arrays (FPGAs) is a new activity at Daresbury Laboratory. Using the LLRF4 development board, designed by Larry Doolittle of Lawrence Berkeley National Laboratory, a full featured control system incorporating fast feedback loops and a feed-forward system has been developed for use on the ALICE (Accelerators and Lasers in Combined Experiments) energy recovery linac. Technical details of the system are presented, along with experimental measurements.

MOPC166

Low RF Control Feedback and IQ Vector Modulator Compensation Functions

controls, gun, feedback, coupling

472

M.G. Fedurin, R. Malone, V. Yakimenko
BNL, Upton, Long Island, New York, USA

IQ vector modulator is key element of the gun and linac RF control circuits at Accelerator Test Facility at Brookhaven National Laboratory. IQ modulator calibration procedure was developed to find proper compensation functions in the conversion algorithm to minimize phase-amplitude coupling and setting-reading errors: rms(A_set - A_read )= 0.03dB, rms(Phi_set - Phi_read) = 0.3 deg. Since stabilization of the RF phase and amplitude is become critical for many experiments the slow feedback was developed and applied as well to significantly compensate drifts in RF system.

MOPO023

Laser-based Alignment System at the KEKB Injector Linac

laser, alignment, vacuum, injection

529

M. Satoh, N. Iida, T. Suwada
KEK, Ibaraki, Japan
K. Minoshima, S. Telada
AIST, Tsukuba, Japan

A laser-based alignment system is under development at the 500-m-long KEKB injector linac. The original system was designed and constructed more than thirty-years ago, and thus, we are revisiting our alignment system because the previous alignment system has become too obsolete. The new alignment system is again strongly required for the next generation SuperKEKB project. The new laser alignment system is similar to the previous one, which comprises a helium-neon laser and quadrant photodetectors installed in vacuum light pipes. A girder displacement of the accelerating structure can be precisely measured in the direction of the laser-ray trace, where the laser light must stably propagate up to 500-m downstream without any orbital and beam-size fluctuation. We tested the laser-ray propagation and the stability along a 100-m-long beam line under a vacuum condition of 0.1-1 Torr. In this paper, we will report the system description and test results in detail.

MOPO025

Experimental Study on New Laser-based Alignment System utilizing a Sequential Three-point Method at the KEKB Injector Linac

laser, alignment, focusing, factory

532

T. Suwada, M. Satoh
KEK, Ibaraki, Japan
K. Minoshima, S. Terada
AIST, Tsukuba, Japan

A new laser-based alignment system is under development in order to precisely align accelerator components along an ideal straight line at the 600-m-long KEKB injector linac. A well-known sequential three-point method with Fresnel lenses and a CCD camera is revisited in a preliminary design of the new alignment system. The new alignment system is strongly required in order to stably accelerate high-brightness electron and positron beams with high bunch charges and also to keep the beam stability with higher quality towards the Super B-factory at KEK. A new laser optics has been developed and the laser propagation characteristics has been systematically investigated at a 200-m-long straight section at atmospheric pressure. In this report, the preliminary experimental results are reported along with the basic design of the new laser-based alignment system.

MOPO030

Theoretical and Practical Feasibility Demonstration of a Micrometric Remotely Controlled Pre-alignment System for the CLIC Linear Collider

alignment, simulation, target, controls

547

H. Mainaud Durand, M. Anastasopoulos, N.C. Chritin, J. Kemppinen, M. Sosin, S. griffet
CERN, Geneva, Switzerland
T. Touzé
ENSTA, Brest, France

The active pre-alignment of the Compact Linear Collider (CLIC) is one of the key points of the project: the components must be pre-aligned w.r.t. to a straight line within a few microns over a sliding window of 200 m, along the two linacs of 20 km each. The proposed solution consists of stretched wires of more than 200 m, overlapping over half of their length, which will be the reference of alignment. Wire Positioning Sensors (WPS), coupled to the supports to be pre-aligned, will perform precise and accurate measurements within a few microns, w.r.t. these wires. A micrometric fiducialisation of the components and a micrometric alignment of the components on common supports will make the strategy of pre-alignment complete. In this paper, the global strategy of active pre-alignment is detailed and illustrated by the latest results demonstrating the feasibility of the proposed solution.

MOPO041

Preliminary Testing of TPS Timing System

controls, gun, booster, EPICS

574

C.Y. Wu, Y.-T. Chang, J. Chen, Y.-S. Cheng, P.C. Chiu, K.T. Hsu, K.H. Hu, C.H. Kuo, C.-Y. Liao
NSRRC, Hsinchu, Taiwan

The timing system of Taiwan Photon Source (TPS) provides synchronization for electron gun, modulators of linac, pulse magnet power supplies, booster power supply ramp, bucket addressing of storage ring, diagnostic equipments, beamline gating signal for top-up injection. The timing system utilizes a central event generator to generate events and distribute them over optic fiber network, and decodes them at the event receivers. The system supports uplink functionality which will be used for the fast interlock system to distribute signals like beam dump and post-mortem trigger. The timing system has now been in operation for Linac of TPS. This paper presents prototype for the timing system of TPS.

MOPS019

High Intensity Longitudinal Dynamics Studies for Higher Energy Injection into the ISIS Synchrotron

injection, simulation, bunching, space-charge

640

R.E. Williamson, D.J. Adams, C.M. Warsop
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

ISIS is the world’s most productive pulsed neutron and muon source, at the Rutherford Appleton Laboratory in the UK. Operation is centred on a loss-limited 50 Hz proton synchrotron which accelerates 3·10¹³ protons per pulse from 70 MeV to 800 MeV, delivering a mean beam power of 0.2 MW. Present studies on ISIS upgrades are focussed on a new linac for higher energy injection into the existing ring, potentially increasing beam current through reduction in space charge and optimized injection. Studies assume injection of a chopped beam at 180 MeV and offer the possibility of beam powers in the 0.5 MW regime. A critical aspect of such an upgrade is the longitudinal dynamics, associated RF parameters, space charge levels and stringent requirements on beam loss. This paper outlines studies optimizing longitudinal parameters including key design requirements such as bunching factor and satisfying the Keil-Schnell-Boussard stability criterion throughout acceleration. Work developing and benchmarking the in-house longitudinal dynamics code used for these studies is also summarized.

MOPS026

Start-to-end Beam Dynamics Simulations for the Prototype Accelerator of the IFMIF/EVEDA Project

rfq, simulation, quadrupole, solenoid

655

N. Chauvin
CEA/IRFU, Gif-sur-Yvette, France
M. Comunian
INFN/LNL, Legnaro (PD), Italy
O. Delferrière, R.D. Duperrier, R. Gobin, A. Mosnier, P.A.P. Nghiem, D. Uriot
CEA/DSM/IRFU, France
C. Oliver
CIEMAT, Madrid, Spain

The EVEDA (Engineering Validation and Engineering Design Activities) phase of the IFMIF (International Fusion Materials Irradiation Facility) project consists in building, testing and operating a 125 mA/9 MeV prototype accelerator in Rokkasho-Mura (Japan). Because of high beam intensity and power, the different sections of the accelerator (injector, RFQ, MEBT, Superconducting Radio-Frequency linac and HEBT) have been optimized with the twofold objective of minimizing losses along the machine and keeping a good beam quality. Extensive start-to-end multi-particles simulations have been performed to validate the prototype accelerator design. A Monte Carlo error analysis has been carried out to study the effects of misalignments and field variations. In this paper, the results of theses beam dynamics simulations, in terms of beam emittance, halo formation and beam losses, are presented.

MOPS027

Stability Charts for the IFMIF SRF-Linac

emittance, resonance, SRF, space-charge

658

W. Simeoni, N. Chauvin
CEA/IRFU, Gif-sur-Yvette, France
A. Mosnier, P.A.P. Nghiem, D. Uriot
CEA/DSM/IRFU, France

Among the most recent projects, the IFMIF-EVEDA accelerators break the record of high intensity, leading to a multi-MW beam power at relatively low energy. The concern for such accelerated beams is the predominance of the self-field energy upon the beam energy. In these conditions, the space charge effect is at its maximum, which triggers different nonlinear mechanisms implying emittance growth, halo formation and sudden particle lost. In this proceeding we show the stability charts constructed for the IFMIF SRF-Linac, with which are identified the collective space charge resonances responsible of transverse-longitudinal emittance exchange and emittance growth.

MOPS028

An Ion Beam Matching to a Linac Accelerating-focusing Channel

rfq, ion, emittance, simulation

661

A. Orzhekhovskaya, W.A. Barth, G. Clemente, L.A. Dahl, P. Gerhard, L. Groening, M. Kaiser, M.T. Maier, S. Mickat, B. Schlitt, H. Vormann, S.G. Yaramyshev
GSI, Darmstadt, Germany
U. Ratzinger
IAP, Frankfurt am Main, Germany

Funding: Work supported by HIC for FAIR
A modern linear accelerator of ions is a long chain of different accelerating-focusing structures. The design of new linacs, as well as an upgrade and optimization of operating facilities, requires precise and reliable beam matching with the subsequent sections. Proper matching of the beam to the channel allows to improve the performance of the whole linac and to reduce the specific costs. Additionally it helps to avoide particle loss in high energy high intensity linacs. Generally a matching algorithm combines precisely measured or calculated accelerating-focusing external fields and experimentally obtained details of the beam parameters with an advanced code for beam dynamics simulations including space charge effects. Experimental results are introduced into a code as input data. The described algorithm has already been successfully implemented for several GSI projects: an upgrade of the GSI heavy ion linac UNILAC, an ion linac for the cancer therapy, the proton linac for the FAIR facility, a facility for laser acceleration of ions and others. Measured data and results of beam dynamics simulations leading to an achieved improvement of the linac performance are presented.

MOPS030

Beam Dynamics of the FRANZ Bunch Compressor using Realistic Fields with a Focus on the Rebuncher Cavities

cavity, dipole, simulation, focusing

667

D. Noll, L.P. Chau, M. Droba, O. Meusel, H. Podlech, U. Ratzinger, C. Wiesner
IAP, Frankfurt am Main, Germany

Funding: Work supported by HIC for FAIR.
The ARMADILLO bunch compressor currently being designed at IAP is capable of reaching a longitudinal pulse compression ratio of 45 for proton beams of 150 mA at 2 MeV. It will provide one nanosecond proton pulses with a peak current of 7.7 A. The system guides nine linacμbunches deflected by a 5 MHz rf kicker and uses four dipole magnets - two homogeneous and two with field gradients - to merge them on the target. For longitudinal focusing and an energy variation of ±200 keV two multitrack rf cavities are included. ARMADILLO will be installed at the end of the Frankfurt Neutron Source FRANZ making use of the unique 250 kHz time structure. This contribution will provide an overview of the layout of the system as well as recent advances in component design and beam dynamics of the compressor.

MOPS033

Beam Dynamics Studies on the 100 MeV/100 kW Electron Linear Accelerator for NSC KIPT Neutron Source

electron, dipole, gun, simulation

673

S. Pei, Y.L. Chi, M. Hou, W.B. Liu, G. Pei, S.H. Wang, Z.S. Zhou
IHEP Beijing, Beijing, People's Republic of China
N. Aizatsky, I.M. Karnaukhov, V.A. Kushnir, V. Mitrochenco, A.Y. Zelinsky
NSC/KIPT, Kharkov, Ukraine

We designed one 100MeV/100kW electron linear accelerator for NSC KIPT, which will be used to drive a neutron source on the base of subcritical assembly. Beam dynamics studies has been conducted to reach the design requirement (E=100MeV, P=100kW, dE/E<1% for 99% particles). In this paper, we will present the progress of the design and dynamics simulation results. For high intensity and long beam pulse linear accelerators, BBU effect is one big issue; special care has been taken in the accelerating structure design. To satisfy the energy spread requirement at the linac exit, the particles with large energy difference from the synchronous particle should be eliminated at low energy stage to ease the design of the collimation system and radiation shielding. A dispersion free chicane with 4 bending magnets is introduced at the downstream of the 1st accelerating section; the unwanted particles will be collimated there.

MOPS035

Energy Spreads by Transient Beam Loading Effect in Pulsed RF Linac

gun, electron, bunching, beam-loading

679

S.H. Kim, M.-H. Cho, G. Ha, H.R. Yang
POSTECH, Pohang, Kyungbuk, Republic of Korea
W. Namkung, S.J. Park
PAL, Pohang, Kyungbuk, Republic of Korea
J.-S. Oh
NFRI, Daejon, Republic of Korea

Funding: Work partly supported by KAPRA and POSTECH Physics BK21 Program
RF linacs for high power beams are operated in the fully beam-loaded condition for the power efficiency. In this condition, temporal energy spreads are induced by the transient beam loading effect. Irradiation sources require the beam energy of less than 10 MeV to prevent undesirable neutron production. In order to maximize the beam power and maintain the beam energy in a safe value, we need to suppress the temporal energy spreads. In an L-band traveling-wave linac for irradiation sources, the high energy electrons are suppressed by the beam current modulation with the RF power modulation. As a result, the average beam energy and the corresponding beam power are improved by nearly 60% compared to the case without any modulations.

MOPS037

High Intensity Transient Beam Dynamic Study in Travelling Wave Electron Accelerators with Accounting of Beam Loading Effect

simulation, beam-loading, space-charge, electron

682

S.M. Polozov, T.V. Bondarenko, E.S. Masunov, V.I. Rashchikov, A.V. Voronkov
MEPhI, Moscow, Russia

The beam loading effect is one of main problems limiting the beam current. The methods of beam dynamic simulation taking into account the beam loading effect were discussed previously. Simulation methods and the especial code version BEAMDULAD-BL was described in the paper*. The beam loading effect was considered only for traveling wave linacs and for stationary beam only. Now it is important to study the beam dynamics of short current pulses, i.e. for transient process. We can consider only one beam bunch (or a packet of bunches) in a long external RF field pulse in stationary case. The beam radiation and wave fields can be calculated in the quasi-statically approximation. This approximation can not be used for transient mode. The methods of beam dynamics simulation will be discussed in this paper for transient mode. New code version BEAMDULAC-BLNS will be described. The simple test simulations will be carried out.
* A.V. Voronkov et al., "Beam Loading Effect of High Current Trawling Wave Accelerator Dynamic Study", Proc. of IPAC’10, Kyoto, Japan, TUPEA012, p. 1348 (2010).

MOPS038

3D Beam Dynamic Simulation in Heavy Ion Superconducting Drift Tube Linac

cavity, simulation, focusing, ion

685

A.V. Samoshin, S.M. Polozov
MEPhI, Moscow, Russia

The superconducting (SC) linac conventionally consists of some different classes of the identical cavities. Each cavity is based on a SC structure with a high accelerating gradient. The low charge state beams require stronger transverse focusing. This focusing can be reached with the help of SC solenoid lenses. In this paper beam dynamics simulation obtain by smooth approximation and full field. Traditionally only the Coulomb field is taken into account for low energy beams. In this paper the computer simulation of heavy ion beam dynamics in superconducting (SC) linac will carried out by means of the "particle-in-cell" method. Simulation results will present.

MOPS040

Intra-Bunch Energy Spread of Electrons in Powerful RF Linacs for Nuclear Physics Research*

target, electron, HOM, simulation

691

V.V. Mytrochenko, M.I. Ayzatskiy, V.A. Kushnir, A. Opanasenko, S.A. Perezhogin, V.L. Uvarov
NSC/KIPT, Kharkov, Ukraine

Funding: Ukrainian State program of fundamental and applied studies on the use of nuclear materials, nuclear and radiation technologies in the fields of economics (YaMRT project No. 826/35)
There are some particles in RF electron linacs with energy that may be significantly different from that of particles within a core of the bunch. Loss of these particles at average beam power of tens of kilowatts can cause radiation and thermal problems. Filtration of such particles during the initial stage of acceleration, at energies below the threshold of photonuclear reactions, is important. The paper analyzes several ways to perform such type of filtration in the injector part of a powerful electron linac using a RF chopper or magnetic systems.

MOPS047

Studies of Transverse Single-pass Beam Breakup in E-Linac

HOM, cavity, dipole, emittance

706

D. Kaltchev, R.A. Baartman, Y.-C. Chao, P. Kolb, S.R. Koscielniak, L. Merminga, A.K. Mitra, V. Zvyagintsev
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada

Time-domain simulations of single-pass transverse beam-breakup (BBU) effects in E-linac are described. We use dipole-HOM parameters for the 9-cell cavity obtained with Particle Studio to evaluate the rms bunch orbit offsets at linac exit. Finding the multi-bunch orbit contribution to machine emittance as a function of the average beam current allows to evaluate the performance of two cavity models for two different modes of machine operation.

MOPS051

Modeling of the Beam Break Up Instability for BERLinPro*

cavity, optics, solenoid, HOM

718

Y. Petenev, A.V. Bondarenko, A.N. Matveenko
HZB, Berlin, Germany

Following funding approval late 2010, Helmholtz-Zentrum Berlin officially started Jan. 2011 the design and construction of the Berlin Energy Recovery Linac Project BERLinPro. The initial goal of this compact ERL is to develop the ERL accelerator physics and technology required to accelerate a high-current low emittance beam. In this work the threshold current of the Beam Break Up (BBU) instability was calculated for the BERLinPro. The comparison of two 100 MeV linacs based on different type of superconducting cavities is made. Different methods of BBU suppression are investigated (e.g. the influence of solenoid, pseudo-reflector and quadruple triplets in the linac structure on the BBU threshold).

MOPS058

KEKB Linac Wakefield Studies of Comparing Theoretical Calculation, Simulation and Experimental Measurement*

emittance, wakefield, injection, simulation

739

L. Zang, N. Iida, Y. Ogawa, M. Satoh, M. Yoshida, D.M. Zhou
KEK, Ibaraki, Japan

For superKEKB, in order to achieve aiming luminosity machine need to run with a nano-beam scheme so that a small beam emittance is critical important. During the beam propagation, the short-range wake field in the accelerating structure will cause the beam instability and emittance growth. In practical, injecting beam with certain offset could compensate wakfield. And beam emittance could be measured by tuning the quadruple known as quadscan method. In this paper, wakefield theoretical calculation, simulation results will be presented. And then the wakefield impact to beam emittance and wakefield compensation will be discussed. Finally, we will show the comparison of the results getting from theoretical calculation and experimental measurement.

MOPS076

Long Range Wakefields in the SwissFEL C-band Linac

wakefield, HOM, simulation, impedance

781

A. Citterio, M. Aiba, R. Zennaro
PSI, Villigen, Switzerland

The SwissFEL main linac consists of more than hundred constant gradient C-band accelerating structures which boost the beam energy from 410 MeV at the injector to the final nominal energy of 5.8 GeV. With a repetition rate of 100 Hz, two bunches per pulse can be accelerated with a spacing of 28 ns to feed simultaneously two different FEL arms*. Rising of the long range wakefields, both longitudinal and transverse, could affect this multibunch operation, causing degenerative effects on the quality of the second bunch. A direct computation of the longitudinal and transverse wakes by means of time domain simulations is compared with a model based on the computation of the dispersion curves of the wake modes by frequency domain simulations. A good agreement is obtained for both the synchronous frequency and impedance of all the main modes contributing to the wakefields. Moreover, the total longitudinal wake at 28 ns is below the thighter tolerances required by the beam dynamics, so that neither Higher Order Modes (HOMs) either beam loading require compensation. The effects on the beam of the long range transverse wakefields are also negligeable.
*R. Ganter et al, SwissFEL CDR, PSI report n. 10-04; http://www.psi.ch/swissfel/CurrentSwissFELPublicationsEN/SwissFEL_CDR_{_}v19₀3.03.11-small.pdf

MOPS082

Some Considerations on the Choice of Frequency and Geometrical Beta in High Power Proton Linacs in the Context of Higher Order Modes

cavity, HOM, simulation, proton

793

M. Schuh, F. Gerigk
CERN, Geneva, Switzerland
M. Schuh
MPI-K, Heidelberg, Germany
C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Several high power superconducting (SC) proton linear accelerators are currently in the design stage around the world, such as for example the European Spallation Source (ESS) in Lund, Project X at Fermilab, the European ADS demonstrator MYRRAH in Mol and the Superconducting Proton linac (SPL) at CERN. In this contribution, the influence of Higher Order Modes (HOMs) in elliptical SC cavities is discussed as a function of the operation frequency, the number of cells and the geometrical beta of the cavity. Based on cavity design data beam dynamics simulations are executed for different linac layouts to quantify the influence of HOMs.

MOPS085

Wakefield Calculations for the LCLS in Multibunch Operation*

dipole, injection, HOM, FEL

802

K.L.F. Bane
SLAC, Menlo Park, California, USA

Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515.
Normally the Linac Coherent Light Source (LCLS) operates in single-bunch mode, sending a bunch of up to 250 pC charge at 120 Hz through the linac and the undulator, and the resulting FEL radiation into one of the experimental hutches. With two bunches per rf pulse, each pulse could feed either two experiments or one experiment in a pump-probe type configuration. Two-bunch FEL operation has already been briefly tested at the LCLS, and works reasonably well*, although not yet routinely. In this report we study the longitudinal and transverse long-range (bunch-to-bunch) wakefields of the linacs and their effects on LCLS performance in two-bunch mode. The longitudinal wake changes the average energy and chirp at the second bunch, and the transverse wake misaligns the second bunch (in transverse phase space) in the presence of e.g. transverse injection jitter or quad misalignments. Finally, we extend the study to consider the LCLS with trains of up to 20 bunches per rf pulse.
* F.-J. Decker et al, "A demonstration of multi-bunch operation in the LCLS," Proceedings of FEL2010, Malmoe, Sweden, p. 467.

MOPZ009

The Muon Linac for the International Design Study for the Neutrino Factory

cavity, cryomodule, factory, lattice

838

A. Kurup, M. Aslaninejad, C. Bonţoiu, J.K. Pozimski
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
K.B. Beard
Muons, Inc, Batavia, USA
S.A. Bogacz, V.S. Morozov
JLAB, Newport News, Virginia, USA

The first stage of muon acceleration in the Neutrino Factory utilises a superconducting linac to accelerate muons from 244 MeV to 900 MeV. The linac is split into three types of cryomodules with decreasing magnetic fields and increasing amounts of RF voltage but with the design of the superconducting solenoid and RF cavities being the same for all cryomodules. The current status of the muon linac for the International Design Study for the Neutrino Factory will be presented including a final lattice design of the linac; electromagnetic simulations; and a preliminary cost estimate.

MOPZ029

Aperture Windows in High-Gradient Cavities for Accelerating Low-Energy Muons

cavity, septum, target, vacuum

862

S.S. Kurennoy, A.J. Jason, W.M. Tuzel
LANL, Los Alamos, New Mexico, USA

A high-gradient linear accelerator for accelerating low-energy muons and pions in a strong solenoidal magnetic field has been proposed for homeland defense and industrial applications*. The acceleration starts immediately after collection of pions from a target in a solenoidal magnetic field and brings muons to a kinetic energy of about 200 MeV over a distance of the order of 10 m. At this energy, both ionization cooling of the muon beam and its further acceleration become feasible. A normal-conducting linac with external-solenoid focusing can provide the required large beam acceptances. The linac consists of independently fed zero-mode (TM010) RF cavities with wide beam apertures closed by thin conducting windows. The high gradients lead to significant heat deposition on the aperture windows. Here we explore options for the edge-cooled thin windows in the zero-mode cavities. Electromagnetic and thermal-stress computations are complemented by thermal-test experiments to select the best solution for the aperture windows.
* S.S. Kurennoy, A.J. Jason, H. Miyadera, “Large-Acceptance Linac for Accelerating Low-Energy Muons,” Proc. of IPAC10, p. 3518 (2010).

MOPZ031

Multipass Muon RLA Return Arcs based on Linear Combined-function Magnets

dipole, quadrupole, optics, lattice

868

V.S. Morozov, S.A. Bogacz, Y. Roblin
JLAB, Newport News, Virginia, USA
K.B. Beard
Muons, Inc, Batavia, USA

Funding: Supported in part by US DOE STTR Grant DE-FG02-08ER86351. Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Recirculating Linear Accelerators (RLA) are an efficient way of accelerating short-lived muons to the multi-GeV energies required for Neutrino Factories and TeV energies required for Muon Colliders. In this paper we present a design of a two-pass RLA return arc based on linear combined function magnets, in which both charge muons with momenta different by a factor of two are transported through the same string of magnets. The arc is composed of 60°-bending symmetric super cells allowing for a simple arc geometry closing. By adjusting the dipole and quadrupole components of the combined-function magnets, each super cell is designed to be achromatic and to have zero initial and final periodic orbit offsets for both muon momenta. Such a design provides a greater compactness than, for instance, an FFAG lattice with its regular alternating bends and is expected to possess a large dynamic aperture characteristic of linear-field lattices.

TUXA01

Status and Challenges of the China Spallation Neutron Source

DTL, power-supply, rfq, dipole

889

S. Fu, H. Chen, Y.W. Chen, Y.L. Chi, H. Dong, L. Dong, S.X. Fang, K.X. Huang, W. Kang, J. Li, L. Ma, H.F. Ouyang, H. Qu, H. Sun, J. Tang, C.H. Wang, Q.B. Wang, S. Wang, T.G. Xu, Z.X. Xu, X. Yin, C. Zhang, J. Zhang
IHEP Beijing, Beijing, People's Republic of China

The accelerator complex of China Spallation Neutron Source (CSNS) mainly consists of an H⁻ linac of 80 MeV and a rapid-cycling synchrotron of 1.6 GeV. It operates at 25 Hz repetition rate with an initial proton beam power of 100 kW and is upgradeable to 500kW. The project will start construction in the middle of 2011 with a construction period of 6.5 years. The CSNS accelerator is the first large-scale, high-power accelerator project to be constructed in China and thus we are facing a lot of challenges. This paper presents the current status of CSNS project and summarizes the technology development during the past several years.

Slides TUXA01 [3.444 MB]

TUOAA01

The EUROnu Project: A High Intensity Neutrino Oscillation Facility in Europe

target, factory, proton, acceleration

894

T.R. Edgecock
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
E.H.M. Wildner
CERN, Geneva, Switzerland

EUROnu is a European Commission funded FP7 Design Study investigating three possible options for a future high intensity neutrino oscillation facility in Europe. These options are a CERN to Frejus Super-Beam, a Neutrino Factory and a Beta Beam. The aims of the project are to undertake the crucial R&D on each of the accelerator facilities and determine their performance and relative cost, including the baseline detectors for each facility. A comparison will then be made and the results reported to the CERN Council as part of the CERN Strategy Review.

