LINAC2014 - List of Keywords (quadrupole)

Paper	Title	Other Keywords	Page
MOIOC02	Single-Knob Beam Line for Transverse Emittance Partitioning	emittance, solenoid, coupling, scattering	36
	C. Xiao, L. Groening, O.K. Kester, H. Leibrock, M.T. Maier, P. Rottländer GSI, Darmstadt, Germany M. Chung UNIST, Ulsan, Republic of Korea
	Flat beams feature unequal emittances in the horizontal and vertical phase space. Such beams were created successfully in electron machines by applying effective stand-alone solenoid fringe fields in the electron gun. Extension of this method to ion beams was proposed conceptually. The present paper is on the decoupling capabilities of an ion beam emittance transfer line. The proposed beam line provides a single-knob tool to partition the horizontal and vertical rms emittances, while keeping the product of the two emittances constant as well as the transverse rms Twiss parameters (αx,y and βx,y) in both planes. It is shown that this single knob is the solenoid field strength, and now we fully understand the decoupling features.
	Slides MOIOC02 [1.327 MB]

MOIOC03	Model and Beam Based Setup Procedures for a High Power Hadron Superconducting Linac	cavity, linac, simulation, laser	41
	A.P. Shishlo ORNL, Oak Ridge, Tennessee, USA
	This presentation will review methods for experimental determination of optimal operational set points in a multi-cavity superconducting high power hadron linac. A typical tuning process, including establishing correct acceleration profile and RMS bunch size matching, is based on comparison between measured data and the results of simulations from envelope, single and multi-particle models. Presence of significant space charge effects requires simulation and measurement of bunch dynamics in 3 dimensions to ensure low loss beam transport. This is especially difficult in a superconducting linac where use of interceptive diagnostics is usually restricted because of the risk of SRF cavity surface contamination. The procedures discussed here are based on non-interceptive diagnostics such as beam position monitors and laser wires, and conventional diagnostics devices such as wire scanners and bunch shape monitors installed outside the superconducting linac. The longitudinal Twiss analysis based on the BPM signals will be described. The superconducting SNS linac tuning experience will be used to demonstrate problems and their solution for real world linac tune-up procedures.
	Slides MOIOC03 [1.954 MB]

MOPP015	High Energy Electron Radiography Experiment Research Based on Picosecond Pulse-width Bunch	experiment, electron, linac, proton	76
	Q.T. Zhao, S. Cao, R. Cheng, X.K. Shen, Z.M. Zhang, Y.T. Zhao IMP, Lanzhou, People's Republic of China Y.-C. Du TUB, Beijing, People's Republic of China W. Gai ANL, Argonne, Illinois, USA
	A new scheme is proposed that high energy electron beam as a probe is used for time resolved imaging measurement of high energy density materials, especially for high energy density matter and inertial confinement fusion. The first picosecond pulse-width electron radiography experiment was achieved by Institute of Modern Physics, Chinese Academy of Sciences and Tinghua University (THU), based on THU Linear electron accelerator (LINAC). It is used for principle test and certifying that this kind of LINAC with ultra-short pulse electron bunch can be used for electron radiography. The experiment results, such as magnifying factor and the imaging distortion, are consistent with the beam optical theory well. The 2.5 um RMS spatial resolution has been gotten with magnifying factor 46, with no optimization the imaging lens section. It is found that in the certain range of magnifying factor, the RMS spatial resolution will get better with bigger magnifying factor. The details of experiment set up, results, analysis and discussions are presented here.
	Poster MOPP015 [2.866 MB]

MOPP030	CALIFES: A Multi-Purpose Electron Beam for Accelerator Technology Tests	electron, wakefield, acceleration, laser	121
	J.L. Navarro Quirante, R. Corsini, W. Farabolini, D. Gamba, A. Grudiev, M.A. Khan, T. Lefèvre, S. Mazzoni, R. Pan, F. Peauger, F. Tecker, N. Vitoratou, K. Yaqub CERN, Geneva, Switzerland W. Farabolini, F. Peauger CEA/DSM/IRFU, France D. Gamba JAI, Oxford, United Kingdom M.A. Khan, K. Yaqub PINSTECH, Islamabad, Pakistan J. Ögren, R.J.M.Y. Ruber Uppsala University, Uppsala, Sweden N. Vitoratou Thessaloniki University, Thessaloniki, Greece
	The Compact Linear Collider (CLIC) project aims to accelerate and collide electrons and positrons up to 3 TeV center-of-mass energy using a novel two-beam acceleration concept. To prove the feasibility of this technology the CLIC Test Facility CTF3 has been operated during the last years. CALIFES (Concept d’Accélérateur Linéaire pour Faisceau d’Electron Sonde) is an electron linac hosted in the CTF3 complex, which provides a flexible electron beam and the necessary equipment to probe both the two-beam acceleration concept and novel instrumentation to be used in the future CLIC collider. In this paper we describe the CALIFES Linac and its beam characteristics, present recent test results, outline its future program on two-beam module testing and finally discuss about possible future applications as a multi-purpose accelerator technology test facility.

MOPP032	Experimental Verification Towards Feed-Forward Ground Motion Mitigation at ATF2	ground-motion, simulation, feedback, controls	124
	J. Pfingstner, K. Artoos, C. Charrondière, S.M. Janssens, M. Patecki, Y. Renier, D. Schulte, R. Tomás CERN, Geneva, Switzerland A. Jeremie IN2P3-LAPP, Annecy-le-Vieux, France K. Kubo, S. Kuroda, T. Naito, T. Okugi, T. Tauchi, N. Terunuma KEK, Ibaraki, Japan
	Without counter measures, ground motion effects would deteriorate the performance of future linear colliders to an unacceptable level. An envisioned new ground motion mitigation method (based on feed-forward control) has the potential to improve the performance and to reduce the system cost compared to other proposed methods. For the experimental verification of this feed-forward scheme, a dedicated measurement setup has been installed at ATF2 at KEK. In this paper, the progress on this experimental verification is described. An important part of the feed-forward scheme could be already demonstrated, namely the prediction of the orbit jitter due to ground motion measurements.

MOPP034	Beam Dynamics Studies of the CLIC Drive Beam Injector	bunching, emittance, cavity, focusing	131
	S. Sanaye Hajari, S. Döbert, H. Shaker CERN, Geneva, Switzerland S. Sanaye Hajari, H. Shaker IPM, Tehran, Iran
	In the Compact Linear Collider (CLIC) the RF power for the acceleration of the Main Beam is extracted from a high-current Drive Beam that runs parallel with the main linac. The beam in the Drive Beam Accelerator is phase coded. This means only every second accelerator bucket is occupied. However, a few percent of particles are captured in wrong buckets, called satellite bunches. The phase coding is done via a sub-harmonic bunching system operating at a half the acceleration frequency. The beam dynamics of the Drive Beam injector complex has been studied in detail and optimised. The model consists of a thermionic gun, the bunching system followed by some accelerating structures and a magnetic chicane. The bunching system contains three sub-harmonic bunchers, a prebuncher and a tapered travelling wave buncher all embedded in a solenoidal magnetic field. The simulation of the beam dynamics has been carried out with PARMELA with the goal of optimising the overall bunching process and in particular decreasing the satellite population and the beam loss in magnetic chicane and in transverse plane limiting the beam emittance growth.

MOPP039	Dynamics of Bunches Partially Chopped with the MEBT Chopper in the ESS Linac	linac, DTL, lattice, simulation	146
	R. Miyamoto, B. Cheymol, R. De Prisco, M. Eshraqi, A. Ponton, E. Sargsyan ESS, Lund, Sweden I. Bustinduy ESS Bilbao, Bilbao, Spain
	The front-end of a hadron linac typically has a transient time during turning on and off and bunches in the head and tail of a pulse from this period likely have wrong parameters and a risk to cause beam losses. A risk of losses must be avoided as possible in a high power machine so these bunches are removed with deflectors called choppers in the ESS Linac. From experiences of other machines, a rise time of a chopper as fast as one RF period (2.84~ns for ESS) is challenging to achieve and not necessarily needed with no ring to inject like ESS, and hence a 10~ns rise time is planned for a chopper in the medium energy beam transport of ESS. This, however, means that several bunches receive intermediate deflections and may propagate with large trajectory excursions. This paper studies dynamics of such partially chopped bunches in detail to ensure no significant loss is caused by them.

MOPP066	High Gradient CH-Type Cavity Development for 10 – 100 AMeV Beams	cavity, linac, ion, heavy-ion	208
	A. Almomani, U. Ratzinger IAP, Frankfurt am Main, Germany
	Funding: This work is supported by Federal Ministry of Education and Research - BMBF No. 05P12RFRB9. The development in pulsed linac activities aims on compact designs and on an increase of the voltage gain per meter. At IAP - Frankfurt, a CH design was developed for these studies, where the mean effective accelerating field is expected to reach well above 10 MV/m at 325 MHz, β=0.164. Within a funded project, this cavity is systematically developed. Currently, the cavity is under construction at NTG GmbH and expected to be ready for copper plating in autumn 2014. The results should give an impact on the rebuilt of the UNILAC - Alvarez section, optimized for achieving the beam intensities specified for the GSI – FAIR project. A mid- and long- term aim is a compact pulsed high current linac. The new GSI 3 MW Thales klystron test stand will be very important for these investigations. Detailed studies on two different types of copper plating can be performed on this cavity. Additionally, operating of normal conducting cavities at cryogenic temperatures will be discussed. In this work, the cavity status will be presented.

MOPP080	Beam Dynamics Study for RAON Superconducting Linac	linac, ion, lattice, proton	239
	H. Jang, H.J. Kim IBS, Daejeon, Republic of Korea J.G. Hwang KNU, Deagu, Republic of Korea B.H. Oh POSTECH, Pohang, Kyungbuk, Republic of Korea
	Rare Isotope Science Project (RISP) in Korea is going to build an ion accelerator, RAON which can generate and accelerate various stable ions such as uranium, proton, xenon and rare isotopes such as tin, nickel. Linear accelerators of RAON adopted superconducting RF cavities and warm quadruple doublet structure. In RAON, there are two low energy linacs which can accelerate the Uranium beam from 0.5MeV/u to 17.5MeV/u, charge stripping sections and one high energy linac which can accelerate the Uranium beam up to 200MeV/u. Due to the diversity of planned ions and isotopes, their A/q range lies widely from 1 to 8. As a result, the research related with linac lattice design and beam dynamics is one of the important topics to build RAON. In this presentation the current status of RAON linac lattice design and the beam dynamics simulation results for acceleration of various ions will be described.

MOPP082	Superconducting Linac for RISP	linac, cavity, cryomodule, ion	245
	H.J. Kim, H.J. Cha, M.O. Hyun, H.C. Jung, Y.J.K. Kim, M. Lee IBS, Daejeon, Republic of Korea
	The RISP (Rare Isotope Science Project) has been proposed as a multi-purpose accelerator facility for providing beams of exotic rare isotopes of various energies. It can deliver ions from proton to Uranium. Proton and Uranium beams are accelerated upto 600 MeV and 200 MeV/u respectively. The facility consists of three superconducting linacs of which superconducting cavities are independently phased. Requirement of the linac design is especially high for acceleration of multiple charge beams. In this paper, we present the RISP linac design, the prototyping of superconducting cavity and cryomodule.

