LINAC2012 - List of Keywords (acceleration)

Paper	Title	Other Keywords	Page
SUPB003	Feasibility Study of Short Pulse Mode Operation for Multi-turn ERL Light Source	linac, emittance, simulation, undulator	4
	T. Atkinson, A.V. Bondarenko, A.N. Matveenko, Y. Petenev HZB, Berlin, Germany
	The optics and simulation group at HZB are designing Germany’s future light source. Based on the emerging Energy Recovery Linac super conducting technology, the Femto-Science-Factory (FSF) will provide its users with ultra-bright photons of Angstrom wavelength at 6 GeV. The FSF is intended to be a multi-user facility and offer a wide variety of operation modes. A low emittance ~0.1 μm rad mode will operate in conjunction with a short-pulse ~10 fs mode. This paper highlights the physical limitations when trying to offer interchangeable modes and preserve beam high quality.

SUPB004	Linac Optics Design for Multi-turn ERL Light Source	linac, cavity, optics, cryomodule	7
	Y. Petenev, T. Atkinson, A.V. Bondarenko, A.N. Matveenko HZB, Berlin, Germany
	The optics simulation group at HZB is designing a multi-turn energy recovery linac-based light source. Using the superconducting Linac technology, the Femto-Science-Factory (FSF) will provide its users with ultra-bright photon beams of angstrom wavelength at 6 GeV. The FSF is intended to be a multi-user facility and offer a variety of operation modes. In this paper a design of transverse optic of the beam motion in the Linacs is presented. An important point in the optics design was minimization of the beta-functions in the linac at all beam passes to suppress beam break-up (BBU) instability.

SUPB008	Specifications of the Distributed Timing System for the CLIC Main Linac	luminosity, linac, monitoring, collider	16
	A. Gerbershagen, A. Andersson, D. Schulte CERN, Geneva, Switzerland P. Burrows JAI, Oxford, United Kingdom F.Ö. Ilday Bilkent University, Bilkent, Ankara, Turkey
	The longitudinal phase stability of CLIC main and drive beams is a crucial element of CLIC design. In order to measure and to control the phase, a distributed phase monitoring system has been proposed. The system measures the beam phase every 900 m. The relative phase between the measurement points is synchronized with an external reference system via a chain of reference lines. This paper presents the simulations of error propagation in the proposed distributed monitoring system and the impact on the drive and main beam phase errors and the luminosity. Based on the results the error tolerances for the proposed system are detailed.

SUPB010	Measurements of a Reduced Energy Spread of a Recirculating Linac by Non-Isochronous Beam Dynamics	recirculation, linac, electron, synchrotron	22
	F. Hug, C. Burandt, M. Konrad, N. Pietralla TU Darmstadt, Darmstadt, Germany R. Eichhorn Cornell University, Ithaca, New York, USA
	Funding: supported by DFG through SFB 634 The Superconducting Linear Accelerator S-DALINAC at the University of Darmstadt (Germany) is a recirculating linac with two recirculations providing beams for measurements in nuclear physics at small momentum transfers. For these experiments an energy spread of better than 10^-4 (rms) is needed. Currently acceleration in the linac section is done on crest of the accelerating field. The recirculation path is operated achromatic and isochronous. In this recirculation scheme the energy spread of the resulting beam in the ideal case is determined by the electron bunch length. Taking into account the stability of the RF system the energy spread increases drastically to more than 10^-3 (rms). We will present a new non-isochronous recirculation scheme which helps cancelling out these errors from the rf-control. This scheme uses longitudinal dispersion in the recirculation paths and an acceleration off-crest with a certain phase with respect to the maximum. We will present results of the commissioning of the new system including measurements of the longitudinal dispersion in the recirculation arcs as well as measurements of the resulting energy spread using an electron spectrometer.

SUPB016	RFQ With Improved Energy Gain	rfq, simulation, ion, emittance	41
	A. Kolomiets ITEP, Moscow, Russia A.S. Plastun MEPhI, Moscow, Russia
	RFQ structure is practically only one choice for using in front ends of ion linacs for acceleration up to energy about 3 MeV. This limit is due to its relatively low acceleration efficiency. However it isn’t intrinsic feature of RFQ principle. It is defined only by vane geometry of conventional RFQ structure with sinusoidal modulation of vanes. The paper presents results of analysis RFQ with modified vane geometries that allow to improve acceleration efficiency. RFQ with modified vanes was used for design second section of heavy ion injector of TWAC for acceleration of ions with Z/A = 0.33 up to 7 MeV/u.

MOPLB03	Advances in Beam Tests of Dielectric Based Accelerating Structures	wakefield, electron, laser, linac	144
	A. Kanareykin, S.P. Antipov, J.E. Butler, C.-J. Jing Euclid TechLabs, LLC, Solon, Ohio, USA W. Gai ANL, Argonne, USA V. Yakimenko BNL, Upton, Long Island, New York, USA
	Funding: US Department of Energy Diamond is being evaluated as a dielectric material for dielectric loaded accelerating structures. It has a very low microwave loss tangent, high thermal conductivity, and supports high RF breakdown fields. We report on progress in our recent beam tests of the diamond based accelerating structures of the Ka-band and THz frequency ranges. Wakefield breakdown test of a diamond-loaded accelerating structure has been carried out at the ANL/AWA accelerator. The high charge beam from the AWA linac (~70 nC, σ_z = 2.5 mm) was passed through a rectangular diamond loaded resonator and induce an intense wakefield. A groove is cut on the diamond to enhance the field. Electric fields up to 0.3 GV/m has been detected on the diamond surface to attempt to initiate breakdown. A surface analysis of the diamond has been performed before and after the beam test. Wakefield effects in a 250 GHz planar diamond accelerating structure has been observed at BNL/ATF accelerator as well. We have directly measured the mm-wave wake fields induced by subpicosecond, intense relativistic electron bunches in a diamond loaded accelerating structure via the dielectric wake-field acceleration mechanism.
	Slides MOPLB03 [1.986 MB]

MOPLB11	The Upgraded Argonne Wakefield Accelerator Facility (AWA): a Test-Bed for the Development of High Gradient Accelerating Structures and Wakefield Measurements	wakefield, electron, gun, linac	168
	M.E. Conde, D.S. Doran, W. Gai, R. Konecny, W. Liu, J.G. Power, Z.M. Yusof ANL, Argonne, USA S.P. Antipov, C.-J. Jing Euclid TechLabs, LLC, Solon, Ohio, USA E.E. Wisniewski Illinois Institute of Technology, Chicago, Illinois, USA
	Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC02-06CH11357. Electron beam driven wakefield acceleration is a bona fide path to reach high gradient acceleration of electrons and positrons. With the goal of demonstrating the feasibility of this concept with realistic parameters, well beyond a proof-of-principle scenario, the AWA Facility is currently undergoing a major upgrade that will enable it to achieve accelerating gradients of hundreds of MV/m and energy gains on the order of 100 MeV per structure. A key aspect of the studies and experiments carried out at the AWA facility is the use of relatively short RF pulses (15 – 25 ns), which is believed to mitigate the risk of breakdown and structure damage. The upgraded facility will utilize long trains of high charge electron bunches to drive wakefields in the microwave range of frequencies (8 to 26 GHz), generating RF pulses with GW power levels.
	Slides MOPLB11 [0.900 MB]