Slides TUOAA01 [7.638 MB]

TUOAA03

The Linac4 Project at CERN

DTL, cavity, rfq, klystron

900

M. Vretenar, L. Arnaudon, P. Baudrenghien, C. Bertone, Y. Body, J.C. Broere, O. Brunner, M.C.L. Buzio, C. Carli, F. Caspers, J.-P. Corso, J. Coupard, A. Dallocchio, N. Dos Santos, R. Garoby, F. Gerigk, L. Hammouti, K. Hanke, M.A. Jones, I. Kozsar, J.-B. Lallement, J. Lettry, A.M. Lombardi, L.A. Lopez Hernandez, C. Maglioni, S.J. Mathot, S. Maury, B. Mikulec, D. Nisbet, C. Noels, M.M. Paoluzzi, B. Puccio, U. Raich, S. Ramberger, C. Rossi, N. Schwerg, R. Scrivens, G. Vandoni, J. Vollaire, S. Weisz, Th. Zickler
CERN, Geneva, Switzerland

As the first step of a long-term programme aiming at an increase in the LHC luminosity, CERN is building a new 160 MeV H⁻ linear accelerator, Linac4, to replace the ageing 50 MeV Linac2 as injector to the Proton-Synchrotron Booster (PSB). Linac4 is an 86-m long normal-conducting linac made of an H⁻ source, a Radio Frequency Quadrupole (RFQ), a chopping line and a sequence of three accelerating structures: a Drift-Tube Linac (DTL), a Cell-Coupled DTL (CCDTL) and a Pi-Mode Structure (PIMS). The civil engineering has been recently completed, and construction of the main accelerator components has started with the support of a network of international collaborations. The low-energy section up to 3 MeV including a 3-m long 352 MHz RFQ entirely built at CERN is in the final construction phase and is being installed on a dedicated test stand. The present schedule foresees beam commissioning of the accelerator in the new tunnel in 2013/14; the moment of connection of the new linac to the CERN accelerator chain will depend on the LHC schedule for long shut-downs.

Slides TUOAA03 [10.347 MB]

TUYB03

CLIC Conceptual Design and CTF3 Results

emittance, target, damping, luminosity

961

D. Schulte
CERN, Geneva, Switzerland

An international collaboration is carrying out an extensive R&D programme to prepare CLIC, a multi-TeV electron-positron collider. In this concept, the colliding beams will be accelerated in very high gradient normal conducting 12 GHz accelerating structures. The necessary RF power is extracted from a high-current, low-energy drive beam that runs parallel to the colliding beams and is generated in a central complex. This year the collaboration will produce a conceptual design report to establish the feasibility of the technology. The CLIC concept will be introduced and the status of key studies of critical issues will be reviewed. A focus will be on the CLIC Test Facility 3 (CTF3), which is a test facility to produce and use high current a drive beam.

Slides TUYB03 [13.204 MB]

TUZB01

Superconducting RF Technology for Proton and Ion Accelerators

cavity, cryomodule, SRF, proton

966

G. Devanz
CEA/DSM/IRFU, France

The worldwide status of superconducting RF cavities and cryomodules for low velocity ion and proton particles is reviewed, with emphasis on the construction and tests of prototypes. A number of different multicell structures at a range of operating frequencies have been successfully realized. This review will cover the progress of several facilities under construction or being proposed: Spiral2, IFMIF-EVEDA, SPL, ESS, FRIB and ADS drivers.

Slides TUZB01 [10.630 MB]

TUPC008

CLIC Two-Beam Module for the CLIC Conceptual Design and Related Experimental Program

alignment, vacuum, quadrupole, RF-structure

1003

A. Samoshkin, D. Gudkov, A. Solodko
JINR, Dubna, Moscow Region, Russia
G. Riddone
CERN, Geneva, Switzerland

The Compact LInear Collider (CLIC), being studied at CERN, involves the design and integration of many different technical systems, tightly bound and influencing each other. For the construction of two main linacs it has been decided to proceed with a modular design, and repetitive two-beam modules of a few types were defined. The modules consist of micro-precision components operating under ultra-high vacuum as required by the beam physics. For the CLIC Conceptual Design Report, the development and system integration is mainly focused on the most complex module type containing the highest number of components and technical systems. For proving the proper functioning of the needed technical systems and confirming their feasibility it has been decided to build four prototype modules and test them without beam. In addition, three modules have to be produced in parallel for tests in the CLIC Experimental Area with beam. This paper is focused on the design of the different technical systems and integration issues of the two-beam module. The experimental program for the prototype modules is also recalled.

TUPC010

Status of the Manufacturing of Accelerating Structures for LINACs

vacuum, controls, extraction, laser

1009

F.M. Mirapeix, J. Añel, J. Castillo, A. Ortiz
HTS, Mendaro, Spain
X. Aldalur, J. Amores, A. Urzainki
DMP, Mendaro, Spain

Funding: HTS, DMP, ZEHATZ, CERN
Particle accelerators need ongoing development in the state of the art of the field: high-quality manufacturing of accelerating structures, PETS, but also drift tubes, bunchers, high-power couplers, alignment systems, precision test stands, etc. They also require engineering projects in the range of mechatronics, thermodynamics, microwaves, ultra high vacuum, cryogenics, joining techniques, high precision manufacturing, 3D high precision scanning, etc. HTS together with DMP are actually working on all this fronts. In this paper, the actual status of the manufacturing capabilities concerning some accelerating structures will be described.

TUPC012

Fabrication and Validation of the Prototype Supporting System for the CLIC Two-beam Modules

alignment, RF-structure, radiation, tandem-accelerator

1015

N. Gazis, G. Riddone, S. griffet
CERN, Geneva, Switzerland
A. Samoshkin
JINR, Dubna, Moscow Region, Russia

The Compact LInear Collider (CLIC), currently under study at CERN, aims at the development of a Multi-TeV e⁺ e^- collider and relies upon a novel two-beam acceleration concept. In the two-beam acceleration, the Radio Frequency (RF) power is extracted from a low energy but high-intensity particle beam, and it is transferred to a parallel high energy main beam. The two-beam modules are the smallest repetitive units which compose the two linacs. The RF structures are the most precise components and they are mounted and aligned on specially developed supporting system, which provides stability and quick re-positioning. The supporting girders have stringent stiffness and damping requirements, imposed by beam physics requirements. In addition, several constraints, such as allocated space and weight limitation have to be taken into consideration. This paper describes different girder configurations following various fabrication techniques and materials. Extensive qualification measurements have been performed on the first prototype units, and the main results are also presented.

TUPC013

Simulation of Phase Stability at the Flat Top of the CLIC Drive Beam

simulation, luminosity, kicker, collider

1018

A. Gerbershagen, D. Schulte
CERN, Geneva, Switzerland
P. Burrows
Oxford University, Physics Department, Oxford, Oxon, United Kingdom

Funding: University of Oxford
The drive beam phase stability is one of the critical issues of the Compact Linear Collider (CLIC). In this paper the generation and propagation of drive beam phase errors is studied for effects that vary during the drive beam pulse. This includes the influence of drive beam current and phase errors as well as of drive beam accelerator RF phase and amplitude errors on the drive beam phase after the compressor chicanes and the analysis of the propagation of these errors through the drive beam combination scheme. The impact of the imperfections on the main beam is studied including the possible correction with help of a feedforward system.

TUPC017

Civil Engineering Studies for Major Projects after LHC

collider, interaction-region, civil-engineering, site

1030

J.A. Osborne, F.J. Magnin, E. Perez-Duenas
CERN, Geneva, Switzerland

CERN civil engineers are heavily involved in studying several major projects to succeed/complement the LHC. Infrastructure works typically represent one third of the cost of major physics projects, so it's critical that the construction costs are well understood from the conceptual stage. For example, CERN are studying infrastructure requirements for the Linear Collider (CLIC & ILC) and the LHeC projects. This poster presents some of the key civil engineering challenges faced in such large scale projects.

TUPC018

Progress on Modelling of the Thermo-Mechanical Behavior of the CLIC Two-Beam Module

vacuum, RF-structure, simulation, collider

1033

R.J. Raatikainen, K. Osterberg
HIP, University of Helsinki, Finland
T.O. Niinikoski, G. Riddone
CERN, Geneva, Switzerland

The luminosity goal of the CLIC collider, currently under study, imposes micrometer mechanical stability of the 2-m long two-beam modules, the shortest repetitive elements of the main linacs. These modules will be exposed to variable high power dissipation during operation resulting in mechanical distortions in and between module components. The stability of the CLIC module will be tested in laboratory conditions at CERN in a full-scale prototype module. In this paper, the FEA model developed for CLIC prototype module is described. The thermal and structural results for the new module configuration are presented considering the thermo-mechanical behavior of the CLIC collider in its primary operation modes. These results will be compared to the laboratory measurements to be done during 2011 and 2012 with the full-scale prototype module. The experimental results will allow for better understanding of the module behaviour and they will be propagated back to the present thermo-mechanical model.

TUPC020

Alignment and Wake Field Issues in the CLIC RTML

emittance, lattice, wakefield, cavity

1039

F. Stulle, S. Döbert, A. Latina, D. Schulte
CERN, Geneva, Switzerland

At main linac injection the particle beams need to stay within tight tolerances for the transverse emittances and the pointing stability. We study how these tolerances influence alignment requirements for the RTML components and the stability of the beams entering the RTML. An emphasize is put on the booster linac and the RF cavities of the second bunch compression stage since short and long range wake fields might strongly influence beam dynamics in these parts of the RTML.

TUPC021

The CLIC Feasibility Demonstration in CTF3

cavity, acceleration, electron, ion

1042

P.K. Skowroński, J. Barranco, S. Bettoni, B. Constance, R. Corsini, A.E. Dabrowski, M. Divall Csatari, S. Döbert, A. Dubrovskiy, O. Kononenko, M. Olvegård, T. Persson, A. Rabiller, F. Tecker
CERN, Geneva, Switzerland
E. Adli
University of Oslo, Oslo, Norway
W. Farabolini
CEA/DSM/IRFU, France
R.L. Lillestol
NTNU, Trondheim, Norway
T. Muranaka, A. Palaia, R.J.M.Y. Ruber
Uppsala University, Uppsala, Sweden

The objective of the CLIC Test Facility CTF3 is to demonstrate the feasibility issues of the CLIC two-beam technology: the efficient generation of a very high current drive beam, used as the power source to accelerate the main beam to multi-TeV energies with gradient over 100MeV/m, stable drive beam deceleration over long distances. Results on successful beam acceleration with over 100 MeV/m energy gain are shown. Measurements of drive beam deceleration over a chain of Power Extraction Structures are presented. The achieved RF power levels, the stability of the power production and of the deceleration are discussed. Finally, we overview the remaining issues to be shown until the end of 2011.

TUPC022

Design of the CLIC Drive Beam Recombination Complex

emittance, injection, sextupole, synchrotron

1045

J. Barranco, P.K. Skowroński, F. Tecker
CERN, Geneva, Switzerland
C. Biscari
INFN/LNF, Frascati (Roma), Italy

The CLIC Drive Beam Recombination Complex (DBRC) is designed to compress beam pulses from a current of 4.1 A to 100 A before using them to produce RF power in the deceleration lines. The beam is transported isochronously through a complex system consisting of a delay loop, two combiner rings and final turn around. The system is designed to preserve transverse and longitudinal emittances. During the optics design, chromaticity and non-linear dispersion were identified as the main single particle dynamics causes for transverse emittance increase. Different sextupole families are used to compensate these chromatic effects while keeping isochronicity. The bunch length is also adjusted to minimize coherent synchrotron radiation effects on bunch length, energy spread and transverse emittance. Finally, the injection scheme of the combiner rings was improved making the time variable bump created with help of the RF deflectors truly achromatic.

TUPC032

Beam Phase-Space Study for AREAL RF Photogun Linac

gun, emittance, space-charge, electron

1069

B. Grigoryan, G.A. Amatuni, I.N. Margaryan, A.V. Tsakanian, V.M. Tsakanov, A. Vardanyan
CANDLE, Yerevan, Armenia

In order to produce high brightness electron beams with sub-picosecond bunch duration, the creation of Advanced Research Electron Accelerator Laboratory (AREAL) at CANDLE based on photocathode RF gun is under consideration. For several experimental setup purposes the linac will operate in single and multibunch modes with final beam energy 5-20 MeV and the bunch charge 10 100 pC. The study of beam phase space evolution along the linac is performed to optimize the beam main characteristics: emittance, bunch length and energy spread. The dependence of longitudinal and transverse distribution of electrons in photocathode region on RF cavity performances is analyzed.

TUPC033

Verifying the Single Bunch Capability of the New Injector at ELSA*

electron, gun, single-bunch, pick-up

1072

S. Mey, O. Boldt, W. Hillert, N. Hofmann, F. Klarner, D. Krönung, A. Roth, M. Schedler
ELSA, Bonn, Germany
S. Aderhold
DESY, Hamburg, Germany

Funding: Funded by the DFG within the SFB / TR 16 and the Helmholtz Alliance HA 10¹ "Physics at the Terascale".
In order to enhance the operating capabilities of the Bonn University Accelerator Facility, ELSA, a new injector is currently under commissioning. One of its main purpose is to allow a single pulse mode. The injector produces a single electron bunch with 1.5 A pulse current. Design and optimization of the injector have been performed with EGUN, PARMELA and numerical simulations based on the numerical integration of the paraxial equation. A 1 ns long pulse is produced by a thermionic electron source with 90 kV anode - cathode voltage, then compressed and pre-accelerated by a subsequent 500 MHz RF cavity and a four-cell travelling wave buncher. Finally, the bunch will be accelerated to 20 MeV by the main LINAC section. Measurements have been conducted concerning the resulting pulse length and pulse charge to confirm the predictions made by simulations and to investigate the efficiency of the injector system.

TUPC034

Design Studies on 100 MeV/100 kW Electron Linac for NSC KIPT Neutron Source on the Base of Subcritical Assembly Driven by Linac

electron, emittance, gun, target

1075

Y.L. Chi, J. Cao, X.W. Dai, C.D. Deng, M. Hou, X.C. Kong, R.L. Liu, W.B. Liu, C. Ma, G. Pei, H. Song, S.H. Wang, G. Xu, J. Zhao, Z.S. Zhou
IHEP Beijing, Beijing, People's Republic of China
M.I. Ayzatskiy, I.M. Karnaukhov, V.A. Kushnir, V.V. Mytrochenko, A.Y. Zelinsky
NSC/KIPT, Kharkov, Ukraine
S. Pei
IHEP Beijng, Beijing, People's Republic of China

In NSC KIPT, Kharkov, Ukraine, a neutron source on the base of subcritical assembly driven by 100 MeV/100 kW electron linear accelerator is under design and development. To provide neutron flux value of about 1013 neutron/s the electron linear accelerator with 100 MeV beam and average beam power of 100 kW will be used. Construction and manufacture of the linear accelerator of such high beam intensity with low emittance and beam losses is a challenging task. In the report the project of the electron linear accelerator of the required beam energy and intensity is described. The accelerator structure and main technical solutions are presented. To overcome the BBU effect of this high average beam current, several effective measures are adopt, such as using constant gradient structure to spread the HOMs frequencies different cells, larger inner radius and shorter section length make the higher group velocity and optimize the structure geometry to keep the shunt impedance as good as possible. After the beam bunching system, a chicane is followed to chopper the beam to avoid the beam lost in the higher energy part.

TUPC038

A Low Energy Thermionic RF Gun Linac for Ultrashort Electron Beam

gun, electron, bunching, klystron

1081

J.-Y. Hwang, J.H. Chen, W.K. Lau, A.P. Lee, T.H. Wu
NSRRC, Hsinchu, Taiwan
N.Y. Huang
NTHU, Hsinchu, Taiwan

A low energy test linac is being constructed at NSRRC for technological development of high brightness electron injector. It is a 29 MeV S-band linac that equipped with a high gradient thermionic cathode rf gun for generation of ultrashort relativistic electron beam by velocity bunching in the rf linac section located at downstream. High quality GHz-repetition-rate electron pulses of about 30 pC in bunch charge, pulse duration as short as 100 fsec can be produced from this test facility. It can be used as the driver for future light source experiments such as ultrafast head-on inverse Compton scattering (ICS) X-ray source and intense coherent THz free electron lasers.

TUPC042

First Beam to FACET

electron, positron, controls, vacuum

1093

R.A. Erickson, C.I. Clarke, W.S. Colocho, F.-J. Decker, M.J. Hogan, S. Kalsi, N. Lipkowitz, J. Nelson, N. Phinney, P. Schuh, J. Sheppard, H. Smith, T.J. Smith, M. Stanek, J.L. Turner, J. Warren, S.P. Weathersby, U. Wienands, W. Wittmer, M. Woodley, G. Yocky
SLAC, Menlo Park, California, USA

Funding: This work was supported by the Department of Energy contract DE-AC02-76SF00515.
The SLAC 3km linear electron accelerator has been reconfigured to provide a beam of electrons to the new FACET facility while simultaneously providing an electron beam to the Linac Coherent Light Source (LCLS). FACET is a new experimental facility constructed in the linac tunnel that can transport, compress, and focus electron bunches to support a variety of accelerator R&D experiments. In this paper, we describe our first experiences with the operation of the linac for this new facility.

TUPC045

Recirculating Electron Linacs (REL) for LHeC and eRHIC

electron, lattice, dipole, proton

1099

D. Trbojevic, J. Beebe-Wang, Y. Hao, D. Kayran, V. Litvinenko, V. Ptitsyn, N. Tsoupas
BNL, Upton, Long Island, New York, USA

Funding: Work performed under a Contract Number DE-AC02-98CH10886 with the auspices of the US Department of Energy.
We present a design of a CW Electron Recovery Linacs (ERL) for future electron hadron colliders eRHIC and LHeC. In eRHIC, a six-pass ERL would be installed in the existing tunnel of the present Relativistic Heavy Ion Collider (RHIC). The 5-30 GeV polarized electrons will collide with RHIC’s 50-250 (325) GeV polarized protons or 20-100 (130) GeV/u heavy ions. In LHeC a 3-pass 60 GeV CW ERL will produce polarized electrons for collisions with 7 TeV protons. After collision, electron beam energy is recovered and electrons are dumped at low energy. Two superconducting linacs are located in the two straight sections in both ERLs. The multiple arcs are made of Flexible Momentum Compaction lattice (FMC) allowing adjustable momentum compaction for electrons with different energies. The multiple arcs, placed above each other, are matched to the two linac’s straight sections with splitters and combiners.

TUPC054

LHeC ERL Design and Beam-dynamics Issues

optics, emittance, HOM, cavity

1120

S.A. Bogacz, I. Shin
JLAB, Newport News, Virginia, USA
D. Schulte, F. Zimmermann
CERN, Geneva, Switzerland

We discuss machine and beam parameter choices for a Linac-Ring option of the Large Hadron electron Collider (LHeC) based on the LHC. With the total wall-plug power limited to 100 MW and a target current of about 6 mA the desired luminosity of 10³3 cm^-2 s^-1 can be reached, providing one exploits unique features of the Energy Recovery Linac (ERL). Here, we describe the overall layout of such ERL complex located on the LHC site. We present an optimized multi-pass linac optics enabling operation of the proposed 3-pass Recirculating Linear Accelerator (RLA) in the Energy Recovery mode. We also describe emittance preserving return arc optics architecture; including layout and optics of the arc switch-yard. Furthermore, we discuss importance of collective effects such as: beam breakup in the RLA, as well as ion accumulation, with design-integrated mitigation measures, and the electron-beam disruption in collision. Finally, a few open questions are highlighted.

TUPC066

Charged Particle Beam Profile Detector based on Yb-doped Optical Fibers

radiation, proton, ion, laser

1150

C.S. Søndergaard
Aarhus University Hospital, Aarhus, Denmark
A. Baurichter, B.R. Nielsen
Danfysik A/S, Jyllinge, Denmark
G. Boudreault
Rigshospitalet Copenhagen, PET and Cyclotron Unit, Copenhagen, Denmark
K. Hansen, D.V. Madsen, J. Rasmussen, B.F. Skipper
Aarhus School of Engineering, Aarhus, Denmark
M. Kristensen
Aarhus University, Aarhus, Denmark
S.P. Møller
ISA, Aarhus, Denmark
A. Peters
HIT, Heidelberg, Germany

Funding: The Danish National Advanced Technology Foundation, contract # 002-2005-1
A radiation robust, high dynamic range beam profile detector based on scintillating fibers will be presented. The beam profile detector has been developed for particle therapy type ion beams of multiple hundreds MeV/n in the intensity range from 10⁵ to 10⁹ ions/s as a simple and less expensive replacement for MWPC based detectors. Scintillating fibers are typically based on doped polymers, which are sensitive to radiation damage. Here we report on the advantage of using silica optical fibers doped with rare-earth elements for the purpose of detecting ionizing radiation. Specifically, we find that ytterbium doped fibers generate a strong emission signal in the near-infrared from the Yb³⁺ state when penetrated by ionizing radiation, and that the emission has a high resistance against the accumulated dose in the fiber. We demonstrate the use of such fibers in a beam profile detector for charged particle beams in medical applications (radionuclide production and hadron therapy); more generally they are a promising alternative for prolonged used in ionizing radiation, such as accelerator diagnostics equipment or space applications.

TUPC070

SAFARI, an Optimized Beam Stop Device for High Intensity Beams at the SPIRAL2 Facility

beam-transport, neutron, beam-losses, vacuum

1162

E. Schibler
IN2P3 IPNL, Villeurbanne, France
L. Perrot
IPN, Orsay, France

The SPIRAL2 facility at GANIL-Caen is now in its construction phase, with a project group including the participation of many French laboratories (CNRS, CEA) and international partners. The facility will be able to produce various accelerated beams at high intensities: 40 MeV Deuterons, 33 MeV Protons with intensity until 5mA and heavy ions with A/Q=3 up to 14.5MeV/u until 1mA current. We will present the final status of the 200kW beam stop located in the high energy beam transport lines. From the beam characteristics (HEBT line up to beam stop) and activation constraints, we studied and developed a complete design of a new high efficiency Beam Stop that has been nicknamed SAFARI (Système Arrêt Faisceau Adapté Rayons Intenses - Optimized Beam Stop Device for High Intensity Beams). Special focus will be done on the adequacy between beam dynamic and thermo-mechanical behavior. The Beam Stop shape marries to the beam characteristics in order to smooth for the best power density and improve thermo-mechanical behavior under nominal and critical beams. Optimization by various fluids studies and calculations led us to a new high efficiency counter-current water cooling system.

TUPC097

Status of Cold Cavity Beam Position Monitor for STF

cavity, cryomodule, vacuum, coupling

1236

E.-S. Kim, A. Heo
KNU, Deagu, Republic of Korea
H. Hayano
KEK, Ibaraki, Japan

Cold cavity BPM was developed to meet high position resolution and bunch to bunch measurement time. It is designed based on re-entrant cavity and has Low-Q to achieve short signal decay time in L-band frequency with large aperture as 78mm. The beam test was performed to demonstrate position resolution at ATF main linac, which is operating with 1.6nC bunch charge, while BPM will be installed inside the ILC cyomodule with 3.2nC spacing 369ns like as ILC at STF. Stripline BPMs, ML2P and ML3P installed upstream and downstream of the BPM’s location respectively were used to predict its position. Reference cavity was optimized to use for synchronous detection. We had achieved ~340nm position resolution since position resolution was estimated due to limitation of system with noise, namely in case of ideal state. We will present configuration of beam test, procedure to measure position resolution and the result on the test. Furthermore, new design will be introduced to improve signal intensity and have heavy coupling.

TUPC099

New Measurements of Proton Beam Extinction at J-PARC

proton, injection, secondary-beams, vacuum

1242

K. Yoshimura, Y. Hori, Y. Igarashi, S. Mihara, H. Nishiguchi, Y. Sato, M. Shimamoto, Y. Takeda, M. Uota
KEK, Ibaraki, Japan
M. Aoki, S. Hikida, H. Nakai
Osaka University, Osaka, Japan
Y. Hashimoto
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

Proton beam extinction, defined as a residual to primary ratio of beam intensity, is one of the most important parameters to realize the future muon electron conversion experiment (COMET) proposed at J-PARC. To achieve the required extinction level of 10^-9, we started measuring extinction at main ring (MR) as its first step. According to the various measurements done at the different positions, empty RF buckets of RCS, which were considered to be swept away by the RF chopper, contained about 10^-7 ~ 10^-5 of the main beam pulse due to chopper inefficiency. We have developed a new beam monitor with improved performance for further studies at the abort line. In addition, we have started new measurements at the Hadron experimental hall by using slow-extracted beam. In this paper, we present recent results and future prospect of beam extinction measurements.

TUPC100

Longitudinal Beam Profile Measurement at J-PARC Separated Drift Tube Linac

beam-losses, cavity, simulation, injection

1245

T. Maruta
KEK/JAEA, Ibaraki-Ken, Japan
M. Ikegami
KEK, Ibaraki, Japan
A. Miura, G.H. Wei
JAEA/J-PARC, Tokai-mura, Japan
H. Sako
JAEA, Ibaraki-ken, Japan

We measured longitudinal beam profile at Separated Drift Tube Linac (SDTL) injection part by scanning beam transmission and beamloss at the downstream of SDTL section by changing SDTL injection phase. As the beam goes to acceptance edge, part of the beam which is out of acceptance isn't accelerate and finally it is lost by hitting to beam duct. Thus beam transmission shows sliced bunch shape by acceptance edge, it is possible to reconstruct the beam bunch shape. The result shows about 60% wider profile in both phi and E direction against to design.

TUPC101

Generation of Multimode Quasi-monochromatic Terahertz

electron, radiation, gun, cathode

1248

K. Kan, T. Kondoh, K. Norizawa, A. Ogata, J. Yang, Y. Yoshida
ISIR, Osaka, Japan

Generation of quasi-monochromatic terahertz (THz) using multimode Coherent Cherenkov Radiation (CCR) on the order of 0.1 THz was investigated. CCR was generated by a hollow dielectric tube covered by a metal and an electron bunch from a photocathode radio-frequency (RF) gun linac. The intensity and frequency of CCR were measured directly by a Michelson interferometer and a bolometer. The frequency spectra measured by the interferometer indicated sharp peaks close to frequencies of 0.09 THz and 0.14 THz, which corresponded to TM03 and TM04 modes, respectively, according to theoretical calculation for a tube with inner and outer radii of 5 mm and 7 mm. The maximum gain of TM03 mode due to the tube length was obtained as 1.5 dB/cm. The other higher modes, e. g. 0.36 THz (TM09) and 0.40 THz (TM010), were also observed from a 150 mm long tube at a bunch charge of 15 pC, which decreased space charge effect and the bunch length. Finally, a new method for bunch diagnostic based on multimode CCR was proposed. The bunch length was estimated to be 0.45 ps at a bunch charge of 5 pC with the intensity ratio of TM03 to TM09 mode.

