LINAC2014 - List of Keywords (klystron)

Paper	Title	Other Keywords	Page
MOPP004	Design and Development of Pulsed Modulators for RF Electron Linacs	linac, electron, gun, operation	55
	K.P. Dixit, S. Chandan, N. Chaudhary, R.B. Chavan, L.M. Gantayet, S.R. Ghodke, M. Kumar, K.C. Mittal, H.E. Sarukte, A.R. Tillu, H. Tyagi, V. Yadav BARC, Mumbai, India
	Pulsed Modulators required for RF sources, based on klystrons and magnetrons, for RF electron linacs have been designed and developed at Electron Beam Centre, BARC, Mumbai, India. Electron guns in these linacs have also been powered by pulsed modulators. Line-type modulators, as well as IGBT-based solid-state modulators have been developed for these applications. A 150 kV/100 A line-type modulator has been tested on klystron to generate 7 MW peak RF Power. Magnetron modulator has undergone testing up to 40 kV, 165 A on resistive load. Solid-state modulator, using fractional-turn pulse transformer has been designed, developed and tested successfully on magnetron load up to output power of 1.3 MW peak. A transformerless solid-state modulator for electron gun of 6 MeV cargo-scanning linac, uses the Marx adder configuration and has been successfully tested up to 40 kV. In addition, line-type modulators for electron guns up to 85 kV have been successfully commissioned and are in operation in the linac systems. This paper describes the salient design features of these modulators, development of pulse transformers, details of test set-up and discusses the test results of these modulators.
	Poster MOPP004 [2.343 MB]

MOPP024	Perspectives of the S-Band Linac of FERMI	operation, linac, FEL, electron	105
	A. Fabris, P. Delgiusto, M. Milloch, C. Serpico Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy A. Grudiev CERN, Geneva, Switzerland
	The S-band linac of FERMI, the seeded Free Electron Laser (FEL) located at the Elettra laboratory in Trieste, has reached the peak on-crest electron energy of 1.55 GeV required for FEL-2 with the present layout. Different ways are being considered to extend the operating energy of the S-band linac up to 1.8 GeV. At the same time upgrades on the existing systems are investigated to address the requirements of operability of a users facility. This paper provides an overview of the developments that are under consideration and discusses the requirements and constraints for their implementation.

MOPP076	Construction of an Accelerator-based BNCT Facility at yhe Ibaraki Neutron Medical Research Center	target, neutron, linac, rfq	230
	M. Yoshioka, H. Kobayashi, T. Kurihara, S.-I. Kurokawa, H. Matsumoto, N. Matsumoto KEK, Ibaraki, Japan T. Hashirano, T. Sugano MHI, Hiroshima, Japan F. Hiraga Hokkaido University, Sapporo, Japan H. Kumada, Su. Tanaka Tsukuba University, Graduate School of Comprehensive Human Sciences, Ibaraki, Japan A. Matsumura, H. Sakurai Tsukuba University, Ibaraki, Japan N. Nagura, T. Ohba Nippon Advanced Technology Co. Ltd., Ibaraki-prefecture, Japan T.N. Nakamoto, T. Zagar Cosylab, Ljubljana, Slovenia T. Nakamura JAEA, Ibaraki-ken, Japan T. Ouchi ATOX, Ibaraki, Japan
	An accelerator-based BNCT (Boron Neutron Capture Therapy) facility is being constructed at the Ibaraki Neutron Medical Research Center. It consists of a proton linac of 80kW beam power with 8 MeV energy and 10mA average current, a beryllium target, and a moderator system to provide an epi-thermal neutron flux enough for patient treatment. The technology choices for this present system were driven by the need to site the facility in a hospital and where low residual activity is essential. The maximum neutron energy produced from an 8 MeV-proton is 6 MeV, which is below the threshold energy of the main nuclear reactions which produce radioactive products. The down side of this technology choice is that it produces a high density heat load on the target so that cooling and hydrogen aniti-blistering amelioration prevent sever challenges requiring successful R&D progress. The latest design of the target and moderator system shows that a flux of 4×10⁹ epi-thermal neutrons / cm² / sec can be obtained. This is much higher than the flux from the existing nuclear reactor based BNCT facility at JAEA ( JRR-4).

MOPP078	RF Power Systems for the FAIR Proton Linac	linac, proton, electronics, cavity	236
	J. Lesrel, C. Joly IPN, Orsay, France E. Plechov, A. Schnase, G. Schreiber, W. Vinzenz GSI, Darmstadt, Germany
	In the framework of collaboration between the FAIR project, GSI, and CNRS, the IPNO lab is in charge of providing the high power RF components for a cavity test stand and for the planned FAIR proton Linac. This Linac will be connected to the existing GSI synchrotron SIS18 for serving as an injector for the new FAIR facility. The 70 MeV FAIR proton Linac design contains a 3 MeV RFQ, and a DTL based on Cross-bar H-mode cavities (CH). It will operate with pulsed RF at 325.224 MHz with a width of 200 μs and a repetition rate of 4 Hz. The planned RF systems of the proton Linac will be presented as well as the description of the test stand. The first power test results are obtained with a Thales klystron developed jointly with CNRS. Three solid state amplifiers made by Sigmaphi Electronics for the bunchers will also be described in this paper.

MOPP098	Physical Starting of the First and Second Section of Accelerator Linac-800	electron, undulator, linac, gun	288
	V. Kobets, N. Balalykin, I.N. Meshkov, V. Minashkin, G. Shirkov JINR, Dubna, Moscow Region, Russia V. Shabratov JINR/VBLHEP, Moscow, Russia
	In the report discusses the modernization of linear electron accelerator MEA (Medium Energy Accelerator). The aim is to develop a set of MEAs based free-electron lasers, imposed a number of emission wavelengths from infrared to ultraviolet. In work presents the results of the physical starting of the first and second stations accelerating electron linear accelerator LINAC-800, as well as start infrared undulator. We discuss the work program for this accelerator.

MOPP114	SNS Linac Upgrade Plans for the Second Target Station	linac, cryomodule, cavity, rfq	320
	J. Galambos, D.E. Anderson, M.P. Howell, S.-H. Kim, M.A. Plum, A.P. Shishlo ORNL, Oak Ridge, Tennessee, USA M.E. Middendorf ORNL RAD, Oak Ridge, Tennessee, USA
	Funding: ORNL is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. The Second Target Station (STS) upgrade for the Spallation Neutron Source (SNS) proposes the addition of a short pulse, long wavelength neutron scattering station. In order to provide world-class intensity at the additional station, the SNS linac beam power capability is doubled, to 2.8 MW. This will be accommodated by a 30% increase in the beam energy to 1.3 GeV and a 50% increase in beam current. The beam energy increase will be provided by the addition of 7 additional cyro-modules and supporting RF equipment in space provided during the original SNS construction. The beam current increase will be provided by improved ion source and a reduced chopping fraction, and will require increases in the RF and high voltage modulator systems to accommodate the additional beam loading. Initial plans will be presented. The proposed linac upgrade path will be described.

