IPAC2013 - List of Keywords (emittance)

Paper	Title	Other Keywords	Page
MOYAB101	The First Years of LHC Operation for Luminosity Production	luminosity, proton, injection, feedback	6
	M. Lamont CERN, Geneva, Switzerland
	A summary of the first 3 years of LHC operation is presented with a discussion on the performance ramp-up, operation efficiencies and system reliability. The main contributory factors to peak and integrated luminosity performance are outlined.
	Slides MOYAB101 [12.139 MB]

MOPEA004	Beam Lifetime in the ASTRID and ASTRID2 Synchrotron Light Sources: Excitations and Vacuum Dependences	synchrotron, vacuum, ion, electron	67
	J.S. Nielsen, N. Hertel, S.P. Møller ISA, Aarhus, Denmark
	The beam lifetime is a very important parameter for synchrotron light sources without top-up, and sometimes more important than the lowest possible vertical beam emittance. At the ASTRID synchrotron light source, we have for many years routinely applied a phase modulation of the accelerating RF field, together with a vertical excitation of the beam at the first vertical betatron frequency. These two effects increase the beam lifetime from about 3 hours to more than 100 hours at 150 mA. Lifetime measurements as function of modulation and excitation parameters will be presented. Additionally, measurements of the beam lifetime in ASTRID and ASTRID2 as function of vacuum pressure will be presented.

MOPEA007	Study of Lower Emittance Optics Using Multi-Bend-Achromat Lattice at SOLEIL	dipole, optics, lattice, quadrupole	76
	R. Nagaoka, P. Brunelle, X. Gavaldà, M. Klein, A. Loulergue, A. Nadji, L.S. Nadolski, M.-A. Tordeux SOLEIL, Gif-sur-Yvette, France
	In the framework of a future upgrade of the SOLEIL 354 m long and 2.75 GeV storage ring, a series of lattice studies has been launched to aim at reducing by an order of magnitude the current 4 nm.rad horizontal emittance. In this exercise, the main constraint imposed is to leave all the existing 24 straight sections for insertion devices untouched. In the previous study (presented at IPAC 2012), the possibility of using superbends and exploiting their longitudinal dipole field variation was pursued in lowering the emittance, finding solutions with a horizontal emittance in the sub nanometer range. In the present study, the use of MBA (Multi-Bend-Achromat) lattice is explored, which is widely recognized today as the optimal lattice in reaching an ultra-low emittance. The study aims to clarify the adaptability of the MBA and the range of attainable emittance for the SOLEIL ring, in view particularly of the short straight sections existing in half of the original DBA cells in between the dipoles. The possibility of combining the previously obtained superbend solutions with the MBA lattice is also examined.

MOPEA008	A Low-Emittance Lattice for the ESRF	lattice, sextupole, dipole, injection	79
	L. Farvacque, N. Carmignani, J. Chavanne, A. Franchi, G. Le Bec, S.M. Liuzzo, B. Nash, T.P. Perron, P. Raimondi ESRF, Grenoble, France
	In the framework of its upgrade, the ESRF is looking at a new lattice for replacing the present Double Bend Achromat structure. This new lattice must have the same length and periodicity as the present one and keep the beamline source points unchanged. We will describe our design of an 844 m long lattice based on a 7-bend achromat. It is optimized for minimising the operation costs, in particular the wall-plug power, provides a large dynamic aperture allowing off-axis injection with the present ESRF injector, and gives an horizontal emittance of less than 200 pm at 6 GeV, thus considerably improving the brilliance and transverse coherence of the ESRF.

MOPEA009	ESRF Operation and Upgrade Status	undulator, storage-ring, booster, permanent-magnet	82
	J.-L. Revol, J.C. Biasci, J-F. B. Bouteille, F. Ewald, L. Farvacque, A. Franchi, G. Gautier, L. Goirand, M. Hahn, L. Hardy, J. Jacob, J.M. Koch, M.L. Langlois, G. Lebec, J.M. Mercier, T.P. Perron, E. Plouviez, P. Raimondi, K.B. Scheidt, V. Serrière ESRF, Grenoble, France
	The European Synchrotron Radiation Facility (ESRF) is presently midway through the Upgrade Programme Phase I (2009-2015), which concerns its infrastructure, beamlines and X-ray source. This paper reports on the present operation performance of the source, highlighting the more recent developments. In this context, 8 insertion device straight sections have been lengthened from five to six metres; two of them operating with canted undulators. The lattice of one cell has been modified for a further increase to 7 metres allowing the test of a mini beta optics and latter the distribution of cavities. A second cryogenic permanent magnet undulator has been completed, which gives a factor of more than 2 in flux at high energy. The booster klystron-based radio frequency transmitter has been replaced by high power solid state amplifiers. Out of three prototypes of HOM damped cavities working at room temperature which have been received and tested, one has been successfully commissioned with beam. Subsequent to the upgrade of the beam position monitor system, a new orbit feedback has substantially reduced the orbit distortion induced by ID gap motions.

MOPEA017	Electron Cooling of Heavy Ions Interacting with Internal Target at HESR of FAIR	electron, target, ion, scattering	103
	T. Katayama, M. Steck GSI, Darmstadt, Germany R. Maier, D. Prasuhn, H. Stockhorst FZJ, Jülich, Germany
	The High Energy Storage Ring (HESR) is designed and optimized to accumulate and store the anti-proton beam for the internal target experiment. The recent demand of atomic physics has impacted to use the HESR facility also as the storage ring of bare heavy ions. In this concept the bare heavy ions are injected at 740 MeV/u from the Collector Ring where the ions are well stochastically cooled to be matched with HESR ring acceptance. In the HESR the 2 MeV electron cooler is prepared with the maximal electron current of 3 A and the cooling length of 2.7 m. The electron cooling process of typically ²³⁸U⁹²⁺ beam is simulated for the Hydogen and Xe internal target with simultaneous use of barrier voltage to compensate the mean energy loss caused by the interaction with internal target. In the present report the detailed simulation results of 6D phase space obtained by the particle tracking code are precisely discussed.

MOPEA023	Lattice Design for the ILSF Booster Synchrotron	booster, sextupole, damping, quadrupole	121
	E. Ahmadi, H. Ghasem, F. Saeidi ILSF, Tehran, Iran H. Ghasem IPM, Tehran, Iran
	ILSF booster synchrotron is a full energy 3GeV injector with the circumference of 192m will be housed in a separate tunnel from storage ring. In order to keep low the emittance, a theoretical minimum emittance lattice in which the dipoles and quadrupoles have sextupole component has been considered for the booster. In this paper, the lattice concept and main features of the booster will be reported. The variation of emittance and beam size during booster ramping is also investigated. Finally the effect of existed eddy current on the chromaticity and dynamic aperture will be presented.

MOPEA027	New Optics with Emittance Reduction at the SPring-8 Storage Ring	optics, photon, injection, sextupole	133
	Y. Shimosaki, K. Fukami, K.K. Kaneki, K. Kobayashi, M. Masaki, C. Mitsuda, T. Nakamura, T. Nakanishi, H. Ohkuma, M. Oishi, M. Shoji, K. Soutome, S. Takano, M. Takao JASRI/SPring-8, Hyogo-ken, Japan
	The machine tuning of a new optics is in progress at the SPring-8 storage ring, in order not only to provide brilliant photons for current users but also to study a strategy of a lattice design and a tuning scenario for the upgrade project SPring-8 II. The natural emittance is reduced to 2.4 nmrad from the present value of 3.4 nmrad without any change of magnet positions. The flux density 1.3 times higher than the present was observed at the diagnostics beamline. The nominal injection efficiency of the order of 80 % has been achieved (the present: 92 %) by correcting the error of the optics function, by adjusting the strength of the injection magnets and by optimizing the sextupole magnetic fields. The beam lifetime was 13 h at 1 mA / bunch (the present: 22 h), and the momentum aperture estimated from the measurement of the Touschek lifetime was 2.3 % (the present: 2.8 %). Though these are tolerable to the user operation, further optimization of the sextupoles is ongoing. After verifying the photon beam performance at beamlines, this new optics will be applied to the user operation. The optics design and its beam performance will be presented in detail.

MOPEA032	Installation Status of Deuteron Injector of IFMIF Prototype Accelerator in Japan	neutron, rfq, alignment, simulation	148
	H. Shidara, J. Knaster IFMIF/EVEDA, Rokkasho, Japan D. Bogard, N. Chauvin, P. Girardot, R. Gobin, F. Harrault, D. Loiseau, P.A.P. Nghiem, A. Roger, F. Senée CEA/DSM/IRFU, France L. Semeraro F4E, Barcelona, Spain
	The International Fusion Materials Irradiation Facility (IFMIF) will generate a neutron irradiation field with the spectrum simulating the fusion D-T neutrons (14 MeV) to qualify suitable materials for fusion power plants. The IFMIF accelerator facility provides two CW / 40 MeV / 125 mA deuteron beams to the IFMIF Lithium target facility. In the Engineering Validation and Engineering Design Activities phase, the concept of IFMIF is validated with a single CW / 9 MeV / 125 mA deuteron accelerator prototype under construction in JAEA/Rokkasho. The injector part has been designed, constructed and successfully tested by CEA/Saclay. The ECR ion source produces a deuteron beam of 140 mA at 100 keV. In spring 2013, the injector will be delivered and re-installed on the Rokkasho site. This paper will focus on the detailed plan of the injector’s re-assembly as well as on the re-commissioning. Further possible improvements are discussed in order to achieve reliable operation.

MOPEA042	Research on the Design and Simulation of the CSRE Stochastic Cooling System	sextupole, pick-up, target, simulation	169
	X.J. Hu, H. Jia, Y.J. Yuan, X.H. Zhang IMP, Lanzhou, People's Republic of China
	Stochastic cooling by the use of a feedback system, aims at cooling of secondary particles or particles with large emittance or momentum spread. My research is mainly on the simulation of horizontal and longitudinal stochastic cooling process. The purpose of my work is to obtain the optimum parameters for stochastic cooling, according the actual accelerator lattice. Pickup and preamplifier are already installed on the CSRe, and preliminary results are get.

MOPEA045	Performance Optimization and Upgrade of the SSRF Storage Ring	storage-ring, optics, injection, cavity	178
	Z.T. Zhao, B.C. Jiang, Y.B. Leng, S.Q. Tian, L. Yin, W.Z. Zhang SINAP, Shanghai, People's Republic of China
	The SSRF storage ring achieved its design performance goal in 2008, in the following years its performance was optimized and improved, including implementing top-up operation and low emittance lattice configuration as well as other attempts like fast orbit feedback and low alpha mode. In order to meet the requirements of accommodating more beamlines and high demanding performance in its phase-II beamline project, the SSRF storage ring is being upgraded with a design based on superbend based lattice and a third harmonic RF cavity system. This paper presents the main optimization works and the upgrade design considerations on the SSRF storage ring performance.

MOPEA057	Studies of the Electron Beam Lifetime at MAX III	scattering, cavity, electron, vacuum	208
	A. Hansson, Å. Andersson, J. Breunlin, G. Skripka, E.J. Wallén MAX-lab, Lund, Sweden
	MAX III is a 700 MeV 3rd generation synchrotron light source located at the MAX IV Laboratory in Sweden. The lifetime in the storage ring is lower than originally envisaged. From vertical scraper measurements the lifetime contributions at 300 mA stored current have been determined. The lifetime is mainly limited by the Touschek lifetime, which is lower than its design value, whereas the vacuum lifetime is close to the expected value. The low Touschek lifetime is explained by a lower than design emittance ratio and momentum acceptance in the storage ring.

MOPEA060	Design of Low Momentum Compaction Lattices for the TPS Storage Ring	lattice, sextupole, injection, dipole	217
	C.-C. Kuo, H.-J. Tsai NSRRC, Hsinchu, Taiwan
	The nominal bunch length is around 10 ps rms in the Taiwan Photon Source (TPS), which is currently under construction. To further reduce bunch length to a few ps rms range, low momentum compaction factor configurations (low alpha), i.e., quasi-isochronous machines, are designed. The beam dynamics issues of the TPS low alpha lattices are reported.

MOPEA066	Investigation and Test of the Possibility of Reducing the Emittance of the Diamond Storage Ring	optics, lattice, wiggler, injection	234
	B. Singh, M. Apollonio, R. Bartolini, E.C. Longhi Diamond, Oxfordshire, United Kingdom R. Bartolini, T. Pulampong JAI, Oxford, United Kingdom
	Theoretical and experimental studies have been carried out at the Diamond Light Source to assess the possibility of reducing the emittance of the existing storage ring by means of a change to the optics. The optics solutions obtained so far using a Multi Objective Genetic Algorithm (MOGA) increase the dispersion and the horizontal beta function in the straight section. While the emittance can be reduced to 2.1 nm this optics is limited by the operation of high field superconducting wiggler devices. In this report we present details of the new optics and present results of practical tests. We also compare the theoretical emittance growth due to a wiggler in a dispersive region with test results.

MOPEA067	Ultra-low Emittance Upgrade Options for Third Generation Light Sources	lattice, dipole, resonance, dynamic-aperture	237
	R. Bartolini Diamond, Oxfordshire, United Kingdom T. Pulampong JAI, Oxford, United Kingdom
	The increasing efforts in the synchrotron light sources community toward the design of a diffraction limited source at multi-keV photon energy have eventually stimulated the existing facilities to investigate possible upgrade paths to higher photon brightness and lower emittances to maintain their competitiveness within the users’ community. We present a possible option for upgrading 3rd generation light sources based on a rebiuld of the arcs with MBA cells, using diamond as an example. Emphasis is given to the AP desing issues with a view to minimal changes to the machine layout, contained cost and minimal downtime

MOPEA071	Operating the Diamond Storage Ring with Reduced Vertical Emittance	feedback, coupling, target, storage-ring	249
	I.P.S. Martin, M.G. Abbott, M. Apollonio, R. Bartolini, D. Hickin Diamond, Oxfordshire, United Kingdom R. Bartolini JAI, Oxford, United Kingdom
	In a synchrotron radiation light source, a reduction in vertical emittance can potentially increase the source brightness, reduce the spot size for microfocus beam lines or increase the vertical transverse coherence of the photon beam. With this aim, the target vertical emittance for the Diamond storage ring has been recently reduced from 27pm.rad to 8pm.rad (0.3% coupling). In this paper we discuss the main impacts of this reduction, along with the steps that have been taken to stabilise the coupling at the new value.

MOPEA072	Recent Improvement of the APS Booster Synchrotron	booster, lattice, injection, synchrotron	252
	C. Yao, R. Laird, V. Sajaev, N. Sereno, H. Shang, J. Wang, S. Xu ANL, Argonne, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-ACO2-O6CH11357. The APS booster injector is a 7-GeV electron synchrotron. Several improvements have been implemented in the booster area, including the development of the 92-nm low emittance lattice, upgrading the ramp current readback ADC, and development of a new firing card for the main ramp supplies. Recently we have completed the commissioning of the low emittance lattice and it is now APS operational lattice. Combined with improvement in the optimization in the storage ring lattice and injection, we have achieved close to 100% storage ring injection efficiency. This report presents the improvements and measured beam parameters and the measured performance of the ramp control.

MOPEA074	Lattice Studies for a Potential Soft X-ray Diffraction Limited Upgrade of the ALS	lattice, brightness, scattering, injection	258
	C. Steier, J.M. Byrd, R.W. Falcone, S.D. Kevan, D. Robin, C. Sun, H. Tarawneh, W. Wan LBNL, Berkeley, California, USA
	Funding: The Advanced Light Source is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. The Advanced Light Source (ALS) at Berkeley Lab has seen many upgrades over the years, keeping it one of the brightest sources for soft x-rays worldwide. Recent developments in magnet technology and lattice design (multi bend achromat lattices) appear to open the door for very large further increases in brightness, particularly by reducing the horizontal emittance, even within the space constraints of the existing tunnel. Initial studies yielded candidate lattices which approach the soft x-ray diffraction limit (around 2 keV) in both planes within the ALS footprint.

MOPEA075	Completion of the Brightness Upgrade of the ALS	lattice, brightness, insertion, sextupole	261
	C. Steier, B.J. Bailey, K. Berg, A. Biocca, A.T. Black, P.W. Casey, D. Colomb, R.F. Gunion, N. Li, A. Madur, S. Marks, H. Nishimura, G.C. Pappas, K.V. Petermann, G.J. Portmann, S. Prestemon, A.W. Rawlins, D. Robin, S.L. Rossi, T. Scarvie, D. Schlueter, C. Sun, H. Tarawneh, W. Wan, E.C. Williams LBNL, Berkeley, California, USA C. Chen, J. Jin, Y.M. Wen, J. Wu, L. Yin, J.D. Zhang, Q.G. Zhou SINAP, Shanghai, People's Republic of China
	Funding: The Advanced Light Source is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. The Advanced Light Source (ALS) at Berkeley Lab remains one of the brightest sources for soft x-rays worldwide. A multiyear upgrade of the ALS is underway, which includes new and replacement x-ray beamlines, a replacement of many of the original insertion devices and many upgrades to the accelerator. The accelerator upgrade that affects the ALS performance most directly is the ALS brightness upgrade, which reduced the horizontal emittance from 6.3 to 2.0 nm (2.5 nm effective). Magnets for this upgrade were installed starting in 2012 followed by a transition to user operations with 2.0 nm emittance in spring 2013.

MOPEA079	Improving Emittances in Existing Storage Rings by Defocusing Dipoles	dipole, quadrupole, optics, lattice	270
	C.E. Mayes, L. Gupta, G.H. Hoffstaetter, V.O. Kostroun, A.A. Mikhailichenko CLASSE, Ithaca, New York, USA
	Designs for ultimate storage rings typically employ two strategies to lower the emittances: 1) adding more bending magnets, and 2) using only focusing quadrupole magnets, with additional defocusing in the bending magnets. In an existing storage ring, the first strategy is precluded because the number of bends is typically fixed, but the second strategy could be used at modest expense. With the CESR storage ring as an example, we show how this is possible and propose an optics that reduces its emittance by more than a factor of 20. Furthermore, such an upgrade would could be installed incrementally without any long dark-time period.

MOPFI002	Results from Beam Commissioning of an SRF Plug-gun Cavity Photoinjector	cavity, laser, cathode, gun	282
	M. Schmeißer, R. Barday, A. Burrill, A. Jankowiak, T. Kamps, J. Knobloch, O. Kugeler, P. Lauinger, A. Neumann, J. Völker HZB, Berlin, Germany P. Kneisel JLAB, Newport News, Virginia, USA R. Nietubyć NCBJ, Świerk/Otwock, Poland J.K. Sekutowicz DESY, Hamburg, Germany I. Will MBI, Berlin, Germany
	Superconducting rf photoelectron injectors (SRF guns) hold the promise to deliver high brightness, high average current electron beam for future lightsources or other applications demanding continuous wave operation of an electron injector. This paper discusses results from beam commissioning of a hybrid Pb coated plug-gun Nb cavity based SRF photoinjector for beam energies up to 3 MeV at Helmholtz-Zentrum Berlin. Emittance measurements and transverse phase space characterization with solenoid-scan and pepperpot methods will be presented.

MOPFI004	The Injector Layout of BERLinPro	cathode, linac, cavity, gun	288
	B.C. Kuske, M. Abo-Bakr, V. Dürr, A. Jankowiak, T. Kamps, J. Knobloch, P. Kuske, S. Wesch HZB, Berlin, Germany
	Funding: The Bundesministerium für Bildung und Forschung (BMBF) and the state of Berlin, Germany. BERLinPro is an Energy Recovery Linac Project running since 2011 at the HZB in Berlin. The key component of the project is the 100mA superconducting RF photocathode gun under development at the HZB since 2010. Starting in 2016 the injector will go into operation providing 6 MeV electrons with an emittance well below 1mm mrad and bunches shorter than 4ps. 2017 the 50MeV linac will be set up and full recirculation is planned for 2018. The injector design including a dogleg merger has been finalized and is described in detail in this paper. Emphasis is laid on the final layout including collimators and diagnostics and performance simulations of two different gun cavities and first tolerance studies.

MOPFI012	Measurement of Adsorption Rates of Residual Gases for NEA-GaAs Surface	electron, cathode, ion, vacuum	306
	M. Kuriki, H. Iijima, K. Miyoshi, K.U. Uchida HU/AdSM, Higashi-Hiroshima, Japan
	A GaAs photocathode activated the surface to negative-electron-affinity (NEA) is an important device for high-average-current electron accelerators such as a next-generation light source based on an energy recovery linac. The NEA surface is normally formed by a yo-yo technique in which cesium and oxygen are applied onto the surface alternately. Although the initial quantum efficiency is relatively larger than that of another cathode, the lifetime is shorter. The degradation with time elapsing even if the electron beam is not extracted is mainly caused by adsorption of residual gases in a vacuum chamber. We have evaluated the adsorption rates of various gases for the NEA surface by measuring the dark lifetime in sample gases such as hydrogen, carbon oxide and carbon dioxide.

MOPFI033	Commissioning Results and Progress of a Helium Injector for Coupled RFQ and SFRFQ Project at Peking University	ion, rfq, ion-source, cavity	357
	J. Chen, J.E. Chen, S.L. Gao, Z.Y. Guo, Y.T. Luo, S.X. Peng, H.T. Ren, Z. Wang, Z.H. Wang, W.L. Xia, Y. Xu, A.L. Zhang, T. Zhang, J. Zhao PKU, Beijing, People's Republic of China
	At Peking University (PKU) a new helium injector for coupled radio frequency quadrupole(RFQ) and separated function radio frequency quadrupole(SFRFQ) within one cavity, so called as coupled RFQ & SFRFQ, was designed recently. It will provide a 30keV 20mA He⁺ beam whose emittance is less than 0.15 π.mm.mrad for the accelerator. It is a combination of a 2.45GHz PKU PMECRIS (Permanent Magnet ECRIS) and a 1.16 m long LEBT. Within the 1.16 m LEBT, 2 solenoids, 2 steering magnets, a kicker, a space charge compensation section, a collimator, two vacuum valves, a Faraday cup and an ACCT are installed. The manufacture has been completed and the commissioning is on the way. In this paper we will address the commissioning results and its progress. Haitao Ren, et al., A Helium Injector for Coupled RFQ and SFRFQ Cavity Project at Peking University. Proc. LINAC’12, Paper TUPB034, Israel, 2012

MOPFI036	Study of the Cold Cathode RF Electron Gun Based on Doped Diamond Films at CAEP	gun, cathode, electron, FEL	366
	X. Li TUB, Beijing, People's Republic of China W. Bai, M. Li CAEP/IAE, Mianyang, Sichuan, People's Republic of China
	Diamond relevant materials have been considered as a promising field emission cathode in recent years. High current density can be obtained either by diamond field emission arrays or by doped diamond films under electrical strengths of several decades of MV/m. Based on the doped films a half cell S-band electron gun has been designed and constructed at CAEP. The gun can provide an accelerating gradient of 60-80 MV/m on the cathode surface (6 mm in diameter). Simulations have proven good performance of such a gun but it needs confirmed by further experiments. Details of the experiments and comparisons with simulations will be reported.

MOPFI037	Design and Experiment of a Compact C-band Photocathode RF Gun for UED	gun, solenoid, cathode, electron	369
	X.H. Liu, H.B. Chen, W.-H. Huang, C.-X. Tang, Z. Zhang TUB, Beijing, People's Republic of China
	A compact C-band photocathode RF gun for the MeV UED facility is developed in Tsinghua University, which is designed to work at the frequency of 5.712GHz. This paper presents the physics and RF structure design, and beam dynamics optimization of this C-band RF gun. Some new structure design will be adopted in this gun, including the optimized cavity length and elliptical iris, which is helpful to achieve lower emittance and larger mode separation. This paper likewise presents experiment parameters and the cold test results of this C-band RF gun.

MOPFI038	Generation and Measurement of Sub-picosecond Electron Bunch in Photocathode RF Gun	laser, electron, radiation, acceleration	372
	W.W. Li, Z.G. He, R. Huang, Q.K. Jia, G. Zhou USTC/NSRL, Hefei, Anhui, People's Republic of China
	The generation of subpicosecond electron bunch in the photocathode rf gun was considered and simulated by improving the acceleration gradient of the gun, suitably tuning the charge of the electron bunch and the acceleration phase. To measure the length of the electron bunch, the design of a nondestructive bunch length measurement technology was also presented in this paper.

MOPFI039	The Design of a Compact THz Source Based on Photocathode RF Gun	electron, radiation, gun, space-charge	375
	W.W. Li, Z.G. He, R. Huang, Q.K. Jia USTC/NSRL, Hefei, Anhui, People's Republic of China
	Narrow-band THz coherent Cherenkov radiation can be driven by a subpicosecond electron bunch traveling along the axis of a hollow cylindrical dielectric-lined waveguide. We present a scheme of compact THz radiation source based on the photocathode rf gun. On the basis of our analytic result, the subpicosecond electron bunch with high charge (800pC) can be generated directly in the photocathode rf gun. A narrow emission spectrum peaked at 0.24 THz with 2 megawatt (MW) peak power is expected to gain in the proposed scheme (the length of the facility is about 1.2 m), according to the analytical and simulated results.

MOPFI054	Upgrades for the CERN PSB-TO-PS Transfer at 2 GeV	injection, optics, kicker, quadrupole	404
	W. Bartmann, J. Borburgh, J.R.T. Cole, S.S. Gilardoni, B. Goddard, O. Hans, M. Hourican, L. Sermeus, R. Steerenberg CERN, Geneva, Switzerland C.H. Yu IHEP, Beijing, People's Republic of China
	The CERN PS Booster extraction energy will be upgraded from 1.4 to 2.0 GeV to alleviate the direct space charge tune shift in the PS. The focussing structure of the transfer line will be modified in order to better match the optics between the PSB and the PS. The optics of the PS at injection and, with it, of the transfer line can be adapted to reduce the continuous losses from the already injected and circulating beam bumped towards the septum. Experimental results of the optics optimisation and probing the injection kicker gap will be shown.

MOPFI059	Design and Performance of the Beam Transfer Lines for the HIE-ISOLDE Project	target, simulation, optics, dipole	416
	A.S. Parfenova, W. Andreazza, J. Bauche, E.D. Cantero, P. Farantatos, M.A. Fraser, B. Goddard, Y. Kadi, A.J. Kolehmainen, D. Lanaia, M. Martino, R. Mompo, E. Siesling, A.G. Sosa, M.A. Timmins, G. Vandoni, D. Voulot, E.S. Zografos CERN, Geneva, Switzerland
	Beam design and beam optics studies for the HIE-ISOLDE transfer lines have been carried out in MadX, and benchmarked against Trace3D results. Magnet field errors and alignment imperfections leading to deviations from design parameters have been treated explicitly, and the sensitivity of the machine's lattice to different individual error sources was studied. As a result, the tolerances for the various error-contributions have been specified for the different equipment systems. The design choices for the expected magnet field and power supply quality, alignment tolerances, instrument resolution and physical aperture were validated. The methodology and results of the studies are presented.

MOPFI062	Optimization Studies for the SwissFEL RF-Gun	gun, cathode, laser, solenoid	425
	M. Schaer, A. Adelmann, A. Anghel, S. Bettoni, P. Craievich, L. Stingelin, C. Vicario, R. Zennaro PSI, Villigen PSI, Switzerland Z. Zhang TUB, Beijing, People's Republic of China
	The 250 MeV SwissFEL injector test facility is in operation since August 2010. Measurements with the "CTF2 Gun 5" photocathode S-band rf-gun show promising beam parameters and satisfy the requirements of the SwissFEL project. Since the performance of the electron source is fundamental for the stability and brightness of a free electron laser, further gun optimization studies are pursued. Under investigation is currently a 3.6 cell C-band gun. First ASTRA simulations indicate that with this gun the peak-current can be increased, thanks to a shorter laser pulse and a higher initial acceleration, by almost a factor of two, at slightly better emittance values than the S-band "PSI Gun 1". Since the beam-quality depends also on the achieved performance of the cathode, several copper cathodes had been tested in the SwissFEL injector test facility to analyze the observed rapid degradation of quantum efficiency.

MOPFI074	Ultracold and High Brightness Electron Source for Next Generation Particle Accelerators	electron, laser, plasma, brightness	452
	G.X. Xia, R. Appleby, W. Bertsche, M.A. Harvey UMAN, Manchester, United Kingdom S. Chattopadhyay STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom S. Chattopadhyay Cockcroft Institute, Warrington, Cheshire, United Kingdom A.J. Murray The University of Manchester, The Photon Science Institute, Manchester, United Kingdom
	The ultra-cold plasma-based electron source has recently been proposed as an alternative to the conventional photoemitters or thermionic electron guns, which are widely used in today’s particle accelerators. The advantages of the ultra-cold plasma-based electron source lie in the fact that the electron beam extracted from the cold plasma (from ionization of cold atoms) has very low electron temperature, e.g. down to 10 K, and has the potential for producing high brightness and ultra-short electron bunches. All these features are crucial for the next generation particle accelerators, e.g. free electron lasers, plasma-based accelerators and the future linear colliders. In this paper, we will introduce our proposed facility on cold electron source based at Photon Science Institute (PSI) in the University of Manchester.

MOPFI081	Correlating Structure and Function - In situ X-ray Analysis of High QE Alkali-antimonide Photocathodes	cathode, scattering, controls, vacuum	464
	J. Smedley, K. Attenkofer, S.G. Schubert BNL, Upton, Long Island, New York, USA I. Ben-Zvi, X. Liang, E.M. Muller, M. Ruiz-Osés Stony Brook University, Stony Brook, USA T. Forrest, H.A. Padmore, T. Vecchione, J.J. Wong LBNL, Berkeley, California, USA J. Xie ANL, Argonne, USA
	Funding: The authors wish to acknowledge the support of the US DOE, under Contract No. KC0407-ALSJNT-I0013, DE-AC02-98CH10886 and DE-SC0005713. Use of CHESS is supported by NSF award DMR-0936384. Alkali antimonide photocathodes have high quantum efficiency and low emittance when illuminated by visible light, and are thought to be well suited for use in high-brightness photoinjectors of 4th generation light sources. Here we report on the growth of multi-alkali K2CsSb cathodes on [100] silicon substrates measured using in-situ X-ray diffraction (XRD) and X-ray reflection (XRR). Correlations between cathode structure and growth parameters and the resulting quantum efficiency (QE) are also explored. The best cathodes have a QE at 532 nm in excess of 6% and are structurally textured K2CsSb with grain sizes in excess of 20 nm. In an attempt to reduce the complexity of the current growth methodology we are also making alkali antimonides in parallel via the reaction of bulk materials in an inert environment. This approach has the advantage that the desired stoichiometry can be obtained exactly. Initial diffraction results from prepared bulk materials are promising and show the formation of well reacted K3Sb. In the future we intend to transfer this material to smooth thin photocathode films by either sputtering or pulsed laser deposition.

MOPME020	Development of the New Measurement Method for the Incoherent Tune Spread and the Tune Shift Caused by the Space Charge Effect	dipole, simulation, injection, space-charge	512
	S. Kato Tohoku University, Graduate School of Science, Sendai, Japan H. Harada, H. Hotchi, M. Kinsho, K. Okabe JAEA/J-PARC, Tokai-mura, Japan
	For the high intensity accelerator, the incoherent tune which is the frequency of the individual particles is shifted and decreases due to the space charge effect. In addition, the incoherent tune is formed into spread shape commonly. When the incoherent tune satisfies a resonance condition, it might be occurred the beam emittance growth and the beam loss. So it is necessary to reduce the incoherent tune spread and the tune shift as much as possible. To achieve this condition, it is desired to measure the incoherent tune spread and the tune shift directly. Therefore we are developing the new measurement method of the incoherent tune spread and the shift due to the space charge effect. From the simulation results, it was cleared that the beam distribution can be modified in the case of using the mono frequency dipole exciter because a particle which has the tune corresponding to the exciter can be resonated temporary. In addition, it was cleared that it is possible to evaluate the incoherent tune spread and the tune shift by the measurement of the distribution transition. We present the outline of this method and the developing plane at the J-PARC RCS.

MOPME022	Beam Commissioning of Two Horizontal Pulse Steering Magnets for Changing Injection Painting Area from MLF to MR in the 3-GeV RCS of J-PARC	injection, stripper, beam-transport, target	518
	P.K. Saha, H. Harada, N. Hayashi, H. Hotchi, M. Kinsho, T. Takayanagi, N. Tani JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan Y. Irie KEK, Ibaraki, Japan S. Kato Tohoku University, Graduate School of Science, Sendai, Japan
	We have been successfully commissioned two pulse steering magnets installed in the Linac to 3-GeV RCS (Rapid Cycling Synchrotron) injection beam transport (BT) line of J-PARC. RCS has to deliver a simultaneous as well as specific beam as demand by the downstream facilities of MLF (Material and Life Science Facility) and the MR (Main Ring). In order to obtain relatively a smaller transverse emittance at extraction, those magnets were designed to perform a smaller injection painting for the MR beam as compared to the MLF one. As stripper foil position is fixed for the charge exchange H⁻ injection, inclination of the injected beam centroid on foil for the MR beam is only moved to a smaller value by the pulse steering magnets, while DC septum magnets are fixed as determined first for the MLF beam. Their parameters were found to be very consistent with expectation and thus already in operation for switching to a painting area of 100 pi mm mrad for the MR beam as compared to that of 150 pi mm mrad for the MLF beam.

MOPME031	Emittance Measurement with Multi-wire Scanners for BEPC-II Linac	positron, linac, electron, injection	541
	H. Geng, W.B. Liu, W. Qiao, Q. Qin, Y.F. Sui, Y. Yue IHEP, Beijing, People's Republic of China
	During the BEPC-II linac upgrade, five wire scanners have been installed in the common transport line, which makes a fast emittance measurement possible. In this paper, we will show the primary results of BEPC-II linac emittance measurement using multi-wire scanner method. The least squares method will be used for data analysis. A comparison of the results with the ones obtained by quad scan method will also be given.

MOPME033	Wire Scanner Emittance Measurement and Software Design at BEPCII	linac, target, quadrupole, EPICS	544
	W. Qiao, Z. Duan, H. Geng, W.B. Liu, Y.F. Sui IHEP, Beijing, People's Republic of China
	Wire scanners are diagnostic devices to measure the beam profile. Resent years, BEPCII adopts wire scanner measurement system for accurate beam size and emittance measurements. Beam emittance measurements can be performed with no adverse impact on beam and no interruption to normal machine operation. The BEPCII wire scanner system includes sets of four scanners in linac by which the linac output emittance is determined. In order to make the measurement procedure automated and easily accessible to all operators, wire scanner measurement software is developed. The software can obtain real-time signal data from the Experimental Physics and Industrial Control System(EPICS) and emittance calculation, phase chart and optics envelope display will be done. In this paper we describe the construction, performance and uses of BEPCII wire scanners measurement system and software.

MOPME035	Design of a Non-Intercepting Beam Diagnostic Device Using Neutral Beam Fluorescence Method	neutral-beams, ion, diagnostics, target	547
	J. Zhao, J. Chen, J.E. Chen, Z.Y. Guo, S.X. Peng, H.T. Ren, Y. Xu, A.L. Zhang, T. Zhang PKU, Beijing, People's Republic of China H.W. Zhao IMP, Lanzhou, People's Republic of China
	The forward neutral beam from deflecting magntic field carries some characteristic properties of high intensity particle beams, such as profile, emittance etc. Therefore a reliable measurement of neutral beam fluorescence can be used to develop a fast and non-interceptive beam diagnostic tool. A non-intercepting beam emittance (profile) monitor using neutral beam fluorescence method has being constructed at Peking University. As a performance test, an emttiance of an extracted proton beam from a permanent magnetic electron cyclotron resonance (ECR) ion source was successfully measured. The details of design and results of measurement will be presented in this paper.

MOPME038	A New Theoretical Design of BLM System for HLS II	electron, vacuum, scattering, monitoring	553
	Y.K. Chen, L.J. He, J. Li, W. Li, Y. Li USTC/NSRL, Hefei, Anhui, People's Republic of China
	Beam loss monitoring (BLM) system has been commonly used to detect the vacuum leakage. The existing BLM system for Hefei Light Source (HLS) was built in 2000. It played an important role in analyzing beam loss distribution and regulating the machine operation parameters. Recently, HLS is being upgraded to HLS II. The emittance will be decreased to increase the brilliance of synchrotron radiation. The Touschek lifetime will be much shorter than before, and dominate the total beam lifetime. It is necessary to redesign the BLM system for HLS II. The most important part of this work is to find a better method of monitoring Touschek lifetime by BLM system while keeping its general functions. According to the results of our research, a preliminary theoretical design for the new BLM system is proposed in this paper. This new system will play an important role in the storage ring commissioning, troubleshooting, and beam lifetime studying.

MOPME040	Cavity-based Multi-parameter Beam Diagnostics at HLS	cavity, quadrupole, diagnostics, gun	559
	Q. Luo, B.G. Sun USTC/NSRL, Hefei, Anhui, People's Republic of China
	Funding: Natural Science Foundation of China (11005106) Recent developments of the fourth generation light sources needs precious control of beam parameters, such as beam position, transverse emittance, beam density, bunch length, etc.. Non-destructive on-line beam diagnostic methods are then required. As an example, the cavity beam multi-parameter monitor system designed for the HLS photocathode RF electron gun consists of a beam position monitor, a beam quadrupole moment monitor and a beam density and bunch length monitor. The cavity beam position monitor uses a re-entrant position cavity tuned to TM110 mode as position cavity and cut-through waveguides to suppress the monopole signal. Beam quadrupole moment monitor system consists of a square pill-box quadrupole moment cavity, a cylindrical pill-box reference cavity and a waveguide coupling network. TM0n0 modes of cavity can be used to work out beam density and bunch length simultaneously. To simplify the design and suppress the whole system here, we use the reference cavity of beam position monitor as beam density and bunch length signal pick-up.

MOPME043	Calibration of Beam Position Monitors in the Injector of HLS II	quadrupole, brilliance, coupling, linac	568
	J.Y. Zou, J. Fang, W.B. Li, P. Lu, T.J. Ma, B.G. Sun, Y.L. Yang, Z.R. Zhou USTC/NSRL, Hefei, Anhui, People's Republic of China
	Funding: Supported by the National Science Foundation of China (11175173, 11105141) A beam position monitor(BPM) system is being installed to improve the beam position measurement of the injector at the upgrade project of Hefei Light Source (HLS II). The new BPM system is consists of 19 stripline BPMs and 19 Libera Brilliance Single Pass modules. Before installation, the response of the BPMs must be mapped to improve the accuracy of measurement. The theoretical equations of both position and quadrupole component of the BPM are calculated first, using both formula and matlab simulation. A laboratory calibration system is built. The inconsistency of Libera Brilliance Single Pass channels is measured to improve the accuracy of calibration. The calibrating results show the position sensitivity is less than 5% difference compare to the theoretical value, while the quadrupole component sensitivity is less than 10% difference.

MOPME053	Point Spread Function Study of X-ray Pinhole Camera in SSRF	radiation, synchrotron, synchrotron-radiation, storage-ring	592
	Z.C. Chen, J. Chen, G.Q. Huang, Y.B. Leng SSRF, Shanghai, People's Republic of China
	Funding: Supported by National Natural Science Foundation of China (11075198) An X-ray Pinhole Camera that has been used to present the transverse beam size with an intuitive grasp of the distribution of the beam radiation was installed on one beam-line of the storage ring in Shanghai Synchrotron Radiation Facility (SSRF). The real beam size however is a function of the image size of the CCD camera and the point spread function (PSF) of the system. The PSF was calculated but poorly tested. This article will present the measurement of the PSF with a series of beam based experiments and the consistency with the theoretical beam size.

MOPME069	Multi-OTR System for Linear Colliders	target, diagnostics, optics, linac	637
	J. Resta-López, A. Faus-Golfe IFIC, Valencia, Spain J. Alabau-Gonzalvo, R. Apsimon, A. Latina CERN, Geneva, Switzerland
	We study the feasibility of using a multi-Optical Transition Radiation (mOTR) system for fast transverse emittance reconstruction and x-y coupling correction in the Ring to Main Linac (RTML) of the future linear colliders: ILC and CLIC. OTR monitors are mature and reliable diagnostic tools that could be very suitable for the setup and tuning of the machine in single-bunch mode. Here we study the requirements for a mOTR system adapted to the optical conditions and beam parameters of the RTML of both the ILC and CLIC.

MOPME070	Emittance and Beta Functions Measurements for the MAX IV Linac	quadrupole, simulation, linac, controls	640
	N. Čutić, E. Mansten MAX-lab, Lund, Sweden
	We plan to determine beam emittance and Twiss parameters for the MAX IV linac using multiple-quadrupoles scans. We investigate the possibility to perform such scans using matching sections' quadrupoles combined with beam profile measurements by fluorescent YAG screens. Beam pipe size, resolution and screen saturation limits and strengths of quadrupoles are taken into consideration. Our approach to this problem using Kalman filter is presented.

MOPME075	Laser Based Stripping System for Measurement of the Transverse Emittance of H⁻ Beams at the CERN LINAC4	laser, electron, linac, background	652
	T. Hofmann, E. Bravin, U. Raich, F. Roncarolo CERN, Geneva, Switzerland B. Cheymol ESS, Lund, Sweden
	Funding: LA3NET is funded by the European Commission under Grant Agreement Number GA-ITN-2011-289191 The new LINAC4 at CERN will accelerate H⁻ particles to 160 MeV and allow high brightness proton beam transfers to the Proton Synchrotron Booster, via a charge-exchange injection scheme. This paper describes the conceptual design of a laser system proposed for transverse profile and emittance measurements based on photon detachment of electrons from the H⁻ ions. The binding energy of the outer electron is only 0.75 eV and can easily be stripped with a laser beam. Measuring the electron signal as function of the laser position allows the transverse beam profile to be reconstructed. A downstream dipole can also be used to separate the laser neutralized H⁰ atoms from the main H⁻ beam. By imaging these H⁰ atoms as a function of laser position the transverse emittance can be reconstructed in the same way as in traditional slit-and-grid systems. By properly dimensioning the laser power and spot size, this method results in negligible beam losses and is therefore non-destructive. In addition, the absence of material intercepting the H⁻ beam allows the measurement of a full power H⁻ beam. This paper will focus on the general design and integration of both the laser and H⁰ detector systems.

MOPWA033	Modelling of Parasitic Inductances of a High Precision Inductive Adder for CLIC	impedance, kicker, damping, coupling	738
	J. Holma, M.J. Barnes CERN, Geneva, Switzerland S.J. Ovaska Aalto University, School of Science and Technology, Aalto, Finland
	The CLIC study is exploring the scheme for an electron-positron collider with high luminosity and a nominal centre-of-mass energy of 3 TeV. The CLIC pre-damping rings and damping rings will produce, through synchrotron radiation, ultra-low emittance beam with high bunch charge. To avoid beam emittance increase, the damping ring kicker systems must provide extremely flat, high-voltage, pulses. The specifications for the extraction kickers of the DRs are particularly demanding: the flat-top of the pulses must be ±12.5 kV with a combined ripple and droop of not more than ±0.02 % (±2.5 V). An inductive adder is a very promising approach to meeting the specifications. However, the output impedance of the inductive adder needs to be well matched to the system impedance. The primary leakage inductance, which cannot be computed accurately analytically, has a significant effect upon the output impedance of the inductive adder. This paper presents predictions, obtained by modelling the 3D geometry of the adder structure and printed circuit boards using the FastHenry code, for primary leakage inductance.