TUPC102

Measurement of Beam Loss Tracks by Scintillating Fibers at J-PARC Linac

beam-losses, background, simulation, gun

1251

H. Sako, T. Maruta, A. Miura
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

Highest beam loss in the J-PARC linac has been observed that the ACS (Annular-Coupled Structure linac) section. Since the observed beam loss is proportional to the residual gas pressure, the source of the beam loss is considered as H0 produced in an interaction of H⁻ beams with remnant gas. If this assumption is valid, H0 hits the beam duct and changes into H⁺ and escapes from the beam duct. We constructed scintillation fiber hodoscopes to detect H⁺s and eventually identify the particle species as H⁺. The hodoscopes are made of 4 planes of hodoscopes which consists of 16 scintillation fibers of 64mm long and with 4mmx4mm cross section. We installed the hodoscopes at the upstream part of the ACS section and measured beam loss. The results are shown in this paper.

TUPC104

Beam Loss Detected by Scintillation Monitor

beam-losses, cavity, simulation, hadron

1257

A. Miura, K. Hasegawa, T. Maruta, N. Ouchi, H. Sako
JAEA/J-PARC, Tokai-mura, Japan
Z. Igarashi, M. Ikegami, T. Miyao
KEK, Ibaraki, Japan

Ar gas proportional BLMs have measured the beam loss through operations, but they are also sensitive to background noise of X-ray emitted from RF cavities. We have tried to measure the beam loss using scintillation monitors which would bring more accurate beam loss measurements with suppression of X-ray noise. We measured beam loss using scintillation beam loss monitors. Because this scintillation BLM is sensitive for low energy gamma-rays and fast neutrons, small signals from X-rays would be also detected. As the measurement results, a good signal to noise ratio is observed for the scintillation monitor with quite low sensitivity to the background X-ray. And many single events are observed in the intermediate pulse bunch with about 600 ns as pulse width. In addition, because we fabricated the filter and integrated circuit, total amount of X-ray noise can become smaller. We obtained the good performances of scintillation BLM with small effect of X-ray noise. This monitor can be used for beam loss measurement and a knob for tuning. Furthermore, because the detail structure can be detected, this monitor could be employed for another diagnostic device.

TUPC105

Improvement of Beam Current Monitor with High Tc Current Sensor and SQUID at the RIBF

ion, cyclotron, heavy-ion, ECR

1260

T. Watanabe, N. Fukunishi, O. Kamigaito, M. Kase, Y. Sasaki
RIKEN Nishina Center, Wako, Japan

A highly sensitive beam current (position) monitor with a high Tc (Critical Temperature) current sensor and a SQUID (Superconducting QUantum Interference Device), that is the HTc-SQUID monitor, has been developed for the RIBF (RI Beam Factory) in RIKEN. The purpose of our work is to measure the DC of high-energy heavy-ion beams nondestructively in such a way that the beams are diagnosed in real time and the beam current extracted from the cyclotron can be recorded without interrupting the beam user's experiments. Both the HTc magnetic shield and the HTc current sensor were dip-coated by thin layer of Bi-Sr-Ca-Cu-O (2223-phase, Tc=10⁶ K) on 99.9 % MgO ceramic substrates. Unlike other existing facilities, all these HTS fabrications are cooled by a low-vibration pulse-tube refrigerator. These technologies enable us to downsize the system. As a result, 1 uA Xe beam intensity (50 MeV/u) was successfully measured with a 10⁰ nA resolution. From last year, aiming at the higher resolution, improvement of the new HTc current sensor with two turn coils has been started. We will report the present status and the measurement results of the HTc-SQUID monitor.

TUPC115

Application of Libera Brilliance Single Pass at NSRL Linac BPM System

brilliance, controls, pick-up, injection

1284

J.Y. Zou, J. Fang, P. Lu, T.J. Ma, B.G. Sun, Y.L. Yang, Z.R. Zhou
USTC/NSRL, Hefei, Anhui, People's Republic of China

Libera Brilliance Single Pass is a digital beam position processor with capabilities of single pass position measurement. This device can be used on the stripline beam position monitor (BPM) of the linac and transfer lines on light sources as well as injector system for the FELs. The linac of Hefei light source (HLS) was equipped with 2 stripline beam position monitors, which will be increased to 20 BPMs after upgrading. The existing BPM electronics were the homemade electronics with logarithm detector. To enhance the functionality of the BPM system, the Libera Brilliance Single Pass is employed to replace the existing BPM electronics. The newly buying devices have made test of characterization. The mapping of stripline BPM is made on a workbench with Libera Brilliance Single Pass. The beam position is tested at linac using Libera Brilliance Single Pass. And the results of these measurement performed on Libera are reported to compared to measurements with the linac’s existing BPM electronics.

TUPC125

Test of the Front-end Electronics and Acquisition System for the LIPAC BPMs

EPICS, pick-up, controls, LLRF

1311

D. Belver, I. Arredondo, P. Echevarria, J. Feuchtwanger, H. Hassanzadegan, M. del Campo
ESS-Bilbao, Zamudio, Spain
F.J. Bermejo
Bilbao, Faculty of Science and Technology, Bilbao, Spain
J.M. Carmona, A. Guirao, A. Ibarra, L.M. Martinez Fresno, I. Podadera
CIEMAT, Madrid, Spain
V. Etxebarria, J. Jugo, J. Portilla
University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain
N. Garmendia, L. Muguira
ESS Bilbao, Bilbao, Spain

Funding: Work partially supported by Spanish Ministry of Science and Innovation under project AIC10-A-000441 and ENE2009-11230.
Non-interceptive Beam Position Monitors pickups (BPMs) will be installed along the beamlines of the IFMIF/EVEDA linear prototype accelerator (LIPAC) to measure the transverse beam position in the vacuum chamber in order to correct the dipolar and tilt errors. Depending on the location, the BPMs response must be optimized for a beam of 175 MHz bunch repetition, an energy range from 5 up to 9 MeV, a current between 0.1 and 125 mA and continuous and pulse operation. The requirements from beam dynamics for the BPMs are quite stringent, aiming for the position an accuracy below 100 μm and a resolution below 10 μm, and for the phase an accuracy below 2° and a resolution below 0.3°. To meet these specifications, the BPM electronics system developed by ESS-Bilbao has been adapted for its use with the BPMs of LIPAC. This electronics system is divided in an Analog Front-End unit, where the signals are conditioned and converted to baseband, and a Digital Unit to sample them and calculate the position and phase. The electronics system has been tested at CIEMAT with a wire test bench and a prototype BPM. In this contribution, the tests performed will be fully described and the results discussed.

TUPC130

Beam Test Performance of the Beam Position Monitors for the TBL Line of the CTF3 at CERN

pick-up, quadrupole, monitoring, beam-transport

1326

J.J. García-Garrigós, C. Blanch Gutierrez, J.V. Civera, A. Faus-Golfe
IFIC, Valencia, Spain
S. Döbert
CERN, Geneva, Switzerland

Funding: Funding Agency: FPA2010-21456-C02-01
A series of Inductive Pick-Ups (IPU) for Beam Position Monitoring (BPM) with its associated electronics were designed, constructed and tested at IFIC. A full set of 16 BPMs, so called BPS units, were successfully installed in the Test Beam Line (TBL) of the CLIC Test Facility (CTF3) at CERN. In this paper we present the results of the beam test carried out on the BPS units of the TBL in order to determine their beam performances and check the specified operational requirements. We focus particularly on the position resolution parameter which is the BPS figure of merit according to TBL demands and is expected to reach the 5um resolution at maximum beam current (28A). The beam test results of the BPS units are also compared with the parameters from their previous characterization test at lab.

TUPC134

Phase Detection Electronics for CLIC

pick-up, controls, luminosity, linear-collider

1338

A. Andersson
CERN, Geneva, Switzerland

The Compact Linear Collider (CLIC) requires very tight RF phase synchronisation in order to preserve high luminosity. The electronics required for processing the signals delivered from the phase pick-ups present a significant challenge. This paper discusses the strategy adopted to achieve a sufficiently accurate measurement of the phase. Performance measurements performed in the lab of some of the sub-systems are also presented.

TUPC139

Overview of the CLIC Beam Instrumentation

cavity, beam-losses, laser, instrumentation

1350

T. Lefèvre
CERN, Geneva, Switzerland

Driven by beam dynamic considerations the Compact Linear Collider (CLIC) is expected to require extremely tight tolerances on most beam parameters. An important milestone was reached in 2011 with the completion of the CLIC conceptual design report. In this context the requirements for CLIC beam instrumentation has been reviewed and studied in detail for the whole accelerator complex with the aim of demonstrating feasibility. A preliminary choice has been made for every CLIC instrument, serving as a baseline scenario for the next phase of the project which will concentrate on the detailed design, engineering and test of CLIC devices. Whenever possible existing solutions have been studied, focusing on any improvements necessary to meet the CLIC performance criteria. When no such devices exists, or if cost considerations come into play, new technologies have been under study. Several prototypes are already well advanced and are currently under test. This paper presents an overview of CLIC beam instrumentation, the possible reach of their performance and an outlook on future developments.

TUPC165

DITANET - Investigations into Accelerator Beam Diagnostics

diagnostics, electron, instrumentation, extraction

1422

C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

Funding: Work supported by the EU under GA-PITN-215080.
DITANET is a Marie Curie initial training network in beam diagnostics. The network members, universities, research centres and industry partners, are developing diagnostics methods for a wide range of existing or future particle accelerators, both for electron and for ion beams. This is achieved through a cohesive approach that allows for the exploitation of synergies, whilst promoting knowledge exchange between partners. In addition to its broad research program, the network organizes schools and topical workshops for the beam instrumentation and particle accelerator communities. This contribution gives an overview of the Network's research outcomes to date and summarizes past and future training activities.

TUPC171

2D Optical Streaking for Ultra-short Electron Beam Diagnostics

laser, electron, simulation, diagnostics

1437

L. Wang, Y.T. Ding, Z. Huang
SLAC, Menlo Park, California, USA

We propose a novel approach to measure the short electron bunch profile at micrometer level. Low energy electrons generated during beam-gas ionization are simultaneously modulated by the transverse electric field of a circularly-polarized laser, and then they are collected at a down-stream screen where the angular modulation are converted to a circular shape there. The longitudinal bunch profile is simply represented by the angular distribution of the electrons on the screen. We only need to know the laser wavelength for calibration and there is no phase synchronization problem. Meanwhile the required laser power is also relatively low in this setup. Some simulations examples and resolution of this method will be discussed.

TUPO007

FLUTE, a Linac Based THz Source

radiation, gun, synchrotron, synchrotron-radiation

1458

S. Naknaimueang, M. Schwarz
Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
R. Abela, H.-H. Braun, R. Ganter, B. Patterson
PSI, Villigen, Switzerland
A.H. Albert, T. Baumbach, M. Hagelstein, N. Hiller, E. Huttel, V. Judin, B. Kehrer, R. Kubat, S. Marsching, W. Mexner, A.-S. Müller, M.J. Nasse, A. Plech, R. Rossmanith, M. Schuh
KIT, Karlsruhe, Germany
M.T. Schmelling
MPI-K, Heidelberg, Germany

We propose a versatile THz source named FLUTE (“Ferninfrarot Linac- Und Test-Experiment”) based on a 30 - 50 MeV S-band linac with bunch compressor, that shall not only provide high field THz pulses applications but shall also serve as a test facility to study important accelerator physics issues. This is also of importance in view of the planned utltra-broadband THz to mid infrared user facility TBONE. Special emphasis is put on studies of bunch compression and beam stability as a function of bunch charge (0.1-5 nC) and of different generation mechanisms of coherent radiation (CSR, CER, CTR). This paper describes the design and layout of the proposed FLUTE machine and presents results of beam dynamic calculations with the tracking programs ASTRA and CSRtrack.

TUPO008

Electron Linac Optimization for Driving Bright Gamma-ray Sources based on Compton Back-scattering

electron, photon, laser, emittance

1461

L. Serafini, F. Broggi, C. De Martinis, D. Giove
Istituto Nazionale di Fisica Nucleare, Milano, Italy
D. Alesini, P. Antici, A. Bacci, M. Bellaveglia, R. Boni, E. Chiadroni, G. Di Pirro, A. Esposito, M. Ferrario, A. Gallo, G. Gatti, A. Ghigo, E. Pace, A.R. Rossi, B. Spataro, P. Tomassini, C. Vaccarezza
INFN/LNF, Frascati (Roma), Italy
A. Cianchi
Università di Roma II Tor Vergata, Roma, Italy
C. Maroli, V. Petrillo
Universita' degli Studi di Milano, Milano, Italy
M. Migliorati, A. Mostacci, L. Palumbo
Rome University La Sapienza, Roma, Italy

We study the optimal lay-out and RF frequency for a room temperature GeV-class Electron Linac aiming at producing electron beams that enhance gamma-ray sources based on Compton back-scattering. These emerging novel sources, generating tunable, mono-chromatic, bright photon beams in the range of 5-20 MeV for nuclear physics as well as nuclear engineering, rely on both, high quality electron beams and J-class high repetition-rate synchronized laser systems in order to achieve the maximum spectral density of the gamma-ray beam (# photons/sec/eV). The best option among the conventionally used RF linac-bands (S, C, X) and possible hybrid schemes will be analyzed and discussed, focusing the study in terms of best performances for the gamma-ray source, its reliability and compactness. We show that the best possible candidates for a Gamma-ray driver are quite similar to those of FEL Linacs.

TUPO021

Dielectric Wakefield Accelerator to Drive the Future FEL Light Source

wakefield, FEL, electron, acceleration

1485

C.-J. Jing, A. Kanareykin
Euclid TechLabs, LLC, Solon, Ohio, USA
J.G. Power, A. Zholents
ANL, Argonne, USA

X-ray free-electron lasers (FELs) are expensive instruments and a large part of the cost of the entire facility is driven by the accelerator. Using a high-energy gain dielectric wake-field accelerator (DWA) instead of the conventional accelerator may provide a significant cost saving and reduction of the facility size. In this article, we investigate using a collinear dielectric wakefield accelerator to provide a high repetition rate, high current, high energy beam to drive a future FEL x-ray light source. As an initial case study, a ~100 MV/m loaded gradient, 850 GHz quartz dielectric based 2-stage, wakefield accelerator is proposed to generate a main electron beam of 8 GeV, 50 pC/bunch, ~1.2 kA of peak current, 1MHz (10 beamlines) in just 100 meters with the fill factor and beam loading considered.

TUPO028

Emittance Compensation Scheme for the BERLinPro Injector

emittance, space-charge, solenoid, booster

1497

A.V. Bondarenko, A.N. Matveenko
HZB, Berlin, Germany

Following funding approval late 2010, Helmholtz-Zentrum Berlin officially started Jan. 2011 the design and construction of the Berlin Energy Recovery Linac Project BERLinPro. The initial goal of this compact ERL is to develop the ERL accelerator physics and technology required to accelerate a high-current (100 mA) low emittance beam (1 mm•mrad normalized), as required for future ERL-based synchrotron light sources. Given the flexibility ERLs provides, a short bunch operation mode will also be investigated. The space charge is the main reason of emittance degradation in injector due to rather low injection energy (7 MeV). The implementation of emittance compensation scheme in the injector is necessary to achieve such low emittance. Since injector’s optics is axially non-symmetric, the 2D- emittance compensation scheme* is proposed to be used. Other sources of emittance growth are also discussed.
* S.V. Miginsky, "Emittance compensation of elliptical beam", NIM A 603 (2009) 32.

TUPO029

Status of the BERLinPro Optics Design

emittance, vacuum, optics, electron

1500

A.N. Matveenko, M. Abo-Bakr, A.V. Bondarenko, A. Jankowiak, J. Knobloch, B.C. Kuske, Y. Petenev
HZB, Berlin, Germany

Following funding approval late 2010, Helmholtz-Zentrum Berlin officially started Jan. 2011 the design and construction of the Berlin Energy Recovery Linac Project BERLinPro. The initial goal of this compact ERL is to develop the ERL accelerator physics and technology required to accelerate a high-current (100 mA) low emittance beam (1 mm•mrad normalized), as required for future ERL-based synchrotron light sources. Given the flexibility ERLs provides, a short bunch operation mode will also be investigated. Current optics was designed to allow of low emittance and short bunch operation modes. Optics is flexible to suppress BBU and minimize CSR effects. Estimation of impact of ion accumulation, wake fields, halo and chromatic aberrations is given. Requirements for beam diagnostic system, alignment accuracy and power supply stability are investigated.

TUPO031

The Shielding Design of BERLinPro

neutron, electron, shielding, radiation

1503

K. Ott, M. Helmecke
HZB, Berlin, Germany

Funding: Funded by the Bundesministerium für Bildung und Forschung and by the Land Berlin.
The Helmholtz-Zentrum Berlin started in January 2011 the design and construction of the Berlin Energy Recovery Linac Project BERLinPro as a demonstrator of ERL science and technology. BERLinPro consists of a SRF photo injector, a merger, superconducting booster and linac modules, the ring and a beamdump. The energy is 50 MeV, the maximum current is 100 mA (cw), acceleration to higher energies is an option for the future. The low energy parts of the machine are operated at about 10 MeV. Due to the potential radiation hazard posed by the tremendous beampower the facility will be placed subterraneously. The shielding concept is presented here. We used the Monte Carlo code FLUKA to calculate the details of the shielding, activations, energy doses for radiation damage and energy spectra for realistic scenarios. Due to computing time reasons we used FLUKA calculations in the 50 MeV to 1 GeV range to derive analytical formulas for the vertical shielding. Extrapolation of existing formulas valid in the GeV range (or below 100 MeV) are not applicable because of the rapidly increasing cross section of photo pion production between 100 and 200 MeV.

TUPO034

Longitudinal Stability of ERL with Two Accelerating RF Structures

cavity, electron, RF-structure, simulation

1509

Ya.V. Getmanov, O.A. Shevchenko
BINP SB RAS, Novosibirsk, Russia
N. Vinokurov
NSU, Novosibirsk, Russia

Modern ERL projects use superconductive accelerating RF structures. Their RF quality is typically very high. Therefore, the RF voltage induced by electron beam is also high. In ERL the RF voltage induced by the accelerating beam is almost canceled by the RF voltage induced by the decelerating beam. But, a small variation of the RF voltage may cause the deviations of the accelerating phases. These deviations then may cause further voltage variation. Thus the system may be unstable. The stability conditions for ERL with one accelerating structure are well known [*, **]. The ERL with split RF structure was discussed recently [***, ****]. The stability conditions for such ERLs are discussed in this paper.
* L. Merminga et al.,Annu. Rev.Nucl. Part. Sci. 53 (2003) 387.
** N.A. Vinokurov et al.,Proc. SPIE 2988 (1997) 221.
*** D. Douglas, ICFA BD-Nl 26 (2001) 40.
****N.A. Vinokurov et al.,Proc. IPAC’10.

TUPO035

Beam Dynamics at the ALICE Accelerator R&D Facility

FEL, simulation, booster, cavity

1512

F. Jackson
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Funding: Science and Technology Facilities Council
ALICE is an energy recovery accelerator which drives an infrared free electron laser (IR FEL), based at STFC Daresbury Laboratory. Beam dynamics are of primary importance for the operation of the IR FEL, to ensure sufficient peak current with minimal energy spread and transverse emittance. Measurements of beam parameters are presented and compared with particle tracking simulations. Of particular interest in the ALICE machine is the relatively long injection line where space charge and velocity bunching effects can be significant.

TUPS014

Vacuum Performance Simulation of C-band Accelerating Structures

vacuum, cavity, simulation, free-electron-laser

1548

H. Lee, M.-H. Cho, S.H. Kim, C.H. Yi
POSTECH, Pohang, Kyungbuk, Republic of Korea
W. Namkung, C.D. Park
PAL, Pohang, Kyungbuk, Republic of Korea

Funding: This work is partly supported by the MEST and POSTECH Physics BK21 program.
A C-band accelerating structure has a higher accelerating gradient than that of the S-band structure. It provides a good advantage of a shorter machine length. In order to effectively use RF power and for cost reduction, the accelerating structure should be as long as possible. We propose a 2.2-m long structure compared to 1.8-m at SACLA (SPring-8 Angstrom Compact free electron LAser). However, a longer accelerating structure has worse vacuum performance than a shorter accelerating structure. Thus, the vacuum conductance of 2.2-m long structure has to be checked. We calculate vacuum performance of the accelerating structure by 1-D analytical method and 3-D finite element method (FEM). It is shown that the vacuum performance for the 2.2-m long accelerating structure is safe enough for the XFEL LINAC.

TUPS038

Design of a Beam Dump for 3 to 100 MeV for the New H⁻ Beam in the CERN Linac4

vacuum, proton, radiation, ion

1620

C. Maglioni
CERN, Geneva, Switzerland

In this paper the design of a beam dump for the energy range from 3 to 100 MeV is reported. The dump is developed as temporary dump for the commissioning phase of the Linac4 Project, under construction at CERN, and will be installed in different periods to withstand a beam of different intensities and energies, following the chronological assembly of the linac. The dump design and its functionalities, as well as material choice, criticalities and cooling system are described. Finally, the results from the numerical and analytical thermo-mechanical analyses are reported, while the use of the dump also at 160 MeV is investigated.

TUPS041

Thermo-mechanical Study of a CLIC Bunch Train hitting a Beryllium Energy Spoiler Model

radiation, collimation, wakefield, simulation

1629

J.-L. Fernández-Hernando, D. Angal-Kalinin
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
J. Resta-López
IFIC, Valencia, Spain

A thermo-mechanical study of the impact a CLIC bunch train has over a beryllium energy spoiler has been made. Beryllium has a high electrical and thermal conductivity which together with a large radiation length compared to other metals makes it an optimal candidate for a long tapered design spoiler that will not generate high wakefields, which might degrade the orbit stability and affect the collider luminosity. This paper shows the progress made from the paper presented last year in IPAC 2010. While in the aforementioned paper the study of the temperature and stress was made for the duration of the bunch train this time the study shows the evolution of the stress in the spoiler body 3 microseconds after the bunch train hit.

TUPS057

Displacement of J-PARC Caused by Megaquake

extraction, alignment, hadron, survey

1662

M.J. Shirakata, Y. Fujii, T. Ishii, Y. Shirakabe
KEK, Ibaraki, Japan
H. Harada, S. Harjo, T. Iwahashi, S.I. Meigo, T. Morishita, N. Tani
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

Accelerators, beam lines, and experimental halls located in the J-PARC site were displaced by the 2011 off the Pacific coast of Tohoku Earthquake happened on 11th March, whose magnitude was nine, and its following many aftershocks. Site-wide network of measurement points distributed on grounds, buildings, and magnets was surveyed by using GPS survey system, precise digital levels, and laser trackers. The effect from the megaquake was reported for each J-PARC components, such as LINAC, Rapid Cycling Synchrotron (RCS), Main Ring (MR), neutrino and hadron beam lines, and experimental halls.

TUPS096

ESS Parameter List Database and Web Interface Tools

lattice, neutron, cavity, HOM

1762

K. Rathsman, S. Peggs, P. Reinerfelt, G. Trahern
ESS, Lund, Sweden
J. Bobnar
Cosylab, Ljubljana, Slovenia

The European Spallation Source is an intergovernmental project building a multidisciplinary research laboratory based upon the world's most powerful neutron source. The main facility will be built in Lund, Sweden. Construction is expected to start around 2013 and the first neutrons will be produced in 2019. The ESS linac delivers 5 MW of power to the target at 2.5 GeV, with a nominal current of 50 mA. The Accelerator Design Update (ADU) collaboration of mainly European institutions will deliver a Technical Design Report at the end of 2012. To ensure consistency of the information being used amongst all subgroups throughout the period of accelerator design and construction, a parameter list database and web interface have been proposed. The main objective is to provide tools to identify inconsistencies among parameters and to enforce groups as well as individuals to work towards the same solution. Another goal is to make the Parameter Lists a live and credible endeavor so that the data and supporting information shall be useful to a wider audience such as external reviewers as well as being easily accessible.

TUPS100

Manufacturing the Linac4 PI-mode Structure Prototype at CERN

cavity, vacuum, alignment, controls

1774

G. Favre, A. Cherif, A. Dallocchio, J.-M. Geisser, L. Gentini, F. Gerigk, S.J. Mathot, M. Polini, S. Sgobba, T. Tardy, R. Wegner
CERN, Geneva, Switzerland

The PI-Mode Structure (PIMS) of Linac4 consists of 7-cell cavities made from alternating OFE copper discs and rings welded together with electron beam (EB) welding. A full-scale prototype cavity of almost 1.5 m in length has been manufactured, assembled, and tested at CERN to prepare the series production of 12 PIMS cavities as part of an international collaboration. This paper reports on the construction experience including machining operations, EB welding, vacuum brazing, and metrological measurements results.

TUPS101

A Fast 650V Chopper Driver

controls, impedance, status, kicker

1777

M.M. Paoluzzi
CERN, Geneva, Switzerland

In the framework of Linac4 and the Superconducting Proton Linac (SPL) studies at CERN, the design for a beam chopper has been carried out. The chopper is basically a kicker that deviates part of the beam towards a dump. It is made of two 50 Ω, slow wave lines facing each other, matching the beam velocity and driven with a minimum of 500 V. Due to the bunch spacing of 2.84 ns, a system rise and fall time (3 %-90 %) below 2.5 ns is required with pulse lengths ranging from 8 ns to hundreds of μs. Although different solutions for the driver amplifier where devised in the past, none of the achievements was entirely satisfactory. This paper describes a new design and prototype that meets all the required specifications.

TUPZ041

Site Studies for the SuperB Collider and Synchrotron Radiation Facility Project

site, ground-motion, collider, injection

1900

S. Tomassini, M.E. Biagini, P. Raimondi, C. Sanelli
INFN/LNF, Frascati (Roma), Italy
B. Bolzon
CERN, Geneva, Switzerland
G. Deleglise, A. Jeremie
IN2P3-LAPP, Annecy-le-Vieux, France
J.T. Seeman
SLAC, Menlo Park, California, USA

The SuperB project aims at the construction of a very high luminosity (10³⁶ cm^-2 s⁻¹) asymmetric electron-positron collider. Due to its large beam current (~2 A) high energy (~7 GeV) and low vertical emittance (less than 10^-11 m) the facility looks very attractive as an x-ray synchrotron radiation source, and therefore few beam lines are also foreseen. Possible locations are the campus of the University of Rome Tor Vergata or near another Italian INFN laboratory site. This paper presents and describes the status of the preliminary design of the civil infrastructure layout and related site issues.

WEOAA03

Approach to a Start-to-end Simulation of 2-loop Compact Energy Recovery Linac

electron, simulation, emittance, optics

1909

M. Shimada, K. Harada, Y. Kobayashi, T. Miyajima, N. Nakamura, S. Sakanaka
KEK, Ibaraki, Japan
R. Hajima
JAEA, Ibaraki-ken, Japan

Transport of an extreme low emittance electron beam is critical issue in an energy recovery linac. In particlar, the space charge effect on an electron bunch in the injector with lower than 5 - 10 MeV induces a large emittance growth. To suppress the emittance growth by such as an optimization of the solenoid magnets, a nonlinear effect should be clarified by a three dimensional tracking simulation. The cons is that it consumes a enormous simulation time. The approach is not suitable for a double loop circulation because the simulation time depends on the transport length. Therefore the beam dynamics and optics are calculated by a start-to-end (S2E) simulation, in which the simulation code is switched after the full acceleration. We used 'general particle tracking (GPT)' for injector electron beam and 'elegant' for a circulator electron beam.