MOPP088	MUNES a Compact Neutron Source for BNCT and Radioactive Wastes Characterization	neutron, rfq, target, proton	261
	A. Pisent, P. Colautti, E. Fagotti INFN/LNL, Legnaro (PD), Italy
	At INFN LNL (Legnaro Italy) it has been built a high intensity Radio Frequency Quadrupole (RFQ) structure, able to produce a 5 MeV proton beam of 30 mA. Coupled with a Be target such a beam can generate a neutron flux of 10¹⁴ n/s, with a spectrum centered in the MeV region (that has been recently characterized in detail at LNL accelerators). This neutron flux can be moderated to generate a thermal or epithermal source for BNCT with very little contamination of energetic form energetic neutron and gamma. Since the approval of MUNES project (in 2012) the high technology issues related to a compact neutron source to be installed in an Hospital environment have been faced. In particular for the powering of the accelerating structure an innovative system, completely based on solid state amplifiers, has been developed and ordered to industry. An outline of MUNES design and the status of the project will be given in the paper.

MOPP095	Emittance Measurement for SPring-8 Linac Using Four Six-Electrode BPMs	emittance, linac, electron, focusing	279
	K. Yanagida, H. Hanaki, S. Suzuki JASRI/SPring-8, Hyogo-ken, Japan
	In the SPring-8 linear accelerator (linac) six-electrode beam position monitors (BPMs) have been installed to measure second-order moments. At the end of the linac where the electron beam energy is 1 GeV four quadrupole magnets are utilized for twiss parameter matching toward the following beam transport line. Last year four six-electrode BPMs were installed at the locations of these four quadrupole magnets for an emittance measurement. The relative second-order moments were obtained changing the magnetic field strength of the quadrupole magnets, then beam sizes, emittances and twiss parameters were deduced or calculated. At this time we applied one pair of beam sizes measured by the screen monitor for a precise determination of emittances but we try to implement non-destructive measurement with no screen monitor. Before the emittance measurement a calibration with fifth-order moment correction was carried out changing beam positions at the BPM locations using upstream steering magnets (the entire calibration).
	Slides MOPP095 [0.984 MB]

MOPP099	Compact Proton Injector for Synchrotrons	rfq, linac, proton, cavity	291
	A.D. Kovalenko, A.V. Butenko JINR, Dubna, Moscow Region, Russia A. Kolomiets, A.S. Plastun ITEP, Moscow, Russia
	Compact linac comprising two sections of different RFQ structures was designed. The first section is conventional RFQ with output energy 3 MeV whereas the second one is RFQ with trapezoidal modulation of vanes. The linac output energy is 8 MeV. The both structures operate at frequency of 352 MHz. The total length of machine is less than 8 m. The output pulsed beam current is of 40 mA. The design is suitable for both as NICA injection complex and proton superconducting medical synchrotron.

MOPP120	Beam Dynamic Design of a 100 mA, 162.5 Mhz High-Current Linac	rfq, linac, emittance, experiment	336
	F.J. Jia, J.E. Chen, Y.R. Lu, Z. Wang, W.L. Xia, X.Q. Yan, K. Zhu PKU, Beijing, People's Republic of China W.P. Dou, Y. He IMP, Lanzhou, People's Republic of China
	Funding: This work is supported by the 973 program (No. 2014CB845503) and the NSFC (Grants No. 11079001). The beam dynamic design of a 100 mA, 162.5 MHz Radio Frequency Quadrupole (RFQ) is presented in this paper. The RFQ will accelerate protons from 85 keV to 3 MeV under the operation mode of continuous-wave (CW). The code PARMTEQM is used to carry out the beam dynamics design and the transmission efficiency has been optimized and improved to more than 99%. In the design of this high-current linac, the space charge effect is analyzed as it can cause emittance growth, nonuniform particle density distribution and resonance effect. The electrode structure parameters generated by PARMTEQM also be adopted by the code of Toutatis to verify the result’s veracity.

TUPP004	An In-flight Radioactive Ion Separator Design for the ATLAS Facility	dipole, ion, target, simulation	446
	B. Mustapha, B. Back, C.R. Hoffman, B.P. Kay, J.A. Nolen, P.N. Ostroumov ANL, Argonne, USA
	Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357. An in-flight radioactive beam separator, named AIRIS, is being designed to enhance the radioactive beam capabilities of the ATLAS facility at Argonne. In order to serve all the experimental areas while maintaining the stable beam capabilities, the separator design is of broadband type. This design allows the selected radioactive beam to come back on the ATLAS beam line while stable beams continue on the same straight line with the separator turned off. The separation is performed in two steps, the first is magnetic in a chicane made of four magnets and four multipoles, while the second uses an rf sweeper taking advantage of the time separation between the beam of interest and potential contaminants including the primary beam tail. We will report on the progress of the AIRIS design effort with special emphasis on the performance of the rf sweeper.

TUPP019	Qualification of the Titanium Welds in the E-XFEL Cryomodule and the CE Certification	cryomodule, cavity, operation, linac	468
	S. Barbanotti, H. Hintz, K. Jensch, R. Klos, W. Maschmann, A. Matheisen, A. Schmidt DESY, Hamburg, Germany C. Boulch, C. Cloué, C. Madec, J.L. Perrin, T. Trublet CEA/IRFU, Gif-sur-Yvette, France J.-P. Charrier, O. Napoly CEA/DSM/IRFU, France
	The CE stamping of the one hundred 1.3 GHz cryomodules for the XFEL Linac is a main step in the process of the certification of the entire Linac as a pressure equipment. Stringent requirements on materials and the quality of the welds of the pressurised components need to be satisfied to obtain the stamp. This paper summarizes these requirements, describes the process developed to qualify each module and summarises the rework campaign on the cavity helium vessels made necessary to obtain the required quality for a reliable and safe accelerator.

TUPP025	Progress on ESS Medium Energy Beam Transport	linac, rfq, cavity, DTL	484
	I. Bustinduy, D. Fernandez-Cañoto, N. Garmendia, A. Ghiglino, O. González, P.J. González, Z. Izaola, I. Madariaga, M. Magan, L. Muguira, J.L. Muñoz, I. Rueda, F. Sordo, S. Varnasseri, R. Vivanco ESS Bilbao, Bilbao, Spain M. Eshraqi, R. Miyamoto, A. Ponton ESS, Lund, Sweden
	The considered versatile ESS MEBT is being designed to achieve four main goals: First, to contain a fast chopper and its correspondent beam dump, that could serve in the commissioning as well as in the ramp up phases. A detailed study of the chopper rise time effects on the loss budget will be presented. Second, to serve as a halo scraping section by means of various adjustable blades. Third, to measure the beam phase and proﬁle between the RFQ and the DTL, along with other beam monitors. And ﬁnally, to match the RFQ output beam characteristics to the DTL input both transversally and longitudinally. For this purpose a set of eleven quadrupoles is used to match the beam characteristics transversally, combined with three 352.2 MHz CCL type buncher cavities, which are used to adjust the beam in order to fulfil the required longitudinal parameters. A thorough study on the optimal input beam parameters will be discussed. Quadrupole design update will be presented along with new RF measurements over the buncher prototype. Finally, updated results will be presented on the chopper and beam-dump system.
	Poster TUPP025 [5.596 MB]

TUPP037	Transverse Emittance Measurements of the REX-ISOLDE Beams in Preparation for the HIE-ISOLDE Commissioning	emittance, linac, background, ion	513
	D. Voulot, M.A. Fraser, D. Lanaia CERN, Geneva, Switzerland T. Olsson MAX-lab, Lund, Sweden
	The transverse emittance at the output of the REX-ISOLDE normal conducting linac has been measured at different energies in order to characterise the beam at injection to the future HIE-ISOLDE superconducting linac. The measurements were done with low intensity stable beams (~0.5 enA) in order to avoid compensation effects in the EBIS ion source and obtain representative measurements of the radioactive ion beam emittance. Emittances were measured using a slit-grid emittance meter and compared with results obtained with a quadrupole-scan (three-gradient) method. An analysis of the background suppression is presented and possible source of errors for both type of measurements are discussed.
	Poster TUPP037 [2.084 MB]

TUPP038	Transverse Beam Profile Measurements in the Linac4 Medium Energy Beam Transport	emittance, simulation, linac, rfq	516
	M. Yarmohammadi Satri, G. Bellodi, V.A. Dimov, J.-B. Lallement, A.M. Lombardi, U. Raich, F. Roncarolo, F. Zocca CERN, Geneva, Switzerland
	Linac4 is a 160 MeV H⁻ linear accelerator presently under construction at CERN. It will replace the present 50 MeV proton Linac2 as injector of the proton accelerator complex as part of a project to increase the LHC luminosity. The Linac4 front-end, composed of a 45 keV ion source, a Low Energy Beam Transport (LEBT), a 352.2 MHz Radio Frequency Quadrupole (RFQ) which accelerates the beam to 3 MeV and a Medium Energy Beam Transport (MEBT) housing a beam chopper, has been commissioned in the Linac4 tunnel. The MEBT is composed of three buncher cavities and 11 quadrupole magnets to match the beam from the RFQ to the next accelerating structure (DTL) and it includes two wire scanners for beam profile measurement. In this paper we present the results of the profile measurements and we compare them with emittance measurements taken with a temporary slit-and-grid emittance measurement device located after the MEBT line.

TUPP039	Accuracy Determination of the ESS MEBT Emittance Measurements	emittance, scattering, proton, linac	519
	B. Cheymol, A. Ponton ESS, Lund, Sweden
	The European Spallation Source MEBT will be equipped with a full set of diagnostics in order to characterize the bean properties before the injection in the DTL. The 6D phase space of the beam shall be characterize during the commissioning of the normal conducting as well as on regular basis during retuning phase of the machine. In this paper we will discuss the accuracy of the transverse emittance measurement that will be performed with the slit-grid method. The slit geometric parameters have been determined in order to achieve the required resolution and sensitivity. Scattering effects at the slit have been considered to determine the emittance measurement accuracy.

TUPP047	PXIE RFQ Bead Pull Measurements	rfq, beam-transport, cavity, experiment	535
	P. Berrutti, T.N. Khabiboulline, V. Poloubotko, G.V. Romanov, J. Steimel, V.P. Yakovlev Fermilab, Batavia, Illinois, USA D. Li, J.W. Staples LBNL, Berkeley, California, USA
	Funding: Work supported by D.O.E. Contract No. DE-AC02-07CH11359 Project X Injector Experiment radio frequency quadrupole has recently been built for Fermilab by Berkley laboratory. This RFQ will be placed after the low energy beam transport (LEBT) and before the medium energy beam transport (MEBT). The RFQ will operate at 162.5 MHz in CW regime; its function is to accelerate and focus particles coming from the LEBT at 30 keV, and to deliver a beam at 2.1 MeV to the MEBT. In order to make sure that the RFQ meets the specifications of field flatness and frequency the field in the vanes should be measured using bead pull technique. FNAL created a new single wire bead pull set up for the RFQ of PXIE. The measurements are used to find the electrical center of the structure, then the amplitude of the electromagnetic field in all the sectors of the RFQ; and the tuning will be based on these measurements. This paper describes the bead pull experimental set up, the software developed for this particular application and the measurements taken.
	Poster TUPP047 [1.089 MB]

TUPP054	Study of Beam-Based Alignment for the LCLS-II SC Linac	linac, emittance, alignment, cryomodule	544
	A. Saini, N. Solyak, V.P. Yakovlev Fermilab, Batavia, Illinois, USA T.O. Raubenheimer SLAC, Menlo Park, California, USA
	The Linac Coherent Light Source (LCLS) is an x-ray free electron laser facility. The proposed upgrade of the LCLS facility is based on construction of 4 GeV superconducting (SC) linac. The achievable performance of linac is determined by beam sensitivity to various component errors. In this paper we review misalignment tolerances of LCLS-II SC linac and discuss possible beam-based alignment algorithm to meet these tolerances.