MOPWA034	Electron Tracking Simulations in the Presence of the Beam and External Fields	electron, simulation, proton, space-charge	741
	M. Patecki, B. Dehning, G. Iadarola, M. Sapinski CERN, Geneva, Switzerland
	The ionisation profile monitors installed in the CERN LHC and SPS, makes use of the ionisation of small quantities of injected neon gas by the circulating beam. The electrons produced are guided towards the readout system using a combination of electric and magnetic fields. However, in the presence of the beam field their tracks are modified and the resulting profile is distorted. The Geant4 physics simulation package has been used to simulate the ionisation process, while the CERN-developed PyECLOUD code has been used for tracking the resulting ionised particles. In this paper the results of simulations are compared with observations, with conclusions presented on the accuracy of the reconstruction of high-intensity beam profiles.

MOPWA041	The New SLS Beam Size Monitor, First Results	laser, polarization, synchrotron, radiation	759
	Á. Saá Hernández, N. Milas, M. Rohrer, V. Schlott, A. Streun PSI, Villigen PSI, Switzerland Å. Andersson, J. Breunlin MAX-lab, Lund, Sweden
	Funding: This research has received funding from the European Commission under the FP7-INFRASTRUCTURES-2010-1/INFRA-2010-2.2.11 project TIARA (CNI-PP). Grant agreement no. 261905. An extremely small vertical beam size of 3.6 μm, corresponding to a vertical emittance of 0.9 pm, only about five times bigger than the quantum limit, has been achieved at the storage ring of the Swiss Light Source (SLS). The measurement was performed by means of a beam size monitor based on the imaging of the vertically polarized synchrotron radiation in the visible and UV spectral ranges. However, the resolution limit of the monitor was reached during the last measurement campaign and prevented further emittance minimization. In the context of the work package “SLS Vertical Emittance Tuning” of the TIARA collaboration, a new improved monitor was built. It provides larger magnification, an increase of resolution and enables two complementary methods of measurement: imaging and interferometry. In this paper we present the design, installation, commissioning, performance studies and first results obtained with the new monitor.

MOPWA049	Status Report of the FETS Photo Detachment Emittance Instrument at RAL	laser, ion, diagnostics, dipole	783
	C. Gabor STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom G.E. Boorman, A. Bosco, S.M. Gibson Royal Holloway, University of London, Surrey, United Kingdom G.E. Boorman, A. Bosco, S.M. Gibson JAI, Egham, Surrey, United Kingdom A.P. Letchford STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom P. Savage Imperial College of Science and Technology, Department of Physics, London, United Kingdom V.E. Scarpine Fermilab, Batavia, USA
	The Front End Test Stand at the Rutherford Appleton Laboratory (RAL) is being developed to demonstrate a chopped H⁻ beam of 60 mA at 3 MeV with 10% duty cycle. Due to the high beam power it is advisable to use the technique of photo detachment to avoid intrusive methods. It is intended to apply this technique to perform emittance measurements at the output of the RFQ at full power. This requires a dedicated diagnostics dipole with a special-made vacuum chamber giving room for the different beam paths necessary to install a particle detector to measure the produced neutrals. Other aspects are the beam transport and influence of the dipole and its fringe field to the beam transport Other considerations are the installation of the laser, the optics and the particle detector itself.

MOPWA059	Beam Emittance Measurements and Beam Transport Optimization at the Clatterbridge Cancer Centre	quadrupole, proton, cyclotron, scattering	810
	T. Cybulski, O. Karamyshev, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom A. Degiovanni TERA, Novara, Italy A. Kacperek, B. Marsland, I. Taylor, A. Wray The Douglas Cyclotron, The Clatterbridge Cancer Centre NHS Foundation Trust, Wirral, United Kingdom O. Karamyshev, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom
	Funding: Cockcroft Institute, Daresbury, Warrington, WA4 4AD, United Kingdom University of Liverpool, Liverpool, United Kingdom The QUASAR Group is preparing tests of the high energy physics LHCb VELO detector as a non–invasive online dose monitor at the 60 MeV proton therapy beam at the Clatterbridge Cancer Centre (CCC), UK. The proposed method relies on the cross-correlation between the beam halo signal as measured by VELO and the dose delivered to the patient, linked via the absolute intensity of the beam. In order to estimate the expected halo signal and the total beam intensity, studies into proton beam transport through the whole CCC beam line have been carried out. This required the measurement of beam emittance at several positions of the beam delivery system. Quadrupole scans have been realized using a CsI (Tl) scintillating screen in combination with an 8 bit, 13 Mpixel CCD camera. In this contribution, results from measurements are presented and include a discussion of the effects from dispersion in the beam. Experimental data are compared against earlier measurements performed in 1998 and are used as a basis for suggestions targeting an overall optimization of beam transport at CCC. * Assessing the Suitability of a Medical Cyclotron as an Injector for an Energy Upgrade, J. A. Clarke et all , CLRC Daresbury Laboratory, Warrington, UK

MOPWA061	A New Tool for Longitudinal Tomography in Fermilab's Main Injector and Recycler Rings	booster, controls, injection, space-charge	816
	N.J. Evans, S.E. Kopp The University of Texas at Austin, Austin, Texas, USA P. Adamson, D.J. Scott Fermilab, Batavia, USA
	Funding: U.S Department of Energy We are developing software to compute tomographic reconstructions of longitudinal phase space distributions in the Fermi National Accelerator Laboratory Main Injector and Recycler rings using data from existing resistive wall current monitors to diagnose beam quality at injection and provide input distributions for simulation of losses. Building on the algorithm developed by S. Hancock et al. at CERN the software is able to process a full synchrotron period of a Booster batch of 81 bunches with 18.94 ns spacing and a sampling rate of 2.5 GHz, in < 30 sec, or every ~270 injections. Processing an entire injection opens up the possibility of investigating coupled bunch instabilities via tomography. To speed reconstruction for use on a full injection, phase space maps are created once for a given set of parameters and saved for injections with similar machine settings. We present an overview of the system and studies done on the effect of small errors present including: random noise, mismatch between sampling rate and machine period, errors in locating bunch centers, and trigger jitter. Tomographic Measurements of Longitudinal Phase Space Density; 1998 ed. - Hancock, S et al - CERN-PS-98-030-RF

MOPWA073	A Turn-by-turn Beam Profile Monitor using Visible Synchrotron Radiation at CESR-TA	electron, synchrotron, synchrotron-radiation, radiation	849
	S. Wang, D. L. Rubin, C.R. Strohman CLASSE, Ithaca, New York, USA R.F. Campbell, R. Holtzapple CalPoly, San Luis Obispo, California, USA
	Funding: Work supported by the National Science Foundation and Department of Energy under contract numbers PHY-0734867, PHY-1002467, DMR-0936384, and DE-FC02-08ER41538, DE-SC0006505 A fast beam profile monitor using visible synchrotron radiation (SR) has been constructed and installed in Cornell Electron Storage Ring. This monitor utilizes fast readout electronics based on the Hamamatsu H7260K multi-anode photomultiplier, which has a 32-channel linear array with 1mm channel pitch and sub-nanosecond rise time. In a low emittance lattice at 2 GeV, a double-slit interferometer is employed to measure the horizontal beam size. After careful calibration of the interference pattern, the horizontal beam size within a range of 100 to 500 microns can be measured with a precision of ±5 microns. Due to finite array size, the small vertical beam size is measured by imaging the pi-polarized component of the SR. The fast beam profile monitor is capable of measuring bunch-by-bunch turn-by-turn transverse beam sizes, which eliminates beam jitter inherent when imaging the average beam size with a CCD camera. Details of hardware and software controls are also discussed.

MOPWA076	Improvements to Existing Jefferson Lab Wire Scanners	optics, diagnostics, controls, linac	855
	M.D. McCaughan, M.G. Tiefenback, D.L. Turner JLAB, Newport News, Virginia, USA
	This poster will detail the augmentation of selected existing CEBAF wire scanners with commercially available hardware, PMTs, and self created software in order to improve the scanners both in function and utility. Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The U.S. Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for U.S. Government purposes.

MOPWO009	Numerical Studies on the Impact of Ionized Residual Gas on an Electron Beam in an ERL	ion, electron, simulation, linac	903
	G. Pöplau, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany A. Meseck HZB, Berlin, Germany
	Funding: Supported by BMBF under contract number 05K10HRC Energy Recovery Linacs (ERLs) are the most promising candidates for next-generation light sources now under active development. An optimal performance of these machines requires the preservation of the high beam brightness generated in the injector. For this, the impact of the ionized residual gas on the beam has to be avoided as it causes instabilities and emittance growth. Typical measures to reduce the effect of ion clouds are clearing electrodes and clearing gaps in the bunch train. In this paper, we present numerical studies of the impact of ion clouds on the electron bunch train. The simulations are performed with the software package MOEVE PIC Tracking developed at Rostock University. ’The model for the bunch and the ion cloud takes into account a distribution of macro particles. The interaction of the bunch with the ion cloud is computed with a 3D space charge model. Hence, particle tracking allows for detailed studies of bunch characteristics such as the emittance. The presented numerical investigations take into account the parameters of the ERL BERLinPro with the objective to deduce appropriate measures for the design and operation of BERLinPro.

MOPWO023	Upgrade and Systematic Measurement Campaign of the ATF2 Multi-OTR System	target, coupling, wakefield, extraction	933
	A. Faus-Golfe, J. Alabau-Gonzalvo, C. Blanch Gutierrez, J. Resta-López IFIC, Valencia, Spain J. Cruz, E. Marín, D.J. McCormick, G.R. White, M. Woodley SLAC, Menlo Park, California, USA
	A multi-Optical Transition Radiation (mOTR) system made of four stations is being used routinely since September 2011 for transverse beam size measurement and emittance reconstruction in the extraction line of ATF2, providing diagnostic support during the ATF2 tuning operation. Furthermore it is also an excellent tool for fast transverse coupling correction. Due to the compactness of the current design the system has an influence in the increase of the transverse emittance due to wakefield effects when a simultaneous measurement is made. To avoid this effect a new target holder and a new optics has been designed and implemented. In this paper we describe the present status of the ATF2 mOTR system, showing recent performance results, and hardware design improvements.

MOPWO024	Design of the CLIC Pre-Main Linac Collimation System	collimation, linac, wakefield, damping	936
	R. Apsimon, A. Latina, D. Schulte, J.A. Uythoven CERN, Geneva, Switzerland J. Resta-López IFIC, Valencia, Spain
	A main beam collimation system, upstream of the main linac, is essential to protect the linac from particles in the beam halo. The proposed system consists of an energy collimation (EC) system just after the booster linac near the start of the Ring-to-Main Linac (RTML) transfer line and an EC and betatron collimation (BC) system at the end of the RTML, just before the main linac. The design requirements are presented and the cleaning efficiency of the proposed systems is analysed for different design choices.

MOPWO032	SPS Scraping and LHC Transverse Tails	injection, beam-losses, luminosity, controls	957
	L.N. Drøsdal, K. Cornelis, B. Goddard, V. Kain, M. Meddahi, O. Mete, B. Salvachua, G. Valentino, E. Veyrunes CERN, Geneva, Switzerland
	All high-intensity LHC beams have to be scraped before extraction from the SPS to remove the non-Gaussian transverse tails of the particle distributions. The tail particles would otherwise cause unacceptably high losses during injection or other phases of the LHC cycle. Studies have been carried out to quantify the scraping using injection losses and emittance measurements from wire scanners as diagnostics. Beams scraped in the SPS were scraped again in the LHC with collimators to investigate possible tail repopulation. The results of these studies will be presented in this paper.

MOPWO039	Experience with High-intensity Beam Scraping and Tail Populations at the Large Hadon Collider	beam-losses, injection, hadron, diagnostics	978
	S. Redaelli, R. Bruce, F. Burkart, D. Mirarchi, B. Salvachua, G. Valentino, D. Wollmann CERN, Geneva, Switzerland R.W. Aßmann DESY, Hamburg, Germany G. Valentino University of Malta, Information and Communication Technology, Msida, Malta
	The population of beam tails at the LHC is source of concern because even small fractions of the total beam intensity could represent a potential danger is case of slow or fast losses, e.g. caused by orbit transients or by collimator movements. Different studies have been performed using the technique of collimator scans to probe the beam tail population, for different beam energies and beam intensities. The experience accumulated during the operation at 3.5 TeV and 4 TeV is reviewed and extrapolations to higher energies are considered.

MOPWO046	Simulations and Measurements of Beam Losses on LHC Collimators during Beam Abort Failures	simulation, proton, collimation, kicker	996
	L. Lari, C. Bracco, R. Bruce, B. Goddard, S. Redaelli, B. Salvachua, G. Valentino CERN, Geneva, Switzerland A. Faus-Golfe, L. Lari IFIC, Valencia, Spain G. Valentino University of Malta, Information and Communication Technology, Msida, Malta
	Funding: The HiLumi LHC Design Study is included in the HL-LHC project and is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404. One of the main purposes of tracking simulations for collimation studies is to produce loss maps along the LHC ring, in order to identify the level of local beam losses during nominal and abnormal operation scenarios. The SixTrack program is the standard tracking tool used at CERN to perform these studies. Recently, it was expanded in order to evaluate the proton load on different collimators in case of fast beam failures. Simulations are compared with beam measurements at 4 TeV. Combined failures are assumed which provide worst-case scenarios of the load on tungsten tertiary collimators.

MOPWO057	A Precise Beam Dynamics Model of the PSI Injector 2	space-charge, cyclotron, simulation, injection	1020
	A.M. Kolano, R.J. Barlow University of Huddersfield, Huddersfield, United Kingdom A. Adelmann, C. Baumgarten PSI, Villigen PSI, Switzerland
	The Injector 2 at PSI (Paul Scherrer Institut), is a 72 MeV separate sector cyclotron producing a high intensity proton beam up to 3 mA CW, which is subsequently injected to the 590 MeV Ring Cyclotron. The injection energy of the pre-bunched beam is 870 keV at an intensity of 10 to 11 mA. In this paper we describe a full 3D model of the PSI injector 2, starting just before the two bunchers and including the multi stage collimation scheme in the cyclotron. The precise beam dynamics model is based on the OPAL (Object Oriented Parallel Accelerator Library) simulation code. OPAL is a tool for charged-particle optic calculations in large accelerator structures and beam lines including 3D space charge. The presented model will be validated with data from radial profile measurements and loss rates from the collimators and the electrostatic septum in the Injector 2. Based on this model we will estimate the intensity limit of this machine and comment of future operation modes.

MOPWO061	Numerical Approaches for Simulation of Stochastic Cooling in 2D Phase Space	simulation, coupling, electromagnetic-fields, storage-ring	1028
	M. Dolinska NASU/INR, Kiev, Ukraine C. Dimopoulou, A. Dolinskyy, F. Nolden GSI, Darmstadt, Germany
	A consolidated fluid-dynamics algorithm for the analysis of beam dynamics under the influence of the electromagnetic field is presented. Aiming at simulating stochastic cooling of particle beams in 2D space, two numerical algorithms solving the 2D Fokker-Planck Equation are described. As an alternative approach, a numerical method based on the macro-particle tracking turn in turn in the ring (i.e. in the time domain) is introduced. Some results of the simulation of the stochastic cooling in the Collector Ring by both methods are discussed.

MOPWO062	A Parallel Multi-objective Differential Evolution Algorithm for Photoinjector Beam Dynamics Optimization	controls, electron, solenoid, gun	1031
	J. Qiang, C.E. Mitchell, S. Paret, R.D. Ryne LBNL, Berkeley, California, USA Y.X. Chao UCB, Berkeley, California, USA
	Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231 In photoinjector design, there is growing interest in using multi-objective beam dynamics optimization to minimize the final transverse emittances and to maximize the final peak current of the beam. Most previous studies in this area were based on genetic algorithms. Recent progress in optimization suggests that the differential evolution algorithm could perform better in comparison to the genetic algorithm. In this paper, we propose a new parallel multi-objective optimizer based on the differential evolution algorithm for photoinjector beam dynamics optimization. We will discuss the numerical algorithm and some benchmark examples. This algorithm has the potential to significantly reduce the computation time required to reach the optimal Pareto solution.

MOPWO073	Design and Simulation of an Extraction Section for the University of Maryland Electron Ring	extraction, dipole, simulation, quadrupole	1052
	K.J. Ruisard, B.L. Beaudoin, S. Bernal, J.A. Butcher, I. Haber, R.A. Kishek, T.W. Koeth, D.F. Sutter UMD, College Park, Maryland, USA
	Funding: Supported by the US Dept. of Energy, Office of High Energy Physics, and by the US Dept. of Defense, Office of Naval Research and the Joint Technology Office. The University of Maryland Electron Ring (UMER) is a low-energy scaled facility for the study of intense beam dynamics, relevant to higher energy, high intensity accelerators. Many parameters crucial to understanding space charge dominated beam evolution, such as transverse emittance and longitudinal temperature, require the use of turn-by-turn interceptive diagnostics. To meet this need, we plan to implement an extraction section with a fast-pulsed electric-field kicker. This paper presents a suite of simulations used to guide the design process and predict extraction performance, using the WARP Particle-in-cell (PIC) code. Simulations in a transverse slice geometry predict beam trajectory and monitor beam evolution through extraction. After isolating a design based on centroid tracking, extraction acceptance is probed and an analysis proposed to estimate the error tolerances of the new ring elements.

MOPWO085	A Hybrid Technique for Computing Courant-Snyder Parameters from Beam Profile Data	space-charge, simulation, linac, DTL	1073
	C.K. Allen ORNL, Oak Ridge, Tennessee, USA E.N. Dai Washington University in St. Louis, St. Louis, USA
	Funding: Work supported by ORNL/SNS, which is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725. We present a technique for computing the Courant-Snyder parameters of a charged-particle beam from profile measurement data. Such algorithms are not new, but this particular method has very robust convergence properties resulting from a novel approach that combines both deterministic and non-deterministic methods. The general idea is as follows: given a model of the beamline, in the zero-current case it is possible to compute the Courant-Snyder parameters directly from profile data using a deterministic, linear-algebraic approach. For the finite beam current case we can construct a smooth curve of these deterministic solutions starting from the zero-current solution and terminating at the finite-current case. We are guaranteed convergence, and convergence to the finite-current solution connected to the zero-current Courant-Snyder parameters. This approach avoids the convergence issues associated with a fully iterative, non-deterministic method. The details of the technique are outlined and examples are presented using profile data taken from the SNS accelerator.

TUYB101	Progress in Super B-Factories	luminosity, linac, positron, alignment	1096
	K. Akai KEK, Ibaraki, Japan
	The upgrade of B-Factories to Super B-Factories, which will search for new physics beyond the Standard Model, opens the way for new luminosity frontier. The status of Super B-Factories will be reported.
	Slides TUYB101 [42.300 MB]

TUOCB103	Quasi Traveling Wave Side Couple RF Gun for SuperKEKB	gun, cavity, focusing, cathode	1117
	T. Natsui, Y. Ogawa, M. Yoshida, X. Zhou KEK, Ibaraki, Japan
	We are developing a new RF gun for SuperKEKB. High charge low emittance electron and positron beams are required for SuperKEKB. We will generate 7.0 GeV electron beam at 5 nC 20 mm-mrad by J-linac. In this linac, a photo cathode S-band RF gun will be used as the electron beam source. For this reason, we are developing an advanced RF gun. We have tested a Disk and Washer (DAW) type RF gun. Additionally, another new RF gun which has two side coupled standing wave field is developed. We call it quasi traveling wave side couple RF gun. This gun has a strong focusing field at the cathode and the acceleration field distribution also has a focusing effect. The design of RF gun and experimental results will be shown.
	Slides TUOCB103 [2.959 MB]

TUODB102	Intrabeam Scattering Studies for Low Emittance of BAPS	wiggler, damping, storage-ring, lattice	1123
	S.K. Tian, Y. Jiao, J.Q. Wang, G. Xu IHEP, Beijing, People's Republic of China
	In modern storage ring light sources, intra-beam scattering (IBS) is often thought of as a fundamental limitation to achieving ultra-low emittance and hence higher brightness. Beijing Advanced Photon Source (BAPS) is under design at Institute of High Energy Physics (IHEP) which aims to emittance less than 1nm at 5GeV. To improve the coherence and high brightness, low emittance- in both transverse planes at the diffraction limit for the range of x-ray wavelengths(≈10 pm)- is being pursued. Thus, due to the very low emittance, intra-beam scattering effect is an issue. Accurate estimation to check if the design goal can be reached is necessary. In this paper, we use the 6-D accelerator simulation code-elegant and Accelerator Toolbox (AT)-a collection of tools to model storage rings in the MATLAB environment. Based on a temporary design lattice of BAPS, we present the results of particle simulation study of intra-beam scattering effect versus the beam energy, the emittance coupling factor, the bunch length, the bunch current and so on. We also studied the mitigating method by adopting damping wigglers in one or more dispersion-free regions.
	Slides TUODB102 [2.338 MB]

TUODB103	Recent Results from CesrTA Intrabeam Scattering Investigations	coupling, simulation, damping, scattering	1126
	M. P. Ehrlichman, A. Chatterjee, W. Hartung, D.P. Peterson, N.T. Rider, D. L. Rubin, D. Sagan, J.P. Shanks, S. Wang CLASSE, Ithaca, New York, USA
	Funding: This research was supported by NSF and DOE contracts PHY-0734867, PHY-1002467, PHYS-1068662, DE-FC02-08ER41538, DE-SC0006505. Manifestation of intrabeam scattering (IBS) in an electron/positron storage ring depends on the radiation damping time in two ways. First, the beam size is the equilibrium of the IBS growth rate in each of the three degrees of freedom and corresponding damping rates. Second, scattering events that occur less frequently than order once per damping time contribute to non-Gaussian tails that are invisible to our beam size monitors. The tail cut procedure excludes these relatively rare events in the calculation of equilibrium beam size. In machines with short damping times, the tail cut significantly reduces the effective IBS growth rate. At CesrTA, we measure the dependence of beam size on bunch charge in IBS-dominated beams. We vary the vertical emittance using a closed optics bump that increases the vertical dispersion and transverse coupling in the wiggler regions. Measurements are taken at both 2.1 and 2.3 GeV. Here we report the results of these experiments and compare those results to theory.
	Slides TUODB103 [1.221 MB]

TUOAB201	Ultra-Short X-ray Pulse Generation by Electron Beam Slicing in Storage Rings	electron, storage-ring, linac, photon	1134
	L.-H. Yu, F.J. Willeke BNL, Upton, Long Island, New York, USA
	Funding: Department of Energy, USA We propose a new method to generate ultra-short x-ray pulses using focused short low energy (5-10MeV) electron bunch to slice a short electron bunch from the electron bunches in a synchrotron radiation storage ring. When the low energy electron bunch crosses from top the high energy electron bunch at right angle, its coulomb force will kick a short slice of high energy electrons away from the core of the storage ring electron bunch. When the low energy electron bunch (about 50 pC) is focused to about 50 micron size and compressed to about 150fs bunch length and is positioned on top of the high energy electron bunch by a distance about 30 micron, the coulomb force is sufficient to give a kick vertically to the electrons within a short slice of the storage ring bunch about 200 fs long with a deflection about 4 micro-radian. This is sufficient to deflect the slice away from the core by a separation of 5 times the angular divergence of the beam. The separated slice when passing through an undulator, will radiate ulstra-short x-ray pulses at about 200 fs. We discuss the advantages and challenges of this new method. We provide data to demonstrate the feasibility of this method.
	Slides TUOAB201 [1.578 MB]

TUOAB203	ESRF Upgrade Phase II	lattice, storage-ring, vacuum, brilliance	1140
	J.-L. Revol, P. Berkvens, J.C. Biasci, J-F. B. Bouteille, N. Carmignani, F. Ewald, L. Farvacque, A. Franchi, L. Goirand, M. Hahn, L. Hardy, J. Jacob, J.M. Koch, G. Lebec, S.M. Liuzzo, B. Nash, T.P. Perron, E. Plouviez, P. Raimondi, K.B. Scheidt, V. Serrière ESRF, Grenoble, France
	Four years after the launch of the Upgrade Programme, the ESRF is midway through its first phase (2009-2015) and has defined the objectives for the ensuing second phase. The first phase paved the way to a new generation of nano-beam X-ray beamlines fed by an X-ray source itself substantially improved in terms of reliability, stability and brilliance. The second phase envisions a major upgrade of the source to best serve the science case of this new generation of beamlines. In December 2012, the ESRF Council endorsed Management's proposal to launch the technical design study of a new 7-bend achromat lattice. This new configuration will allow the ESRF storage ring to operate with a decrease in horizontal emittance by a factor of about 30 and a consequent increase in brilliance and coherence of the photon beam. The increase will be substantially higher at X-ray energies larger than 50 keV.
	Slides TUOAB203 [3.664 MB]

TUPEA007	Spontaneous Radiation Calculations for the European XFEL	undulator, radiation, electron, FEL	1176
	I.V. Agapov, G. Geloni XFEL. EU, Hamburg, Germany O.V. Chubar BNL, Upton, Long Island, New York, USA M. Scheer, M. Titze HZB, Berlin, Germany N.V. Smolyakov, S.I. Tomin NRC, Moscow, Russia
	Calculating spontaneous radiation emission from long undulators such as those present in the European XFEL, being background to FEL radiation, is still important for several diagnostics and science cases. For realistic setups, and including effects of electron beam focusing, emittance and energy spread in the electron beam, these calculations should be performed numerically. We present these calculations for several electron beam and undulator parameters performed by various codes. Sensitivity of different spontaneous radiation characteristics, in various collection schemes, to the electron beam and undulator magnetic field parameters is studied

TUPEA017	Monoenergetic Electron Beams with Ultralow Normalized Emittance Generated from Laser-Gas Interaction	laser, electron, plasma, simulation	1196
	D.Z. Li, J. Gao, K. Huang, J. Jiarui, Y. Ma IHEP, Beijing, People's Republic of China L.M. Chen, W.C. Yan Institute of Physics, Chinese Academy of Sciences, Beijing, People's Republic of China
	High quality electron bunches are generated by using 2 TW, 80 fs, high contrast laser pulses interacting with helium gas targets. In optimized condition, we get tens MeV monoenergetic electron beams with small energy spread and the normalized emittance 0.07π mm·mrad. Due to its ultra small emittance and high initial energy, such bunch is very suitable for high current linear accelerators.

TUPEA042	Linac Design for Dalian Coherent Light Source	linac, FEL, simulation, laser	1226
	M. Zhang, H.X. Deng, D. Gu, Q. Gu SINAP, Shanghai, People's Republic of China
	Dalian Coherent Light (DCL) Source is a FEL user facility in which HGHG scheme is adopted. Beam quality requirements for the linear accelerator (linac) are critical, including not only the beam brightness, but also the stability and the reliability. In this paper, optimization study is performed for the linac. Based on beam stability simulation in the longitudinal direction, the tolerant budget is formed for the short period jitter. For the transverse orbit error, beam based alignment (BBA) technique is implemented by beam dynamics simulations and the transverse jitter is also presented accordingly. Measurement method for the beam quality is also described in the paper.

TUPEA050	Extension of the MAX IV Linac for a Free Electron Laser in the X-ray Region	linac, FEL, undulator, electron	1244
	F. Curbis, N. Čutić, M. Eriksson, O. Karlberg, F. Lindau, A. Mak, E. Mansten, S. Thorin, S. Werin MAX-lab, Lund, Sweden
	The 3 GeV linac for the MAX IV laboratory is currently under construction in Lund (Sweden). As full energy injector for the MAX IV rings, a thermionic gun will be used to create electrons. However a photocathode gun planned for a short pulse facility (SPF) will deliver small emittance and ultra-short electron bunches that will be suitable to also drive a Free-Electron Laser. Moreover extending the linac energy with 1 or 2 GeV will give the opportunity to get closer to 1 Angstrom radiation with much more flexibility and better performances. Given these opportunities at the MAX IV laboratory, a free electron laser is envisaged in the long term perspective of the facility. In this study we investigate the case of a 5 GeV machine which can produce radiation in the X-ray region. The FEL design will benefit from the implementation of self-seeding, to enhance stability of the central wavelength and spectral bandwidth. Tapering along variable gap undulators will help to extract the maximum photon flux and increase the brilliance of the source. Among others, this kind of machine would be suitable for time resolved experiments and imaging.

TUPEA052	Design Study for a CERN Short Base-Line Neutrino Facility	target, proton, extraction, secondary-beams	1250
	R. Steerenberg, M. Calviani, I. Efthymiopoulos, A. Ferrari, B. Goddard, R. Losito, M. Nessi, J.A. Osborne, L. Scibile, H. Vincke CERN, Geneva, Switzerland P.R. Sala Istituto Nazionale di Fisica Nucleare, Milano, Italy
	A design study has been initiated at CERN for the conception and construction of a short base line neutrino facility, using a proton beam from the CERN Super Proton Synchrotron (SPS) that will be transferred to a new secondary beam production facility, which will provide a neutrino beam for experiments and detector R&D. This paper resumes the general layout of the facility together with the main primary and secondary beam parameters and the choices favoured for the neutrino beam production.

TUPEA059	CLARA Accelerator Design and Simulations	linac, diagnostics, FEL, laser	1268
	P.H. Williams, D. Angal-Kalinin, J.K. Jones, B.P.M. Liggins, J.W. McKenzie, B.L. Militsyn STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom D. Angal-Kalinin, J.K. Jones, B.P.M. Liggins, J.W. McKenzie, P.H. Williams Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Funding: Science & Technology Facilities Council We present the accelerator design for CLARA (Compact Linear Advanced Research Accelerator) at Daresbury Laboratory. CLARA will be a testbed for novel FEL configurations. The accelerator will consist of an RF photoinjector, S-band acceleration and transport to 250 MeV including X-band linearisation and magnetic bunch compression. We describe the transport in detail including dedicated diagnostic sections. Beam dynamics simulations are then used to define a set of operating working points suitable for the different FEL schemes intended to be tested on CLARA.

TUPEA071	THz Bench Tests of a Slab-symmetric Dielectric Waveguide	acceleration, laser, simulation, wakefield	1292
	F. Lemery, H. Panuganti, P. Piot Northern Illinois University, DeKalb, Illinois, USA D. Mihalcea, P. Piot Fermilab, Batavia, USA P. Stoltz Tech-X, Boulder, Colorado, USA
	Funding: This work is supported by DTRA contract HDTRA1-10-1-0051 and by the U.S. DOE contracts DE-FG02-08ER41532 and DE-AC02-07CH11359. Dielectric-lined waveguides (DLW) are becoming more popular for beam driven acceleration applications. An experiment to demonstrate beam-driven acceleration using a slab-symmetric dielectric-lined waveguide driven by a flat beam is in preparation at the Advanced Superconducting Test Accelerator (ASTA) at Fermilab. In this paper we characterize the structure using a THz pulse obtained from optical rectification using an amplified laser pulse. After propagation through the DLW structure, the THz pulse is analyzed using a Michelson interferometer and single-shot electro-optical imaging. Data for various gap size will be presented.

TUPEA072	Toward a Dielectric-Wakefield Energy Doubler at the Fermilab's Advanced Superconducting Test Accelerator	acceleration, electron, simulation, wakefield	1295
	F. Lemery, D. Mihalcea, P. Piot, C.R. Prokop Northern Illinois University, DeKalb, Illinois, USA P. Piot, Y.-E. Sun Fermilab, Batavia, USA P. Stoltz Tech-X, Boulder, Colorado, USA
	Funding: This work is supported by DTRA contract HDTRA1-10-1-0051 and by the U.S. DOE contracts DE-FG02-08ER41532 and DE-AC02-07CH11359. The Advanced Superconducting Test Accelerator (ASTA), presently under construction at Fermilab, will produce high-charge (~<3 nC) electron bunches with energies ranging from 50 to eventually 750 MeV. The facility is based on a superconducting linac capable of producing up to 3000 bunches in 1-ms macropulses repeated at 5 Hz. In this paper we explore the use of a short dielectric-lined-waveguide (DLW) linac to significantly increase the bunch energy. The method consists in (1) using advanced phase space manipulation techniques to shape the beam distribution and enhance the transformer ratio, and (2) optimize the generation and acceleration of a low-charge witness bunches. Start-to-end simulations of the proposed concept are presented. This DLW module could also be used to test some aspects of a recently proposed concept for a multiuser short-wavelength free-electron laser utilizing a series of DLW linacs. C. Jing et al., “A Compact Soft X-ray Free-Electron Laser Facility based on a Dielectric Wakefield Accelerator”, Advanced Photon Source LS Note LS-332, Argonne National Laboratory (2012).

TUPEA086	Femtosecond Electron Beam and X-ray Beams at the Linac Coherent Light Source	FEL, linac, electron, laser	1316
	Y.T. Ding, A. Brachmann, F.-J. Decker, R.C. Field, J.C. Frisch, Z. Huang, R.H. Iverson, H. Loos, H.-D. Nuhn, D.F. Ratner, J.L. Turner, J.J. Welch, J. Wu, F. Zhou SLAC, Menlo Park, California, USA P. Emma LBNL, Berkeley, California, USA
	Generation of ultrashort x-ray pulses (femtoseconds to attoseconds) is attracting much attention within the x-ray FEL user community. At the Linac Coherent Light Source (LCLS), we have successfully delivered femtosecond x-ray pulses to the users with two operating modes – low-charge (20-40pC) scheme and emittance spoiling foil method. Diagnostics on the femtosecond beams is also a challenging topic and good progresses have been made at LCLS. In this paper we report the experimental studies on the two femtosecond operation schemes, the x-ray performance and also the diagnostic progress.

TUPFI002	Electron Cloud and Scrubbing Studies for the LHC	injection, electron, dipole, luminosity	1331
	G. Iadarola Naples University Federico II, Science and Technology Pole, Napoli, Italy G. Arduini, V. Baglin, H. Bartosik, C.O. Domínguez, J. Esteban Müller, G. Iadarola, G. Rumolo, E.N. Shaposhnikova, L.J. Tavian, F. Zimmermann CERN, Geneva, Switzerland C.O. Domínguez EPFL, Lausanne, Switzerland G.H.I. Maury Cuna CINVESTAV, Mexico City, Mexico
	Electron cloud build-up resulting from beam-induced multipacting is one of the major limitations for the operation of the LHC with beams with close bunch spacing. Electron clouds induce unwanted pressure rise, heat loads on the beam screens of the superconducting magnets and beam instabilities. Operation with bunch spacing of 50 ns in 2011 and 2012 has required decreasing the Secondary Electron Yield of the beam screens below the multipacting threshold for beams with this bunch spacing. This was achieved by continuous electron bombardment induced by operating the machine with high intensity beams with 50 and 25 ns spacing during dedicated periods at injection energy (450 GeV) and at top energy (3.5 and 4 TeV). The evolution of the Secondary Electron Yield during these periods, at different sections of the machine, can be estimated by pressure, heat load and by bunch-by-bunch RF stable phase measurements. The experimental information on the scrubbing process will be discussed and a possible “scrubbing strategy” to allow the operation with 50ns and 25ns beams after the Long Shutdown in 2013-2014 will be presented.

TUPFI004	Longitudinal Manipulation to Obtain and Keep the Low Emittance and High Charge Electron Beam for SuperKEKB Injector	wakefield, laser, alignment, gun	1337
	M. Yoshida, N. Iida, T. Natsui, Y. Ogawa, S. Ohsawa, H. Sugimoto, L. Zang, X. Zhou KEK, Ibaraki, Japan
	The design strategy of SuperKEKB is based on the.nano-beam scheme. The dynamic aperture decreases due to the very small beta function at the interaction point. Thus the injector upgrade is required to obtain the low emittance and high charge beam corresponding to the short beam life and small injection acceptance. The required beam parameters are 5 nC, 20 mm mrad and 4 nC, 6 mm mrad for the electron and positron respectively. For the electron beam, we installed new photocathode RF-Gun with the focusing electric field and temporal adjusting laser system. Further the projected emittance dilution in the LINAC is an important issue for the low emittance injection. The longitudinal bunch length and shape is an important key to avoid the space charge effect and emittance dilution. The longitudinal manipulation using the temporal adjusting laser system and the bunch compression will be presented. Further the longitudinal bunch measurement will be also presented.

TUPFI020	Towards a Symmetric Momentum Distribution in the Muon Ionization Cooling Experiment	simulation, solenoid, quadrupole, collider	1376
	O.M. Hansen University of Oslo, Oslo, Norway A.P. Blondel DPNC, Genève, Switzerland I. Efthymiopoulos, O.M. Hansen CERN, Geneva, Switzerland
	The Muon Ionization Cooling Experiment (MICE) is under development at Rutherford Appleton Laboratory (UK). It's a proof-of-principle experiment for ionization cooling, which is a prerequisite for a future Neutrino Factory(NF) or a Muon Collider. The muon beam is designed to have a symmetrical momentum distribution in the cooling channel of the NF. In the MICE beamline pions are captured by a quadrupole triplet, then pion momentum is selected by dipole 1 (D1) after which the pions decay to muons in the decay solenoid. After the decay solenoid, the muon beam momentum is selected by dipole 2 (D2), the beam is focused in two quadrupole triplets and is finally characterized by a set of detectors. By doing a D1-scan of the currents, where the optics parameters are scaled according to the pion momentum, from 238-450 MeV/c the muon momentum distribution is changed. In this paper simulation results from G4Beamline and real data from MICE are presented and compared.

TUPFI024	Influence of the Ats Optics on Intra-Beam Scattering for HL-LHC	optics, luminosity, simulation, collider	1388
	M. Schaumann, R. Bruce, J.M. Jowett CERN, Geneva, Switzerland M. Schaumann RWTH, Aachen, Germany
	In the future High Luminosity (HL-)LHC the influence of intra-beam scattering (IBS) will be stronger than in the present LHC, because of higher bunch intensity, small emittance and new optics. The new ATS-optics scheme modifies the lattice in the arcs around the main interaction points (IP) to provide β* values as small as 0.15m in the IP, however those modifications affect the IBS growth rates. In this paper proton IBS emittance growth rates are calculated with MADX and the Collider Time Evolution (CTE) program for two ATS-optics versions, different settings of the crossing angles and required corrections and various beam conditions at injection (450 GeV) and collision (7 TeV) energy. CTE simulations of the expected luminosity, intensity, emittance and bunch length evolution during fills are also presented

TUPFI025	Bunch-by-Bunch Analysis of the LHC Heavy-Ion Luminosity	luminosity, injection, simulation, ion	1391
	M. Schaumann, J.M. Jowett CERN, Geneva, Switzerland
	After the first run in 2010, the LHC continued its heavy-ion operation with collisions of lead nuclei in late 2011. The beam dynamics of those high intensity lead beams are strongly influenced by intra-beam scattering (IBS), especially on the injection plateau. Each batch injected from the SPS spends a different time at injection, introducing significant changes from batch to batch. Within the batches there is an even larger spread imprinted by the SPS injection plateau. This results in a spread of the luminosity produced in each bunch crossing. The particle losses during collisions are dominated by nuclear electromagnetic processes, leading to a non-exponential intensity decay during the fill and short luminosity lifetime at 3.5 Z TeV. The luminosity, emittance, intensity and bunch length evolution of the 2011 run was analysed bunch-by-bunch and compared with simulations. Based on this analysis, estimates of the potential luminosity performance at 6.5 Z TeV, after the present shutdown, are given.

TUPFI026	Investigations of the LHC Emittance Blow-Up during the 2012 Proton Run	injection, luminosity, proton, target	1394
	M. Kuhn Uni HH, Hamburg, Germany G. Arduini, P. Baudrenghien, J. Emery, A. Guerrero, W. Höfle, V. Kain, M. Lamont, T. Mastoridis, F. Roncarolo, M. Sapinski, M. Schaumann, R.J. Steinhagen, G. Trad, D. Valuch CERN, Geneva, Switzerland
	About 30 % of the potential luminosity performance is lost through the different phases of the LHC cycle, mainly due to transverse emittance blow-up. Measuring the emittance growth is a difficult task with high intensity beams and changing energies. Improvements of the LHC transverse profile instrumentation helped to study various effects. A breakdown of the growth through the different phases of the LHC cycle is given as well as a comparison with the data from the LHC experiments for transverse beam size. In 2012 a number of possible sources and remedies have been studied. Among these are intra beam scattering, 50 Hz noise and the effect of the transverse damper gain. The results of the investigations are summarized in this paper. Requirements for transverse profile instrumentation for post LHC long shutdown operation to finally tackle the emittance growth are given as well.

TUPFI028	Beam Losses Through the LHC Operational Cycle in 2012	proton, beam-losses, luminosity, injection	1400
	G. Papotti, A.A. Gorzawski, M. Hostettler, R. Schmidt CERN, Geneva, Switzerland
	We review the losses through the nominal LHC cycle for physics operation in 2012. The loss patterns are studied and categorized according to timescale, distribution, time in the cycle, which bunches are affected, whether coherent or incoherent. Possible causes and correlations are identified, e.g. to machine parameters or instability signatures. A comparison with losses in the previous years of operation is also shown.

TUPFI029	Luminosity Lifetime at the LHC in 2012 Proton Physics Operation	luminosity, target, proton, optics	1403
	M. Hostettler, G. Papotti CERN, Geneva, Switzerland
	In 2012, the LHC was operated at 4 TeV flat top energy with beam parameters that allowed exceeding a peak instantaneous luminosity of 7500 (ub*s)^-1 and a total of 23 fb^-1 integrated luminosity in the ATLAS and CMS experiments. This paper elaborates on the evolution of the LHC luminosity and luminosity lifetime during proton physics fills and through the year 2012. Bunch to bunch differences and the impact of different machine settings are highlighted.

TUPFI037	Collimation Down to 2 Sigma in Special Physics Runs in the LHC	proton, scattering, background, luminosity	1427
	H. Burkhardt, S. Jakobsen, S. Redaelli, B. Salvachua, G. Valentino CERN, Geneva, Switzerland
	We report on observations with collimation very close to the beam. Primary collimators were moved in small steps down to 2 σ from the beam axis to allow for measurements of very forward proton scattering in special high-beta runs in the LHC. We studied the reduction in intensity as a function of collimator position which provides information about the halo shape. After scraping at 2 σ, collimators were retracted to 2.5 σ. This allowed for measurements of very forward proton-proton scattering with roman pot detectors at 3 σ from the beam axis at acceptable background levels for about an hour. Good background conditions were restored by another scraping with primary collimators at 2 σ. Beam lifetimes and halo repopulation times were found to be sufficiently long to allow for several hours of data taking between scraping in a single LHC fill.