MOPP118	C-Band Load Development for the High Power Test of the SwissFEL RF Pulse Compressor	impedance, cavity, vacuum, coupling	329
	A. Citterio, J. Stettler, R. Zennaro PSI, Villigen PSI, Switzerland
	The SwissFEL C-band Linac will have 26 RF modules, each one consisting of a solid-state modulator and a 50 MW klystron that feeds a pulse compressor and four two meters long accelerating structures. The pulse compressor is of the Barrel Open Cavity type (BOC). A first prototype was successfully produced and high-power tested, reaching for full power klystron operation a peak power of 300 MW. For testing this BOC at maximum RF power, a broadband load was designed and built, based on a ridge waveguide design and high permeability stainless steel. Based on the experience gained at CERN for CLIC X-band high power loads, the RF design of the load was optimized to ensure high losses for a quite large range of magnetic steels. Test pieces were realized in three different magnetic steels to choose the best suited material commercially available. This paper reports about the RF design, material study, production and impressive high power results of this C-band load.

MOPP119	Measurements and High Power Test of the First C-band Accelerating Structure for SwissFEL	operation, vacuum, FEL, linac	333
	R. Zennaro, J. Alex, A. Citterio, J.-Y. Raguin PSI, Villigen PSI, Switzerland
	The SwissFEL project is based on a 5.8 GeV C-band Linac which is composed of 10⁴ accelerating structures with a length of 2 m each. Due to the absence of dimple tuning no local frequency correction is possible and hence ultra-precise machining is required. The paper reports on both low level and high power RF test of the first nominal structure produced. The required mechanical precision has been reached and the structure has been successfully power tested to a gradient larger than 50 MV/m, well above the nominal level of 28 MV/m. The measured dark current and break down rates are well in the specifications.

MOPP123	Development Activities of Accelerator Instruments for SACLA	controls, acceleration, cavity, laser	342
	Y. Otake, T. Asaka, T. Inagaki, C. Kondo, H. Maesaka, T. Ohshima, T. Sakurai, K. Togawa RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan H. Ego, S. Matsubara JASRI/SPring-8, Hyogo-ken, Japan
	The X-ray free-electron laser, SACLA, is constantly operated for user experiments aimed at new science. Experimental users demand further experimental abilities, such as many experimental chances by using multi-X-ray beam lines, much better repeatability of the experiment conditions and further intense high-energy X-rays. To equip SACLA with these abilities in the future, we have developed a 2pi /3 CG acceleration structure with an acceleration gradient of over 45 MV/m to adapt operation for generating the intense high-energy X-rays. A high-voltage power supply to charge the PFN of a modulator, a klystron and an acceleration structure were developed to adapt operation for 120 pps operation from the present 30 pps, since 120 pps is more suitable for beam distribution to the multi-beam lines. To meet the experimental repeatability realized by stable timing in a pump-probe experiment, an optical-fiber length control system to mitigate timing drift below 1 fs for 10 minutes was developed. Highly precise cavity temperature control system in an injector for below ±2mK was also realized. Performances of our developed instruments were experimentally tested to be sufficient for our demands.

TUIOB02	Beam Commissioning of the 100 MeV KOMAC Linac	proton, DTL, linac, operation	413
	Y.-S. Cho KAERI, Daejon, Republic of Korea
	Funding: This work was supported by the Ministry of Science, ICT & Future Planning of the Korean Government. The operation of the 100MeV proton linear accelerator for multipurpose application started in July, 2013 at KOMAC (Korea Multipurpose Accelerator Complex), KAERI (Korea Atomic Energy Research Institute). Also, the operation of the two beam lines, one is for 20MeV beam and the other for 100MeV beam, started in order to supply proton beams to users. The accumulated operation time was 2,290 hours and the proton beam was supplied to 937 samples in 2013. In addition to the beam service, the effort to increase the beam power is continuing in 2014. Beam commissioning and operation status of the linac will be presented in this talk.
	Slides TUIOB02 [7.200 MB]

TUIOB03	Commissioning of Energy Upgraded Linac of J-PARC	linac, injection, operation, rfq	417
	K. Hasegawa J-PARC, KEK & JAEA, Ibaraki-ken, Japan
	To realize a full potential of J-PARC facility (1MW at 3 GeV), the J-PARC linac is upgraded from 181 MeV to 400 MeV by using an annular-ring coupled structure linac (ACS). The ACS modules and peripheral system were installed and commissioned in summer to autumn of 2013. Beam commissioning is about to start and results will be expected.
	Slides TUIOB03 [4.905 MB]

TUPP009	Operation and Improvements of the ALBA Linac	linac, operation, injection, booster	459
	R. Muñoz Horta, J.M. Gómez Cordero, F. Pérez CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain
	The ALBA Light Source pre-injector is a 100 MeV electron Linac which started operation in July 2010. Since then, several improvements have been made to the Linac system to enhance the beam stability and the operation reliability with special focus to top-up mode operation requirements. A description of the modifications applied to the RF system and an overview of the different modes of injection are presented. Also operational experience in decay mode and in the recently implemented top-up mode are reported.

TUPP021	A New Type of Waveguide Distribution for the Accelerator Module Test Facility of the European XFEL	cryomodule, cavity, shielding, operation	475
	V.V. Katalev, S. Choroba DESY, Hamburg, Germany E.M. Apostolov MicroPlus-Apostolov Ltd., Sofia, Bulgaria A.A. Seliverstov s.p.a. FERRITE Ltd., St.Petersburg, Russia
	In order to test 100 superconducting accelerator modules within two years three test benches have been created in the accelerator module test facility (AMTF) to achieve the rate of one cryomodule per week. Each RF station of the test facility consists of a 5 MW klystron, at 1.3 GHz, 1.37 ms pulse width and 10 Hz repetition rate, and a waveguide distribution system. Each waveguide distribution supplies RF power to eight cavities, four times a pair of cavities. The distribution allows for a maximum power of 1 MW per cavity when the distribution is switched to mode supplying power to only four cavities. A new type of 1 MW isolator and a new compact 5 MW power divider have been developed to achieve that goal. Several cryomodule have been already successfully tested with this setup. We present the waveguide distribution for this test stand and describe the performance of the different elements.

TUPP023	Testing of the First Part of Series Production 10MW MBKs for the XFEL Project.	cathode, operation, gun, power-supply	481
	V. Vogel, L. Butkowski, A. Cherepenko, S. Choroba, J. Hartung, V.V. Kachaev, R. Wagner DESY, Hamburg, Germany
	At present more than half of 27 of 10 MW horizontal multi-beam klystrons (MBK) manufactured by two companies for the European XFEL project have been delivered to DESY. After delivery each klystron is connected to the connection module (CM), a HV oil tank with integrated HV connector, voltage and current monitors and a coaxial filament transformer, tested on the test stand and, if necessary conditioned. After this the klystrons are ready for installation in the underground linear accelerator tunnel. Two MBKs are already installed at the injector area of the XFEL. For the European XFEL project MBKs which can produce RF power of 10 MW, at RF frequency of 1.3 GHz, 1.5 ms pulse length and 10 Hz repetition rate, were chosen as RF power sources. During the incoming test the most important parameters of the MBK such as bandwidth, filament power, perveance, gain at different cathode voltage, phase stability and sensitivity to the solenoids current setting are measured and documented. In this paper we will give an overview of the test procedure, summarize the current test results and give a comparison of the most important parameters for several tubes.