MOPB005	High Gradient Operation of 8 GeV C-Band Accelerator in SACLA	laser, electron, klystron, free-electron-laser	186
	T. Inagaki, C. Kondo, Y. Otake, T. Sakurai RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
	SACLA (SPring-8 angstrom compact free electron laser) is the X-ray free electron laser (XFEL) facility. In order to shorten the 8 GeV accelerator length, a C-band (5712 MHz) accelerator was employed. Since the accelerating gradient of C-band accelerating structure is 35 MV/m in nominal, the active accelerator length is 230 m. In total, 64 klystrons, 64 pulse compressors, and 128 accelerating structures are used. In order to withstand the high surface field (~ 100 MV/m), and to reduce the amount of dark current, which decreases the demagnetization effect of undulators, the accelerating structures are carefully fabricated in the factory.　After high power RF conditioning of 500 hours, the beam commissioning was started in February 2011. For night time of the commissioning, we continued the RF conditioning. The RF breakdown rate of the structure was steadily decreased. Now we operate the accelerator with the beam energy as much as 8.3 GeV, and the accelerating gradient of 37 MV/m in average. We found the amount of dark current is small enough. So far no trouble occurred in C-band RF components of 64 sets.

MOPB036	Feasibility Study of Short Pulse Mode Operation for Multi-turn ERL Light Source	linac, emittance, simulation, undulator	255
	T. Atkinson, A.V. Bondarenko, A.N. Matveenko, Y. Petenev HZB, Berlin, Germany
	The optics and simulation group at HZB are designing Germany’s future light source. Based on the emerging Energy Recovery Linac super conducting technology, the Femto-Science-Factory (FSF) will provide its users with ultra-bright photons of Angstrom wavelength at 6 GeV. The FSF is intended to be a multi-user facility and offer a wide variety of operation modes. A low emittance ~0.1 μm rad mode will operate in conjunction with a short-pulse ~10 fs mode. This paper highlights the physical limitations when trying to offer interchangeable modes and preserve beam high quality.

MOPB037	Linac Optics Design for Multi-turn ERL Light Source	linac, cavity, optics, cryomodule	258
	Y. Petenev, T. Atkinson, A.V. Bondarenko, A.N. Matveenko HZB, Berlin, Germany
	The optics simulation group at HZB is designing a multi-turn energy recovery linac-based light source. Using the superconducting Linac technology, the Femto-Science-Factory (FSF) will provide its users with ultra-bright photon beams of angstrom wavelength at 6 GeV. The FSF is intended to be a multi-user facility and offer a variety of operation modes. In this paper a design of transverse optic of the beam motion in the Linacs is presented. An important point in the optics design was minimization of the beta-functions in the linac at all beam passes to suppress beam break-up (BBU) instability.

MOPB041	Advances in Beam Tests of Dielectric Based Accelerating Structures	wakefield, electron, laser, linac	264
	A. Kanareykin, S.P. Antipov, J.E. Butler, C.-J. Jing Euclid TechLabs, LLC, Solon, Ohio, USA W. Gai ANL, Argonne, USA V. Yakimenko BNL, Upton, Long Island, New York, USA
	Funding: US Department of Energy Diamond is being evaluated as a dielectric material for dielectric loaded accelerating structures. It has a very low microwave loss tangent, high thermal conductivity, and supports high RF breakdown fields. We report on progress in our recent beam tests of the diamond based accelerating structures of the Ka-band and THz frequency ranges. Wakefield breakdown test of a diamond-loaded accelerating structure has been carried out at the ANL/AWA accelerator. The high charge beam from the AWA linac (~70 nC, σ_z = 2.5 mm) was passed through a rectangular diamond loaded resonator and induce an intense wakefield. A groove is cut on the diamond to enhance the field. Electric fields up to 0.3 GV/m has been detected on the diamond surface to attempt to initiate breakdown. A surface analysis of the diamond has been performed before and after the beam test. Wakefield effects in a 250 GHz planar diamond accelerating structure has been observed at BNL/ATF accelerator as well. We have directly measured the mm-wave wake fields induced by subpicosecond, intense relativistic electron bunches in a diamond loaded accelerating structure via the dielectric wake-field acceleration mechanism.

MOPB045	Specifications of the Distributed Timing System for the CLIC Main Linac	luminosity, linac, monitoring, collider	273
	A. Gerbershagen, A. Andersson, D. Schulte CERN, Geneva, Switzerland P. Burrows JAI, Oxford, United Kingdom F.Ö. Ilday Bilkent University, Bilkent, Ankara, Turkey
	The longitudinal phase stability of CLIC main and drive beams is a crucial element of CLIC design. In order to measure and to control the phase, a distributed phase monitoring system has been proposed. The system measures the beam phase every 900 m. The relative phase between the measurement points is synchronized with an external reference system via a chain of reference lines. This paper presents the simulations of error propagation in the proposed distributed monitoring system and the impact on the drive and main beam phase errors and the luminosity. Based on the results the error tolerances for the proposed system are detailed.

MOPB062	A New Internal Optical Profilometry System for Characterization of RF Cavity Surfaces – CYCLOPS	cavity, controls, ion, feedback	318
	C.E. Reece, A.D. Palczewski, H. Tian JLAB, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Jefferson Lab has received and commissioned a new interferometric optical profilometer specifically designed to provide internal surface mapping of elliptical rf cavities. The CavitY CaLibrated Optical Profilometry System – CYCLOPS – provides better than 2 micron lateral resolution and 0.1 micron surface height resolution of programmatically selected locations on the interior surface of multi-cell cavities. The system is being used to provide detailed characterization of surface topographic evolution as a function of applied surface treatments and to investigate particular localized defects. We also intend to use the system for 3D mapping of actual interior rf surface geometry for feedback to structure design model and fabrication tooling. First uses will be illustrated. CYCLOPS was developed and fabricated by MicroDynamics Inc., Woodstock, GA, USA.

MOPB066	Alternative Approaches for HOM-Damped Cavities	multipole, cavity, HOM, linac	330
	B. Riemann, T. Weis DELTA, Dortmund, Germany A. Neumann HZB, Berlin, Germany
	Funding: this work is partly funded by BMBF contract no. 05K10PEA Elliptical cavities have been a standard in SRF linac technology for 30 years. We present another approach to base cell geometry based on Bezier splines, that leads to equal performance levels and is much more flexible in terms of optimization. Using the BERLinPro main linac as an example, a spline multicell cavity is designed with equal performance goals. For the damping of higher order modes (HOMs), the installation of waveguides at the ends of a multicell cavity is a common approach.