TUPP057	In Situ Measurement of Mechanical Vibrations of a 4-Rod RFQ at GSI	laser, rfq, operation, vacuum	553
	P. Gerhard, L. Groening, K.-O. Voss GSI, Darmstadt, Germany
	A new 4-rod CW Radio Frequency Quadrupole was commissioned at the high charge state injector HLI at the UNILAC in 2009. It is in operation since 2010. At high rf amplitudes strong modulations of the rf reflection emerge, with a modulation frequency of approximately 500 Hz. They are attributed to mechanical oscillations of the rods, excited by the rf pulse. The high fraction of reflected rf power severely limits the pulse length and rf amplitude achievable. As these modulations could only be seen during the rf pulse by means of rf measurements, a direct observation of the mechanical vibrations was desirable. Such measurements have been conducted using a commercial laser vibrometer, allowing for the investigation of the mechanical behavior of the RFQ independent of the presence of rf power. After a short introduction of the method, the results will be presented and compared with rf measurements and simulations. : P. Gerhard et al., “Experience with a 4–Rod CW RFQ”, LINAC’12, Sept. 2012, Tel Aviv, THPB035

TUPP059	Advanced Beam Matching to a High Current RFQ	rfq, simulation, emittance, ion	559
	S.G. Yaramyshev, W.A. Barth, L.A. Dahl, P. Gerhard, L. Groening, M.T. Maier, S. Mickat, A. Orzhekhovskaya, B. Schlitt, H. Vormann GSI, Darmstadt, Germany
	The High Current Injector (HSI) of the heavy ion linac UNILAC at GSI comprises the transport lines, the RFQ and two DTL tanks. Beam matching to the RFQ acceptance with a magnetic quadrupole quartet has been worked out manually during commissioning and operation of the machine. Due to a strong overlapping of the field from neighboring quadrupole lenses, a standard optics calculation does not provide for the required reliability. Advanced beam dynamics simulations have been done with the macroparticle code DYNAMION. The superposition of the measured magnetic fields of each quadrupole was taken into account. The quadrupole settings were optimized using the Monte-Carlo method. Two solutions have been found in accordance with the general theory of particle optics. Beam dynamics simulations with new quadrupole settings show an increased particle transmission through the RFQ. The results of numerical study have been confirmed during experimental campaigns. An improved performance of the whole HSI has been demonstrated. The proposed algorithm and a comparison of the measured data with result of simulations are presented.

TUPP062	A Rebunching CH Cavity for Intense Proton Beams	linac, multipole, cavity, simulation	566
	M. Schwarz, C. Claessens, M. Heilmann, O. Hinrichs, D. Koser, O. Meusel, D. Mäder, H. Podlech, U. Ratzinger, A. Seibel IAP, Frankfurt am Main, Germany
	Funding: Project supported by the EU, FP7 MAX, Contract No. 269565 The Frankfurt Neutron Source at the Stern-Gerlach-Zentrum (FRANZ) will provide ultra short neutron pulses at high intensities and repetition rates. The facility is currently under construction at the Goethe-University in Frankfurt am Main (Germany). A 5-Gap CH rebuncher is installed behind a coupled RFQ/IH-DTL combination at the end of the LINAC section between two magnetic quadrupole triplets. It will be used for varying the final proton energy as well as for focusing the bunch longitudinally to compensate huge space charge forces at currents up to 200 mA at the final stage of extension. High current beam dynamic simulations have been performed. They include benchmarking of different beam dynamic codes like LORASR and TraceWin, as well as validating the results by measurements. Detailed examination of multipole field impact, due to the cavity’s geometry, together with error tolerance studies and thermal simulations are also performed. Furthermore, this CH rebuncher serves as a prototype for rt CH cavities at MYRRHA (Belgium), an Accelerator Driven System for transmutation of high level nuclear waste. After copper plating the cavity, RF conditioning will start soon.
	Poster TUPP062 [6.015 MB]

TUPP063	Improvements of the LORASR Code and their Impact on Current Beam Dynamics Designs	linac, proton, DTL, focusing	569
	R. Tiede, D. Mäder, N.F. Petry, H. Podlech, U. Ratzinger, C. Zhang IAP, Frankfurt am Main, Germany
	LORASR is a multi-particle tracking code optimized for the beam dynamics design of ‘Combined Zero Degree Structure (KONUS)’ lattices, which can benefit from an adapted input file structure and code architecture. Recent code developments focused on the implementation of tools for machine error studies and loss profile investigations, including also steering correction strategies. These tools are a stringent necessity for the design of high intensity linacs. Thus, the abilities of the present LORASR release allow performing a manifold of checks and optimizations before finalizing the layouts of KONUS-based or conventional linacs. Two representative examples are the MAX-MYRRHA Injector and the GSI FAIR Facility Proton Linac, both under development with strong participation of IAP, Frankfurt University. This paper presents the status of the LORASR code development with focus on the new features and illustrates the impact on current designs by examples taken from the above-mentioned projects.

TUPP075	The First Beam Recirculation and Beam Tuning in the Compact ERL at KEK	linac, operation, emittance, recirculation	599
	S. Sakanaka, M. Adachi, S. Adachi, M. Akemoto, D.A. Arakawa, S. Asaoka, K. Enami, K. Endo, S. Fukuda, T. Furuya, K. Haga, K. Hara, K. Harada, T. Honda, Y. Honda, H. Honma, T. Honma, K. Hosoyama, K. Hozumi, A. Ishii, X. Jin, E. Kako, Y. Kamiya, H. Katagiri, H. Kawata, Y. Kobayashi, Y. Kojima, Y. Kondou, O.A. Konstantinova, T. Kume, T. Matsumoto, H. Matsumura, H. Matsushita, S. Michizono, T. Miura, T. Miyajima, H. Miyauchi, S. Nagahashi, H. Nakai, H. Nakajima, N. Nakamura, K. Nakanishi, K. Nakao, K.N. Nigorikawa, T. Nogami, S. Noguchi, S. Nozawa, T. Obina, T. Ozaki, F. Qiu, H. Sagehashi, H. Sakai, S. Sasaki, K. Satoh, M. Satoh, T. Shidara, M. Shimada, K. Shinoe, T. Shioya, T. Shishido, M. Tadano, T. Tahara, T. Takahashi, R. Takai, H. Takaki, T. Takenaka, Y. Tanimoto, M. Tobiyama, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, K. Watanabe, M. Yamamoto, Y. Yamamoto, Y. Yano, M. Yoshida KEK, Ibaraki, Japan E. Cenni Sokendai, Ibaraki, Japan R. Hajima, S. Matsuba, R. Nagai, N. Nishimori, M. Sawamura, T. Shizuma JAEA, Ibaraki-ken, Japan J.G. Hwang KNU, Deagu, Republic of Korea M. Kuriki, Y. Seimiya HU/AdSM, Higashi-Hiroshima, Japan A. Valloni CERN, Geneva, Switzerland
	Superconducting(SC)-linac-based light sources, which can produce ultra-brilliant photon beams in CW operation, are attracting worldwide attention. In KEK, we have been conducting R&D efforts towards the energy-recovery-linac(ERL)-based light source* since 2006. To demonstrate the key technologies for the ERL, we constructed the Compact ERL (cERL)** from 2009 to 2013. In the cERL, high-brightness CW electron beams are produced using a 500-kV photocathode DC gun. The beams are accelerated using SC cavities, transported through a recirculation loop, decelerated in the SC cavities, and dumped. In the February of 2014, we succeeded in accelerating and recirculating the CW beams of 4.5 micro-amperes in the cERL; the beams were successfully transported from the gun to the beam dump under energy recovery operation in the main linac. Then, precise tuning of beam optics and diagnostics of beam properties are under way. We report our experience on the beam commissioning, as well as the results of initial measurements of beam properties. * N. Nakamura, IPAC2012, TUXB02. ** S. Sakanaka et al., IPAC2013, WEPWA015.

TUPP090	Spatially Periodic RF Quadrupole LINAC	focusing, linac, ion, lattice	634
	A.S. Plastun, A. Kolomiets ITEP, Moscow, Russia
	Spatially-periodic RF quadrupole structure is proposed as second section of front end of ion linac. It consists of conventional drift tubes and RF quadrupoles. Quadrupoles are 4-vane segments with nonzero electric potential on the longitudinal axis. Thus the accelerating electric field is formed between drift tubes and RF quadrupoles. Moreover accelerating field can be provided even inside the RF quadrupoles. It allows building structures with different focusing lattices and provides high energy gain rate.
	Poster TUPP090 [7.706 MB]

TUPP119	Design Studies for Medium and High beta SCRF Cavities for Indian Spallation Neutron Source	cavity, linac, HOM, lattice	699
	A.R. Jana, V. Kumar RRCAT, Indore, India
	There is a plan to build a 1 GeV H⁻ linac for the proposed Indian Spallation Neutron Source (ISNS) at Raja Ramanna Centre for Advanced Technology (RRCAT), Indore. The medium and high energy section of the ISNS linac will consist of beta_g=0.61, as well as beta_g = 0.9, 650 MHz, 5-cell superconducting radiofrequency (SCRF) cavities, for which detailed electromagnetic design studies have been performed. During our design study, we have evolved a generalized procedure for the optimization of geometrical parameters of multi-cell SCRF cavities. Studies on higher order modes supported by the cavity and its effect on beam dynamics, as well as on heat load to the cavity have been performed, which constitute an important aspect of the design study. Finally, detailed studies on Lorentz Force Detuning (LFD) have been performed, and design of the cavity has been optimized to minimize the effect due to the LFD. The paper discussed the details of the calculations and the studies that have been performed during the design study.