TUPP029	Diagnostics and Analysis Techniques for High Power X-Band Accelerating Structures	diagnostics, timing, controls, operation	490
	A. Degiovanni, S. Döbert, W. Farabolini, I. Syratchev, W. Wuensch CERN, Geneva, Switzerland J. Giner Navarro IFIC, Valencia, Spain J. Tagg National Instruments Switzerland, Ennetbaden, Switzerland B.J. Woolley Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
	The study of high gradient limitations due to RF breakdowns is extremely important for the CLIC project. A series of diagnostic tools and analysis techniques have been developed in order to monitor and characterize the behaviour of CLIC accelerating structures under high power operation in the first CERN X-band klystron-based test stand (Xbox1). The data collected during the last run on a TD26r05 structure are presented in this paper. From the analysis of the RF power and phases, the location of the breakdowns inside the structure could be determined. Other techniques based on the field emitted dark current signals collected by Faraday cups placed at the two extremities of the structure have also been investigated. The results of these analyses are reported and discussed.

TUPP033	Effect of Beam-Loading on the Breakdown Rate of High Gradient Accelerating Structures	beam-loading, experiment, linac, acceleration	499
	J.L. Navarro Quirante, R. Corsini, A. Degiovanni, S. Döbert, A. Grudiev, O. Kononenko, G. McMonagle, S.F. Rey, A. Solodko, I. Syratchev, F. Tecker, L. Timeo, B.J. Woolley, X.W. Wu, W. Wuensch CERN, Geneva, Switzerland O. Kononenko SLAC, Menlo Park, California, USA A. Solodko JINR, Dubna, Moscow Region, Russia J. Tagg National Instruments Switzerland, Ennetbaden, Switzerland B.J. Woolley Cockcroft Institute, Lancaster University, Lancaster, United Kingdom X.W. Wu TUB, Beijing, People's Republic of China
	The Compact Linear Collider (CLIC) is a study for a future room temperature electron-positron collider with a maximum center-of-mass energy of 3 TeV. To efficiently achieve such high energy, the project relies on a novel two beam acceleration concept and on high-gradient accelerating structures working at 100 MV/m. In order to meet the luminosity requirements, the break-down rate in these high-field structures has to be kept below 10 per billion. Such gradients and breakdown rates have been demonstrated by high-power RF testing several 12 GHz structures. However, the presence of beam-loading modifies the field distribution for the structure, such that a higher input power is needed in order to achieve the same accelerating gradient as the unloaded case. The potential impact on the break-down rate was never measured before. In this paper we present an experiment located at the CLIC Test Facility CTF3 recently proposed in order to quantify this effect, layout and hardware status, and discuss its first results.
	Slides TUPP033 [1.970 MB]
	Poster TUPP033 [2.355 MB]

TUPP070	Status and Recent Modifications to 324-MHz RF Source in J-PARC LINAC	linac, operation, high-voltage, cathode	587
	M. Kawamura, Y. Fukui, K. Futatsukawa, F. Naito KEK, Ibaraki, Japan E. Chishiro, K. Hasegawa, F. Sato, S. Shinozaki JAEA/J-PARC, Tokai-mura, Japan T. Hori JAEA, Ibaraki-ken, Japan
	This paper describes the present status of and the recent modifications to the 324-MHz RF source in the J-PARC linac. The recovery from the Great East Japan Earthquake Disaster, the status of the 324-MHz klystrons, the failure of 3 high-voltage transformers (HVTRs), and the discharge suppression for the anode-modulators are described.
	Poster TUPP070 [0.660 MB]

TUPP096	LUE-200 Linac. Status & Development	neutron, linac, electron, beam-loading	653
	A.P. Sumbaev, A.S. Kayukov, V. Kobets, V. Minashkin, V.G. Pyataev, V.A. Shvets JINR, Dubna, Moscow Region, Russia V. Shabratov JINR/VBLHEP, Moscow, Russia V.N. Shvetsov JINR/FLNP, Moscow Region, Russia
	The general scheme and current status of an electron linear accelerator with an S-band travelling wave (f = 2856 MHz) accelerating structure – a driver for a pulsed neutron source (IREN) at the Frank Laboratory of Neutron Physics of the Joint Institute for Nuclear Research - are presented. The parameters of the accelerating system and the measured parameters of the electron beam – pulse-beam current, duration of the current pulse, repetition rate, electron-energy spectrum, and loading characteristics of the accelerating structure - are given. The beginning of the implementation of the project of the second stage of the IREN facility, which forms the basis for the development of the accelerator aimed at increasing its beam power, is reported. Technical solutions underlying the modernization of the accelerator’s electrophysical systems are discussed: accelerating system, RF power supplies,and modulators.

TUPP111	SwissFEL C-band LLRF Prototype System	LLRF, controls, feedback, electron	683
	A. Hauff, M. Broennimann, I. Brunnenkant, A. Dietrich, Z. Geng, F. Gärtner, M. Jurcevic, R. Kalt, S. Mair, A. Řežaeizadeh, L. Schebacher, T. Schilcher, W. Sturzenegger PSI, Villigen PSI, Switzerland
	SwissFEL is driven by more than 30 RF stations at different frequencies (S-, C-, X-band). To control the RF a new, in-house developed digital Low Level RF (LLRF) system measures up to 24 RF signals per station and performs a pulse-to-pulse feedback at a repetition rate of 100 Hz. The RF signals are down-converted to a common intermediate frequency. The state-of-the-art digital processing units are integrated into the PSI’s EPICS controls environment. Emphasis has been put on modularity of the system to provide a well-defined path for upgrades. Thus the RF front ends are separated from the digital processing units with their FMC standard interfaces for ADCs and DACs. A first prototype of the LLRF system consisting of the digital back end together with a C-band RF front end was installed in the SwissFEL C-band test facility. In this report the performance of the prototype system has been compared with the LLRF system requirements for SwissFEL. The critical parameters are high intra-pulse phase and amplitude resolutions, good channel-to-channel isolations, very low phase to amplitude modulation and a negligible temperature drift.

TUPP112	Study of a C-Band TW Electron Gun for SwissFEL	gun, cathode, emittance, cavity	686
	M. Schaer, A. Citterio, P. Craievich, L. Stingelin, R. Zennaro PSI, Villigen PSI, Switzerland
	For a future upgrade of the SwissFEL facility, the replacement of the S-band standing wave electron gun by a C-band standing wave, or traveling wave gun is investigated. The full model of the C-band TW gun is calculated with HFSS and is characterized by an almost vanishing group velocity in the first cell to increase the field at the cathode. ASTRA simulations predict that in the case of the C-band SW gun, a two times higher peak current of ~ 40 A can be generated while still preserving the low slice emittance of ~ 0.2 um at 200 pC, due to the higher electric field on cathode and improved magnetic focusing. This would help to halve the overall beam compression factor, relax the phase stability requirement of S- and X-band systems operated off-crest for compression and decrease the gain curve in theμbunch instability. Compared to the SW gun, a TW gun provides a more homogeneous acceleration and does not require any circulator. In this study, the preliminary RF design and beam performance of a C-band TW gun is presented and compared to a pure C-band SW gun presently under design at Paul Scherrer Institut and to the operating S-band SW gun.