MOPB070	Quality Control of Cleanroom Processing Procedures of SRF Cavities for Mass Production	cavity, controls, SRF, diagnostics	339
	R. Oweiss, K. Elliott, A. Facco, M. Hodek, I.M. Malloch, J. Popielarski, L. Popielarski, K. Saito FRIB, East Lansing, Michigan, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661. Quality control is a key factor in the success of SRF cavity mass production. This paper summarizes ongoing research at the Facility for Rare Isotope Beams FRIB to validate the quality assurance of SRF cavities meanwhile optimizing processing procedures for mass production. Experiments are conducted to correlate surface cleanliness for niobium surfaces with high pressure rinse time using β=0.085 quarter-wave resonators (QWR) cavities. Diagnostic devices; liquid particle counter, surface particle detector and TOC analyzer are used to monitor key parameters for quality control. Rinse water samples are collected during high pressure rinsing to measure liquid particle counts. The SLS 1200 Sampler is used to detect the presence of liquid particles of 0.2 microns and up to 1 micron to set standards for acceptable cleaning thresholds and optimize high pressure rinse time. The QIII+ surface particle detector is used to scan high electric field region for the β=0.085 QWR to ensure high pressure rinsing efficiency. The β=0.085 QWR RF testing data are analyzed and results are presented to demonstrate the correlation between attained acceleration gradients and surface cleanliness.

MOPB081	Travelling Wave Accelerating Structures with a Large Phase Advance	electron, linac, impedance, proton	363
	V.V. Paramonov RAS/INR, Moscow, Russia
	The electrons acceleration is considered in higher pass bands of TM01 wave for disk loaded waveguide, resulting in the possibility of traveling wave accelerating structures with an operating field phase advance between 180 – 1260 degrees per cell. With an appropriate shape optimization and some additional elements in cells proposed traveling wave structures have small transverse dimensions and high RF efficiency of standing wave operation. Examples of proposed structures together with RF and dispersion properties are presented.

MOPB093	The Upgraded Argonne Wakefield Accelerator Facility (AWA): a Test-Bed for the Development of High Gradient Accelerating Structures and Wakefield Measurements	wakefield, electron, gun, linac	392
	M.E. Conde, D.S. Doran, W. Gai, R. Konecny, W. Liu, J.G. Power, Z.M. Yusof ANL, Argonne, USA S.P. Antipov, C.-J. Jing Euclid TechLabs, LLC, Solon, Ohio, USA E.E. Wisniewski Illinois Institute of Technology, Chicago, Illinois, USA
	Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC02-06CH11357. Electron beam driven wakefield acceleration is a bona fide path to reach high gradient acceleration of electrons and positrons. With the goal of demonstrating the feasibility of this concept with realistic parameters, well beyond a proof-of-principle scenario, the AWA Facility is currently undergoing a major upgrade that will enable it to achieve accelerating gradients of hundreds of MV/m and energy gains on the order of 100 MeV per structure. A key aspect of the studies and experiments carried out at the AWA facility is the use of relatively short RF pulses (15 – 25 ns), which is believed to mitigate the risk of breakdown and structure damage. The upgraded facility will utilize long trains of high charge electron bunches to drive wakefields in the microwave range of frequencies (8 to 26 GHz), generating RF pulses with GW power levels.

TUPLB08	R&D Towards CW Ion Linacs at ANL	cryomodule, rfq, cavity, ion	461
	P.N. Ostroumov, A. Barcikowski, Z.A. Conway, S.M. Gerbick, M. Kedzie, M.P. Kelly, S.V. Kutsaev, J.W. Morgan, R.C. Murphy, B. Mustapha, D.R. Paskvan, T. Reid, D.L. Schrage, S.I. Sharamentov, K.W. Shepard, G.P. Zinkann ANL, Argonne, USA
	Funding: This work was supported by the U.S. Department of Energy, Office of High Energy Physics and Nuclear Physics, under Contract DE-AC02-76CH03000, DE-AC02-06CH11357 and ANL WFO 85Y47. The accelerator development group in ANL’s Physics Division has engaged in substantial R&D related to CW proton and ion accelerators. Particularly, a 4 meter long 60.625 MHz CW RFQ has been developed, built and is being commissioned with beam. Development and fabrication of a cryomodule with seven 72.75 MHz quarter-wave cavities is complete and it is being assembled. Off-line testing of several QWRs has demonstrated outstanding performance in terms of both accelerating voltage and surface resistance. Both the RFQ and cryomodule were developed and built to upgrade ATLAS to higher efficiency and beam intensities. Another cryomodule with eight 162.5 MHz SC HWRs and eight SC solenoids is being developed and built for Project X at FNAL. We are also developing both an RFQ and cryomodules (housing 176 MHz HWRs) for proton & deuteron acceleration at SNRC (Soreq, Israel). In this paper we discuss ANL-developed technologies for normal-conducting and SC accelerating structures for medium- and high-power CW accelerators, including the projects mentioned above and other developments for applications such as transmutation of spent reactor fuel.
	Slides TUPLB08 [1.414 MB]

TUPB026	Measurements of a Reduced Energy Spread of a Recirculating Linac by Non-isochronous Beam Dynamics	recirculation, linac, electron, synchrotron	531
	F. Hug, C. Burandt, M. Konrad, N. Pietralla TU Darmstadt, Darmstadt, Germany R. Eichhorn Cornell University, Ithaca, New York, USA
	Funding: supported by DFG through SFB 634 The Superconducting Linear Accelerator S-DALINAC at the University of Darmstadt (Germany) is a recirculating linac with two recirculations providing beams for measurements in nuclear physics at small momentum transfers. For these experiments an energy spread of better than 10^-4 (rms) is needed. Currently acceleration in the linac section is done on crest of the accelerating field. The recirculation path is operated achromatic and isochronous. In this recirculation scheme the energy spread of the resulting beam in the ideal case is determined by the electron bunch length. Taking into account the stability of the RF system the energy spread increases drastically to more than 10^-3 (rms). We will present a new non-isochronous recirculation scheme which helps cancelling out these errors from the rf-control. This scheme uses longitudinal dispersion in the recirculation paths and an acceleration off-crest with a certain phase with respect to the maximum. We will present results of the commissioning of the new system including measurements of the longitudinal dispersion in the recirculation arcs as well as measurements of the resulting energy spread using an electron spectrometer.

TUPB043	One Design of Heavy Ion Linac Injector for CSRm	linac, ion, heavy-ion, emittance	573
	X.H. Zhang, J.W. Xia, Y.J. Yuan IMP, Lanzhou, People's Republic of China
	The design of heavy ion linac as one new injector of the main Cooling Storage Ring (CSRm) has been discussed. The linac design is based on interdigital H mode drift tube with KONUS (Kombinierte Null Grad Struktur). A high acceleration rate with zero degree synchronous particle phase acceleration reduce the length of IH-KONUS linac and the cost in comparison with conventional linac based on Alvarez structure. To reduce the effect of emittance growth, the RFQ structure is used in front of the IH-KONUS linac. In this linac, the design particle 238U²⁸⁺ will be accelerated to 7 AMeV, and the transmission of Uranium beam can reach up to 80%. In this report, the initial physics design of the main linac is presented.