WEIOA01	Construction and RF Conditioning of the Cell-Coupled Drift Tube Linac (CCDTL) for Linac4 at CERN	linac, vacuum, coupling, cavity	746
	A.G. Tribendis, Y.A. Biryuchevsky, E. Kendjebulatov, Ya.G. Kruchkov, E. Rotov, A.A. Zhukov BINP SB RAS, Novosibirsk, Russia Y. Cuvet, A. Dallocchio, J.-F. Fuchs, F. Gerigk, J.-M. Giguet, J. Hansen, T. Muranaka, E. Page, B. Riffaud, N. Thaus, M. Tortrat, M. Vretenar, R. Wegner CERN, Geneva, Switzerland M.Y. Naumenko RFNC-VNIITF, Snezhinsk, Chelyabinsk region, Russia
	This paper reports on the construction experience of the Linac4 CCDTL, which took place in two Russian institutes in the framework of three ISTC projects in close collaboration with CERN. The tanks were constructed at VNIITF, Snezhinsk, while the drift tubes and supports were made at BINP, Novosibirsk. All structures were then assembled and tuned at BINP before shipment to CERN where the high-power conditioning took place. The tuning principles, quality checks and conditioning results are presented.
	Slides WEIOA01 [4.909 MB]

THPP032	Magnetic Characterization of Fast-Pulsed Quadrupole Magnets for Linac4	linac, flattop, power-supply, target	909
	S. Kasaei, M.C.L. Buzio, O. Crettiez, V. Della Selva, L. Fiscarelli, J. Garcia Perez, J.-B. Lallement CERN, Geneva, Switzerland
	Linac4, currently being built at CERN, includes 24 quadrupole magnets characterized by narrow apertures and fast excitation cycles which make accurate magnetic measurements challenging. This paper describes the method used for the measurement, which is a combination of techniques based on stretched wire, rotating and fixed search coils. We show how these different instruments can be used in a complementary way to derive information on different aspects of the magnetic behaviour, such as the impact of hysteresis and dynamic eddy current effects. We summarize the results of the series measurement campaign, which include field strength, harmonic components, and the offset and orientation of the magnetic axis. Finally, we discuss the relevance of these measurements as their impact to the operation of the linac.

THPP033	Linac4 Transverse and Longitudinal Emittance Reconstruction in the Presence of Space Charge	emittance, linac, simulation, rfq	913
	J.-B. Lallement, G. Bellodi, V.A. Dimov, A.M. Lombardi, M. Yarmohammadi Satri CERN, Geneva, Switzerland M. Yarmohammadi Satri IPM, Tehran, Iran
	Linac4 is a pulsed, normal-conducting 160 Mev H⁻ linear accelerator presently under construction at CERN. It will replace the present 50 MeV Linac2 as injector of the proton accelerator complex as part of a project to increase the LHC luminosity. The 3 MeV front end, composed of a 45 keV ion source, a Low Energy Beam transport (LEBT), a 352 MHz Radio Frequency Quadrupole (RFQ) at 3 MeV and Medium Energy Beam Transport (MEBT) housing a beam chopper, and the first Drift Tube Linac (DTL) tank at 12 MeV have been commissioned during the first half of 2014. The transverse and longitudinal emittance reconstruction technique in the presence of space charge, that will be used for the next commissioning stages and permanently during the Linac operation, was successfully tested and validated. The reconstruction method and the results obtained at 3 and 12 MeV are presented in this paper.

THPP035	Deceleration Measurements of an Electron Beam in the CLIC Test Facility 3	electron, lattice, acceleration, linear-collider	920
	R.L. Lillestøl, S. Döbert CERN, Geneva, Switzerland E. Adli University of Oslo, Oslo, Norway
	The Test Beam Line at the CLIC Test Facility 3 at CERN is a proof-of-principle of the future CLIC decelerators, which will extract a large amount of beam energy for acceleration of the main CLIC beams. The current beamline consists of a FODO lattice with 13 Power Extraction and Transfer Structures (PETS). We discuss beam deceleration measurements of up to 37 %, taking into account effects from the bunch length and the bunch phase. The 12 GHz phase is reproduced based on measurements in a PETS with an uncombined beam. The spectrometer measurements are also compared to predictions based on the beam current and on the produced rf power in the PETS, as well as particle tracking simulations with the Placet code.

THPP040	A Compact High-Frequency RFQ for Medical Applications	rfq, linac, proton, cavity	935
	M. Vretenar, A. Dallocchio, V.A. Dimov, M. Garlaschè, A. Grudiev, A.M. Lombardi, S.J. Mathot, E. Montesinos, M.A. Timmins CERN, Geneva, Switzerland
	In the frame of a new program for medical applications, CERN has designed and is presently constructing a compact 750 MHz Radio Frequency Quadrupole to be used as injector for hadron therapy linacs. The RFQ reaches an energy of 5 MeV in only 2 meters; it is divided into four standardized modules of 500 mm, each equipped with 12 tuner ports and one RF input. The inner quadrant radius is 46 mm and the RFQ has an outer diameter of 134 mm; its total weight is only 220 kg. The beam dynamics and RF design have been optimized for reduced length and minimum RF power consumption; construction techniques have been adapted for future industrial production. The multiple RF ports are foreseen for using either 4 solid-state units or 4 IOT’s as RF power sources. Although hadron therapy requires only a low duty cycle, the RFQ has been designed for 5% duty cycle in view of other uses. This extremely compact and economical RFQ design opens several new perspectives for medical applications, in particular for PET isotopes production in hospitals with two coupled high-frequency RFQs reaching 10 MeV and for Technetium production for SPECT tomography with two RFQs followed by a DTL.

THPP042	Error Study on the Normal Conducting ESS Linac	emittance, DTL, linac, rfq	942
	R. De Prisco, M. Eshraqi, R. Miyamoto, E. Sargsyan ESS, Lund, Sweden A.R. Karlsson Lund University, Lund, Sweden
	One of the preliminary, but important test to evaluate the robustness of the accelerator design is performing the statistical error study by introducing realistic tolerances on the machine components. In this paper the guidelines to define the tolerances and the correction system are summarized in order to validate the design. Firstly statistical studies have been performed in order to define the sensitivity to single errors and to fix the tolerances. Then all errors, within the previous defined tolerances, are applied with the correction system to evaluate the beam quality and to check if the system guarantees a radiologically safe operation.

THPP045	ESS Linac Beam Modes	rfq, linac, emittance, DTL	951
	E. Sargsyan, R. Miyamoto ESS, Lund, Sweden
	The ESS Linac will ultimately deliver 5 MW of beam power to the target with a long-pulse structure of 2.86 ms and 14 Hz repetition rate, which is essential for the production of long-wavelength neutrons [1]. Ten different beam power levels are requested for the operation. In order to preserve the required time structure of the beam, different beam power levels will be produced by reducing the beam current in ten regular steps using an iris with an adjustable aperture in the LEBT. Low current and low emittance beams may as well be useful for the beam commissioning of the Linac. This paper describes the generation and the beam dynamics of different beam modes in the ESS Linac.

THPP071	Proposal of a 325 MHz Ladder-RFQ for the FAIR Proton-Linac	rfq, proton, simulation, dipole	1016
	M. Schütt, U. Ratzinger IAP, Frankfurt am Main, Germany R. M. Brodhage GSI, Darmstadt, Germany
	Funding: BMBF 05P12RFRB9 For the research program with cooled antiprotons at FAIR a dedicated 70 MeV, 70 mA proton injector is required. The first rf accelerator element is a 325 MHz RFQ accelerating from 95 keV to 3.0 MeV. RFQ’s beyond 300 MHz were realized in 4-Vane-type geometry so far. At IAP there is a tradition in 4-Rod-type RFQ development. This type of RFQ is dominating at lower frequencies. Very promising results have been reached with a ladder type-RFQ, which has been investigated during 2013. In comparison with a traditional 4-Rod RFQ approach the geometry is more convenient at high frequencies. We will show most recent 3D simulations of the frequency tuning possibilities and of a whole cavity demonstrating the power of a ladder type RFQ. An RFQ layout for the new FAIR proton injector will be shown. (see also R. Brodhage, U. Ratzinger, A. Almomani, “Design Study of a High Frequency Proton Ladder RFQ” , Proc. of the 2013 IPAC Conference, Shanghai, China, p. 3788.)

THPP087	ESS DTL Design and Drift Tube Prototypes	DTL, linac, coupling, vacuum	1050
	F. Grespan, M. Comunian, A. Pisent, M. Poggi, C. R. Roncolato INFN/LNL, Legnaro (PD), Italy P. Mereu INFN-Torino, Torino, Italy
	The Drift Tube Linac (DTL) for the ESS accelerator will accelerate protons up to 62.5 mA average pulse current from 3.62 to 90 MeV. The 5 tanks composing the DTL are designed to operate at 352.2 MHz in pulses of 2.86 ms long with a repetition rate of 14 Hz. The accelerating field is around 3.1 MV/m, constant in each tank. Permanent magnet quadrupoles (PMQs) are used as focusing element in a FODO lattice. The empty drift tubes accommodate Electro Magnetic Dipoles (EMDs) and Beam Position Monitors (BPMs) in order to implement beam corrective schemes. A complete set of Drift Tubes is under construction that is BPM, EMD and PMQ types. These prototypes are aimed to validate the design with the involved integration issues of the various components, as well as the overall technological and assembly process. This paper presents the main mechanical choices and the status of the prototyping program of the Drift Tubes.

THPP091	Installation and Performance Check of Beam Monitors for Energy Upgraded J-PARC Linac	linac, operation, cavity, acceleration	1059
	A. Miura, K. Hasegawa, H. Oguri, N. Ouchi JAEA/J-PARC, Tokai-mura, Japan M. Ikegami FRIB, East Lansing, Michigan, USA Y. Liu KEK/JAEA, Ibaraki-Ken, Japan T. Maruta J-PARC, KEK & JAEA, Ibaraki-ken, Japan T. Miyao KEK, Ibaraki, Japan
	An energy upgrade project has started to achieve the design beam power of 1 MW at the exit of the downstream synchrotron in the J-PARC Linac since 2009. In the upgraded project, a beam energy in the Linac has increased from present 181 MeV to 400 MeV using the additional 21 annular-ring coupled structure (ACS) cavities. The new beam monitors as the beam current monitors, the phase monitors, the beam position monitors, the transverse profile monitors (wire scanner monitors) and the longitudinal profile monitors (bunch shape monitors) for the part where the ACS cavities were installed were designed, fabricated and calibrated. Till the end of November, 2013, all beam monitors were completed to be installed. From the middle of December, we started the beam commissioning to achieve the beam energy as 400 MeV, as well as to confirm the beam monitor functioning. We achieved the 400 MeV beam acceleration at the middle of January, 2014 using newly installed beam monitors. This paper describes the beam monitor installation, calibration and the beam commissioning results of beam monitor functioning.

THPP097	3D Effects in RFQ Accelerators	rfq, simulation, cavity, emittance	1077
	S.S. Kurennoy LANL, Los Alamos, New Mexico, USA
	RFQ accelerators are usually designed and modeled with standard codes based on electrostatic approximations. Recent examples show that this approach fails to accurately predict the performance for 4-rod RFQs: 3D RF effects near the vane ends can noticeably influence the beam dynamics. The same applies to any RFQ where the quadrupole symmetry is broken, e.g., 4-vane RFQ with windows. We analyzed two 201.25-MHz 4-rod RFQs – one recently commissioned at FNAL and a new design for LANL – using 3D modeling with CST Studio. In both cases the manufacturer CAD RFQ model was imported into CST. The electromagnetic analysis with MicroWave Studio (MWS) was followed by beam dynamics modeling with Particle Studio (PS). For the LANL RFQ with duty factor up to 15%, a thermal-stress analysis with ANSYS was also performed. The simulation results for FNAL RFQ helped our Fermilab colleagues fix the low output beam energy. The LANL RFQ design was modified after CST simulations indicated insufficient tuning range and incorrect output energy; the modified version satisfies the design requirements.