TUPFI042	Beam Parameters and Luminosity Time Evolution for an 80-km VHE-LHC	luminosity, radiation, damping, collider	1442
	C.O. Domínguez, F. Zimmermann CERN, Geneva, Switzerland
	The Very High Energy LHC (VHE-LHC) is a recently proposed proton-proton collider in a new 80-km tunnel. With a dipole field of 15-20 T it would provide a collision energy of 76-100 TeV c.m. We discuss the VHE-LHC beam parameters and compute the time evolution of luminosity, beam current, emittances, bunch length, and beam-beam tune shift during a physics store. The results for VHE-LHC are compared with those for HE-LHC, a 33-TeV (20-T field) collider located in the existing LHC tunnel.

TUPFI046	The MICE Experiment	solenoid, target, simulation, quadrupole	1454
	A.P. Blondel DPNC, Genève, Switzerland
	Ionization Cooling is the only practical solution to preparing high brilliance muon beams for a neutrino factory or muon collider. MICE is under development at the Rutherford Appleton Laboratory (UK). It is characterized by exquisite emittance determination by 6D measurement of individual particles, a cooling section comprising 23 MV of acceleration at 200 MHz and 3 liquid hydrogen absorbers totaling 1m of liquid hydrogen on the path of 140-240 MeV/c muons. The beam has already been commissioned successfully and first measurements of beam emittance performed. We are setting up for the final high precision emittance determination and the measurements of cooling in Li Hydrogen. The design offers opportunities to observe cooling with various absorbers and several optics configurations. Results will be compared with detailed simulations of cooling channel performance to ensure full understanding of the cooling process. Progress towards the full cooling experiment with RF re-acceleration will also be reported. Submitted by the MICE speakers bureau hoping for a contributed oral to be give by the spokesperson, prof. A. Blondel

TUPFI054	MICE Spectrometer Solenoid Magnetic Field Measurements	solenoid, simulation, shielding, factory	1466
	M.A. Leonova Fermilab, Batavia, USA
	The Muon Ionisation Cooling Experiment (MICE) is designed to demonstrate ionization cooling in a muon beam. Its goal is to measure a 10% change in transverse emittance of a muon beam going through a prototype Neutrino Factory cooling channel section with a 1% accuracy, corresponding to an absolute measurement accuracy of 0.1%. To measure the emittance, MICE uses two solenoidal spectrometers. The Spectrometer Solenoids are designed to have 4 T solenoidal fields, uniform at 3 per mil level in the tracking volumes. Analysis of magnetic field measurements of the Spectrometer Solenoids will be discussed, and results of extracting precise coil positions, angles, and coil radius measurements for input into magnet models will be presented.

TUPFI056	A Muon Collider as a Higgs Factory	collider, luminosity, factory, target	1472
	D.V. Neuffer, Y.I. Alexahin, M.A. Palmer Fermilab, Batavia, USA C.M. Ankenbrandt Muons. Inc., USA J.-P. Delahaye SLAC, Menlo Park, California, USA
	Because muons connect directly to a standard-model Higgs particle in s-channel production, a muon collider would be an ideal device for precision measurement of the mass and width of a Higgs-like particle, and for further exploration of its production and decay properties. The LHC has seen evidence for a 126 GeV Higgs particle, and a muon collider at that energy could be constructed. Parameters of a high-precision muon collider are presented and the necessary components and performance are described. An important advantage of the muon collider approach is that the spin precession of the muons will enable energy measurements at extremely high accuracy (E/E to 10^-6 or better). Extension to a higher-energy higher-luminosity device is also discussed.

TUPFI060	Complete Muon Cooling Channel Design and Simulations	beam-cooling, dipole, factory, simulation	1484
	C. Y. Yoshikawa, C.M. Ankenbrandt, R.P. Johnson Muons. Inc., USA Y.S. Derbenev, V.S. Morozov JLAB, Newport News, Virginia, USA D.V. Neuffer, K. Yonehara Fermilab, Batavia, USA
	Considerable progress has been made in developing promising subsystems for muon beam cooling channels to provide the extraordinary reduction of emittance required for an Energy-Frontier Muon Collider, but lacks an end-to-end design. Meanwhile, the recent discovery of a Higgs-like boson has created interest in the High Energy physics community for a Higgs Factory to investigate its properties and verify whether it is Standard Model or beyond. We present principles and tools to match emittances between and within muon beam cooling subsystems that may have different characteristics. The Helical Cooling Channel (HCC), which combines helical dipoles and a solenoid field, allows a general analytic approach to guide designs of transitions from one set of cooling channel parameters to another. These principles and tools will be applied to design a complete cooling channel that would be applicable to a Higgs Factory and an Energy Frontier Muon Collider.

TUPFI065	Muon Ionization Cooling Experiment Step VI	cavity, coupling, vacuum, status	1499
	D. Rajaram Illinois Institute of Technology, Chicago, Illinois, USA P. Snopok IIT, Chicago, Illinois, USA
	The Muon Ionization Cooling Experiment (MICE) is a demonstration experiment to prove the viability of cooling a beam of muons for use in a Neutrino Factory and Muon Collider. The ultimate Step VI configuration of the MICE cooling channel, a section of the one proposed in the Neutrino Factory Study II, will demonstrate a 10% reduction in transverse beam emittance measured at the level of 1%. This requires measuring emittance to 0.1%. This measurement will be made using all beam line elements present in the MICE Step IV configuration with the addition of two low-Z absorber modules and two RF-Coupling Coil (RFCC) modules. The RFCC modules each contain four normal-conducting low frequency (201 MHz) RF cavities with a guiding magnetic field provided by a large diameter coupling coil. Each of these cavities will require approximately 1 MW of RF power in a 1 ms pulse at a rate of 1 Hz. The experiment can explore a variety of combinations of momentum, beta function, magnetic field flip or non-flip configurations that will prove precious in the design of future cooling channels. The current status and progress toward Step VI are discussed.

TUPFI066	Muon Ionization Cooling Experiment Step VI	solenoid, simulation, site, target	1502
	D. Rajaram Illinois Institute of Technology, Chicago, Illinois, USA P. Snopok IIT, Chicago, Illinois, USA
	In the Muon Ionization Cooling Experiment (MICE) the transverse emittance of the muon beam is reduced (muon cooling) by passing it through low-Z material, then through RF cavities to compensate for the energy loss. Transverse emittance reduction of the muon beam will be demonstrated for the first time in MICE Step IV configuration using liquid Hydrogen absorbers as well as a variety of solid absorbers. Current status and efforts towards Step IV are summarized, including hardware fabrication and testing, Monte Carlo simulations, track reconstruction algorithms.

TUPFI069	Influence of Proton Beam Emittances on Particle Production off a Muon Collider Target	target, proton, collider, factory	1511
	X.P. Ding, D.B. Cline UCLA, Los Angeles, California, USA J.S. Berg, H.G. Kirk, H. K. Sayed BNL, Upton, Long Island, New York, USA V.B. Graves ORNL, Oak Ridge, Tennessee, USA K.T. McDonald PU, Princeton, New Jersey, USA N. Souchlas, R.J. Weggel Particle Beam Lasers, Inc., Northridge, California, USA
	Funding: Work supported in part by US DOE Contract NO. DE-AC02-98CHI10886. A free-mercury-jet or a free-gallium-jet is considered for the pion-production target at a Muon Collider or Neutrino Factory. Based on a simple Gaussian incident proton beams with an infinitely large Courant-Snyder β parameters, we have previously optimized the geometric parameters of the target to maximize particle production initiated by incoming protons with kinetic energies (KE) between 2 and 16 GeV by using the MARS15 code. In this paper, we extend our optimization to focused proton beams with various transverse emittances. For the special cases of proton beams with emittances of 2.5, 5 or 10 μm-rad and a kinetic energy of 8 GeV, we optimized the geometric parameters of the target: the radius of the proton beam, the radius of the liquid jet, the crossing angle between the jet and the proton beam, and the incoming proton beam angle. We also study the influence of a shift of the beam focal point relative to the intersection point of the beam and the jet.

TUPFI078	Measurement of the Total Cross Section of Uranium-uranium Collisions at a Center-of-mass Energy of 192.8 GeV per Nucleon-pair	ion, beam-losses, luminosity, scattering	1529
	W. Fischer, A.J. Baltz, M. Blaskiewicz, K.A. Drees, D.M. Gassner, Y. Luo, M.G. Minty, P. Thieberger, M. Wilinski BNL, Upton, Long Island, New York, USA I.A. Pshenichnov RAS/INR, Moscow, Russia
	Funding: Work supported by U.S. DOE under contract No DE-AC02-98CH10886 with the U.S. Department of Energy. Heavy ion cross sections totaling several hundred barns have been calculated previously for the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC). These total cross sections are more than an order of magnitude larger than the geometric ion-ion cross sections, primarily due to Bound-Free Pair Production (BFPP) and Electro-Magnetic Dissociation (EMD). Apart from a general interest in verifying the calculations experimentally, an accurate prediction of the losses created in the heavy ion collisions is of practical interest for the LHC, where some collision products are lost in cryogenically cooled magnets and have the potential to quench these magnets. In the 2012 RHIC run uranium ions collided with each other at a center-of-mass energy of 192.8 GeV per nucleon-pair with nearly all beam losses due to collisions. This allows for the measurement of the total cross section and a comparison with calculations.

TUPFI084	RHIC Polarized Proton Operation for 2013	lattice, polarization, injection, resonance	1544
	V.H. Ranjbar, L. A. Ahrens, E.C. Aschenauer, M. Bai, J. Beebe-Wang, M. Blaskiewicz, J.M. Brennan, K.A. Brown, D. Bruno, R. Connolly, T. D'Ottavio, K.A. Drees, Y. Dutheil, W. Fischer, C.J. Gardner, J.W. Glenn, X. Gu, M. Harvey, T. Hayes, H. Huang, R.L. Hulsart, A.I. Kirleis, J.S. Laster, C. Liu, Y. Luo, Y. Makdisi, G.J. Marr, A. Marusic, F. Méot, K. Mernick, R.J. Michnoff, M.G. Minty, C. Montag, J. Morris, S. Nemesure, P.H. Pile, A. Poblaguev, V. Ptitsyn, G. Robert-Demolaize, T. Roser, W.B. Schmidke, V. Schoefer, F. Severino, T.C. Shrey, D. Smirnov, K.S. Smith, D. Steski, S. Tepikian, D. Trbojevic, N. Tsoupas, J.E. Tuozzolo, G. Wang, M. Wilinski, K. Yip, A. Zaltsman, A. Zelenski, K. Zeno, S.Y. Zhang BNL, Upton, Long Island, New York, USA O. Eyser UCR, Riverside, California, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The 2013 operation of the Relativistic Heavy Ion Collider (RHIC) marks the second year of running under the RHIC II era. Additionally this year saw the implementation of several important upgrades designed to push the intensity frontier. Two new E-lenses have been installed, along with a new lattice designed for the E-lens operation. A new polarized proton source which generates about factor of 2 more intensity was commissioned as well as a host of RF upgrades from a new longitudinal damper, Landau cavity in RHIC to a new low level RF and new harmonic structure for the AGS. We present an overview of the challenges and results from this years run.

TUPFI086	A Tapered Six Dimensional Cooling Lattice for a Muon Collider	collider, lattice, simulation, focusing	1547
	D. Stratakis, R.C. Fernow, R.B. Palmer BNL, Upton, Long Island, New York, USA
	Designs for Neutrino Factories and Muon Colliders use ionization cooling to reduce the emittance of the muon beam prior to acceleration. Two lattices based on the original RFOFO ring design representing different configurations of the magnetic field are considered. One is with a flip magnetic field and one with a non-flip magnetic field configuration that is used to eliminate for possible space-charge effects. The details of the G4Beamline tracking studies of both channels are presented and compared to the independent ICOOL code.

TUPFI088	Space-charge Studies for Ionization Cooling Lattices	lattice, space-charge, collider, simulation	1553
	D. Stratakis, R.B. Palmer BNL, Upton, Long Island, New York, USA D.P. Grote LLNL, Livermore, California, USA
	Funding: This work is funded by US Dept. of Energy grant numbers DE AC02-98CH10886 Intense muon beams provide a promising solution to a variety of applications ranging from nanotechnology to nuclear detections systems and from medical sciences to high energy physics. Production of such intense beam requires the beam to be cooled and ionization cooling via particle matter interaction is considered one of the most practical methods. Here a theoretical and numerical study on space-charge effects on such ionization cooling channels is presented. We show that space-charge can strongly affect the design of muon cooling systems by limiting their minimum cooling rate. Space-charge compensation solutions are discussed and the minimum cooling emittance as a function of the beam charge and pulse width is identified.

TUPME001	Effect of Self-consistency on Space Charge Induced Beam Loss	resonance, simulation, space-charge, controls	1556
	G. Franchetti GSI, Darmstadt, Germany
	In long term storage space charge driven incoherent effect may lead to a slow beam diffusion that causes emittance growth and beam loss. However, when beam loss are relevant the full mechanism cannot be understood only driven by an incoherent effect. In this proceeding the issue of the self-consistency is discussed, and its impact presented for simplified examples and for the SIS100.

TUPME005	Preparations for Beam Tests of a CLIC Damping Wiggler Prototype at ANKA	wiggler, damping, target, storage-ring	1568
	A. Bernhard, E. Huttel, P. Peiffer KIT, Karlsruhe, Germany A.V. Bragin, N.A. Mezentsev, V.M. Syrovatin, K. Zolotarev BINP SB RAS, Novosibirsk, Russia P. Ferracin, D. Schoerling CERN, Geneva, Switzerland
	The Compact Linear Collider (CLIC) will require ultra-low emittance electron and positron beams. The targeted emittance will be achieved by radiative damping in the CLIC damping rings. For an efficient damping high-field short-period superconducting damping wigglers will be employed. In the conceptual design phase of CLIC, the basic layout of these wigglers has been elaborated at CERN. In the course of the CLIC technical feasibility studies a full-scale damping wiggler prototype will be installed and tested in the ANKA storage ring. The device is currently under design and construction at the Budker Institute of Nuclear Physics, Russia. Above the magnetic requirements, the main design challenges for the prototype are scalability –- particularly of the cooling concept –-, modularity and the capability of sustaining a high radiative heat load. The experiments at ANKA aim at a validation of the technical concepts applied to meet these requirements. Beyond that an extended experimental program on beam dynamics and alternative technical solutions is envisaged. This contribution gives an overview over the current status of the project and the further planning.

TUPME010	High-intensity and Low-emittance Upgrade of 7-GeV Injector Linac towards SuperKEKB	positron, linac, electron, laser	1583
	K. Furukawa, M. Akemoto, D.A. Arakawa, Y. Arakida, A. Enomoto, S. Fukuda, H. Honma, R. Ichimiya, N. Iida, M. Ikeda, E. Kadokura, K. Kakihara, T. Kamitani, H. Katagiri, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Miura, F. Miyahara, T. Mori, H. Nakajima, K. Nakao, T. Natsui, Y. Ogawa, S. Ohsawa, F. Qiu, M. Satoh, T. Shidara, A. Shirakawa, H. Sugimoto, T. Suwada, T. Takatomi, T. Takenaka, M. Tanaka, Y. Yano, K. Yokoyama, M. Yoshida, L. Zang, X. Zhou KEK, Ibaraki, Japan D. Satoh TIT, Tokyo, Japan
	After a decade of successful operation at KEKB a new electron/positron collider, SuperKEKB, is being constructed to commission within FY2014. It aims at a luminosity of 8 x 10³⁵ /s.cm², 40-times higher than that of KEKB, in order to study the flavor physics of elementary particles further, by mainly squeezing the beams at the collision point. The injector linac should provide high-intensity and low-emittance beams of 7-GeV electron and 4-GeV positron by newly installing a RF-gun, a flux concentrator, and a damping ring with careful emittance and energy management. It also have to perform simultaneous top-up injections into four storage rings by pulse-to-pulse beam modulations not to interfare between three facilities of SuperKEKB, Photon Factory and PF-AR. This paper describes the injector design decisions and present status of the construction.

TUPME014	Coherent Synchrotron Radiation Predicted at the SuperKEKB Damping Ring	damping, linac, vacuum, simulation	1595
	H. Ikeda, M. Kikuchi, K. Ohmi, K. Oide, D. Zhou KEK, Ibaraki, Japan
	The damping ring of SuperKEKB is under construction in order to inject low emittance positron beam into the main ring. We calculated the bunch lengthening and the energy spread caused by the longitudinal wake, which is dominated by the CSR wake field. The result was within the tolerance level.

TUPME019	Simulation for Control of Longitudinal Beam Emittance in J-PARC MR	injection, bunching, simulation, acceleration	1610
	M. Yamamoto, M. Nomura, A. Schnase, T. Shimada, F. Tamura JAEA/J-PARC, Tokai-mura, Japan E. Ezura, K. Hara, K. Hasegawa, C. Ohmori, A. Takagi, K. Takata, M. Toda, M. Yoshii KEK, Ibaraki, Japan
	The J-PARC MR receives a high intensity beam from the RCS. The designed longitudinal emittance of the RCS is 5 eVs, whereas the MR rf bucket has enough margin to accept up to 10 eVs. Although the RCS emittance can be increased by using PM method and a large emittance is desirable to increase the bunching factor and to avoid instability, it is difficult to receive such large emittance beam in the MR because of the MR kicker performance. We have performed the particle tracking simulation of longitudinal emittance control for enlarging the beam emittance by PM method and for keeping the bunching factor high using 2nd harmonic rf during the MR injection period.

TUPME021	Optimization Parameter Design of a Circular e⁺e⁻ Higgs Factory	luminosity, factory, synchrotron, collider	1616
	D. Wang, Y.W. An, J. Gao, H. Geng, Y.Y. Guo, Q. Qin, N. Wang, S. Wang, M. Xiao, G. Xu, S.Y. Xu IHEP, Beijing, People's Republic of China
	Funding: NSFC:11175192 In this paper we will show a genral method of how to make an optimized parameter design of a circular e⁺e⁻ Higgs Factory by using analytical expression of maximum beam-beam parameter and beamstrahlung beam lifetime started from given design goal and technical limitations. A parameter space has been explored.

TUPME022	Study on the Single Bunch Transverse Emittance Growth in BAPS	wakefield, lattice, vacuum, wiggler	1619
	J. Gao, D. Wang IHEP, Beijing, People's Republic of China
	Funding: Supported by the National Foundation of Natural Sciences Contract 11175192. Beijing Advanced photon Source (BAPS) is a proposed next synchrotron radiation facility which has much smaller transverse emittance after SSRF in China, with 5 GeV energy and 1.5 km circumference. In order to explore how small the transverse emittance we can get on BAPS, this paper studies the single bunch transverse emittance growth due to short range wakefield according to J. Gao’ theory. The mechanism of wakefield induced single bunch emittance is explained first and then the transverse emittance at the design beam current is estimated. Also, the tolerances for the transverse loss factor and the vacuum chamber misalignment (or the closed orbit distortion) are presented.

TUPME025	Calculation of the Equilibrium Parameters for the Compact Ring of TTX	photon, scattering, electron, storage-ring	1625
	H.S. Xu, W.-H. Huang, C.-X. Tang TUB, Beijing, People's Republic of China S.-Y. Lee IUCEEM, Bloomington, Indiana, USA
	Intra-Beam Scattering (IBS) can cause emittance growth in high intensity low energy beams. We study its effect on the compact low energy electron storage ring, proposed for Tsinghua Thomson Scattering X-ray source (TTX). For a single bunch with peak current at about 17A and re-entrant type normal conducting RF cavity with peak voltage at 15kV, the equilibrium horizontal and vertical emittances are 2.9 and 0.3 μm, and the rms momentum spread and bunch length are about 0.2%, and 23ps. In this paper, we report the methods and results of the IBS calculation.

TUPME030	Emittance Reconstruction from Measured Beam Sizes	coupling, simulation, optics, FEL	1640
	J. Giner Navarro, A. Faus-Golfe, J. Fuentes, J. Navarro, J. Resta IFIC, Valencia, Spain
	In this paper we analyze the projected emittance (2D) and the intrinsic emittance (4D) reconstruction method by using the beam size measurements at different locations. We have studied analytically the conditions of solvability of the systems of equations involved in this process and we have obtained some rules about the locations of the measurement stations to avoid unphysical results. Presently, simulations are being made to test the robustness of the algorithm in realistic scenarios with high coupling and measurement errors. The special case of a multi-OTR system in ATF2 is being studied in much detail. The results of these studies will be very useful to better determine the location of the emittance measurement stations in the diagnostic sections of Future Linear Colliders.

TUPME034	Experimental Studies for Future LHC Beams in the SPS	injection, optics, brightness, space-charge	1652
	H. Bartosik, T. Argyropoulos, T. Bohl, S. Cettour-Cave, J. Esteban Müller, W. Höfle, G. Iadarola, Y. Papaphilippou, G. Rumolo, B. Salvant, F. Schmidt, E.N. Shaposhnikova, H. Timko CERN, Geneva, Switzerland A.Y. Molodozhentsev KEK, Ibaraki, Japan
	The High Luminosity LHC (HL-LHC) project requires significantly higher beam intensity than presently accessible in the LHC injector chain. The aim of the LHC injectors upgrade project (LIU) is to prepare the CERN accelerators for the future needs of the LHC. Therefore a series of machine studies with high brightness beams were performed, assessing the present performance reach and identifying remaining limitations. Of particular concern are beam loading and longitudinal instabilities at high energy, space charge for beams with 50ns bunch spacing and electron cloud effects for beams with 25ns bunch spacing. This paper provides a summary of the performed studies, that have been possible thanks to the implementation of the SPS low gamma-transition optics.

TUPME042	The SPS as an Ultra-low Emittance Damping Ring Test Facility for CLIC	damping, wiggler, optics, target	1661
	Y. Papaphilippou, R. Corsini, L.R. Evans CERN, Geneva, Switzerland
	In view of the plans for a future electron/positron linear collider based on the CLIC technology, an ultra-low emittance damping ring test facility is proposed, using the CERN SPS. Optics modification, required wiggler length and characteristics, energy and RF parameters are presented in order to reach CLIC performance requirements, including the effect of Intrabeam Scattering. Considerations about the necessary injected beam characteristics, its production and transfer through the existing CERN accelerator complex are also discussed.

TUPME045	Turn-by-turn Measurements in the KEK-ATF	synchrotron, damping, injection, betatron	1664
	Y. Renier, Y. Papaphilippou, R. Tomás, M. Wendt CERN, Geneva, Switzerland N. Eddy Fermilab, Batavia, USA K. Kubo, S. Kuroda, T. Naito, T. Okugi, N. Terunuma, J. Urakawa KEK, Ibaraki, Japan
	The ATF damping ring has been upgraded with new read-out electronics for the beam position monitors (BPM), capable to acquire the beam orbits on a turn-by-turn basis, as well as in a high resolution averaging mode. The new BPM system allows to improve optic corrections and to achieve an even smaller vertical emittance (<2pm). Experimental results are presented based on turn-by-turn beam orbit measurements in the ring, for estimating the beta functions and dispersion along the lattice. A fast method to measure spectral line amplitude in a few turns is also presented, including the evaluation of chromaticity.

TUPME046	Performance of SPS Low Transition Energy Optics for LHC Ion Beams	optics, ion, scattering, space-charge	1667
	F. Antoniou, G. Arduini, H. Bartosik, T. Bohl, S. Cettour Cave, K. Cornelis, D. Manglunki, Y. Papaphilippou CERN, Geneva, Switzerland
	An optics with low transition energy has been developed in the SPS for removing intensity limitations of the LHC proton beam and has become operational towards the second part of the 2012 LHC proton run. This optics was also used for filling the LHC with lead ions during the p/Pb run of the beginning of 2013. The impact of this optics in the performance of the LHC ion beam is studied here, especially with respect to collective effects, at the SPS injection energy. In particular, the potential gain of the increased beam sizes provided by this optics, with respect to losses and emittance blow up due to space-charge and Intrabeam Scattering (IBS) is evaluated. The measured lifetime is compared with the one provided by the Touschek effect and its interplay with RF noise is studied. The models are supported by measurements in the SPS and in the LHC flat bottom.

TUPME048	Imperfection Tolerances for On-line Dispersion Free Steering in the Main Linac of CLIC	linac, wakefield, quadrupole, simulation	1673
	J. Pfingstner, A. Latina, D. Schulte CERN, Geneva, Switzerland
	Long-term ground motion misaligns the elements of the main linac of CLIC over time. Especially the misaligned quadrupoles create dispersion and hence the beam quality is decreased gradually due to an effect called chromatic dilution. Over longer time periods, orbit feedback systems are not capable to fully recover the beam quality and have to be supplemented by dispersion correction algorithms. In this paper, such and dispersion correction algorithm is presented, which is an extended version of the well-known dispersion free steering algorithm. This extended algorithm can recover the beam quality over long time scaled without stopping the accelerator operation (on-line). Tolerances for different imperfections of the system have been identified and a strong sensitivity to the resolution of the wake field monitors of the main linac accelerating structures has been identified. This problem can be mitigated by using a local excitation scheme as will be shown in this work.

TUPME050	Performance Comparison of Different System Identification Algorithms for FACET and ATF2	kicker, simulation, linac, alignment	1679
	J. Pfingstner, A. Latina, D. Schulte CERN, Geneva, Switzerland
	Good system knowledge is an essential ingredient for the operation of modern accelerator facilities. For example, beam-based alignment algorithms and orbit feedbacks rely strongly on a precise measurement of the orbit response matrix. The quality of the measurement of this matrix can be improved over time by statistically combining the effects of small system excitations with the help of system identification algorithms. These small excitations can be applied in a parasitic mode without stopping the accelerator operation (on-line). In this work, different system identification algorithms are used in simulation studies for the response matrix measurement at ATF2. The results for ATF2 are finally compared with the results for FACET, latter originating from an earlier work.

TUPME055	Strawman Optics Design for the CERN LHeC ERL Test Facility	linac, optics, lattice, electron	1694
	A. Valloni, O.S. Brüning, R. Calaga, E. Jensen, M. Klein, R. Tomás, F. Zimmermann CERN, Geneva, Switzerland S.A. Bogacz, D. Douglas JLAB, Newport News, Virginia, USA
	In preparation for a future Large Hadron electron Collider (LHeC) at CERN, an ERL test facility is foreseen as a test bed for SRF development, cryogenics, and advanced beam instrumentation, as well as for studies of ERL-specific beam dynamics. The CERN ERL test facility would comprise two linacs, each consisting of 4 superconducting 5-cell cavities at 802 MHz, and two return arcs on either side. With an RF voltage of 75 MeV per linac a final electron energy of about 300 MeV is reached. The average beam current should be above 6 mA to explore the parameter range of the future LHeC. In this paper we present a preliminary optics layout.

TUPME056	3.5 GeV Superconducting Stacking Ring for Compton Based Polarized Positrons Source of CLIC	positron, injection, damping, synchrotron	1697
	E.V. Bulyak, P. Gladkikh, A.A. Kalamayko NSC/KIPT, Kharkov, Ukraine T. Omori, J. Urakawa, K. Yokoya KEK, Ibaraki, Japan L. Rinolfi, F. Zimmermann CERN, Geneva, Switzerland
	This paper describes 3.5 GeV superconducting storage ring dedicated to positron accumulation as part of a polarized positron source for CLIC, based on Compton scattering in a Compton storage ring. The superconducting stacking ring can provide a synchrotron damping time of order 250 microseconds. Together with combined injection scheme in the longitudinal and transverse plane, such a ring may solve the problem of accumulating a positron beam with efficiency close to 95 % and with the beam intensity required for CLIC.

TUPME059	Collisional Effects in Particle-in-Cell Beam-Beam Simulations	simulation, collider, luminosity, proton	1700
	S. Paret, J. Qiang LBNL, Berkeley, California, USA
	Funding: This work was partially supported by the U.S. LARP and the NERSC of the U.S. Department of Energy under contract No. DE-AC02-05CH11231. Self-consistent particle tracking simulations (strong-strong) can be used to investigate the deterioration of colliding beams in a storage ring. However, the use of a small number of macroparticles copmared to the real number of particles magnifies the collisional effects and causes numerical noise. In particular, predictions of the emittance lifetime suffer from this numerical noise. In order to produce usable emittance predictions, the contribution of numerical noise to the simulated emittance growth has to be known. In this paper, we apply a diffusion model to strong-strong beam-beam simulations to study the numerical noise driven emittance growth. The scaling of emittance growth with numerical and physical parameters is discussed.

TUPME060	Tune Studies with Beam-Beam Effects in LHC	resonance, simulation, luminosity, collider	1703
	S. Paret, J. Qiang LBNL, Berkeley, California, USA R. Alemany-Fernandez, X. Buffat, R. Calaga, K. Cornelis, M. Fitterer, R. Giachino, W. Herr, A. Macpherson, G. Papotti, T. Pieloni, S. Redaelli, F. Roncarolo, M. Schaumann, R. Suykerbuyk, G. Trad CERN, Geneva, Switzerland R. Miyamoto ESS, Lund, Sweden
	Funding: This work was partially supported by the U.S. LARP and the NERSC of the U.S. Department of Energy under contract No. DE-AC02-05CH11231. In high brightness colliders, the tune spread due to the collisions has a significant impact on the quality of the beams. The impact of the working point on emittance growth and beam lifetime has been observed in beam experiments in LHC. Strong-strong beam-beam simulations that were accomplished to better understand such observations are shown. Compared to experiments, wide ranged parameter scans can be done easily. Tune footprints and scans of the emittance growth obtained from simulations are discussed. Three cases are considered: Very high intensity, moderate intensity and collisions with separated beams.

TUPME061	Emittance Growth with Crab Cavity and Damper Noise in LHC	simulation, pick-up, resonance, damping	1706
	S. Paret, J. Qiang LBNL, Berkeley, California, USA
	Funding: This work was partially supported by the U.S. LARP and the NERSC of the U.S. Department of Energy under contract No. DE-AC02-05CH11231. Strong-strong beam-beam simulations are employed to investigate the noise sensitivity of the emittance in the future High Luminosity (HL)-LHC. Noise in the accelerator causes fluctuations of the bunch centroids at the interaction points (IPs) which cause emittance growth for large beam-beam parameters. Two noise sources are examined: Crab cavities and the transverse damper. The damper noise is adjusted to bring simulations in agreement with an emittance measurement in a past LHC run. Results from simulations with HL-LHC beam parameters using different noise levels, damper gains and working points are discussed.

TUPME066	CESR Low Emittance Upgrade with Combined Function Bends	wiggler, quadrupole, damping, focusing	1718
	D. L. Rubin, Y. Li, A.A. Mikhailichenko, S. Wang CLASSE, Ithaca, New York, USA
	Funding: Work supported by the National Science Foundation and Department of Energy under contract numbers PHY-1002467, DMR-0936384 and DE-SC0006505 The Cornell Electron Storage Ring is the laboratory for the CESR Test Accelerator damping ring R&D program, and the source of x-rays for CHESS. A peculiarity of the layout of the storage ring is that horizontal emittance is generated predominantly by the strong bends in the sextant of the ring that was designed with a long straight to accommodate the interaction region required for operation as an electron-positron collider. By reconfiguring that single sextant we reduce the emittance by 60% to 20 nm-rad at 5.3 GeV for x-ray production and with damping wigglers to 1.3 nm-rad at 2.1 GeV for investigations of low emittance phenomena. The 35 meter radius of curvature, 3.2 meter long dipoles are refitted as combined function (vertically focusing) magnets to create simple achromats. The layout can accommodate six, 3 meter long undulators, in addition to the six existing superconducting damping wigglers. With reduced horizontal emittance and energy spread, the reconfiguration enhances the sensitivity of CESR to the emittance diluting effects that are the subject of the CesrTA study. Capability of the x-ray source is significantly improved with six new undulator beam lines.

TUPWA003	Beam Based Magnet Alignment for Emittance Coupling Minimization	sextupole, quadrupole, storage-ring, coupling	1724
	R.T. Dowd, G. LeBlanc, Y.E. Tan ASCo, Clayton, Victoria, Australia K.P. Wootton The University of Melbourne, Melbourne, Australia
	Magnet misalignments give rise to field terms which can cause coupling between the horizontal and vertical beam motion and therefore emittance coupling. A series of beam based measurements have been developed at the Australian Synchrotron to accurately quantify quadrupole and sextupole alignments errors which cause coupling and where possible, correct them. Results showing an reduction in emittance coupling due to realignments of magnets based on these measurements will be presented. Limitations and general applicability of this method will also be discussed.

TUPWA004	Advanced Considerations for Designing Very High-intensity Linacs through Novel Methods of Beam Analysis, Optimization, Measurement & Characterisation	linac, space-charge, extraction, rfq	1727
	P.A.P. Nghiem, N. Chauvin, D. Uriot CEA/DSM/IRFU, France W. Simeoni CEA/IRFU, Gif-sur-Yvette, France
	Research in fundamental physics, nuclear physics or advanced materials, requires linear accelerators as irradiation sources with higher and higher beam intensity. In such machines, not only high beam power but also high space charge are the major challenges. This double concern often induces conflicting issues, which should be overcome from the accelerator design stage. It progressively appears that the usual methods are no more sufficient. Even new concepts are to be invented. With mega-watt beams, losses and also micro-losses must be minimised while with very strong space charge, few room can be reserved for beam diagnostics. New strategies for design and tuning are to be carried out. The beam itself can no more be described only by its classical values like emittance and Twiss parameters. Core and halo parts should be instead precisely defined and kept under surveillance. The beam phase space distribution itself becomes determinant, which is very far from waterbag or gaussian distributions. This paper aims at proposing new considerations for very high-intensity linacs while recalling the usual ones, from designing and tuning methods to beam definitions and characterisations.

TUPWA007	Method and Results of Systematic Beam Matching to a Periodic DTL	DTL, resonance, focusing, quadrupole	1733

Paper

Title

Other Keywords

Page

MOYAB101

The First Years of LHC Operation for Luminosity Production

luminosity, proton, injection, feedback

6

M. Lamont
CERN, Geneva, Switzerland

A summary of the first 3 years of LHC operation is presented with a discussion on the performance ramp-up, operation efficiencies and system reliability. The main contributory factors to peak and integrated luminosity performance are outlined.

Slides MOYAB101 [12.139 MB]

MOPEA004

Beam Lifetime in the ASTRID and ASTRID2 Synchrotron Light Sources: Excitations and Vacuum Dependences

synchrotron, vacuum, ion, electron

67

J.S. Nielsen, N. Hertel, S.P. Møller
ISA, Aarhus, Denmark

The beam lifetime is a very important parameter for synchrotron light sources without top-up, and sometimes more important than the lowest possible vertical beam emittance. At the ASTRID synchrotron light source, we have for many years routinely applied a phase modulation of the accelerating RF field, together with a vertical excitation of the beam at the first vertical betatron frequency. These two effects increase the beam lifetime from about 3 hours to more than 100 hours at 150 mA. Lifetime measurements as function of modulation and excitation parameters will be presented. Additionally, measurements of the beam lifetime in ASTRID and ASTRID2 as function of vacuum pressure will be presented.

MOPEA007

Study of Lower Emittance Optics Using Multi-Bend-Achromat Lattice at SOLEIL

dipole, optics, lattice, quadrupole

76

R. Nagaoka, P. Brunelle, X. Gavaldà, M. Klein, A. Loulergue, A. Nadji, L.S. Nadolski, M.-A. Tordeux
SOLEIL, Gif-sur-Yvette, France

In the framework of a future upgrade of the SOLEIL 354 m long and 2.75 GeV storage ring, a series of lattice studies has been launched to aim at reducing by an order of magnitude the current 4 nm.rad horizontal emittance. In this exercise, the main constraint imposed is to leave all the existing 24 straight sections for insertion devices untouched. In the previous study (presented at IPAC 2012), the possibility of using superbends and exploiting their longitudinal dipole field variation was pursued in lowering the emittance, finding solutions with a horizontal emittance in the sub nanometer range. In the present study, the use of MBA (Multi-Bend-Achromat) lattice is explored, which is widely recognized today as the optimal lattice in reaching an ultra-low emittance. The study aims to clarify the adaptability of the MBA and the range of attainable emittance for the SOLEIL ring, in view particularly of the short straight sections existing in half of the original DBA cells in between the dipoles. The possibility of combining the previously obtained superbend solutions with the MBA lattice is also examined.

MOPEA008

A Low-Emittance Lattice for the ESRF

lattice, sextupole, dipole, injection

79

L. Farvacque, N. Carmignani, J. Chavanne, A. Franchi, G. Le Bec, S.M. Liuzzo, B. Nash, T.P. Perron, P. Raimondi
ESRF, Grenoble, France

In the framework of its upgrade, the ESRF is looking at a new lattice for replacing the present Double Bend Achromat structure. This new lattice must have the same length and periodicity as the present one and keep the beamline source points unchanged. We will describe our design of an 844 m long lattice based on a 7-bend achromat. It is optimized for minimising the operation costs, in particular the wall-plug power, provides a large dynamic aperture allowing off-axis injection with the present ESRF injector, and gives an horizontal emittance of less than 200 pm at 6 GeV, thus considerably improving the brilliance and transverse coherence of the ESRF.

MOPEA009

ESRF Operation and Upgrade Status

undulator, storage-ring, booster, permanent-magnet

82

J.-L. Revol, J.C. Biasci, J-F. B. Bouteille, F. Ewald, L. Farvacque, A. Franchi, G. Gautier, L. Goirand, M. Hahn, L. Hardy, J. Jacob, J.M. Koch, M.L. Langlois, G. Lebec, J.M. Mercier, T.P. Perron, E. Plouviez, P. Raimondi, K.B. Scheidt, V. Serrière
ESRF, Grenoble, France

The European Synchrotron Radiation Facility (ESRF) is presently midway through the Upgrade Programme Phase I (2009-2015), which concerns its infrastructure, beamlines and X-ray source. This paper reports on the present operation performance of the source, highlighting the more recent developments. In this context, 8 insertion device straight sections have been lengthened from five to six metres; two of them operating with canted undulators. The lattice of one cell has been modified for a further increase to 7 metres allowing the test of a mini beta optics and latter the distribution of cavities. A second cryogenic permanent magnet undulator has been completed, which gives a factor of more than 2 in flux at high energy. The booster klystron-based radio frequency transmitter has been replaced by high power solid state amplifiers. Out of three prototypes of HOM damped cavities working at room temperature which have been received and tested, one has been successfully commissioned with beam. Subsequent to the upgrade of the beam position monitor system, a new orbit feedback has substantially reduced the orbit distortion induced by ID gap motions.

MOPEA017

Electron Cooling of Heavy Ions Interacting with Internal Target at HESR of FAIR

electron, target, ion, scattering

103

T. Katayama, M. Steck
GSI, Darmstadt, Germany
R. Maier, D. Prasuhn, H. Stockhorst
FZJ, Jülich, Germany

The High Energy Storage Ring (HESR) is designed and optimized to accumulate and store the anti-proton beam for the internal target experiment. The recent demand of atomic physics has impacted to use the HESR facility also as the storage ring of bare heavy ions. In this concept the bare heavy ions are injected at 740 MeV/u from the Collector Ring where the ions are well stochastically cooled to be matched with HESR ring acceptance. In the HESR the 2 MeV electron cooler is prepared with the maximal electron current of 3 A and the cooling length of 2.7 m. The electron cooling process of typically ²³⁸U⁹²⁺ beam is simulated for the Hydogen and Xe internal target with simultaneous use of barrier voltage to compensate the mean energy loss caused by the interaction with internal target. In the present report the detailed simulation results of 6D phase space obtained by the particle tracking code are precisely discussed.

MOPEA023

Lattice Design for the ILSF Booster Synchrotron

booster, sextupole, damping, quadrupole

121

E. Ahmadi, H. Ghasem, F. Saeidi
ILSF, Tehran, Iran
H. Ghasem
IPM, Tehran, Iran

ILSF booster synchrotron is a full energy 3GeV injector with the circumference of 192m will be housed in a separate tunnel from storage ring. In order to keep low the emittance, a theoretical minimum emittance lattice in which the dipoles and quadrupoles have sextupole component has been considered for the booster. In this paper, the lattice concept and main features of the booster will be reported. The variation of emittance and beam size during booster ramping is also investigated. Finally the effect of existed eddy current on the chromaticity and dynamic aperture will be presented.

MOPEA027

New Optics with Emittance Reduction at the SPring-8 Storage Ring

optics, photon, injection, sextupole

133

Y. Shimosaki, K. Fukami, K.K. Kaneki, K. Kobayashi, M. Masaki, C. Mitsuda, T. Nakamura, T. Nakanishi, H. Ohkuma, M. Oishi, M. Shoji, K. Soutome, S. Takano, M. Takao
JASRI/SPring-8, Hyogo-ken, Japan

The machine tuning of a new optics is in progress at the SPring-8 storage ring, in order not only to provide brilliant photons for current users but also to study a strategy of a lattice design and a tuning scenario for the upgrade project SPring-8 II. The natural emittance is reduced to 2.4 nmrad from the present value of 3.4 nmrad without any change of magnet positions. The flux density 1.3 times higher than the present was observed at the diagnostics beamline. The nominal injection efficiency of the order of 80 % has been achieved (the present: 92 %) by correcting the error of the optics function, by adjusting the strength of the injection magnets and by optimizing the sextupole magnetic fields. The beam lifetime was 13 h at 1 mA / bunch (the present: 22 h), and the momentum aperture estimated from the measurement of the Touschek lifetime was 2.3 % (the present: 2.8 %). Though these are tolerable to the user operation, further optimization of the sextupoles is ongoing. After verifying the photon beam performance at beamlines, this new optics will be applied to the user operation. The optics design and its beam performance will be presented in detail.

MOPEA032

Installation Status of Deuteron Injector of IFMIF Prototype Accelerator in Japan

neutron, rfq, alignment, simulation

148

H. Shidara, J. Knaster
IFMIF/EVEDA, Rokkasho, Japan
D. Bogard, N. Chauvin, P. Girardot, R. Gobin, F. Harrault, D. Loiseau, P.A.P. Nghiem, A. Roger, F. Senée
CEA/DSM/IRFU, France
L. Semeraro
F4E, Barcelona, Spain

The International Fusion Materials Irradiation Facility (IFMIF) will generate a neutron irradiation field with the spectrum simulating the fusion D-T neutrons (14 MeV) to qualify suitable materials for fusion power plants. The IFMIF accelerator facility provides two CW / 40 MeV / 125 mA deuteron beams to the IFMIF Lithium target facility. In the Engineering Validation and Engineering Design Activities phase, the concept of IFMIF is validated with a single CW / 9 MeV / 125 mA deuteron accelerator prototype under construction in JAEA/Rokkasho. The injector part has been designed, constructed and successfully tested by CEA/Saclay. The ECR ion source produces a deuteron beam of 140 mA at 100 keV. In spring 2013, the injector will be delivered and re-installed on the Rokkasho site. This paper will focus on the detailed plan of the injector’s re-assembly as well as on the re-commissioning. Further possible improvements are discussed in order to achieve reliable operation.