TUPB046	R&D Towards CW Ion Linacs at ANL	cryomodule, rfq, cavity, ion	579
	P.N. Ostroumov, A. Barcikowski, Z.A. Conway, S.M. Gerbick, M. Kedzie, M.P. Kelly, S.V. Kutsaev, J.W. Morgan, R.C. Murphy, B. Mustapha, D.R. Paskvan, T. Reid, D.L. Schrage, S.I. Sharamentov, K.W. Shepard, G.P. Zinkann ANL, Argonne, USA
	Funding: This work was supported by the U.S. Department of Energy, Office of High Energy Physics and Nuclear Physics, under Contract DE-AC02-76CH03000, DE-AC02-06CH11357 and ANL WFO 85Y47. The accelerator development group in ANL’s Physics Division has engaged in substantial R&D related to CW proton and ion accelerators. Particularly, a 4 meter long 60.625 MHz CW RFQ has been developed, built and is being commissioned with beam. Development and fabrication of a cryomodule with seven 72.75 MHz quarter-wave cavities is complete and it is being assembled. Off-line testing of several QWRs has demonstrated outstanding performance in terms of both accelerating voltage and surface resistance. Both the RFQ and cryomodule were developed and built to upgrade ATLAS to higher efficiency and beam intensities. Another cryomodule with eight 162.5 MHz SC HWRs and eight SC solenoids is being developed and built for Project X at FNAL. We are also developing both an RFQ and cryomodules (housing 176 MHz HWRs) for proton & deuteron acceleration at SNRC (Soreq, Israel). In this paper we discuss ANL-developed technologies for normal-conducting and SC accelerating structures for medium- and high-power CW accelerators, including the projects mentioned above and other developments for applications such as transmutation of spent reactor fuel.

TUPB070	Development of Proton Therapy at the SC Linac with BEAMDULAC-SCL Code	linac, focusing, solenoid, proton	633
	A.V. Samoshin, S.M. Polozov MEPhI, Moscow, Russia
	Proton cancer therapy complexes are conventionally developing based on synchrotrons and cyclotrons. High electrical power consumption and especial devices necessary to energy variation (as slow extraction systems and degraders) are the main problems of such complexes. At once SC linacs based on short independently phased quarter and half wave cavities have a serious progress at present. Linear accelerator consumes less power comparably with cyclic and the energy variation can be easily realized by means of RF field amplitude and phase variation in a number of cavities. The accelerator’s modular configuration which is now widely used in FRIBs * or SNSs can be applied for therapy linac also (see for example *). It is possible to choose the SC linac parameters and proton and ion beams stability study with help of the BEAMDULAC-SCL code. This software also allows providing of the structure optimization and the beam dynamics control. P.N. Ostroumov and et al., Proc. of PAC2001, p.4080. ** C.Ronsivalle et al. Proc. of IPAC 2011, p. 3580.

TUPB102	Design and Performances of Phase Monitor in J-PARC Linac	linac, pick-up, vacuum, impedance	699
	A. Miura JAEA/J-PARC, Tokai-mura, Japan Z. Igarashi, T. Miyao KEK, Ibaraki, Japan
	J-PARC linac employs a fast current transformer (FCT) as a beam phase monitor to calculate the beam energy by time-of-flight method. We have installed and used 61 FCTs in the current beam line. Because the phase measurements at additional 41 points in the future ACS sections are required for the energy upgrade project with adding 21 ACS (Annular Coupled Structure) cavities, we stared the design and fabrication of FCTs as the phase measurement devices. In addition, J-PARC linac employs the 4-stripline beam position monitors (BPMs) for the beam position measurement. It has been considered that the signals from striplines of BPM would be useful for a phase measurement. A phase measurement using a BPM has been successfully conducted. In order to evaluate the performances of the FCT, the signal sensitivity and cut-off frequency of newly fabricated FCT are measured. Also, these data of the BPM are also measured to be compared with the data of FCT. Based on the results of the comparing both measurements, the superiority of both monitors for beam phase measurement is discussed.

WE2A01	RF Power Production at the Two Beam Test Stand at CERN	damping, recirculation, target, extraction	738
	I. Syratchev CERN, Geneva, Switzerland
	The generation of short (250 ns) high peak power (135 MW) RF pulses by decelerating the high current (100 A) bunched (12 GHz) drive beam is one of the key components in the CLIC two beam acceleration scheme. Recent tests with drive beam deceleration at CERN's CTF3, using specially developed 1 m long CLIC Power Extraction and Transfer Structure (PETS) operated in re-circulation regime have successfully demonstrated this concept. The results of these tests are presented.
	Slides WE2A01 [2.636 MB]

TH3A04	Plasmas, Dielectrics and the Ultrafast: First Science and Operational Experience at FACET	plasma, electron, radiation, linac	802
	C.I. Clarke, E. Adli, S. Corde, F.-J. Decker, R.J. England, R.A. Erickson, A.S. Fisher, S.J. Gessner, C. Hast, M.J. Hogan, S.Z. Li, N. Lipkowitz, M.D. Litos, Y. Nosochkov, J.T. Seeman, J. Sheppard, I. Tudosa, G.R. White, U. Wienands, M. Woodley, Z. Wu, G. Yocky SLAC, Menlo Park, California, USA C.E. Clayton, C. Joshi, W. Lu, K.A. Marsh, N. Vafaei UCLA, Los Angeles, California, USA
	Funding: Work supported by the U.S. Department of Energy under contract number DE-AC02-76SF00515. FACET (Facility for Advanced Accelerator and Experimental Tests) is an accelerator R&D test facility that has been recently constructed at SLAC National Accelerator Laboratory. The facility provides 20 GeV, 3 nC electron beams, short (20 um) bunches and small (20 um wide) spot sizes, producing uniquely high power beams. FACET supports studies from many fields but in particular those of Plasma Wakefield Acceleration and Dielectric Wakefield Acceleration. FACET is also a source of THz radiation for material studies. We present the FACET design, initial operating experience and first science from the facility.
	Slides TH3A04 [3.091 MB]

THPB050	RFQ With Improved Energy Gain	rfq, simulation, ion, emittance	966
	A. Kolomiets ITEP, Moscow, Russia A.S. Plastun MEPhI, Moscow, Russia
	RFQ structure is practically only one choice for using in front ends of ion linacs for acceleration up to energy about 3 MeV. This limit is due to its relatively low acceleration efficiency. However it isn’t intrinsic feature of RFQ principle. It is defined only by vane geometry of conventional RFQ structure with sinusoidal modulation of vanes. The paper presents results of analysis RFQ with modified vane geometries that allow to improve acceleration efficiency. RFQ with modified vanes was used for design second section of heavy ion injector of TWAC for acceleration of ions with Z/A = 0.33 up to 7 MeV/u.