TUPP123	Design of Novel RF Sources to Reduce the Beam Pace-Charge Effects	cavity, electron, space-charge, cathode	712
	M. Dal Forno, A. Jensen, R.D. Ruth, S.G. Tantawi SLAC, Menlo Park, California, USA
	Funding: DOE Traditional RF sources, such as Klystrons, TWT require a magnet (such as a solenoid) in order to maintain the electron beam focusing, compensating the particle repulsion caused by space charge effects. We designed a novel RF source with an alternative approach that reduces beam space charge problems. This paper shows the design of the device, with a new formulation of the Child’s Law, and the mode-beam stability analysis. The electron beam interaction with the cavity fields has been analyzed by means of particle tracking software in order to evaluate the beam bunching and the beam dynamics.
	Poster TUPP123 [0.172 MB]

WEIOA05	High Power RF Sources for the ESS RF Systems	linac, operation, DTL, rfq	756
	M. Jensen, G. Göransson, C. Marrelli, C. Martins, R. Montaño, A. Sunesson, R.A. Yogi, R. Zeng ESS, Lund, Sweden A.J. Johansson Lund University, Lund, Sweden
	The RF system for ESS will consist of around 150 high power RF sources and will deliver 125 MW peak power to the proton beam during the 2.86 ms pulse with an average power of 5 MW. The two RF frequencies, 352 and 704 MHz, the different power requirements along the linac and the sources currently available strongly influence the choice of RF technology. This talk will focus on the high power RF solutions for the main parts of the linac. We present an overview of the available technology along with the first test results of the main sources. Additionally, we will present the preliminary design of a new 1.2 MW multi-beam super power IOT being designed together with industry for the high beta section of the linac.
	Slides WEIOA05 [5.090 MB]

THIOC03	Operational Experience With CW High Gradient and High QL Cryomodules	cavity, cryomodule, controls, EPICS	834
	C. Hovater, T.L. Allison, R. Bachimanchi, E. Daly, M.A. Drury, G.E. Lahti, C.I. Mounts, R.M. Nelson, T. E. Plawski JLab, Newport News, Virginia, USA
	Funding: This manuscript has been authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The Continuous Electron Beam Accelerator Facility (CEBAF) energy upgrade from 6 GeV to 12 GeV includes the installation of ten new 100 MV cryomodules (80 cavities). The superconducting RF cavities are designed to operate CW at an accelerating gradient of 19.3 MV/m with a QL of 3×107. The RF system employs single cavity control using new digital LLRF controls and 13 kW klystrons. Recently, all of the new cryomodules and associated RF hardware and software have been commissioned and operated in the CEBAF accelerator. Electrons at linac currents up to 10 μA have been successfully accelerated and used for nuclear physics experiments. This paper reports on the commissioning and operation of the cryomodules and RF system.
	Slides THIOC03 [5.793 MB]

THPP004	Design, Development and Initial Results of Solid State Magnetron Modulator	distributed, induction, impedance, electron	843
	A.R. Tillu, S. Chandan, K.P. Dixit, K.C. Mittal, H.E. Sarukte BARC, Mumbai, India
	A prototype solid state pulse modulator based on Induction Adder Topology has been designed ans is currently being tested on a S Band Pulsed magnetron rated for 3.2M W Peak RF Power. After successful lab tests the modulator is intended for use in cargo scanning and radiography applications. Currently the topology consists of 4 no.s of single turn primaries driven independently at voltages not more than 1000V. The secondary encircles all the four primaries to generate the desired pulsed voltage across the magnetron. The designed output pulse parameters are 50k V, 120A, 4micro s, at a pulse repetition rate of 250 pps. The paper describes the design and development of the Epoxy Cast Pulse transformer and the Low Inductance Primary Circuit. The rise time measured was < 400ns, and the reverse voltage at the end of the pulse was less than 12kV (at 43k V pulse). The testing was done at low PRF, on two different magnetrons having different operating points to demonstrate fairly good impedance independent operating characteristic of the magnetron modulator. Initial test results on the Resistive load and Magnetron load will also be discussed
	Poster THPP004 [1.575 MB]

THPP027	Commissioning of the Linac4 Low Level RF and Future Plans	cavity, LLRF, linac, DTL	892
	P. Baudrenghien, J. Galindo, G. Hagmann, J. Noirjean, D. Stellfeld, D. Valuch CERN, Geneva, Switzerland
	Linac4 is a new 86-m long normal-conducting linear accelerator that will provide 160 MeV H⁻ to the CERN PS Booster (PSB), and replace the present 50 MeV proton Linac2. The Low Level RF (LLRF) system has to control the RFQ, two choppers, three bunching cavities, twenty two accelerating cavities and one debuncher in the transfer line to the PSB. To optimize the transfer into the 1 MHz PSB bucket, the machine includes fast choppers (synchronized with the PSB RF) and a voltage modulation of the last two cavities that will provide Longitudinal Painting for optimum filling. The commissioning in the tunnel with beam has started in October 2013. So far the part consisting of the RFQ, the three bunching cavities, and the first DTL is operational. The rest of the machine will be progressively commissioned till end 2015. The paper presents the LLRF system. First results from the commissioning (with a prototype regulation system) are shown and the more sophisticated algorithms under development are presented.

THPP125	Super-Compact SLED System Used in the LCLS Diagnostic System	cavity, electron, coupling, impedance	1151
	J.W. Wang, S.G. Tantawi, C. Xu SLAC, Menlo Park, California, USA
	Funding: * Work supported by Department of Energy contract DE–AC03–76SF00515. At SLAC, we have designed and installed an X-band radio-frequency transverse deflector system at the LCLS for measurement of the time-resolved lasing effects on the electron beam and extraction of the temporal profile of the pulses in routine operations. We have designed an X-Band SLED system capable design to augment the available klystron power and to double the kick.

THPP130	Development of FPGA-based Predistortion-type Linearization Algorithms for Klystrons within Digital LLRF Control Systems for ILC-like Electron Accelerators	controls, LLRF, target, FPGA	1162
	M. Omet Sokendai, Ibaraki, Japan B. Chase, P. Varghese Fermilab, Batavia, Illinois, USA T. Matsumoto, S. Michizono, T. Miura, F. Qiu KEK, Ibaraki, Japan
	Two different kinds of predistortion-type linearization algorithms have been implemented and compared on an FPGA within the digital LLRF control system the Advanced Superconducting Test Facility (ASTA) at the Fermi National Accelerator Laboratory (FNAL). The algorithms are based on 2nd order polynomial functions and lookup tables with interpolation by which complex correction factors are obtained. The algorithms were tested in an actual setup including a 5 MW klystron and a superconducting 9-cell TESLA-type cavity at ASTA. By this a proof of concept was demonstrated.
	Poster THPP130 [2.411 MB]

THPP139	800MeV Linear Accelerator Development for HLS Upgrade	linac, electron, operation, injection	1189
	K. Jin, Y. Hong, G. Huang, D. Jia, S.C. Zhang USTC/NSRL, Hefei, Anhui, People's Republic of China
	Hefei Light Source (HLS) was mainly composed of an 800 MeV electron storage ring and a 200 MeV constant-impedance Linac functioning as its injector in NSRL PhaseⅠ. A new Linac has been developed successfully in view of the Full Energy Injection and the Top-up Injection scheme will be adopted in the HLS upgrade. In this paper, an 800MeV linear accelerating system construction, the constant-gradient structure with the symmetry couplers will be described in detail. The microwave system, the manufacture technology, the RF measurement, the high power testing and the accelerating system operation with beam currents are presented.