MOPEA042

Research on the Design and Simulation of the CSRE Stochastic Cooling System

sextupole, pick-up, target, simulation

169

X.J. Hu, H. Jia, Y.J. Yuan, X.H. Zhang
IMP, Lanzhou, People's Republic of China

Stochastic cooling by the use of a feedback system, aims at cooling of secondary particles or particles with large emittance or momentum spread. My research is mainly on the simulation of horizontal and longitudinal stochastic cooling process. The purpose of my work is to obtain the optimum parameters for stochastic cooling, according the actual accelerator lattice. Pickup and preamplifier are already installed on the CSRe, and preliminary results are get.

MOPEA045

Performance Optimization and Upgrade of the SSRF Storage Ring

storage-ring, optics, injection, cavity

178

Z.T. Zhao, B.C. Jiang, Y.B. Leng, S.Q. Tian, L. Yin, W.Z. Zhang
SINAP, Shanghai, People's Republic of China

The SSRF storage ring achieved its design performance goal in 2008, in the following years its performance was optimized and improved, including implementing top-up operation and low emittance lattice configuration as well as other attempts like fast orbit feedback and low alpha mode. In order to meet the requirements of accommodating more beamlines and high demanding performance in its phase-II beamline project, the SSRF storage ring is being upgraded with a design based on superbend based lattice and a third harmonic RF cavity system. This paper presents the main optimization works and the upgrade design considerations on the SSRF storage ring performance.

MOPEA057

Studies of the Electron Beam Lifetime at MAX III

scattering, cavity, electron, vacuum

208

A. Hansson, Å. Andersson, J. Breunlin, G. Skripka, E.J. Wallén
MAX-lab, Lund, Sweden

MAX III is a 700 MeV 3rd generation synchrotron light source located at the MAX IV Laboratory in Sweden. The lifetime in the storage ring is lower than originally envisaged. From vertical scraper measurements the lifetime contributions at 300 mA stored current have been determined. The lifetime is mainly limited by the Touschek lifetime, which is lower than its design value, whereas the vacuum lifetime is close to the expected value. The low Touschek lifetime is explained by a lower than design emittance ratio and momentum acceptance in the storage ring.

MOPEA060

Design of Low Momentum Compaction Lattices for the TPS Storage Ring

lattice, sextupole, injection, dipole

217

C.-C. Kuo, H.-J. Tsai
NSRRC, Hsinchu, Taiwan

The nominal bunch length is around 10 ps rms in the Taiwan Photon Source (TPS), which is currently under construction. To further reduce bunch length to a few ps rms range, low momentum compaction factor configurations (low alpha), i.e., quasi-isochronous machines, are designed. The beam dynamics issues of the TPS low alpha lattices are reported.

MOPEA066

Investigation and Test of the Possibility of Reducing the Emittance of the Diamond Storage Ring

optics, lattice, wiggler, injection

234

B. Singh, M. Apollonio, R. Bartolini, E.C. Longhi
Diamond, Oxfordshire, United Kingdom
R. Bartolini, T. Pulampong
JAI, Oxford, United Kingdom

Theoretical and experimental studies have been carried out at the Diamond Light Source to assess the possibility of reducing the emittance of the existing storage ring by means of a change to the optics. The optics solutions obtained so far using a Multi Objective Genetic Algorithm (MOGA) increase the dispersion and the horizontal beta function in the straight section. While the emittance can be reduced to 2.1 nm this optics is limited by the operation of high field superconducting wiggler devices. In this report we present details of the new optics and present results of practical tests. We also compare the theoretical emittance growth due to a wiggler in a dispersive region with test results.

MOPEA067

Ultra-low Emittance Upgrade Options for Third Generation Light Sources

lattice, dipole, resonance, dynamic-aperture

237

R. Bartolini
Diamond, Oxfordshire, United Kingdom
T. Pulampong
JAI, Oxford, United Kingdom

The increasing efforts in the synchrotron light sources community toward the design of a diffraction limited source at multi-keV photon energy have eventually stimulated the existing facilities to investigate possible upgrade paths to higher photon brightness and lower emittances to maintain their competitiveness within the users’ community. We present a possible option for upgrading 3rd generation light sources based on a rebiuld of the arcs with MBA cells, using diamond as an example. Emphasis is given to the AP desing issues with a view to minimal changes to the machine layout, contained cost and minimal downtime

MOPEA071

Operating the Diamond Storage Ring with Reduced Vertical Emittance

feedback, coupling, target, storage-ring

249

I.P.S. Martin, M.G. Abbott, M. Apollonio, R. Bartolini, D. Hickin
Diamond, Oxfordshire, United Kingdom
R. Bartolini
JAI, Oxford, United Kingdom

In a synchrotron radiation light source, a reduction in vertical emittance can potentially increase the source brightness, reduce the spot size for microfocus beam lines or increase the vertical transverse coherence of the photon beam. With this aim, the target vertical emittance for the Diamond storage ring has been recently reduced from 27pm.rad to 8pm.rad (0.3% coupling). In this paper we discuss the main impacts of this reduction, along with the steps that have been taken to stabilise the coupling at the new value.

MOPEA072

Recent Improvement of the APS Booster Synchrotron

booster, lattice, injection, synchrotron

252

C. Yao, R. Laird, V. Sajaev, N. Sereno, H. Shang, J. Wang, S. Xu
ANL, Argonne, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-ACO2-O6CH11357.
The APS booster injector is a 7-GeV electron synchrotron. Several improvements have been implemented in the booster area, including the development of the 92-nm low emittance lattice, upgrading the ramp current readback ADC, and development of a new firing card for the main ramp supplies. Recently we have completed the commissioning of the low emittance lattice and it is now APS operational lattice. Combined with improvement in the optimization in the storage ring lattice and injection, we have achieved close to 100% storage ring injection efficiency. This report presents the improvements and measured beam parameters and the measured performance of the ramp control.

MOPEA074

Lattice Studies for a Potential Soft X-ray Diffraction Limited Upgrade of the ALS

lattice, brightness, scattering, injection

258

C. Steier, J.M. Byrd, R.W. Falcone, S.D. Kevan, D. Robin, C. Sun, H. Tarawneh, W. Wan
LBNL, Berkeley, California, USA

Funding: The Advanced Light Source is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
The Advanced Light Source (ALS) at Berkeley Lab has seen many upgrades over the years, keeping it one of the brightest sources for soft x-rays worldwide. Recent developments in magnet technology and lattice design (multi bend achromat lattices) appear to open the door for very large further increases in brightness, particularly by reducing the horizontal emittance, even within the space constraints of the existing tunnel. Initial studies yielded candidate lattices which approach the soft x-ray diffraction limit (around 2 keV) in both planes within the ALS footprint.

MOPEA075

Completion of the Brightness Upgrade of the ALS

lattice, brightness, insertion, sextupole

261

C. Steier, B.J. Bailey, K. Berg, A. Biocca, A.T. Black, P.W. Casey, D. Colomb, R.F. Gunion, N. Li, A. Madur, S. Marks, H. Nishimura, G.C. Pappas, K.V. Petermann, G.J. Portmann, S. Prestemon, A.W. Rawlins, D. Robin, S.L. Rossi, T. Scarvie, D. Schlueter, C. Sun, H. Tarawneh, W. Wan, E.C. Williams
LBNL, Berkeley, California, USA
C. Chen, J. Jin, Y.M. Wen, J. Wu, L. Yin, J.D. Zhang, Q.G. Zhou
SINAP, Shanghai, People's Republic of China

Funding: The Advanced Light Source is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
The Advanced Light Source (ALS) at Berkeley Lab remains one of the brightest sources for soft x-rays worldwide. A multiyear upgrade of the ALS is underway, which includes new and replacement x-ray beamlines, a replacement of many of the original insertion devices and many upgrades to the accelerator. The accelerator upgrade that affects the ALS performance most directly is the ALS brightness upgrade, which reduced the horizontal emittance from 6.3 to 2.0 nm (2.5 nm effective). Magnets for this upgrade were installed starting in 2012 followed by a transition to user operations with 2.0 nm emittance in spring 2013.

MOPEA079

Improving Emittances in Existing Storage Rings by Defocusing Dipoles

dipole, quadrupole, optics, lattice

270

C.E. Mayes, L. Gupta, G.H. Hoffstaetter, V.O. Kostroun, A.A. Mikhailichenko
CLASSE, Ithaca, New York, USA

Designs for ultimate storage rings typically employ two strategies to lower the emittances: 1) adding more bending magnets, and 2) using only focusing quadrupole magnets, with additional defocusing in the bending magnets. In an existing storage ring, the first strategy is precluded because the number of bends is typically fixed, but the second strategy could be used at modest expense. With the CESR storage ring as an example, we show how this is possible and propose an optics that reduces its emittance by more than a factor of 20. Furthermore, such an upgrade would could be installed incrementally without any long dark-time period.

MOPFI002

Results from Beam Commissioning of an SRF Plug-gun Cavity Photoinjector

cavity, laser, cathode, gun

282

M. Schmeißer, R. Barday, A. Burrill, A. Jankowiak, T. Kamps, J. Knobloch, O. Kugeler, P. Lauinger, A. Neumann, J. Völker
HZB, Berlin, Germany
P. Kneisel
JLAB, Newport News, Virginia, USA
R. Nietubyć
NCBJ, Świerk/Otwock, Poland
J.K. Sekutowicz
DESY, Hamburg, Germany
I. Will
MBI, Berlin, Germany

Superconducting rf photoelectron injectors (SRF guns) hold the promise to deliver high brightness, high average current electron beam for future lightsources or other applications demanding continuous wave operation of an electron injector. This paper discusses results from beam commissioning of a hybrid Pb coated plug-gun Nb cavity based SRF photoinjector for beam energies up to 3 MeV at Helmholtz-Zentrum Berlin. Emittance measurements and transverse phase space characterization with solenoid-scan and pepperpot methods will be presented.

MOPFI004

The Injector Layout of BERLinPro

cathode, linac, cavity, gun

288

B.C. Kuske, M. Abo-Bakr, V. Dürr, A. Jankowiak, T. Kamps, J. Knobloch, P. Kuske, S. Wesch
HZB, Berlin, Germany

Funding: The Bundesministerium für Bildung und Forschung (BMBF) and the state of Berlin, Germany.
BERLinPro is an Energy Recovery Linac Project running since 2011 at the HZB in Berlin. The key component of the project is the 100mA superconducting RF photocathode gun under development at the HZB since 2010. Starting in 2016 the injector will go into operation providing 6 MeV electrons with an emittance well below 1mm mrad and bunches shorter than 4ps. 2017 the 50MeV linac will be set up and full recirculation is planned for 2018. The injector design including a dogleg merger has been finalized and is described in detail in this paper. Emphasis is laid on the final layout including collimators and diagnostics and performance simulations of two different gun cavities and first tolerance studies.

MOPFI012

Measurement of Adsorption Rates of Residual Gases for NEA-GaAs Surface

electron, cathode, ion, vacuum

306

M. Kuriki, H. Iijima, K. Miyoshi, K.U. Uchida
HU/AdSM, Higashi-Hiroshima, Japan

A GaAs photocathode activated the surface to negative-electron-affinity (NEA) is an important device for high-average-current electron accelerators such as a next-generation light source based on an energy recovery linac. The NEA surface is normally formed by a yo-yo technique in which cesium and oxygen are applied onto the surface alternately. Although the initial quantum efficiency is relatively larger than that of another cathode, the lifetime is shorter. The degradation with time elapsing even if the electron beam is not extracted is mainly caused by adsorption of residual gases in a vacuum chamber. We have evaluated the adsorption rates of various gases for the NEA surface by measuring the dark lifetime in sample gases such as hydrogen, carbon oxide and carbon dioxide.

MOPFI033

Commissioning Results and Progress of a Helium Injector for Coupled RFQ and SFRFQ Project at Peking University

ion, rfq, ion-source, cavity

357

J. Chen, J.E. Chen, S.L. Gao, Z.Y. Guo, Y.T. Luo, S.X. Peng, H.T. Ren, Z. Wang, Z.H. Wang, W.L. Xia, Y. Xu, A.L. Zhang, T. Zhang, J. Zhao
PKU, Beijing, People's Republic of China

At Peking University (PKU) a new helium injector for coupled radio frequency quadrupole(RFQ) and separated function radio frequency quadrupole(SFRFQ) within one cavity, so called as coupled RFQ & SFRFQ, was designed recently*. It will provide a 30keV 20mA He⁺ beam whose emittance is less than 0.15 π.mm.mrad for the accelerator. It is a combination of a 2.45GHz PKU PMECRIS (Permanent Magnet ECRIS) and a 1.16 m long LEBT. Within the 1.16 m LEBT, 2 solenoids, 2 steering magnets, a kicker, a space charge compensation section, a collimator, two vacuum valves, a Faraday cup and an ACCT are installed. The manufacture has been completed and the commissioning is on the way. In this paper we will address the commissioning results and its progress.
* Haitao Ren, et al., A Helium Injector for Coupled RFQ and SFRFQ Cavity Project at Peking University. Proc. LINAC’12, Paper TUPB034, Israel, 2012

MOPFI036

Study of the Cold Cathode RF Electron Gun Based on Doped Diamond Films at CAEP

gun, cathode, electron, FEL

366

X. Li
TUB, Beijing, People's Republic of China
W. Bai, M. Li
CAEP/IAE, Mianyang, Sichuan, People's Republic of China

Diamond relevant materials have been considered as a promising field emission cathode in recent years. High current density can be obtained either by diamond field emission arrays or by doped diamond films under electrical strengths of several decades of MV/m. Based on the doped films a half cell S-band electron gun has been designed and constructed at CAEP. The gun can provide an accelerating gradient of 60-80 MV/m on the cathode surface (6 mm in diameter). Simulations have proven good performance of such a gun but it needs confirmed by further experiments. Details of the experiments and comparisons with simulations will be reported.

MOPFI037

Design and Experiment of a Compact C-band Photocathode RF Gun for UED

gun, solenoid, cathode, electron

369

X.H. Liu, H.B. Chen, W.-H. Huang, C.-X. Tang, Z. Zhang
TUB, Beijing, People's Republic of China

A compact C-band photocathode RF gun for the MeV UED facility is developed in Tsinghua University, which is designed to work at the frequency of 5.712GHz. This paper presents the physics and RF structure design, and beam dynamics optimization of this C-band RF gun. Some new structure design will be adopted in this gun, including the optimized cavity length and elliptical iris, which is helpful to achieve lower emittance and larger mode separation. This paper likewise presents experiment parameters and the cold test results of this C-band RF gun.

MOPFI038

Generation and Measurement of Sub-picosecond Electron Bunch in Photocathode RF Gun

laser, electron, radiation, acceleration

372

W.W. Li, Z.G. He, R. Huang, Q.K. Jia, G. Zhou
USTC/NSRL, Hefei, Anhui, People's Republic of China

The generation of subpicosecond electron bunch in the photocathode rf gun was considered and simulated by improving the acceleration gradient of the gun, suitably tuning the charge of the electron bunch and the acceleration phase. To measure the length of the electron bunch, the design of a nondestructive bunch length measurement technology was also presented in this paper.

MOPFI039

The Design of a Compact THz Source Based on Photocathode RF Gun

electron, radiation, gun, space-charge

375

W.W. Li, Z.G. He, R. Huang, Q.K. Jia
USTC/NSRL, Hefei, Anhui, People's Republic of China

Narrow-band THz coherent Cherenkov radiation can be driven by a subpicosecond electron bunch traveling along the axis of a hollow cylindrical dielectric-lined waveguide. We present a scheme of compact THz radiation source based on the photocathode rf gun. On the basis of our analytic result, the subpicosecond electron bunch with high charge (800pC) can be generated directly in the photocathode rf gun. A narrow emission spectrum peaked at 0.24 THz with 2 megawatt (MW) peak power is expected to gain in the proposed scheme (the length of the facility is about 1.2 m), according to the analytical and simulated results.

MOPFI054

Upgrades for the CERN PSB-TO-PS Transfer at 2 GeV

injection, optics, kicker, quadrupole

404

W. Bartmann, J. Borburgh, J.R.T. Cole, S.S. Gilardoni, B. Goddard, O. Hans, M. Hourican, L. Sermeus, R. Steerenberg
CERN, Geneva, Switzerland
C.H. Yu
IHEP, Beijing, People's Republic of China

The CERN PS Booster extraction energy will be upgraded from 1.4 to 2.0 GeV to alleviate the direct space charge tune shift in the PS. The focussing structure of the transfer line will be modified in order to better match the optics between the PSB and the PS. The optics of the PS at injection and, with it, of the transfer line can be adapted to reduce the continuous losses from the already injected and circulating beam bumped towards the septum. Experimental results of the optics optimisation and probing the injection kicker gap will be shown.

MOPFI059

Design and Performance of the Beam Transfer Lines for the HIE-ISOLDE Project

target, simulation, optics, dipole

416

A.S. Parfenova, W. Andreazza, J. Bauche, E.D. Cantero, P. Farantatos, M.A. Fraser, B. Goddard, Y. Kadi, A.J. Kolehmainen, D. Lanaia, M. Martino, R. Mompo, E. Siesling, A.G. Sosa, M.A. Timmins, G. Vandoni, D. Voulot, E.S. Zografos
CERN, Geneva, Switzerland

Beam design and beam optics studies for the HIE-ISOLDE transfer lines have been carried out in MadX, and benchmarked against Trace3D results. Magnet field errors and alignment imperfections leading to deviations from design parameters have been treated explicitly, and the sensitivity of the machine's lattice to different individual error sources was studied. As a result, the tolerances for the various error-contributions have been specified for the different equipment systems. The design choices for the expected magnet field and power supply quality, alignment tolerances, instrument resolution and physical aperture were validated. The methodology and results of the studies are presented.

MOPFI062

Optimization Studies for the SwissFEL RF-Gun

gun, cathode, laser, solenoid

425

M. Schaer, A. Adelmann, A. Anghel, S. Bettoni, P. Craievich, L. Stingelin, C. Vicario, R. Zennaro
PSI, Villigen PSI, Switzerland
Z. Zhang
TUB, Beijing, People's Republic of China

The 250 MeV SwissFEL injector test facility is in operation since August 2010. Measurements with the "CTF2 Gun 5" photocathode S-band rf-gun show promising beam parameters and satisfy the requirements of the SwissFEL project. Since the performance of the electron source is fundamental for the stability and brightness of a free electron laser, further gun optimization studies are pursued. Under investigation is currently a 3.6 cell C-band gun. First ASTRA simulations indicate that with this gun the peak-current can be increased, thanks to a shorter laser pulse and a higher initial acceleration, by almost a factor of two, at slightly better emittance values than the S-band "PSI Gun 1". Since the beam-quality depends also on the achieved performance of the cathode, several copper cathodes had been tested in the SwissFEL injector test facility to analyze the observed rapid degradation of quantum efficiency.

MOPFI074

Ultracold and High Brightness Electron Source for Next Generation Particle Accelerators

electron, laser, plasma, brightness

452

G.X. Xia, R. Appleby, W. Bertsche, M.A. Harvey
UMAN, Manchester, United Kingdom
S. Chattopadhyay
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
S. Chattopadhyay
Cockcroft Institute, Warrington, Cheshire, United Kingdom
A.J. Murray
The University of Manchester, The Photon Science Institute, Manchester, United Kingdom

The ultra-cold plasma-based electron source has recently been proposed as an alternative to the conventional photoemitters or thermionic electron guns, which are widely used in today’s particle accelerators. The advantages of the ultra-cold plasma-based electron source lie in the fact that the electron beam extracted from the cold plasma (from ionization of cold atoms) has very low electron temperature, e.g. down to 10 K, and has the potential for producing high brightness and ultra-short electron bunches. All these features are crucial for the next generation particle accelerators, e.g. free electron lasers, plasma-based accelerators and the future linear colliders. In this paper, we will introduce our proposed facility on cold electron source based at Photon Science Institute (PSI) in the University of Manchester.

MOPFI081

Correlating Structure and Function - In situ X-ray Analysis of High QE Alkali-antimonide Photocathodes

cathode, scattering, controls, vacuum

464

J. Smedley, K. Attenkofer, S.G. Schubert
BNL, Upton, Long Island, New York, USA
I. Ben-Zvi, X. Liang, E.M. Muller, M. Ruiz-Osés
Stony Brook University, Stony Brook, USA
T. Forrest, H.A. Padmore, T. Vecchione, J.J. Wong
LBNL, Berkeley, California, USA
J. Xie
ANL, Argonne, USA

Funding: The authors wish to acknowledge the support of the US DOE, under Contract No. KC0407-ALSJNT-I0013, DE-AC02-98CH10886 and DE-SC0005713. Use of CHESS is supported by NSF award DMR-0936384.
Alkali antimonide photocathodes have high quantum efficiency and low emittance when illuminated by visible light, and are thought to be well suited for use in high-brightness photoinjectors of 4th generation light sources. Here we report on the growth of multi-alkali K2CsSb cathodes on [100] silicon substrates measured using in-situ X-ray diffraction (XRD) and X-ray reflection (XRR). Correlations between cathode structure and growth parameters and the resulting quantum efficiency (QE) are also explored. The best cathodes have a QE at 532 nm in excess of 6% and are structurally textured K2CsSb with grain sizes in excess of 20 nm. In an attempt to reduce the complexity of the current growth methodology we are also making alkali antimonides in parallel via the reaction of bulk materials in an inert environment. This approach has the advantage that the desired stoichiometry can be obtained exactly. Initial diffraction results from prepared bulk materials are promising and show the formation of well reacted K3Sb. In the future we intend to transfer this material to smooth thin photocathode films by either sputtering or pulsed laser deposition.

MOPME020

Development of the New Measurement Method for the Incoherent Tune Spread and the Tune Shift Caused by the Space Charge Effect

dipole, simulation, injection, space-charge

512

S. Kato
Tohoku University, Graduate School of Science, Sendai, Japan
H. Harada, H. Hotchi, M. Kinsho, K. Okabe
JAEA/J-PARC, Tokai-mura, Japan

For the high intensity accelerator, the incoherent tune which is the frequency of the individual particles is shifted and decreases due to the space charge effect. In addition, the incoherent tune is formed into spread shape commonly. When the incoherent tune satisfies a resonance condition, it might be occurred the beam emittance growth and the beam loss. So it is necessary to reduce the incoherent tune spread and the tune shift as much as possible. To achieve this condition, it is desired to measure the incoherent tune spread and the tune shift directly. Therefore we are developing the new measurement method of the incoherent tune spread and the shift due to the space charge effect. From the simulation results, it was cleared that the beam distribution can be modified in the case of using the mono frequency dipole exciter because a particle which has the tune corresponding to the exciter can be resonated temporary. In addition, it was cleared that it is possible to evaluate the incoherent tune spread and the tune shift by the measurement of the distribution transition. We present the outline of this method and the developing plane at the J-PARC RCS.

MOPME022

Beam Commissioning of Two Horizontal Pulse Steering Magnets for Changing Injection Painting Area from MLF to MR in the 3-GeV RCS of J-PARC

injection, stripper, beam-transport, target

518

P.K. Saha, H. Harada, N. Hayashi, H. Hotchi, M. Kinsho, T. Takayanagi, N. Tani
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
Y. Irie
KEK, Ibaraki, Japan
S. Kato
Tohoku University, Graduate School of Science, Sendai, Japan

We have been successfully commissioned two pulse steering magnets installed in the Linac to 3-GeV RCS (Rapid Cycling Synchrotron) injection beam transport (BT) line of J-PARC. RCS has to deliver a simultaneous as well as specific beam as demand by the downstream facilities of MLF (Material and Life Science Facility) and the MR (Main Ring). In order to obtain relatively a smaller transverse emittance at extraction, those magnets were designed to perform a smaller injection painting for the MR beam as compared to the MLF one. As stripper foil position is fixed for the charge exchange H⁻ injection, inclination of the injected beam centroid on foil for the MR beam is only moved to a smaller value by the pulse steering magnets, while DC septum magnets are fixed as determined first for the MLF beam. Their parameters were found to be very consistent with expectation and thus already in operation for switching to a painting area of 100 pi mm mrad for the MR beam as compared to that of 150 pi mm mrad for the MLF beam.

MOPME031

Emittance Measurement with Multi-wire Scanners for BEPC-II Linac

positron, linac, electron, injection

541

H. Geng, W.B. Liu, W. Qiao, Q. Qin, Y.F. Sui, Y. Yue
IHEP, Beijing, People's Republic of China

During the BEPC-II linac upgrade, five wire scanners have been installed in the common transport line, which makes a fast emittance measurement possible. In this paper, we will show the primary results of BEPC-II linac emittance measurement using multi-wire scanner method. The least squares method will be used for data analysis. A comparison of the results with the ones obtained by quad scan method will also be given.

MOPME033

Wire Scanner Emittance Measurement and Software Design at BEPCII

linac, target, quadrupole, EPICS

544

W. Qiao, Z. Duan, H. Geng, W.B. Liu, Y.F. Sui
IHEP, Beijing, People's Republic of China

Wire scanners are diagnostic devices to measure the beam profile. Resent years, BEPCII adopts wire scanner measurement system for accurate beam size and emittance measurements. Beam emittance measurements can be performed with no adverse impact on beam and no interruption to normal machine operation. The BEPCII wire scanner system includes sets of four scanners in linac by which the linac output emittance is determined. In order to make the measurement procedure automated and easily accessible to all operators, wire scanner measurement software is developed. The software can obtain real-time signal data from the Experimental Physics and Industrial Control System(EPICS) and emittance calculation, phase chart and optics envelope display will be done. In this paper we describe the construction, performance and uses of BEPCII wire scanners measurement system and software.

MOPME035

Design of a Non-Intercepting Beam Diagnostic Device Using Neutral Beam Fluorescence Method

neutral-beams, ion, diagnostics, target

547

J. Zhao, J. Chen, J.E. Chen, Z.Y. Guo, S.X. Peng, H.T. Ren, Y. Xu, A.L. Zhang, T. Zhang
PKU, Beijing, People's Republic of China
H.W. Zhao
IMP, Lanzhou, People's Republic of China

The forward neutral beam from deflecting magntic field carries some characteristic properties of high intensity particle beams, such as profile, emittance etc. Therefore a reliable measurement of neutral beam fluorescence can be used to develop a fast and non-interceptive beam diagnostic tool. A non-intercepting beam emittance (profile) monitor using neutral beam fluorescence method has being constructed at Peking University. As a performance test, an emttiance of an extracted proton beam from a permanent magnetic electron cyclotron resonance (ECR) ion source was successfully measured. The details of design and results of measurement will be presented in this paper.

MOPME038

A New Theoretical Design of BLM System for HLS II

electron, vacuum, scattering, monitoring

553

Y.K. Chen, L.J. He, J. Li, W. Li, Y. Li
USTC/NSRL, Hefei, Anhui, People's Republic of China

Beam loss monitoring (BLM) system has been commonly used to detect the vacuum leakage. The existing BLM system for Hefei Light Source (HLS) was built in 2000. It played an important role in analyzing beam loss distribution and regulating the machine operation parameters. Recently, HLS is being upgraded to HLS II. The emittance will be decreased to increase the brilliance of synchrotron radiation. The Touschek lifetime will be much shorter than before, and dominate the total beam lifetime. It is necessary to redesign the BLM system for HLS II. The most important part of this work is to find a better method of monitoring Touschek lifetime by BLM system while keeping its general functions. According to the results of our research, a preliminary theoretical design for the new BLM system is proposed in this paper. This new system will play an important role in the storage ring commissioning, troubleshooting, and beam lifetime studying.

MOPME040

Cavity-based Multi-parameter Beam Diagnostics at HLS

cavity, quadrupole, diagnostics, gun

559

Q. Luo, B.G. Sun
USTC/NSRL, Hefei, Anhui, People's Republic of China

Funding: Natural Science Foundation of China (11005106)
Recent developments of the fourth generation light sources needs precious control of beam parameters, such as beam position, transverse emittance, beam density, bunch length, etc.. Non-destructive on-line beam diagnostic methods are then required. As an example, the cavity beam multi-parameter monitor system designed for the HLS photocathode RF electron gun consists of a beam position monitor, a beam quadrupole moment monitor and a beam density and bunch length monitor. The cavity beam position monitor uses a re-entrant position cavity tuned to TM110 mode as position cavity and cut-through waveguides to suppress the monopole signal. Beam quadrupole moment monitor system consists of a square pill-box quadrupole moment cavity, a cylindrical pill-box reference cavity and a waveguide coupling network. TM0n0 modes of cavity can be used to work out beam density and bunch length simultaneously. To simplify the design and suppress the whole system here, we use the reference cavity of beam position monitor as beam density and bunch length signal pick-up.

MOPME043

Calibration of Beam Position Monitors in the Injector of HLS II

quadrupole, brilliance, coupling, linac

568

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

Funding: Supported by the National Science Foundation of China (11175173, 11105141)
A beam position monitor(BPM) system is being installed to improve the beam position measurement of the injector at the upgrade project of Hefei Light Source (HLS II). The new BPM system is consists of 19 stripline BPMs and 19 Libera Brilliance Single Pass modules. Before installation, the response of the BPMs must be mapped to improve the accuracy of measurement. The theoretical equations of both position and quadrupole component of the BPM are calculated first, using both formula and matlab simulation. A laboratory calibration system is built. The inconsistency of Libera Brilliance Single Pass channels is measured to improve the accuracy of calibration. The calibrating results show the position sensitivity is less than 5% difference compare to the theoretical value, while the quadrupole component sensitivity is less than 10% difference.

MOPME053

Point Spread Function Study of X-ray Pinhole Camera in SSRF

radiation, synchrotron, synchrotron-radiation, storage-ring

592

Z.C. Chen, J. Chen, G.Q. Huang, Y.B. Leng
SSRF, Shanghai, People's Republic of China

Funding: Supported by National Natural Science Foundation of China (11075198)
An X-ray Pinhole Camera that has been used to present the transverse beam size with an intuitive grasp of the distribution of the beam radiation was installed on one beam-line of the storage ring in Shanghai Synchrotron Radiation Facility (SSRF). The real beam size however is a function of the image size of the CCD camera and the point spread function (PSF) of the system. The PSF was calculated but poorly tested. This article will present the measurement of the PSF with a series of beam based experiments and the consistency with the theoretical beam size.

MOPME069

Multi-OTR System for Linear Colliders

target, diagnostics, optics, linac

637

J. Resta-López, A. Faus-Golfe
IFIC, Valencia, Spain
J. Alabau-Gonzalvo, R. Apsimon, A. Latina
CERN, Geneva, Switzerland

We study the feasibility of using a multi-Optical Transition Radiation (mOTR) system for fast transverse emittance reconstruction and x-y coupling correction in the Ring to Main Linac (RTML) of the future linear colliders: ILC and CLIC. OTR monitors are mature and reliable diagnostic tools that could be very suitable for the setup and tuning of the machine in single-bunch mode. Here we study the requirements for a mOTR system adapted to the optical conditions and beam parameters of the RTML of both the ILC and CLIC.

MOPME070

Emittance and Beta Functions Measurements for the MAX IV Linac

quadrupole, simulation, linac, controls

640

N. Čutić, E. Mansten
MAX-lab, Lund, Sweden

We plan to determine beam emittance and Twiss parameters for the MAX IV linac using multiple-quadrupoles scans. We investigate the possibility to perform such scans using matching sections' quadrupoles combined with beam profile measurements by fluorescent YAG screens. Beam pipe size, resolution and screen saturation limits and strengths of quadrupoles are taken into consideration. Our approach to this problem using Kalman filter is presented.

MOPME075

Laser Based Stripping System for Measurement of the Transverse Emittance of H⁻ Beams at the CERN LINAC4

laser, electron, linac, background

652

T. Hofmann, E. Bravin, U. Raich, F. Roncarolo
CERN, Geneva, Switzerland
B. Cheymol
ESS, Lund, Sweden

Funding: LA3NET is funded by the European Commission under Grant Agreement Number GA-ITN-2011-289191
The new LINAC4 at CERN will accelerate H⁻ particles to 160 MeV and allow high brightness proton beam transfers to the Proton Synchrotron Booster, via a charge-exchange injection scheme. This paper describes the conceptual design of a laser system proposed for transverse profile and emittance measurements based on photon detachment of electrons from the H⁻ ions. The binding energy of the outer electron is only 0.75 eV and can easily be stripped with a laser beam. Measuring the electron signal as function of the laser position allows the transverse beam profile to be reconstructed. A downstream dipole can also be used to separate the laser neutralized H⁰ atoms from the main H⁻ beam. By imaging these H⁰ atoms as a function of laser position the transverse emittance can be reconstructed in the same way as in traditional slit-and-grid systems. By properly dimensioning the laser power and spot size, this method results in negligible beam losses and is therefore non-destructive. In addition, the absence of material intercepting the H⁻ beam allows the measurement of a full power H⁻ beam. This paper will focus on the general design and integration of both the laser and H⁰ detector systems.

MOPWA033

Modelling of Parasitic Inductances of a High Precision Inductive Adder for CLIC

impedance, kicker, damping, coupling

738

J. Holma, M.J. Barnes
CERN, Geneva, Switzerland
S.J. Ovaska
Aalto University, School of Science and Technology, Aalto, Finland

The CLIC study is exploring the scheme for an electron-positron collider with high luminosity and a nominal centre-of-mass energy of 3 TeV. The CLIC pre-damping rings and damping rings will produce, through synchrotron radiation, ultra-low emittance beam with high bunch charge. To avoid beam emittance increase, the damping ring kicker systems must provide extremely flat, high-voltage, pulses. The specifications for the extraction kickers of the DRs are particularly demanding: the flat-top of the pulses must be ±12.5 kV with a combined ripple and droop of not more than ±0.02 % (±2.5 V). An inductive adder is a very promising approach to meeting the specifications. However, the output impedance of the inductive adder needs to be well matched to the system impedance. The primary leakage inductance, which cannot be computed accurately analytically, has a significant effect upon the output impedance of the inductive adder. This paper presents predictions, obtained by modelling the 3D geometry of the adder structure and printed circuit boards using the FastHenry code, for primary leakage inductance.

MOPWA034

Electron Tracking Simulations in the Presence of the Beam and External Fields

electron, simulation, proton, space-charge

741

M. Patecki, B. Dehning, G. Iadarola, M. Sapinski
CERN, Geneva, Switzerland

The ionisation profile monitors installed in the CERN LHC and SPS, makes use of the ionisation of small quantities of injected neon gas by the circulating beam. The electrons produced are guided towards the readout system using a combination of electric and magnetic fields. However, in the presence of the beam field their tracks are modified and the resulting profile is distorted. The Geant4 physics simulation package has been used to simulate the ionisation process, while the CERN-developed PyECLOUD code has been used for tracking the resulting ionised particles. In this paper the results of simulations are compared with observations, with conclusions presented on the accuracy of the reconstruction of high-intensity beam profiles.

MOPWA041

The New SLS Beam Size Monitor, First Results

laser, polarization, synchrotron, radiation

759

Á. Saá Hernández, N. Milas, M. Rohrer, V. Schlott, A. Streun
PSI, Villigen PSI, Switzerland
Å. Andersson, J. Breunlin
MAX-lab, Lund, Sweden

Funding: This research has received funding from the European Commission under the FP7-INFRASTRUCTURES-2010-1/INFRA-2010-2.2.11 project TIARA (CNI-PP). Grant agreement no. 261905.
An extremely small vertical beam size of 3.6 μm, corresponding to a vertical emittance of 0.9 pm, only about five times bigger than the quantum limit, has been achieved at the storage ring of the Swiss Light Source (SLS). The measurement was performed by means of a beam size monitor based on the imaging of the vertically polarized synchrotron radiation in the visible and UV spectral ranges. However, the resolution limit of the monitor was reached during the last measurement campaign and prevented further emittance minimization. In the context of the work package “SLS Vertical Emittance Tuning” of the TIARA collaboration, a new improved monitor was built. It provides larger magnification, an increase of resolution and enables two complementary methods of measurement: imaging and interferometry. In this paper we present the design, installation, commissioning, performance studies and first results obtained with the new monitor.

MOPWA049

Status Report of the FETS Photo Detachment Emittance Instrument at RAL

laser, ion, diagnostics, dipole

783

C. Gabor
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
G.E. Boorman, A. Bosco, S.M. Gibson
Royal Holloway, University of London, Surrey, United Kingdom
G.E. Boorman, A. Bosco, S.M. Gibson
JAI, Egham, Surrey, United Kingdom
A.P. Letchford
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
P. Savage
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
V.E. Scarpine
Fermilab, Batavia, USA

The Front End Test Stand at the Rutherford Appleton Laboratory (RAL) is being developed to demonstrate a chopped H⁻ beam of 60 mA at 3 MeV with 10% duty cycle. Due to the high beam power it is advisable to use the technique of photo detachment to avoid intrusive methods. It is intended to apply this technique to perform emittance measurements at the output of the RFQ at full power. This requires a dedicated diagnostics dipole with a special-made vacuum chamber giving room for the different beam paths necessary to install a particle detector to measure the produced neutrals. Other aspects are the beam transport and influence of the dipole and its fringe field to the beam transport Other considerations are the installation of the laser, the optics and the particle detector itself.

MOPWA059

Beam Emittance Measurements and Beam Transport Optimization at the Clatterbridge Cancer Centre

quadrupole, proton, cyclotron, scattering

810

T. Cybulski, O. Karamyshev, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
A. Degiovanni
TERA, Novara, Italy
A. Kacperek, B. Marsland, I. Taylor, A. Wray
The Douglas Cyclotron, The Clatterbridge Cancer Centre NHS Foundation Trust, Wirral, United Kingdom
O. Karamyshev, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

Funding: Cockcroft Institute, Daresbury, Warrington, WA4 4AD, United Kingdom University of Liverpool, Liverpool, United Kingdom
The QUASAR Group is preparing tests of the high energy physics LHCb VELO detector as a non–invasive online dose monitor at the 60 MeV proton therapy beam at the Clatterbridge Cancer Centre (CCC), UK. The proposed method relies on the cross-correlation between the beam halo signal as measured by VELO and the dose delivered to the patient, linked via the absolute intensity of the beam. In order to estimate the expected halo signal and the total beam intensity, studies into proton beam transport through the whole CCC beam line have been carried out. This required the measurement of beam emittance at several positions of the beam delivery system. Quadrupole scans have been realized using a CsI (Tl) scintillating screen in combination with an 8 bit, 13 Mpixel CCD camera. In this contribution, results from measurements are presented and include a discussion of the effects from dispersion in the beam. Experimental data are compared against earlier measurements performed in 1998 and are used as a basis for suggestions targeting an overall optimization of beam transport at CCC.
* Assessing the Suitability of a Medical Cyclotron as an Injector for an Energy Upgrade, J. A. Clarke et all , CLRC Daresbury Laboratory, Warrington, UK

MOPWA061

A New Tool for Longitudinal Tomography in Fermilab's Main Injector and Recycler Rings

booster, controls, injection, space-charge

816

N.J. Evans, S.E. Kopp
The University of Texas at Austin, Austin, Texas, USA
P. Adamson, D.J. Scott
Fermilab, Batavia, USA

Funding: U.S Department of Energy
We are developing software to compute tomographic reconstructions of longitudinal phase space distributions in the Fermi National Accelerator Laboratory Main Injector and Recycler rings using data from existing resistive wall current monitors to diagnose beam quality at injection and provide input distributions for simulation of losses. Building on the algorithm developed by *S. Hancock et al. at CERN the software is able to process a full synchrotron period of a Booster batch of 81 bunches with 18.94 ns spacing and a sampling rate of 2.5 GHz, in < 30 sec, or every ~270 injections. Processing an entire injection opens up the possibility of investigating coupled bunch instabilities via tomography. To speed reconstruction for use on a full injection, phase space maps are created once for a given set of parameters and saved for injections with similar machine settings. We present an overview of the system and studies done on the effect of small errors present including: random noise, mismatch between sampling rate and machine period, errors in locating bunch centers, and trigger jitter.
*Tomographic Measurements of Longitudinal Phase Space Density; 1998 ed. - Hancock, S et al - CERN-PS-98-030-RF

MOPWA073

A Turn-by-turn Beam Profile Monitor using Visible Synchrotron Radiation at CESR-TA

electron, synchrotron, synchrotron-radiation, radiation

849

S. Wang, D. L. Rubin, C.R. Strohman
CLASSE, Ithaca, New York, USA
R.F. Campbell, R. Holtzapple
CalPoly, San Luis Obispo, California, USA

Funding: Work supported by the National Science Foundation and Department of Energy under contract numbers PHY-0734867, PHY-1002467, DMR-0936384, and DE-FC02-08ER41538, DE-SC0006505
A fast beam profile monitor using visible synchrotron radiation (SR) has been constructed and installed in Cornell Electron Storage Ring. This monitor utilizes fast readout electronics based on the Hamamatsu H7260K multi-anode photomultiplier, which has a 32-channel linear array with 1mm channel pitch and sub-nanosecond rise time. In a low emittance lattice at 2 GeV, a double-slit interferometer is employed to measure the horizontal beam size. After careful calibration of the interference pattern, the horizontal beam size within a range of 100 to 500 microns can be measured with a precision of ±5 microns. Due to finite array size, the small vertical beam size is measured by imaging the pi-polarized component of the SR. The fast beam profile monitor is capable of measuring bunch-by-bunch turn-by-turn transverse beam sizes, which eliminates beam jitter inherent when imaging the average beam size with a CCD camera. Details of hardware and software controls are also discussed.

MOPWA076

Improvements to Existing Jefferson Lab Wire Scanners

optics, diagnostics, controls, linac

855

M.D. McCaughan, M.G. Tiefenback, D.L. Turner
JLAB, Newport News, Virginia, USA

This poster will detail the augmentation of selected existing CEBAF wire scanners with commercially available hardware, PMTs, and self created software in order to improve the scanners both in function and utility. Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The U.S. Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for U.S. Government purposes.

MOPWO009

Numerical Studies on the Impact of Ionized Residual Gas on an Electron Beam in an ERL

ion, electron, simulation, linac

903

G. Pöplau, U. van Rienen
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
A. Meseck
HZB, Berlin, Germany

Funding: Supported by BMBF under contract number 05K10HRC
Energy Recovery Linacs (ERLs) are the most promising candidates for next-generation light sources now under active development. An optimal performance of these machines requires the preservation of the high beam brightness generated in the injector. For this, the impact of the ionized residual gas on the beam has to be avoided as it causes instabilities and emittance growth. Typical measures to reduce the effect of ion clouds are clearing electrodes and clearing gaps in the bunch train. In this paper, we present numerical studies of the impact of ion clouds on the electron bunch train. The simulations are performed with the software package MOEVE PIC Tracking developed at Rostock University. ’The model for the bunch and the ion cloud takes into account a distribution of macro particles. The interaction of the bunch with the ion cloud is computed with a 3D space charge model. Hence, particle tracking allows for detailed studies of bunch characteristics such as the emittance. The presented numerical investigations take into account the parameters of the ERL BERLinPro with the objective to deduce appropriate measures for the design and operation of BERLinPro.