THPB095	Designing of a Phase-mask-type Laser Driven Dielectric Accelerator for Radiobiology	laser, electron, simulation, vacuum	1041
	K. Koyama UTNL, Ibaraki, Japan A. Aimidura, M. Uesaka The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan Y. Matsumura University of Tokyo, Tokyo, Japan T. Natsui, M. Yoshida KEK, Ibaraki, Japan
	Funding: This work is supported by KAKENHI, Grant-in-Aid for Scientific Research (C) 24510120 In order to estimate the health risk of a low radiation dose, basic processes of the radiobiology should be clarified by shooting a DNA using a spatially and temporary defined particle beam or X-ray. A suitable beam size is as small as a resolving power of an optical microscope of a few hundred nanometers. Photonic crystal accelerators (PCA) are capable of delivering nm-beams of sub-fs pulses because the characteristic length and frequency of PCAs are on the order of the laser light. Since the phase-mask type accelerator has a simpler structure than other types of PCAs, we are designing a phase-mask type laser driven dielectric accelerator. By adopting an unbalanced length of pillar and ditch (grating) of 4:1, a standing wave like acceleration field is produced in a acceleration channel. A pillar height and initial speed of injected electron are determined by analytically. The maximum acceleration gradient of 2 GeV/m is estimated. The required laser power is roughly estimated to be 6.5 GW. The simulation using CST-code also shows similar values to accelerate electrons by the phase-mask type accelerator.

Paper

Title

Other Keywords

Page

SUPB003

Feasibility Study of Short Pulse Mode Operation for Multi-turn ERL Light Source

linac, emittance, simulation, undulator

4

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

The optics and simulation group at HZB are designing Germany’s future light source. Based on the emerging Energy Recovery Linac super conducting technology, the Femto-Science-Factory (FSF) will provide its users with ultra-bright photons of Angstrom wavelength at 6 GeV. The FSF is intended to be a multi-user facility and offer a wide variety of operation modes. A low emittance ~0.1 μm rad mode will operate in conjunction with a short-pulse ~10 fs mode. This paper highlights the physical limitations when trying to offer interchangeable modes and preserve beam high quality.

SUPB004

Linac Optics Design for Multi-turn ERL Light Source

linac, cavity, optics, cryomodule

7

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

The optics simulation group at HZB is designing a multi-turn energy recovery linac-based light source. Using the superconducting Linac technology, the Femto-Science-Factory (FSF) will provide its users with ultra-bright photon beams of angstrom wavelength at 6 GeV. The FSF is intended to be a multi-user facility and offer a variety of operation modes. In this paper a design of transverse optic of the beam motion in the Linacs is presented. An important point in the optics design was minimization of the beta-functions in the linac at all beam passes to suppress beam break-up (BBU) instability.

SUPB008

Specifications of the Distributed Timing System for the CLIC Main Linac

luminosity, linac, monitoring, collider

16

A. Gerbershagen, A. Andersson, D. Schulte
CERN, Geneva, Switzerland
P. Burrows
JAI, Oxford, United Kingdom
F.Ö. Ilday
Bilkent University, Bilkent, Ankara, Turkey

The longitudinal phase stability of CLIC main and drive beams is a crucial element of CLIC design. In order to measure and to control the phase, a distributed phase monitoring system has been proposed. The system measures the beam phase every 900 m. The relative phase between the measurement points is synchronized with an external reference system via a chain of reference lines. This paper presents the simulations of error propagation in the proposed distributed monitoring system and the impact on the drive and main beam phase errors and the luminosity. Based on the results the error tolerances for the proposed system are detailed.

SUPB010

Measurements of a Reduced Energy Spread of a Recirculating Linac by Non-Isochronous Beam Dynamics

recirculation, linac, electron, synchrotron

22

F. Hug, C. Burandt, M. Konrad, N. Pietralla
TU Darmstadt, Darmstadt, Germany
R. Eichhorn
Cornell University, Ithaca, New York, USA

Funding: supported by DFG through SFB 634
The Superconducting Linear Accelerator S-DALINAC at the University of Darmstadt (Germany) is a recirculating linac with two recirculations providing beams for measurements in nuclear physics at small momentum transfers. For these experiments an energy spread of better than 10^-4 (rms) is needed. Currently acceleration in the linac section is done on crest of the accelerating field. The recirculation path is operated achromatic and isochronous. In this recirculation scheme the energy spread of the resulting beam in the ideal case is determined by the electron bunch length. Taking into account the stability of the RF system the energy spread increases drastically to more than 10^-3 (rms). We will present a new non-isochronous recirculation scheme which helps cancelling out these errors from the rf-control. This scheme uses longitudinal dispersion in the recirculation paths and an acceleration off-crest with a certain phase with respect to the maximum. We will present results of the commissioning of the new system including measurements of the longitudinal dispersion in the recirculation arcs as well as measurements of the resulting energy spread using an electron spectrometer.

SUPB016

RFQ With Improved Energy Gain

rfq, simulation, ion, emittance

41

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

RFQ structure is practically only one choice for using in front ends of ion linacs for acceleration up to energy about 3 MeV. This limit is due to its relatively low acceleration efficiency. However it isn’t intrinsic feature of RFQ principle. It is defined only by vane geometry of conventional RFQ structure with sinusoidal modulation of vanes. The paper presents results of analysis RFQ with modified vane geometries that allow to improve acceleration efficiency. RFQ with modified vanes was used for design second section of heavy ion injector of TWAC for acceleration of ions with Z/A = 0.33 up to 7 MeV/u.

MOPLB03

Advances in Beam Tests of Dielectric Based Accelerating Structures

wakefield, electron, laser, linac

144

A. Kanareykin, S.P. Antipov, J.E. Butler, C.-J. Jing
Euclid TechLabs, LLC, Solon, Ohio, USA
W. Gai
ANL, Argonne, USA
V. Yakimenko
BNL, Upton, Long Island, New York, USA

Funding: US Department of Energy
Diamond is being evaluated as a dielectric material for dielectric loaded accelerating structures. It has a very low microwave loss tangent, high thermal conductivity, and supports high RF breakdown fields. We report on progress in our recent beam tests of the diamond based accelerating structures of the Ka-band and THz frequency ranges. Wakefield breakdown test of a diamond-loaded accelerating structure has been carried out at the ANL/AWA accelerator. The high charge beam from the AWA linac (~70 nC, σ_z = 2.5 mm) was passed through a rectangular diamond loaded resonator and induce an intense wakefield. A groove is cut on the diamond to enhance the field. Electric fields up to 0.3 GV/m has been detected on the diamond surface to attempt to initiate breakdown. A surface analysis of the diamond has been performed before and after the beam test. Wakefield effects in a 250 GHz planar diamond accelerating structure has been observed at BNL/ATF accelerator as well. We have directly measured the mm-wave wake fields induced by subpicosecond, intense relativistic electron bunches in a diamond loaded accelerating structure via the dielectric wake-field acceleration mechanism.

Slides MOPLB03 [1.986 MB]

MOPLB11

The Upgraded Argonne Wakefield Accelerator Facility (AWA): a Test-Bed for the Development of High Gradient Accelerating Structures and Wakefield Measurements

wakefield, electron, gun, linac

168

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

Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC02-06CH11357.
Electron beam driven wakefield acceleration is a bona fide path to reach high gradient acceleration of electrons and positrons. With the goal of demonstrating the feasibility of this concept with realistic parameters, well beyond a proof-of-principle scenario, the AWA Facility is currently undergoing a major upgrade that will enable it to achieve accelerating gradients of hundreds of MV/m and energy gains on the order of 100 MeV per structure. A key aspect of the studies and experiments carried out at the AWA facility is the use of relatively short RF pulses (15 – 25 ns), which is believed to mitigate the risk of breakdown and structure damage. The upgraded facility will utilize long trains of high charge electron bunches to drive wakefields in the microwave range of frequencies (8 to 26 GHz), generating RF pulses with GW power levels.