Paper

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Other Keywords

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MOPP004

Design and Development of Pulsed Modulators for RF Electron Linacs

linac, electron, gun, operation

55

K.P. Dixit, S. Chandan, N. Chaudhary, R.B. Chavan, L.M. Gantayet, S.R. Ghodke, M. Kumar, K.C. Mittal, H.E. Sarukte, A.R. Tillu, H. Tyagi, V. Yadav
BARC, Mumbai, India

Pulsed Modulators required for RF sources, based on klystrons and magnetrons, for RF electron linacs have been designed and developed at Electron Beam Centre, BARC, Mumbai, India. Electron guns in these linacs have also been powered by pulsed modulators. Line-type modulators, as well as IGBT-based solid-state modulators have been developed for these applications. A 150 kV/100 A line-type modulator has been tested on klystron to generate 7 MW peak RF Power. Magnetron modulator has undergone testing up to 40 kV, 165 A on resistive load. Solid-state modulator, using fractional-turn pulse transformer has been designed, developed and tested successfully on magnetron load up to output power of 1.3 MW peak. A transformerless solid-state modulator for electron gun of 6 MeV cargo-scanning linac, uses the Marx adder configuration and has been successfully tested up to 40 kV. In addition, line-type modulators for electron guns up to 85 kV have been successfully commissioned and are in operation in the linac systems. This paper describes the salient design features of these modulators, development of pulse transformers, details of test set-up and discusses the test results of these modulators.

Poster MOPP004 [2.343 MB]

MOPP024

Perspectives of the S-Band Linac of FERMI

operation, linac, FEL, electron

105

A. Fabris, P. Delgiusto, M. Milloch, C. Serpico
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
A. Grudiev
CERN, Geneva, Switzerland

The S-band linac of FERMI, the seeded Free Electron Laser (FEL) located at the Elettra laboratory in Trieste, has reached the peak on-crest electron energy of 1.55 GeV required for FEL-2 with the present layout. Different ways are being considered to extend the operating energy of the S-band linac up to 1.8 GeV. At the same time upgrades on the existing systems are investigated to address the requirements of operability of a users facility. This paper provides an overview of the developments that are under consideration and discusses the requirements and constraints for their implementation.

MOPP076

Construction of an Accelerator-based BNCT Facility at yhe Ibaraki Neutron Medical Research Center

target, neutron, linac, rfq

230

M. Yoshioka, H. Kobayashi, T. Kurihara, S.-I. Kurokawa, H. Matsumoto, N. Matsumoto
KEK, Ibaraki, Japan
T. Hashirano, T. Sugano
MHI, Hiroshima, Japan
F. Hiraga
Hokkaido University, Sapporo, Japan
H. Kumada, Su. Tanaka
Tsukuba University, Graduate School of Comprehensive Human Sciences, Ibaraki, Japan
A. Matsumura, H. Sakurai
Tsukuba University, Ibaraki, Japan
N. Nagura, T. Ohba
Nippon Advanced Technology Co. Ltd., Ibaraki-prefecture, Japan
T.N. Nakamoto, T. Zagar
Cosylab, Ljubljana, Slovenia
T. Nakamura
JAEA, Ibaraki-ken, Japan
T. Ouchi
ATOX, Ibaraki, Japan

An accelerator-based BNCT (Boron Neutron Capture Therapy) facility is being constructed at the Ibaraki Neutron Medical Research Center. It consists of a proton linac of 80kW beam power with 8 MeV energy and 10mA average current, a beryllium target, and a moderator system to provide an epi-thermal neutron flux enough for patient treatment. The technology choices for this present system were driven by the need to site the facility in a hospital and where low residual activity is essential. The maximum neutron energy produced from an 8 MeV-proton is 6 MeV, which is below the threshold energy of the main nuclear reactions which produce radioactive products. The down side of this technology choice is that it produces a high density heat load on the target so that cooling and hydrogen aniti-blistering amelioration prevent sever challenges requiring successful R&D progress. The latest design of the target and moderator system shows that a flux of 4×10⁹ epi-thermal neutrons / cm² / sec can be obtained. This is much higher than the flux from the existing nuclear reactor based BNCT facility at JAEA ( JRR-4).

MOPP078

RF Power Systems for the FAIR Proton Linac

linac, proton, electronics, cavity

236

J. Lesrel, C. Joly
IPN, Orsay, France
E. Plechov, A. Schnase, G. Schreiber, W. Vinzenz
GSI, Darmstadt, Germany

In the framework of collaboration between the FAIR project, GSI, and CNRS, the IPNO lab is in charge of providing the high power RF components for a cavity test stand and for the planned FAIR proton Linac. This Linac will be connected to the existing GSI synchrotron SIS18 for serving as an injector for the new FAIR facility. The 70 MeV FAIR proton Linac design contains a 3 MeV RFQ, and a DTL based on Cross-bar H-mode cavities (CH). It will operate with pulsed RF at 325.224 MHz with a width of 200 μs and a repetition rate of 4 Hz. The planned RF systems of the proton Linac will be presented as well as the description of the test stand. The first power test results are obtained with a Thales klystron developed jointly with CNRS. Three solid state amplifiers made by Sigmaphi Electronics for the bunchers will also be described in this paper.

MOPP098

Physical Starting of the First and Second Section of Accelerator Linac-800

electron, undulator, linac, gun

288

V. Kobets, N. Balalykin, I.N. Meshkov, V. Minashkin, G. Shirkov
JINR, Dubna, Moscow Region, Russia
V. Shabratov
JINR/VBLHEP, Moscow, Russia

In the report discusses the modernization of linear electron accelerator MEA (Medium Energy Accelerator). The aim is to develop a set of MEAs based free-electron lasers, imposed a number of emission wavelengths from infrared to ultraviolet. In work presents the results of the physical starting of the first and second stations accelerating electron linear accelerator LINAC-800, as well as start infrared undulator. We discuss the work program for this accelerator.

MOPP114

SNS Linac Upgrade Plans for the Second Target Station

linac, cryomodule, cavity, rfq

320

J. Galambos, D.E. Anderson, M.P. Howell, S.-H. Kim, M.A. Plum, A.P. Shishlo
ORNL, Oak Ridge, Tennessee, USA
M.E. Middendorf
ORNL RAD, Oak Ridge, Tennessee, USA

Funding: ORNL is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.
The Second Target Station (STS) upgrade for the Spallation Neutron Source (SNS) proposes the addition of a short pulse, long wavelength neutron scattering station. In order to provide world-class intensity at the additional station, the SNS linac beam power capability is doubled, to 2.8 MW. This will be accommodated by a 30% increase in the beam energy to 1.3 GeV and a 50% increase in beam current. The beam energy increase will be provided by the addition of 7 additional cyro-modules and supporting RF equipment in space provided during the original SNS construction. The beam current increase will be provided by improved ion source and a reduced chopping fraction, and will require increases in the RF and high voltage modulator systems to accommodate the additional beam loading. Initial plans will be presented. The proposed linac upgrade path will be described.