Paper

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MOIOC02

Single-Knob Beam Line for Transverse Emittance Partitioning

emittance, solenoid, coupling, scattering

36

C. Xiao, L. Groening, O.K. Kester, H. Leibrock, M.T. Maier, P. Rottländer
GSI, Darmstadt, Germany
M. Chung
UNIST, Ulsan, Republic of Korea

Flat beams feature unequal emittances in the horizontal and vertical phase space. Such beams were created successfully in electron machines by applying effective stand-alone solenoid fringe fields in the electron gun. Extension of this method to ion beams was proposed conceptually. The present paper is on the decoupling capabilities of an ion beam emittance transfer line. The proposed beam line provides a single-knob tool to partition the horizontal and vertical rms emittances, while keeping the product of the two emittances constant as well as the transverse rms Twiss parameters (αx,y and βx,y) in both planes. It is shown that this single knob is the solenoid field strength, and now we fully understand the decoupling features.

Slides MOIOC02 [1.327 MB]

MOIOC03

Model and Beam Based Setup Procedures for a High Power Hadron Superconducting Linac

cavity, linac, simulation, laser

41

A.P. Shishlo
ORNL, Oak Ridge, Tennessee, USA

This presentation will review methods for experimental determination of optimal operational set points in a multi-cavity superconducting high power hadron linac. A typical tuning process, including establishing correct acceleration profile and RMS bunch size matching, is based on comparison between measured data and the results of simulations from envelope, single and multi-particle models. Presence of significant space charge effects requires simulation and measurement of bunch dynamics in 3 dimensions to ensure low loss beam transport. This is especially difficult in a superconducting linac where use of interceptive diagnostics is usually restricted because of the risk of SRF cavity surface contamination. The procedures discussed here are based on non-interceptive diagnostics such as beam position monitors and laser wires, and conventional diagnostics devices such as wire scanners and bunch shape monitors installed outside the superconducting linac. The longitudinal Twiss analysis based on the BPM signals will be described. The superconducting SNS linac tuning experience will be used to demonstrate problems and their solution for real world linac tune-up procedures.

Slides MOIOC03 [1.954 MB]

MOPP015

High Energy Electron Radiography Experiment Research Based on Picosecond Pulse-width Bunch

experiment, electron, linac, proton

76

Q.T. Zhao, S. Cao, R. Cheng, X.K. Shen, Z.M. Zhang, Y.T. Zhao
IMP, Lanzhou, People's Republic of China
Y.-C. Du
TUB, Beijing, People's Republic of China
W. Gai
ANL, Argonne, Illinois, USA

A new scheme is proposed that high energy electron beam as a probe is used for time resolved imaging measurement of high energy density materials, especially for high energy density matter and inertial confinement fusion. The first picosecond pulse-width electron radiography experiment was achieved by Institute of Modern Physics, Chinese Academy of Sciences and Tinghua University (THU), based on THU Linear electron accelerator (LINAC). It is used for principle test and certifying that this kind of LINAC with ultra-short pulse electron bunch can be used for electron radiography. The experiment results, such as magnifying factor and the imaging distortion, are consistent with the beam optical theory well. The 2.5 um RMS spatial resolution has been gotten with magnifying factor 46, with no optimization the imaging lens section. It is found that in the certain range of magnifying factor, the RMS spatial resolution will get better with bigger magnifying factor. The details of experiment set up, results, analysis and discussions are presented here.

Poster MOPP015 [2.866 MB]

MOPP030

CALIFES: A Multi-Purpose Electron Beam for Accelerator Technology Tests

electron, wakefield, acceleration, laser

121

J.L. Navarro Quirante, R. Corsini, W. Farabolini, D. Gamba, A. Grudiev, M.A. Khan, T. Lefèvre, S. Mazzoni, R. Pan, F. Peauger, F. Tecker, N. Vitoratou, K. Yaqub
CERN, Geneva, Switzerland
W. Farabolini, F. Peauger
CEA/DSM/IRFU, France
D. Gamba
JAI, Oxford, United Kingdom
M.A. Khan, K. Yaqub
PINSTECH, Islamabad, Pakistan
J. Ögren, R.J.M.Y. Ruber
Uppsala University, Uppsala, Sweden
N. Vitoratou
Thessaloniki University, Thessaloniki, Greece

The Compact Linear Collider (CLIC) project aims to accelerate and collide electrons and positrons up to 3 TeV center-of-mass energy using a novel two-beam acceleration concept. To prove the feasibility of this technology the CLIC Test Facility CTF3 has been operated during the last years. CALIFES (Concept d’Accélérateur Linéaire pour Faisceau d’Electron Sonde) is an electron linac hosted in the CTF3 complex, which provides a flexible electron beam and the necessary equipment to probe both the two-beam acceleration concept and novel instrumentation to be used in the future CLIC collider. In this paper we describe the CALIFES Linac and its beam characteristics, present recent test results, outline its future program on two-beam module testing and finally discuss about possible future applications as a multi-purpose accelerator technology test facility.

MOPP032

Experimental Verification Towards Feed-Forward Ground Motion Mitigation at ATF2

ground-motion, simulation, feedback, controls

124

J. Pfingstner, K. Artoos, C. Charrondière, S.M. Janssens, M. Patecki, Y. Renier, D. Schulte, R. Tomás
CERN, Geneva, Switzerland
A. Jeremie
IN2P3-LAPP, Annecy-le-Vieux, France
K. Kubo, S. Kuroda, T. Naito, T. Okugi, T. Tauchi, N. Terunuma
KEK, Ibaraki, Japan

Without counter measures, ground motion effects would deteriorate the performance of future linear colliders to an unacceptable level. An envisioned new ground motion mitigation method (based on feed-forward control) has the potential to improve the performance and to reduce the system cost compared to other proposed methods. For the experimental verification of this feed-forward scheme, a dedicated measurement setup has been installed at ATF2 at KEK. In this paper, the progress on this experimental verification is described. An important part of the feed-forward scheme could be already demonstrated, namely the prediction of the orbit jitter due to ground motion measurements.

MOPP034

Beam Dynamics Studies of the CLIC Drive Beam Injector

bunching, emittance, cavity, focusing

131

S. Sanaye Hajari, S. Döbert, H. Shaker
CERN, Geneva, Switzerland
S. Sanaye Hajari, H. Shaker
IPM, Tehran, Iran

In the Compact Linear Collider (CLIC) the RF power for the acceleration of the Main Beam is extracted from a high-current Drive Beam that runs parallel with the main linac. The beam in the Drive Beam Accelerator is phase coded. This means only every second accelerator bucket is occupied. However, a few percent of particles are captured in wrong buckets, called satellite bunches. The phase coding is done via a sub-harmonic bunching system operating at a half the acceleration frequency. The beam dynamics of the Drive Beam injector complex has been studied in detail and optimised. The model consists of a thermionic gun, the bunching system followed by some accelerating structures and a magnetic chicane. The bunching system contains three sub-harmonic bunchers, a prebuncher and a tapered travelling wave buncher all embedded in a solenoidal magnetic field. The simulation of the beam dynamics has been carried out with PARMELA with the goal of optimising the overall bunching process and in particular decreasing the satellite population and the beam loss in magnetic chicane and in transverse plane limiting the beam emittance growth.

MOPP039

Dynamics of Bunches Partially Chopped with the MEBT Chopper in the ESS Linac

linac, DTL, lattice, simulation

146

R. Miyamoto, B. Cheymol, R. De Prisco, M. Eshraqi, A. Ponton, E. Sargsyan
ESS, Lund, Sweden
I. Bustinduy
ESS Bilbao, Bilbao, Spain

The front-end of a hadron linac typically has a transient time during turning on and off and bunches in the head and tail of a pulse from this period likely have wrong parameters and a risk to cause beam losses. A risk of losses must be avoided as possible in a high power machine so these bunches are removed with deflectors called choppers in the ESS Linac. From experiences of other machines, a rise time of a chopper as fast as one RF period (2.84~ns for ESS) is challenging to achieve and not necessarily needed with no ring to inject like ESS, and hence a 10~ns rise time is planned for a chopper in the medium energy beam transport of ESS. This, however, means that several bunches receive intermediate deflections and may propagate with large trajectory excursions. This paper studies dynamics of such partially chopped bunches in detail to ensure no significant loss is caused by them.

MOPP066

High Gradient CH-Type Cavity Development for 10 – 100 AMeV Beams

cavity, linac, ion, heavy-ion

208

A. Almomani, U. Ratzinger
IAP, Frankfurt am Main, Germany

Funding: This work is supported by Federal Ministry of Education and Research - BMBF No. 05P12RFRB9.
The development in pulsed linac activities aims on compact designs and on an increase of the voltage gain per meter. At IAP - Frankfurt, a CH design was developed for these studies, where the mean effective accelerating field is expected to reach well above 10 MV/m at 325 MHz, β=0.164. Within a funded project, this cavity is systematically developed. Currently, the cavity is under construction at NTG GmbH and expected to be ready for copper plating in autumn 2014. The results should give an impact on the rebuilt of the UNILAC - Alvarez section, optimized for achieving the beam intensities specified for the GSI – FAIR project. A mid- and long- term aim is a compact pulsed high current linac. The new GSI 3 MW Thales klystron test stand will be very important for these investigations. Detailed studies on two different types of copper plating can be performed on this cavity. Additionally, operating of normal conducting cavities at cryogenic temperatures will be discussed. In this work, the cavity status will be presented.

MOPP080

Beam Dynamics Study for RAON Superconducting Linac

linac, ion, lattice, proton

239

H. Jang, H.J. Kim
IBS, Daejeon, Republic of Korea
J.G. Hwang
KNU, Deagu, Republic of Korea
B.H. Oh
POSTECH, Pohang, Kyungbuk, Republic of Korea

Rare Isotope Science Project (RISP) in Korea is going to build an ion accelerator, RAON which can generate and accelerate various stable ions such as uranium, proton, xenon and rare isotopes such as tin, nickel. Linear accelerators of RAON adopted superconducting RF cavities and warm quadruple doublet structure. In RAON, there are two low energy linacs which can accelerate the Uranium beam from 0.5MeV/u to 17.5MeV/u, charge stripping sections and one high energy linac which can accelerate the Uranium beam up to 200MeV/u. Due to the diversity of planned ions and isotopes, their A/q range lies widely from 1 to 8. As a result, the research related with linac lattice design and beam dynamics is one of the important topics to build RAON. In this presentation the current status of RAON linac lattice design and the beam dynamics simulation results for acceleration of various ions will be described.

MOPP082

Superconducting Linac for RISP

linac, cavity, cryomodule, ion

245

H.J. Kim, H.J. Cha, M.O. Hyun, H.C. Jung, Y.J.K. Kim, M. Lee
IBS, Daejeon, Republic of Korea

The RISP (Rare Isotope Science Project) has been proposed as a multi-purpose accelerator facility for providing beams of exotic rare isotopes of various energies. It can deliver ions from proton to Uranium. Proton and Uranium beams are accelerated upto 600 MeV and 200 MeV/u respectively. The facility consists of three superconducting linacs of which superconducting cavities are independently phased. Requirement of the linac design is especially high for acceleration of multiple charge beams. In this paper, we present the RISP linac design, the prototyping of superconducting cavity and cryomodule.