Slides WEOAA03 [3.951 MB]

WEODA03

Design Concepts for the Large Hadron Electron Collider

electron, cavity, luminosity, collider

1942

M. Klein
The University of Liverpool, Liverpool, United Kingdom

A report is presented on the design concepts for a high luminosity electron-nucleon collider of 1.3 TeV centre of mass energy, realized with the addition of a 60 GeV electron ring or linear accelerator to the existing proton and ion LHC beam facility, comprising machine magnets, optics, interaction region, cryogenics, rf, civil engineering and further components of the LHeC. The report on behalf of the LHeC study team is a summary of the 2011 LHeC CDR and feedback received from an international review panel.

Slides WEODA03 [9.780 MB]

WEOAB02

FACET: The New User Facility at SLAC

electron, positron, plasma, wakefield

1953

C.I. Clarke, F.-J. Decker, R.A. Erickson, C. Hast, M.J. Hogan, R.H. Iverson, S.Z. Li, Y. Nosochkov, N. Phinney, J. Sheppard, U. Wienands, W. Wittmer, M. Woodley, G. Yocky
SLAC, Menlo Park, California, USA
A. Seryi
JAI, Oxford, United Kingdom

Funding: Work supported by the U.S. Department of Energy under contract number DE-AC02-76SF00515.
FACET (Facility for Advanced Accelerator and Experimental Tests) is a new User Facility at SLAC National Accelerator Laboratory. Its high power electron and positron beams make it a unique facility, ideal for beam-driven Plasma Wakefield Acceleration studies. The first 2 km of the SLAC linac produce 23 GeV, 3.2 nC electron and positron beams with short bunch lengths of 20 um. A final focusing system can produce beam spots 10um wide. User-aided Commissioning took place in summer 2011 and FACET will formally come online in early 2012. We present the User Facility, the current features, planned upgrades and the opportunities for further experiments.

Slides WEOAB02 [4.772 MB]

WEOBB03

Electron Bunch Profile Diagnostics in the Few fs Regime using Coherent Smith-Purcell Radiation

radiation, electron, diagnostics, vacuum

1970

N. Delerue
LAL, Orsay, France
R. Bartolini, G. Doucas, K. Pattle, C. Perry, A. Reichold, R. Tovey
JAI, Oxford, United Kingdom

Funding: John Fell Fund, University of Oxford
The rapid developments in the field of laser-driven particle acceleration hold the prospect of intense, highly relativistic electron bunches that are only a few fs long. The determination of the temporal profile of such a bunch presents new challenges. The use of a radiative process such as Smith-Purcell radiation (SPR), whereby the beam is made to radiate a small amount of e/m radiation and the temporal profile is then reconstructed from the measured spectral distribution of the radiation, is particularly promising in this respect. We summarize the advantages of SPR and present the design parameters of a forthcoming experiment at the FACET facility at SLAC with bunch lengths of the order of 60fs rms. We also discuss a new approach to the problem of the recovery of the ‘missing phase’, which is essential for the accurate reconstruction of the bunch profile.

Slides WEOBB03 [4.627 MB]

WEIB04

Accelertor-based Mega-science Projects in China and Their Impact on Economy

vacuum, ion, electron, radiation

1986

C. Zhang
IHEP Beijing, Beijing, People's Republic of China

Along with the rapid development of national economy in China, a number of accelerator based mega-science projects were constructed, such as the Beijing Electron-Positron Colliders (BEPC) and its major upgrade project (BEPCII), the Hefei Light Source (HLS), the Heavy Ion Research Facility in Lanzhou (HIRFL) and its Cooling Storage Rings (HIEFL-CSR), the Shanghai Synchrotron Radiation Facility (SSRF) and the Dragon-I induction linac. The Beijing Radioactive Ion Facility (BRIF) and the China Spallation Neutron Source (CSNS) are under construction. In this paper, China’s accelerator projects are briefly reviewed and applications of accelerators are reported. The paper emphasizes spinoff of the accelerator technology developed during R&D and construction of the projects. Collaboration between academia and industry on the projects are described. With some examples, the benefits experienced in the laboratory-industry collaboration and approach of its economic impact are illustrated.

Slides WEIB04 [14.012 MB]

WEPC002

RF Separator and Septum Layout Concepts for Simultaneous Beams to RIB and FEL Users at ARIEL

septum, dipole, FEL, electron

1998

Y.-C. Chao, C. Gong, S.R. Koscielniak
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada

A ½ MW capable CW electron linac is being designed and constructed at TRIUMF in support of the existing Rare Isotope Beam program. In the simplest configuration, the beam makes a single pass through three cryomodules to the RIB production targets. However, after the construction of a recirculation path, beam could make a second pass through two cryomodules with the RF phase advance adjusted to give energy recovery. Here it is proposed to time-interleave two bunch trains, and via an RF separator and septum, to direct one single-pass train to RIB production and the second train through the energy recovery ring that contains an IR FEL. It is also the intention, in single user mode, to use the ring as an energy doubler. This paper describes the RF separation scheme and options for the extraction optics that satisfy the requirements of “simultaneous” beams to two users.

WEPC005

Concept for Controlled Transverse Emittance Transfer within a Linac Ion Beam

emittance, ECR, solenoid, quadrupole

2007

L. Groening
GSI, Darmstadt, Germany

Generally the two transverse emittances of a linac beam are quite similar in size (round beam). However, injection into subsequent rings often imposes stronger limits for the upper allowed value to one of these emittances. Provision of flat linac beams (different transverse emittances) thus can considerable increase the injection efficiency into rings. Round-to-flat transformation has been already demonstrated for electron beams. It was also proposed for angular momentum dominated beams from Electron-Cyclotron-Resonance sources. We introduce a concept to extend the transformation to ion beams that underwent charge state stripping without requiring their extraction from an ECR source. The concept is of special interest for beams from low-charge-state / high-particle-current sources. It can be also applied to stripping of H⁻ to proton beams.

WEPC006

Upgrade Plans on the Superconducting Electron Accelerator S-DALINAC

recirculation, dipole, electron, extraction

2010

M. Kleinmann, R. Eichhorn, F. Hug, N. Pietralla
TU Darmstadt, Darmstadt, Germany

Funding: Work supported by DFG through SFB 634
The S-DALINAC is a superconducting recirculating electron accelerator with maximum design energy of 130 MeV operating in cw at 3 GHz. Even so the gradients of the superconducting cavities are well above design, their design quality factor of 3*10⁹ have not been reached so far, leading to higher heat transfer into the liquid helium than expected. Due to the limited cooling power of the cryo-plant being 120 W, the final energy achievable in cw operation is around 85 MeV, currently. In order to provide a cw beam with the designed final energy in the future, the installation of an additional recirculation path is projected. We will report on the beam-line and the magnet design for the new recirculation path. In addition, we will present the layout of two proposed scraper-systems which will be used to remove the halo of the electron beam allowing high precision coincidence experiments with very low background for nuclear physics in the future.

WEPC007

Large Energy Acceptance Dogleg for the European XFEL Injector

sextupole, focusing, quadrupole, controls

2013

N. Golubeva, V. Balandin, W. Decking
DESY, Hamburg, Germany

The option to install two injectors is foreseen at the European XFEL Facility. The injectors will be located on top of each other in the same building, both with the offset of 2.75 m with respect to the main linac axis. The translation system (dogleg) from the injector axis to the main linac axis has to fulfill very tight requirements of the chromatic properties, because the energy chirp required for the downstream bunch length compression in magnetic chicanes will be created upstream in the injector linac. In this paper we present such an large energy acceptance dogleg and discuss the optical symmetries which form the basis of its design.

WEPC012

Steering-corrected 88 MHz QWRs for SARAF Phase II

cavity, proton, simulation, lattice

2028

J. Rodnizki, J. Ashkenazy, D. Berkovits, Z. Horvitz
Soreq NRC, Yavne, Israel
A. Kolomiets, B. Mustapha, P.N. Ostroumov
ANL, Argonne, USA

Funding: This work is partially supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357.
SARAF phase II linac is designed for 5 mA 40 MeV proton and deuteron beams. One option is to base the design on Quarter Wave Resonators (QWR). It is suggested to compensate the QWR non-symmetric magnetic field component by introducing a drift tube face tilt angle*. Here we explore the applicability of this steering correction scheme to the acceleration of a CW high current low β light ion beam in an end-to-end 88 MHz QWR lattice. This can serve as a case study for multi-megawatt machines that are currently being designed by ANL. An analytical approximation is used to evaluate the on-axis beam steering behavior. Two 88 MHz QWR cavities, β=0.08 and 0.15, were designed, field and beam dynamics were simulated and optimized. Using the tube face tilt angle concept the beam steering along a QWR can be reduced to the order of 0.1 mrad. Beam dynamics lattice examination including error analysis demonstrated an efficient high performance 40 MeV linac based on 3 superconducting modules with 19 QWRs (Ep < 35 MV/m and Bp < 70 mT). The fields obtained at recent ANL tests for a 73 MHz QWR (70 MV/m and 10⁵ mT) imply that Ep is not a real limiting factor.
* P.N. Ostroumov and K. W. Shepard, PRST-AB 4, 110101 (2001).

WEPC014

Beam Dynamics Simulations of the PIAVE-ALPI Linac

simulation, cavity, rfq, diagnostics

2034

M. Comunian, E. Fagotti, F. Grespan, A. Palmieri, A. Pisent, C. Roncolato
INFN/LNL, Legnaro (PD), Italy

At the Legnaro National Laboratories it is operating a SuperConducting linac for nuclear studies. The ALPI linac is injected either by a XTU tandem, up to 14 MV, or by the s-c PIAVE injector, made with 2 SC-RFQ. The main part of the linac (at the present 64 cavities for a total voltage up to 48 MV) is build up in two branches connected by an achromatic and isochronous U-bend. The PIAVE-ALPI complex is able to accelerate beams up to A/q = 7. The layout of the linac ALPI is, from the point of beam dynamics, quite complex due the presence of RFQs, cavities, dipoles, magnets, etc. These elements behaviors are entirely not linear, so a small change on the settings can induce a big change in the Linac beam dynamics. An automatic tuning procedure and a full field maps description are mandatory to handle a so high number of active components. The program used at this scope is TraceWin that is able to do an envelope simulation and a full multiparticles simulation.

WEPC018

Self-focusing Effects in Compact C-band Standing-wave Accelerating Structure for X-ray Imaging Applications

focusing, bunching, electron, accelerating-gradient

2046

H.R. Yang, M.-H. Cho, S.H. Kim, W. Namkung, S.J. Park
POSTECH, Pohang, Kyungbuk, Republic of Korea
J.-S. Oh
NFRI, Daejon, Republic of Korea

In electron RF linacs for industrial X-ray imaging applications, compact structures are preferred for mobility. The electron beam spot size of 1 – 2 mm is required for the spatial resolution of images at the X-ray conversion target. Applying self-focusing effects to the accelerating structure, external magnets can be removed and then the accelerator system becomes more compact. We design a C-band electron linac, which is capable of producing 6-MeV, 80-mA pulsed electron beams with an RF power of 1.5 MW. It uses a bi-periodic and on-axis-coupled accelerating structure with a built-in bunching section. It uses the π/2-mode standing-waves. The first bunching cell has an asymmetric geometry which maximizes the RF phase focusing. On the other hand, the normal cells are designed for the electrostatic focusing to be maximized. In this paper, we present design details of the accelerating cells and the beam dynamics simulation by the PARMELA code.

WEPC021

Optical Design of the Proton Beam Lines for the Neutron Research Complex INR RAS and Medical Application

proton, neutron, target, beam-losses

2049

M.I. Grachev, E.V. Ponomareva
RAS/INR, Moscow, Russia

The optical design for the layout of the beam lines for the neutron research complex INR RAS and medical application on the basis of the Linear accelerator are presented here. The proposed schemes have been realized at the INR RAS. The necessary size and shape of the proton beam at the location of the neutron target are obtained. Methods and results for the tuning of the high current beams are presented in this paper.

WEPC036

Coherent Synchrotron Radiation Source Based on an Isochronous Accumulator Ring with Femtosecond Electron Bunches

betatron, gun, radiation, lattice

2085

N.Y. Huang
NTHU, Hsinchu, Taiwan
H. Hama, F. Hinode, S. Kashiwagi, M. Kawai, X. Li, F. Miyahara, T. Muto, K. Nanbu, Y. Tanaka
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
W.K. Lau
NSRRC, Hsinchu, Taiwan

A compact isochronous accumulator ring has been studied as a source of coherent synchrotron radiation (CSR) at a wavelength region from THz to GHz. Since the thermionic rf gun is substantially stable in general, we anticipate a bunch train of very short electron pulses can be provided satisfactorily by means of velocity bunching. Careful numerical simulations show possibility of the bunch length of much less than 100 fs with a bunch charge of 20 pC, which will contain sufficiently large form factor for production of CSR at the wavelengths longer than ~ 0.1 mm. The coherent THz radiation of high average power will be achieved if the short bunches can be circulated in the accumulator ring without bunch lengthening. This paper will describe the optimization of thermionic injector to produce femtosecond bunches in addition to study of the lattice designing of complete isochronous optics for the accumulator ring.

WEPC038

Beam Line Design and Beam Measurement for TPS Linac

quadrupole, single-bunch, diagnostics, booster

2091

K.L. Tsai, H.-P. Chang, C.-T. Chen, C.-S. Fann, K.T. Hsu, S.Y. Hsu, C.-Y. Liao, K.-K. Lin, H.M. Shih
NSRRC, Hsinchu, Taiwan
K. Dunkel, C. Piel
RI Research Instruments GmbH, Bergisch Gladbach, Germany

A beam line for examining the beam quality of TPS (Taiwan Photon Source) linac was designed and constructed in NSRRC. Beam parameters, such as energy, emittance and charge etc., are verified by using the equipments setup in the beam line for this purpose. The lattice design and its manipulation for the parameter measurements are presented in this report. Preliminary results and the tools associating with the measurement are briefly described.

WEPC039

Modelling of the FETS MEBT Line using GPT

emittance, simulation, rfq, ion

2094

D.C. Plostinar
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
R. Enparantza, M. Larrañaga
Fundación TEKNIKER, Eibar (Gipuzkoa), Spain

The Front End Test Stand project (FETS) currently under construction at Rutherford Appleton Laboratory (RAL) will accelerate a 60 mA, 2 ms, 50 pps H⁻ beam up to 3 MeV. It consists of an H⁻ ion source, a three-solenoid low energy beam transport line (LEBT), an RFQ and a medium energy beam transport line (MEBT) with a fast-slow beam chopping system. As part of the MEBT development, a GPT simulation model has been prepared. The aim is to analyse and understand the transport of intense beams and the beam behaviour in the space-charge dominated regime. The beam quality is then evaluated in terms of RMS emittance growth, beam loss, chopping efficiency and halo development. Results previously obtained with different simulation codes are discussed throughout the paper.

WEPC040

Initial 2D Investigations into the Design and Parameters of an EM Quadrupole for FETS

quadrupole, simulation, ion, rfq

2097

M. Larrañaga, R. Enparantza
Fundación TEKNIKER, Eibar (Gipuzkoa), Spain
D.C. Plostinar
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

The Medium Energy Beam Transport (MEBT) line for the Front End Test Stand (FETS) at Rutherford Appleton Laboratory (RAL) consists of a number of quadrupoles, re-bunching cavities and a fast-slow chopping system with dedicated beam dumps, as well as diagnostics. The type and design of the quadrupoles to be used merits special attention. Due to space restrictions, a hybrid quadrupole solution has been proposed in the past. However, because of the limited range of field adjustability achievable, this approach is not ideal. In this paper, a very preliminary investigation of an electromagnetic quadrupole (EMQ) design is presented. Magnetic simulations results performed with a 2D simulation code will be discussed including magnet optimisation details.

WEPC041

Conceptual Design of a New 800 MeV H⁻ Linac for ISIS Megawatt Developments

cavity, DTL, quadrupole, rfq

2100

D.C. Plostinar, C.R. Prior, G.H. Rees
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

Several schemes have been proposed to upgrade the ISIS Spallation Neutron Source at Rutherford Appleton Laboratory (RAL). One scenario is to develop a new 800 MeV, H⁻ linac and a ~3 GeV synchrotron, opening the possibility of achieving several MW of beam power. In this paper the design of the 800 MeV linac is outlined. It consists of a 3 MeV Front End similar to the one now under construction at RAL (the Front End Test Stand -FETS). Above 3 MeV, a 324 MHz DTL will be used to accelerate the beam up to ~75 MeV. At this stage a novel collimation system will be added to remove the halo and the far off-momentum particles. To achieve the final energy, a 648 MHz superconducting linac will be employed using three families of elliptical cavities with transition energies at ~196 MeV and ~412 MeV. Alternative designs are also being investigated.

WEPC087

Dark Current Simulations for the Cornell ERL

cavity, electron, simulation, cryomodule

2214

C.E. Mayes, C.S. Chiu, G.H. Hoffstaetter, V.O. Kostroun, D. Sagan
CLASSE, Ithaca, New York, USA
L.M. Nash
North Carolina University, Chapel Hill, North Carolina, USA

Funding: Supported by NSF award DMR-0807731
Charged particles unintentionally transported through an accelerator, collectively called the dark current, can be lost in the beam chamber and create a radiation hazard for both equipment and personnel. Here we simulate the creation of particles by field emission in the superconducting accelerating cavities of the Cornell Energy Recovery Linac, and track them to their loss points. These lost particles can then be used to simulate background radiation. The presented calculations are therefore an essential step in the design of appropriate radiation-shielding of components around the linac.

WEPC092

Moment-Based Simulation of the S-DALINAC Recirculations*

simulation, recirculation, quadrupole, cavity

2223

S. Franke, W. Ackermann, T. Weiland
TEMF, TU Darmstadt, Darmstadt, Germany
R. Eichhorn, F. Hug, C. Klose, N. Pietralla, M. Platz
TU Darmstadt, Darmstadt, Germany

Funding: Work supported by DFG under contract SFB 634.
The Superconducting Linear Accelerator S-DALINAC installed at the institute of nuclear physics (IKP) at TU Darmstadt is designed as a re-circulating linear accelerator. The length of the beam line and the numerous accelerating structures as well as dipole and quadrupole magnets require a highly efficient numerical simulation tool in order to assist the operators by providing a detailed and almost instantaneous insight into the actual machine status. A suitable approach which enables a fast online calculation of the beam dynamics is given by the so-called moment approach where the particle distribution is represented by means of a discrete set of moments or by multiple discrete sets of moments in a multi-ensemble environment. Following this approach the V-Code simulation tool has been implemented at the Computational Electromagnetics Laboratory (TEMF) at TU Darmstadt. In this contribution an overview of the numerical model is presented together with new V-Code simulation results regarding the S-DALINAC recirculation sections.

WEPC099

Coupler Design and Optimization by GPU-Accelerated DG-FEM

HOM, simulation, scattering, higher-order-mode

2244

C. Potratz, H.-W. Glock, U. van Rienen
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany

The numerical optimization of rf-components like couplers is a common task during the design phase of particle accelerators. Typically, these optimizations involve the simulation of a multitude of very similar structures with minor geometric variations. Nevertheless, this process is in its entire extend rather demanding on both the invested time and hardware budget. With recent advancements in the field of numerical electromagnetic field simulation and consumer graphic processors, an interesting alternative for the time-consuming simulation part of the optimization is available. In this contribution we show, how the Discontinuous Galerkin FEM method in conjunction with consumer graphic cards can be used to build moderately prized cluster solutions for the parallel simulation of rf-components. The contribution will mainly focus on, but is not limited to, Higher Order Mode couplers as a typical application example, where the DG-FEM method accelerated by a graphic processor might be used to significantly reduce the overall time necessary for the optimization.

WEPC134

Unified Accelerator Modeling Using the Bmad Software Library

simulation, lattice, controls, photon

2310

D. Sagan, I.V. Bazarov, J.Y. Chee, J.A. Crittenden, G. Dugan, K. Finkelstein, G.H. Hoffstaetter, C.E. Mayes, S. Milashuk, D. L. Rubin, J.P. Shanks
CLASSE, Ithaca, New York, USA
R. Cope
CSU, Fort Collins, Colorado, USA

Funding: Work supported by the National Science Foundation and by the US Department of Energy under contract numbers PHY-0734867 and DE-FC02-08ER41538.
The Bmad software library has proved to be a useful tool for accelerator simulations owing to its modular, object-oriented design. It is now used in a number of design, simulation and control programs at the Cornell Laboratory for Accelerator-based Sciences and Education. Work is ongoing to expand Bmad in a number of directions. One aim is tohave a complete framework in order to simulate Cornell's Energy Recovery Linac from Gun cathode (including space-charge) to photon generation to photon tracking through to the x-ray experimental end stations. Other work includes synchrotron radiation tracking including reflections from the vacuum chamber walls which is useful for electron cloud investigations, spin tracking, beam break-up instability, intra-beam scattering, etc. This paper will discuss the current state of the Bmad software along with the long-term goals.

WEPC144

Beam Monitor Deformation by Tohoku Earthquake and its Recovery Project

cavity, vacuum, DTL, impedance

2328

A. Miura, K. Hasegawa, H. Oguri, N. Ouchi
JAEA/J-PARC, Tokai-mura, Japan
Z. Igarashi, M. Ikegami, T. Miyao
KEK, Ibaraki, Japan

On March 11, 2011, the biggest earthquake occurred at Tohoku and North Kanto area in Japan. This earthquake and related ones have attacked J-PARC accelerators and caused the big damage. As for the linac beam monitors, some commissioning tools which were installed in the linac had damage and the air leakage was observed. In the first step of the recovery work, we checked the damage and put the emergency treatment for vacuum of the cavities. All beam monitors were observed, the leak from the vacuum devices was tested and the conduction of the signal cables was measured to compare the previous performance. In the next step, we started to order the new devices which should be replaced and to obtain the calibration data. We found the leakage from the phase monitors. The earthquake caused the crack and deformation at the welded points between the metallic parts and ceramic parts. And a wire of the profile monitor was broken while the beam position monitors have no damage. We are continuing this recovery work ongoingly.

WEPC163

A New Embedded Radiation Monitor System for Dosimetry at the European XFEL

radiation, undulator, neutron, controls

2364

F. Schmidt-Föhre, D. Nölle, R. Susen, K. Wittenburg
DESY, Hamburg, Germany
L. Fröhlich
ELETTRA, Basovizza, Italy

The upcoming European XFEL will be built at a length of approx. 3.4 km between the campus of the Deutsches Elektronen-Synchrotron DESY at Hamburg and Schenefeld at Schleswig-Holstein for commissioning in 2015. The XFEL utilizes various electronic systems for machine control, diagnostics and safety. To achieve a cheap and compact accelerator construction, the beam pipe and its nearby electronic supply systems are located inside the same tunnel, charged by an evident amount of radiation in certain sections of the XFEL. To insure the lifecycle and function of electronics and magnetic structures like undulators in these XFEL radiation fields, all electronic systems located inside the tunnel will be sufficiently shielded according to pre-estimated radiation levels. In addition, these electronics and the undulator parts will be monitored for the impact of Gamma- and Neutron-radiation by a new versatile and compact radiation monitor system. It measures the accumulated dose in the electronic cabinets along the XFEL to ensure an exchange of radiated parts before significant radiation damage occurs. First prototype measurements at different radiation sources will be presented.

WEPC171

Requirements of a Beam Loss Monitoring System for the CLIC Two Beam Modules

photon, beam-losses, simulation, monitoring

2385

S. Mallows
The University of Liverpool, Liverpool, United Kingdom
E.B. Holzer, A.P. Mechev, J.W. van Hoorne
CERN, Geneva, Switzerland
C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

he Compact Linear Collider (CLIC) study investigates the feasibility of a high-energy electron-positron linear collider optimized for a centre of mass energy of 3 TeV. To achieve the high accelerating gradients, the RF power is produced by a novel two-beam acceleration method in which a decelerating drive beam supplies energy to the main accelerating beam. The linacs are arranged in modular structures referred to as the two beam modules which cover 42 km of beamline. Beam losses from either beam can have severe consequences due to the high intensity drive beam and the high energy, small emittance main beam. This paper presents recent developments towards the design of a Cherenkov fiber BLM system and discusses its ability to distinguish losses originating from either beam.

WEPO012

Calculation, Design and Manufacturing of a Resistive Quadrupole for the ESS-Bilbao Transfer Lines

quadrupole, power-supply, acceleration, DTL

2418

I. Rodríguez, F.J. Bermejo, J.L. Munoz, D. de Cos
ESS Bilbao, Bilbao, Spain

The first stage of the ESS-Bilbao LINAC will accelerate H⁺ and H− high current beams up to 50 MeV for different applications. After the last acceleration step in the DTL, the beam will either be transported to the experimental laboratories by the means of several transfer lines, or continue to a further acceleration step in spoke cavities. The first design of one of the quadrupoles that focus the beam along the transfer lines is presented. The quadrupoles will have an aperture of 63 mm and 20 T/m maximum gradient, featuring a short iron yoke of 100 mm. All the quadrupoles of the transfer lines are expected to be similar in order to simplify the design and manufacturing processes. The iron yoke is small and highly saturated, and an optimization of the 3D harmonics in the load-line is developed to fulfil the field quality specifications. The required current density is high (about 8.2 A/mm2), therefore a water cooled hollow conductor is used to cool down the coils. The cooling and power supply requirements are calculated in this paper. The most important manufacturing indications are also presented.

WEPO017

Status of CLIC Magnets Studies

quadrupole, permanent-magnet, solenoid, acceleration

2433

M. Modena
CERN, Geneva, Switzerland
A.S. Vorozhtsov
JINR, Dubna, Moscow Region, Russia

R&D Magnets activities for CLIC Project have now entered a new phase with the design & manufacturing of several prototypes investigating the most challenging aspects of the CLIC Project. As concerning the CLIC Magnet System, challenges can be related to pure technical aspects (e.g. the Final Focus QD0 quadrupole where a gradient of more than 550 T/m is requested) or to industrial production choices (e.g. the Main Beam Quadrupoles where compactness and high tolerances are requested for the mechanical assembly, or the Drive Beam Quadrupoles where a productions of more than 40000 units is needed). In this paper the key aspects of the magnets under studies such as the Drive Beam, Main Beam and the Final Focus quadrupoles will be presented and discussed. Results on prototypes under assembly and measured performances will also be addressed.