MOPWO023

Upgrade and Systematic Measurement Campaign of the ATF2 Multi-OTR System

target, coupling, wakefield, extraction

933

A. Faus-Golfe, J. Alabau-Gonzalvo, C. Blanch Gutierrez, J. Resta-López
IFIC, Valencia, Spain
J. Cruz, E. Marín, D.J. McCormick, G.R. White, M. Woodley
SLAC, Menlo Park, California, USA

A multi-Optical Transition Radiation (mOTR) system made of four stations is being used routinely since September 2011 for transverse beam size measurement and emittance reconstruction in the extraction line of ATF2, providing diagnostic support during the ATF2 tuning operation. Furthermore it is also an excellent tool for fast transverse coupling correction. Due to the compactness of the current design the system has an influence in the increase of the transverse emittance due to wakefield effects when a simultaneous measurement is made. To avoid this effect a new target holder and a new optics has been designed and implemented. In this paper we describe the present status of the ATF2 mOTR system, showing recent performance results, and hardware design improvements.

MOPWO024

Design of the CLIC Pre-Main Linac Collimation System

collimation, linac, wakefield, damping

936

R. Apsimon, A. Latina, D. Schulte, J.A. Uythoven
CERN, Geneva, Switzerland
J. Resta-López
IFIC, Valencia, Spain

A main beam collimation system, upstream of the main linac, is essential to protect the linac from particles in the beam halo. The proposed system consists of an energy collimation (EC) system just after the booster linac near the start of the Ring-to-Main Linac (RTML) transfer line and an EC and betatron collimation (BC) system at the end of the RTML, just before the main linac. The design requirements are presented and the cleaning efficiency of the proposed systems is analysed for different design choices.

MOPWO032

SPS Scraping and LHC Transverse Tails

injection, beam-losses, luminosity, controls

957

L.N. Drøsdal, K. Cornelis, B. Goddard, V. Kain, M. Meddahi, O. Mete, B. Salvachua, G. Valentino, E. Veyrunes
CERN, Geneva, Switzerland

All high-intensity LHC beams have to be scraped before extraction from the SPS to remove the non-Gaussian transverse tails of the particle distributions. The tail particles would otherwise cause unacceptably high losses during injection or other phases of the LHC cycle. Studies have been carried out to quantify the scraping using injection losses and emittance measurements from wire scanners as diagnostics. Beams scraped in the SPS were scraped again in the LHC with collimators to investigate possible tail repopulation. The results of these studies will be presented in this paper.

MOPWO039

Experience with High-intensity Beam Scraping and Tail Populations at the Large Hadon Collider

beam-losses, injection, hadron, diagnostics

978

S. Redaelli, R. Bruce, F. Burkart, D. Mirarchi, B. Salvachua, G. Valentino, D. Wollmann
CERN, Geneva, Switzerland
R.W. Aßmann
DESY, Hamburg, Germany
G. Valentino
University of Malta, Information and Communication Technology, Msida, Malta

The population of beam tails at the LHC is source of concern because even small fractions of the total beam intensity could represent a potential danger is case of slow or fast losses, e.g. caused by orbit transients or by collimator movements. Different studies have been performed using the technique of collimator scans to probe the beam tail population, for different beam energies and beam intensities. The experience accumulated during the operation at 3.5 TeV and 4 TeV is reviewed and extrapolations to higher energies are considered.

MOPWO046

Simulations and Measurements of Beam Losses on LHC Collimators during Beam Abort Failures

simulation, proton, collimation, kicker

996

L. Lari, C. Bracco, R. Bruce, B. Goddard, S. Redaelli, B. Salvachua, G. Valentino
CERN, Geneva, Switzerland
A. Faus-Golfe, L. Lari
IFIC, Valencia, Spain
G. Valentino
University of Malta, Information and Communication Technology, Msida, Malta

Funding: The HiLumi LHC Design Study is included in the HL-LHC project and is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404.
One of the main purposes of tracking simulations for collimation studies is to produce loss maps along the LHC ring, in order to identify the level of local beam losses during nominal and abnormal operation scenarios. The SixTrack program is the standard tracking tool used at CERN to perform these studies. Recently, it was expanded in order to evaluate the proton load on different collimators in case of fast beam failures. Simulations are compared with beam measurements at 4 TeV. Combined failures are assumed which provide worst-case scenarios of the load on tungsten tertiary collimators.

MOPWO057

A Precise Beam Dynamics Model of the PSI Injector 2

space-charge, cyclotron, simulation, injection

1020

A.M. Kolano, R.J. Barlow
University of Huddersfield, Huddersfield, United Kingdom
A. Adelmann, C. Baumgarten
PSI, Villigen PSI, Switzerland

The Injector 2 at PSI (Paul Scherrer Institut), is a 72 MeV separate sector cyclotron producing a high intensity proton beam up to 3 mA CW, which is subsequently injected to the 590 MeV Ring Cyclotron. The injection energy of the pre-bunched beam is 870 keV at an intensity of 10 to 11 mA. In this paper we describe a full 3D model of the PSI injector 2, starting just before the two bunchers and including the multi stage collimation scheme in the cyclotron. The precise beam dynamics model is based on the OPAL (Object Oriented Parallel Accelerator Library) simulation code. OPAL is a tool for charged-particle optic calculations in large accelerator structures and beam lines including 3D space charge. The presented model will be validated with data from radial profile measurements and loss rates from the collimators and the electrostatic septum in the Injector 2. Based on this model we will estimate the intensity limit of this machine and comment of future operation modes.

MOPWO061

Numerical Approaches for Simulation of Stochastic Cooling in 2D Phase Space

simulation, coupling, electromagnetic-fields, storage-ring

1028

M. Dolinska
NASU/INR, Kiev, Ukraine
C. Dimopoulou, A. Dolinskyy, F. Nolden
GSI, Darmstadt, Germany

A consolidated fluid-dynamics algorithm for the analysis of beam dynamics under the influence of the electromagnetic field is presented. Aiming at simulating stochastic cooling of particle beams in 2D space, two numerical algorithms solving the 2D Fokker-Planck Equation are described. As an alternative approach, a numerical method based on the macro-particle tracking turn in turn in the ring (i.e. in the time domain) is introduced. Some results of the simulation of the stochastic cooling in the Collector Ring by both methods are discussed.

MOPWO062

A Parallel Multi-objective Differential Evolution Algorithm for Photoinjector Beam Dynamics Optimization

controls, electron, solenoid, gun

1031

J. Qiang, C.E. Mitchell, S. Paret, R.D. Ryne
LBNL, Berkeley, California, USA
Y.X. Chao
UCB, Berkeley, California, USA

Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231
In photoinjector design, there is growing interest in using multi-objective beam dynamics optimization to minimize the final transverse emittances and to maximize the final peak current of the beam. Most previous studies in this area were based on genetic algorithms. Recent progress in optimization suggests that the differential evolution algorithm could perform better in comparison to the genetic algorithm. In this paper, we propose a new parallel multi-objective optimizer based on the differential evolution algorithm for photoinjector beam dynamics optimization. We will discuss the numerical algorithm and some benchmark examples. This algorithm has the potential to significantly reduce the computation time required to reach the optimal Pareto solution.

MOPWO073

Design and Simulation of an Extraction Section for the University of Maryland Electron Ring

extraction, dipole, simulation, quadrupole

1052

K.J. Ruisard, B.L. Beaudoin, S. Bernal, J.A. Butcher, I. Haber, R.A. Kishek, T.W. Koeth, D.F. Sutter
UMD, College Park, Maryland, USA

Funding: Supported by the US Dept. of Energy, Office of High Energy Physics, and by the US Dept. of Defense, Office of Naval Research and the Joint Technology Office.
The University of Maryland Electron Ring (UMER) is a low-energy scaled facility for the study of intense beam dynamics, relevant to higher energy, high intensity accelerators. Many parameters crucial to understanding space charge dominated beam evolution, such as transverse emittance and longitudinal temperature, require the use of turn-by-turn interceptive diagnostics. To meet this need, we plan to implement an extraction section with a fast-pulsed electric-field kicker. This paper presents a suite of simulations used to guide the design process and predict extraction performance, using the WARP Particle-in-cell (PIC) code. Simulations in a transverse slice geometry predict beam trajectory and monitor beam evolution through extraction. After isolating a design based on centroid tracking, extraction acceptance is probed and an analysis proposed to estimate the error tolerances of the new ring elements.

MOPWO085

A Hybrid Technique for Computing Courant-Snyder Parameters from Beam Profile Data

space-charge, simulation, linac, DTL

1073

C.K. Allen
ORNL, Oak Ridge, Tennessee, USA
E.N. Dai
Washington University in St. Louis, St. Louis, USA

Funding: Work supported by ORNL/SNS, which is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725.
We present a technique for computing the Courant-Snyder parameters of a charged-particle beam from profile measurement data. Such algorithms are not new, but this particular method has very robust convergence properties resulting from a novel approach that combines both deterministic and non-deterministic methods. The general idea is as follows: given a model of the beamline, in the zero-current case it is possible to compute the Courant-Snyder parameters directly from profile data using a deterministic, linear-algebraic approach. For the finite beam current case we can construct a smooth curve of these deterministic solutions starting from the zero-current solution and terminating at the finite-current case. We are guaranteed convergence, and convergence to the finite-current solution connected to the zero-current Courant-Snyder parameters. This approach avoids the convergence issues associated with a fully iterative, non-deterministic method. The details of the technique are outlined and examples are presented using profile data taken from the SNS accelerator.

TUYB101

Progress in Super B-Factories

luminosity, linac, positron, alignment

1096

K. Akai
KEK, Ibaraki, Japan

The upgrade of B-Factories to Super B-Factories, which will search for new physics beyond the Standard Model, opens the way for new luminosity frontier. The status of Super B-Factories will be reported.

Slides TUYB101 [42.300 MB]

TUOCB103

Quasi Traveling Wave Side Couple RF Gun for SuperKEKB

gun, cavity, focusing, cathode

1117

T. Natsui, Y. Ogawa, M. Yoshida, X. Zhou
KEK, Ibaraki, Japan

We are developing a new RF gun for SuperKEKB. High charge low emittance electron and positron beams are required for SuperKEKB. We will generate 7.0 GeV electron beam at 5 nC 20 mm-mrad by J-linac. In this linac, a photo cathode S-band RF gun will be used as the electron beam source. For this reason, we are developing an advanced RF gun. We have tested a Disk and Washer (DAW) type RF gun. Additionally, another new RF gun which has two side coupled standing wave field is developed. We call it quasi traveling wave side couple RF gun. This gun has a strong focusing field at the cathode and the acceleration field distribution also has a focusing effect. The design of RF gun and experimental results will be shown.

Slides TUOCB103 [2.959 MB]

TUODB102

Intrabeam Scattering Studies for Low Emittance of BAPS

wiggler, damping, storage-ring, lattice

1123

S.K. Tian, Y. Jiao, J.Q. Wang, G. Xu
IHEP, Beijing, People's Republic of China

In modern storage ring light sources, intra-beam scattering (IBS) is often thought of as a fundamental limitation to achieving ultra-low emittance and hence higher brightness. Beijing Advanced Photon Source (BAPS) is under design at Institute of High Energy Physics (IHEP) which aims to emittance less than 1nm at 5GeV. To improve the coherence and high brightness, low emittance- in both transverse planes at the diffraction limit for the range of x-ray wavelengths(≈10 pm)- is being pursued. Thus, due to the very low emittance, intra-beam scattering effect is an issue. Accurate estimation to check if the design goal can be reached is necessary. In this paper, we use the 6-D accelerator simulation code-elegant and Accelerator Toolbox (AT)-a collection of tools to model storage rings in the MATLAB environment. Based on a temporary design lattice of BAPS, we present the results of particle simulation study of intra-beam scattering effect versus the beam energy, the emittance coupling factor, the bunch length, the bunch current and so on. We also studied the mitigating method by adopting damping wigglers in one or more dispersion-free regions.

Slides TUODB102 [2.338 MB]

TUODB103

Recent Results from CesrTA Intrabeam Scattering Investigations

coupling, simulation, damping, scattering

1126

M. P. Ehrlichman, A. Chatterjee, W. Hartung, D.P. Peterson, N.T. Rider, D. L. Rubin, D. Sagan, J.P. Shanks, S. Wang
CLASSE, Ithaca, New York, USA

Funding: This research was supported by NSF and DOE contracts PHY-0734867, PHY-1002467, PHYS-1068662, DE-FC02-08ER41538, DE-SC0006505.
Manifestation of intrabeam scattering (IBS) in an electron/positron storage ring depends on the radiation damping time in two ways. First, the beam size is the equilibrium of the IBS growth rate in each of the three degrees of freedom and corresponding damping rates. Second, scattering events that occur less frequently than order once per damping time contribute to non-Gaussian tails that are invisible to our beam size monitors. The tail cut procedure excludes these relatively rare events in the calculation of equilibrium beam size. In machines with short damping times, the tail cut significantly reduces the effective IBS growth rate. At CesrTA, we measure the dependence of beam size on bunch charge in IBS-dominated beams. We vary the vertical emittance using a closed optics bump that increases the vertical dispersion and transverse coupling in the wiggler regions. Measurements are taken at both 2.1 and 2.3 GeV. Here we report the results of these experiments and compare those results to theory.

Slides TUODB103 [1.221 MB]

TUOAB201

Ultra-Short X-ray Pulse Generation by Electron Beam Slicing in Storage Rings

electron, storage-ring, linac, photon

1134

L.-H. Yu, F.J. Willeke
BNL, Upton, Long Island, New York, USA

Funding: Department of Energy, USA
We propose a new method to generate ultra-short x-ray pulses using focused short low energy (5-10MeV) electron bunch to slice a short electron bunch from the electron bunches in a synchrotron radiation storage ring. When the low energy electron bunch crosses from top the high energy electron bunch at right angle, its coulomb force will kick a short slice of high energy electrons away from the core of the storage ring electron bunch. When the low energy electron bunch (about 50 pC) is focused to about 50 micron size and compressed to about 150fs bunch length and is positioned on top of the high energy electron bunch by a distance about 30 micron, the coulomb force is sufficient to give a kick vertically to the electrons within a short slice of the storage ring bunch about 200 fs long with a deflection about 4 micro-radian. This is sufficient to deflect the slice away from the core by a separation of 5 times the angular divergence of the beam. The separated slice when passing through an undulator, will radiate ulstra-short x-ray pulses at about 200 fs. We discuss the advantages and challenges of this new method. We provide data to demonstrate the feasibility of this method.

Slides TUOAB201 [1.578 MB]

TUOAB203

ESRF Upgrade Phase II

lattice, storage-ring, vacuum, brilliance

1140

J.-L. Revol, P. Berkvens, J.C. Biasci, J-F. B. Bouteille, N. Carmignani, F. Ewald, L. Farvacque, A. Franchi, L. Goirand, M. Hahn, L. Hardy, J. Jacob, J.M. Koch, G. Lebec, S.M. Liuzzo, B. Nash, T.P. Perron, E. Plouviez, P. Raimondi, K.B. Scheidt, V. Serrière
ESRF, Grenoble, France

Four years after the launch of the Upgrade Programme, the ESRF is midway through its first phase (2009-2015) and has defined the objectives for the ensuing second phase. The first phase paved the way to a new generation of nano-beam X-ray beamlines fed by an X-ray source itself substantially improved in terms of reliability, stability and brilliance. The second phase envisions a major upgrade of the source to best serve the science case of this new generation of beamlines. In December 2012, the ESRF Council endorsed Management's proposal to launch the technical design study of a new 7-bend achromat lattice. This new configuration will allow the ESRF storage ring to operate with a decrease in horizontal emittance by a factor of about 30 and a consequent increase in brilliance and coherence of the photon beam. The increase will be substantially higher at X-ray energies larger than 50 keV.

Slides TUOAB203 [3.664 MB]

TUPEA007

Spontaneous Radiation Calculations for the European XFEL

undulator, radiation, electron, FEL

1176

I.V. Agapov, G. Geloni
XFEL. EU, Hamburg, Germany
O.V. Chubar
BNL, Upton, Long Island, New York, USA
M. Scheer, M. Titze
HZB, Berlin, Germany
N.V. Smolyakov, S.I. Tomin
NRC, Moscow, Russia

Calculating spontaneous radiation emission from long undulators such as those present in the European XFEL, being background to FEL radiation, is still important for several diagnostics and science cases. For realistic setups, and including effects of electron beam focusing, emittance and energy spread in the electron beam, these calculations should be performed numerically. We present these calculations for several electron beam and undulator parameters performed by various codes. Sensitivity of different spontaneous radiation characteristics, in various collection schemes, to the electron beam and undulator magnetic field parameters is studied

TUPEA017

Monoenergetic Electron Beams with Ultralow Normalized Emittance Generated from Laser-Gas Interaction

laser, electron, plasma, simulation

1196

D.Z. Li, J. Gao, K. Huang, J. Jiarui, Y. Ma
IHEP, Beijing, People's Republic of China
L.M. Chen, W.C. Yan
Institute of Physics, Chinese Academy of Sciences, Beijing, People's Republic of China

High quality electron bunches are generated by using 2 TW, 80 fs, high contrast laser pulses interacting with helium gas targets. In optimized condition, we get tens MeV monoenergetic electron beams with small energy spread and the normalized emittance 0.07π mm·mrad. Due to its ultra small emittance and high initial energy, such bunch is very suitable for high current linear accelerators.

TUPEA042

Linac Design for Dalian Coherent Light Source

linac, FEL, simulation, laser

1226

M. Zhang, H.X. Deng, D. Gu, Q. Gu
SINAP, Shanghai, People's Republic of China

Dalian Coherent Light (DCL) Source is a FEL user facility in which HGHG scheme is adopted. Beam quality requirements for the linear accelerator (linac) are critical, including not only the beam brightness, but also the stability and the reliability. In this paper, optimization study is performed for the linac. Based on beam stability simulation in the longitudinal direction, the tolerant budget is formed for the short period jitter. For the transverse orbit error, beam based alignment (BBA) technique is implemented by beam dynamics simulations and the transverse jitter is also presented accordingly. Measurement method for the beam quality is also described in the paper.

TUPEA050

Extension of the MAX IV Linac for a Free Electron Laser in the X-ray Region

linac, FEL, undulator, electron

1244

F. Curbis, N. Čutić, M. Eriksson, O. Karlberg, F. Lindau, A. Mak, E. Mansten, S. Thorin, S. Werin
MAX-lab, Lund, Sweden

The 3 GeV linac for the MAX IV laboratory is currently under construction in Lund (Sweden). As full energy injector for the MAX IV rings, a thermionic gun will be used to create electrons. However a photocathode gun planned for a short pulse facility (SPF) will deliver small emittance and ultra-short electron bunches that will be suitable to also drive a Free-Electron Laser. Moreover extending the linac energy with 1 or 2 GeV will give the opportunity to get closer to 1 Angstrom radiation with much more flexibility and better performances. Given these opportunities at the MAX IV laboratory, a free electron laser is envisaged in the long term perspective of the facility. In this study we investigate the case of a 5 GeV machine which can produce radiation in the X-ray region. The FEL design will benefit from the implementation of self-seeding, to enhance stability of the central wavelength and spectral bandwidth. Tapering along variable gap undulators will help to extract the maximum photon flux and increase the brilliance of the source. Among others, this kind of machine would be suitable for time resolved experiments and imaging.

TUPEA052

Design Study for a CERN Short Base-Line Neutrino Facility

target, proton, extraction, secondary-beams

1250

R. Steerenberg, M. Calviani, I. Efthymiopoulos, A. Ferrari, B. Goddard, R. Losito, M. Nessi, J.A. Osborne, L. Scibile, H. Vincke
CERN, Geneva, Switzerland
P.R. Sala
Istituto Nazionale di Fisica Nucleare, Milano, Italy

A design study has been initiated at CERN for the conception and construction of a short base line neutrino facility, using a proton beam from the CERN Super Proton Synchrotron (SPS) that will be transferred to a new secondary beam production facility, which will provide a neutrino beam for experiments and detector R&D. This paper resumes the general layout of the facility together with the main primary and secondary beam parameters and the choices favoured for the neutrino beam production.

TUPEA059

CLARA Accelerator Design and Simulations

linac, diagnostics, FEL, laser

1268

P.H. Williams, D. Angal-Kalinin, J.K. Jones, B.P.M. Liggins, J.W. McKenzie, B.L. Militsyn
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
D. Angal-Kalinin, J.K. Jones, B.P.M. Liggins, J.W. McKenzie, P.H. Williams
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: Science & Technology Facilities Council
We present the accelerator design for CLARA (Compact Linear Advanced Research Accelerator) at Daresbury Laboratory. CLARA will be a testbed for novel FEL configurations. The accelerator will consist of an RF photoinjector, S-band acceleration and transport to 250 MeV including X-band linearisation and magnetic bunch compression. We describe the transport in detail including dedicated diagnostic sections. Beam dynamics simulations are then used to define a set of operating working points suitable for the different FEL schemes intended to be tested on CLARA.

TUPEA071

THz Bench Tests of a Slab-symmetric Dielectric Waveguide

acceleration, laser, simulation, wakefield

1292

F. Lemery, H. Panuganti, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
D. Mihalcea, P. Piot
Fermilab, Batavia, USA
P. Stoltz
Tech-X, Boulder, Colorado, USA

Funding: This work is supported by DTRA contract HDTRA1-10-1-0051 and by the U.S. DOE contracts DE-FG02-08ER41532 and DE-AC02-07CH11359.
Dielectric-lined waveguides (DLW) are becoming more popular for beam driven acceleration applications. An experiment to demonstrate beam-driven acceleration using a slab-symmetric dielectric-lined waveguide driven by a flat beam is in preparation at the Advanced Superconducting Test Accelerator (ASTA) at Fermilab. In this paper we characterize the structure using a THz pulse obtained from optical rectification using an amplified laser pulse. After propagation through the DLW structure, the THz pulse is analyzed using a Michelson interferometer and single-shot electro-optical imaging. Data for various gap size will be presented.

TUPEA072

Toward a Dielectric-Wakefield Energy Doubler at the Fermilab's Advanced Superconducting Test Accelerator

acceleration, electron, simulation, wakefield

1295

F. Lemery, D. Mihalcea, P. Piot, C.R. Prokop
Northern Illinois University, DeKalb, Illinois, USA
P. Piot, Y.-E. Sun
Fermilab, Batavia, USA
P. Stoltz
Tech-X, Boulder, Colorado, USA

Funding: This work is supported by DTRA contract HDTRA1-10-1-0051 and by the U.S. DOE contracts DE-FG02-08ER41532 and DE-AC02-07CH11359.
The Advanced Superconducting Test Accelerator (ASTA), presently under construction at Fermilab, will produce high-charge (~<3 nC) electron bunches with energies ranging from 50 to eventually 750 MeV. The facility is based on a superconducting linac capable of producing up to 3000 bunches in 1-ms macropulses repeated at 5 Hz. In this paper we explore the use of a short dielectric-lined-waveguide (DLW) linac to significantly increase the bunch energy. The method consists in (1) using advanced phase space manipulation techniques to shape the beam distribution and enhance the transformer ratio, and (2) optimize the generation and acceleration of a low-charge witness bunches. Start-to-end simulations of the proposed concept are presented. This DLW module could also be used to test some aspects of a recently proposed concept for a multiuser short-wavelength free-electron laser utilizing a series of DLW linacs*.
* C. Jing et al., “A Compact Soft X-ray Free-Electron Laser Facility based on a Dielectric Wakefield Accelerator”, Advanced Photon Source LS Note LS-332, Argonne National Laboratory (2012).

TUPEA086

Femtosecond Electron Beam and X-ray Beams at the Linac Coherent Light Source

FEL, linac, electron, laser

1316

Y.T. Ding, A. Brachmann, F.-J. Decker, R.C. Field, J.C. Frisch, Z. Huang, R.H. Iverson, H. Loos, H.-D. Nuhn, D.F. Ratner, J.L. Turner, J.J. Welch, J. Wu, F. Zhou
SLAC, Menlo Park, California, USA
P. Emma
LBNL, Berkeley, California, USA

Generation of ultrashort x-ray pulses (femtoseconds to attoseconds) is attracting much attention within the x-ray FEL user community. At the Linac Coherent Light Source (LCLS), we have successfully delivered femtosecond x-ray pulses to the users with two operating modes – low-charge (20-40pC) scheme and emittance spoiling foil method. Diagnostics on the femtosecond beams is also a challenging topic and good progresses have been made at LCLS. In this paper we report the experimental studies on the two femtosecond operation schemes, the x-ray performance and also the diagnostic progress.

TUPFI002

Electron Cloud and Scrubbing Studies for the LHC

injection, electron, dipole, luminosity

1331

G. Iadarola
Naples University Federico II, Science and Technology Pole, Napoli, Italy
G. Arduini, V. Baglin, H. Bartosik, C.O. Domínguez, J. Esteban Müller, G. Iadarola, G. Rumolo, E.N. Shaposhnikova, L.J. Tavian, F. Zimmermann
CERN, Geneva, Switzerland
C.O. Domínguez
EPFL, Lausanne, Switzerland
G.H.I. Maury Cuna
CINVESTAV, Mexico City, Mexico

Electron cloud build-up resulting from beam-induced multipacting is one of the major limitations for the operation of the LHC with beams with close bunch spacing. Electron clouds induce unwanted pressure rise, heat loads on the beam screens of the superconducting magnets and beam instabilities. Operation with bunch spacing of 50 ns in 2011 and 2012 has required decreasing the Secondary Electron Yield of the beam screens below the multipacting threshold for beams with this bunch spacing. This was achieved by continuous electron bombardment induced by operating the machine with high intensity beams with 50 and 25 ns spacing during dedicated periods at injection energy (450 GeV) and at top energy (3.5 and 4 TeV). The evolution of the Secondary Electron Yield during these periods, at different sections of the machine, can be estimated by pressure, heat load and by bunch-by-bunch RF stable phase measurements. The experimental information on the scrubbing process will be discussed and a possible “scrubbing strategy” to allow the operation with 50ns and 25ns beams after the Long Shutdown in 2013-2014 will be presented.

TUPFI004

Longitudinal Manipulation to Obtain and Keep the Low Emittance and High Charge Electron Beam for SuperKEKB Injector

wakefield, laser, alignment, gun

1337

M. Yoshida, N. Iida, T. Natsui, Y. Ogawa, S. Ohsawa, H. Sugimoto, L. Zang, X. Zhou
KEK, Ibaraki, Japan

The design strategy of SuperKEKB is based on the.nano-beam scheme. The dynamic aperture decreases due to the very small beta function at the interaction point. Thus the injector upgrade is required to obtain the low emittance and high charge beam corresponding to the short beam life and small injection acceptance. The required beam parameters are 5 nC, 20 mm mrad and 4 nC, 6 mm mrad for the electron and positron respectively. For the electron beam, we installed new photocathode RF-Gun with the focusing electric field and temporal adjusting laser system. Further the projected emittance dilution in the LINAC is an important issue for the low emittance injection. The longitudinal bunch length and shape is an important key to avoid the space charge effect and emittance dilution. The longitudinal manipulation using the temporal adjusting laser system and the bunch compression will be presented. Further the longitudinal bunch measurement will be also presented.

TUPFI020

Towards a Symmetric Momentum Distribution in the Muon Ionization Cooling Experiment

simulation, solenoid, quadrupole, collider

1376

O.M. Hansen
University of Oslo, Oslo, Norway
A.P. Blondel
DPNC, Genève, Switzerland
I. Efthymiopoulos, O.M. Hansen
CERN, Geneva, Switzerland

The Muon Ionization Cooling Experiment (MICE) is under development at Rutherford Appleton Laboratory (UK). It's a proof-of-principle experiment for ionization cooling, which is a prerequisite for a future Neutrino Factory(NF) or a Muon Collider. The muon beam is designed to have a symmetrical momentum distribution in the cooling channel of the NF. In the MICE beamline pions are captured by a quadrupole triplet, then pion momentum is selected by dipole 1 (D1) after which the pions decay to muons in the decay solenoid. After the decay solenoid, the muon beam momentum is selected by dipole 2 (D2), the beam is focused in two quadrupole triplets and is finally characterized by a set of detectors. By doing a D1-scan of the currents, where the optics parameters are scaled according to the pion momentum, from 238-450 MeV/c the muon momentum distribution is changed. In this paper simulation results from G4Beamline and real data from MICE are presented and compared.

TUPFI024

Influence of the Ats Optics on Intra-Beam Scattering for HL-LHC

optics, luminosity, simulation, collider

1388

M. Schaumann, R. Bruce, J.M. Jowett
CERN, Geneva, Switzerland
M. Schaumann
RWTH, Aachen, Germany

In the future High Luminosity (HL-)LHC the influence of intra-beam scattering (IBS) will be stronger than in the present LHC, because of higher bunch intensity, small emittance and new optics. The new ATS-optics scheme modifies the lattice in the arcs around the main interaction points (IP) to provide β* values as small as 0.15m in the IP, however those modifications affect the IBS growth rates. In this paper proton IBS emittance growth rates are calculated with MADX and the Collider Time Evolution (CTE) program for two ATS-optics versions, different settings of the crossing angles and required corrections and various beam conditions at injection (450 GeV) and collision (7 TeV) energy. CTE simulations of the expected luminosity, intensity, emittance and bunch length evolution during fills are also presented

TUPFI025

Bunch-by-Bunch Analysis of the LHC Heavy-Ion Luminosity

luminosity, injection, simulation, ion

1391

M. Schaumann, J.M. Jowett
CERN, Geneva, Switzerland

After the first run in 2010, the LHC continued its heavy-ion operation with collisions of lead nuclei in late 2011. The beam dynamics of those high intensity lead beams are strongly influenced by intra-beam scattering (IBS), especially on the injection plateau. Each batch injected from the SPS spends a different time at injection, introducing significant changes from batch to batch. Within the batches there is an even larger spread imprinted by the SPS injection plateau. This results in a spread of the luminosity produced in each bunch crossing. The particle losses during collisions are dominated by nuclear electromagnetic processes, leading to a non-exponential intensity decay during the fill and short luminosity lifetime at 3.5 Z TeV. The luminosity, emittance, intensity and bunch length evolution of the 2011 run was analysed bunch-by-bunch and compared with simulations. Based on this analysis, estimates of the potential luminosity performance at 6.5 Z TeV, after the present shutdown, are given.

TUPFI026

Investigations of the LHC Emittance Blow-Up during the 2012 Proton Run

injection, luminosity, proton, target

1394

M. Kuhn
Uni HH, Hamburg, Germany
G. Arduini, P. Baudrenghien, J. Emery, A. Guerrero, W. Höfle, V. Kain, M. Lamont, T. Mastoridis, F. Roncarolo, M. Sapinski, M. Schaumann, R.J. Steinhagen, G. Trad, D. Valuch
CERN, Geneva, Switzerland

About 30 % of the potential luminosity performance is lost through the different phases of the LHC cycle, mainly due to transverse emittance blow-up. Measuring the emittance growth is a difficult task with high intensity beams and changing energies. Improvements of the LHC transverse profile instrumentation helped to study various effects. A breakdown of the growth through the different phases of the LHC cycle is given as well as a comparison with the data from the LHC experiments for transverse beam size. In 2012 a number of possible sources and remedies have been studied. Among these are intra beam scattering, 50 Hz noise and the effect of the transverse damper gain. The results of the investigations are summarized in this paper. Requirements for transverse profile instrumentation for post LHC long shutdown operation to finally tackle the emittance growth are given as well.

TUPFI028

Beam Losses Through the LHC Operational Cycle in 2012

proton, beam-losses, luminosity, injection

1400

G. Papotti, A.A. Gorzawski, M. Hostettler, R. Schmidt
CERN, Geneva, Switzerland

We review the losses through the nominal LHC cycle for physics operation in 2012. The loss patterns are studied and categorized according to timescale, distribution, time in the cycle, which bunches are affected, whether coherent or incoherent. Possible causes and correlations are identified, e.g. to machine parameters or instability signatures. A comparison with losses in the previous years of operation is also shown.

TUPFI029

Luminosity Lifetime at the LHC in 2012 Proton Physics Operation

luminosity, target, proton, optics

1403

M. Hostettler, G. Papotti
CERN, Geneva, Switzerland

In 2012, the LHC was operated at 4 TeV flat top energy with beam parameters that allowed exceeding a peak instantaneous luminosity of 7500 (ub*s)^-1 and a total of 23 fb^-1 integrated luminosity in the ATLAS and CMS experiments. This paper elaborates on the evolution of the LHC luminosity and luminosity lifetime during proton physics fills and through the year 2012. Bunch to bunch differences and the impact of different machine settings are highlighted.

TUPFI037

Collimation Down to 2 Sigma in Special Physics Runs in the LHC

proton, scattering, background, luminosity

1427

H. Burkhardt, S. Jakobsen, S. Redaelli, B. Salvachua, G. Valentino
CERN, Geneva, Switzerland

We report on observations with collimation very close to the beam. Primary collimators were moved in small steps down to 2 σ from the beam axis to allow for measurements of very forward proton scattering in special high-beta runs in the LHC. We studied the reduction in intensity as a function of collimator position which provides information about the halo shape. After scraping at 2 σ, collimators were retracted to 2.5 σ. This allowed for measurements of very forward proton-proton scattering with roman pot detectors at 3 σ from the beam axis at acceptable background levels for about an hour. Good background conditions were restored by another scraping with primary collimators at 2 σ. Beam lifetimes and halo repopulation times were found to be sufficiently long to allow for several hours of data taking between scraping in a single LHC fill.

TUPFI042

Beam Parameters and Luminosity Time Evolution for an 80-km VHE-LHC

luminosity, radiation, damping, collider

1442

C.O. Domínguez, F. Zimmermann
CERN, Geneva, Switzerland

The Very High Energy LHC (VHE-LHC) is a recently proposed proton-proton collider in a new 80-km tunnel. With a dipole field of 15-20 T it would provide a collision energy of 76-100 TeV c.m. We discuss the VHE-LHC beam parameters and compute the time evolution of luminosity, beam current, emittances, bunch length, and beam-beam tune shift during a physics store. The results for VHE-LHC are compared with those for HE-LHC, a 33-TeV (20-T field) collider located in the existing LHC tunnel.

TUPFI046

The MICE Experiment

solenoid, target, simulation, quadrupole

1454

A.P. Blondel
DPNC, Genève, Switzerland

Ionization Cooling is the only practical solution to preparing high brilliance muon beams for a neutrino factory or muon collider. MICE is under development at the Rutherford Appleton Laboratory (UK). It is characterized by exquisite emittance determination by 6D measurement of individual particles, a cooling section comprising 23 MV of acceleration at 200 MHz and 3 liquid hydrogen absorbers totaling 1m of liquid hydrogen on the path of 140-240 MeV/c muons. The beam has already been commissioned successfully and first measurements of beam emittance performed. We are setting up for the final high precision emittance determination and the measurements of cooling in Li Hydrogen. The design offers opportunities to observe cooling with various absorbers and several optics configurations. Results will be compared with detailed simulations of cooling channel performance to ensure full understanding of the cooling process. Progress towards the full cooling experiment with RF re-acceleration will also be reported.
Submitted by the MICE speakers bureau
hoping for a contributed oral
to be give by the spokesperson, prof. A. Blondel

TUPFI054

MICE Spectrometer Solenoid Magnetic Field Measurements

solenoid, simulation, shielding, factory

1466

M.A. Leonova
Fermilab, Batavia, USA

The Muon Ionisation Cooling Experiment (MICE) is designed to demonstrate ionization cooling in a muon beam. Its goal is to measure a 10% change in transverse emittance of a muon beam going through a prototype Neutrino Factory cooling channel section with a 1% accuracy, corresponding to an absolute measurement accuracy of 0.1%. To measure the emittance, MICE uses two solenoidal spectrometers. The Spectrometer Solenoids are designed to have 4 T solenoidal fields, uniform at 3 per mil level in the tracking volumes. Analysis of magnetic field measurements of the Spectrometer Solenoids will be discussed, and results of extracting precise coil positions, angles, and coil radius measurements for input into magnet models will be presented.

TUPFI056

A Muon Collider as a Higgs Factory

collider, luminosity, factory, target

1472

D.V. Neuffer, Y.I. Alexahin, M.A. Palmer
Fermilab, Batavia, USA
C.M. Ankenbrandt
Muons. Inc., USA
J.-P. Delahaye
SLAC, Menlo Park, California, USA

Because muons connect directly to a standard-model Higgs particle in s-channel production, a muon collider would be an ideal device for precision measurement of the mass and width of a Higgs-like particle, and for further exploration of its production and decay properties. The LHC has seen evidence for a 126 GeV Higgs particle, and a muon collider at that energy could be constructed. Parameters of a high-precision muon collider are presented and the necessary components and performance are described. An important advantage of the muon collider approach is that the spin precession of the muons will enable energy measurements at extremely high accuracy (E/E to 10^-6 or better). Extension to a higher-energy higher-luminosity device is also discussed.

TUPFI060

Complete Muon Cooling Channel Design and Simulations

beam-cooling, dipole, factory, simulation

1484

C. Y. Yoshikawa, C.M. Ankenbrandt, R.P. Johnson
Muons. Inc., USA
Y.S. Derbenev, V.S. Morozov
JLAB, Newport News, Virginia, USA
D.V. Neuffer, K. Yonehara
Fermilab, Batavia, USA

Considerable progress has been made in developing promising subsystems for muon beam cooling channels to provide the extraordinary reduction of emittance required for an Energy-Frontier Muon Collider, but lacks an end-to-end design. Meanwhile, the recent discovery of a Higgs-like boson has created interest in the High Energy physics community for a Higgs Factory to investigate its properties and verify whether it is Standard Model or beyond. We present principles and tools to match emittances between and within muon beam cooling subsystems that may have different characteristics. The Helical Cooling Channel (HCC), which combines helical dipoles and a solenoid field, allows a general analytic approach to guide designs of transitions from one set of cooling channel parameters to another. These principles and tools will be applied to design a complete cooling channel that would be applicable to a Higgs Factory and an Energy Frontier Muon Collider.

TUPFI065

Muon Ionization Cooling Experiment Step VI

cavity, coupling, vacuum, status

1499

D. Rajaram
Illinois Institute of Technology, Chicago, Illinois, USA
P. Snopok
IIT, Chicago, Illinois, USA

The Muon Ionization Cooling Experiment (MICE) is a demonstration experiment to prove the viability of cooling a beam of muons for use in a Neutrino Factory and Muon Collider. The ultimate Step VI configuration of the MICE cooling channel, a section of the one proposed in the Neutrino Factory Study II, will demonstrate a 10% reduction in transverse beam emittance measured at the level of 1%. This requires measuring emittance to 0.1%. This measurement will be made using all beam line elements present in the MICE Step IV configuration with the addition of two low-Z absorber modules and two RF-Coupling Coil (RFCC) modules. The RFCC modules each contain four normal-conducting low frequency (201 MHz) RF cavities with a guiding magnetic field provided by a large diameter coupling coil. Each of these cavities will require approximately 1 MW of RF power in a 1 ms pulse at a rate of 1 Hz. The experiment can explore a variety of combinations of momentum, beta function, magnetic field flip or non-flip configurations that will prove precious in the design of future cooling channels. The current status and progress toward Step VI are discussed.

TUPFI066

Muon Ionization Cooling Experiment Step VI

solenoid, simulation, site, target

1502

D. Rajaram
Illinois Institute of Technology, Chicago, Illinois, USA
P. Snopok
IIT, Chicago, Illinois, USA

In the Muon Ionization Cooling Experiment (MICE) the transverse emittance of the muon beam is reduced (muon cooling) by passing it through low-Z material, then through RF cavities to compensate for the energy loss. Transverse emittance reduction of the muon beam will be demonstrated for the first time in MICE Step IV configuration using liquid Hydrogen absorbers as well as a variety of solid absorbers. Current status and efforts towards Step IV are summarized, including hardware fabrication and testing, Monte Carlo simulations, track reconstruction algorithms.

TUPFI069

Influence of Proton Beam Emittances on Particle Production off a Muon Collider Target

target, proton, collider, factory

1511

X.P. Ding, D.B. Cline
UCLA, Los Angeles, California, USA
J.S. Berg, H.G. Kirk, H. K. Sayed
BNL, Upton, Long Island, New York, USA
V.B. Graves
ORNL, Oak Ridge, Tennessee, USA
K.T. McDonald
PU, Princeton, New Jersey, USA
N. Souchlas, R.J. Weggel
Particle Beam Lasers, Inc., Northridge, California, USA

Funding: Work supported in part by US DOE Contract NO. DE-AC02-98CHI10886.
A free-mercury-jet or a free-gallium-jet is considered for the pion-production target at a Muon Collider or Neutrino Factory. Based on a simple Gaussian incident proton beams with an infinitely large Courant-Snyder β parameters, we have previously optimized the geometric parameters of the target to maximize particle production initiated by incoming protons with kinetic energies (KE) between 2 and 16 GeV by using the MARS15 code. In this paper, we extend our optimization to focused proton beams with various transverse emittances. For the special cases of proton beams with emittances of 2.5, 5 or 10 μm-rad and a kinetic energy of 8 GeV, we optimized the geometric parameters of the target: the radius of the proton beam, the radius of the liquid jet, the crossing angle between the jet and the proton beam, and the incoming proton beam angle. We also study the influence of a shift of the beam focal point relative to the intersection point of the beam and the jet.

TUPFI078

Measurement of the Total Cross Section of Uranium-uranium Collisions at a Center-of-mass Energy of 192.8 GeV per Nucleon-pair

ion, beam-losses, luminosity, scattering

1529

W. Fischer, A.J. Baltz, M. Blaskiewicz, K.A. Drees, D.M. Gassner, Y. Luo, M.G. Minty, P. Thieberger, M. Wilinski
BNL, Upton, Long Island, New York, USA
I.A. Pshenichnov
RAS/INR, Moscow, Russia

Funding: Work supported by U.S. DOE under contract No DE-AC02-98CH10886 with the U.S. Department of Energy.
Heavy ion cross sections totaling several hundred barns have been calculated previously for the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC). These total cross sections are more than an order of magnitude larger than the geometric ion-ion cross sections, primarily due to Bound-Free Pair Production (BFPP) and Electro-Magnetic Dissociation (EMD). Apart from a general interest in verifying the calculations experimentally, an accurate prediction of the losses created in the heavy ion collisions is of practical interest for the LHC, where some collision products are lost in cryogenically cooled magnets and have the potential to quench these magnets. In the 2012 RHIC run uranium ions collided with each other at a center-of-mass energy of 192.8 GeV per nucleon-pair with nearly all beam losses due to collisions. This allows for the measurement of the total cross section and a comparison with calculations.