MOPP088

MUNES a Compact Neutron Source for BNCT and Radioactive Wastes Characterization

neutron, rfq, target, proton

261

A. Pisent, P. Colautti, E. Fagotti
INFN/LNL, Legnaro (PD), Italy

At INFN LNL (Legnaro Italy) it has been built a high intensity Radio Frequency Quadrupole (RFQ) structure, able to produce a 5 MeV proton beam of 30 mA. Coupled with a Be target such a beam can generate a neutron flux of 10¹⁴ n/s, with a spectrum centered in the MeV region (that has been recently characterized in detail at LNL accelerators). This neutron flux can be moderated to generate a thermal or epithermal source for BNCT with very little contamination of energetic form energetic neutron and gamma. Since the approval of MUNES project (in 2012) the high technology issues related to a compact neutron source to be installed in an Hospital environment have been faced. In particular for the powering of the accelerating structure an innovative system, completely based on solid state amplifiers, has been developed and ordered to industry. An outline of MUNES design and the status of the project will be given in the paper.

MOPP095

Emittance Measurement for SPring-8 Linac Using Four Six-Electrode BPMs

emittance, linac, electron, focusing

279

K. Yanagida, H. Hanaki, S. Suzuki
JASRI/SPring-8, Hyogo-ken, Japan

In the SPring-8 linear accelerator (linac) six-electrode beam position monitors (BPMs) have been installed to measure second-order moments. At the end of the linac where the electron beam energy is 1 GeV four quadrupole magnets are utilized for twiss parameter matching toward the following beam transport line. Last year four six-electrode BPMs were installed at the locations of these four quadrupole magnets for an emittance measurement. The relative second-order moments were obtained changing the magnetic field strength of the quadrupole magnets, then beam sizes, emittances and twiss parameters were deduced or calculated. At this time we applied one pair of beam sizes measured by the screen monitor for a precise determination of emittances but we try to implement non-destructive measurement with no screen monitor. Before the emittance measurement a calibration with fifth-order moment correction was carried out changing beam positions at the BPM locations using upstream steering magnets (the entire calibration).

Slides MOPP095 [0.984 MB]

MOPP099

Compact Proton Injector for Synchrotrons

rfq, linac, proton, cavity

291

A.D. Kovalenko, A.V. Butenko
JINR, Dubna, Moscow Region, Russia
A. Kolomiets, A.S. Plastun
ITEP, Moscow, Russia

Compact linac comprising two sections of different RFQ structures was designed. The first section is conventional RFQ with output energy 3 MeV whereas the second one is RFQ with trapezoidal modulation of vanes. The linac output energy is 8 MeV. The both structures operate at frequency of 352 MHz. The total length of machine is less than 8 m. The output pulsed beam current is of 40 mA. The design is suitable for both as NICA injection complex and proton superconducting medical synchrotron.

MOPP120

Beam Dynamic Design of a 100 mA, 162.5 Mhz High-Current Linac

rfq, linac, emittance, experiment

336

F.J. Jia, J.E. Chen, Y.R. Lu, Z. Wang, W.L. Xia, X.Q. Yan, K. Zhu
PKU, Beijing, People's Republic of China
W.P. Dou, Y. He
IMP, Lanzhou, People's Republic of China

Funding: This work is supported by the 973 program (No. 2014CB845503) and the NSFC (Grants No. 11079001).
The beam dynamic design of a 100 mA, 162.5 MHz Radio Frequency Quadrupole (RFQ) is presented in this paper. The RFQ will accelerate protons from 85 keV to 3 MeV under the operation mode of continuous-wave (CW). The code PARMTEQM is used to carry out the beam dynamics design and the transmission efficiency has been optimized and improved to more than 99%. In the design of this high-current linac, the space charge effect is analyzed as it can cause emittance growth, nonuniform particle density distribution and resonance effect. The electrode structure parameters generated by PARMTEQM also be adopted by the code of Toutatis to verify the result’s veracity.

TUPP004

An In-flight Radioactive Ion Separator Design for the ATLAS Facility

dipole, ion, target, simulation

446

B. Mustapha, B. Back, C.R. Hoffman, B.P. Kay, J.A. Nolen, P.N. Ostroumov
ANL, Argonne, USA

Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357.
An in-flight radioactive beam separator, named AIRIS, is being designed to enhance the radioactive beam capabilities of the ATLAS facility at Argonne. In order to serve all the experimental areas while maintaining the stable beam capabilities, the separator design is of broadband type. This design allows the selected radioactive beam to come back on the ATLAS beam line while stable beams continue on the same straight line with the separator turned off. The separation is performed in two steps, the first is magnetic in a chicane made of four magnets and four multipoles, while the second uses an rf sweeper taking advantage of the time separation between the beam of interest and potential contaminants including the primary beam tail. We will report on the progress of the AIRIS design effort with special emphasis on the performance of the rf sweeper.

TUPP019

Qualification of the Titanium Welds in the E-XFEL Cryomodule and the CE Certification

cryomodule, cavity, operation, linac

468

S. Barbanotti, H. Hintz, K. Jensch, R. Klos, W. Maschmann, A. Matheisen, A. Schmidt
DESY, Hamburg, Germany
C. Boulch, C. Cloué, C. Madec, J.L. Perrin, T. Trublet
CEA/IRFU, Gif-sur-Yvette, France
J.-P. Charrier, O. Napoly
CEA/DSM/IRFU, France

The CE stamping of the one hundred 1.3 GHz cryomodules for the XFEL Linac is a main step in the process of the certification of the entire Linac as a pressure equipment. Stringent requirements on materials and the quality of the welds of the pressurised components need to be satisfied to obtain the stamp. This paper summarizes these requirements, describes the process developed to qualify each module and summarises the rework campaign on the cavity helium vessels made necessary to obtain the required quality for a reliable and safe accelerator.

TUPP025

Progress on ESS Medium Energy Beam Transport

linac, rfq, cavity, DTL

484

I. Bustinduy, D. Fernandez-Cañoto, N. Garmendia, A. Ghiglino, O. González, P.J. González, Z. Izaola, I. Madariaga, M. Magan, L. Muguira, J.L. Muñoz, I. Rueda, F. Sordo, S. Varnasseri, R. Vivanco
ESS Bilbao, Bilbao, Spain
M. Eshraqi, R. Miyamoto, A. Ponton
ESS, Lund, Sweden

The considered versatile ESS MEBT is being designed to achieve four main goals: First, to contain a fast chopper and its correspondent beam dump, that could serve in the commissioning as well as in the ramp up phases. A detailed study of the chopper rise time effects on the loss budget will be presented. Second, to serve as a halo scraping section by means of various adjustable blades. Third, to measure the beam phase and proﬁle between the RFQ and the DTL, along with other beam monitors. And ﬁnally, to match the RFQ output beam characteristics to the DTL input both transversally and longitudinally. For this purpose a set of eleven quadrupoles is used to match the beam characteristics transversally, combined with three 352.2 MHz CCL type buncher cavities, which are used to adjust the beam in order to fulfil the required longitudinal parameters. A thorough study on the optimal input beam parameters will be discussed. Quadrupole design update will be presented along with new RF measurements over the buncher prototype. Finally, updated results will be presented on the chopper and beam-dump system.

Poster TUPP025 [5.596 MB]

TUPP037

Transverse Emittance Measurements of the REX-ISOLDE Beams in Preparation for the HIE-ISOLDE Commissioning

emittance, linac, background, ion

513

D. Voulot, M.A. Fraser, D. Lanaia
CERN, Geneva, Switzerland
T. Olsson
MAX-lab, Lund, Sweden

The transverse emittance at the output of the REX-ISOLDE normal conducting linac has been measured at different energies in order to characterise the beam at injection to the future HIE-ISOLDE superconducting linac. The measurements were done with low intensity stable beams (~0.5 enA) in order to avoid compensation effects in the EBIS ion source and obtain representative measurements of the radioactive ion beam emittance. Emittances were measured using a slit-grid emittance meter and compared with results obtained with a quadrupole-scan (three-gradient) method. An analysis of the background suppression is presented and possible source of errors for both type of measurements are discussed.

Poster TUPP037 [2.084 MB]

TUPP038

Transverse Beam Profile Measurements in the Linac4 Medium Energy Beam Transport

emittance, simulation, linac, rfq

516

M. Yarmohammadi Satri, G. Bellodi, V.A. Dimov, J.-B. Lallement, A.M. Lombardi, U. Raich, F. Roncarolo, F. Zocca
CERN, Geneva, Switzerland

Linac4 is a 160 MeV H⁻ linear accelerator presently under construction at CERN. It will replace the present 50 MeV proton Linac2 as injector of the proton accelerator complex as part of a project to increase the LHC luminosity. The Linac4 front-end, composed of a 45 keV ion source, a Low Energy Beam Transport (LEBT), a 352.2 MHz Radio Frequency Quadrupole (RFQ) which accelerates the beam to 3 MeV and a Medium Energy Beam Transport (MEBT) housing a beam chopper, has been commissioned in the Linac4 tunnel. The MEBT is composed of three buncher cavities and 11 quadrupole magnets to match the beam from the RFQ to the next accelerating structure (DTL) and it includes two wire scanners for beam profile measurement. In this paper we present the results of the profile measurements and we compare them with emittance measurements taken with a temporary slit-and-grid emittance measurement device located after the MEBT line.

TUPP039

Accuracy Determination of the ESS MEBT Emittance Measurements

emittance, scattering, proton, linac

519

B. Cheymol, A. Ponton
ESS, Lund, Sweden

The European Spallation Source MEBT will be equipped with a full set of diagnostics in order to characterize the bean properties before the injection in the DTL. The 6D phase space of the beam shall be characterize during the commissioning of the normal conducting as well as on regular basis during retuning phase of the machine. In this paper we will discuss the accuracy of the transverse emittance measurement that will be performed with the slit-grid method. The slit geometric parameters have been determined in order to achieve the required resolution and sensitivity. Scattering effects at the slit have been considered to determine the emittance measurement accuracy.

TUPP047

PXIE RFQ Bead Pull Measurements

rfq, beam-transport, cavity, experiment

535

P. Berrutti, T.N. Khabiboulline, V. Poloubotko, G.V. Romanov, J. Steimel, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA
D. Li, J.W. Staples
LBNL, Berkeley, California, USA

Funding: Work supported by D.O.E. Contract No. DE-AC02-07CH11359
Project X Injector Experiment radio frequency quadrupole has recently been built for Fermilab by Berkley laboratory. This RFQ will be placed after the low energy beam transport (LEBT) and before the medium energy beam transport (MEBT). The RFQ will operate at 162.5 MHz in CW regime; its function is to accelerate and focus particles coming from the LEBT at 30 keV, and to deliver a beam at 2.1 MeV to the MEBT. In order to make sure that the RFQ meets the specifications of field flatness and frequency the field in the vanes should be measured using bead pull technique. FNAL created a new single wire bead pull set up for the RFQ of PXIE. The measurements are used to find the electrical center of the structure, then the amplitude of the electromagnetic field in all the sectors of the RFQ; and the tuning will be based on these measurements. This paper describes the bead pull experimental set up, the software developed for this particular application and the measurements taken.