WEPO018

Status of the New Linac4 Magnets at CERN

quadrupole, solenoid, DTL, simulation

2436

Th. Zickler, F. Borgnolutti, O. Crettiez, A. Newborough, L. Vanherpe
CERN, Geneva, Switzerland
A.S. Vorozhtsov
JINR, Dubna, Moscow Region, Russia

Linac4 is a new H⁻ linear accelerator at CERN replacing Linac2 as injector to the PS Booster. Almost 100 electro-magnets of different types are needed for the Linac4 project. Following a detailed analysis of the requirements and constraints, several magnet designs have been studied and are well advanced. This paper presents the design considerations, main parameters and characteristics of the new Linac4 magnets and summarizes the present status.

WEPO030

Fabrication and Testing of the First Magnet Package Prototype for the SRF Linac of LIPAc

solenoid, cavity, SRF, vacuum

2463

S. Sanz, J. Calero, F.M. De Aragon, J.L. Gutiérrez, I. Moya, I. Podadera, F. Toral, J.G.S. de la Gama
CIEMAT, Madrid, Spain
N. Bazin, P. Bosland, P. Bredy, N. Grouas, P. Hardy, V.M. Hennion, J. Migne, F. Orsini, B. Renard
CEA/DSM/IRFU, France
G. Disset, J. Relland
CEA, Gif-sur-Yvette, France
H. Jenhani
CEA/IRFU, Gif-sur-Yvette, France
E.N. Zaplatin
FZJ, Jülich, Germany

Funding: Work partially supported by Spanish Ministry of Science and Innovation under project AIC10-A-000441 and ENE2009-11230.
The IFMIF-EVEDA accelerator will be a 9 MeV, 125 mA CW deuteron accelerator which aims to validate the technology that will be used in the future IFMIF accelerator. The SRF Linac design is based on superconducting Half Wave Resonators (HWR) cavities operating at 4.4 K. Due to space charge associated to the high intensity beam, a short, but strong, superconducting focusing magnet package is necessary between cavities. The selected configuration has been a superconducting NbTi solenoid acting as a magnetic lens and a concentric outer solenoid in antiparallel configuration to reduce the dangerous stray field on the cavities. The selected arrangement for the steerers is a pair of parallel racetrack coils for each vertical and horizontal axis. This paper describes the manufacturing techniques of the different coils, and the test realized in warm and cold conditions, with special attention to the training test of the main solenoid, as the nominal working point in the load line is very high (86.2%).

WEPO035

Thermal Performance of the S1-Global Cryomodule for ILC

cavity, cryomodule, radiation, vacuum

2472

N. Ohuchi, M. Akemoto, S. Fukuda, K. Hara, H. Hayano, N. Higashi, E. Kako, Y. Kojima, Y. Kondo, T. Matsumoto, S. Michizono, T. Miura, H. Nakai, H. Nakajima, K. Nakanishi, S. Noguchi, T. Saeki, M. Satoh, T. Shidara, T. Shishido, T. Takenaka, A. Terashima, N. Toge, K. Tsuchiya, K. Watanabe, S. Yamaguchi, A. Yamamoto, Y. Yamamoto, K. Yokoya
KEK, Ibaraki, Japan
T.T. Arkan, S. Barbanotti, H. Carter, M.S. Champion, A. Hocker, R.D. Kephart, J.S. Kerby, D.V. Mitchell, T.J. Peterson, Y.M. Pischalnikov, M.C. Ross
Fermilab, Batavia, USA
A. Bosotti, C. Pagani, R. Paparella, P. Pierini
INFN/LASA, Segrate (MI), Italy
D. Kostin, L. Lilje, A. Matheisen, W.-D. Möller, N.J. Walker, H. Weise
DESY, Hamburg, Germany

The S1-Global program is the international research collaboration among INFN, FNAL, DESY, SLAC and KEK as one of the GDE R&D for construction of ILC. The S1-Global cryomodule consists of two half-size cryomodules of 6 meter. One was designed by IFNF, and it contained two FNAL cavities and two DESY cavities. The associated components, like input couplers and RF cables, were same as the TTF-III cryomodule. The other was designed by KEK, and the thermal design was based on the TTF-III cryomodule. This cryomodule contains four KEK cavities with the associated components which were designed by KEK. For characterizing the thermal performances of two cryomodules, the static heat load and the temperature profiles of the cold components were measured. The temperature profiles of the components were compared between two cryomodules and the static heat load was evaluated with the design values of the cryomodules. The dynamic losses of the DESY, FNAL and two KEK cavities at their maximum operative gradients were measured and, with the measured losses, Q values were calculated. In this paper, we will make the summary of the thermal measurements of the S1-Global cryomodule.

WEPS008

Operation Status and Future Plan of J-PARC Main Ring

extraction, beam-losses, kicker, betatron

2499

T. Koseki
KEK, Ibaraki, Japan

The J-PARC Main Ring (MR) has started users operation since 2009. The MR has two beam extraction systems. One is a fast extraction (FX) system for beam delivery to the neutrino beam line of the Tokai-to-Kamioka (T2K) experiment, and the other is a slow extraction (SX) system for beam delivery to the hadron experimental hall. For the T2K experiment, the maximum beam power of 145 kW is delivered continuously. For users of the hadron experimental hall, the beam power of 3 kW is delivered with extraction efficiency of 99.5%. In this paper, status of the high power beam operation of the MR is presented. Future prospect for increasing beam intensity is also discussed.

WEPS017

Plans for the Upgrade of the LHC Injectors

injection, synchrotron, electron, booster

2517

R. Garoby, S.S. Gilardoni, B. Goddard, K. Hanke, M. Meddahi, M. Vretenar
CERN, Geneva, Switzerland

The LHC Injectors Upgrade (LIU) project has been launched at the end of 2010 to prepare the CERN accelerator complex for reliably providing beam with the challenging characteristics required by the high luminosity LHC until at least 2030. Based on the work already started on Linac4, PS Booster, PS and SPS, the LIU project coordinates studies and implementation, and interfaces with the High Luminosity LHC (HL-LHC) project which looks after the upgrade of the LHC itself, expected by the end of the present decade. The anticipated beam characteristics are described, as well as the status of the studies and the solutions envisaged for improving the injector performances.

WEPS019

Study of a Rapid Cycling Synchrotron to Replace the CERN PS Booster

injection, extraction, booster, lattice

2523

K. Hanke, O. Aberle, M. E. Angoletta, B. Balhan, W. Bartmann, M. Benedikt, J. Borburgh, D. Bozzini, C. Carli, P. Dahlen, T. Dobers, M. Fitterer, R. Garoby, S.S. Gilardoni, B. Goddard, J. Hansen, T. Hermanns, M. Hourican, S. Jensen, A. Kosmicki, L.A. Lopez Hernandez, M. Meddahi, B. Mikulec, A. Newborough, M. Nonis, S. Olek, M.M. Paoluzzi, S. Pittet, B. Puccio, V. Raginel, I. Ruehl, H.O. Schönauer, L. Sermeus, R.R. Steerenberg, J. Tan, J. Tückmantel, M. Vretenar, M. Widorski
CERN, Geneva, Switzerland

CERN’s proton injector chain is undergoing a massive consolidation and upgrade program in order to deliver beams meeting the needs of the LHC Luminosity Upgrade. As an alternative to the upgrade of the existing Proton Synchrotron Booster (PSB), the construction of a Rapid Cycling Synchrotron (RCS) has been studied. This machine would replace the PSB and deliver beams to the LHC as well as to CERN’s rich fixed-target physics program. This paper summarizes the outcome of the feasibility study along with a tentative RCS design.

WEPS022

Ions for LHC: Performance of the Injector Chain

ion, luminosity, injection, proton

2529

D. Manglunki, M. E. Angoletta, P. Baudrenghien, G. Bellodi, A. Blas, T. Bohl, C. Carli, E. Carlier, S. Cettour Cave, M. Chanel, K. Cornelis, H. Damerau, A. Findlay, S.S. Gilardoni, S. Hancock, J.M. Jowett, D. Kuchler, S. Maury, E. Métral, S. Pasinelli, M. Schokker, G. Tranquille, B. Vandorpe, U. Wehrle, J. Wenninger
CERN, Geneva, Switzerland

The first LHC Pb ion run took place at 1.38 A TeV/c per beam in autumn 2010. After a short period of running-in, the injector chain was able to fill the collider with up to 137 bunches per ring, with an intensity of 10⁸ Pb ions/bunch, about 50% higher than the design value. This yielded a luminosity of 3E25 Hz/cm², allowing the experiments to accumulate just under 10 inverse microbarn each during the four week run. We review the performance of the individual links of the injector chain, and address the main issues limiting the LHC luminosity, in view of reaching 10²6 Hz/cm² in 2011, and substantially beyond when the LHC energy increases after the long shutdown in 2013-14.

WEPS024

Beta Beams: An Accelerator-based Facility to Explore Neutrino Oscillation Physics

ion, target, ECR, acceleration

2535

E.H.M. Wildner, E. Benedetto, T. De Melo Mendonca, C. Hansen, T. Stora
CERN, Geneva, Switzerland
D. Berkovits
Soreq NRC, Yavne, Israel
G. Burt, A.C. Dexter
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
A. Chancé, J. Payet
CEA/DSM/IRFU, France
M. Cinausero, G. De Angelis, F. Gramegna, T. Marchi, G.P. Prete
INFN/LNL, Legnaro (PD), Italy
G. Collazuol
Univ. degli Studi di Padova, Padova, Italy
F. Debray, C. Trophime
GHMFL, Grenoble, France
T. Delbar, T. Keutgen, M. Loiselet, S. Mitrofanov
UCL, Louvain-la-Neuve, Belgium
G. Di Rosa
INFN-Napoli, Napoli, Italy
M. Hass, T. Hirsch
Weizmann Institute of Science, Physics, Rehovot, Israel
I. Izotov, S. Razin, V. Skalyga, V. Zorin
IAP/RAS, Nizhny Novgorod, Russia
L.V. Kravchuk
RAS/INR, Moscow, Russia
T. Lamy, L. Latrasse, M. Marie-Jeanne, T. Thuillier
LPSC, Grenoble, France
M. Mezzetto
INFN- Sez. di Padova, Padova, Italy
A.V. Sidorov
BINP SB RAS, Protvino, Moscow Region, Russia
P. Sortais
ISN, Grenoble, France
A. Stahl
RWTH, Aachen, Germany

Funding: This contribution is a project funded by European Community under the European Commission Framework Programme 7 Design Study: EUROnu, Project Number 212372.
The recent discovery of neutrino oscillations, has implications for the Standard Model of particle physics (SM). Knowing the contribution of neutrinos to the SM, needs precise measurements of the parameters governing the neutrino oscillations. The EUROν Design Study will review three facilities (the so-called Super-Beams, Beta Beams and Neutrino Factories) and perform a cost assessment that, coupled with the physics performance, will give means to the European research authorities to make a decision on future European neutrino oscillation facility. "Beta Beams" produce collimated pure electron (anti-)neutrino by accelerating beta active ions to high energies and having them decay in a storage ring. EUROν Beta Beams are based on CERN’s infrastructure and existing machines. Using existing machines is an advantage for the cost evaluation, however, this choice is also constraining the Beta Beams. Recent work to make the Beta Beam facility a solid option will be described: production of Beta Beam isotopes, the 60 GHz pulsed ECR source development, integration into the LHC-upgrades, ensure the high intensity ion beam stability, and optimizations to get high neutrino fluxes.

WEPS031

Future Heavy Ion Linacs at GSI

ion, rfq, cavity, heavy-ion

2550

W.A. Barth, G. Clemente, L.A. Dahl, S. Mickat, B. Schlitt, W. Vinzenz
GSI, Darmstadt, Germany

The UNILAC-upgrade program for FAIR will be realized in the next three years; the required U²⁸⁺-beam intensity of 15 emA (for SIS 18 injection). The replacement of the Alvarez-DTL by a new high energy linac is advised to provide a stable operation for the next decades. An additional linac-upgrade option sufficient to boost the beam energy up to 150 MeV/u may help to reach the desired heavy ion intensities in the SIS 100. The SHIP-upgrade program has also to be realized until 2011, such that an enhanced primary beam intensity at the target is available. It is planned to build a new cw-heavy ion-linac behind the present high charge state injector. This linac should feed the GSI flagship experiments SHIP and TASCA, as well as material research, biophysics and plasma physics experiments in the MeV/u-area. The whole injector family is housed by the existing constructions. Different layout scenarios of a multipurpose high intensity heavy ion facility will be presented.

WEPS032

Conceptual Study for the New HE-Linac at GSI

cavity, injection, DTL, acceleration

2553

G. Clemente, W.A. Barth, B. Schlitt
GSI, Darmstadt, Germany

The commissioning of the first three modules of the FAIR accelerator facility is planned to be completed in 2016. At that time the DTL section of the UNILAC will be more than 40 years old. Different proposals for a new high intensity, heavy ion linac which will replace the ALVAREZ DTL as synchrotron injector are under discussion. This new High Energy-UNILAC will be design accordingly to the advanced FAIR requirements and will allow for complete and reliable multi-ion-operation for at least the next 30 years. In a first step it is foreseen to replace the first two DTL cavity, up to 4.7 AMeV. 4 IH cavities will be used to accelerate U⁴⁺ to 3 AMeV and, after gas stripping, another cavity will provide the second step of acceleration for U³⁸⁺ to 4.77 AMeV. For the next upgrade different options concerning the injection energy are under investigation. The main target is to provide a higher charge state and a higher injection energy to increase the life time of the heavy ion beam inside the synchrotron. The paper presents the beam dynamics and RF investigation for the first upgrade together with a conceptual study design for the complete replacement of the GSI ALVAREZ DTL.

WEPS034

A CW RFQ Prototype

rfq, simulation, impedance, vacuum

2559

U. Bartz, A. Schempp
IAP, Frankfurt am Main, Germany

A short RFQ prototype was built for RF-tests of high power RFQ structures. We will study thermal effects and determine critical points of the design. HF-simulations with CST Microwave Studio and measurements were done. The cw-tests with 20 kW/m RF-power and simulations of thermal effects with ALGOR were finished successfully. The optimization of some details of the HF design is on focus now. First results and the status of the project will be presented.

WEPS036

First Coupled CH Power Cavity for the FAIR Proton Injector

cavity, coupling, proton, DTL

2565

R. M. Brodhage, C. Fix, H. Podlech, U. Ratzinger
IAP, Frankfurt am Main, Germany
G. Clemente, L. Groening
GSI, Darmstadt, Germany

For the research program with cooled antiprotons at FAIR a dedicated 70 MeV, 70 mA proton injector is required. The main acceleration of this room temperature linac will be provided by six CH cavities operated at 325 MHz. Each cavity will be powered by a 2.5 MW Klystron. For the second acceleration unit from 11.5 MeV to 24.2 MeV a 1:2 scaled model has been built. Low level RF measurements have been performed to determine the main parameters and to prove the concept of coupled CH cavities. For this second tank technical and mechanical investigations have been performed in 2010 to develop a complete technical concept for the manufacturing. In Spring 2011, the construction of the first power prototype has started. The main components of this cavity will be ready for measurements in summer 2011. At that time, the cavity will be tested with a preliminary aluminum drift tube structure, which will allow precise frequency and field tuning. This paper will report on the recent technical development and achievements. It will outline the main fabrication steps towards that novel type of proton DTL. Also first low level RF measurements are expected.

WEPS037

RF Design of a 325 MHz 4-ROD RFQ

dipole, rfq, simulation, quadrupole

2568

B. Koubek, A. Schempp, J.S. Schmidt
IAP, Frankfurt am Main, Germany
L. Groening
GSI, Darmstadt, Germany

Usually 4-ROD Radio Frequency Quadrupoles (RFQ) are built for frequencies up to 216 MHz. For higher frequencies 4-VANE structures are more common. The advantages of 4-Rod structures, the greater flexibility for tuning and being more comfortable for maintenance, are motivating the development of a 4-Rod RFQ for higher frequencies than 216 MHz. In particular a 325 MHz RFQ with an output energy of 3 MeV is needed for the proton linac for the FAIR project of GSI. This paper reports about the design studies and the latest developments of this RFQ.

WEPS039

General Layout of the 17 MeV Injector for MYRRHA

cavity, rfq, proton, ECR

2574

H. Podlech, M. Busch, F.D. Dziuba, H. Klein, D. Mäder, U. Ratzinger, A. Schempp, R. Tiede, C. Zhang
IAP, Frankfurt am Main, Germany
M. Amberg
HIM, Mainz, Germany

Funding: European Union FP7 MAX Contract Number 269565
The MYRRHA Project (Multi Purpose Hybrid Reactor for High Tech Applications) at Mol/belgium will be a user facility with emphasis on research with neutron generated by a spallation source. One main aspect is the demonstration of nuclear waste technology using an accelerator driven system. A superconducting linac delivers a 4 mA, 600 MeV proton beam. The first accelerating section is covered by the 17 MeV injector. It consists of a proton source, an RFQ, two room temperature CH cavities and 4 superconducting CH-cavities. The initial design has used an RF frequency of 352 MHz. Recently the frequency of the injector has been set to 176 MHz. The main reason is the possible use of a 4-rod-RFQ with reduced power dissipation and energy, respectively. The status of the overall injector layout including cavity design is presented.

Poster WEPS039 [2.281 MB]

WEPS041

Tuning of the New 4-Rod RFQ for FNAL

rfq, resonance, simulation, pick-up

2580

J.S. Schmidt, B. Koubek, A. Schempp
IAP, Frankfurt am Main, Germany

For the injector upgrade at FNAL a 4-rod Radio Frequency Quadrupole (RFQ) with a resonance frequency of 200 MHz has been build. With this short structure of only 1.3 m a very compact injector design has been realized. Simulations with CST Microwave Studio® were performed for the design. Their results leading to the RF characterizations of the RFQ and the final RF setup which has been accomplished at IAP of the Goethe-University Frankfurt are presented in this paper.

WEPS043

From EUROTRANS to MAX: New Strategies and Approaches for the Injector Development

rfq, DTL, cavity, emittance

2583

C. Zhang, H. Klein, D. Mäder, H. Podlech, U. Ratzinger, A. Schempp, R. Tiede
IAP, Frankfurt am Main, Germany

Funding: The research leading to these results has received funding from the European Atomic Energy Community’s (Euratom) Seventh Framework Programme FP7/2007-2011 under grant agreement n° [269565].
As the successor of the EUROTRANS project, the MAX project is aiming to continue the R&D effects for a European Accelerator-Driven System and to bring the conceptual design to reality. The layout of the driver linac for MAX will follow the reference design made for the XT-ADS phase of the EUROTRANS project. For the injector part, new design strategies and approaches, e.g. half resonant frequency, half transition-energy between the RFQ and the CH-DTL, and using the 4-rod RFQ structure instead of the originally proposed 4-vane RFQ, have been conceived and studied to reach a more reliable CW operation at reduced costs. In this paper, the design and simulation results of the MAX injector are presented.

WEPS045

Feasibility Study of a High-gradient Linac for Hadrontherapy

ion, cyclotron, accelerating-gradient, cavity

2589

S. Verdú-Andrés, U. Amaldi, A. Degiovanni
TERA, Novara, Italy
A. Faus-Golfe, S. Verdú-Andrés
IFIC, Valencia, Spain
P.A. Posocco
CERN, Geneva, Switzerland

Funding: The research leading to this results has been funded by the Seventh Framework Program [FP7/2007-2013] under grant agreement number 215840-2.
Compact, reliable and little consuming accelerators are needed for tumor treatment with hadrons. As solution, TERA proposes CABOTO (CArbon BOoster for Therapy in Oncology), a linac which boosts the energy of carbon ions and H₂ molecules coming from a cyclotron. The linac, typically a Side-Coupled Linac (SCL), is divided into several modules. The beam energy can be varied in steps of about 15 MeV/u without using absorbers by acting on the power (amplitude and/or phase) that feeds the different modules of the linac. This work presents the structure design of a 5.7 GHz high repetition rate SCL for a cyclinac, that accelerates carbon ions from 150 up to 400 MeV/u in less than 25 meters. The beam dynamics for this linac and its particular energy selection system is also discussed for different beam energy outputs.

WEPS046

Longitudinal Beam Acceptance of J-PARC Drift Tube Linac

DTL, beam-losses, simulation, cavity

2592

T. Maruta
KEK/JAEA, Ibaraki-Ken, Japan
M. Ikegami
KEK, Ibaraki, Japan
A. Miura, G.H. Wei
JAEA/J-PARC, Tokai-mura, Japan
H. Sako
JAEA, Ibaraki-ken, Japan

The longitudinal acceptance of the J-PARC Drift Tube Linac (DTL) was measured by synchronous phase scan method. The IMPACT simulation indicated DTL longitudinal acceptance is shrinked if the DTL tank level reduced, but beam energy finally acheved at the Linac is almost same as the case of nominal tank level. We measured the acceptance and confirmed the simulation is correct.

WEPS047

Beamloss Study at J-PARC Linac by using Geant4 Simulation

beam-losses, simulation, scattering, radiation

2595

T. Maruta
JAEA/J-PARC, Tokai-mura, Japan

Beamloss is one of the key issue for intense hadron beam accelerators. Most of case, origin of beamloss is scattering process between beam particle and residual gas inside vacuum duct. In the case of J-PARC Linac, H⁻ ions emitted from an Ion source are accelerated up to 181 MeV, then the beam is transported to RCS. The H⁻ ion is the system comprised from a proton and two electrons. If the H⁻ ion is scattered with residual gas, these one or two electrons are escaped, then H⁻ becomes H0 or H⁺(proton). H0 or H⁺ is uncontrollable and finally it goes to beam duct. This process is based on physics process, and Geant4 is matched to this kind of simulation study. I programmed SDTL (50 MeV) to L3BT (181 MeV) section at J-PARC Linac by using Geant4 code. I also wrote H⁻ and H0 library which makes it possible for Geant4 to simulate them. I will show the simulation results.

WEPS048

Dependence of Beam Loss on Vacuum Pressure Level in J-PARC Linac

beam-losses, vacuum, ion, collimation

2598

G.H. Wei
KEK/JAEA, Ibaraki-Ken, Japan
K. Hirano, T. Maruta, A. Miura
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
K. Ikegami
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

In J-PARC linac, a 181-MeV negative hydrogen beam is supported to a succeeding 3-GeV synchrotron with normal operation power at 100-300 kW. During operation, a beam loss in the straight section of the beam transport line immediately after the linac exit is found. The residual radiation level reaches 0.3 mSv/h on the surface of the vacuum chamber several hours after the beam shutdown with the linac beam power of 12 kW. We suppose that the residual gas scattering of negative hydrogen ions generates neutral hydrogen atoms and they give rise to the beam loss by hitting the vacuum chamber wall. To confirm this speculation, the vacuum pressure level in the linac had been changed in order to find the dependence of the beam loss on it. After data analysis, we found the relationship between beam loss amplitude, which was attained from beam loss signal, and vacuum pressure was linear. Corresponding deduction and simulation has been down according to the residual gas components in linac chamber. In this paper, we present the experimental result and some simulations in this study.

WEPS049

Floor Deformation of J-PARC Linac after the Tohoku Earthquake in Japan

alignment, cavity, DTL, injection

2601

T. Morishita, H. Asano
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
M. Ikegami
KEK, Ibaraki, Japan

J-PARC linac has finalized its precise alignment at the end of summer 2006, and the beam provision to the Rapid Cycling Synchrotron has been started at Sept. 2007. Since then, the deformation of the accelerator tunnel is small enough to keep the soundness of the alignment accuracy. Therefore, the linac has been operated without realignment of the accelerator components for these four years. However, the alignment has seriously been damaged due to the large earthquake at Mar. 11th, 2011 in eastern Japan. Now, work for restoration is being continued. In this paper, the deformation of the linac tunnel floor due to the earthquake is reported. Since then, aftershock happens frequently. We also report the stability of the tunnel floor.

WEPS051

Linac for the Compact Pulsed Hadron Source Project at Tsinghua University Beijing

proton, rfq, DTL, neutron

2607

X. Guan
TUB, Beijing, People's Republic of China

Funding: Work supported by the “985 Project” of the Ministry of Education of China, & Tsinghua University Independent Science and research Plan 20091081263.
A project of the Compact Pulsed Hadron Source (CPHS) led by the Department of Engineering Physics of Tsinghua University in Beijing, China has been reported in this paper. CPHS consists of a proton linac, a neutron target station (a Be target, moderators and reflector), and a small-angle neutron scattering instrument, a neutron imaging/radiology station, and a proton irradiation station. The accelerator part is composed of an ECR ion source. LEBT section, a RFQ accelerator, a DTL linac and a HEBT. An ECR ion source will give us a up to 60mA at 50keV proton beam with proton ration larger than 85%, and 0. 2 πmm mrad normalized emittance. A short LEBT will be used to matching the beam from ion source to the RFQ entrance. A 3 meters long RFQ machine can accelerate the proton to 3MeV. The Drift Tube Linac with permanent magnets focusing lens will accept the proton beam direct from RFQ. A 4.3 meters length of DTL with 43 cells will accelerate the beam up to 13MeV. The initial phase of the CPHS construction is scheduled to complete in the end of 2012.

WEPS052

Progress of Linear Injector for SSC at HIRFL

ion, simulation, DTL, rfq

2610

Y. He, X. Du, L.P. Sun, Z.J. Wang, C. Xiao, Y.Q. Yang, Y.J. Yuan, X.H. Zhang, Z.L. Zhang
IMP, Lanzhou, People's Republic of China
J.E. Chen, S.L. Gao, G. Liu, Y.R. Lu, K. Zhu
PKU/IHIP, Beijing, People's Republic of China
J. Wang
Lanzhou University of Technology, People's Republic of China

A heavy ion linear accelerator for Separate Sector Cyclotron (SSC) is constructing at Heavy Ion Research Facility at Lanzhou (HIRFL). It is a new injector for SSC to improve its output beam intensity of 2 times for Super Heavy Experiment (SHE) and 10 times for injection of Cooling Storage Ring (CSR) than old Cyclotron. It has a normal conducting linac at upstream of SSC and one superconducting cryomodule at downstream of SSC to shift beam energy. The designed current of the linac is 0.5 mA and output energy is 0.57 MeV/u and 1.02 MeV/u. Beam dynamic study and prototype fabrication are introduced in the paper.

WEPS053

The Conceptual Design of One of Injector II of ADS in China

rfq, solenoid, simulation, proton

2613

Y. He, H. Jia, C. Li, Y. Liu, Z.J. Wang, C. Xiao, Y. Yang, B. Zhang, H.W. Zhao
IMP, Lanzhou, People's Republic of China

A 10mA / 50 MeV superconducting proton linac as the demo of an ADS driver is designing and constructing in China. One of 10 MeV segments and corresponding prototypes are designed and fabricating at Institute of Modern Physics of the Chinese Academy of Sciences. It consists of 2.5 MeV RFQ and superconducting structure from 2.5 to 10 MeV. The conceptual design and development of prototype are introduced in the paper.