MOPP118

C-Band Load Development for the High Power Test of the SwissFEL RF Pulse Compressor

impedance, cavity, vacuum, coupling

329

A. Citterio, J. Stettler, R. Zennaro
PSI, Villigen PSI, Switzerland

The SwissFEL C-band Linac will have 26 RF modules, each one consisting of a solid-state modulator and a 50 MW klystron that feeds a pulse compressor and four two meters long accelerating structures. The pulse compressor is of the Barrel Open Cavity type (BOC). A first prototype was successfully produced and high-power tested, reaching for full power klystron operation a peak power of 300 MW. For testing this BOC at maximum RF power, a broadband load was designed and built, based on a ridge waveguide design and high permeability stainless steel. Based on the experience gained at CERN for CLIC X-band high power loads, the RF design of the load was optimized to ensure high losses for a quite large range of magnetic steels. Test pieces were realized in three different magnetic steels to choose the best suited material commercially available. This paper reports about the RF design, material study, production and impressive high power results of this C-band load.

MOPP119

Measurements and High Power Test of the First C-band Accelerating Structure for SwissFEL

operation, vacuum, FEL, linac

333

R. Zennaro, J. Alex, A. Citterio, J.-Y. Raguin
PSI, Villigen PSI, Switzerland

The SwissFEL project is based on a 5.8 GeV C-band Linac which is composed of 10⁴ accelerating structures with a length of 2 m each. Due to the absence of dimple tuning no local frequency correction is possible and hence ultra-precise machining is required. The paper reports on both low level and high power RF test of the first nominal structure produced. The required mechanical precision has been reached and the structure has been successfully power tested to a gradient larger than 50 MV/m, well above the nominal level of 28 MV/m. The measured dark current and break down rates are well in the specifications.

MOPP123

Development Activities of Accelerator Instruments for SACLA

controls, acceleration, cavity, laser

342

Y. Otake, T. Asaka, T. Inagaki, C. Kondo, H. Maesaka, T. Ohshima, T. Sakurai, K. Togawa
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
H. Ego, S. Matsubara
JASRI/SPring-8, Hyogo-ken, Japan

The X-ray free-electron laser, SACLA, is constantly operated for user experiments aimed at new science. Experimental users demand further experimental abilities, such as many experimental chances by using multi-X-ray beam lines, much better repeatability of the experiment conditions and further intense high-energy X-rays. To equip SACLA with these abilities in the future, we have developed a 2pi /3 CG acceleration structure with an acceleration gradient of over 45 MV/m to adapt operation for generating the intense high-energy X-rays. A high-voltage power supply to charge the PFN of a modulator, a klystron and an acceleration structure were developed to adapt operation for 120 pps operation from the present 30 pps, since 120 pps is more suitable for beam distribution to the multi-beam lines. To meet the experimental repeatability realized by stable timing in a pump-probe experiment, an optical-fiber length control system to mitigate timing drift below 1 fs for 10 minutes was developed. Highly precise cavity temperature control system in an injector for below ±2mK was also realized. Performances of our developed instruments were experimentally tested to be sufficient for our demands.

TUIOB02

Beam Commissioning of the 100 MeV KOMAC Linac

proton, DTL, linac, operation

413

Y.-S. Cho
KAERI, Daejon, Republic of Korea

Funding: This work was supported by the Ministry of Science, ICT & Future Planning of the Korean Government.
The operation of the 100MeV proton linear accelerator for multipurpose application started in July, 2013 at KOMAC (Korea Multipurpose Accelerator Complex), KAERI (Korea Atomic Energy Research Institute). Also, the operation of the two beam lines, one is for 20MeV beam and the other for 100MeV beam, started in order to supply proton beams to users. The accumulated operation time was 2,290 hours and the proton beam was supplied to 937 samples in 2013. In addition to the beam service, the effort to increase the beam power is continuing in 2014. Beam commissioning and operation status of the linac will be presented in this talk.

Slides TUIOB02 [7.200 MB]

TUIOB03

Commissioning of Energy Upgraded Linac of J-PARC

linac, injection, operation, rfq

417

K. Hasegawa
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

To realize a full potential of J-PARC facility (1MW at 3 GeV), the J-PARC linac is upgraded from 181 MeV to 400 MeV by using an annular-ring coupled structure linac (ACS). The ACS modules and peripheral system were installed and commissioned in summer to autumn of 2013. Beam commissioning is about to start and results will be expected.

Slides TUIOB03 [4.905 MB]

TUPP009

Operation and Improvements of the ALBA Linac

linac, operation, injection, booster

459

R. Muñoz Horta, J.M. Gómez Cordero, F. Pérez
CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain

The ALBA Light Source pre-injector is a 100 MeV electron Linac which started operation in July 2010. Since then, several improvements have been made to the Linac system to enhance the beam stability and the operation reliability with special focus to top-up mode operation requirements. A description of the modifications applied to the RF system and an overview of the different modes of injection are presented. Also operational experience in decay mode and in the recently implemented top-up mode are reported.

TUPP021

A New Type of Waveguide Distribution for the Accelerator Module Test Facility of the European XFEL

cryomodule, cavity, shielding, operation

475

V.V. Katalev, S. Choroba
DESY, Hamburg, Germany
E.M. Apostolov
MicroPlus-Apostolov Ltd., Sofia, Bulgaria
A.A. Seliverstov
s.p.a. FERRITE Ltd., St.Petersburg, Russia

In order to test 100 superconducting accelerator modules within two years three test benches have been created in the accelerator module test facility (AMTF) to achieve the rate of one cryomodule per week. Each RF station of the test facility consists of a 5 MW klystron, at 1.3 GHz, 1.37 ms pulse width and 10 Hz repetition rate, and a waveguide distribution system. Each waveguide distribution supplies RF power to eight cavities, four times a pair of cavities. The distribution allows for a maximum power of 1 MW per cavity when the distribution is switched to mode supplying power to only four cavities. A new type of 1 MW isolator and a new compact 5 MW power divider have been developed to achieve that goal. Several cryomodule have been already successfully tested with this setup. We present the waveguide distribution for this test stand and describe the performance of the different elements.

TUPP023

Testing of the First Part of Series Production 10MW MBKs for the XFEL Project.

cathode, operation, gun, power-supply

481

V. Vogel, L. Butkowski, A. Cherepenko, S. Choroba, J. Hartung, V.V. Kachaev, R. Wagner
DESY, Hamburg, Germany

At present more than half of 27 of 10 MW horizontal multi-beam klystrons (MBK) manufactured by two companies for the European XFEL project have been delivered to DESY. After delivery each klystron is connected to the connection module (CM), a HV oil tank with integrated HV connector, voltage and current monitors and a coaxial filament transformer, tested on the test stand and, if necessary conditioned. After this the klystrons are ready for installation in the underground linear accelerator tunnel. Two MBKs are already installed at the injector area of the XFEL. For the European XFEL project MBKs which can produce RF power of 10 MW, at RF frequency of 1.3 GHz, 1.5 ms pulse length and 10 Hz repetition rate, were chosen as RF power sources. During the incoming test the most important parameters of the MBK such as bandwidth, filament power, perveance, gain at different cathode voltage, phase stability and sensitivity to the solenoids current setting are measured and documented. In this paper we will give an overview of the test procedure, summarize the current test results and give a comparison of the most important parameters for several tubes.