Poster TUPP047 [1.089 MB]

TUPP054

Study of Beam-Based Alignment for the LCLS-II SC Linac

linac, emittance, alignment, cryomodule

544

A. Saini, N. Solyak, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA
T.O. Raubenheimer
SLAC, Menlo Park, California, USA

The Linac Coherent Light Source (LCLS) is an x-ray free electron laser facility. The proposed upgrade of the LCLS facility is based on construction of 4 GeV superconducting (SC) linac. The achievable performance of linac is determined by beam sensitivity to various component errors. In this paper we review misalignment tolerances of LCLS-II SC linac and discuss possible beam-based alignment algorithm to meet these tolerances.

TUPP057

In Situ Measurement of Mechanical Vibrations of a 4-Rod RFQ at GSI

laser, rfq, operation, vacuum

553

P. Gerhard, L. Groening, K.-O. Voss
GSI, Darmstadt, Germany

A new 4-rod CW Radio Frequency Quadrupole was commissioned at the high charge state injector HLI at the UNILAC in 2009. It is in operation since 2010*. At high rf amplitudes strong modulations of the rf reflection emerge, with a modulation frequency of approximately 500 Hz. They are attributed to mechanical oscillations of the rods, excited by the rf pulse. The high fraction of reflected rf power severely limits the pulse length and rf amplitude achievable. As these modulations could only be seen during the rf pulse by means of rf measurements, a direct observation of the mechanical vibrations was desirable. Such measurements have been conducted using a commercial laser vibrometer, allowing for the investigation of the mechanical behavior of the RFQ independent of the presence of rf power. After a short introduction of the method, the results will be presented and compared with rf measurements and simulations.
*: P. Gerhard et al., “Experience with a 4–Rod CW RFQ”, LINAC’12, Sept. 2012, Tel Aviv, THPB035

TUPP059

Advanced Beam Matching to a High Current RFQ

rfq, simulation, emittance, ion

559

S.G. Yaramyshev, W.A. Barth, L.A. Dahl, P. Gerhard, L. Groening, M.T. Maier, S. Mickat, A. Orzhekhovskaya, B. Schlitt, H. Vormann
GSI, Darmstadt, Germany

The High Current Injector (HSI) of the heavy ion linac UNILAC at GSI comprises the transport lines, the RFQ and two DTL tanks. Beam matching to the RFQ acceptance with a magnetic quadrupole quartet has been worked out manually during commissioning and operation of the machine. Due to a strong overlapping of the field from neighboring quadrupole lenses, a standard optics calculation does not provide for the required reliability. Advanced beam dynamics simulations have been done with the macroparticle code DYNAMION. The superposition of the measured magnetic fields of each quadrupole was taken into account. The quadrupole settings were optimized using the Monte-Carlo method. Two solutions have been found in accordance with the general theory of particle optics. Beam dynamics simulations with new quadrupole settings show an increased particle transmission through the RFQ. The results of numerical study have been confirmed during experimental campaigns. An improved performance of the whole HSI has been demonstrated. The proposed algorithm and a comparison of the measured data with result of simulations are presented.

TUPP062

A Rebunching CH Cavity for Intense Proton Beams

linac, multipole, cavity, simulation

566

M. Schwarz, C. Claessens, M. Heilmann, O. Hinrichs, D. Koser, O. Meusel, D. Mäder, H. Podlech, U. Ratzinger, A. Seibel
IAP, Frankfurt am Main, Germany

Funding: Project supported by the EU, FP7 MAX, Contract No. 269565
The Frankfurt Neutron Source at the Stern-Gerlach-Zentrum (FRANZ) will provide ultra short neutron pulses at high intensities and repetition rates. The facility is currently under construction at the Goethe-University in Frankfurt am Main (Germany). A 5-Gap CH rebuncher is installed behind a coupled RFQ/IH-DTL combination at the end of the LINAC section between two magnetic quadrupole triplets. It will be used for varying the final proton energy as well as for focusing the bunch longitudinally to compensate huge space charge forces at currents up to 200 mA at the final stage of extension. High current beam dynamic simulations have been performed. They include benchmarking of different beam dynamic codes like LORASR and TraceWin, as well as validating the results by measurements. Detailed examination of multipole field impact, due to the cavity’s geometry, together with error tolerance studies and thermal simulations are also performed. Furthermore, this CH rebuncher serves as a prototype for rt CH cavities at MYRRHA (Belgium), an Accelerator Driven System for transmutation of high level nuclear waste. After copper plating the cavity, RF conditioning will start soon.

Poster TUPP062 [6.015 MB]

TUPP063

Improvements of the LORASR Code and their Impact on Current Beam Dynamics Designs

linac, proton, DTL, focusing

569

R. Tiede, D. Mäder, N.F. Petry, H. Podlech, U. Ratzinger, C. Zhang
IAP, Frankfurt am Main, Germany

LORASR is a multi-particle tracking code optimized for the beam dynamics design of ‘Combined Zero Degree Structure (KONUS)’ lattices, which can benefit from an adapted input file structure and code architecture. Recent code developments focused on the implementation of tools for machine error studies and loss profile investigations, including also steering correction strategies. These tools are a stringent necessity for the design of high intensity linacs. Thus, the abilities of the present LORASR release allow performing a manifold of checks and optimizations before finalizing the layouts of KONUS-based or conventional linacs. Two representative examples are the MAX-MYRRHA Injector and the GSI FAIR Facility Proton Linac, both under development with strong participation of IAP, Frankfurt University. This paper presents the status of the LORASR code development with focus on the new features and illustrates the impact on current designs by examples taken from the above-mentioned projects.

TUPP075

The First Beam Recirculation and Beam Tuning in the Compact ERL at KEK

linac, operation, emittance, recirculation

599

S. Sakanaka, M. Adachi, S. Adachi, M. Akemoto, D.A. Arakawa, S. Asaoka, K. Enami, K. Endo, S. Fukuda, T. Furuya, K. Haga, K. Hara, K. Harada, T. Honda, Y. Honda, H. Honma, T. Honma, K. Hosoyama, K. Hozumi, A. Ishii, X. Jin, E. Kako, Y. Kamiya, H. Katagiri, H. Kawata, Y. Kobayashi, Y. Kojima, Y. Kondou, O.A. Konstantinova, T. Kume, T. Matsumoto, H. Matsumura, H. Matsushita, S. Michizono, T. Miura, T. Miyajima, H. Miyauchi, S. Nagahashi, H. Nakai, H. Nakajima, N. Nakamura, K. Nakanishi, K. Nakao, K.N. Nigorikawa, T. Nogami, S. Noguchi, S. Nozawa, T. Obina, T. Ozaki, F. Qiu, H. Sagehashi, H. Sakai, S. Sasaki, K. Satoh, M. Satoh, T. Shidara, M. Shimada, K. Shinoe, T. Shioya, T. Shishido, M. Tadano, T. Tahara, T. Takahashi, R. Takai, H. Takaki, T. Takenaka, Y. Tanimoto, M. Tobiyama, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, K. Watanabe, M. Yamamoto, Y. Yamamoto, Y. Yano, M. Yoshida
KEK, Ibaraki, Japan
E. Cenni
Sokendai, Ibaraki, Japan
R. Hajima, S. Matsuba, R. Nagai, N. Nishimori, M. Sawamura, T. Shizuma
JAEA, Ibaraki-ken, Japan
J.G. Hwang
KNU, Deagu, Republic of Korea
M. Kuriki, Y. Seimiya
HU/AdSM, Higashi-Hiroshima, Japan
A. Valloni
CERN, Geneva, Switzerland

Superconducting(SC)-linac-based light sources, which can produce ultra-brilliant photon beams in CW operation, are attracting worldwide attention. In KEK, we have been conducting R&D efforts towards the energy-recovery-linac(ERL)-based light source* since 2006. To demonstrate the key technologies for the ERL, we constructed the Compact ERL (cERL)** from 2009 to 2013. In the cERL, high-brightness CW electron beams are produced using a 500-kV photocathode DC gun. The beams are accelerated using SC cavities, transported through a recirculation loop, decelerated in the SC cavities, and dumped. In the February of 2014, we succeeded in accelerating and recirculating the CW beams of 4.5 micro-amperes in the cERL; the beams were successfully transported from the gun to the beam dump under energy recovery operation in the main linac. Then, precise tuning of beam optics and diagnostics of beam properties are under way. We report our experience on the beam commissioning, as well as the results of initial measurements of beam properties.
* N. Nakamura, IPAC2012, TUXB02.
** S. Sakanaka et al., IPAC2013, WEPWA015.

TUPP090

Spatially Periodic RF Quadrupole LINAC

focusing, linac, ion, lattice

634

A.S. Plastun, A. Kolomiets
ITEP, Moscow, Russia

Spatially-periodic RF quadrupole structure is proposed as second section of front end of ion linac. It consists of conventional drift tubes and RF quadrupoles. Quadrupoles are 4-vane segments with nonzero electric potential on the longitudinal axis. Thus the accelerating electric field is formed between drift tubes and RF quadrupoles. Moreover accelerating field can be provided even inside the RF quadrupoles. It allows building structures with different focusing lattices and provides high energy gain rate.

Poster TUPP090 [7.706 MB]

TUPP119

Design Studies for Medium and High beta SCRF Cavities for Indian Spallation Neutron Source

cavity, linac, HOM, lattice

699

A.R. Jana, V. Kumar
RRCAT, Indore, India

There is a plan to build a 1 GeV H⁻ linac for the proposed Indian Spallation Neutron Source (ISNS) at Raja Ramanna Centre for Advanced Technology (RRCAT), Indore. The medium and high energy section of the ISNS linac will consist of beta_g=0.61, as well as beta_g = 0.9, 650 MHz, 5-cell superconducting radiofrequency (SCRF) cavities, for which detailed electromagnetic design studies have been performed. During our design study, we have evolved a generalized procedure for the optimization of geometrical parameters of multi-cell SCRF cavities. Studies on higher order modes supported by the cavity and its effect on beam dynamics, as well as on heat load to the cavity have been performed, which constitute an important aspect of the design study. Finally, detailed studies on Lorentz Force Detuning (LFD) have been performed, and design of the cavity has been optimized to minimize the effect due to the LFD. The paper discussed the details of the calculations and the studies that have been performed during the design study.

WEIOA01

Construction and RF Conditioning of the Cell-Coupled Drift Tube Linac (CCDTL) for Linac4 at CERN

linac, vacuum, coupling, cavity

746

A.G. Tribendis, Y.A. Biryuchevsky, E. Kendjebulatov, Ya.G. Kruchkov, E. Rotov, A.A. Zhukov
BINP SB RAS, Novosibirsk, Russia
Y. Cuvet, A. Dallocchio, J.-F. Fuchs, F. Gerigk, J.-M. Giguet, J. Hansen, T. Muranaka, E. Page, B. Riffaud, N. Thaus, M. Tortrat, M. Vretenar, R. Wegner
CERN, Geneva, Switzerland
M.Y. Naumenko
RFNC-VNIITF, Snezhinsk, Chelyabinsk region, Russia

This paper reports on the construction experience of the Linac4 CCDTL, which took place in two Russian institutes in the framework of three ISTC projects in close collaboration with CERN. The tanks were constructed at VNIITF, Snezhinsk, while the drift tubes and supports were made at BINP, Novosibirsk. All structures were then assembled and tuned at BINP before shipment to CERN where the high-power conditioning took place. The tuning principles, quality checks and conditioning results are presented.