Slides MOPLB11 [0.900 MB]

MOPB005

High Gradient Operation of 8 GeV C-Band Accelerator in SACLA

laser, electron, klystron, free-electron-laser

186

T. Inagaki, C. Kondo, Y. Otake, T. Sakurai
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan

SACLA (SPring-8 angstrom compact free electron laser) is the X-ray free electron laser (XFEL) facility. In order to shorten the 8 GeV accelerator length, a C-band (5712 MHz) accelerator was employed. Since the accelerating gradient of C-band accelerating structure is 35 MV/m in nominal, the active accelerator length is 230 m. In total, 64 klystrons, 64 pulse compressors, and 128 accelerating structures are used. In order to withstand the high surface field (~ 100 MV/m), and to reduce the amount of dark current, which decreases the demagnetization effect of undulators, the accelerating structures are carefully fabricated in the factory.　After high power RF conditioning of 500 hours, the beam commissioning was started in February 2011. For night time of the commissioning, we continued the RF conditioning. The RF breakdown rate of the structure was steadily decreased. Now we operate the accelerator with the beam energy as much as 8.3 GeV, and the accelerating gradient of 37 MV/m in average. We found the amount of dark current is small enough. So far no trouble occurred in C-band RF components of 64 sets.

MOPB036

Feasibility Study of Short Pulse Mode Operation for Multi-turn ERL Light Source

linac, emittance, simulation, undulator

255

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

The optics and simulation group at HZB are designing Germany’s future light source. Based on the emerging Energy Recovery Linac super conducting technology, the Femto-Science-Factory (FSF) will provide its users with ultra-bright photons of Angstrom wavelength at 6 GeV. The FSF is intended to be a multi-user facility and offer a wide variety of operation modes. A low emittance ~0.1 μm rad mode will operate in conjunction with a short-pulse ~10 fs mode. This paper highlights the physical limitations when trying to offer interchangeable modes and preserve beam high quality.

MOPB037

Linac Optics Design for Multi-turn ERL Light Source

linac, cavity, optics, cryomodule

258

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

The optics simulation group at HZB is designing a multi-turn energy recovery linac-based light source. Using the superconducting Linac technology, the Femto-Science-Factory (FSF) will provide its users with ultra-bright photon beams of angstrom wavelength at 6 GeV. The FSF is intended to be a multi-user facility and offer a variety of operation modes. In this paper a design of transverse optic of the beam motion in the Linacs is presented. An important point in the optics design was minimization of the beta-functions in the linac at all beam passes to suppress beam break-up (BBU) instability.

MOPB041

Advances in Beam Tests of Dielectric Based Accelerating Structures

wakefield, electron, laser, linac

264

A. Kanareykin, S.P. Antipov, J.E. Butler, C.-J. Jing
Euclid TechLabs, LLC, Solon, Ohio, USA
W. Gai
ANL, Argonne, USA
V. Yakimenko
BNL, Upton, Long Island, New York, USA

Funding: US Department of Energy
Diamond is being evaluated as a dielectric material for dielectric loaded accelerating structures. It has a very low microwave loss tangent, high thermal conductivity, and supports high RF breakdown fields. We report on progress in our recent beam tests of the diamond based accelerating structures of the Ka-band and THz frequency ranges. Wakefield breakdown test of a diamond-loaded accelerating structure has been carried out at the ANL/AWA accelerator. The high charge beam from the AWA linac (~70 nC, σ_z = 2.5 mm) was passed through a rectangular diamond loaded resonator and induce an intense wakefield. A groove is cut on the diamond to enhance the field. Electric fields up to 0.3 GV/m has been detected on the diamond surface to attempt to initiate breakdown. A surface analysis of the diamond has been performed before and after the beam test. Wakefield effects in a 250 GHz planar diamond accelerating structure has been observed at BNL/ATF accelerator as well. We have directly measured the mm-wave wake fields induced by subpicosecond, intense relativistic electron bunches in a diamond loaded accelerating structure via the dielectric wake-field acceleration mechanism.

MOPB045

Specifications of the Distributed Timing System for the CLIC Main Linac

luminosity, linac, monitoring, collider

273

A. Gerbershagen, A. Andersson, D. Schulte
CERN, Geneva, Switzerland
P. Burrows
JAI, Oxford, United Kingdom
F.Ö. Ilday
Bilkent University, Bilkent, Ankara, Turkey

The longitudinal phase stability of CLIC main and drive beams is a crucial element of CLIC design. In order to measure and to control the phase, a distributed phase monitoring system has been proposed. The system measures the beam phase every 900 m. The relative phase between the measurement points is synchronized with an external reference system via a chain of reference lines. This paper presents the simulations of error propagation in the proposed distributed monitoring system and the impact on the drive and main beam phase errors and the luminosity. Based on the results the error tolerances for the proposed system are detailed.

MOPB062

A New Internal Optical Profilometry System for Characterization of RF Cavity Surfaces – CYCLOPS

cavity, controls, ion, feedback

318

C.E. Reece, A.D. Palczewski, H. Tian
JLAB, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Jefferson Lab has received and commissioned a new interferometric optical profilometer specifically designed to provide internal surface mapping of elliptical rf cavities. The CavitY CaLibrated Optical Profilometry System – CYCLOPS – provides better than 2 micron lateral resolution and 0.1 micron surface height resolution of programmatically selected locations on the interior surface of multi-cell cavities. The system is being used to provide detailed characterization of surface topographic evolution as a function of applied surface treatments and to investigate particular localized defects. We also intend to use the system for 3D mapping of actual interior rf surface geometry for feedback to structure design model and fabrication tooling. First uses will be illustrated. CYCLOPS was developed and fabricated by MicroDynamics Inc., Woodstock, GA, USA.

MOPB066

Alternative Approaches for HOM-Damped Cavities

multipole, cavity, HOM, linac

330

B. Riemann, T. Weis
DELTA, Dortmund, Germany
A. Neumann
HZB, Berlin, Germany

Funding: this work is partly funded by BMBF contract no. 05K10PEA
Elliptical cavities have been a standard in SRF linac technology for 30 years. We present another approach to base cell geometry based on Bezier splines, that leads to equal performance levels and is much more flexible in terms of optimization. Using the BERLinPro main linac as an example, a spline multicell cavity is designed with equal performance goals. For the damping of higher order modes (HOMs), the installation of waveguides at the ends of a multicell cavity is a common approach.