TUPFI084

RHIC Polarized Proton Operation for 2013

lattice, polarization, injection, resonance

1544

V.H. Ranjbar, L. A. Ahrens, E.C. Aschenauer, M. Bai, J. Beebe-Wang, M. Blaskiewicz, J.M. Brennan, K.A. Brown, D. Bruno, R. Connolly, T. D'Ottavio, K.A. Drees, Y. Dutheil, W. Fischer, C.J. Gardner, J.W. Glenn, X. Gu, M. Harvey, T. Hayes, H. Huang, R.L. Hulsart, A.I. Kirleis, J.S. Laster, C. Liu, Y. Luo, Y. Makdisi, G.J. Marr, A. Marusic, F. Méot, K. Mernick, R.J. Michnoff, M.G. Minty, C. Montag, J. Morris, S. Nemesure, P.H. Pile, A. Poblaguev, V. Ptitsyn, G. Robert-Demolaize, T. Roser, W.B. Schmidke, V. Schoefer, F. Severino, T.C. Shrey, D. Smirnov, K.S. Smith, D. Steski, S. Tepikian, D. Trbojevic, N. Tsoupas, J.E. Tuozzolo, G. Wang, M. Wilinski, K. Yip, A. Zaltsman, A. Zelenski, K. Zeno, S.Y. Zhang
BNL, Upton, Long Island, New York, USA
O. Eyser
UCR, Riverside, California, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The 2013 operation of the Relativistic Heavy Ion Collider (RHIC) marks the second year of running under the RHIC II era. Additionally this year saw the implementation of several important upgrades designed to push the intensity frontier. Two new E-lenses have been installed, along with a new lattice designed for the E-lens operation. A new polarized proton source which generates about factor of 2 more intensity was commissioned as well as a host of RF upgrades from a new longitudinal damper, Landau cavity in RHIC to a new low level RF and new harmonic structure for the AGS. We present an overview of the challenges and results from this years run.

TUPFI086

A Tapered Six Dimensional Cooling Lattice for a Muon Collider

collider, lattice, simulation, focusing

1547

D. Stratakis, R.C. Fernow, R.B. Palmer
BNL, Upton, Long Island, New York, USA

Designs for Neutrino Factories and Muon Colliders use ionization cooling to reduce the emittance of the muon beam prior to acceleration. Two lattices based on the original RFOFO ring design representing different configurations of the magnetic field are considered. One is with a flip magnetic field and one with a non-flip magnetic field configuration that is used to eliminate for possible space-charge effects. The details of the G4Beamline tracking studies of both channels are presented and compared to the independent ICOOL code.

TUPFI088

Space-charge Studies for Ionization Cooling Lattices

lattice, space-charge, collider, simulation

1553

D. Stratakis, R.B. Palmer
BNL, Upton, Long Island, New York, USA
D.P. Grote
LLNL, Livermore, California, USA

Funding: This work is funded by US Dept. of Energy grant numbers DE AC02-98CH10886
Intense muon beams provide a promising solution to a variety of applications ranging from nanotechnology to nuclear detections systems and from medical sciences to high energy physics. Production of such intense beam requires the beam to be cooled and ionization cooling via particle matter interaction is considered one of the most practical methods. Here a theoretical and numerical study on space-charge effects on such ionization cooling channels is presented. We show that space-charge can strongly affect the design of muon cooling systems by limiting their minimum cooling rate. Space-charge compensation solutions are discussed and the minimum cooling emittance as a function of the beam charge and pulse width is identified.

TUPME001

Effect of Self-consistency on Space Charge Induced Beam Loss

resonance, simulation, space-charge, controls

1556

G. Franchetti
GSI, Darmstadt, Germany

In long term storage space charge driven incoherent effect may lead to a slow beam diffusion that causes emittance growth and beam loss. However, when beam loss are relevant the full mechanism cannot be understood only driven by an incoherent effect. In this proceeding the issue of the self-consistency is discussed, and its impact presented for simplified examples and for the SIS100.

TUPME005

Preparations for Beam Tests of a CLIC Damping Wiggler Prototype at ANKA

wiggler, damping, target, storage-ring

1568

A. Bernhard, E. Huttel, P. Peiffer
KIT, Karlsruhe, Germany
A.V. Bragin, N.A. Mezentsev, V.M. Syrovatin, K. Zolotarev
BINP SB RAS, Novosibirsk, Russia
P. Ferracin, D. Schoerling
CERN, Geneva, Switzerland

The Compact Linear Collider (CLIC) will require ultra-low emittance electron and positron beams. The targeted emittance will be achieved by radiative damping in the CLIC damping rings. For an efficient damping high-field short-period superconducting damping wigglers will be employed. In the conceptual design phase of CLIC, the basic layout of these wigglers has been elaborated at CERN. In the course of the CLIC technical feasibility studies a full-scale damping wiggler prototype will be installed and tested in the ANKA storage ring. The device is currently under design and construction at the Budker Institute of Nuclear Physics, Russia. Above the magnetic requirements, the main design challenges for the prototype are scalability –- particularly of the cooling concept –-, modularity and the capability of sustaining a high radiative heat load. The experiments at ANKA aim at a validation of the technical concepts applied to meet these requirements. Beyond that an extended experimental program on beam dynamics and alternative technical solutions is envisaged. This contribution gives an overview over the current status of the project and the further planning.

TUPME010

High-intensity and Low-emittance Upgrade of 7-GeV Injector Linac towards SuperKEKB

positron, linac, electron, laser

1583

K. Furukawa, M. Akemoto, D.A. Arakawa, Y. Arakida, A. Enomoto, S. Fukuda, H. Honma, R. Ichimiya, N. Iida, M. Ikeda, E. Kadokura, K. Kakihara, T. Kamitani, H. Katagiri, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Miura, F. Miyahara, T. Mori, H. Nakajima, K. Nakao, T. Natsui, Y. Ogawa, S. Ohsawa, F. Qiu, M. Satoh, T. Shidara, A. Shirakawa, H. Sugimoto, T. Suwada, T. Takatomi, T. Takenaka, M. Tanaka, Y. Yano, K. Yokoyama, M. Yoshida, L. Zang, X. Zhou
KEK, Ibaraki, Japan
D. Satoh
TIT, Tokyo, Japan

After a decade of successful operation at KEKB a new electron/positron collider, SuperKEKB, is being constructed to commission within FY2014. It aims at a luminosity of 8 x 10³⁵ /s.cm², 40-times higher than that of KEKB, in order to study the flavor physics of elementary particles further, by mainly squeezing the beams at the collision point. The injector linac should provide high-intensity and low-emittance beams of 7-GeV electron and 4-GeV positron by newly installing a RF-gun, a flux concentrator, and a damping ring with careful emittance and energy management. It also have to perform simultaneous top-up injections into four storage rings by pulse-to-pulse beam modulations not to interfare between three facilities of SuperKEKB, Photon Factory and PF-AR. This paper describes the injector design decisions and present status of the construction.

TUPME014

Coherent Synchrotron Radiation Predicted at the SuperKEKB Damping Ring

damping, linac, vacuum, simulation

1595

H. Ikeda, M. Kikuchi, K. Ohmi, K. Oide, D. Zhou
KEK, Ibaraki, Japan

The damping ring of SuperKEKB is under construction in order to inject low emittance positron beam into the main ring. We calculated the bunch lengthening and the energy spread caused by the longitudinal wake, which is dominated by the CSR wake field. The result was within the tolerance level.

TUPME019

Simulation for Control of Longitudinal Beam Emittance in J-PARC MR

injection, bunching, simulation, acceleration

1610

M. Yamamoto, M. Nomura, A. Schnase, T. Shimada, F. Tamura
JAEA/J-PARC, Tokai-mura, Japan
E. Ezura, K. Hara, K. Hasegawa, C. Ohmori, A. Takagi, K. Takata, M. Toda, M. Yoshii
KEK, Ibaraki, Japan

The J-PARC MR receives a high intensity beam from the RCS. The designed longitudinal emittance of the RCS is 5 eVs, whereas the MR rf bucket has enough margin to accept up to 10 eVs. Although the RCS emittance can be increased by using PM method and a large emittance is desirable to increase the bunching factor and to avoid instability, it is difficult to receive such large emittance beam in the MR because of the MR kicker performance. We have performed the particle tracking simulation of longitudinal emittance control for enlarging the beam emittance by PM method and for keeping the bunching factor high using 2nd harmonic rf during the MR injection period.

TUPME021

Optimization Parameter Design of a Circular e⁺e⁻ Higgs Factory

luminosity, factory, synchrotron, collider

1616

D. Wang, Y.W. An, J. Gao, H. Geng, Y.Y. Guo, Q. Qin, N. Wang, S. Wang, M. Xiao, G. Xu, S.Y. Xu
IHEP, Beijing, People's Republic of China

Funding: NSFC:11175192
In this paper we will show a genral method of how to make an optimized parameter design of a circular e⁺e⁻ Higgs Factory by using analytical expression of maximum beam-beam parameter and beamstrahlung beam lifetime started from given design goal and technical limitations. A parameter space has been explored.

TUPME022

Study on the Single Bunch Transverse Emittance Growth in BAPS

wakefield, lattice, vacuum, wiggler

1619

J. Gao, D. Wang
IHEP, Beijing, People's Republic of China

Funding: Supported by the National Foundation of Natural Sciences Contract 11175192.
Beijing Advanced photon Source (BAPS) is a proposed next synchrotron radiation facility which has much smaller transverse emittance after SSRF in China, with 5 GeV energy and 1.5 km circumference. In order to explore how small the transverse emittance we can get on BAPS, this paper studies the single bunch transverse emittance growth due to short range wakefield according to J. Gao’ theory. The mechanism of wakefield induced single bunch emittance is explained first and then the transverse emittance at the design beam current is estimated. Also, the tolerances for the transverse loss factor and the vacuum chamber misalignment (or the closed orbit distortion) are presented.

TUPME025

Calculation of the Equilibrium Parameters for the Compact Ring of TTX

photon, scattering, electron, storage-ring

1625

H.S. Xu, W.-H. Huang, C.-X. Tang
TUB, Beijing, People's Republic of China
S.-Y. Lee
IUCEEM, Bloomington, Indiana, USA

Intra-Beam Scattering (IBS) can cause emittance growth in high intensity low energy beams. We study its effect on the compact low energy electron storage ring, proposed for Tsinghua Thomson Scattering X-ray source (TTX). For a single bunch with peak current at about 17A and re-entrant type normal conducting RF cavity with peak voltage at 15kV, the equilibrium horizontal and vertical emittances are 2.9 and 0.3 μm, and the rms momentum spread and bunch length are about 0.2%, and 23ps. In this paper, we report the methods and results of the IBS calculation.

TUPME030

Emittance Reconstruction from Measured Beam Sizes

coupling, simulation, optics, FEL

1640

J. Giner Navarro, A. Faus-Golfe, J. Fuentes, J. Navarro, J. Resta
IFIC, Valencia, Spain

In this paper we analyze the projected emittance (2D) and the intrinsic emittance (4D) reconstruction method by using the beam size measurements at different locations. We have studied analytically the conditions of solvability of the systems of equations involved in this process and we have obtained some rules about the locations of the measurement stations to avoid unphysical results. Presently, simulations are being made to test the robustness of the algorithm in realistic scenarios with high coupling and measurement errors. The special case of a multi-OTR system in ATF2 is being studied in much detail. The results of these studies will be very useful to better determine the location of the emittance measurement stations in the diagnostic sections of Future Linear Colliders.

TUPME034

Experimental Studies for Future LHC Beams in the SPS

injection, optics, brightness, space-charge

1652

H. Bartosik, T. Argyropoulos, T. Bohl, S. Cettour-Cave, J. Esteban Müller, W. Höfle, G. Iadarola, Y. Papaphilippou, G. Rumolo, B. Salvant, F. Schmidt, E.N. Shaposhnikova, H. Timko
CERN, Geneva, Switzerland
A.Y. Molodozhentsev
KEK, Ibaraki, Japan

The High Luminosity LHC (HL-LHC) project requires significantly higher beam intensity than presently accessible in the LHC injector chain. The aim of the LHC injectors upgrade project (LIU) is to prepare the CERN accelerators for the future needs of the LHC. Therefore a series of machine studies with high brightness beams were performed, assessing the present performance reach and identifying remaining limitations. Of particular concern are beam loading and longitudinal instabilities at high energy, space charge for beams with 50ns bunch spacing and electron cloud effects for beams with 25ns bunch spacing. This paper provides a summary of the performed studies, that have been possible thanks to the implementation of the SPS low gamma-transition optics.

TUPME042

The SPS as an Ultra-low Emittance Damping Ring Test Facility for CLIC

damping, wiggler, optics, target

1661

Y. Papaphilippou, R. Corsini, L.R. Evans
CERN, Geneva, Switzerland

In view of the plans for a future electron/positron linear collider based on the CLIC technology, an ultra-low emittance damping ring test facility is proposed, using the CERN SPS. Optics modification, required wiggler length and characteristics, energy and RF parameters are presented in order to reach CLIC performance requirements, including the effect of Intrabeam Scattering. Considerations about the necessary injected beam characteristics, its production and transfer through the existing CERN accelerator complex are also discussed.

TUPME045

Turn-by-turn Measurements in the KEK-ATF

synchrotron, damping, injection, betatron

1664

Y. Renier, Y. Papaphilippou, R. Tomás, M. Wendt
CERN, Geneva, Switzerland
N. Eddy
Fermilab, Batavia, USA
K. Kubo, S. Kuroda, T. Naito, T. Okugi, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan

The ATF damping ring has been upgraded with new read-out electronics for the beam position monitors (BPM), capable to acquire the beam orbits on a turn-by-turn basis, as well as in a high resolution averaging mode. The new BPM system allows to improve optic corrections and to achieve an even smaller vertical emittance (<2pm). Experimental results are presented based on turn-by-turn beam orbit measurements in the ring, for estimating the beta functions and dispersion along the lattice. A fast method to measure spectral line amplitude in a few turns is also presented, including the evaluation of chromaticity.

TUPME046

Performance of SPS Low Transition Energy Optics for LHC Ion Beams

optics, ion, scattering, space-charge

1667

F. Antoniou, G. Arduini, H. Bartosik, T. Bohl, S. Cettour Cave, K. Cornelis, D. Manglunki, Y. Papaphilippou
CERN, Geneva, Switzerland

An optics with low transition energy has been developed in the SPS for removing intensity limitations of the LHC proton beam and has become operational towards the second part of the 2012 LHC proton run. This optics was also used for filling the LHC with lead ions during the p/Pb run of the beginning of 2013. The impact of this optics in the performance of the LHC ion beam is studied here, especially with respect to collective effects, at the SPS injection energy. In particular, the potential gain of the increased beam sizes provided by this optics, with respect to losses and emittance blow up due to space-charge and Intrabeam Scattering (IBS) is evaluated. The measured lifetime is compared with the one provided by the Touschek effect and its interplay with RF noise is studied. The models are supported by measurements in the SPS and in the LHC flat bottom.

TUPME048

Imperfection Tolerances for On-line Dispersion Free Steering in the Main Linac of CLIC

linac, wakefield, quadrupole, simulation

1673

J. Pfingstner, A. Latina, D. Schulte
CERN, Geneva, Switzerland

Long-term ground motion misaligns the elements of the main linac of CLIC over time. Especially the misaligned quadrupoles create dispersion and hence the beam quality is decreased gradually due to an effect called chromatic dilution. Over longer time periods, orbit feedback systems are not capable to fully recover the beam quality and have to be supplemented by dispersion correction algorithms. In this paper, such and dispersion correction algorithm is presented, which is an extended version of the well-known dispersion free steering algorithm. This extended algorithm can recover the beam quality over long time scaled without stopping the accelerator operation (on-line). Tolerances for different imperfections of the system have been identified and a strong sensitivity to the resolution of the wake field monitors of the main linac accelerating structures has been identified. This problem can be mitigated by using a local excitation scheme as will be shown in this work.

TUPME050

Performance Comparison of Different System Identification Algorithms for FACET and ATF2

kicker, simulation, linac, alignment

1679

J. Pfingstner, A. Latina, D. Schulte
CERN, Geneva, Switzerland

Good system knowledge is an essential ingredient for the operation of modern accelerator facilities. For example, beam-based alignment algorithms and orbit feedbacks rely strongly on a precise measurement of the orbit response matrix. The quality of the measurement of this matrix can be improved over time by statistically combining the effects of small system excitations with the help of system identification algorithms. These small excitations can be applied in a parasitic mode without stopping the accelerator operation (on-line). In this work, different system identification algorithms are used in simulation studies for the response matrix measurement at ATF2. The results for ATF2 are finally compared with the results for FACET, latter originating from an earlier work.

TUPME055

Strawman Optics Design for the CERN LHeC ERL Test Facility

linac, optics, lattice, electron

1694

A. Valloni, O.S. Brüning, R. Calaga, E. Jensen, M. Klein, R. Tomás, F. Zimmermann
CERN, Geneva, Switzerland
S.A. Bogacz, D. Douglas
JLAB, Newport News, Virginia, USA

In preparation for a future Large Hadron electron Collider (LHeC) at CERN, an ERL test facility is foreseen as a test bed for SRF development, cryogenics, and advanced beam instrumentation, as well as for studies of ERL-specific beam dynamics. The CERN ERL test facility would comprise two linacs, each consisting of 4 superconducting 5-cell cavities at 802 MHz, and two return arcs on either side. With an RF voltage of 75 MeV per linac a final electron energy of about 300 MeV is reached. The average beam current should be above 6 mA to explore the parameter range of the future LHeC. In this paper we present a preliminary optics layout.

TUPME056

3.5 GeV Superconducting Stacking Ring for Compton Based Polarized Positrons Source of CLIC

positron, injection, damping, synchrotron

1697

E.V. Bulyak, P. Gladkikh, A.A. Kalamayko
NSC/KIPT, Kharkov, Ukraine
T. Omori, J. Urakawa, K. Yokoya
KEK, Ibaraki, Japan
L. Rinolfi, F. Zimmermann
CERN, Geneva, Switzerland

This paper describes 3.5 GeV superconducting storage ring dedicated to positron accumulation as part of a polarized positron source for CLIC, based on Compton scattering in a Compton storage ring. The superconducting stacking ring can provide a synchrotron damping time of order 250 microseconds. Together with combined injection scheme in the longitudinal and transverse plane, such a ring may solve the problem of accumulating a positron beam with efficiency close to 95 % and with the beam intensity required for CLIC.

TUPME059

Collisional Effects in Particle-in-Cell Beam-Beam Simulations

simulation, collider, luminosity, proton

1700

S. Paret, J. Qiang
LBNL, Berkeley, California, USA

Funding: This work was partially supported by the U.S. LARP and the NERSC of the U.S. Department of Energy under contract No. DE-AC02-05CH11231.
Self-consistent particle tracking simulations (strong-strong) can be used to investigate the deterioration of colliding beams in a storage ring. However, the use of a small number of macroparticles copmared to the real number of particles magnifies the collisional effects and causes numerical noise. In particular, predictions of the emittance lifetime suffer from this numerical noise. In order to produce usable emittance predictions, the contribution of numerical noise to the simulated emittance growth has to be known. In this paper, we apply a diffusion model to strong-strong beam-beam simulations to study the numerical noise driven emittance growth. The scaling of emittance growth with numerical and physical parameters is discussed.

TUPME060

Tune Studies with Beam-Beam Effects in LHC

resonance, simulation, luminosity, collider

1703

S. Paret, J. Qiang
LBNL, Berkeley, California, USA
R. Alemany-Fernandez, X. Buffat, R. Calaga, K. Cornelis, M. Fitterer, R. Giachino, W. Herr, A. Macpherson, G. Papotti, T. Pieloni, S. Redaelli, F. Roncarolo, M. Schaumann, R. Suykerbuyk, G. Trad
CERN, Geneva, Switzerland
R. Miyamoto
ESS, Lund, Sweden

Funding: This work was partially supported by the U.S. LARP and the NERSC of the U.S. Department of Energy under contract No. DE-AC02-05CH11231.
In high brightness colliders, the tune spread due to the collisions has a significant impact on the quality of the beams. The impact of the working point on emittance growth and beam lifetime has been observed in beam experiments in LHC. Strong-strong beam-beam simulations that were accomplished to better understand such observations are shown. Compared to experiments, wide ranged parameter scans can be done easily. Tune footprints and scans of the emittance growth obtained from simulations are discussed. Three cases are considered: Very high intensity, moderate intensity and collisions with separated beams.

TUPME061

Emittance Growth with Crab Cavity and Damper Noise in LHC

simulation, pick-up, resonance, damping

1706

S. Paret, J. Qiang
LBNL, Berkeley, California, USA

Funding: This work was partially supported by the U.S. LARP and the NERSC of the U.S. Department of Energy under contract No. DE-AC02-05CH11231.
Strong-strong beam-beam simulations are employed to investigate the noise sensitivity of the emittance in the future High Luminosity (HL)-LHC. Noise in the accelerator causes fluctuations of the bunch centroids at the interaction points (IPs) which cause emittance growth for large beam-beam parameters. Two noise sources are examined: Crab cavities and the transverse damper. The damper noise is adjusted to bring simulations in agreement with an emittance measurement in a past LHC run. Results from simulations with HL-LHC beam parameters using different noise levels, damper gains and working points are discussed.

TUPME066

CESR Low Emittance Upgrade with Combined Function Bends

wiggler, quadrupole, damping, focusing

1718

D. L. Rubin, Y. Li, A.A. Mikhailichenko, S. Wang
CLASSE, Ithaca, New York, USA

Funding: Work supported by the National Science Foundation and Department of Energy under contract numbers PHY-1002467, DMR-0936384 and DE-SC0006505
The Cornell Electron Storage Ring is the laboratory for the CESR Test Accelerator damping ring R&D program, and the source of x-rays for CHESS. A peculiarity of the layout of the storage ring is that horizontal emittance is generated predominantly by the strong bends in the sextant of the ring that was designed with a long straight to accommodate the interaction region required for operation as an electron-positron collider. By reconfiguring that single sextant we reduce the emittance by 60% to 20 nm-rad at 5.3 GeV for x-ray production and with damping wigglers to 1.3 nm-rad at 2.1 GeV for investigations of low emittance phenomena. The 35 meter radius of curvature, 3.2 meter long dipoles are refitted as combined function (vertically focusing) magnets to create simple achromats. The layout can accommodate six, 3 meter long undulators, in addition to the six existing superconducting damping wigglers. With reduced horizontal emittance and energy spread, the reconfiguration enhances the sensitivity of CESR to the emittance diluting effects that are the subject of the CesrTA study. Capability of the x-ray source is significantly improved with six new undulator beam lines.

TUPWA003

Beam Based Magnet Alignment for Emittance Coupling Minimization

sextupole, quadrupole, storage-ring, coupling

1724

R.T. Dowd, G. LeBlanc, Y.E. Tan
ASCo, Clayton, Victoria, Australia
K.P. Wootton
The University of Melbourne, Melbourne, Australia

Magnet misalignments give rise to field terms which can cause coupling between the horizontal and vertical beam motion and therefore emittance coupling. A series of beam based measurements have been developed at the Australian Synchrotron to accurately quantify quadrupole and sextupole alignments errors which cause coupling and where possible, correct them. Results showing an reduction in emittance coupling due to realignments of magnets based on these measurements will be presented. Limitations and general applicability of this method will also be discussed.

TUPWA004

Advanced Considerations for Designing Very High-intensity Linacs through Novel Methods of Beam Analysis, Optimization, Measurement & Characterisation

linac, space-charge, extraction, rfq

1727

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

Research in fundamental physics, nuclear physics or advanced materials, requires linear accelerators as irradiation sources with higher and higher beam intensity. In such machines, not only high beam power but also high space charge are the major challenges. This double concern often induces conflicting issues, which should be overcome from the accelerator design stage. It progressively appears that the usual methods are no more sufficient. Even new concepts are to be invented. With mega-watt beams, losses and also micro-losses must be minimised while with very strong space charge, few room can be reserved for beam diagnostics. New strategies for design and tuning are to be carried out. The beam itself can no more be described only by its classical values like emittance and Twiss parameters. Core and halo parts should be instead precisely defined and kept under surveillance. The beam phase space distribution itself becomes determinant, which is very far from waterbag or gaussian distributions. This paper aims at proposing new considerations for very high-intensity linacs while recalling the usual ones, from designing and tuning methods to beam definitions and characterisations.

TUPWA007

Method and Results of Systematic Beam Matching to a Periodic DTL

DTL, resonance, focusing, quadrupole

1733

L. Groening, W.A. Barth, P. Forck, I. Hofmann, S.G. Yaramyshev
GSI, Darmstadt, Germany
D. Jeon
IBS, Daejeon, Republic of Korea

Systematic investigations on high current 3d-beam matching to a periodic Alvarez-type DTL are reported. Twiss parameters at the entrance of a matching section to the periodic structure were concluded from transverse and longitudinal measurements. Periodic solutions in 3d were calculated including space charge using the measured rms emittances. The matching was performed by rms beam size tracking and employing a numerical routine to set the matching section, which comprises five quadrupoles and two bunchers. Matching allowed for significant emittance growth reduction and for verification of non-linear beam dynamics effects along the DTL.

TUPWA011

Investigation of Emittance Growth in a Small PET Cyclotron CYCIAE-14

resonance, cyclotron, extraction, simulation

1745

M. Li, Shizhong. An, T.J. Zhang
CIAE, Beijing, People's Republic of China

In order to satisfy the rapidly increased domestic needs for PET in China, a small medical cyclotron named CYCIAE-14 is designed and constructed in CIAE ( China Institute of Atomic Energy ) . As the beam intensity in CYCIAE-14 is high, the beam emittance should be controlled strictly in order to reduce the beam loss in the cyclotron. Precessional mixing and resonance crossing are the two main factors leading to emittance growth in the cyclotron with stripping extraction. In this paper, the physical mechanism of precessional mixing in a stripping extraction cyclotron is investigated. After that, the maximum allowable field errors in CYCIAE-14 are derived using the Hamiltonian formalism and numerical simulation, which provides a reference for the cyclotron design and field shimming.

TUPWA012

The Influence of the Magnetic Field Errors in CYCIAE-100 Cyclotron

resonance, cyclotron, simulation, TRIUMF

1748

H.J. Yao, M. Li, T.J. Zhang, J.Q. Zhong
CIAE, Beijing, People's Republic of China

The main magnet size of CYCIAE-100 is 2.31 m in height and 6.16 m in diameter and the outer radius of the sector is 2.0 m, and the total iron weight is about 415t. The magnetic filed can not be absolutely ideal because of imperfections during manufacturing and installation of this big magnet. Therefore the influence of the magnetic field errors on the beam behavior should be studied to provide the reference for magnet mapping and shimming. Magnetic field errors in a cyclotron will excite coherent oscillations through displacing the center of orbit or distorting the transverse phase space. This effect is especially important in the CYCIAE-100 cyclotron because there are a number of different turns in the extracted beam. The tolerances for the magnetic field errors are given in this paper based on analytic calculations and numerical simulations. The resonances vr=1, 2vr=2 driven by the 1st, 2nd harmonic magnetic field are considered, which will result in the radial emittance growth .Besides that, the resonances cause the vertical emittance growth are considered. The maximum allowable field errors for CYCIAE-100 are presented in this paper.

TUPWA013

Study of the C-ADS Longitudinal Beam Instabilities Caused by HOMS

HOM, linac, damping, simulation

1751

P. Cheng, Z. Li, J.Y. Tang, J.Q. Wang
IHEP, Beijing, People's Republic of China

The C-ADS accelerator is a CW proton linac which accelerates the beam to 1.5GeV. It has the characteristics of being very high beam power and very high reliability that are not posed by any of the existing proton linacs. The accelerator uses two families (β=0.63 and β=0.82 ) of elliptical five cell superconducting cavities. High Order Modes can severely limit the operation of these cavities. Monopole modes are found by Microwave Studio CST. Then the longitudinal instability caused by these monopole modes are primarily investigated with code bbusim, taking into account of effects like High Order Modes frequency spread, beam input jitters and other beam and RF parameters of the beams and cavities. Preliminary simulation results show that monopole modes induced instability is not a problem if High Order Modes frequency spread is not less than 1MHz. However, further investigations are necessary in order to make a critical decision such as whether HOM damper will be adopted. Study on the transverse case is under way.

TUPWA018

Local Compensation-Rematch for Element Failures in the Low Energy Section of C-Ads Accelerator

solenoid, cavity, linac, focusing

1760

B. Sun, Z. Li, J.Y. Tang, F. Yan
IHEP, Beijing, People's Republic of China

Due to the requirement of high reliability and availability for the C-ADS accelerators, a fault tolerance design is pursued. The effects of transverse focusing element failures in different locations have been studied and the schemes of compensation by means of local compensation have been investigated. After one transverse element failure especially in the low energy section happens, some new methods have been purposed by which the new settings of the neighbouring solenoids and the cavities can be set, and the Twiss parameters and energy can be approximately recovered to that of the nominal ones at the matching point. We find that the normalized RMS emittance in transverse and longitudinal planes have no obvious growth after applying the compensation in each section of the main linac. When we make study on the compensation-rematch for the RF cavity failures, the TraceWin code has been used that doesn’t consider the phase change during the cavity resetting, so a code named LOCCOM, which is based on MATLAB, is developed and used to compensate the error on arrival-time at the matching point.

TUPWA019

Comparison of Tracking Simulation with Experiment on the GSI UNILAC

DTL, simulation, linac, space-charge

1763

X. Yin
IHEP, Beijing, People's Republic of China
W.A. Barth, W.B. Bayer, L. Groening, I. Hofmann, S.G. Richter, S.G. Yaramyshev
GSI, Darmstadt, Germany
A. Franchi
CERN, Geneva, Switzerland
A.C. Sauer
IAP, Frankfurt am Main, Germany

In the European framework “High Intensity Pulsed Proton Injector” (HIPPI), the 3D linac code comparison and benchmarking program with experiment have been initialed. PARMILA and HALODYN are involved in this work. Both of these codes have been developed and used for linac design and beam dynamics studies. In this paper, we compare the simulation results with experiment results which was carried out on the UNILAC Alvarez DTL. And discuss physics aspects of the different linac design and beam dynamics simulation codes.

TUPWA020

The Implementation of Equipartitioning in the Proton Linac Code PADSC

space-charge, lattice, quadrupole, linac

1766

Y.L. Zhao, S. Fu, Z. Li
IHEP, Beijing, People's Republic of China

The high intensity accelerator projects place extremely stringent requirements on particle loss, since even very small losses can lead to unacceptably high levels of radioactivity that can hinder or prevent hands-on maintenance. Such losses are known to be associated with emittance growth and beam halo. Non-equipartitioning contributes a lot for emittance growth and beam halo. The present equipartitioning realization has assumed that the emittance and space charge force are keeping constant, which will induce errors. The implementation in the proton linac code PADSC does equipartitioning optimization according to the real space charge force and emittance in the quasi period lattice.

TUPWA022

Beam Dynamics Design of a 325 MHz RFQ

rfq, cavity, proton, simulation

1772

F.J. Jia, J.E. Chen, G. Liu, Y.R. Lu, X.Q. Yan
PKU, Beijing, People's Republic of China
B.Q. Cui, J.H. Li, G.H. Wei
CIAE, Beijing, People's Republic of China

The beam dynamic design of a 325 MHz Radio Frequency Quadrupole (RFQ) is presented in this paper. This 4-vane RFQ will accelerate pulsed proton beam from 30 keV to 3 MeV with repetition frequency of 1 MHz. A 1 MHz chopper and a 5 MHz buncher are arranged in the Low-Energy-Beam-Transport (LEBT) to produce the injected beam. The beam length at the RFQ entrance is about 3 ns, and the energy-spread is about 10%. The code of PARMTEQM is used to simulate RFQ structure. The design should realize high transmission for very high intensity beam meanwhile low emittance growth and relatively short length should be kept.

TUPWA025

DESIGN STUDIES OF THE C-ADS MAIN LINAC WITH ONLY SPOKE CAVITIES

linac, proton, simulation, space-charge

1781

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

The China ADS(C-ADS) project undertaken by the Chinese Academy of Science is based on superconducting proton linac. The design goal is to accelerate 10mA CW proton beam up to 1.5GeV. The accelerator includes an injector section and a main superconducting linac. Two injectors are under studying by IHEP and IMP respectively. In this paper, an alternative design of the main linac with full spoke cavity base on the beam characteristics from IMP injectorⅡis described. In addition, multi-particle beam dynamics simulations have been performed using TraceWin code to estimate the space charge effect.

TUPWA034

On the Choice of Linac Parameters for Minimal Beam Losses

space-charge, linac, resonance, beam-losses

1787

M. Eshraqi
ESS, Lund, Sweden
J.-M. Lagniel
GANIL, Caen, France

In high intensity linear accelerators, the tune spreads induced by the space-charge forces in the radial and longitudinal planes are key parameters for halo formation and beam losses. For matched beams they are the parameters governing the number of resonances (including coupling resonances) which affect the beam and determine the respective sizes of the stable and halo areas in phase space. The number and strength of the resonances excited in mismatched beams leading to even higher amplitude halos are also directly linked to the tune spreads. In this paper, the equations making the link between the basic linac parameters (rf frequency, zero-current phase advances, beam intensity and emittances) and the tune spreads are given. A first analysis of the way these linac parameters can be chosen to minimize the tune spreads is presented. The parameters of ESS linac are used for this study.

TUPWA038

Equilibrium Bunch Density Distribution with Passive Harmonic Cavities in the MAX IV 3 GeV Storage Ring

cavity, impedance, storage-ring, damping

1790

P.F. Tavares, Å. Andersson, A. Hansson
MAX-lab, Lund, Sweden

The MAX IV storage rings will use third harmonic cavities operated passively to lengthen the bunches and alleviate collective instabilities. These cavities are an essential ingredient in the MAX IV design concept and are required for achieving the final design goals in terms of stored current, beam emittance and beam lifetime. This paper reports on fully self-consistent calculations of the longitudinal bunch density distribution in the MAX IV 3 GeV storage ring, which indicate that up to a factor 5 increase in RMS bunch length is achievable with a purely passive system.

TUPWA040

Loss of Landau Damping for Inductive Impedance in a Double RF System

damping, synchrotron, simulation, impedance

1796

T. Argyropoulos, E.N. Shaposhnikova
CERN, Geneva, Switzerland
A.V. Burov
Fermilab, Batavia, USA

In this paper the thresholds of the loss of Landau damping due to the presence of inductive impedance in a single and double harmonic RF systems are determined, both from calculations and particle simulations. High harmonic RF system, operating in bunch lengthening mode is used in many accelerators with space charge or inductive impedance to reduce the peak line density or stabilize the beam. An analytical approach, based on emerging of the discrete Van Kampen modes, shows that improved stability in a double RF system can be achieved only below some critical value of longitudinal emittance. Above this threshold, a phase shift of more than 15 degrees between the two RF components is proven to stabilize the bunch. These results, confirmed also by particle simulations, are able to explain now observations during the ppbar operation of the SPS. The thresholds in bunch shortening mode as well as in a single RF case are compared with this regime.

TUPWA044

Longitudinal Coupled-Bunch Oscillation Studies in the CERN PS

damping, feedback, kicker, cavity

1808

H. Damerau, S. Hancock, M.M. Paoluzzi
CERN, Geneva, Switzerland
M. Migliorati, L. Ventura
Rome University La Sapienza, Roma, Italy

Longitudinal coupled-bunch oscillations are an important limitation for the high-brightness beams accelerated in the CERN PS. Up to the present intensities they are suppressed by a dedicated feedback system limited to the two dominant oscillation modes. In view of the proposed installation of a wide-band feedback kicker cavity within the framework of the LHC Injectors Upgrade project (LIU), measurements have been performed with the existing damping system with the aim of dimensioning the new one. Following the excitation of well-defined oscillation modes, damping times and corresponding longitudinal kick strength are analysed. The paper summarizes the results of the observations and gives an outlook on the expected performance with the new coupled-bunch feedback.

TUPWA046

Experimental Results from the Test Beam Line in the CLIC Test Facility 3

simulation, quadrupole, lattice, extraction

1814

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

In the CLIC two-beam scheme, the main beam is accelerated by rf power provided by energy extraction from a secondary drive beam. This energy is extracted in decelerators, and the first prototype decelerator is the Test Beam Line in the CLIC Test Facility 3. The line is currently equipped with 12 Power Extraction and Transfer Structures (PETS), which allows for extracting up to 40% of the beam energy. We correlate the measured deceleration with predictions from the beam current and the rf power produced in the PETS. We also discuss recent bunch length measurements and how it influences the deceleration. Finally we look at the evolution of the transverse emittance.

TUPWA049

Short High-Intensity Bunches for Plasma Wakefield Experiment AWAKE in the CERN SPS

optics, impedance, proton, plasma

1820

H. Timko, T. Argyropoulos, H. Bartosik, T. Bohl, J. Esteban Müller, E.N. Shaposhnikova
CERN, Geneva, Switzerland
A.V. Petrenko
BINP SB RAS, Novosibirsk, Russia

Obtaining the shortest possible bunch length in combination with the smallest transverse emittances and highest bunch intensity – this is the wish list of the proton-bunch driven, plasma wakefield acceleration experiment AWAKE currently under feasibility study at CERN. A few measurement sessions were conducted to determine the achievable bunch properties and their reproducibility. To obtain a short bunch length, the bunches were rotated in longitudinal phase space using the maximum available RF voltage prior to extraction. Measurements were carried out in two optics with different transition energies. The main performance limitation is longitudinal beam instability that develops during the acceleration ramp. With lower transition energy, beam stability is improved, but the bucket area is smaller for the same voltage. Based on the results obtained, we shall discuss the choice of optics, the impact of longitudinal instabilities, the importance of reproducibility, as well as options for improving the bunch parameters.

TUPWA050

Effect of Transverse Coupling on Asymmetric Cooling in Compton Rings

laser, coupling, electron, betatron

1823

E.V. Bulyak
NSC/KIPT, Kharkov, Ukraine
J. Urakawa
KEK, Ibaraki, Japan
F. Zimmermann
CERN, Geneva, Switzerland

Fast cooling of bunches circulating in a Compton ring is achieved by placing the collision point between electron bunches and laser pulses in a dispersive section and by, in addition, introducing a transverse offset between the laser pulse and the electron-beam closed orbit. Growth of the emittance in the dispersive transversal direction due to the additional excitation of betatron oscillations limits this type of cooling. Here we present the results of further studies on the fast cooling process, looking at the effect of the coupling of the transverse (betatron) oscillations. We first show theoretically that the transverse betatron coupling shortens the cooling time and hence reduces the steady-state energy spread of the electron beam, as well as the quantum losses. The theoretical estimates are then validated by simulations. Finally, a proof-of-principle experiment at the KEK ATF Damping Ring is proposed.

TUPWA054

PXIE End-to-end Simulations

rfq, simulation, cryomodule, solenoid

1829

J.-F. Ostiguy, J.-P. Carneiro, V.A. Lebedev, A. Saini, N. Solyak
Fermilab, Batavia, USA

Funding: US DOE contract DE-AC02-76CH03000.
Construction of PXIE, (Project-X Injector Experiment) has recently begun. The goal is to validate the design of the injector and low energy acceleration front-end for a future Project-X. PXIE operates in CW mode and consists in an ion source, a magnetically focused LEBT, a 162.5 MHz RFQ, a MEBT equipped with high bandwidth traveling wave kickers, a cryomodule equipped with 162.5 MHz half-wave resonators and a single cryomodule based on 325 MHz spoke resonators. The arrangement is meant to be closely representative of a future Project-X front end, and will include a variety of diagnostics. In this contribution we present detailed end-to-end tracking simulations. In particular, we examine possible impact of the RFQ longitudinal distribution, neutralization effects in the LEBT as well as of various imperfections in the MEBT on losses in the first superconducting cavities.

TUPWA063

Dependence of Vertical Beam Dynamics Influenced by Electron Clouds at CesrTA on Variations in Bunch Spacing and Vertical Chromaticity

electron, positron, synchrotron, feedback

1847

R. Holtzapple, R.F. Campbell, E.L. Holtzapple
CalPoly, San Luis Obispo, California, USA
M.G. Billing, K.R. Butler, G. Dugan, M.J. Forster, B.K. Heltsley, G. Ramirez, N.T. Rider, J.P. Shanks, K.G. Sonnad
CLASSE, Ithaca, New York, USA
J.W. Flanagan
KEK, Ibaraki, Japan

Funding: Work supported by DOE Award DE-FC02-08ER41538, NSF Award PHY-0734867, PHY-1068662 and the Lepton Collider R&D Coop. Agreement: NSF Award PHY-1002467
Experiments have been performed on the Cornell Electron-Positron Storage Ring Test Accelerator (CesrTA) to probe the interaction of the electron cloud with a 2-Gev stored positron beam. The purpose of these experiments was to characterize the beam–electron cloud interactions by varying the vertical chromaticity and bunch spacing. These experiments were performed on a 30-bunch positron train, at a fixed current of 0.75mA/bunch, where the bunch spacing was varied between 4 and 28ns at three different vertical chromaticity settings. The vertical beam dynamics of the stored beam, in the presence of the electron cloud, was quantified using the x-ray beam size monitor (xBSM) that is used to measure the bunch-by-bunch, turn-by-turn vertical beam size of the bunch trains. In this paper, we report the results from these experiments and discuss the effects of the electron cloud on the CesrTA beam dynamics.

TUPWA064

Suppression of Halo Formation in FODO Focusing Channel with Nonlinear Focusing

quadrupole, multipole, focusing, space-charge

1850

Y.K. Batygin, A. Scheinker
LANL, Los Alamos, New Mexico, USA

Averaging method was applied to analyze focusing properties of a quadrupole FODO channel with inserted multipole lenses. General expression for averaged focusing potential is obtained as a function of position of multipole lenses with respect to FODO quadrupole lenses. Obtained results were applied to the problem of intense beam transport in combined FODO structure. Numerical and analytical treatments of high-brightness beam dynamics with suppressed space-charge induced halo formation are presented.

TUPWA065

Design Issues of Low Energy Beam Transport

solenoid, focusing, space-charge, ion

1853

Y.K. Batygin
LANL, Los Alamos, New Mexico, USA

Low energy beam transport (LEBT) is an important element of ion accelerator facilities to provide beam matching between ion source and accelerator structure, perform required beam diagnostics measurements, dispose extra particle components, and create necessary time structure of the beam. Most of existing ion LEBT are based on solenoid focusing. Design criteria for ion LEBT with magnetostatic focusing are discussed. Dynamics in LEBT is optimized in terms of maximizing acceptance of the channel and transported beam current, and minimizing spherical aberrations in solenoids and space charge induced beam emittance growth.

TUPWA066

Space Charge Neutralization of Low Energy H⁻ Beam

space-charge, simulation, ion, ion-source

1856

Y.K. Batygin, I.N. Draganić, C.M. Fortgang, G. Rouleau
LANL, Los Alamos, New Mexico, USA

LANSCE Ion Source Test Stand is used for systematic study of H⁻ source performance and details of low energy beam transport. It includes cesiated, multicusp-field, surface production H⁻ ion source, focusing solenoids, slit-collector emittance stations, 4.5o bending magnet, and electrostatic deflector. Series of experiments were performed to measure space charge neutralization of low energy H⁻ beam. Measurements were done for 80 keV and 35 keV H⁻ beams at various pressure of residual gas. Results of measurements are compared with results of beam dynamics simulations to determine level of space charge neutralization. Applicability of theoretical models of beam neutralization is discussed.

TUPWA067

Beam Emittance Growth Effects in High-intensity RFQ

resonance, rfq, linac, space-charge

1859

Y.K. Batygin, R.W. Garnett, L. Rybarcyk
LANL, Los Alamos, New Mexico, USA

Beam dynamics in an RFQ are strongly affected by coupling between transverse and longitudinal particle oscillations. The adiabatic process of high-intensity bunched beam formation results in equipartitioning in the RFQ, which determines the longitudinal beam emittance. Avoiding parametric resonances is an important design criterion to prevent significant emittance growth of the beam. Manufacturing errors can result in beam emittance growth and reduction of beam transmission. This paper will present the results of a study where analytical and numerical evaluations were performed to determine the effect of the aforementioned factors on beam quality in a high-current RFQ.