Slides WEIOA01 [4.909 MB]

THPP032

Magnetic Characterization of Fast-Pulsed Quadrupole Magnets for Linac4

linac, flattop, power-supply, target

909

S. Kasaei, M.C.L. Buzio, O. Crettiez, V. Della Selva, L. Fiscarelli, J. Garcia Perez, J.-B. Lallement
CERN, Geneva, Switzerland

Linac4, currently being built at CERN, includes 24 quadrupole magnets characterized by narrow apertures and fast excitation cycles which make accurate magnetic measurements challenging. This paper describes the method used for the measurement, which is a combination of techniques based on stretched wire, rotating and fixed search coils. We show how these different instruments can be used in a complementary way to derive information on different aspects of the magnetic behaviour, such as the impact of hysteresis and dynamic eddy current effects. We summarize the results of the series measurement campaign, which include field strength, harmonic components, and the offset and orientation of the magnetic axis. Finally, we discuss the relevance of these measurements as their impact to the operation of the linac.

THPP033

Linac4 Transverse and Longitudinal Emittance Reconstruction in the Presence of Space Charge

emittance, linac, simulation, rfq

913

J.-B. Lallement, G. Bellodi, V.A. Dimov, A.M. Lombardi, M. Yarmohammadi Satri
CERN, Geneva, Switzerland
M. Yarmohammadi Satri
IPM, Tehran, Iran

Linac4 is a pulsed, normal-conducting 160 Mev H⁻ linear accelerator presently under construction at CERN. It will replace the present 50 MeV Linac2 as injector of the proton accelerator complex as part of a project to increase the LHC luminosity. The 3 MeV front end, composed of a 45 keV ion source, a Low Energy Beam transport (LEBT), a 352 MHz Radio Frequency Quadrupole (RFQ) at 3 MeV and Medium Energy Beam Transport (MEBT) housing a beam chopper, and the first Drift Tube Linac (DTL) tank at 12 MeV have been commissioned during the first half of 2014. The transverse and longitudinal emittance reconstruction technique in the presence of space charge, that will be used for the next commissioning stages and permanently during the Linac operation, was successfully tested and validated. The reconstruction method and the results obtained at 3 and 12 MeV are presented in this paper.

THPP035

Deceleration Measurements of an Electron Beam in the CLIC Test Facility 3

electron, lattice, acceleration, linear-collider

920

R.L. Lillestøl, S. Döbert
CERN, Geneva, Switzerland
E. Adli
University of Oslo, Oslo, Norway

The Test Beam Line at the CLIC Test Facility 3 at CERN is a proof-of-principle of the future CLIC decelerators, which will extract a large amount of beam energy for acceleration of the main CLIC beams. The current beamline consists of a FODO lattice with 13 Power Extraction and Transfer Structures (PETS). We discuss beam deceleration measurements of up to 37 %, taking into account effects from the bunch length and the bunch phase. The 12 GHz phase is reproduced based on measurements in a PETS with an uncombined beam. The spectrometer measurements are also compared to predictions based on the beam current and on the produced rf power in the PETS, as well as particle tracking simulations with the Placet code.

THPP040

A Compact High-Frequency RFQ for Medical Applications

rfq, linac, proton, cavity

935

M. Vretenar, A. Dallocchio, V.A. Dimov, M. Garlaschè, A. Grudiev, A.M. Lombardi, S.J. Mathot, E. Montesinos, M.A. Timmins
CERN, Geneva, Switzerland

In the frame of a new program for medical applications, CERN has designed and is presently constructing a compact 750 MHz Radio Frequency Quadrupole to be used as injector for hadron therapy linacs. The RFQ reaches an energy of 5 MeV in only 2 meters; it is divided into four standardized modules of 500 mm, each equipped with 12 tuner ports and one RF input. The inner quadrant radius is 46 mm and the RFQ has an outer diameter of 134 mm; its total weight is only 220 kg. The beam dynamics and RF design have been optimized for reduced length and minimum RF power consumption; construction techniques have been adapted for future industrial production. The multiple RF ports are foreseen for using either 4 solid-state units or 4 IOT’s as RF power sources. Although hadron therapy requires only a low duty cycle, the RFQ has been designed for 5% duty cycle in view of other uses. This extremely compact and economical RFQ design opens several new perspectives for medical applications, in particular for PET isotopes production in hospitals with two coupled high-frequency RFQs reaching 10 MeV and for Technetium production for SPECT tomography with two RFQs followed by a DTL.

THPP042

Error Study on the Normal Conducting ESS Linac

emittance, DTL, linac, rfq

942

R. De Prisco, M. Eshraqi, R. Miyamoto, E. Sargsyan
ESS, Lund, Sweden
A.R. Karlsson
Lund University, Lund, Sweden

One of the preliminary, but important test to evaluate the robustness of the accelerator design is performing the statistical error study by introducing realistic tolerances on the machine components. In this paper the guidelines to define the tolerances and the correction system are summarized in order to validate the design. Firstly statistical studies have been performed in order to define the sensitivity to single errors and to fix the tolerances. Then all errors, within the previous defined tolerances, are applied with the correction system to evaluate the beam quality and to check if the system guarantees a radiologically safe operation.

THPP045

ESS Linac Beam Modes

rfq, linac, emittance, DTL

951

E. Sargsyan, R. Miyamoto
ESS, Lund, Sweden

The ESS Linac will ultimately deliver 5 MW of beam power to the target with a long-pulse structure of 2.86 ms and 14 Hz repetition rate, which is essential for the production of long-wavelength neutrons [1]. Ten different beam power levels are requested for the operation. In order to preserve the required time structure of the beam, different beam power levels will be produced by reducing the beam current in ten regular steps using an iris with an adjustable aperture in the LEBT. Low current and low emittance beams may as well be useful for the beam commissioning of the Linac. This paper describes the generation and the beam dynamics of different beam modes in the ESS Linac.

THPP071

Proposal of a 325 MHz Ladder-RFQ for the FAIR Proton-Linac

rfq, proton, simulation, dipole

1016

M. Schütt, U. Ratzinger
IAP, Frankfurt am Main, Germany
R. M. Brodhage
GSI, Darmstadt, Germany

Funding: BMBF 05P12RFRB9
For the research program with cooled antiprotons at FAIR a dedicated 70 MeV, 70 mA proton injector is required. The first rf accelerator element is a 325 MHz RFQ accelerating from 95 keV to 3.0 MeV. RFQ’s beyond 300 MHz were realized in 4-Vane-type geometry so far. At IAP there is a tradition in 4-Rod-type RFQ development. This type of RFQ is dominating at lower frequencies. Very promising results have been reached with a ladder type-RFQ, which has been investigated during 2013. In comparison with a traditional 4-Rod RFQ approach the geometry is more convenient at high frequencies. We will show most recent 3D simulations of the frequency tuning possibilities and of a whole cavity demonstrating the power of a ladder type RFQ. An RFQ layout for the new FAIR proton injector will be shown. (see also R. Brodhage, U. Ratzinger, A. Almomani, “Design Study of a High Frequency Proton Ladder RFQ” , Proc. of the 2013 IPAC Conference, Shanghai, China, p. 3788.)

THPP087

ESS DTL Design and Drift Tube Prototypes

DTL, linac, coupling, vacuum

1050

F. Grespan, M. Comunian, A. Pisent, M. Poggi, C. R. Roncolato
INFN/LNL, Legnaro (PD), Italy
P. Mereu
INFN-Torino, Torino, Italy

The Drift Tube Linac (DTL) for the ESS accelerator will accelerate protons up to 62.5 mA average pulse current from 3.62 to 90 MeV. The 5 tanks composing the DTL are designed to operate at 352.2 MHz in pulses of 2.86 ms long with a repetition rate of 14 Hz. The accelerating field is around 3.1 MV/m, constant in each tank. Permanent magnet quadrupoles (PMQs) are used as focusing element in a FODO lattice. The empty drift tubes accommodate Electro Magnetic Dipoles (EMDs) and Beam Position Monitors (BPMs) in order to implement beam corrective schemes. A complete set of Drift Tubes is under construction that is BPM, EMD and PMQ types. These prototypes are aimed to validate the design with the involved integration issues of the various components, as well as the overall technological and assembly process. This paper presents the main mechanical choices and the status of the prototyping program of the Drift Tubes.

THPP091

Installation and Performance Check of Beam Monitors for Energy Upgraded J-PARC Linac

linac, operation, cavity, acceleration

1059

A. Miura, K. Hasegawa, H. Oguri, N. Ouchi
JAEA/J-PARC, Tokai-mura, Japan
M. Ikegami
FRIB, East Lansing, Michigan, USA
Y. Liu
KEK/JAEA, Ibaraki-Ken, Japan
T. Maruta
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
T. Miyao
KEK, Ibaraki, Japan

An energy upgrade project has started to achieve the design beam power of 1 MW at the exit of the downstream synchrotron in the J-PARC Linac since 2009. In the upgraded project, a beam energy in the Linac has increased from present 181 MeV to 400 MeV using the additional 21 annular-ring coupled structure (ACS) cavities. The new beam monitors as the beam current monitors, the phase monitors, the beam position monitors, the transverse profile monitors (wire scanner monitors) and the longitudinal profile monitors (bunch shape monitors) for the part where the ACS cavities were installed were designed, fabricated and calibrated. Till the end of November, 2013, all beam monitors were completed to be installed. From the middle of December, we started the beam commissioning to achieve the beam energy as 400 MeV, as well as to confirm the beam monitor functioning. We achieved the 400 MeV beam acceleration at the middle of January, 2014 using newly installed beam monitors. This paper describes the beam monitor installation, calibration and the beam commissioning results of beam monitor functioning.

THPP097

3D Effects in RFQ Accelerators

rfq, simulation, cavity, emittance

1077

S.S. Kurennoy
LANL, Los Alamos, New Mexico, USA

RFQ accelerators are usually designed and modeled with standard codes based on electrostatic approximations. Recent examples show that this approach fails to accurately predict the performance for 4-rod RFQs: 3D RF effects near the vane ends can noticeably influence the beam dynamics. The same applies to any RFQ where the quadrupole symmetry is broken, e.g., 4-vane RFQ with windows. We analyzed two 201.25-MHz 4-rod RFQs – one recently commissioned at FNAL and a new design for LANL – using 3D modeling with CST Studio. In both cases the manufacturer CAD RFQ model was imported into CST. The electromagnetic analysis with MicroWave Studio (MWS) was followed by beam dynamics modeling with Particle Studio (PS). For the LANL RFQ with duty factor up to 15%, a thermal-stress analysis with ANSYS was also performed. The simulation results for FNAL RFQ helped our Fermilab colleagues fix the low output beam energy. The LANL RFQ design was modified after CST simulations indicated insufficient tuning range and incorrect output energy; the modified version satisfies the design requirements.