MOPB070

Quality Control of Cleanroom Processing Procedures of SRF Cavities for Mass Production

cavity, controls, SRF, diagnostics

339

R. Oweiss, K. Elliott, A. Facco, M. Hodek, I.M. Malloch, J. Popielarski, L. Popielarski, K. Saito
FRIB, East Lansing, Michigan, USA

Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661.
Quality control is a key factor in the success of SRF cavity mass production. This paper summarizes ongoing research at the Facility for Rare Isotope Beams FRIB to validate the quality assurance of SRF cavities meanwhile optimizing processing procedures for mass production. Experiments are conducted to correlate surface cleanliness for niobium surfaces with high pressure rinse time using β=0.085 quarter-wave resonators (QWR) cavities. Diagnostic devices; liquid particle counter, surface particle detector and TOC analyzer are used to monitor key parameters for quality control. Rinse water samples are collected during high pressure rinsing to measure liquid particle counts. The SLS 1200 Sampler is used to detect the presence of liquid particles of 0.2 microns and up to 1 micron to set standards for acceptable cleaning thresholds and optimize high pressure rinse time. The QIII+ surface particle detector is used to scan high electric field region for the β=0.085 QWR to ensure high pressure rinsing efficiency. The β=0.085 QWR RF testing data are analyzed and results are presented to demonstrate the correlation between attained acceleration gradients and surface cleanliness.

MOPB081

Travelling Wave Accelerating Structures with a Large Phase Advance

electron, linac, impedance, proton

363

V.V. Paramonov
RAS/INR, Moscow, Russia

The electrons acceleration is considered in higher pass bands of TM01 wave for disk loaded waveguide, resulting in the possibility of traveling wave accelerating structures with an operating field phase advance between 180 – 1260 degrees per cell. With an appropriate shape optimization and some additional elements in cells proposed traveling wave structures have small transverse dimensions and high RF efficiency of standing wave operation. Examples of proposed structures together with RF and dispersion properties are presented.

MOPB093

The Upgraded Argonne Wakefield Accelerator Facility (AWA): a Test-Bed for the Development of High Gradient Accelerating Structures and Wakefield Measurements

wakefield, electron, gun, linac

392

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

Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC02-06CH11357.
Electron beam driven wakefield acceleration is a bona fide path to reach high gradient acceleration of electrons and positrons. With the goal of demonstrating the feasibility of this concept with realistic parameters, well beyond a proof-of-principle scenario, the AWA Facility is currently undergoing a major upgrade that will enable it to achieve accelerating gradients of hundreds of MV/m and energy gains on the order of 100 MeV per structure. A key aspect of the studies and experiments carried out at the AWA facility is the use of relatively short RF pulses (15 – 25 ns), which is believed to mitigate the risk of breakdown and structure damage. The upgraded facility will utilize long trains of high charge electron bunches to drive wakefields in the microwave range of frequencies (8 to 26 GHz), generating RF pulses with GW power levels.

TUPLB08

R&D Towards CW Ion Linacs at ANL

cryomodule, rfq, cavity, ion

461

P.N. Ostroumov, A. Barcikowski, Z.A. Conway, S.M. Gerbick, M. Kedzie, M.P. Kelly, S.V. Kutsaev, J.W. Morgan, R.C. Murphy, B. Mustapha, D.R. Paskvan, T. Reid, D.L. Schrage, S.I. Sharamentov, K.W. Shepard, G.P. Zinkann
ANL, Argonne, USA

Funding: This work was supported by the U.S. Department of Energy, Office of High Energy Physics and Nuclear Physics, under Contract DE-AC02-76CH03000, DE-AC02-06CH11357 and ANL WFO 85Y47.
The accelerator development group in ANL’s Physics Division has engaged in substantial R&D related to CW proton and ion accelerators. Particularly, a 4 meter long 60.625 MHz CW RFQ has been developed, built and is being commissioned with beam. Development and fabrication of a cryomodule with seven 72.75 MHz quarter-wave cavities is complete and it is being assembled. Off-line testing of several QWRs has demonstrated outstanding performance in terms of both accelerating voltage and surface resistance. Both the RFQ and cryomodule were developed and built to upgrade ATLAS to higher efficiency and beam intensities. Another cryomodule with eight 162.5 MHz SC HWRs and eight SC solenoids is being developed and built for Project X at FNAL. We are also developing both an RFQ and cryomodules (housing 176 MHz HWRs) for proton & deuteron acceleration at SNRC (Soreq, Israel). In this paper we discuss ANL-developed technologies for normal-conducting and SC accelerating structures for medium- and high-power CW accelerators, including the projects mentioned above and other developments for applications such as transmutation of spent reactor fuel.

Slides TUPLB08 [1.414 MB]

TUPB026

Measurements of a Reduced Energy Spread of a Recirculating Linac by Non-isochronous Beam Dynamics

recirculation, linac, electron, synchrotron

531

F. Hug, C. Burandt, M. Konrad, N. Pietralla
TU Darmstadt, Darmstadt, Germany
R. Eichhorn
Cornell University, Ithaca, New York, USA

Funding: supported by DFG through SFB 634
The Superconducting Linear Accelerator S-DALINAC at the University of Darmstadt (Germany) is a recirculating linac with two recirculations providing beams for measurements in nuclear physics at small momentum transfers. For these experiments an energy spread of better than 10^-4 (rms) is needed. Currently acceleration in the linac section is done on crest of the accelerating field. The recirculation path is operated achromatic and isochronous. In this recirculation scheme the energy spread of the resulting beam in the ideal case is determined by the electron bunch length. Taking into account the stability of the RF system the energy spread increases drastically to more than 10^-3 (rms). We will present a new non-isochronous recirculation scheme which helps cancelling out these errors from the rf-control. This scheme uses longitudinal dispersion in the recirculation paths and an acceleration off-crest with a certain phase with respect to the maximum. We will present results of the commissioning of the new system including measurements of the longitudinal dispersion in the recirculation arcs as well as measurements of the resulting energy spread using an electron spectrometer.

TUPB043

One Design of Heavy Ion Linac Injector for CSRm

linac, ion, heavy-ion, emittance

573

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

The design of heavy ion linac as one new injector of the main Cooling Storage Ring (CSRm) has been discussed. The linac design is based on interdigital H mode drift tube with KONUS (Kombinierte Null Grad Struktur). A high acceleration rate with zero degree synchronous particle phase acceleration reduce the length of IH-KONUS linac and the cost in comparison with conventional linac based on Alvarez structure. To reduce the effect of emittance growth, the RFQ structure is used in front of the IH-KONUS linac. In this linac, the design particle 238U²⁸⁺ will be accelerated to 7 AMeV, and the transmission of Uranium beam can reach up to 80%. In this report, the initial physics design of the main linac is presented.

TUPB046

R&D Towards CW Ion Linacs at ANL

cryomodule, rfq, cavity, ion

579

P.N. Ostroumov, A. Barcikowski, Z.A. Conway, S.M. Gerbick, M. Kedzie, M.P. Kelly, S.V. Kutsaev, J.W. Morgan, R.C. Murphy, B. Mustapha, D.R. Paskvan, T. Reid, D.L. Schrage, S.I. Sharamentov, K.W. Shepard, G.P. Zinkann
ANL, Argonne, USA

Funding: This work was supported by the U.S. Department of Energy, Office of High Energy Physics and Nuclear Physics, under Contract DE-AC02-76CH03000, DE-AC02-06CH11357 and ANL WFO 85Y47.
The accelerator development group in ANL’s Physics Division has engaged in substantial R&D related to CW proton and ion accelerators. Particularly, a 4 meter long 60.625 MHz CW RFQ has been developed, built and is being commissioned with beam. Development and fabrication of a cryomodule with seven 72.75 MHz quarter-wave cavities is complete and it is being assembled. Off-line testing of several QWRs has demonstrated outstanding performance in terms of both accelerating voltage and surface resistance. Both the RFQ and cryomodule were developed and built to upgrade ATLAS to higher efficiency and beam intensities. Another cryomodule with eight 162.5 MHz SC HWRs and eight SC solenoids is being developed and built for Project X at FNAL. We are also developing both an RFQ and cryomodules (housing 176 MHz HWRs) for proton & deuteron acceleration at SNRC (Soreq, Israel). In this paper we discuss ANL-developed technologies for normal-conducting and SC accelerating structures for medium- and high-power CW accelerators, including the projects mentioned above and other developments for applications such as transmutation of spent reactor fuel.