TUPWA074

Studies of Ion Beam Instabilities for Low Energy RHIC Operations with Electron Cooling

ion, electron, simulation, impedance

1871

G. Wang, M. Blaskiewicz, V. Litvinenko
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Electron cooling has the potential to compensate the emittance growth of the circulating ion beam due to intra-beam scattering at low energy. A test of electron cooling for RHIC low energy operations has been planned at IP2. Apart from the wakefield from the environment, the coherent interaction between the electron beam and ion beam could also play a role for the instability threshold. This work presents studies of ion beam stabilities in presence of coherent electron-ion interactions for the planned low energy RHIC electron-cooling test using the simulation code TRANFT.

TUPWO001

A New 5BA Low Emittance Lattice for Sirius

lattice, dipole, sextupole, coupling

1874

L. Liu, N. Milas, A.H.C. Mukai, X.R. Resende, A.R.D. Rodrigues, F. H. de Sá
LNLS, Campinas, Brazil

Sirius is a third-generation low emittance synchrotron light source under construction at LNLS, the Brazilian Synchrotron Light Laboratory. A new 5BA lattice was designed in replacement for the previous TBA lattice with the aim to reduce the emittance to sub-nm.rad values. The new design has a circumference of 518 m with 20 achromatic straight sections and a natural emittance of 0.28 nm.rad at 3 GeV for the bare lattice (without IDs). The dipoles combine low 0.58 T field magnets for the main beam deflection with a 2 T short superbend magnet sandwiched in the center dipole. This creates a longitudinal dipole gradient that is used both to lower the emittance and to provide hard X-ray dipole sources.

TUPWO005

Survey of Beam Optics Solutions for the MLS Lattice

optics, quadrupole, lattice, cavity

1883

M. Ries, J. Feikes, T. Goetsch, G. Wüstefeld
HZB, Berlin, Germany

The Metrology Light Source (MLS) is an electron storage ring containing 24 quadrupole magnets which can be powered individually. Fully exploring the capabilities of the machine optics by tracking or experiment would be very time consuming. Therefore the quadrupoles were combined in five families and a numerical brute force approach was used to scan for areas of stable solutions in the scope of linear beam optics. In order to get information on the expected beam lifetimes for each generated optics, a model for the Touschek lifetime was implemented. Simulation results as well as experimental tests of selected optics will be presented.

TUPWO009

Decoupling Capabilities Study of the Emittance Transfer Section

solenoid, quadrupole, coupling, stripper

1895

C. Xiao, O.K. Kester
IAP, Frankfurt am Main, Germany
L. Groening, O.K. Kester, M.T. Maier
GSI, Darmstadt, Germany

Flat beams are those which feature unequal emittances in the horizontal and vertical phase space. The present paper is on the planning of the experimental proof of principle. Detailed simulations of the experiment, initially based on linear matrix transformations, are performed. The remarkable flexibility of the set-up w.r.t. to decoupling is addressed, as it can provide an one-knob tool to set the horizontal and vertical emittance partitioning. It was found that the decoupling capability of the set-up is remarkably flexible and the impact and discussion of this finding is treated in a dedicated section

TUPWO010

Optimal Twiss Parameters for Emittance Measurement in Periodic Transport Channels

betatron, simulation, beam-transport, focusing

1898

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

From the point of view of the optimality criteria introduced in *, we study in this paper the procedure of emittance measurement in periodic beam transport channels.
* V.Balandin, W.Decking, N.Golubeva. “Invariant Criteria for the Design of Multiple Beam Profile Emittance and Twiss Parameters Measurement Sections”, These Proceedings.

TUPWO011

Invariant Criterion for the Design of Multiple Beam Profile Emittance and Twiss Parameters Measurement Sections

betatron, coupling, simulation, optics

1901

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

By studying errors in the reconstructed beam parameters as functions of the errors in the beam size measurements, we introduce an optimality criteria which can be used for the design and comparison of multiple beam profile emittance and Twiss parameters measurement sections and which is independent from the position of the reconstruction point.

TUPWO012

Relations Between Projected Emittances and Eigenemittances

beam-transport, electron, quadrupole, coupling

1904

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

We give necessary and sufficient conditions which two sets of positive real numbers must satisfy in order to be realizable as eigenemittances and projected emittances of a beam matrix. The information provided by these conditions sets limits on what one can to achieve when designing a beam line to perform advanced emittance manipulations (for example, round-to-flat beam transformations).

TUPWO016

Beam Dynamics Design of 3 MeV Medium Energy Beam Transport for Beam Intensity Upgrade of J-PARC Linac

DTL, simulation, cavity, linac

1916

T. Maruta
KEK/JAEA, Ibaraki-Ken, Japan
M. Ikegami
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

The J-PARC linac has a plan to upgrade its beam power in the summer 2013. This plan includes the replacement of the front-end components (ion source and 3 MeV RFQ) to increase the peak current from present 30 mA to 50 mA. Since it results in the different injection beam profile to medium energy beam transport (MEBT), which locates the RFQ downstream, we designed the beam dynamics of MEBT. In this presentation, we disscuss the new design of beam dynamics in MEBT.

TUPWO019

A Local Achromatic Design of C-ADS MEBT2

linac, bunching, controls, cavity

1922

H. Geng, Z. Guo, Z. Li, C. Meng, S. Pei, J.Y. Tang
IHEP, Beijing, People's Republic of China

The accelerator of China Accelerator Driven Sub-critical system consists of two injectors to ensure its high reliability. The Medium Energy Beam Transport line-2 is an essential part of the accelerator to transport and match the beam from either injector to the main linac. This paper presents a local achromatic design, which uses four bending magnets, for CADS MEBT2. It is found that both transverse and longitudinal emittance growths can be well controlled below 15% from MEBT2 entrance to the exit of the following superconducting spoke-021 section. The beam dynamics of MEBT2 will be discussed and the multi-particle tracking results will also be shown.

TUPWO020

Error Analysis for C-ADS MEBT2

cavity, linac, beam-transport, solenoid

1925

H. Geng, Z. Guo, Z. Li, C. Meng, S. Pei, J.Y. Tang
IHEP, Beijing, People's Republic of China

A local achromatic scheme has been developed for C-ADS MEBT2. This paper presents the error analysis results for this MEBT2 scheme. The effects of magnet and cavity misalignment, static and dynamic errors of electric and magnetic field, the displacement of the input beam as well as the initial mismatches of the incoming beam will be studied. Beam trajectory correction scheme will also be discussed.

TUPWO022

Space Charge Effects Study and Optimization in CSNS/LRBT

space-charge, lattice, linac, injection

1928

Z.P. Li, N. Huang, W.B. Liu, S. Wang
IHEP, Beijing, People's Republic of China

The linac to ring beam transport line (LRBT) of China Spallation Neutron Source (CSNS) connecting the linac and the rapid cycling synchrotron (RCS) transports 80 MeV negative hydrogen ions (H⁻) beams for RCS injection. Space charge effect in LRBT is significant due to small emittance and high current density of the beam, which is a major cause of emittance growth and beam loss. An achromatic transverse optical matching was performed by TRACE 3D code. Emittance growths of beams with different initial distributions in different LRBT lattices were studied separately. Simulation results show that the LRBT design with triplet can mitigate the emittance growth by lattice optimization of the front matching section and no beam loss occurs at 15mA. The location and parameters of the debuncher in LRBT were also optimized to reduce the momentum spread and energy jitter.

TUPWO029

Beam Line Design at the CAEP THz Free Electron Laser

electron, cavity, laser, FEL

1937

P. Li, W. Bai, H. Wang
CAEP/IAE, Mianyang, Sichuan, People's Republic of China
X. Li
TUB, Beijing, People's Republic of China

China Academy of Physics (CAEP) is currently building a THz Free Electron Laser (THz-FEL) which serves as a radiation light sourse used for research in a variety of experimental fields. In this paper, we present the design of the beam line, which was accomplished using PARMELA and TRANSPORT code simulations. The accelerator consists of a 350 kV photocathode DC gun in conjunction with one cryomodule containing two 4-cell superconductiong RF cavities. The energy of the elctron beam is 7~8 MeV, and the maximum of the average beam current is 5 mA. A transverse emittance typically below 10 pi mm.mrad can be achieved.

TUPWO031

Double-mini-beta Optics for the SSRF Storage Ring

optics, dynamic-aperture, storage-ring, injection

1943

S.Q. Tian, B.C. Jiang, M.Z. Zhang, Z.T. Zhao
SINAP, Shanghai, People's Republic of China

The two long straight sections of the SSRF storage ring will be installed by dual canted in-vacuum insertion devices in the near future. In order to get high brightness and maintain good machine performance, the vertical beta function must be reduced by a triplet of quadrupole between the two source points, which is the so-called double-mini-beta optics. We have designed this kind of optics for SSRF, and the results are presented in this paper.

TUPWO033

Effects Estimation of Superconducting Wiggler in SSRF

lattice, dynamic-aperture, optics, quadrupole

1946

Q.L. Zhang, B.C. Jiang, S.Q. Tian, W.Z. Zhang, Z.T. Zhao
SINAP, Shanghai, People's Republic of China

Superconducting wiggler (SW) may greatly impact on the beam dynamics in a storage ring. The effects of a 4.5T SW has been studied in SSRF including impaction on the emittance and the energy spread. To keep an undegraded storage ring performance, a local achromatic lattice is considered. The combat between the damping effect of the SW and emittance growth of local achromatic lattice is the main concern of this paper. Other effects (tune shift, beta beating, dynamics aperture, etc.) with the SW are also simulated and optimized in this paper.

TUPWO037

Design Study of the Low Energy Beam Transport System at RISP

rfq, solenoid, beam-transport, ion

1955

E.-S. Kim
KNU, Deagu, Republic of Korea
J. Bahng
Kyungpook National University, Daegu, Republic of Korea
J. Qiang
LBNL, Berkeley, California, USA

We present the design status of LEBT for the RISP that consists of two 90 degree dipoles, a multi-harmonic buncher, pair solenoids, electrostatic quadrupoles and a high voltage platform. After ECR-IS with an energy of 10 keV/u, heavy-ion beams are selected by achromatic bending systems and then be bunched in the LEBT. A multi-harmonic buncher is used to achieve a small longitudinal emittance in the RFQ. We show the results on the optics design by using the TRANSPORT code and the beam tracking of two-charge beams by using the code IMPACT. We present the results and issues on beam dynamics simulaitons in the designed LEBT system.

TUPWO038

Start-to-end Simulations for Heavy-ion Accelerator of RISP

linac, rfq, simulation, proton

1958

E.-S. Kim, S.W. Jang
KNU, Deagu, Republic of Korea
J. Bahng, J.G. Hwang
Kyungpook National University, Daegu, Republic of Korea
B. Choi, D. Jeon, H.J. Kim, H.J. Kim
IBS, Daejeon, Republic of Korea

RAON has been designed as a facility for rare isotope accelerator at Korea. The aceelerator consists of 28 GHz superconducting ion source, LEBT, RFQ, MEBT, superconducting linac and HEBT. The linac accelerates ion beams to 200 MeV/u with a beam power of 400 kW. Start-to-End simulations are performed from ECR-IS to HEBT and the detailed beam simulation results are presented. The beam dynamics issues are also discussed.

TUPWO041

Beam Size and Emittance Measurements during the ALBA Booster Ramp

booster, linac, injection, dipole

1964

U. Iriso, G. Benedetti
CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain

The beam emittance in the ALBA Booster is damped from 50·10^-6 m*rad to 10^-9 m*rad during the energy acceleration from 110 MeV to 3 GeV. The synchrotron radiation monitor installed in a dipole magnet provides the transverse beam size evolution along the energy ramp, which is then used to calculate the emittance evolution during the full booster cycle (from injection to extraction). In this report, we present the experimental set-up and technique of this measurement, and discuss the agreement between the measured parameters and theoretical values.

TUPWO059

Reducing Emittance of a H⁻ Beam in a Solenoid-based Low-energy Beam Transport through Numerical Modeling

simulation, solenoid, rfq, electron

2000

J. von Stecher, D.L. Bruhwiler, B.T. Schwartz, S.A. Veitzer
Tech-X, Boulder, Colorado, USA
B. Han, M.P. Stockli
ORNL, Oak Ridge, Tennessee, USA

Funding: This work is supported by the US DOE Office of Science, Office of Basic Energy Sciences, including grant No. DE-SC0000844
A solenoid-based low-energy beam transport (LEBT) subsystem is under development for the H⁻ linac front end of the Spallation Neutron Source. The LEBT design includes MHz frequency chopping of the partially neutralized H⁻ beam that can potentially lead to beam instabilities. We report results of numerical modeling using the parallel Vorpal framework for 3D electrostatic particle-in-cell (PIC) to simulate H⁻ beam dynamics in the LEBT, over multiple chopping events. We detail how the addition of a positively biased potential barrier near the entrance of the chopper can improve LEBT performance by eliminating chopper-induced emittance increases over many chopping events.
DLB is now at University of Colorado, Boulder

TUPWO060

Flat Electron Bunch Compression at the Advanced Superconducting Test Accelerator

quadrupole, simulation, cathode, solenoid

2003

C.R. Prokop, D. Mihalcea, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
B.E. Carlsten
LANL, Los Alamos, New Mexico, USA
P. Piot, Y.-E. Sun
Fermilab, Batavia, USA

Funding: This work is supported by LANL LDRD #20110067DR and by the U.S. DOE contracts DE-FG02-08ER41532 and DE-AC02-07CH11359.
The generation of flat beam using round-to-flat beam conversion of an incoming canonical-angular-momentum dominated electron beam could have important application in the field of advanced acceleration techniques and accelerator-based light source. In this paper we explore the temporal compression of flat beams and especially compare the resulting phase space dilutions with the case of round beam. Finally, we propose and detail a possible experiment to investigate the flat-beam bunch compression at the Advanced Superconducting Test Accelerator currently in construction at Fermilab.

TUPWO063

Reducing HLS-II Emittance by Radiation Damping Partition Factor Exchange

wiggler, storage-ring, damping, lattice

2009

J.Y. Li
FEL/Duke University, Durham, North Carolina, USA
W. Li, G. Liu, W. Xu
USTC/NSRL, Hefei, Anhui, People's Republic of China
Y. Li
BNL, Upton, Long Island, New York, USA

Funding: The Introduction of Outstanding Technological Talents Program of Chinese Academy of Sciences, 2010.
In this paper, we present a preliminary study on using a Robinson wiggler, a wiggler with transverse gradient, to reduce the horizontal beam emittance of the Hefei Light Source II (HLS-II) storage ring. A proof-of-principle study demonstrates that it is possible to further reduce the horizontal beam emittance by 50\% using a 2-meter long Robinson wiggler installed on a dispersive straight section. This encouraging result suggests a feasible option to significantly improve the HLS-II performance at a relative low cost and without significant modification to its global configuration in the near future.

TUPWO067

Start-to-end Particle Tracking of the FACET Accelerator

linac, klystron, wakefield, simulation

2018

N. Lipkowitz, F.-J. Decker, G.R. White, M. Woodley, G. Yocky
SLAC, Menlo Park, California, USA

Funding: Work supported by Department of Energy contract DE-AC02-76SF00515.
The Facility for Advanced aCcelerator Experimental Tests (FACET) consists of the first two-thirds of the SLAC two-mile linac followed by a final focus and experimental end station. To date, wakefield-dominated emittance growth and dispersion in the linac, as well as dispersive and chromatic effects in the final focus have precluded regular reliable operation that meets the design parameters for final spot size. In this work, a 6-D particle tracking code (Lucretia) is used to simulate the complete machine, with input parameters taken directly from saved machine configurations. Sensitivities of various tuning parameters to the final spot sizes are compared with measurements taken from the real machine, and a set of tuning protocols is determined to improve regular machine operation.

TUPWO068

Performance Improvements of the SLAC Linac for the FACET Beam

linac, quadrupole, klystron, injection

2021

F.-J. Decker, N. Lipkowitz, E. Marín, Y. Nosochkov, J. Sheppard, M.K. Sullivan, Y. Sun, M.-H. Wang, G.R. White, U. Wienands, M. Woodley, G. Yocky
SLAC, Menlo Park, California, USA

Funding: Work supported by U.S.Department of Energy, Contract DE-AC02-76SF00515.
Two thirds of the SLAC Linac is used to generate a short, intense electron beam for the FACET experiments. The emittance growth along the Linac is a major concern to finally get small spot sizes for these experiments. There are two different approaches to get the required small emittances: a) lengthy iterative global tuning technique, and b) trying to identify locations of the main sources of the emittance growth and reducing their effect locally. How these approaches help to get good beam performances is discussed.

WEXB101

Optics Optimization for Reducing Collective Effects and Raising Instability Thresholds in Lepton and Hadron Rings

optics, synchrotron, collective-effects, brightness

2033

Y. Papaphilippou, F. Antoniou, H. Bartosik
CERN, Geneva, Switzerland

This paper covers recent progress in the design of optics solutions to minimize collective effects such as beam instabilities, intra-beam scattering or space charge in hadron and lepton rings. The necessary steps are reviewed for designing the optics of high-intensity and high-brightness synchrotrons but also ultra-low emittance lepton storage rings, whose performance is strongly dominated by collective effects. Particular emphasis is given to proposed and existing designs illustrated by simulations and beam measurements.

Slides WEXB101 [24.511 MB]

WEODB103

Current Status of PAL-XFEL Project

FEL, undulator, gun, klystron

2074

H.-S. Kang, J.H. Han, T.-H. Kang, C. Kim, D.E. Kim, S.H. Kim, I.S. Ko, H.-S. Lee, K.-H. Park, S.J. Park
PAL, Pohang, Kyungbuk, Republic of Korea

The PAL-XFEL is a 0.1-nm hard X-ray FEL construction project which started from 2011 with a total budget of 400 M$. The PAL-XFEL is designed to have three hard X-ray undulator lines at the end of 10-GeV linac and a dog-leg branch line at 3 GeV point for two soft X-ray undulator lines. The three-bunch compressor lattice (3-BC) is chosen to have large flexibility of operation, making it possible to operate soft X-ray FEL undulator line simultaneously and independently from hard X-ray FEL line. Self seeding to achieve the FEL radiation bandwidth of below 5x10^-5 is baseline for the hard X-ray FEL line. Polarization control will be available by using the PU + EPU layout for the soft X-ray FEL line. The overview of the project with current status is presented.

Slides WEODB103 [8.332 MB]

WEPWA001

Wigglers at Danfysik

wiggler, electron, damping, radiation

2123

C.W.O. Ostenfeld, M. Pedersen
Danfysik A/S, Taastrup, Denmark

In the past 2 years, a number of insertion devices have been designed, assembled and tested at Danfysik. They are used for a variety of applications at free electron lasers and synchrotron radiation facilities. In this paper, we highlight 3 different wiggler projects: A 2.0 T wiggler for Astrid-II in Århus, Denmark, a fixed-gap electromagnetic wiggler for Helmholtz Center Dresden-Rossendorf, and 6 identical damping wigglers for NSLS-2 at Brookhaven National Laboratory (BNL). For the Astrid-2 facility in Aarhus, Denmark, we have designed and built a 6 period wiggler, with a peak field of 2.0 T. The magnetic design and performance is presented and discussed. As part of the ELBE THz facility, at Helmholtz Center Dresden-Rossendorf, we have designed and built a fixed-gap electromagnetic wiggler, with 300 mm period length, and a peak field of 0.39 T. We present the design and magnetic results. For the NSLS-2 project at BNL, damping wigglers are an integral part of the design, both as a means of reducing the emittance, but also as a source of intense radiation sources for users. We present the mechanical and magnetic design, as well as magnetic results obtained for the wigglers.

WEPWA018

Pulsed Sextupole Injection for BAPS

injection, sextupole, septum, storage-ring

2168

Y. Jiao, G. Xu
IHEP, Beijing, People's Republic of China

In this paper we present the physical design of the pulsed sextupole injection system for Beijing Advanced Photon Source (BAPS) with an ultralow emittance. The BAPS ring lattice is designed in such a way that two injection options are allowed, i.e., with septum and pulsed sextupole in different drift spaces or in the same drift space. For both options optimal conditions are obtained for high injection efficiency. It is found that the available efficiency in a storage ring with limited acceptance can be affected by position-dependent dispersive effect induced by the pulsed sextupoles.

WEPWA023

Design of 14 MeV LINAC for THz Source Based FEL

gun, linac, FEL, quadrupole

2181

Y.J. Pei, G. Feng, Y. Hong, G. Huang, D. Jia, K. Jin, C. Li, J. Li, S. Lu, L. Shang
USTC/NSRL, Hefei, Anhui, People's Republic of China
Q.S. Chen, M. Fan, T. Hu, Y.Q. Xiong, H. Zeng
HUST, Wuhan, People's Republic of China
B. Qing, Z.X. Tang, X.L. Wei
USTC, Hefei, Anhui, People's Republic of China
L.G. Shen, F. Zhang
USTC/PMPI, Hefei, Anhui, People's Republic of China

Abstract THz wave have many special performances, such as it can penetrate deep into many organic materials without the damage associated with ionizing radiation such as X-ray, it can be used to distinguish between materials with varying water content, because THz radiation is absorbed by water. In part researchers lacked reliable sources of THz, so develop new THz sources is important now. So far there were many kind of THz Source, one of them is THz source based a FEL that can produce high power (~kW). This paper will describe the design of a LINAC of 14MeV which is used for FEL to produce THz radiation. The LINAC is mainly composed of a novel EC-ITC RF gun, compensation coil, constant gradient accelerating structure, beam diagnostic system and so on. Main design parameters are as following: Energy 7~15MeV Beam current (macro pulse) 571mA (micro pulse) 30~40° Bunch length 5~7ps Charge per bunch 200~300pC Normalized emittance ≤10mm.mrad Energy spread(rms) ≤0.5%

WEPWA040

Options for PAL-XFEL Injector Operation

laser, gun, FEL, cathode

2217

J.H. Han
PAL, Pohang, Kyungbuk, Republic of Korea
M.S. Chae
POSTECH, Pohang, Kyungbuk, Republic of Korea

Present designs of the PAL-XFEL injector assume a 120 MV/m peak field at the cathode in the gun and a flat-top longitudinal drive-laser profile. As accelerating field in the gun decreases and laser shape becomes imperfect, beam quality degradation takes place. On the other hand, by reducing accelerating field in the gun and by relaxing drive-laser shaping requirement the stability of the injector can be increased. We study various options for operating conditions of the injector with relaxed RF and drive-laser parameters.

WEPWA043

Construction of Injector Test Facility (ITF) for the PAL XFEL

gun, laser, controls, klystron

2220

S.J. Park, H. J. Choi, T. Ha, J.H. Han, J.H. Hong, W.H. Hwang, H.-S. Kang, T.-H. Kang, D.T. Kim, J.M. Kim, S.-C. Kim, I.S. Ko, B.H. Lee, H.-S. Lee, W.W. Lee, C.-K. Min, Y.J. Park, Y.G. Son
PAL, Pohang, Kyungbuk, Republic of Korea
M.S. Chae
POSTECH, Pohang, Kyungbuk, Republic of Korea

Funding: Work supported by the Ministry of Education, Science and Technology (MEST) in Korea.
An injector test facility (ITF) for the PAL-XFEL has been successfully constructed and its commissioning is under way. The facility is to demonstrate beam performances required by the PAL XFEL (beam energy of 139 MeV, projected rms emittance of < 0.5 mm mrad @ 200 pC, and beam repetition rate of 60 Hz) with good enough stabilities. We have constructed a dedicated building for the facility in which a radiation-shielding tunnel (19.2-m long, 3.5-m wide, and 2.4-m high inner space), a klystron-modulator gallery, a laser room, and a control room are installed. The injector consists of an in-house-developed photo-cathode rf gun, a 30-mJ Ti:Sa laser system, two accelerating structures (as well as two sets of klystron-modulator systems), and various diagnostics as well as magnets & instrumentations. The installation of a transverse deflecting cavity (S-band, 10-fs resolution) and a laser heater is scheduled in 2013. In this article we report on the facility construction and some of the early commisisoning results.

WEPWA051

Extraction Beam Line for Light Sources

extraction, injection, kicker, optics

2232

M. Aiba, M. Böge, T. Garvey, N. Milas, A. Saá Hernández, A. Streun
PSI, Villigen PSI, Switzerland

Most of measurements, with circulating beam in a ring, to determine transverse and longitudinal phase space volume are rather indirect although it is of importance to characterize these beam parameters for better understanding the machine. Direct measurements may be performed when the beam is extracted to a beam line, where destructive methods are available. However, light sources can tolerate internal beam dumping and thus do not have an extraction line in general. We, therefore, propose a diagnostic dedicated extraction line, motivated by precise determination of the geometrical vertical emittance, which can be a few pm or even less and general comparisons of direct and indirect measurements. Such an extraction beam line has been realized in several accelerator facilities, e.g. KEK-ATF. The idea is, however, to equip a compact beam line, which fits into the existing tunnel and allows us to measure transverse and longitudinal emittances. We present possible design of an extraction beam line assuming typical light source parameters.

WEPWA065

A Non-linear Injection Kicker for Diamond Light Source

kicker, injection, quadrupole, septum

2268

T. Pulampong, R. Bartolini
JAI, Oxford, United Kingdom
R. Bartolini
Diamond, Oxfordshire, United Kingdom

Ultra-low emittance lattices will operate with reduced dynamics apertures. New injection schemes are currently investigated in order to guarantee sufficient injection efficiency. A promising candidate is a pulsed kicker with a nonlinear magnetic field. The studies presented in this paper prove that this kicker allows injection with reduced dynamic aperture and provide minimal perturbation of the stored beam during Top-Up injection. Plans to install such a device at the Diamond light source are outlined.

WEPWA075

High-gain X-ray FELs using a Transverse Gradient Undulator in an Ultimate Storage Ring

FEL, undulator, electron, storage-ring

2286

Y.T. Ding, P. Baxevanis, Y. Cai, Z. Huang, R.D. Ruth
SLAC, Menlo Park, California, USA

An “ultimate” storage ring based on PEP tunnel has been designed to achieve diffraction limited emittance (at 1.5 Angstrom)[*]. With sufficient peak current, the beam brightness of such an “ultimate” storage ring may be sufficient to drive a short-wavelength, high-gain FEL. However, the large energy spread intrinsic to storage rings hinders the FEL applications for x-ray wavelengths. To overcome this problem, we adopt the transverse-gradient undulator concept[**][***] to study a high-gain FEL in an ultimate storage ring. Using PEP-X as an example, we showed from simulations that a high-gain FEL at the photon energy 1keV with a peak power of a few hundred megawatts can be achieved within a saturation length of 100 meters.
* Y. Cai et al., Phys. Rev. ST Accel. Beams 15, 054002 (2012).
** T. Smith et al., J. Appl. Phys. 50, 4580 (1979)
*** Z. Huang, Y. Ding and C. B. Schroeder, Phys. Rev. Lett 109, 204801 (2012).

WEPWA078

Compact Accelerator Design for a Compton Light Source

cavity, electron, gun, photon

2292

T. Satogata, K.E. Deitrick, J.R. Delayen, B.R.P. Gamage, K.G. Hernández-Chahín, C.S. Hopper, G.A. Krafft, R.G. Olave
ODU, Norfolk, Virginia, USA
K.G. Hernández-Chahín
DCI-UG, León, Mexico
G.A. Krafft, T. Satogata
JLAB, Newport News, Virginia, USA

Funding: Partially authored by Jefferson Science Associates, LLC under U.S. DOE contract NO. DE-AC05-06OR23177.
A compact electron accelerator suitable for Compton source applications is in design at the Center for Accelerator Science at Old Dominion University and Jefferson Lab. The design includes a KE=1.55 MeV low-emittance, optimized superconducting electron gun; a 23.45 MeV linac with multi-spoke 4.2 K superconducting cavities; and transport that combines magnetic longitudinal bunch compressor and transverse final focus. We report on the initial designs of each element, including end to end simulations with ASTRA and elegant, and expected beam parameters.

WEPWA083

Results of NSLS-II Linac Commissioning

linac, solenoid, dipole, quadrupole

2301

R.P. Fliller, A. Blednykh, J. Choi, M.A. Davidsaver, J.H. De Long, F. Gao, C. Gardner, Y. Hu, G. Jahnes, W. Jew, J. Klug, P. Marino, D. Padrazo, L. Pharr, R. Rainer, G. Ramirez, P. Ratzke, R. Raynis, J. Rose, M. Santana, S. Seletskiy, T.V. Shaftan, J. Shah, G. Shen, O. Singh, V.V. Smaluk, C. Sorrentino, K. Vetter, G.M. Wang, G.J. Weiner, X. Yang, L.-H. Yu, E. Zeitler
BNL, Upton, Long Island, New York, USA
K. Dunkel, J.H. Hottenbacher, B. Keune, A. Metz, C. Piel
RI Research Instruments GmbH, Bergisch Gladbach, Germany

Funding: This manuscript has been authored by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The NSLS-II linac is a 200 MeV normal conducting linac procured as a turn key system from Research Instruments. The linac and associated transport lines were installed at BNL in the winter of 2012. Commissioning activities started March 26 and lasted for 2.5 months. In this report we discuss the successful commissioning results of the linac, issues encountered, and the remaining work that needs to be accomplished for NSLS-II booster commissioning.

WEPWO007

Shape Optimization of a SRF Injector Cavity

cavity, solenoid, cathode, electron

2322

J.K. Sekutowicz
DESY, Hamburg, Germany
W.C. Grabowski, R. Nietubyć, T. Wasiewicz
NCBJ, Świerk/Otwock, Poland

In this contribution we present studies on the shape optimization of 1.6-cell cavity with solenoid for a 1-mA class photo injector, meant as an electron source for FEL facilities. The main criterion for the optimization was the lowest slice emittance. Inclination angle of the cavity back wall, solenoid position and magnetic field, amplitude of the accelerating field, and emission phase were varied in these studies in order to find the minimum of slice emittance at the distance of 1 m from a photocathode, located in center of the cavity back wall

WEPWO061

Readiness for the Cornell ERL

cathode, cavity, linac, laser

2447

G.H. Hoffstaetter, A.C. Bartnik, I.V. Bazarov, D.H. Bilderback, M.G. Billing, J.D. Brock, J.A. Crittenden, L. Cultrera, D.S. Dale, J. Dobbins, B.M. Dunham, R.D. Ehrlich, M. P. Ehrlichman, R. Eichhorn, K. Finkelstein, E. Fontes, M.J. Forster, S.J. Full, F. Furuta, D. Gonnella, S.W. Gray, S.M. Gruner, C.M. Gulliford, D.L. Hartill, Y. He, R.G. Helmke, K.M.V. Ho, R.P.K. Kaplan, S.S. Karkare, V.O. Kostroun, H. Lee, Y. Li, M. Liepe, X. Liu, J.M. Maxson, C.E. Mayes, A.A. Mikhailichenko, H. Padamsee, J.R. Patterson, S.B. Peck, S. Posen, P. Quigley, P. Revesz, D.H. Rice, D. Sagan, J. Sears, V.D. Shemelin, D.M. Smilgies, E.N. Smith, K.W. Smolenski, A.B. Temnykh, M. Tigner, N.R.A. Valles, V. Veshcherevich, A.R. Woll, Y. Xie, Z. Zhao
CLASSE, Ithaca, New York, USA

Funding: Supported by NSF award DMR-0807731 and NY State
Energy-Recovery Linacs (ERLs) are proposed as drivers for hard x-ray sources because of their ability to produce electron bunches with small, flexible cross sections and short lengths at high repetition rates. Cornell University has pioneered the design and hardware for ERL lightsources. This preparatory research for ERL-lightsource construction will be discussed. Important milestones have been achieved in Cornell's prototype ERL injector, including the production of a prototype SRF cavity that exceeds design specifications, the regular production of long-lived and low emittance cathodes, the acceleration of ultra-low emittance bunches, and the world-record of 65 mA current from a photoemission DC gun. We believe that demonstration of the practical feasibility of these technologies have progressed sufficiently to allow the construction of an ERL-based lightsource like that described in [erl.chess.cornell.edu/PDDR].

WEPEA014

Recent Electron Cloud Studies in the SPS

electron, injection, simulation, vacuum

2525

G. Iadarola, H. Bartosik, M. Driss Mensi, H. Neupert, G. Rumolo, M. Taborelli
CERN, Geneva, Switzerland
G. Iadarola
Naples University Federico II, Science and Technology Pole, Napoli, Italy

It is important to qualify the present status of the SPS with respect to the electron cloud before the Long Shutdown of the CERN accelerator complex, which will take place in 2013-2014. Therefore several electron cloud studies were performed during the 2012 run in order to get a full characterization of the behavior of the SPS with the LHC-type beams with 25 ns bunch spacing, which can be very sensitive to electron cloud effects. The collected information should allow to understand up to which extent this long period without beam operation - and the related interventions on the machine - will degrade the present conditioning state of the SPS, which has been achieved by “scrubbing” over several years. Several measurements with different beam conditions have been collected also on the electron cloud detectors installed in the machine. These results, in combination with detailed simulation studies, will provide the basis for defining strategies of electron cloud mitigation as required for the production of future high intensity and high brightness beams within the LHC Injectors Upgrade (LIU) project.

WEPEA023

Space Charge Effects for Different CSNS/RCS Working Points

resonance, lattice, simulation, space-charge

2549

S.Y. Xu, N. Wang, S. Wang
IHEP, Beijing, People's Republic of China

The China Spallation Neutron Source (CSNS) operates at 25 Hz repetition rate with the design beam power of 100 KW. CSNS consists of an 80-MeV linac and a 1.6-GeV Rapid Cycling Synchrotron (RCS). Due to the high beam density and high repetition rate for CSNS/RCS, the rate of beam loss must be controlled to a very low level. The major source of beam loss is associated with resonances. Thus, choosing he best suitable working points on the tune diagram is important to reach low beam loss. Different tune areas are explored and compared by considering resonances and the effects of space charge, which can drive particles into the excited resonances. Different working points are simulated and compared by using the codes ORBIT and SIMPSONS.

WEPEA024

Combine Effects of Space Charge and Chromaticity Sextupoles at CSNS/RCS

sextupole, simulation, space-charge, acceleration

2552

S.Y. Xu, S. Wang
IHEP, Beijing, People's Republic of China

Most high current proton synchrotrons, such as The Rapid Cycling Synchrotron (RCS) of The China Spallation Neutron Source (CSNS), are operated under the transition energy, and the natural chromaticity is small. These proton synchrotrons can work without chromatic correction. To reduce the tune spread produced by the chromaticity, chromatic correction is considered by using chromaticity sextupoles for this type of proton synchrotrons, such as J-PARC and SNS. Many chromatic correction schemes are compared for the CSNS/RCS, and the harmonic sextupoles are considered to correct nonlinear effect of chromaticity sextupoles. The dynamic aperture is obtained by particle tracking, and the combine effects of sextupole field and space charge effects are investigated by using the code ORBIT and SIMPSONS.

WEPEA031

Slow extraction design in HIMM

extraction, synchrotron, septum, resonance

2567

J. Shi, W.P. Chai, J.W. Xia, J.C. Yang, Y.J. Yuan
IMP, Lanzhou, People's Republic of China

A heavy ion medical machine(HIMM) is proposed for cancer therapy in Lanzhou, China. The slow extraction design of the synchrotron is introduced in this paper. Eight sextupoles are used, four of them are for correcting the chromaticity and the rest for driving the 3rd-order resonance. In order to save the aperture of vacuum chamber, a 3-magnet bump is adopted during the extraction process. The phase space map in the entrance of the electrostatic septum and the last 3 turns' particle trajectory before particle extraction are given.

WEPEA033

Optimization of Injector System for Early Commissioning Phase of Compact-ERL.

laser, space-charge, solenoid, gun

2573

J.G. Hwang, E.-S. Kim
Kyungpook National University, Daegu, Republic of Korea
T. Miyajima
KEK, Ibaraki, Japan

Injector system of Compact-Energy Recovery Linear accelerator, which is currently develping in Photon Factory of KEK at Japan, consists of the photo-cathode DC gun, two solenoids, a 1.3 GHz buncher ,three 1.3 GHz 2 cell injector cavities, 5 quadrupole magnet and merger section. Target values of beam produced by the injector system are kinetic energy of 5 MeV, the normalized transverse emittance of under 0.1 mm-mrad and the bunch length of under 3 ps with the 7.7 pC charge per bunch and the repetition rate of 1.3 Ghz. In this low energy region, the effect of the space charge is dominated to cause the emittance growth. The optimization is performed by using MOGA (Multi-Object Genetic Algorithm) with code GPT to consider the effect of space charge under optimization. The code General Particle Tracer (GPT) is a 3D Paricle-In-Cell(PIC) code based on multi-layer object-oriented design. Using this method with code GPT, the target values was achieved at the exit of the merger section such as the normalized emittance of 0.1 mm-mrad with bunch length of 3 ps and kinetic energy of 5 MeV.

WEPEA036

Spin Tune Decoherence Effects in Electro- and Magnetostatic Structures

betatron, sextupole, acceleration, synchrotron

2579

Y. Senichev, R. Maier, D. Zyuzin
FZJ, Jülich, Germany
N.V. Kulabukhova
St. Petersburg State University, St. Petersburg, Russia

In Electric Dipole Moment search experiments with polarized beams the coherence of spin oscillations of particles has a crucial role. The decoherent effects arise due to spin tune dependence on particle energy and particle trajectory in focusing-deflecting fields. They are described through the n-th order spin tune aberrations. Since the first order is suppressed by RF field, the second order plays crucial role. It depends on the orbit lengthening and on the odd order field components. We consider the spin decoherence effects and methods of their compensation in different channels, electrostatic, magnetostatic linking the decoherence effects with common characteristics such as the momentum compaction factor, the chromaticity and others.

WEPEA042

The PS Upgrade Programme: Recent Advances

injection, electron, resonance, extraction

2594

S.S. Gilardoni, S. Bart Pedersen, C. Bertone, N. Biancacci, A. Blas, D. Bodart, J. Borburgh, P. Chiggiato, H. Damerau, S. Damjanovic, J.D. Devine, T. Dobers, M. Gourber-Pace, S. Hancock, A. Huschauer, G. Iadarola, L.A. Lopez Hernandez, A. Masi, S. Mataguez, E. Métral, M.M. Paoluzzi, S. Persichelli, S. Pittet, S. Roesler, C. Rossi, G. Rumolo, B. Salvant, R. Steerenberg, G. Sterbini, L. Ventura, J. Vollaire, R. Wasef, C. Yin Vallgren
CERN, Geneva, Switzerland
M. Migliorati
University of Rome "La Sapienza", Rome, Italy

The LHC Injectors Upgrade project (LIU) has been initiated to improve the performances of the existing injector complex at CERN to match the future requirements of the HL-LHC. In this framework, the Proton Synchrotron (PS) will undergo fundamental changes for many of its main systems: the injection energy will be increased to reduce space-charge effects, the transverse damper will be improved to cope with transverse instabilities the RF systems will be upgraded to accelerate higher beam intensity and brightness. These hardware improvements are triggered by a series of studies meant to identify the most critical performance bottlenecks, like space charge, impedances, longitudinal and transverse instabilities, as well as electron-cloud. Additionally, alternative production schemes for the LHC-type beams have been proposed and implemented to circumvent some of the present limitations. A summary of the most recent advances of the studies, as well as the proposed hardware improvements is given.

WEPEA044

RF Manipulations for Higher Brightness LHC-type Beams

injection, brightness, controls, extraction

2600

H. Damerau, A. Findlay, S.S. Gilardoni, S. Hancock
CERN, Geneva, Switzerland

In order to increase the transverse brightness of beams for the LHC, ever more complicated RF manipulations have been proposed in the PS machine in order to reduce the intensity demands per PS batch on the upstream PS Booster. Several schemes based on cascades of batch compression, bunch merging, as well as the more routine bunch splitting have been successfully commissioned and higher brightness beams have been delivered to the downstream accelerators for measurement. Despite all this complexity, longitudinal and transverse beam quality are well preserved. In addition, to fully profit from the brightness of all four PS Booster rings, the injection of twice 4 bunches into harmonic 9 buckets in the PS has been made operational as an alternative to the usual double-batch transfer of 4+2 bunches into harmonic 7. This paper summarizes the new beam production schemes, their implementation in the PS low-level RF system and the experimental results.

WEPEA046

Experimental Observations from the LHC Dynamic Aperture Machine Development Study in 2012

dynamic-aperture, beam-losses, injection, octupole

2606

M. Giovannozzi, S. Cettour Cave, R. De Maria, M. Ludwig, A. Macpherson, S. Redaelli, F. Roncarolo, M. Solfaroli Camillocci, W. Venturini Delsolaro
CERN, Geneva, Switzerland

In view of improving the understanding of the behaviour of the dynamic aperture and to benchmark the numerical simulations performed so far, two experimental sessions have been scheduled at the LHC. The observations of the first sessions have been reported elsewhere[1], while in this paper the latest observations in terms of beam currents, blm losses and beam sizes will be described. The octupolar spool pieces have been used to artificially reduce the dynamic aperture and then induced slow beam losses. Alternating signs have been used in order to probe different configurations. Finally, scans over the strength of the decapolar spool pieces have been performed too.
[1] M. Giovannozzi et al., “First Experimental Observations from the LHC Dynamic Aperture Experiment”, in proceedings of IPAC12, p. 1362

WEPEA052

Investigations on CERN PSB Beam Dynamics with Strong Direct Space Charge Effects Using the PTC-ORBIT Code

simulation, space-charge, resonance, injection

2621

V. Forte, E. Benedetto, C. Carli, M. Martini, B. Mikulec, E. Métral, F. Schmidt
CERN, Geneva, Switzerland
A.Y. Molodozhentsev
KEK, Ibaraki, Japan

The CERN PS Booster (PSB) is the first synchrotron of the LHC injector chain consisting out of four superposed rings and providing beam for many users. As part of the LIU project, the machine will be upgraded. Space charge and resonances are serious issues for the good quality of the beam at injection energy. Consequently simulations are needed to track the beam in the machine taking into account space charge effects: PTC-ORBIT has been used as tracking code. This paper presents simulations results compared with the measurements for machine performances evaluation and code-benchmarking purposes.