TUPP029

Diagnostics and Analysis Techniques for High Power X-Band Accelerating Structures

diagnostics, timing, controls, operation

490

A. Degiovanni, S. Döbert, W. Farabolini, I. Syratchev, W. Wuensch
CERN, Geneva, Switzerland
J. Giner Navarro
IFIC, Valencia, Spain
J. Tagg
National Instruments Switzerland, Ennetbaden, Switzerland
B.J. Woolley
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom

The study of high gradient limitations due to RF breakdowns is extremely important for the CLIC project. A series of diagnostic tools and analysis techniques have been developed in order to monitor and characterize the behaviour of CLIC accelerating structures under high power operation in the first CERN X-band klystron-based test stand (Xbox1). The data collected during the last run on a TD26r05 structure are presented in this paper. From the analysis of the RF power and phases, the location of the breakdowns inside the structure could be determined. Other techniques based on the field emitted dark current signals collected by Faraday cups placed at the two extremities of the structure have also been investigated. The results of these analyses are reported and discussed.

TUPP033

Effect of Beam-Loading on the Breakdown Rate of High Gradient Accelerating Structures

beam-loading, experiment, linac, acceleration

499

J.L. Navarro Quirante, R. Corsini, A. Degiovanni, S. Döbert, A. Grudiev, O. Kononenko, G. McMonagle, S.F. Rey, A. Solodko, I. Syratchev, F. Tecker, L. Timeo, B.J. Woolley, X.W. Wu, W. Wuensch
CERN, Geneva, Switzerland
O. Kononenko
SLAC, Menlo Park, California, USA
A. Solodko
JINR, Dubna, Moscow Region, Russia
J. Tagg
National Instruments Switzerland, Ennetbaden, Switzerland
B.J. Woolley
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
X.W. Wu
TUB, Beijing, People's Republic of China

The Compact Linear Collider (CLIC) is a study for a future room temperature electron-positron collider with a maximum center-of-mass energy of 3 TeV. To efficiently achieve such high energy, the project relies on a novel two beam acceleration concept and on high-gradient accelerating structures working at 100 MV/m. In order to meet the luminosity requirements, the break-down rate in these high-field structures has to be kept below 10 per billion. Such gradients and breakdown rates have been demonstrated by high-power RF testing several 12 GHz structures. However, the presence of beam-loading modifies the field distribution for the structure, such that a higher input power is needed in order to achieve the same accelerating gradient as the unloaded case. The potential impact on the break-down rate was never measured before. In this paper we present an experiment located at the CLIC Test Facility CTF3 recently proposed in order to quantify this effect, layout and hardware status, and discuss its first results.

Slides TUPP033 [1.970 MB]

Poster TUPP033 [2.355 MB]

TUPP070

Status and Recent Modifications to 324-MHz RF Source in J-PARC LINAC

linac, operation, high-voltage, cathode

587

M. Kawamura, Y. Fukui, K. Futatsukawa, F. Naito
KEK, Ibaraki, Japan
E. Chishiro, K. Hasegawa, F. Sato, S. Shinozaki
JAEA/J-PARC, Tokai-mura, Japan
T. Hori
JAEA, Ibaraki-ken, Japan

This paper describes the present status of and the recent modifications to the 324-MHz RF source in the J-PARC linac. The recovery from the Great East Japan Earthquake Disaster, the status of the 324-MHz klystrons, the failure of 3 high-voltage transformers (HVTRs), and the discharge suppression for the anode-modulators are described.

Poster TUPP070 [0.660 MB]

TUPP096

LUE-200 Linac. Status & Development

neutron, linac, electron, beam-loading

653

A.P. Sumbaev, A.S. Kayukov, V. Kobets, V. Minashkin, V.G. Pyataev, V.A. Shvets
JINR, Dubna, Moscow Region, Russia
V. Shabratov
JINR/VBLHEP, Moscow, Russia
V.N. Shvetsov
JINR/FLNP, Moscow Region, Russia

The general scheme and current status of an electron linear accelerator with an S-band travelling wave (f = 2856 MHz) accelerating structure – a driver for a pulsed neutron source (IREN) at the Frank Laboratory of Neutron Physics of the Joint Institute for Nuclear Research - are presented. The parameters of the accelerating system and the measured parameters of the electron beam – pulse-beam current, duration of the current pulse, repetition rate, electron-energy spectrum, and loading characteristics of the accelerating structure - are given. The beginning of the implementation of the project of the second stage of the IREN facility, which forms the basis for the development of the accelerator aimed at increasing its beam power, is reported. Technical solutions underlying the modernization of the accelerator’s electrophysical systems are discussed: accelerating system, RF power supplies,and modulators.

TUPP111

SwissFEL C-band LLRF Prototype System

LLRF, controls, feedback, electron

683

A. Hauff, M. Broennimann, I. Brunnenkant, A. Dietrich, Z. Geng, F. Gärtner, M. Jurcevic, R. Kalt, S. Mair, A. Řežaeizadeh, L. Schebacher, T. Schilcher, W. Sturzenegger
PSI, Villigen PSI, Switzerland

SwissFEL is driven by more than 30 RF stations at different frequencies (S-, C-, X-band). To control the RF a new, in-house developed digital Low Level RF (LLRF) system measures up to 24 RF signals per station and performs a pulse-to-pulse feedback at a repetition rate of 100 Hz. The RF signals are down-converted to a common intermediate frequency. The state-of-the-art digital processing units are integrated into the PSI’s EPICS controls environment. Emphasis has been put on modularity of the system to provide a well-defined path for upgrades. Thus the RF front ends are separated from the digital processing units with their FMC standard interfaces for ADCs and DACs. A first prototype of the LLRF system consisting of the digital back end together with a C-band RF front end was installed in the SwissFEL C-band test facility. In this report the performance of the prototype system has been compared with the LLRF system requirements for SwissFEL. The critical parameters are high intra-pulse phase and amplitude resolutions, good channel-to-channel isolations, very low phase to amplitude modulation and a negligible temperature drift.

TUPP112

Study of a C-Band TW Electron Gun for SwissFEL

gun, cathode, emittance, cavity

686

M. Schaer, A. Citterio, P. Craievich, L. Stingelin, R. Zennaro
PSI, Villigen PSI, Switzerland

For a future upgrade of the SwissFEL facility, the replacement of the S-band standing wave electron gun by a C-band standing wave, or traveling wave gun is investigated. The full model of the C-band TW gun is calculated with HFSS and is characterized by an almost vanishing group velocity in the first cell to increase the field at the cathode. ASTRA simulations predict that in the case of the C-band SW gun, a two times higher peak current of ~ 40 A can be generated while still preserving the low slice emittance of ~ 0.2 um at 200 pC, due to the higher electric field on cathode and improved magnetic focusing. This would help to halve the overall beam compression factor, relax the phase stability requirement of S- and X-band systems operated off-crest for compression and decrease the gain curve in theμbunch instability. Compared to the SW gun, a TW gun provides a more homogeneous acceleration and does not require any circulator. In this study, the preliminary RF design and beam performance of a C-band TW gun is presented and compared to a pure C-band SW gun presently under design at Paul Scherrer Institut and to the operating S-band SW gun.