WEPS054

The Comparison of ADS Injector II with HWR Cavity and CH Cavity

cavity, proton, emittance, simulation

2616

Z.J. Wang, Y. He
IMP, Lanzhou, People's Republic of China

High current superconducting proton linac is being studied for Accelerator-driven System (ADS) Project hold by the Chinese Academic of Sciences (CAS). The injector II, which will accelerate proton beam from 2.1 MeV to 10 MeV, will be operated with superconducting cavity. At low energy part, there are two alternative choose, one is HWR cavity, the other is CH cavity. In this paper, the comparison of design with the two type cavities will be presented in view of beam dynamics.

WEPS055

Beam Commissioning Plan of PEFP 100-MeV linac

DTL, proton, rfq, site

2619

J.-H. Jang, Y.-S. Cho, H.-J. Kwon
KAERI, Daejon, Republic of Korea

Funding: This work was supported by Ministry of Education, Science and Technology of the Korean Government.
Proton engineering frontier project (PEFP) is developing a 100-MeV proton linear accelerator. It is scheduled to install the linac at Kyeungju site from the end of 2011. The linear accelerator consists of a 50-keV injector, a 3-MeV radio-frequency quadrupole (RFQ), and a 100-MeV drift tube linac (DTL). An important characteristic of this accelerator is extracting 20-MeV proton beams just after four DTL tanks. In this region, a medium energy beam transport (MEBT) will be installed for matching the proton beam to the following accelerator and extracting proton beams. The 100-MeV proton beams will be supplied to the users through another beam line which is located after the linac. This work summarized the beam commissioning plan of the proton linear accelerator.

WEPS057

Beam Dynamics Simulation in DTL with RF Quadrupole Focusing

quadrupole, focusing, lattice, DTL

2625

S.M. Polozov, A.S. Plastun
MEPhI, Moscow, Russia

There are a number of ion linear accelerators using RF focusing. Radio Frequency Quadrupole (RFQ) is the most useful RF linac in low energy range. Using of RFQ for medium energies is impractical because of low energy gain rate. Therefore, proposed to combine Drift Tube Linac (DTL), keeping tolerable energy gain rate, and RFQ. Such linac consists of periodic sequence of a several number of drift tubes and RF quadrupole electrodes, located in the same IH resonator. Different variants of the structure will be considered. Beam dynamics simulation will be carried out through these variants. Main parameters of the linac will be determine. The RF model design, providing combination of DTL and RFQ, will be proposed.

WEPS059

Layout of the ESS Linac

cryomodule, cavity, proton, rfq

2631

H. Danared, M. Eshraqi, W. Hees, A. Jansson, M. Lindroos, S. Peggs, A. Ponton
ESS, Lund, Sweden

The European Spallation Source will use a 2.5 GeV, 50 mA pulsed proton linac to produce an average 5 MW of power on the spallation target. It will consist of normal-conducting part accelerating particles to 50 MeV in an RFQ and a drift-tube linac and a superconducting part with spoke resonators and two families of elliptical cavities. A high-energy beam transport takes the particles through an upgrade section and at least one bend and demagnifies the beam on to the target. The paper will present the current layout of the linac and discuss parameters that define its length from source to target.

WEPS060

Design and Optimization of ESS LINAC

cavity, quadrupole, proton, cryomodule

2634

M. Eshraqi
ESS, Lund, Sweden

The {\sc linac} of the European Spallation Source will accelerate the proton beam to its final energy mainly by using superconducting structures. Therefore choosing the right transition energy between these superconducting structures as well as choosing the cavity length and number of cells which enhances the acceleration is of great importance. Two types of {\sc linac}s will be studied, a {\sc linac} with superconducting quadrupoles and a {\sc linac} with normal conducting, resistive, quadrupoles. The procedure to find the optimized {\sc linac} will be described here.

WEPS061

ESS LINAC, Design and Beam Dynamics

cavity, emittance, quadrupole, proton

2637

M. Eshraqi, H. Danared
ESS, Lund, Sweden

The European Spallation Source, {\sc ESS}, will use a linear accelerator delivering a high intensity proton beam with an average beam power of 5~MW to the target station at 2.5~GeV in long pulses of 2~msec. The ESS {\sc Linac} will use two types of superconducting cavities, spoke resonators at low energy and elliptical cavities at high energies. The possibilities to upgrade to a higher power {\sc Linac} at fixed energy are considered. This paper will present a review of the superconducting {\sc Linac} design and the beam dynamics studies.

WEPS062

Design and Beam Dynamics Study of Hybrid ESS LINAC

cavity, cryomodule, accelerating-gradient, proton

2640

M. Eshraqi, H. Danared, W. Hees, A. Jansson
ESS, Lund, Sweden

The European Spallation Source, {\sc ESS}, will use a superconducting linear accelerator delivering high current long pulses with an average beam power of 5~MW to the target station at 2.5~GeV. A new cryomodule architecture is proposed which allows for a transition between cryomodules in the sub-100~K region, this region can work even at room temperature. This new hybrid design will generate a lower heat load with respect to a fully segmented design - while still providing easy access to individual cryomodules for maintenance and repair. This paper will present a review of the {\sc linac} design, beam dynamics studies and a preliminary cryogenic analysis of the transition region.

WEPS063

Compersation of Effect of Malfunctioning Spoke Resonators on Ess Beam Quality

cavity, quadrupole, DTL, proton

2643

M. Eshraqi
ESS, Lund, Sweden

The {\sc linac} of the European Spallation Source will accelerate the proton beam to 2.5~GeV, 98\% of this energy is gained using superconducting structures. The superconducting {\sc linac} is composed of two types of cavities, double spoke resonators and five-cell elliptical cavities. The {\sc linac}, which is five times more powerful than the most powerful existing {\sc linac}, and the spoke cavities that have never been used at such a scale make it necessary to study the effect of one or a few spoke resonators not functioning properly and to find a solution where the defect is compensated by retuning of the neighbouring cavities.

WEPS064

Upgrade Strategies for High Power Proton Linacs

cavity, target, neutron, proton

2646

M. Lindroos, H. Danared, M. Eshraqi, D.P. McGinnis, S. Molloy, S. Peggs, K. Rathsman
ESS, Lund, Sweden
R.D. Duperrier
CEA/DSM/IRFU, France
J. Galambos
ORNL, Oak Ridge, Tennessee, USA

High power proton linacs are used as drivers for spallation neutron sources, and are proposed as drivers for sub-critical accelerator driven thorium reactors. A linac optimized for a specific average pulse current can be difficult, or inefficient, to operate at higher currents, for example due to mis-matching between the RF coupler and the beam loaded cavity, and due to Higher Order Mode effects. Hardware is in general designed to meet specific engineering values, such as pulse length and repetition rate, that can be costly and difficult to change, for example due to pre-existing space constraints. We review the different upgrade strategies that are available to proton driver designers, both for linacs under design, such as the European Spallation Source (ESS) in Lund, and also for existing linacs, such as the Spallation Neutron Source (SNS) in Oak Ridge. Potential ESS upgrades towards a beam power higher than 5 MW preserve the original time structure, while the SNS upgrade is directed towards the addition of a second target station.

WEPS065

Segmentation in the Project-X Low Energy CW Linac Front End

cavity, focusing, solenoid, lattice

2649

J.-F. Ostiguy, B.G. Shteynas, N. Solyak
Fermilab, Batavia, USA

Funding: Fermi National Accelerator Laboratory (Fermilab) is operated by Fermi Research Alliance, LLC. for the U.S. Department of Energy under contract DE-AC02-07CH11359
The low-energy front-end of the Project-X 2.5 MeV - 3 GeV linac utilizes superconducting single-spoke resonators for acceleration and solenoids for transverse focusing. To take advantage of the available accelerating field in the cavities, it is necessary to minimize the period length. This leads to a compact arrangement of cavities and solenoids with very minimal open longitudinal space. While beam position monitors and correctors can be integrated to the solenoid assemblies inside a cryostat, some instrumentation such as beam profile monitors require dedicated warm longitudinal space. In this paper we discuss an arrangement where the front-end is segmented in crystats comprising about half a dozen lattice periods separated by a minimal amount of warm longitudinal space. We discuss the impact of introducting such openings and present an optical solution integrating them. The strategy and constraints leading to this solution are outlined.

WEPS066

Residual Focusing Asymmetry in Superconducting Spoke Cavities

focusing, cavity, solenoid, lattice

2652

J.-F. Ostiguy, N. Solyak
Fermilab, Batavia, USA

Funding: Fermi National Accelerator Laboratory (Fermilab) is operated by Fermi Research Alliance, LLC. for the U.S. Department of Energy under contract DE-AC02-07CH11359.
Project-X is a proposed high intensity proton source at Fermilab. Protons (H⁻) are first accelerated from 2.5 to 3 GeV in a superconducting linac operating in CW mode. While most of the particles are delivered to a variety of precision experiments, a fraction ( about 10%) is further accelerated to 8 GeV in a second superconducting linac operating in pulsed mode. In the low energy front-end of the first stage CW linac, single-spoke cavities are used for acceleration while solenoids and quadrupole doublets provide transverse focusing. The transverse rf defocusing arising from the spoke cavities has a small residual asymmetry whose effect can become noticeable in periods where the transverse phase advance is low. In this paper we discuss this effect, its practical consequences, as well as possible mitigation strategies.

WEPS067

An H-Mode Accelerator with PMQ Focusing as a LANSCE DTL Replacement

DTL, cavity, focusing, proton

2655

S.S. Kurennoy, L. Rybarcyk, T.P. Wangler
LANL, Los Alamos, New Mexico, USA

High-efficiency normal-conducting RF accelerating structures based on H-mode cavities with a transverse beam focusing by permanent-magnet quadrupoles (PMQ) have been developed for beam velocities in the range of a few percent of the speed of light*. At these low beam velocities, an inter-digital H-mode (IH-PMQ) linac is an order of magnitude more efficient than a standard drift-tube linac (DTL). At the Los Alamos Neutron Science Center (LANSCE), upgrades of the proton linac front end are currently under consideration. In view of these plans, we explore a further option of replacing the aging LANSCE DTL by an efficient H-PMQ accelerator. Here we assume that a 201.25-MHz RFQ-based front end up to 750 keV (4% of the speed of light) is followed first by IH-PMQ structures and then by cross-bar H-mode cavities with PMQ focusing (CH-PMQ). Such an H-PMQ linac would bring proton and H⁻ beams to the energy of 100 MeV and transfer them into the existing side-coupled-cavity linac (CCL). Results of the combined electromagnetic and beam-dynamics modeling of the proposed H-PMQ accelerator will be presented.
* S.S. Kurennoy et al., “H-Mode Accelerating Structures with PMQ Beam Focusing,” PRST-AB, 2011 (submitted).

WEPS068

Progress towards an RFQ-based Front End for LANSCE

rfq, beam-transport, neutron, proton

2658

R.W. Garnett, S.S. Kurennoy, J.F. O'Hara, L. Rybarcyk
LANL, Los Alamos, New Mexico, USA
A. Schempp
IAP, Frankfurt am Main, Germany

Funding: This work is supported by the U. S. Department of Energy Contract DE-AC52-06NA25396.
The LANSCE linear accelerator at Los Alamos National Laboratory provides H⁻ and H⁺ beams to several user facilities that support Isotope Production, NNSA Stockpile Stewardship, and Basic Energy Science programs. These beams are initially accelerated to 750 keV using Cockcroft-Walton (CW) based injectors that have been in operation for over 37 years. They have failure modes which can result in prolonged operational downtime due to the unavailability of replacement parts. To reduce long-term operational risks and to realize future beam performance goals in support of the Materials Test Station (MTS) and the Matter-Radiation Interactions in Extremes (MaRIE) Facility, plans are underway to develop a Radio-Frequency Quadrupole (RFQ) based front end as a modern injector replacement for the existing CW injectors. Our progress to date will be discussed.

WEPS074

H⁻ Injection Studies of FFAG Accelerator at KURRI

injection, beam-transport, proton, neutron

2676

K. Okabe, Y. Niwa, I. Sakai
University of Fukui, Faculty of Engineering, Fukui, Japan
Y. Ishi, Y. Kuriyama, J.-B. Lagrange, Y. Mori, R. Nakano, B. Qin, T. Uesugi, E. Yamakawa
KURRI, Osaka, Japan

Aiming to demonstrate the basic feasibility of the accelerator driven sub-critical reactor (ADSR), proton Fixed Field Alternating Gradient (FFAG) accelerator complex as a neutron production driver has been constructed in Kyoto University Research Reactor Institute (KURRI). In order to upgrade beam power of the FFAG neutron source, a project about a new H⁻ linac injector for FFAG main ring instead of present injector has been started. A charge exchange multi-turn beam injection has been performed for the first time at FFAG main ring in KURRI. In this paper, the detail of injection system and beam study of low energy H⁻ injection at FFAG is described.

WEPS076

Straight Scaling FFAG

emittance, vacuum, closed-orbit, instrumentation

2682

J.-B. Lagrange, Y. Ishi, Y. Kuriyama, Y. Mori, T. Planche, B. Qin, T. Uesugi, E. Yamakawa
KURRI, Osaka, Japan
K. Okabe
University of Fukui, Faculty of Engineering, Fukui, Japan
A. Sardet, R. Wasef
LPSC, Grenoble Cedex, France

Recent developments in scaling fixed field alternating gradient (FFAG) accelerators have opened new ways for lattice design, with straight sections, and insertions like dispersion suppressors. An experiment to study straight sections and dispersion suppressors is under progress at KURRI.

WEPS077

Present Status of FFAG Proton Accelerator at KURRI*

proton, neutron, ion, controls

2685

Y. Mori, Y. Ishi, Y. Kuriyama, J.-B. Lagrange, R. Nakano, T. Planche, T. Uesugi, E. Yamakawa
KURRI, Osaka, Japan
Y. Niwa, K. Okabe, I. Sakai
University of Fukui, Faculty of Engineering, Fukui, Japan

The 150MeV FFAG proton accelerator has been developed at Kyoto University Research Reactor Institute(KURRI) for the fundamental study of Accelerator Driven Sub-crittical Reactor (ADSR). Recently, a new H⁻ injector was constructed to improve the beam quality and intensity. The paper will describe the detail of the preset status of FFAG proton accelerator at KURRI.

WEPS078

Compact FFAG Accelerators for Medium Energy Hadron Applications

proton, hadron, extraction, injection

2688

B. Qin, Y. Ishi, Y. Kuriyama, J.-B. Lagrange, Y. Mori, K. Okabe, T. Uesugi, E. Yamakawa
KURRI, Osaka, Japan

Funding: This work was supported by Japan Science and Technology Agency under Strategic Promotion of Innovative Research and Development Program.
Medium energy hadron beams are widely applied in accelerator driven subcritical systems (ADSR), high intensity neutron sources and carbon therapy. Compactness feature is important for this energy region, especially in the case of medical use purposes. This paper introduces a novel superferric scheme with scaling fixed-field alternating gradient (FFAG) accelerators, which can deliver 400MeV/u carbon ions or 1.2GeV protons. By using high permeability materials, 5T magnetic field with high field index can be achieved to reduce accelerator circumference significantly. The lattice configuration and design of superferric magnet are described in details.

WEPS090

The Myrrha Linear Accelerator

cavity, rfq, cryomodule, proton

2718

D. Vandeplassche
SCK-CEN, Mol, Belgium
J.-L. Biarrotte
IPN, Orsay, France
H. Klein, H. Podlech
IAP, Frankfurt am Main, Germany

Funding: European Atomic Energy Community's (EURATOM) Seventh Framework Programme FP7/2007-2011, grant agreement no. 269565 (MAX project)
Accelerator Driven Systems (ADS) are promising tools for the efficient transmutation of nuclear waste products in dedicated industrial installations, called transmuters. The Myrrha project at Mol, Belgium, placed itself on the path towards these applications with a multipurpose and versatile system based on a liquid PbBi (LBE) cooled fast reactor (80 MWth) which may be operated in both critical and subcritical modes. In the latter case the core is fed by spallation neutrons obtained from a 600 MeV proton beam hitting the LBE coolant/target. The accelerator providing this beam is a high intensity CW superconducting linac which is laid out for the highest achievable reliability. The combination of a parallel redundant and of a fault tolerant scheme should allow obtaining an MTBF value in excess of 250 hours that is required for optimal integrity and successful operation of the ADS. Myrrha is expected to be operational in 2023. The forthcoming 4-year period is fully dedicated to R&D activities, and in the field of the accelerator they are strongly focused on the reliability aspects and on the proper shaping of the beam trip spectrum.

WEPS092

High Energy Beam Line Design of the 600MeV, 4 mA Proton Linac for the MYRRHA Facility

target, vacuum, dipole, proton

2721

H. Saugnac
IPN, Orsay, France

The general goal of the CDT project is to design a FAst Spectrum Transmutation Experimental Facility (FASTEF) able to demonstrate efficient transmutation and associated technology through a system working in subcritical and/or critical mode. A superconducting LINAC, part of the MYRRHA facility, will produce a 600 MeV, 4 mA proton beam and transport it to the spalation target located inside the reactor core. On this paper we focus on the final beam line design and describe optic simulations, beam instrumentation, integration inside the reactor building, mechanical and vacuum aspects as well as a preliminary design of the 2.4 MW beam dump located at the end of the accelerator tunnel.

WEPS095

Status of J-PARC Accelerator Facilities after the Great East Japan Earthquake

status, vacuum, DTL, neutron

2727

K. Hasegawa, M. Kinsho, H. Oguri
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
T. Koseki
KEK, Tokai, Ibaraki, Japan

J-PARC was heavily affected by the March 11 Great East Japan Earthquake. When the earthquake struck, we had a beam study operation of the linac and the machine immediately stopped. Fortunately, we had no effects of tsunami that happened nearby and no one was injured. We can see subsidence at many places; about 1.5m over the wide area at the entrance of the linac building, about 50cm over the area of 1m x 10m at the main ring building, etc. Underground water is coming into the linac and the main ring tunnels. The water level at the linac reached a depth of 10 cm, but pumping with a diesel generator successfully saved from further flooding. At the RCS, the circulating road went wavy and the yard area for electricity and water devices was heavily distorted. Therefore, a high voltage power is not available on the date of abstract submission. We are investigating damages of each facility and also we are trying to estimate the beam restoration. The current status of the J-PARC accelerator facilities after the earthquake will be presented.

WEPS100

Status of 100-MeV Proton Linac Development for PEFP

site, proton, DTL, alignment

2742

Y.-S. Cho, S. Cha, I.-S. Hong, J.-H. Jang, D.I. Kim, H.S. Kim, H.-J. Kwon, K. Min, B.-S. Park, J.Y. Ryu, K.T. Seol, Y.-G. Song, S.P. Yun
KAERI, Daejon, Republic of Korea
J.S. Hong
KAPRA, Cheorwon, Republic of Korea

Funding: This wok was supported through the Proton Engineering Frontier Project by the Ministry of Education, Science and Technology of Korea.
The Proton Engineering Frontier Project (PEFP) is developing a 100-MeV high-duty-factor proton linac, which consists of a 50-keV microwave ion source, a 3-MeV radio frequency quadrupole, a 100-MeV drift tube linac, a 20-MeV beam transport line, and a 100-MeV beam transport line. It will supply proton beams of 20-MeV and 100-MeV with peak current of 20 mA to users for proton beam applications. The beam duty factor will be 24% and 8% respectively. The 20-MeV front-end accelerator has been installed and operated at the KAERI Daejeon test stand for user service, and the rest part of the accelerator has been fabricated and will be installed at the new site of Gyeongju City in 2011. The detailed status of the 100-MeV proton linac will be presented.

WEPS102

Latest News on the Beam Dynamics Design of SPL

cavity, emittance, quadrupole, lattice

2748

P.A. Posocco, M. Eshraqi, A.M. Lombardi
CERN, Geneva, Switzerland

SPL is a superconducting H− LINAC under study at CERN. The SPL is designed to accelerate the 160 MeV beam of LINAC4 to 5 GeV, and is composed of two fami¬lies of 704.4 MHz elliptical cavities with geometrical betas of 0.65 and 1.0. Two families of cryo-modules are considered: the low-beta cryo-module houses 3 low-beta cavities, whereas the high-beta one houses 8 cavities. The transverse focusing is performed with normal-conducting quadrupoles arranged in 2 different lattices: FD0 at lower and F0D0 at higher energies. The regular lattices are in-terrupted at the transition between low beta and high beta cryo-modules and for extracting medium energy beams at 1.4 and 2.5 GeV, where the change of the transverse lattice is performed. In this paper the latest beam dynamics studies will be presented together with the sensitivity of the SPL performance to RF errors, alignment tolerances and quadrupole high order components.

WEPS105

A Common Proton Driver for a Neutrino Factory and a Spallation Neutron Source Based on Megawatt Upgrades to ISIS

proton, neutron, injection, booster

2757

J.W.G. Thomason
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
J. Pasternak
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

The Rutherford Appleton Laboratory (RAL) is home to ISIS, the world’s most productive spallation neutron source. Potential upgrades of the ISIS accelerators to provide beam powers of 2 – 5 MW in the few GeV energy range could be envisaged as the starting point for a proton driver shared between a short pulse spallation neutron source and the Neutrino Factory. The concept of sharing a proton driver between other facilities and the Neutrino Factory is an attractive, cost-effective solution which is already being studied in site-specific cases at CERN and FNAL. Although in the RAL case the requirements for the Neutrino Factory baseline proton energy and time structure are different from those for a spallation neutron source, an additional RCS or FFAG booster bridging the gap in proton energy and performing appropriate bunch compression seems feasible.

WEPS106

Status of Injection Upgrade Studies for the ISIS Synchrotron

injection, space-charge, simulation, synchrotron

2760

C.M. Warsop, D.J. Adams, D.J.S. Findlay, I.S.K. Gardner, S.J.S. Jago, B. Jones, R.J. Mathieson, S.J. Payne, B.G. Pine, A. Seville, H. V. Smith, J.W.G. Thomason, R.E. Williamson
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
J. Pasternak
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
C.R. Prior, G.H. Rees
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

ISIS is the spallation neutron source at the Rutherford Appleton Laboratory in the UK. Operation centres on a high intensity proton accelerator, consisting of a 70 MeV linac and an 800 MeV rapid cycling synchrotron, which provides a beam power of 0.2 MW. Obsolescence issues are motivating plans to replace the ageing 70 MeV linac, and this paper summarises the status of studies looking at how a new, higher energy linac (~180 MeV) could be used to increase beam power in the existing synchrotron. Reduced space charge and optimized injection might allow beam powers in the 0.5 MW regime, thus providing a very cost effective upgrade. The key areas of study are: design of a practical injection straight and magnets; injection painting and dynamics; foil specifications; acceleration dynamics; transverse space charge; instabilities; RF beam loading; beam loss and activation; diagnostics and possible damping systems. Results from work on most of these topics suggest that beam powers of ~0.5 MW may well be possible, but a number of topics, particularly transverse stability, still look challenging. Conclusions so far are presented, as is progress on R&D on the main intensity limiting issues.

WEPZ014

Upgrade of the Argonne Wakefield Accelerator Facility (AWA): Commissioning of the RF Gun and Linac Structures for Drive Beam Generation

wakefield, gun, electron, acceleration

2799

M.E. Conde, D.S. Doran, W. Gai, R. Konecny, W. Liu, J.G. Power, Z.M. Yusof
ANL, Argonne, USA
S.P. Antipov, C.-J. Jing
Euclid TechLabs, LLC, Solon, Ohio, USA
E.E. Wisniewski
Illinois Institute of Technology, Chicago, Illinois, USA

Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC02-06CH11357.
Research at the AWA Facility has been focused on the development of electron beam driven wakefield structures. Accelerating gradients of up to 100 MV/m have been excited in dielectric loaded cylindrical structures operating in the microwave range of frequencies. Several upgrades, presently underway, will enable the facility to explore higher accelerating gradients, and also be able to generate longer RF pulses of higher intensity. The major items included in the upgrade are: (a) a new RF gun with a higher quantum efficiency photocathode will replace the RF gun that has been used to generate the drive bunches; (b) the existing RF gun will be used to generate a witness beam to probe the wakefields; (c) three new L-band RF power stations, each providing 25 MW, will be added to the facility; (d) five linac structures will be added to the drive beamline, bringing the beam energy up from 15 MeV to 75 MeV. The upgraded drive beam will consist of bunch trains of up to 32 bunches spaced by 0.77 ns with up to 100 nC per bunch. The goal of future experiments is to reach accelerating gradients of several hundred MV/m and to extract RF pulses with GW power level.

WEPZ016

Generation and Characterization of Electron Bunches with Ramped Current Profiles at the FLASH Facility

electron, laser, wakefield, free-electron-laser

2805

P. Piot
Fermilab, Batavia, USA
C. Behrens, C. Gerth, M. Vogt
DESY, Hamburg, Germany
F. Lemery, D. Mihalcea
Northern Illinois University, DeKalb, Illinois, USA

Funding: This work was supported the Defense Threat Reduction Agency, Basic Research Award # HDTRA1-10^-1-0051, to Northern Illinois University and the German's Bundesministerium f\"ur Bildung und Forschung
We report on the successful generation of electron bunches with current profiles that have a quasi-linear dependency on the longitudinal coordinate. The technique relies on impressing nonlinear correlations in the longitudinal phase space using a linac operating at two frequencies (1.3 and 3.9 GHz) and a bunch compressor. Data taken for various accelerator settings demonstrate the versatility of the method. The produced bunches have parameters well matched to drive high-gradient accelerating field with enhanced transformer ratio in beam-driven accelerators based on sub-mm-sizes dielectric or plasma structures.

WEPZ017

ESTB: A New Beam Test Facility at SLAC

electron, kicker, hadron, emittance

2808

M.T.F. Pivi, H. Fieguth, C. Hast, R.H. Iverson, J. Jaros, R.K. Jobe, L. Keller, T.V.M. Maruyama, D.R. Walz, M. Woods
SLAC, Menlo Park, California, USA

Funding: Work supported by the Director, Office of Science, High Energy Physics, U.S. DOE under Contract No. DE-AC02-76SF00515.
End Station A Test Beam (ESTB) is a beam line at SLAC using a small fraction of the bunches of the 13.6 GeV electron beam from the Linac Coherent Light Source (LCLS), restoring test beam capabilities in the large End Station A (ESA) experimental hall. ESTB will provide one of a kind test beam essential for developing accelerator instrumentation and accelerator R&D, performing particle and particle astrophysics detector research, linear collider machine and detector interface (MDI) R&D studies, development of radiation-hard detectors, and material damage studies with several distinctive features. In the past, 18 institutions participated in the ESA program at SLAC. In stage I, 4 new kicker magnets will be added to divert 5 Hz of the LCLS beam to ESA. A new beam dump is installed and a new Personnel Protection System (PPS) is built in ESA. In stage II, we plan to install a secondary hadron target, able to produce pions up to about 12 GeV/c at 1 particle/pulse. We report about the ESTB commissioning, status and plan for tests.