WEPEA053

Progress with the Upgrade of the SPS for the HL-LHC Era

electron, kicker, extraction, simulation

2624

B. Goddard, T. Argyropoulos, W. Bartmann, H. Bartosik, T. Bohl, F. Caspers, K. Cornelis, H. Damerau, L.N. Drøsdal, L. Ducimetière, J. Esteban Müller, R. Garoby, M. Gourber-Pace, W. Höfle, G. Iadarola, L.K. Jensen, V. Kain, R. Losito, M. Meddahi, A. Mereghetti, V. Mertens, O. Mete, E. Montesinos, Y. Papaphilippou, G. Rumolo, B. Salvant, E.N. Shaposhnikova, M. Taborelli, H. Timko, F.M. Velotti
CERN, Geneva, Switzerland
E. Gianfelice-Wendt
Fermilab, Batavia, USA

The demanding beam performance requirements of the HL-LHC project translate into a set of requirements and upgrade paths for the LHC injector complex. In this paper the performance requirements for the SPS and the known limitations are reviewed in the light of the 2012 operational experience. The various SPS upgrades in progress and still under consideration are described, in addition to the machine studies and simulations performed in 2012. The expected machine performance reach is estimated on the basis of the present knowledge, and the remaining decisions that still need to be made concerning upgrade options are detailed.

WEPEA056

Design and Beam Measurements of Modified Fast Extraction Schemes in the CERN PS for Installing a Dummy Septum to Mitigate Ring Irradiation

extraction, septum, kicker, closed-orbit

2633

C. Hernalsteens, H. Bartosik, L.N. Drøsdal, S.S. Gilardoni, M. Giovannozzi, A. Lachaize, Y. Papaphilippou, A. Ulsroed
CERN, Geneva, Switzerland

The proposed Multi-Turn Extraction (MTE) for the CERN PS allows to reduce the overall extraction losses for high intensity beams. The required longitudinal structure of the proton beam induces unavoidable beam losses at the magnetic extraction septum. The installation of a dummy septum with an appropriate shielding has been proposed to localise losses and to shadow the magnetic septum. Such a device, located in the extraction region, imposes tight constraints on the available beam aperture. Modified extraction schemes have been proposed and in this paper they will be presented and discussed in detail together with the measured performance.

WEPEA062

Progress in ELENA Design

extraction, electron, vacuum, antiproton

2651

S. Maury, W. Bartmann, P. Belochitskii, H. Breuker, F. Butin, C. Carli, T. Eriksson, R. Kersevan, S. Pasinelli, G. Tranquille, G. Vanbavinckhove
CERN, Geneva, Switzerland
W. Oelert
FZJ, Jülich, Germany

The Extra Low Energy Antiproton ring (ELENA) is a small ring at CERN which will be built to increase substantially the number of usable (or trappable) antiprotons delivered to experiments for studies with antihydrogen. The report shows the progress in the ELENA design. The choice of optics and ring layout inside of AD hall is given. The main limitations for beam parameters at extraction like intra beam scattering and tune shift due to space charge are discussed. The electron cooler plays key role in ELENA both for efficient deceleration as well as for preparing extracted beam with parameters defined by experiments. The other important systems like beam vacuum, beam instrumentations and others are reviewed as well.

WEPEA070

Space Charge Effects and Limitations in the Cern Proton Synchrotron

resonance, space-charge, proton, injection

2669

R. Wasef, G. Arduini, H. Damerau, S.S. Gilardoni, S. Hancock, C. Hernalsteens, A. Huschauer, F. Schmidt
CERN, Geneva, Switzerland
G. Franchetti
GSI, Darmstadt, Germany

Space charge produces a large incoherent tune-spread which, in presence of betatronic resonances, could lead to beam losses and emittance growth. In the CERN Proton Synchrotron, at the current injection kinetic energy (1.4 GeV) and even at the future kinetic energy (2 GeV), space charge is one of the main limitations for high brightness beams and especially for the future High-Luminosity LHC beams. Several detailed studies and measurements have been carried out to improve the understanding of space charge limitations to determine the maximum acceptable tune spread and identify the most important resonances causing losses and emittance growth.

WEPEA071

Performance Limitations in the Lhc Due to Parasitic Beam-Beam Encounters - Parameter Dependence, Scaling, and Pacman Effects

dynamic-aperture, beam-beam-effects, luminosity, target

2672

T. Pieloni
EPFL, Lausanne, Switzerland
X. Buffat, R. Calaga, R. Calaga, R. Giachino, W. Herr, E. Métral, G. Papotti, G. Trad
CERN, Geneva, Switzerland
D. Kaltchev
TRIUMF, Vancouver, Canada

We studied possible limitations due to the long-range beam-beam effects in the LHC. With a large number of bunches and collisions in all interaction points, we have reduced the crossing angles (separation) to enhance long-range beam-beam effects to evaluate their influence on dynamic aperture and losses. Different β^*, number of bunches and intensities have been used in several dedicated experiments and allow the test of the expected scaling laws.

WEPFI015

Design and Field Measurements of a Linear Accelerator Endowed with Single Feed with Movable Short Coupler

linac, dipole, electron, simulation

2732

M. Dal Forno, R. Vescovo
University of Trieste, Trieste, Italy
P. Craievich, M. Dal Forno, G. Penco
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
P. Craievich
PSI, Villigen PSI, Switzerland

The free electron laser performances strongly depend on the beam quality. The dipolar field present in the linac coupler causes the beam emittance degradation. This paper studies an alternative solution for reducing the dipolar field, by using a symmetrical coupler with single feed input and a movable short circuit placed on the opposite waveguide. The structure has been simulated and optimized with the Ansys HFSS simulation code. An aluminum prototype has been machined in the workshop of “Elettra - Sincrotrone Trieste S.C.p.A.”. After matching and tuning the accelerating structure, the phase advance and the coupler field asymmetries have been measured by means of the bead-pull method and have been compared with the simulation results.

WEPFI045

PAL-XFEL Accelerating Structures

linac, klystron, electron, impedance

2806

H.-S. Lee, H. Heo, J.Y. Huang, W.H. Hwang, S.D. Jang, Y.D. Joo, H.-S. Kang, I.S. Ko, S.S. Park, Y.J. Park
PAL, Pohang, Kyungbuk, Republic of Korea
I.S. Ko
POSTECH, Pohang, Kyungbuk, Republic of Korea
H. Matsumoto
KEK, Ibaraki, Japan
S.J. Noh, K.M. Oh
Vitzrotech Co., Ltd., Ansan City, Kyunggi-Do, Republic of Korea

We need 172 accelerating structures for the PAL-XFEL 10 GeV main linac. It takes long time for these structures to be delivered. So we are trying to find suppliers of the accelerating structures. First, we made an order of 40 accelerating structures to Mitsubishi Heavy Industry (MHI), which have Quasi-type couplers to reduce the quadruple and sextuple components of the electric field in the coupling cavity. And Research Instruments (RI) has fabricated a 3m long race type accelerating structure for PAL-XFEL. Also, Vitzrotech which is a domestic company and IHEP in China are under developing accelerating structures for PAL-XFEL respectively. We will describe the current status of accelerating structures and high power test results of the newly developed structures in this paper.

WEPFI057

Longitudinal Design and RF Stability Requirements for the SwissFEL Facility

linac, wakefield, booster, undulator

2821

B. Beutner
PSI, Villigen PSI, Switzerland

The SwissFEL facility will produce coherent, bright, and short photon pulses covering a wavelength range down to an angstrom, requiring an emittance between 0.18 to 0.43 mm mrad at bunch charges between 10 pC and 200 pC. In nominal operation continuous changes in this range will be offered to the users to allow an individual tradeoff between photon power and pulse length. The facility consists of a S-band RF-gun, booster, and a C-band main linac, which accelerates the beam up to 5.8 GeV. Two compression chicanes will provide a nominal peak current of about 1 to 3 kA depending on the charge. The stability of RF systems is a key design issue for stable compression schemes at reliable user facilies. In this paper different operation modes are presented and discussed in terms of machine stability requirements.

WEPFI064

Prototype Refinement of the VELA Transverse Deflecting Cavity Design

cavity, simulation, target, vacuum

2842

P. Goudket, S.R. Buckley, L.S. Cowie, A.E. Wheelhouse
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
G. Burt
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom

The Versatile Linear Accelerator (VELA) at Daresbury Laboratory will deliver low energy (5/6 MeV) short bunches (~40 fs) to a number of industrial experimental stations and for scientific research. In order to measure the longitudinal profile of the bunch an S-band transverse deflecting cavity will be inserted into the beamline. A transverse kick of around 5 MV is required therefore a 9 cell design has been chosen. As part of the design iteration a three-cell prototype has been built. Frequency measurements have been performed on the prototype cavity as well as Coordinate Measuring Machine to confirm that the dimensions are to the required design tolerances. Subsequently, further modelling has been performed to improve and refine the design of the 9-cell cavity, to ensure that the frequency of the final design is within the tuning range of the water thermal control system and that the field flatness requirement can be obtained.

WEPFI077

LLNL X-band Test Station Status

gun, alignment, cathode, vacuum

2872

R.A. Marsh, F. Albert, G.G. Anderson, S.G. Anderson, C.P.J. Barty, E.T. Dayton, S.E. Fisher, D.J. Gibson, F.V. Hartemann, S.S.Q. Wu
LLNL, Livermore, California, USA

Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344
In support of Compton scattering gamma-ray source efforts at LLNL, a multi-bunch test station is being developed to investigate accelerator optimization for future upgrades. This test station will enable work to explore the science and technology paths required to boost the current mono-energetic gamma-ray technology a higher effective repetition rate, potentially increasing the average gamma-ray brightness by two orders of magnitude. The test station will consist of a 5.5 cell X-band rf photoinjector, single accelerator section, and beam diagnostics. Detailed design of the test station including is complete, and will be presented with modeling simulations and future upgrade paths. The current status of the installation will also be discussed with future commissioning plans.

WEPME001

SOLEIL Beam Stability Status

feedback, coupling, undulator, electron

2917

N. Hubert, L. Cassinari, J.-C. Denard, M. Labat, J.-F. Lamarre, A. Nadji, L.S. Nadolski, D. Pédeau, M.-A. Tordeux
SOLEIL, Gif-sur-Yvette, France

This paper reports recent work for improving SOLEIL electron beam stability. X-BPMs from four bending magnet beamline frontends have been inserted in the global orbit feedback loops during user operation. The corresponding source point stabilities have improved and results are reported. Some of the new beamlines request more stringent stability than the existing ones. Their requirements are not only tighter for beam orbit but also for beam size and divergence stability. For these reasons, SOLEIL has decided to define beam quality criteria for each sensitive beamline. Then it can predict ahead of commissioning how well the beamline will likely perform. A feedback on the vertical emittance, measured by a pinhole camera, has been introduced in order to reduce beam size and divergence variations due to magnetic configuration changes of a few insertion devices.

WEPME011

Beam Tests and Plans for the CERN PS Transverse Damper System

damping, injection, betatron, kicker

2947

A. Blas, S.S. Gilardoni, G. Sterbini
CERN, Geneva, Switzerland

The CERN Proton Synchrotron (CPS) has been running without any transverse damping equipment since 1998, thanks to the stabilizing effect of the linear coupling applied between horizontal and vertical planes. Lately, the demand for an active damper strongly emerged for two main reasons: to avoid restrictions as imposed on the betatron tune settings by the linear coupling and to cure instabilities appearing with high intensity beams, especially at the extraction energy. Late in 2012, two electronic prototype units, newly developed for the CPS one-turn-feedback, were programmed with a firmware designed to satisfy the transverse feedback (TFB) requirements in both planes. The main achievements were to automatically adapt the loop delay to the particles' time-of-flight variation within a nanosecond precision and to compensate the changing betatron phase advance between pick-up and kicker during the entire accelerating cycle. With the power equipment limited to the modest bandwidth of 23 MHz and 2 x 800 W per plane, encouraging results were obtained such as fast damping of injection oscillations caused by injection errors, reduction of beam losses along the cycle and damping of instabilities at all CPS energies.

WEPME018

Ytterbium Laser Development of DAW RF Gun for SuperKEKB

laser, gun, linac, extraction

2965

X. Zhou, T. Natsui, Y. Ogawa, M. Yoshida
KEK, Ibaraki, Japan

For obtaining higher luminosity in the SuperKEKB, the photocathode RF electron gun with strong electric focusing field for high-current, low-emittance beams will be employed in the injector linac. The electron beams with a charge of 5 nC and a normalized emittance of 10 μm are expected to be generated in the photocathode RF gun by using the laser source with a center wavelength of 260 nm and a pulse width of 30 ps. Furthermore, for reducing the emittance, the laser pulse width should be reshaped from Gaussian to rectangle structure. Therefore, Ytterbium (Yb)-doped laser system that provides broader bandwidth, higher amplify efficiency and higher output power is employed. The laser system starts with a large mode-area Yb-doped fiber-based amplifier system, which consists of a passively mode-locked femtosecond Yb-fiber oscillator and two steps Yb-fiber amplifier. To obtain the several 10mJ-class pulse energy, a Yb:YAG thin-disk regenerative solid-state amplifier is employed. Deep UV pulses for the photocathode are generated by using two frequency-doubling stages. High pulse energy and good stability would be expected.

WEPME020

Alignment Plan and Survey Results of the Equipment for J-PARC 3 GeV RCS

alignment, quadrupole, dipole, injection

2971

N. Tani, H. Hotchi, J. Kamiya, M. Kinsho, O. Takeda, M. Yamamoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

Misalignment of several millimeters of the magnets of J-PARC 3GeV RCS in both horizontal and vertical directions was caused by the Tohoku Region Pacific Coast Earthquake on March 11, 2011. As the result of orbit calculation showed that the beam loss was acceptable for beam operation at 300kW, beam operation with the current placement has been implemented. Realignment of the equipment will be carried out from August to December in 2013. Survey carried out in the summer of 2013 found out misalignment of ceramic vacuum ducts therefore their positioning is necessary. In this paper, these measurement result and latest alignment plan for J-PARC 3GeV RCS are reported.

WEPME044

Generation of Controlled Losses in Milisecond Timescale with Transverse Damper in LHC

beam-losses, simulation, proton, injection

3025

M. Sapinski, T. Baer, V. Chetvertkova, B. Dehning, W. Höfle, A. Priebe, R. Schmidt, D. Valuch
CERN, Geneva, Switzerland

A controlled way of generating of beam losses is required in order to investigate the quench limits of the superconducting magnets in the LHC. This is especially difficult to achieve for losses with millisecond duration. A series of experiments using the transverse damper system has proven that such a fast loss can be obtained even in the case of rigid 4 TeV beams. This paper describes the optimisation of beam parameters and transverse damper waveform required to mimic fast loss scenarios and reports on extensive tracking simulations undertaken to fully understand the time and spatial structure of these losses. The application of this method to the final quench tests is also presented.

THOAB102

A Pepper-pot Based Device for Diagnostics of the Single-shot Beam

ion, LabView, vacuum, diagnostics

3093

S.X. Peng, J. Chen, J.E. Chen, Z.Y. Guo, P.N. Lu, H.T. Ren, Z.H. Wang, Y. Xu, Z.X. Yuan, T. Zhang, J. Zhao
PKU, Beijing, People's Republic of China
A.L. Zhang
Graduate University, Chinese Academy of Sciences, Beijing, People's Republic of China
J. Zhao
State Key Laboratory of Nuclear Physics and Technology, Beijing, Haidian District, People's Republic of China

Generally the beam emittance can be measured by different Emittance Measurement Units (EMUs), such as the pepper-pot device, the slit-wire type facility and the Allison scanner. However, for a microsecond single-shot ion beam, the pepper-pot device is a suitable choice because of its cut-off single-shot technique without any time-consuming step. A pepper-pot based beam current & profile measurement device, which is a combination of Faraday cup technique and pepper-pot measurement facility, was developed at PKU. It consists of a main Faraday cup with a pepper-pot mask at its bottom, and a Faraday cup array locating 3 mm away from the pepper-pot mask. This device has been tested at the PKU LEBT test bench and the measurement results are consistent with the results acquired by the Allison scanner. By replacing the Faraday cup array with a fluorescent screen and a CCD camera, this device becomes a facility that not only has the ability to measure the total beam current and the beam profile, but also has the capability to measure the beam emittance for CW or pulsed ion beams. Details will be presented in this paper.

Slides THOAB102 [5.332 MB]

THOBB101

Transverse-to-longitudinal Emittance Exchange at the Fermilab Advanced Superconducting Test Accelerator

quadrupole, simulation, cavity, controls

3103

C.R. Prokop, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
B.E. Carlsten
LANL, Los Alamos, New Mexico, USA
M.D. Church, P. Piot
Fermilab, Batavia, USA

Funding: LANL LDRD program, project 20110067DR U.S. DoE under Contract No. DE-FG02-08ER41532 with Northern Illinois University and under Contract No. DE-AC02-07CH11359 the Fermi Research Alliance, LLC.
Earlier experiments at Fermilab’s A0 Photoinjector Laboratory demonstrated successful transverse-to-longitudinal emittance exchange (EEX) using a transverse-deflecting cavity (TDC) located between two identical doglegs. Such a design has the disadvantage of transversely displacing the beam. An interesting alternative is an EEX beamline designed out of a variable R56 bunch compressor chicane. In this paper, we present design and simulation testing for a chicane-based EEX for eventual implementation at Fermilab’s Advanced Superconducting Test Accelerator. We explore several advanced EEX concepts, including bunch current profile shaping, bunch compression, and dispersion-boosting to relax the requirements on TDC power and cooling.

Slides THOBB101 [2.582 MB]

THPEA002

The Accelerator Control System at ELSA

controls, diagnostics, electron, synchrotron

3149

D. Proft, F. Frommberger, W. Hillert
ELSA, Bonn, Germany

To fulfill the new requirements of the post-accelerator mode of the electron stretcher facility ELSA, a new computer control system was developed during the early 1990s. Providing capabilities to control and monitor the facility, it represents the top layer of a distributed control system composed of HP workstations, VME and field bus processors as well as linux based personal computer s. In addition to regular updates and improvements, the HP-UX operated part of the control system recently was ported to linux, so the outdated HP workstations could be replaced by a single linux PC. All reference values, for example the betatron tune or the extraction energy, can be specified using a window-based graphical user front end. They are directly computed to hardware compatible representations. Vice versa, measured beam parameters, e.g. the transversal beam emittance, are displayed for easy user access, allowing real time diagnostics. This abstraction layer allows for an intuitive approach to machine operation, requiring no detailed knowledge of the hardware implementation. In this contribution, the design principles and implementation at different layers of the control system are presented.

THPME047

Progress of the RFQ Accelerator for PXIE

rfq, simulation, beam-transport, ion

3618

D. Li, M.D. Hoff, A.R. Lambert, J.W. Staples, S.P. Virostek
LBNL, Berkeley, California, USA
T.H. Luo
UMiss, University, Mississippi, USA
S. Nagaitsev, G.V. Romanov, A.V. Shemyakin, R.P. Stanek, J. Steimel
Fermilab, Batavia, USA

Funding: This work is supported by the Office of Science, United States Department of Energy under DOE contract DE-AC02-05CH11231.
The proposed Project X Injector Experiment (PXIE) is currently under development at Fermilab. PXIE is an R&D test accelerator that will replicate the front-end portion of Project X. The PXIE accelerator complex consists of a H⁻ ion source(s), low-energy beam transport (LEBT), 162.5 MHz normal conducting CW Radio-Frequency-Quadrupole (RFQ) accelerator, medium-energy beam transport (MEBT), broad-band beam chopper(s) and two superconducting cryomodules. In this paper, we will review and present recent progress of the PXIE RFQ, which will include an overview of the RFQ beam dynamics design, RF structure design, detailed thermal and mechanical analyses, fabrication test results and fabrication plan and schedule.

THPWA021

Studies of Density Distribution and Emittance Measurement for High Current Electronic Beam

electron, gun, simulation, ion

3672

Q.C. Li, Z.-F. He, J.M. Huang, D.M. Li, Y.-T. Zhang, X.K. Zhu
SINAP, Shanghai, People's Republic of China

Beam density distribution and emittance are the important parameters of an accelerator. The accurate emittance measurement has an important reference significance for the design of accelerating tube, and provides a design basis for the aperture size of accelerating tube. This paper introduces a beam measurement method which uses multiwire, can rotate in the horizontal plane and adjust in the Z coordinate. The results of simulation show that this method can accurately measure the beam density distribution and emittance, and the accuracy can meet the requirements of applied accelerator.

THPWA041

Acceptance and Transmission Simulations of the FETS RFQ

rfq, simulation, space-charge, solenoid

3720

S. Jolly, R.T.P. D'Arcy
UCL, London, United Kingdom
A.P. Letchford
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
J.K. Pozimski
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
J.K. Pozimski
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom

A 4m-long, 324MHz four-vane RFQ, consisting of four coupled sections, has been designed for the Front End Test Stand (FETS) at RAL in the UK. A novel design method, integrating the CAD and electromagnetic design of the RFQ with beam dynamics simulations, was used to optimise the design of the RFQ. With the design of the RFQ fixed, the focus has been on optimising the transmission of the RFQ at 3 MeV and matching the output of the FETS Low Energy Beam Transport (LEBT) to the RFQ acceptance. Extensive simulations have been carried out using General Particle Tracer (GPT) to map out the acceptance of the FETS RFQ for a 65 keV H⁻ input beam. Particular attention has focussed on optimising the simulations to match the optimised output of the FETS Penning-type H⁻ ion source. Results are presented of the transverse phase space limits on the RFQ input acceptance in both the zero current and full space charge regimes.

THPWA042

Investigation of Space Charge Compensation at FETS

ion, space-charge, ion-source, rfq

3723

J.K. Pozimski, S.M.H. Alsari, P. Savage
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
D.C. Faircloth, A.P. Letchford
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

In order to contribute to the development of high power proton accelerators in the MW range, to prepare the way for an ISIS upgrade and to contribute to the UK design effort on neutrino factories, a front end test stand (FETS) is being constructed at the Rutherford Appleton Laboratory (RAL) in the UK. The aim of the FETS is to demonstrate the production of a 60 mA, 2 ms, 50 pps chopped beam at 3 MeV with sufficient beam quality. The ion source and LEBT are operational with the RFQ under manufacture. As a more detailed knowledge is of interest also for other projects like ESS and LINAC4 the FETS LEBT was updated to perform a detailed experimental analysis of space charge compensation utilizing a pulsed decompensation electrode together with a residual gas ion energy spectrometer and a fast emittance measurement device. In the FETS LEBT a high degree of space charge compensation (~90%) and a rise time of space charge compensation around ~ 50 μs could be concluded from measurements . In this paper the results of the experimental work will be presented together with discussion of the findings in respect to beam transport.

THPWO005

Commissioning of the Spiral2 Deuteron Injector

rfq, proton, space-charge, solenoid

3764

D. Uriot, O. Tuske
CEA/DSM/IRFU, France
J.-L. Biarrotte
IPN, Orsay, France

The SPIRAL-2 superconducting linac driver, which aims at delivering 5 mA, 40 MeV deuterons and up to 1 mA, 14.5 A.MeV q/A=1/3 heavy ions, has now entered its construction phase in GANIL (Caen, France). The linac is composed of two injectors feeding one single RFQ, followed by a superconducting section based on 88 MHz independently-phased quarter-wave cavities with room temperature focusing elements. The protons/deuteron injector have been fully built and commissioned at CEA Saclay in 2012, before moving and final installation at GANIL in 2013. Beam emittances have been measured at different positions of the LEBT and especially at the RFQ injection point. The space-charge beam compensation has been also carefully studied. This paper describes all the results obtained during this commissioning.

THPWO006

Beam Commissioning of the Linear IFMIF Prototype Accelerator Injector: Measurements and Simulations

solenoid, simulation, ion-source, ion

3767

N. Chauvin, S. Chel, O. Delferrière, R. Gobin, P.A.P. Nghiem, F. Senée, M. Valette
CEA/IRFU, Gif-sur-Yvette, France
A. Mosnier
Fusion for Energy, Garching, Germany
Y. Okumura
JAEA, Rokkasho, Japan
H. Shidara
IFMIF/EVEDA, Rokkasho, Japan
D. Uriot
CEA/DSM/IRFU, France

The EVEDA (Engineering Validation and Engineering Design Activities) phase of the IFMIF (International Fusion Materials Irradiation Facility) project consists in building, testing and operating, in Japan, a 125 mA/9 MeV deuteron accelerator, called LIPAc, which has been developed in Europe. The 140 mA cw D⁺ beam that has to be delivered by the LIPAc injector is produced by a 2.45 GHz ECR ion source based on the SILHI design. The low energy beam transfer line (LEBT) relies on a dual solenoid focusing system to transport the beam and to match it into the RFQ*. The beam line is equipped by several diagnostics: intensity measurement, emittance measurement unit, profilers and beam proportion analysis. During the LIPAc injector beam commissioning performed in CEA-Saclay, the deuteron beam intensity transported at the end of the LEBT reached an unprecedented value of 140 mA at 100 keV. In this paper, the results obtained during the commissioning are presented. In particular, beam emittance measurements as a function of duty cycle, extracted current from the ion source and solenoid tunings are exposed. The experimental results are discussed and compared to beam dynamics simulations.
* R. Gobin et al., this conference

THPWO021

Gabor Lens Performance Studies at the GSI High Current Test Injector

ion, electron, beam-transport, space-charge

3806

K. Schulte, M. Droba, O. Meusel, U. Ratzinger
IAP, Frankfurt am Main, Germany
A. Adonin, R. Berezov, R. Hollinger, J. Pfister
GSI, Darmstadt, Germany

At the Institute for Applied Physics (IAP) the application of Gabor space charge lenses as a focusing device for low energy ion beams has already been studied for several years. Inside Gabor lenses electrons are confined by external fields. In case of a homogeneously distributed electron cloud the resulting linear electric space charge field enables the focusing of high intensity heavy ion beams without aberrations. Therefore, the Gabor lens is a promising approach for mass-independent focusing and possible space charge compensation of ion beams. In mid-2012 the performance of a prototype lens has successfully been tested at the GSI High Current Test Injector (HOSTI). GSI and IAP are currently investigating the possible application of such a device for the continuous operation at the High Current Injector (HSI) for FAIR. This contribution will present the results of beam transport experiments at HOSTI as well as the determination of related plasma properties.

THPWO022

Beam Dynamics Design, Simulation and Benchmarking for the C-ADS Injector-II RFQ

rfq, simulation, linac, quadrupole

3809

C. Zhang
GSI, Darmstadt, Germany
C. Xiao
IAP, Frankfurt am Main, Germany

The planned Chinese Accelerator Driven System (C-ADS) will use two 10 MeV, up to 10 mA, and CW (Continuous Wave) proton linacs in parallel as injectors. Two versions of the injectors with different resonant frequencies as well as different cavity configurations are under development. This paper will focus on the beam dynamics design, simulation and benchmarking performed for the 162.5 MHz, 2.1 MeV Injector-II RFQ (Radio-Frequency Quadrupole).

THPWO023

The New RFQ as RIB Injector of the ALPI Linac

rfq, linac, injection, ion

3812

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

At the Legnaro National Laboratories it is operating a Super Conducting linac for nuclear studies named ALPI. A new project SPES is under study to provide neutron-rich rare nuclear beams (RIB) of final energies in the order of 10 MeV/A for nuclei in the A= 9-160 mass region. The radioactive ions will be produced with the ISOL technique using the proton induced fission on a Direct Target of UCx and subsequently reaccelerated using a new injector for the ALPI accelerator complex. In this paper the new RFQ injector and the transport line to ALPI will be describe.

THPWO024

PROGRESS ON DTL DESIGN FOR ESS

DTL, linac, multipole, simulation

3815

M. Comunian, F. Grespan, A. Pisent, C. Roncolato
INFN/LNL, Legnaro (PD), Italy
R. De Prisco
ESS, Lund, Sweden
P. Mereu
INFN-Torino, Torino, Italy

In the European Spallation Source (ESS) accelerator, the Drift Tube Linac (DTL) will accelerate a proton beam of 50 mA pulse peak current from 3 to ~80 MeV. In this paper the engineering design of DTL tanks with the beam dynamics errors studies and the RF design are shown.

THPWO027

Lattice and Error Studies for J-PARC Linac Upgrade to 50mA/400MeV

linac, simulation, lattice, focusing

3818

Y. Liu
KEK/JAEA, Ibaraki-Ken, Japan
M. Ikegami
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

Equi-partitioning (EP) setting is applied as base-line design for the J-PARC linac upgrade from present 15mA/181MeVto 50mA/400MeV H⁻ beam. We also studied the possibility of mitigating the intra-beam stripping (IBSt) with constant-envelop setting for the frequency jump from 324MHz to the 972MHz ACS section. Since the constant-envelop setting here for the frequency jump is away from equi-partitioning and close to the resonances kz=3kx, kz=2kx and so on, considerable emittance exchange and mismatch were found in the simulation. It is natural to continue the work to explore the parameter space around the above two typical settings. Three key points are to be checked. The first is the tradeoff between the envelopes big enough to suppress the IBSt and tunes not to be too depressed to the space charge region. The second point is the sensitivity of these lattices vs. errors. The third is about the criterion of mismatch in the presence of emittance exchange. When emittance exchange is serious the mismatch can be unavoidable. So it is crucial to ensure the settings are in the safe region free from un-controlled mismatch.

THPWO042

Macroparticle Simulation Studies of a Beam-core Matching Experiment

simulation, quadrupole, rfq, proton

3860

H. Jiang, P. Chen, S. Fu, T. Huang, F. Li, P. Li, H.C. Liu, C. Meng, M. Meng, Z.C. Mu, H.F. Ouyang, J. Peng, L.Y. Rong, B. Sun, J.M. Tian, B. Wang, S.C. Wang, W.Q. Xin, T.G. Xu, L. Zeng, F.X. Zhao
IHEP, Beijing, People's Republic of China

We compared the 3-D nonlinear macro- particle code IMPACT simulations with the measured beam-core profiles obtained by the wire-scanners in the beam-core matching experiment. Quadrupole scans were used to determinate the transverse properties of the RFQ output beam. The Gaussian distribution was chosen as the initial particle distribution, which is well fit with the measured beam-core profile. We matched the beam using the least-squares fitting procedure that adjusted the first four matching quadrupoles to produce equal rms beam size in the last six wire scanners. Simulations had been fairly successful in reproducing the core of the measured matched beam profiles.

THPWO044

Error Analysis and Beam Loss Control in C-ADS Main Linac

linac, simulation, cavity, solenoid

3866

C. Meng, Z. Li, J.Y. Tang, F. Yan
IHEP, Beijing, People's Republic of China

The China ADS (C-ADS) driver linac is defined to deliver a CW proton beam of 1.5 GeV in energy and 10 mA in current. To meet the extremely high reliability and availability, it is very important and imperative to perform detailed error analysis to simulate the real machine, where the errors always exist. The error studies are by very intense macro-particle simulations by both Trace-Win and TRACK codes with space charge effects included. Through error analysis the proper closed-orbit correction scheme and the maximum tolerable hardware and alignment errors can be found. This paper presents the method to optimize the apertures of elements in the C-ADS main linac. According to the detailed sensitivity analysis of different errors, the static and dynamic errors for the main linac are proposed. The basic lattice scheme has also been re-optimized based on the error studies. The correction scheme is also described, and with the correction scheme the residual orbit can be controlled very well. The influence of the correctors and BPM failures on the correction scheme is also studied.

THPWO045

Commissioning Plan for the CSNS Linac

DTL, linac, diagnostics, quadrupole

3869

J. Peng, S. Fu, J. Li, Y. Li, H.C. Liu, H.F. Ouyang, N. Wang, S. Wang, T.G. Xu
IHEP, Beijing, People's Republic of China

The linac of the China Spallation Neutron Source(CSNS) will be commissioned from October 2013. The linac will be commissioned in three phases. The delivery of beam to the RCS is planned for October 2015. This paper describes the commissioning plans for the MEBT and DTL parts of the linac. Techniques for finding the RF set-point, matching and steering are presented, as well as codes to assist in the beam commissioning.

THPWO056

A 5.3 MeV/U, 200MHz APF DTL for Carbon Ions as an Injector of Medical Synchrotron

synchrotron, focusing, cavity, DTL

3890

P. Jiang, Y.J. Yuan
IMP, Lanzhou, People's Republic of China

A new low energy medium frequency DTL for 12C⁵⁺ with alternative phase focusing method (APF), which has advantage in compact space and low cost, was designed as an injector of medical synchrotron. There is no conventional focusing elements in the APF DTL, and transversal focusing is realized using RF field by varying synchronous phase instead. The envelopes of beam size are presented and the emittance change of six-dimension phase space is shown. The simple method proposed by Y. Iwata was used to create synchronous phase array. Since the motion between transversal and longitudinal plains are coupled, the longitudinal acceptance of the DTL is not large.

THPWO059

Beam Dynamics Design of the Main Accelerating Section with KONUS in the CSR-LINAC Proposal

linac, DTL, rfq, heavy-ion

3895

X.H. Zhang, H. Du, J.W. Xia, X. Yin, Y.J. Yuan
IMP, Lanzhou, People's Republic of China

The CSR-LINAC as the injector of the Cooling Storage Ring (CSR) has been proposed in Heavy Ion Research Facility in Lanzhou (HIRFL). The injection linac mainly consists of two Linacs, the Radio Frequency Quadrupole linac (RFQ) and the Drift Tube Linac (DTL). The KONUS (Kombinierte Null Grad Struktur) concept has been introduced to the drift tube linac section. In this paper, the re-matching of the main accelerating section will be finished in the 3.7MeV/u scheme and the new beam dynamics design updating to 7MeV/u will be shown. Through the beam re-matching, the relative emittance growth has been suppressed greatly along the linac. The KONUS structure is also adopted in the beam dynamics design that update from 3.7MeV/u to 7MeV/u and the good beam quality and transmission is shown.

THPWO065

Optics Design and Correction of High Order Aberration of the Charge Stripper Beam Line of RAON

stripper, sextupole, ion, optics

3906

H.J. Kim, D. Jeon, H.J. Kim
IBS, Daejeon, Republic of Korea
J.G. Hwang, E.-S. Kim
Kyungpook National University, Daegu, Republic of Korea

RAON (Rare isotope Accelerator Of Newness) in Korea will be providing the 400 kW of 238U⁷⁹⁺ beam with 8 puA and 200 MeV/u. One of the critical components of this project in the SCL is the design of the charge stripper. Between the two segments of the SCL, the charge stripper strips electrons from ion beams to enhance the acceleration efficiency in the following SCL2. For high efficiency of the acceleration and high power in SCL2, the optimum energy of striped ion in solid carbon foil stripper for SCL1 was estimated by using code LISE. The thickness of the solid carbon foil is 300 ug/m2. Based on this study, the charge stripping efficiency of solid carbon stripper is ~80 %. For the charge selection from ions which produced by the solid carbon stripper, the dispersive section is required in down-stream of the foil. The designed optics for dispersive section is based on the mirror-symmetric optics to minimize the effect of high-order aberration. And the high-order aberration in designed optics was investigated and performed the correction of high-order effect using sextupole magnets.

THPWO072

Design Options of the ESS Linac

linac, target, cryomodule, proton

3921

M. Eshraqi, H. Danared, D.P. McGinnis
ESS, Lund, Sweden

The European Spallation Source, ESS, uses a linear accelerator to deliver the high intensity proton beam to the target station. The nominal average beam power is 5~MW with a peak beam power at target of 125~MW. During last year the ESS linac was costed, and to meet the budget a few modifications were introduced to the linac design, namely the final energy was decreased from 2.5~GeV to 2.0~GeV and the beam current was increased accordingly to compensate the lower final energy. As a result the linac is designed to meet the cost objective by taking a higher risk. This paper focuses on the new design options, beam dynamics requirements of the design and finally on the beam dynamics performance of the linac.

THPWO076

Design Study for 10 MHz Beam Frequency of Post-accelerated RIBs at HIE-ISOLDE

rfq, bunching, linac, solenoid

3933

M.A. Fraser, R. Calaga, I.-B. Magdau
CERN, Geneva, Switzerland

An increased bunch spacing of approximately 100 ns is requested by several research groups targeting experimental physics at HIE-ISOLDE. A design study testing the feasibility of retrofitting the existing 101.28 MHz REX (Radioactive ion beam EXperiment) RFQ with a sub-harmonic external pre-buncher at the ISOLDE radioactive nuclear beam facility has been carried out as a means of decreasing the beam frequency by a factor of 10. The proposed scheme for the 10 MHz bunch repetition frequency is presented and its performance assessed with beam dynamics simulations. The opportunity to reduce the longitudinal emittance formed in the RFQ is discussed along with the options for chopping the satellite bunches populated in the bunching process.

THPWO080

Operational Performance of the LHC Proton Beams with the SPS Low Transition Energy Optics

optics, brightness, extraction, injection

3945

Y. Papaphilippou, G. Arduini, T. Argyropoulos, W. Bartmann, H. Bartosik, T. Bohl, C. Bracco, S. Cettour-Cave, K. Cornelis, L.N. Drøsdal, J. Esteban Müller, B. Goddard, A. Guerrero, W. Höfle, V. Kain, G. Rumolo, B. Salvant, E.N. Shaposhnikova, H. Timko, D. Valuch, G. Vanbavinckhove, J. Wenninger
CERN, Geneva, Switzerland
E. Gianfelice-Wendt
Fermilab, Batavia, USA

An optics in the SPS with lower integer tunes (20 versus 26) was proposed and introduced in machine studies since 2010, as a measure for increasing transverse and longitudinal instability thresholds, especially at low energy, for the LHC proton beams. After two years of machine studies and careful optimisation, the new “Q20” optics became operational in September 2012 and steadily delivered beam to the LHC until the end of the run. This paper reviews the operational performance of the Q20 optics with respect to transverse and longitudinal beam characteristics in the SPS, enabling high brightness beams injected into the LHC. Aspects of longitudinal beam stability, transmission, high-energy orbit control and beam transfer are discussed.

THPWO081

Design Options of a High-power Proton Synchrotron for LAGUNA-LBNO

space-charge, dipole, proton, optics

3948

Y. Papaphilippou, J. Alabau-Gonzalvo, A. Alekou, F. Antoniou, M. Benedikt, I. Efthymiopoulos, R. Garoby, F. Gerigk, B. Goddard, C. Lazaridis, A.S. Parfenova, E.N. Shaposhnikova, R. Steerenberg
CERN, Geneva, Switzerland

Design studies have been initiated at CERN, exploring the prospects of future high-power proton beams for producing neutrinos, within the LAGUNA-LBNO project. These studies include the design of a 2 MW high-power proton synchrotron (HP-PS) using the LP-SPL as injector. This paper resumes the design options under study in order to reach this high power, and their implications regarding layout, magnet technology beam loss control and RF considerations. Optics optimization studies are also presented including beam transfer and collimation considerations.

THPWO082

Commissioning of the Linac4 RFQ at the 3 MeV Test Stand

rfq, linac, diagnostics, solenoid

3951

C. Rossi, L. Arnaudon, G. Bellodi, J.C. Broere, O. Brunner, A.M. Lombardi, J. Marques Balula, P. Martinez Yanez, J. Noirjean, C. Pasquino, U. Raich, F. Roncarolo, M. Vretenar
CERN, Geneva, Switzerland
M. Desmons, A. France, O. Piquet
CEA/IRFU, Gif-sur-Yvette, France

Linac4, the future 160MeV H⁻ injector to the CERN Proton Synchrotron Booster, is presently under construction at CERN as a first step of the planned upgrade of the LHC injectors. The low energy section of LINAC4, consisting of an ion source, a 352.2 MHz Radio Frequency Quadrupole (RFQ) and a chopper line is being commissioned in a dedicated test stand before installation in its final position in the tunnel. The RFQ is designed to accelerate a 45 keV, 70 mA, H⁻ beam to 3 MeV, with an efficiency of 95% while preserving the transverse emittance. The RFQ, a four-vane structure 3 m in length, has been designed in collaboration with CEA/IRFU and it has been built at the CERN workshop. The precise fabrication has allowed to achieve a field flatness of 1%. The completion of the accelerating structure in September 2012 was followed by a complete series of bead-pull measurements and by high-power conditioning to the nominal power of 0.39 MW corresponding to a voltage of 78 kV across the 3 meters. Measurements with beam are foreseen during the first half of 2013. This paper reports the results of the low-power and high power RF commissioning as well as the status of beam measurements.

THPWO087

Measurement of Resonant Space Charge Effects in the J-PARC Linac

linac, resonance, simulation, space-charge

3966

D.C. Plostinar
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
M. Ikegami
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
Y. Liu, T. Maruta
KEK/JAEA, Ibaraki-Ken, Japan

Traditionally, high intensity linac designs follow the “equipartitioning condition”, a strict control of the transverse and longitudinal tune ratios throughout the linac that ensures space-charge driven emittance exchange between the longitudinal and transverse planes is minimised. However, equipartitioning imposes strict rules on the linac design, thus limiting the design options and increasing the overall construction cost. More recently, practical tools have been developed that offer guidelines in designing non-equipartitioned linacs, by charting the stable regions in a tune ratio diagram (Hofmann’s Charts). While these stability diagrams have been backed by extensive multiparticle simulations and some experimental evidence, questions still remain regarding the practical consequences of crossing the resonances. In this paper preliminary results are presented from an experimental study conducted in the J-PARC linac, where for the first time we measured both the transverse and longitudinal emittance for different linac working points. A detailed analysis will be presented as well as a discussion on the wider implications of this experiment.

THPWO090

MEBT Design for the Front End Test Stand Project at RAL

quadrupole, cavity, lattice, diagnostics

3969

M. Aslaninejad, J.K. Pozimski, P. Savage
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

The Front End Test Stand (FETS) linear accelerator at Rutherford Appleton laboratory (RAL) will accelerate a 60 mA, 2 ms, 50 pps H⁻ beam up to 3 MeV. A new lattice design for the Medium Energy Beam Transport (MEBT) with a fast-slow chopping system is presented. Beam dynamic simulation has shown very good particle transmission in this new lattice with space charge effects included. The beam energy distribution on the beam choppers dumps is also calculated.

THPWO091

Staging Scenarios for Project-X

linac, lattice, rfq, acceleration

3972

N. Solyak, J.-P. Carneiro, V.A. Lebedev, S. Nagaitsev, J.-F. Ostiguy, A. Saini, A. Vivoli, V.P. Yakovlev
Fermilab, Batavia, USA

Funding: US DOE under contract DE-AC02-76CH03000.
Project-X is a high intensity proton source in development at Fermilab. At its heart is a linac based on superconducting technology comprising two distinct sections. The first one operates in CW mode and delivers beam with a flexible time structure to simultaneous experimental programs at 1 and 3 GeV. The second one operates in pulsed mode and accelerates a modest fraction (5%) of the beam from 3 GeV to 8 GeV for accumulation in the existing Main Injector complex. In an era of constrained budgets, construction in stages -with each stage capable of supporting worthy scientific programs - may be advantageous. Requirements for each program, coupled to the physical constraints imposed by the Fermilab site have led to a few possible scenarios, which are discussed in this contribution. In particular, we examine the implications of introducing bends in the linac at 1 and 3 GeV in terms of overall performance, flexibility and cost.

FRXAA01

Beam Dynamics and Collective Effects in "Ultimate" Storage Rings

ion, coupling, electron, scattering

3981

M. Takao
JASRI/SPring-8, Hyogo-ken, Japan

This presentation will review the beam dynamics issues such as impedance driven instabilities, intrabeam scattering, and the Touschek lifetime in ultimate storage rings with very low emittance.

Slides FRXAA01 [11.245 MB]