TUPB070

Development of Proton Therapy at the SC Linac with BEAMDULAC-SCL Code

linac, focusing, solenoid, proton

633

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

Proton cancer therapy complexes are conventionally developing based on synchrotrons and cyclotrons. High electrical power consumption and especial devices necessary to energy variation (as slow extraction systems and degraders) are the main problems of such complexes. At once SC linacs based on short independently phased quarter and half wave cavities have a serious progress at present. Linear accelerator consumes less power comparably with cyclic and the energy variation can be easily realized by means of RF field amplitude and phase variation in a number of cavities. The accelerator’s modular configuration which is now widely used in FRIBs * or SNSs can be applied for therapy linac also (see for example **). It is possible to choose the SC linac parameters and proton and ion beams stability study with help of the BEAMDULAC-SCL code. This software also allows providing of the structure optimization and the beam dynamics control.
* P.N. Ostroumov and et al., Proc. of PAC2001, p.4080.
** C.Ronsivalle et al. Proc. of IPAC 2011, p. 3580.

TUPB102

Design and Performances of Phase Monitor in J-PARC Linac

linac, pick-up, vacuum, impedance

699

A. Miura
JAEA/J-PARC, Tokai-mura, Japan
Z. Igarashi, T. Miyao
KEK, Ibaraki, Japan

J-PARC linac employs a fast current transformer (FCT) as a beam phase monitor to calculate the beam energy by time-of-flight method. We have installed and used 61 FCTs in the current beam line. Because the phase measurements at additional 41 points in the future ACS sections are required for the energy upgrade project with adding 21 ACS (Annular Coupled Structure) cavities, we stared the design and fabrication of FCTs as the phase measurement devices. In addition, J-PARC linac employs the 4-stripline beam position monitors (BPMs) for the beam position measurement. It has been considered that the signals from striplines of BPM would be useful for a phase measurement. A phase measurement using a BPM has been successfully conducted. In order to evaluate the performances of the FCT, the signal sensitivity and cut-off frequency of newly fabricated FCT are measured. Also, these data of the BPM are also measured to be compared with the data of FCT. Based on the results of the comparing both measurements, the superiority of both monitors for beam phase measurement is discussed.

WE2A01

RF Power Production at the Two Beam Test Stand at CERN

damping, recirculation, target, extraction

738

I. Syratchev
CERN, Geneva, Switzerland

The generation of short (250 ns) high peak power (135 MW) RF pulses by decelerating the high current (100 A) bunched (12 GHz) drive beam is one of the key components in the CLIC two beam acceleration scheme. Recent tests with drive beam deceleration at CERN's CTF3, using specially developed 1 m long CLIC Power Extraction and Transfer Structure (PETS) operated in re-circulation regime have successfully demonstrated this concept. The results of these tests are presented.

Slides WE2A01 [2.636 MB]

TH3A04

Plasmas, Dielectrics and the Ultrafast: First Science and Operational Experience at FACET

plasma, electron, radiation, linac

802

C.I. Clarke, E. Adli, S. Corde, F.-J. Decker, R.J. England, R.A. Erickson, A.S. Fisher, S.J. Gessner, C. Hast, M.J. Hogan, S.Z. Li, N. Lipkowitz, M.D. Litos, Y. Nosochkov, J.T. Seeman, J. Sheppard, I. Tudosa, G.R. White, U. Wienands, M. Woodley, Z. Wu, G. Yocky
SLAC, Menlo Park, California, USA
C.E. Clayton, C. Joshi, W. Lu, K.A. Marsh, N. Vafaei
UCLA, Los Angeles, California, USA

Funding: Work supported by the U.S. Department of Energy under contract number DE-AC02-76SF00515.
FACET (Facility for Advanced Accelerator and Experimental Tests) is an accelerator R&D test facility that has been recently constructed at SLAC National Accelerator Laboratory. The facility provides 20 GeV, 3 nC electron beams, short (20 um) bunches and small (20 um wide) spot sizes, producing uniquely high power beams. FACET supports studies from many fields but in particular those of Plasma Wakefield Acceleration and Dielectric Wakefield Acceleration. FACET is also a source of THz radiation for material studies. We present the FACET design, initial operating experience and first science from the facility.

Slides TH3A04 [3.091 MB]

THPB050

RFQ With Improved Energy Gain

rfq, simulation, ion, emittance

966

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

RFQ structure is practically only one choice for using in front ends of ion linacs for acceleration up to energy about 3 MeV. This limit is due to its relatively low acceleration efficiency. However it isn’t intrinsic feature of RFQ principle. It is defined only by vane geometry of conventional RFQ structure with sinusoidal modulation of vanes. The paper presents results of analysis RFQ with modified vane geometries that allow to improve acceleration efficiency. RFQ with modified vanes was used for design second section of heavy ion injector of TWAC for acceleration of ions with Z/A = 0.33 up to 7 MeV/u.

THPB095

Designing of a Phase-mask-type Laser Driven Dielectric Accelerator for Radiobiology

laser, electron, simulation, vacuum

1041

K. Koyama
UTNL, Ibaraki, Japan
A. Aimidura, M. Uesaka
The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan
Y. Matsumura
University of Tokyo, Tokyo, Japan
T. Natsui, M. Yoshida
KEK, Ibaraki, Japan

Funding: This work is supported by KAKENHI, Grant-in-Aid for Scientific Research (C) 24510120
In order to estimate the health risk of a low radiation dose, basic processes of the radiobiology should be clarified by shooting a DNA using a spatially and temporary defined particle beam or X-ray. A suitable beam size is as small as a resolving power of an optical microscope of a few hundred nanometers. Photonic crystal accelerators (PCA) are capable of delivering nm-beams of sub-fs pulses because the characteristic length and frequency of PCAs are on the order of the laser light. Since the phase-mask type accelerator has a simpler structure than other types of PCAs, we are designing a phase-mask type laser driven dielectric accelerator. By adopting an unbalanced length of pillar and ditch (grating) of 4:1, a standing wave like acceleration field is produced in a acceleration channel. A pillar height and initial speed of injected electron are determined by analytically. The maximum acceleration gradient of 2 GeV/m is estimated. The required laser power is roughly estimated to be 6.5 GW. The simulation using CST-code also shows similar values to accelerate electrons by the phase-mask type accelerator.