THYA01

Beam Dynamics in Positron Injector Systems for Next Generation B Factories

emittance, positron, injection, target

2857

N. Iida, H. Ikeda, T. Kamitani, M. Kikuchi, K. Oide, D.M. Zhou
KEK, Ibaraki, Japan

SuperKEKB, the upgrade plan of KEKB, aims to boost the luminosity up to 8x10³5 /cm²/s. The beam energy of the Low Energy Ring (LER) is 4 GeV for positrons, and that of the High Energy Ring is 7 GeV for electrons. SuperKEKB is designed to produce low emittance beams. The horizontal and vertical emittances of the injection beams are 12.5 nm and 0.9 nm, respectively, which are one or two orders smaller than those of KEKB. The normal and maximum required charges are 4 nC and 8nC, respectively. The positron injector system consists of the source, capture systems, L-band and S-band linacs, collimators, an energy compression system (ECS), a 1.1-GeV damping ring, a bunch compression system (BCS), S-band and C-band linacs, another ECS and a beam transport line into the LER. For the low emittance beam with a huge amount of the positron charge like 8nC, some kinds of issues by the instabilities will be predicted due to such as Coherent Synchrotron Radiation (CSR), beam loading, beam-beam effects, and so on. This paper reports a design of the positron beam injection system for SuperKEKB. In addition, comparisons with SuperB are described.

Slides THYA01 [7.572 MB]

THOAB01

Accelerator-driven Subcritical Molten-salt-fueled Reactors

neutron, radiation, target, proton

2868

R.P. Johnson
Muons, Inc, Batavia, USA
C. Bowman
ADNA, Los Alamos, New Mexico, USA

Reactors built using solid fissile materials sealed in fuel rods have an inherent safety problem in that volatile radioactive materials in the rods are accumulated and can be released in dangerous amounts. Accelerator parameters for subcritical reactors that have been considered in recent studies have primarily been based on using solid nuclear fuel much like that used in all operating critical reactors as well as the thorium-burning accelerator-driven energy amplifier proposed by Rubbia et al. An attractive alternative reactor design that used molten salts was experimentally studied at ORNL in the 1960s, where a critical molten salt reactor was successfully operated using enriched U235 or U233 tetrafluoride fuels. These experiments give confidence that an accelerator-driven subcritical molten salt reactor will work as well or better than conventional reactors, having better efficiency due to their higher operating temperature, having the inherent safety of subcritical operation, and having constant purging of volatile radioactive elements to eliminate their accumulation and potential accidental release in dangerous amounts.

Slides THOAB01 [5.723 MB]

THYB01

Advanced Beam Manipulation Techniques at SPARC

gun, emittance, simulation, laser

2877

A. Mostacci, D. Alesini, P. Antici, A. Bacci, M. Bellaveglia, R. Boni, M. Castellano, E. Chiadroni, G. Di Pirro, A. Drago, M. Ferrario, A. Gallo, G. Gatti, A. Ghigo, E. Pace, A.R. Rossi, B. Spataro, C. Vaccarezza
INFN/LNF, Frascati (Roma), Italy
A. Cianchi
Università di Roma II Tor Vergata, Roma, Italy
B. Marchetti
INFN-Roma II, Roma, Italy
M. Migliorati
University of Rome "La Sapienza", Rome, Italy
L. Palumbo
Rome University La Sapienza, Roma, Italy
V. Petrillo, L. Serafini
Istituto Nazionale di Fisica Nucleare, Milano, Italy
C. Ronsivalle
ENEA C.R. Frascati, Frascati (Roma), Italy

SPARC in Frascati is a high brightness photo-injector used to drive Free Electron Laser experiments and explore advanced beam manipulation techniques. The R&D effort made for the optimization of the beam parameters will be presented here, together with the major experimental results achieved. In particular, we will focus on the generation of sub-picosecond, high brightness electron bunch trains via velocity bunching technique (the so called comb beam). Such bunch trains can be used to drive tunable and narrow band THz sources, FELs and plasma wake field accelerators.

Slides THYB01 [20.772 MB]

THOBB01

Evaluation of Performance, Reliability, and Risk for High Peak Power RF Sources from S-band through X-band for Advanced Accelerator Applications

klystron, high-voltage, focusing, electron

2882

M.V. Fazio, C. Adolphsen, A. Jensen, C. Pearson, D.W. Sprehn, A.E. Vlieks, F. Wang
SLAC, Menlo Park, California, USA
M.V. Fazio
LANL, Los Alamos, New Mexico, USA

Historically linear accelerator development and the choice of frequency have been driven by the availability of RF power sources. This is also true at the present time and is particularly significant as new accelerators are being conceived and planned over a wide frequency range for FEL light sources and other applications. This paper evaluates the current state of the technology for high peak power RF sources from S-band through X-band including reliability and the facility risk incurred for applications demanding high availability and decades-long operation.

Slides THOBB01 [2.326 MB]

THPC030

Design of a BeamTransport Line from the SACLA Linac to the SPring-8 Storage Ring

lattice, emittance, beam-transport, storage-ring

2975

K. Tsumaki, K. Fukami, T. Watanabe
JASRI/SPring-8, Hyogo-ken, Japan
S. Itakura, N. Kumagai
RIKEN/SPring-8, Hyogo, Japan

The SPring-8 Angstrom Compact Free Electron Laser (SACLA) linac has high beam qualities. The normalized emittance is less than 1 mm.mrad and the bunch length is less than 100 fs. If this high quality beam is injected to the SPring-8 storage ring, many interesting experiments can be done. On the other hand, the upgrade of the SPring-8 storage ring is under contemplation. The dynamic aperture of the new storage ring is expected to be so small that the small emittance beam is required to keep high beam injection efficiency. The SACLA linac beam also fulfills this requirement. For these reasons, it was decided to connect the SACLA linac and the SPring-8 storage ring. Since there is already an injection transport line from the SPring-8 synchrotron to the storage ring, the new transport line from the linac to this transport line has been constructed*. We designed the three types of magnet lattice for the new transport line; FODO, Double Bend Achromat and Triple Bend Achromat lattice. Emittance growth and bunch lengthening are calculated for each lattice and the beam qualities are compared. In this paper, lattice design and the comparison of the beam quality for each lattice are described.
* C. Mitsuda et al., this conference.

THPC037

Accelerators of the Central Japan Synchrotron Radiation Facility Project (II)

storage-ring, synchrotron, booster, electron

2987

N. Yamamoto, M. Hosaka, A. Mano, H. Morimoto, K. Takami, Y. Takashima
Nagoya University, Nagoya, Japan
Y. Hori
KEK, Ibaraki, Japan
M. Katoh
UVSOR, Okazaki, Japan
S. Koda
SAGA, Tosu, Japan
S. Sasaki
JASRI/SPring-8, Hyogo-ken, Japan

Central Japan Synchrotron Radiation (SR) Facility Project is making progress for the service from FY2012. The construction of SR building is almost completed in the Aichi area of Japan, and the installs of accelerators will start in a few week. The key equipments of our accelerators are an 1.2 GeV compact electron storage ring that is able to supply hard X-rays and a full energy injector for top-up operation. The beam current and natural emittance of the storage ring are 300 mA and 53 nmrad. The circumference is 72 m. The magnetic lattice consists of four triple bend cells and four straight sections. The bending magnets at the centers of the cells are 5 T superconducting magnets and the critical energy of the SR is 4.8 keV. The injector consists of a 50 MeV linac and a booster synchrotron with the circumference of 48 m. To save construction expenses, the injector is built at inside of the storage ring. More than ten hard X-ray beam-line can be constructed. One variable polarization undulator will be installed in the first phase. The top-up operation will be introduced as early as possible.

THPC042

Status and Development of the SAGA Light Source

storage-ring, laser, controls, undulator

2996

T. Kaneyasu, Y. Iwasaki, S. Koda, Y. Takabayashi
SAGA, Tosu, Japan

The SAGA Light Source (SAGA-LS) is a synchrotron radiation facility consisting of a 255 MeV injector linac and a 1.4 GeV storage ring, and has been stably providing synchrotron light since 2006. The annual failure time is less than 1% of the user time in the recent two years. Three insertion devices are installed in the storage ring: an APPLE-II undulator, a planar type undulator (Saga Univ.) and a 4 T superconducting wiggler (SCW). The SCW contains a hybrid three-pole magnet; the main pole of the magnet is surrounded by superconducting coils while side poles are normal conducting magnets. The main pole of the SCW is cooled by a GM cryocooler, which allows the SCW be operated without liquid helium. Since the installation in March 2010, the SCW has been operated stably. To control the ID parameters during the user time, a feed-forward correction system which minimizes the ID effects on the emittance coupling was developed. The laser Compton Gamma-rays were generated by using a CO2 laser and were used for beam energy measurement. In addition, research works on the beam lifetime and interaction between electron beam and crystal, and development of a multipole magnet are in progress.

THPC053

Shanghai Soft X-Ray Free Electron Laser Test Facility

laser, radiation, FEL, electron

3011

Z.T. Zhao
SINAP, Shanghai, People's Republic of China

As a critical development step towards constructing a hard X-ray FEL in China, a soft X-ray FEL test facility (SXFEL) was proposed and will be constructed at the SSRF campus by a joint team of Institute of Tsinghua University and Shanghai Institute of Applied Physics. This test facility, based on an 840MeV electron linear accelerator, aims at generating 9nm FEL radiation with two-stage cascaded HGHG scheme. The project proposal was approved in February 2011 by central government, and the constrction is expected to start in early 2012. This paper describes the preliminary design of this soft X-ray test facility and the R&D progress of the key FEL technologies in the SDUV-FEL test bench.

THPC054

Project Status of the Polish Synchrotron Radiation Facility Solaris

storage-ring, synchrotron, cavity, radiation

3014

C.J. Bocchetta, P.P. Goryl, K. Królas, M. Mlynarczyk, M.J. Stankiewicz, P.S. Tracz, Ł. Walczak, A.I. Wawrzyniak
Solaris, Krakow, Poland
J. Ahlbäck, Å. Andersson, M. Eriksson, M.A.G. Johansson, D. Kumbaro, S.C. Leemann, L. Malmgren, J.H. Modéer, P.F. Tavares, S. Thorin
MAX-lab, Lund, Sweden
E. Al-dmour, D. Einfeld
CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain

Funding: European Regional Development Fund within the frame of the Innovative Economy Operational Program: POIG.02.01.00-12-213/09
The Polish synchrotron radiation facility Solaris is being built at the Jagiellonian University in Krakow. The project is based on an identical copy of the 1.5 GeV storage ring being concurrently built for the MAX IV project in Lund, Sweden. A general description of the facility is given together with a status of activities. Unique features associated with Solaris are outlined, such as infra-structure, the injector and operational characteristics.

THPC057

Operation of the ALBA Injector

booster, emittance, injection, storage-ring

3023

M. Pont, U. Iriso, R. Muñoz Horta, F. Pérez
CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain

The ALBA injector made of a 100 MeV linac, operating at 110 MeV, and a full energy (3 GeV) booster synchrotron has been routinely in operation since October 2010. The stability of the linac and of the booster on reliability and performance is examined. Also results on the beam performance obtained with the installed diagnostic equipment will be discussed.

THPC058

The MAX IV Synchrotron Light Source

emittance, lattice, storage-ring, vacuum

3026

M. Eriksson, J. Ahlbäck, Å. Andersson, M.A.G. Johansson, D. Kumbaro, S.C. Leemann, F. Lindau, L.-J. Lindgren, L. Malmgren, J.H. Modéer, R. Nilsson, M. Sjöström, J. Tagger, P.F. Tavares, S. Thorin, E.J. Wallén, S. Werin
MAX-lab, Lund, Sweden
B. Anderberg
AMACC, Uppsala, Sweden
L.O. Dallin
CLS, Saskatoon, Saskatchewan, Canada

The MAX IV synchrotron radiation facility is currently being constructed in Lund, Sweden. It consists of a 3 GeV linac injector and 2 storage rings operated at 1.5 and 3 GeV respectively. The linac injector will also be used for the generation of short X-ray pulses. The three machines mentioned above will be descibed with some emphasis on the effort to create a very small emittance in the 3 GeV ring. Some unconventional technical solutions will also be presented.

THPC066

A Study of Emittance Growth in a Photoinjector Linac by using PWT as Pre-accelerator

emittance, booster, solenoid, focusing

3044

A. Sadeghipanah, S.B. Hung, W.K. Lau, A.P. Lee
NSRRC, Hsinchu, Taiwan
N.Y. Huang
NTHU, Hsinchu, Taiwan

The NSRRC high brightness photoinjector for light source R&D is a 2998 MHz split configuration. Our goal is to produce 1 nC bunch charge from a photo-cathode rf gun with normalized emittance of 1 mm-mrad or less. However, limited by the available power from our klystron, previous studies showed that our linac has to be equipped with focusing solenoid to help emittance control during acceleration. In order to omit the bulky focusing solenoid from the booster linac system, we considered to use two high gradient (~26 MV/m) PWT standing-wave structures to accelerate the beam previous to the linac. Studies showed that this configuration can keep the emittance as low as 1 mm-mrad while also decreasing the energy spread to half of its initial amount. The only drawback is the growth of final beam radius, which can be compensated by using a setting of quadrupole magnets.

THPC067

Tolerance Studies of the Max-IV Linac

quadrupole, emittance, dipole, sextupole

3047

P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
D. Angal-Kalinin, J.K. Jones, P.H. Williams
Cockcroft Institute, Warrington, Cheshire, United Kingdom
M. Eriksson, S. Thorin, S. Werin
MAX-lab, Lund, Sweden

The MAX IV linac will be used both for injection and top up into two storage rings, and as a high brightness injector for a Short Pulse Facility (SPF) and an FEL (in phase 2). We briefly describe the layout, optics and bunch compression / linearization scheme of the linac. We then investigate the robustness of the design to element errors.

THPC069

Studies to Optimize the Diamond Light Source Booster Synchrotron as a 100 MeV Storage Ring

booster, quadrupole, synchrotron, storage-ring

3053

C. Christou, M.T. Heron, J. Rowland
Diamond, Oxfordshire, United Kingdom
S. Gayadeen
University of Oxford, Oxford, United Kingdom

The injection chain for the Diamond Synchrotron Light Source consists of a 100 MeV Linac and 3 GeV booster synchrotron. These were commissioned in 2005 and 2006 respectively, and have provided acceptable performance as an injector since then. To advance a programme of work in evaluating and optimizing new control algorithms for orbit stability on the Diamond Storage Ring it was decided to use the booster synchrotron as a test platform by operating it in DC mode at 100 MeV. In support of this work and to improve the operational performance of the booster a series of studies have been carried out to better understand and characterize it. This work and the results will be presented.

THPC086

Status Report on FERMI@Elettra Project

FEL, photon, electron, undulator

3095

F. Parmigiani, M. Svandrlik, D. Zangrando
ELETTRA, Basovizza, Italy

Funding: This work was supported in part by the Italian Ministry of University and Research under grants FIRB-RBAP045JF2 and FIRB-RBAP06AWK3
FERMI@Elettra, a single-pass FEL user-facility covering the wavelength range from 100 nm (12 eV) to 3 nm (413 eV) located next to the third-generation synchrotron radiation facility Elettra in Trieste, Italy is actually under completion and will start user operation next year. The first seeded lasing was observed in December 2010 and the first experiments have started this year. In this paper an overview of the present status of machine and beamlines systems will be given as well as a status about operation and future upgrade.

THPC103

Beam Dynamics Study of X-band Linac Driven X-ray FELs

simulation, electron, FEL, optics

3128

Y. Sun, C. Adolphsen, C. Limborg-Deprey, T.O. Raubenheimer, J. Wu
SLAC, Menlo Park, California, USA

Funding: Work supported by the DOE under Contract DE-AC02-76SF00515
Several linac driven X-ray Free Electron Lasers (XFELs) are being developed to provide high brightness photon beams with very short, tunable wavelengths. In this paper, three XFEL configurations are proposed that achieve LCLS-like performance using X-band linac drivers. These linacs are more versatile, efficient and compact than ones using S-band or C-band rf technology. For each of the designs, the overall accelerator layout and the shaping of the bunch longitudinal phase space are described briefly.

THPC105

An Electron Bunch Compression Scheme for a Superconducting Radio Frequency Linear Accelerator Driven Light Source

ion, SRF, photon, FEL

3134

C. Tennant, S.V. Benson, D. Douglas, P. Evtushenko, R.A. Legg
JLAB, Newport News, Virginia, USA

Funding: Support by US DoE contract #DE-AC05-060R23177.
We describe an electron bunch compression scheme suitable for use in a light source driven by a superconducting radio frequency (SRF) linac. The key feature is the use of a recirculating linac to perform the initial bunch compression. Phasing of the second pass beam through the linac is chosen to de-chirp the electron bunch prior to acceleration to the final energy in an SRF linac ("afterburner"). The final bunch compression is then done at maximum energy. This scheme has the potential to circumvent some of the most technically challenging aspects of current longitudinal matches; namely transporting a fully compressed, high peak current electron bunch through an extended SRF environment, the need for a RF harmonic linearizer and the need for a laser heater. Additional benefits include a substantial savings in capital and operational costs by efficiently using the available SRF gradient.

THPC106

Commissioning Status of the Fritz Haber Institute THz FEL

electron, FEL, undulator, gun

3137

A.M.M. Todd, H. Bluem, V. Christina, M.D. Cole, J. Ditta, D. Dowell, K. Jordan, R. Lange, J.H. Park, J. Rathke, T. Schultheiss, L.M. Young
AES, Princeton, New Jersey, USA
W. Erlebach, S. Gewinner, H. Junkes, A. Liedke, G. Meijer, W. Schöllkopf, G. von Helden
FHI, Berlin, Germany
S.C. Gottschalk
STI, Washington, USA

The THz Free-Electron Laser (FEL) at the Fritz Haber Institute (FHI) of the Max Planck Society in Berlin is designed to deliver radiation from 3 to 300 microns using a single-plane-focusing mid-IR undulator and a two-plane-focusing far-IR undulator that acts as a waveguide for the optical mode. A key aspect of the accelerator performance is the low longitudinal emittance, < 50 keV-psec, that is specified to be delivered at 200 pC bunch charge and 50 MeV from a gridded thermionic electron source. We utilize twin accelerating structures separated by a chicane to deliver the required performance over the < 20 - 50 MeV energy range. The first structure operates at near fixed field while the second structure controls the output energy, which, under some conditions, requires running in a decelerating mode. "First Light" is targeted for the centennial of the sponsor in October 2011 and we will describe progress in the commissioning of this device to achieve this goal. Specifically, the measured performance of the accelerated electron beam will be compared to design simulations and the observed matching of the beam to the mid-IR wiggler will be described.

THPC108

Commissioning of the 50 MeV Preinjector Linac for the BESSY II Facility

booster, emittance, radiation, injection

3140

T. Atkinson, M. Helmecke, D. Schüler, E. Weihreter
HZB, Berlin, Germany
V. Dürr
BESSY GmbH, Berlin, Germany
D. Jousse, J.-L. Pastre, A.S. Setty
THALES, Colombes, France

A turn key 50MeV linac manufactured by Thales has been installed in the BESSY II facility. This linac will replace the existing Microtron injector in the near future to provide more flexible bunch population patterns for the femto-slicing operation mode and a higher single bunch intensity for top-up injection. This paper describes the essential problems which have been faced during commissioning and presents the main results obtained in the site acceptance tests including the measurement of beam emittance and energy spread.

THPC117

Analysis Quantum Efficiency Spectrum of NEA-GaAs Photocathode

electron, vacuum, cathode, brightness

3161

Y.M. Masumoto, H. Iijima, M. Kuriki
HU/AdSM, Higashi-Hiroshima, Japan

ERL is a future project of synchrotron light source with high brightness and partial coherence. ERL is based on super conducting linear accelerator providing the high brightness electron beam to insertion devices continuously. One of the most difficult technical challenge is the electron source for ERL. A photo-cathode DC biased gun is assumed, but several issues should be solved. One of the issue is the operational lifetime of cathode material, NEA GaAs. NEA stands for Negative electron affinity made by artificial treatment on clean GaAs surface. Emission from the cathode is decreased in time and extracted beam current. In order to research the phenomena, the surface potential is studied by measuring the QE　(Quantum Efficiency) spectrum. Observing temporal evolution of QE, we found that the photon energy threshold did not change during the decay. The spectrum shape was changed suggesting that the surface potential barrier becomes thicker.

THPC118

Present Status of Quantum Radiation Sources on the Basis of the S-band Compact Electron Linac

laser, electron, radiation, cavity

3164

R. Kuroda, E. Miura, H. Toyokawa, K. Yamada, E. Yamaguchi
AIST, Tsukuba, Ibaraki, Japan
M. Kumaki
RISE, Tokyo, Japan

We have developed quantum radiation sources such as a laser Compton scattering (LCS) X-ray and a coherent THz radiation sources on the basis of the S-band compact electron linac at AIST in Japan. The S-band linac consists of the laser-driven photocathode rf gun and two 1.5 m-long acceleration tubes and can accelerate the electron beam up to about 42 MeV. The LCS X-ray source can generate a quasi-monochromatic hard X-ray with variable energy of 12 - 40 keV for medical and biological applications. Now, the multi-collision LCS system has been developed with the regenerative amplifier type laser storage cavity and the multi-bunch electron beam to increase the X-ray yield. On the other hand, the high-power coherent THz radiation source has been also developed and its peak power is estimated to be more than 1 kW in frequency range between 0.1 - 2 THz. The high-power THz radiation was applied to the scanning transmission imaging. Now, the high power THz time domain spectroscopy (TDS) has been developed for the material science. In this conference, we will report the present status of the S-band compact electron linac, our quantum radiation sources and applications.

THPC123

Injector Layout and Beam Injection into Solaris

injection, gun, storage-ring, klystron

3173

A.I. Wawrzyniak, C.J. Bocchetta
Solaris, Krakow, Poland
S.C. Leemann, S. Thorin
MAX-lab, Lund, Sweden

Funding: European Regional Development Fund within the frame of the Innovative Economy Operational Program: POIG.02.01.00-12-213/09
The Solaris synchrotron radiation storage ring to be built in Krakow, Poland is based on the MAX IV 1.5 GeV design. The injector will be a linear accelerator and its components identical to those for the MAX IV project, however, injection is not at full energy and the injector layout is different. The linac and transfer line layout, optics and injection scheme into the storage ring is presented and an analysis of accumulation before energy ramping is discussed.

THPC125

Study of some Design Concepts and Collective Effects in the MAX IV Linac

emittance, simulation, sextupole, wakefield

3176

F. Curbis, M. Eriksson, O.E. Karlberg, S. Thorin, S. Werin
MAX-lab, Lund, Sweden
D. Angal-Kalinin, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

The MAX IV linac will be used both for injection and top up into two storage rings, and as a high brightness injector for a Short Pulse Facility (SPF) and an FEL (phase 2). Compression is done in two double achromats with positive R56. The natural second order momentum compaction, T566, from the achromats is used together with weak sextupoles to linearise longitudinal phase space, leaving no need for a harmonic cavity for linearization of longitudinal phase space. In this proceeding we present the design of the achromat compressors and results from particle tracking through the MAX IV linac in high brightness mode. We also investigate emittance dilution due to CSR, in the achromat compressors, and transverse wakefields in a high beta function lattice.

THPC131

MAX-IV Linac Injector Simulations including Tolerance and Jitter Analysis

gun, emittance, simulation, laser

3191

J.W. McKenzie, B.L. Militsyn
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
S. Thorin, S. Werin
MAX-lab, Lund, Sweden

The MAX-IV linac will be used both for injection and top up into two storage rings, and as a high brightness injector for a Short Pulse Facility (SPF) and an FEL (in phase 2). 100 pC bunches of electrons are created from a 1.5 cell S-band photocathode gun and subsequently accelerated up to 3 GeV by S-band linac sections. Simulations of the dynamics of the space-charge dominated beam up to 100 MeV are presented including an analysis of the tolerances required and the effects of jitter sources.

THPC133

Pre-Conceptual Design Requirements For The MaRIE Facility At LANL And The Resulting X-Ray Free Electron Laser Baseline Design

photon, electron, scattering, emittance

3197

R.L. Sheffield, B.E. Carlsten
LANL, Los Alamos, New Mexico, USA

The MaRIE (Matter-Radiation Interactions in Extremes) facility is being proposed to advance materials science by the concurrent utilization of a diverse set of highly penetrating probes. These probes will provide the basis for developing materials that will perform predictably and on demand with currently unattainable lifetimes in extreme environments. The MaRIE facilities, the Multi-Probe Diagnostic Hall (MPDH), the Fission and Fusion Materials Facility (F³), and the Making, Measuring, and Modeling Materials (M4) Facility will each have experimental needs for one or more high-energy x-ray beam probes, but all require a 50-keV coherent source of greater than 10¹0 photons in less than 1 ps. Because of space considerations at the facility, a high-gradient design is being investigated that will use a X-band RF systems to drive a 20-GeV normal-conducting linac. Experimental requirements drive a need for multiple photon bunches over time durations greater than 1 microsecond, as well as interleaving 0.1 nC very-low-emittance bunches with 2-nC electron bunches. This paper will cover an overview of the scientific requirements for the MaRIE XFEL and the baseline XFEL design.

THPC142

Burst Pulse Superimposed Electron Beam Acceleration in LEBRA FEL Linac

electron, FEL, acceleration, gun

3218

T. Tanaka, K. Hayakawa, Y. Hayakawa, M. Inagaki, K. Nakao, K. Nogami, N. Sato
LEBRA, Funabashi, Japan
S. Aizawa, Y. Arisumi, K. Shinohara
Nihon Koshuha Co. Ltd, Yokohama, Japan
I. Sato
Nihon University, Advanced Research Institute for the Sciences and Humanities, Funabashi, Japan

The electron beam for free electron laser (FEL) at the Laboratory for Electron Beam Research and Application (LEBRA) in Nihon University had been extracted from a conventional DC triode electron gun system. In conjunction with the renewal of the gun high voltage terminal a Kentech high-speed grid pulser was installed in addition to the conventional grid pulser. The 89.25MHz sine wave frequency-divided from the 2856MHz accelerating RF has been applied to the high-speed grid pulser, generating 64 or 128 frequency-divided grid pulses synchronous with the round-trip time in the FEL optical resonator. The high-speed grid pulses have been applied to the EIMAC Y646B cathode simultaneously with the conventional macropulse through the pulse coupling strip-line circuit; the resultant beam has been the short pulse beam superimposed on the macropulse beam. By reducing the macropulse voltage, only the train of the burst beam with 0.6ns width has been extracted. The peak burst beam current roughly 6 times higher than the conventional macropulse beam has been obtained with the Farady cup at the end of the FEL beamline. The FEL lasing experiment with the burst beam is underway.

THPC144

The Construction Status of Beam Transport Line from XFEL-linac to SPring-8 Storage Ring

beam-transport, lattice, alignment, storage-ring

3224

C. Mitsuda, N. Azumi, T. Fujita, K. Fukami, H. Kimura, H. Ohkuma, M. Oishi, Y. Okayasu, M. Shoji, K. Tsumaki, T. Watanabe
JASRI/SPring-8, Hyogo-ken, Japan
M. Hasegawa, Y. Maeda, T. Nakanishi, Y. Tukamoto, M. Yamashita
SES, Hyogo-pref., Japan
N. Kumagai, S. Matsui
RIKEN/SPring-8, Hyogo, Japan

The beam transport line from XFEL-linac to SPring-8 storage ring is now under construction to use the ultra short bunched electron beam at the storage ring. The newly constructed line is about 300 m, which is just a half of the whole path from the XFEL linac to the storage ring. The beam extracted from XFEL-linac is guided to the beam transport tunnel connected to the matching section of booster synchrotron bending by 55.2 degrees horizontally and by 10.0 degrees vertically. A double-bend based lattice was adopted to reasonably suppress emittance growth and bunch lengthening. Supposing a bunch length and horizontal emittance at the exit of the XFEL-linac are estimated about 100 fs and 0.04 nmrad respectively, it is expected that the current beam emittance in storage ring is improved to about 0.4 nmrad and almost same bunch length including coherent synchrotron radiation effect. In 2010, the construction of extracting part from XFEL-linac was completed and we finished the installation and alignment of main components. The conceptual design and construction status of transport line will be presented with the emphasis on the detail magnet design and the fabrication.

THPO003

Rapid-cycling Power Supplies for the J-PARC RCS Sextupole Magnets

power-supply, sextupole, synchrotron, proton

3338

Y. Watanabe
JAEA, Ibaraki-ken, Japan
T. Adachi, S. Igarashi, H. Someya
KEK, Ibaraki, Japan
N. Tani
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

The rapid-cycling synchrotron of the Japan Proton Accelerator Research Complex requires 18 sextupole magnets with three families for the chromaticity correction. One family consists of six focusing sextupole magnets, and other two families consist of six defocusing sextupole magnts. An individual power supply excited for each family and the current pattern is a DC-biased sinusoidal of a frequency of 25 Hz. This paper describes design and test results of the sextupole magnet power supplies.

THPO008

Klystron and Modulator System for the PEFP 20 MeV Proton Linac

klystron, rfq, proton, gun

3352

D.I. Kim, Y.-S. Cho, H.S. Kim, H.-J. Kwon
KAERI, Daejon, Republic of Korea

Funding: This work is supported by the Ministry of Science and Technology of the Korean government.
A modulator developed for the 100 MeV proton linear accelerator is operating in the 20 MeV proton linac. The voltage and current of the modulator are -105 kV, 50 A with 1.5 ms pulse width, 60 Hz repetition rate. The modulator drives two klystrons simultaneously, one for the RFQ, the other for the DTL. The typical operation parameters of the modulator are 85 kV of the peak voltage, 34 A of the peak current, 1 ms of the pulse width, 4 Hz of the pulse repetition. The specifications of the klystron are 350 MHz of the frequency, 1.1 MW of the maximum average RF power, less than 95 kV of the beam voltage, triode type electron gun with mod-anode. The mod-anode voltage was supplied by the voltage dividing resistors which were located inside the klystron oil tank. In this paper, the operation performance of the klystron and modulator system for the PEFP 20 MeV proton linac is presented.

THPO028

Upgrade Design of the Bump System in the J-PARC 3-GeV RCS

power-supply, injection, betatron, resonance

3403

T. Takayanagi, N. Hayashi, M. Kinsho, Y. Watanabe
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

The 3-GeV RCS aims at providing at least 300 kW output beam power with the injection beam at 181 MeV. In the second stage, the upgrade of the LINAC beam energy to 400 MeV was funded and started in March 2009. This plan will be completed in 2012. Consequently, the 3-GeV RCS will aim at 1 MW beam power. The injection bump system of the RCS is composed of the shift bump-magnets, the horizontal paint bump-magnets and the vertical paint magnets.

THPS022

Improvement of the 20 MeV Proton Accelerator at KAERI

ion-source, ion, proton, emittance

3466

H.-J. Kwon, Y.-S. Cho, J.-H. Jang, D.I. Kim, H.S. Kim, K.T. Seol, Y.-G. Song
KAERI, Daejon, Republic of Korea

Funding: This work is supported by the Ministry of Science and Technology of the Korean government.
The 20 MeV proton accelerator has been operating since 2007 when it got a operational license at Korea Atomic Energy Research Institute (KAERI) by Proton Engineering Frontier Project (PEFP). A microwave ion source was newly developed to satisfy the requirement of minimum 100 hour operation time without maintenance. After the long time operation test at test bench, it was installed to drive the 20 MeV proton accelerator. The beam profile and emittance were measured to check the characteristics of the accelerator both at the LEBT and at the end of the 20 MeV DTL. In this paper, the microwave ion source is presented and the measurement results of the beam property are discussed.

THPS025

Overview of the Status and Developments on Primary Ion Sources at CERN

ion, plasma, cathode, proton

3472

R. Scrivens, M. Kronberger, D. Kuchler, J. Lettry, O. Midttun, M.M. Paoluzzi, H. Pereira, C. Schmitzer
CERN, Geneva, Switzerland

Funding: This project has received funding from the European Community's Seventh Framework Programme (FP7/2007-2013) under the Grant Agreement no 212114.
CERN has 2 operational primary beam ion sources, that are presently used for the production of beam for LHC as well as several other facilities. Protons are produced by a duoplasmatron source, and ions from the GTS-LHC ECR ion source. In addition, new sources are required for a new 160MeV H⁻ Linac, and development has been made on a high power RF plasma generator which could serve for a future high power Linac. In this report, the present status will be given, along with operational statistics and experience for the operation sources, and the development programme reported for the future sources.

THPS038

Possibility of longitudinal painting injection with debuncher system in J-PARC linac

injection, simulation, cavity, controls

3505

G.H. Wei
KEK/JAEA, Ibaraki-Ken, Japan
M. Ikegami
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

J-PARC linac is presently operating with the output energy of 181 MeV and providing a negative hydrogen beam to the succeeding 3-GeV synchrotron. To achieve the design beam power of 1 MW from the synchrotron, we plan to upgrade the linac beam energy to 400 MeV. In the energy upgrade, we replace the debuncher system installed between the linac and synchrotron. The main roles of the debuncher system are to correct the momentum jitter and to control the momentum spread at the ring injection. Usually, we don’t assume acceleration or deceleration with the debuncher cavities except for passive momentum jitter correction. However, we are studying the possibility of actively controlling the center momentum with debuncher cavities to enable longitudinal painting injection into the succeeding ring as a potential new feature. If it finds feasible, it would provide an additional tuning knob to mitigate the beam loss in the synchrotron. In this paper, we show a beam dynamics design of the new debuncher system with emphasis on the possibility of its application for the longitudinal painting injection.

THPS050

The High Energy Beam Transport System for the European Spallation Source

target, collimation, quadrupole, octupole

3538

A.I.S. Holm, S.P. Møller, H.D. Thomsen
ISA, Aarhus, Denmark

As part of the accelerator design update for the European Spallation Source (ESS), we present results from a detailed study of the High Energy Beam Transport (HEBT) line. The HEBT is a transport line around 100 m long, which connects the 2.5-GeV linac to the target. The linac will deliver a current of 50 mA, a pulse length of 2 ms and a repetition rate of 20 Hz, and losses are of utmost importance. Presumably, the HEBT will continue the 10 m period focusing structure of the linac. Two bends – overall, achromatic – will be needed to connect the different vertical levels between the linac and the target. A number of design aspects will be discussed here: space for future linac cryostats, the need and location for collimation, the location of the tuning beam dump and the associated beam optics, and the beam expander system, which provide the desired beam footprint on the target (see also separate contribution). A proposed design including options will be described together with hardware specifications.

THPS052

Studies on Transverse Painting for H⁻ Injection into the PSB

injection, emittance, kicker, space-charge

3544

C. Bracco, C. Carli, T. Fowler, B. Goddard, G. Gräwer, J.-B. Lallement, M. Martini, M. Scholz, W.J.M. Weterings
CERN, Geneva, Switzerland

Linac4 will inject 160 MeV H− ions in to the CERN PS Booster (PSB). This will allow to reduce space charge effects and increase beam intensity but will require a substantial upgrade of the injection region, with the implementation of a charge-exchange multi-turn injection scheme. The PSB has to provide beam to several users with different requirements in terms of beam intensity and emittance. Four kicker magnets (KSW), which are already installed in the PSB lattice, will be used to accomplish painting in the horizontal phase space to match the injected beams to the required emittances. Double linear functions, with varying slopes for each user, have been defined for the KSW generators waveforms according to detailed beam dynamic studies for all target intensities and emittances. Effect of space charge, injection offsets, dispersion and betatron mismatch have been taken into account. Preliminary studies have been carried out to evaluate how to obtain the required vertical emittance and the option of a transverse painting, also in the vertical plane, is explored.

THPS059

Thermo-mechanical Design of Particle-stopping Devices at the High Energy Beamline Sections of the IFMIF/EVEDA Accelerator

simulation, ion, rfq, focusing

3562

D. Iglesias, F. Arranz, B. Brañas, J.M. Carmona, N. Casal, A. Ibarra, C. Oliver, M. Parro, I. Podadera, D. Rapisarda
CIEMAT, Madrid, Spain

Funding: Work partially supported by Spanish Ministry of Science and Innovation under project AIC10-A-000441 and ENE2009-11230.
The IFMIF/EVEDA linear accelerator is a 9 MeV, D⁺ prototype for the validation of the 40 MeV final IFMIF design. The high intensity, 125 mA CW, high power beam (1.125 MW) produces an extremely high thermal load in all the elements intercepting the ions. Independently of the final purpose of each device, if its working conditions imply stopping a non-negligible amount of particles, the associated thermal solicitation greatly determines the design constraints. The present work will summarize a thermo-mechanical design workflow that can be applied to any beam facing element of high current accelerators and its application in beam dump, scrappers and slits design. This approach is based on analysis experiences at the IFMIF/EVEDA project and, while taking into account the particularities of each device, uses the same tools and parameter evaluation criteria for all of them. It has been applied successfully to recent designs, effectively reducing the number of iterations before achieving a valid thermo-mechanical behavior. Results of each design and the concrete advantages of this approach will be detailed.

THPS064

Application of X-band 3.95 MeV Linac X-ray Source for On-site Bridge Inspection

site, target, gun, electron

3571

H.F. Jin, K. Demachi, K. Dobashi, T. Fujiwara, M. Uesaka, H. Zhu
The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan

We developed an X-ray non-destructive (NDT) system for on-site bridge inspection. A portable X-band (9.3-12 GHz) 3.95MeV linear accelerator (linac) has been developed for this system. The system consists of X-ray of 62kg without the target collimeter of 80kg, the RF power source of 62kg and other utility box of 116kg. For the onsite investigation, a flexible waveguide is used for this linac. And the linac is a point X-ray source. For X-ray detection, we chose 8-inch square size scintillation type flat panel detector. The spatial resolution of the detector is as high as 0.2mm, which is manufactured by Perkin Elmer Co. Cd2O2S:Tb is used for the scintillator crystal. The capable radiation energy range is 40keV to 15MeV. In order to realize quick inspection for a bridge, remote control robot which handles and compact X-ray source and detector are desired. Therefore, we developed 3D location system for this robot. The locating system is realized with image processing with its camera. For the operation, stereoscopic radiographic image is taken and analyzed, and computed tomography (CT) image analysis is taken for detailed inspection.
Non-destructive test (NDT) , X-ray Source, X-band, Linac, Detector, Computed Tomography (CT).

THPS065

Upgraded X-band 950 KeV Linac X-ray Source for On-site Inspection at Petrochemical Complex

status, coupling, shielding, site

3574

M. Jin, K. Demachi, K. Dobashi, H.F. Jin, T. Natsui, M. Uesaka
The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan
J. Kusano, N. Nakamura, M. Yamamoto
Accuthera Inc., Kawasaki, Kanagawa, Japan
E. Tanabe
AET, Kawasaki-City, Japan

Abstract―Our portable X-band (9.3GHz) 950KeV linac has been successfully upgraded. The problems of RF power oscillation, beam current oscillation and reduction and finally lack of X-ray intensity were solved by replacing the axial coupling cavities with the side-coupled ones. Designed X-ray dose rate of 0.05 Sv/min@1m is going to be achieved. Length of the accelerating tube is reduced to less than 25 cm. X-ray source part with the local radiation shielding is connected by the flexible waveguide with the box of the 300 kW　magnetron and cooling unit. The total system consists of the three suit-case-size units, the last of which is one for the electric power supply. Even on-line dynamic transmission imaging is available by using the high intensity X-ray camera. Demonstration of the measurement of wall thinning of metal pipes with thick thermal shielding is under way. Updated measurement results will be presented. KEYWORDS: portable X-band linac X-ray source, on-site high energy X-ray inspection, petrochemical complex

THPS066

Technical Overview of the SIEMENS Particle Therapy Accelerator

ion, synchrotron, proton, extraction

3577

V. Lazarev, O. Chubarov, S. Emhofer, G. Franzini, S. Göller, B. Nagorny, A. Robin, H. Rohdjess, R. Rottenbach, A.C. Sauer, R. Schedler, T. Sieber, B. Steiner, J. Tacke, D.B. Thorn, T. Uhl, P. Urschütz, O. Wilhelmi
Siemens Med, Erlangen, Germany
M. Budde, J.S. Gretlund, H.B. Jeppesen, C.V. Nielsen, C.G. Pedersen, Ka.T. Therkildsen, S.V. Weber
Siemens DK, Jyllinge, Denmark

Siemens has developed an accelerator system for particle therapy. It consists of an injector (7 MeV/u protons and light ions) and a compact synchrotron able to accelerate proton beams up to 250 MeV and carbon ions up to 430 MeV/u. These beams are extracted slowly from the synchrotron and delivered to a number of beam ports. The first accelerator system has been built and commissioned up to the first two beam outlets. An overview of the achieved performance of the system is presented.
*Particle therapy is a work in progress and requires country-specific regulatory approval prior to clinical use.

THPS070

Status Report of the CNAO Construction and Commissioning

proton, synchrotron, extraction, ion

3589

M. Pullia
CNAO Foundation, Milan, Italy

The CNAO (National Center for Oncological Hadrontherapy) is the first Italian center for deep hadrontherapy. The main accelerator is a synchrotron, based on the PIMMS design, capable to accelerate carbon ions up to 400 MeV/u and protons up to 250 MeV. Four treatment lines, in three treatment rooms, are foreseen in a first stage. The CNAO facility, has been designed for a completely active beam delivery system, in which a pencil beam is scanned transversely and the extracted beam energy can be changed on a spill to spill basis. The commissioning of the synchrotron started in August 2010. At the beginning of 2011 the first Spread Out Bragg Peaks with proton beams in the energy range 120-170 MeV/u, matching the first foreseen treatments, have been measured. The commissioning of the machine with protons has now been completed and authorisation to treatment of patients has been obtained from the competent authorities. The commissioning with carbon ions is in progress.

THPS076

Sub-mm Therapeutic Carbon-Ion Irradiation Port in Gunma University

ion, betatron, lattice, synchrotron

3607

K. Torikai, T. Kanai, N.T. Nakano, H. Shimada, E. Takeshita, M. Tashiro, S. Yamada, K. Yusa
Gunma University, Heavy-Ion Medical Research Center, Maebashi-Gunma, Japan
K. Hanakawa, T. Honda, K. Yoshida
Mitsubishi Electric Corporation, Kobe, Japan

Funding: This Study was done by Grant-in-Aid for Scientific Research (KAKENHI).
One of advantage of particle therapy is concentration of irradiation dose. In April 2011, we developed "in-body-focusing type" irradiation port for "Proof-of-Principle" . This sub-mm port produces 1mm(1σ) beam. we will explain this irradion port at the conference.

THPS078

Medical Applications of INR Proton Linac

proton, neutron, target, isotope-production

3613

S.V. Akulinichev, L.V. Kravchuk
RAS/INR, Moscow, Russia

The main parameters of INR proton linac are suitable for several medical applications. The isotope laboratory of INR is now producing Sr-82 for PET diagnostics in cardiology and the first proton therapy treatment room is now being tested. This treatment room was designed for the therapy of tumors of different sizes and localizations, the patient position can be either sitting or lying. The combination of scatterers and collimators makes the formed beam profile at the isocenter insensitive to the initial beam profile in the transport channel. During the linac run for medicine at the end of 2010 the proton beams with energies of 120-209 MeV have been shown to fulfilled the medical requirements. Due to high maximal intensity of the proton beam, the brachytherapy source activation and the neutron therapy can become other applications of the facility. It is possible to use the parasitic neutrons, arising at the isotope laboratory or at some installations of the experimental complex, for the activation of medical sources with ytterbium or other nuclides, for the neutron therapy and even for the boron or gadolinium neutron-capture therapy of radio-resistant tumors.

THPS094

New Approaches in High Power RFQ Technology

rfq, vacuum, resonance, RF-structure

3654

A. Bechtold, J.M. Maus, G. Ritter
NTG Neue Technologien GmbH & Co KG, Gelnhausen, Germany

There is a clear tendency for the utilization of continuous wave c.w. high power RFQs in a huge variety of applications like nuclear waste transmutation or material research. They can serve as injectors for the production of secondary particles like neutrons or rare isotopes and can be applied for post acceleration of the latter ones. These RF-structures have to withstand an enormous amount of RF-power dissipated on the surfaces (up to several 10s kW per meter) and the associated thermal load. NTG Company gained lots of experience especially in the field of 4-rod c.w. RFQ design. Most recent developments to handle such high RF-power dissipation shall be reported.

THPS101

Present and Perspectives of the Sparc THz Source

radiation, electron, polarization, single-bunch

3669

E. Chiadroni, M. Bellaveglia, M. Boscolo, M. Castellano, G. Di Pirro, M. Ferrario, G. Gatti, E. Pace, C. Vaccarezza
INFN/LNF, Frascati (Roma), Italy
P. Calvani, S. Lupi, A. Nucara
Università di Roma I La Sapienza, Roma, Italy
L. Catani, B. Marchetti
INFN-Roma II, Roma, Italy
A. Cianchi
Università di Roma II Tor Vergata, Roma, Italy
O. Limaj
University of Rome La Sapienza, Rome, Italy
A. Mostacci, L. Palumbo
Rome University La Sapienza, Roma, Italy
C. Ronsivalle
ENEA C.R. Frascati, Frascati (Roma), Italy

The development of radiation sources in the THz spectral region has become more and more interesting because of the peculiar characteristics of this radiation: it is non ionizing, it penetrates dielectrics, it is highly absorbed by polar liquids, highly reflected by metals and reveals specific "fingerprint" absorption spectra arising from fundamentals physical processes. The THz source at SPARC is an accelerator based source for research investigations (e.g. material science, biology fields). Its measured peak power is of the order of 10⁸ W, very competitive with respect to other present sources. The present status of the source is presented and future perspectives are presented.

THPS102

Novel Schemes for the Narrow Band Sparc THz Source using a Comb like e-beam

radiation, cavity, electron, laser

3672

B. Marchetti
INFN-Roma II, Roma, Italy
M. Boscolo, M. Castellano, E. Chiadroni, M. Ferrario, B. Spataro, C. Vaccarezza
INFN/LNF, Frascati (Roma), Italy
A. Cianchi
Università di Roma II Tor Vergata, Roma, Italy
C. Ronsivalle
ENEA C.R. Frascati, Frascati (Roma), Italy

The development of radiation sources in the THz spectral region has become more and more interesting because of the peculiar characteristics of this radiation: it is non ionizing, it penetrates dielectrics, it is highly absorbed by polar liquids, highly reflected by metals and reveals specific "fingerprint" absorption spectra arising from fundamentals physical processes. The THz source at SPARC is an accelerator based source for research investigations (e.g. material science, biology fields). By means of e-beam manipulation technique, a longitudinal modulated beam, the so-called comb beam, can be produced at Sparc. In terms of THz sources, such e-beam distribution allows to produce high intensitiy narrow band THz radiation, whose spectrum strongly depends on the charge distribution inside the e-beam. Different linac schemes are compared. In particular, spectra obtained using the comb-beam compression through velocity bunching including a IV harmonic RF section is showed.

THPS103

The Proton Engineering Frontier Project: Status and Prospect of Proton Beam Utilization

proton, target, radiation, DTL

3675

K. R. Kim, Y.-S. Cho, B.H. Choi, J-Y. Kim, K.Y. Kim, J. W. Park
KAERI, Daejon, Republic of Korea

Funding: This work has been supported by the Ministry of Education, Science, and Technology, Republic of Korea.
A 100-MeV, 20-mA high intensity proton linac is to be constructed in 2012 by the PEFP (Proton Engineering Frontier Project) of the Korea Atomic Energy Research Institute, which was started in 2002 with three main objectives; development of high intensity proton linac, development of proton beam utilization technologies, and industrialization of developed technologies. Proton beams with variable energy and current can be provided to the users from various research and application fields such as nano-, bio-, semiconductor-, space-, radiation-, environment-technologies and medical- and basic sciences, etc. through 10 targets rooms, which are assigned specific application fields to meet various user’s beam requirements. Following a brief introduction to the accelerator development, multiple beamline development and the construction works, we will review the achievements of our user program which have been operated over the past 8 years to cultivate and foster proton beam users and beam utilization technologies in diverse R&D fields. In addition, we will discuss the perspectives of the beam utilization in conjunction with design and construction of user facilities.

THPZ015

Synchrotron Radiation in the Interaction Region for a Ring-Ring and Linac-Ring LHeC

radiation, interaction-region, electron, luminosity

3717

N.R. Bernard
UCLA, Los Angeles, California, USA
R. Appleby, L.N.S. Thompson
UMAN, Manchester, United Kingdom
N.R. Bernard
ETH, Zurich, Switzerland
B.J. Holzer, R. Tomás, F. Zimmermann
CERN, Geneva, Switzerland
M. Klein
The University of Liverpool, Liverpool, United Kingdom
P. Kostka
DESY Zeuthen, Zeuthen, Germany
B. Nagorny, U. Schneekloth
DESY, Hamburg, Germany

The Large Hadron electron Collider (LHeC) aims at bringing hadron-lepton collisions to CERN with center of mass energies in the TeV scale. The LHeC will utilize the existing LHC storage ring with the addition of a 60 GeV electron accelerator. The electron beam will be stored and accelerated in either a storage ring in the LHC tunnel (Ring-Ring) or a linac tangent to the LHC tunnel (Linac-Ring). Synchrotron Radiation (SR) in the Interaction Region (IR) of this machine requires an iterative design process in which luminosity is optimized while the SR is minimized. This process also requires attention to be given to the detector as the beam pipe must be designed such that damaging effects, such as out-gasing, are minimized while the tracking remains close to the IP. The machinery of GEANT4 has been used to simulate the SR load in the IR and also to design absorbers/masks to shield SR from backscattering into the detector or propagating with the electron beam. The outcome of these simulations, as well as cross checks, are described in the accompanying poster which characterizes the current status of the IR design for both the Ring-Ring and Linac-Ring options of the LHeC in terms of SR.

THPZ019

High Luminosity Electron-hadron Collider eRHIC

electron, hadron, luminosity, proton

3726

V. Ptitsyn, E.C. Aschenauer, J. Beebe-Wang, S.A. Belomestnykh, I. Ben-Zvi, R. Calaga, X. Chang, A.V. Fedotov, H. Hahn, L.R. Hammons, Y. Hao, P. He, A.K. Jain, E.C. Johnson, D. Kayran, J. Kewisch, V. Litvinenko, G.J. Mahler, W. Meng, B. Parker, A.I. Pikin, T. Rao, T. Roser, B. Sheehy, J. Skaritka, R. Than, D. Trbojevic, N. Tsoupas, J.E. Tuozzolo, G. Wang, Q. Wu, W. Xu
BNL, Upton, Long Island, New York, USA

We present the design of a future high-energy high-luminosity electron-hadron collider at RHIC called eRHIC. We plan adding 20 (30) GeV energy recovery linacs to accelerate and to collide polarized and unpolarized electrons with hadrons in RHIC. The center-of-mass energy of eRHIC will range from 30 to 200 GeV. The luminosity exceeding 10³4 cm^-2s⁻¹ can be achieved in eRHIC using the low-beta interaction region which a 10 mrad crab crossing. A natural staging scenario of step-by-step increases of the electron beam energy by builiding-up of eRHIC's SRF linacs. We report on the eRHIC design and cost estimates for it stages. We discuss the progress of eRHC R&D projects from the polarized electron source to the coherent electron cooling.

THPZ021

Effect of Coherent Synchrotron Radiation at the SuperKEKB Damping Ring

vacuum, emittance, damping, wakefield

3732

H. Ikeda, T. Abe, M. Kikuchi, K. Oide, K. Shibata, M. Tobiyama, D.M. Zhou
KEK, Ibaraki, Japan

The longitudinal wake field dominated by the CSR is important at the SuperKEKB damping ring. The peak of the CSR wake field is 100 times higher than those of the vacuum chamber components. We calculated the CSR effect for different vacuum chamber cross-sections, and adopted one which reduced longitudinal instability.

THPZ024

Updated Design of the Italian SuperB Factory Injection System

injection, positron, electron, emittance

3738

S. Guiducci, M.E. Biagini, R. Boni, M.A. Preger, P. Raimondi
INFN/LNF, Frascati (Roma), Italy
J. Brossard, O. Dadoun, P. Lepercq, C. Rimbault, A. Variola
LAL, Orsay, France
A. Chancé
CEA, Gif-sur-Yvette, France
J.T. Seeman
SLAC, Menlo Park, California, USA

The ultra high luminosity B-factory (SuperB) project of INFN requires a high performance and reliable injection system, providing electrons at 4 GeV and positrons at 7 GeV, to fulfill the very tight requirements of the collider. Due to the short beam lifetime, continuous injection of electrons and positrons in both HER and LER rings is necessary to keep the average luminosity at a high level. An updated version of the injection system, optimized at higher repetition frequency is presented. This scheme includes a polarized electron gun, a positron production scheme with electron/positron conversion at low energy 0.6 GeV, and a 1 GeV damping ring to reduce the injected emittance of the positron beam.

FRYBA01

The European Spallation Source

cavity, target, proton, HOM

3789

S. Peggs
ESS, Lund, Sweden

The principles of the design, and the technical and beam dynamics challenges of the ESS are presented, as well as possible future upgrade options.

Slides FRYBA01 [5.122 MB]