TUPP123

Design of Novel RF Sources to Reduce the Beam Pace-Charge Effects

cavity, electron, space-charge, cathode

712

M. Dal Forno, A. Jensen, R.D. Ruth, S.G. Tantawi
SLAC, Menlo Park, California, USA

Funding: DOE
Traditional RF sources, such as Klystrons, TWT require a magnet (such as a solenoid) in order to maintain the electron beam focusing, compensating the particle repulsion caused by space charge effects. We designed a novel RF source with an alternative approach that reduces beam space charge problems. This paper shows the design of the device, with a new formulation of the Child’s Law, and the mode-beam stability analysis. The electron beam interaction with the cavity fields has been analyzed by means of particle tracking software in order to evaluate the beam bunching and the beam dynamics.

Poster TUPP123 [0.172 MB]

WEIOA05

High Power RF Sources for the ESS RF Systems

linac, operation, DTL, rfq

756

M. Jensen, G. Göransson, C. Marrelli, C. Martins, R. Montaño, A. Sunesson, R.A. Yogi, R. Zeng
ESS, Lund, Sweden
A.J. Johansson
Lund University, Lund, Sweden

The RF system for ESS will consist of around 150 high power RF sources and will deliver 125 MW peak power to the proton beam during the 2.86 ms pulse with an average power of 5 MW. The two RF frequencies, 352 and 704 MHz, the different power requirements along the linac and the sources currently available strongly influence the choice of RF technology. This talk will focus on the high power RF solutions for the main parts of the linac. We present an overview of the available technology along with the first test results of the main sources. Additionally, we will present the preliminary design of a new 1.2 MW multi-beam super power IOT being designed together with industry for the high beta section of the linac.

Slides WEIOA05 [5.090 MB]

THIOC03

Operational Experience With CW High Gradient and High QL Cryomodules

cavity, cryomodule, controls, EPICS

834

C. Hovater, T.L. Allison, R. Bachimanchi, E. Daly, M.A. Drury, G.E. Lahti, C.I. Mounts, R.M. Nelson, T. E. Plawski
JLab, Newport News, Virginia, USA

Funding: This manuscript has been authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
The Continuous Electron Beam Accelerator Facility (CEBAF) energy upgrade from 6 GeV to 12 GeV includes the installation of ten new 100 MV cryomodules (80 cavities). The superconducting RF cavities are designed to operate CW at an accelerating gradient of 19.3 MV/m with a QL of 3×107. The RF system employs single cavity control using new digital LLRF controls and 13 kW klystrons. Recently, all of the new cryomodules and associated RF hardware and software have been commissioned and operated in the CEBAF accelerator. Electrons at linac currents up to 10 μA have been successfully accelerated and used for nuclear physics experiments. This paper reports on the commissioning and operation of the cryomodules and RF system.

Slides THIOC03 [5.793 MB]

THPP004

Design, Development and Initial Results of Solid State Magnetron Modulator

distributed, induction, impedance, electron

843

A.R. Tillu, S. Chandan, K.P. Dixit, K.C. Mittal, H.E. Sarukte
BARC, Mumbai, India

A prototype solid state pulse modulator based on Induction Adder Topology has been designed ans is currently being tested on a S Band Pulsed magnetron rated for 3.2M W Peak RF Power. After successful lab tests the modulator is intended for use in cargo scanning and radiography applications. Currently the topology consists of 4 no.s of single turn primaries driven independently at voltages not more than 1000V. The secondary encircles all the four primaries to generate the desired pulsed voltage across the magnetron. The designed output pulse parameters are 50k V, 120A, 4micro s, at a pulse repetition rate of 250 pps. The paper describes the design and development of the Epoxy Cast Pulse transformer and the Low Inductance Primary Circuit. The rise time measured was < 400ns, and the reverse voltage at the end of the pulse was less than 12kV (at 43k V pulse). The testing was done at low PRF, on two different magnetrons having different operating points to demonstrate fairly good impedance independent operating characteristic of the magnetron modulator. Initial test results on the Resistive load and Magnetron load will also be discussed

Poster THPP004 [1.575 MB]

THPP027

Commissioning of the Linac4 Low Level RF and Future Plans

cavity, LLRF, linac, DTL

892

P. Baudrenghien, J. Galindo, G. Hagmann, J. Noirjean, D. Stellfeld, D. Valuch
CERN, Geneva, Switzerland

Linac4 is a new 86-m long normal-conducting linear accelerator that will provide 160 MeV H⁻ to the CERN PS Booster (PSB), and replace the present 50 MeV proton Linac2. The Low Level RF (LLRF) system has to control the RFQ, two choppers, three bunching cavities, twenty two accelerating cavities and one debuncher in the transfer line to the PSB. To optimize the transfer into the 1 MHz PSB bucket, the machine includes fast choppers (synchronized with the PSB RF) and a voltage modulation of the last two cavities that will provide Longitudinal Painting for optimum filling. The commissioning in the tunnel with beam has started in October 2013. So far the part consisting of the RFQ, the three bunching cavities, and the first DTL is operational. The rest of the machine will be progressively commissioned till end 2015. The paper presents the LLRF system. First results from the commissioning (with a prototype regulation system) are shown and the more sophisticated algorithms under development are presented.

THPP125

Super-Compact SLED System Used in the LCLS Diagnostic System

cavity, electron, coupling, impedance

1151

J.W. Wang, S.G. Tantawi, C. Xu
SLAC, Menlo Park, California, USA

Funding: * Work supported by Department of Energy contract DE–AC03–76SF00515.
At SLAC, we have designed and installed an X-band radio-frequency transverse deflector system at the LCLS for measurement of the time-resolved lasing effects on the electron beam and extraction of the temporal profile of the pulses in routine operations. We have designed an X-Band SLED system capable design to augment the available klystron power and to double the kick.

THPP130

Development of FPGA-based Predistortion-type Linearization Algorithms for Klystrons within Digital LLRF Control Systems for ILC-like Electron Accelerators

controls, LLRF, target, FPGA

1162

M. Omet
Sokendai, Ibaraki, Japan
B. Chase, P. Varghese
Fermilab, Batavia, Illinois, USA
T. Matsumoto, S. Michizono, T. Miura, F. Qiu
KEK, Ibaraki, Japan

Two different kinds of predistortion-type linearization algorithms have been implemented and compared on an FPGA within the digital LLRF control system the Advanced Superconducting Test Facility (ASTA) at the Fermi National Accelerator Laboratory (FNAL). The algorithms are based on 2nd order polynomial functions and lookup tables with interpolation by which complex correction factors are obtained. The algorithms were tested in an actual setup including a 5 MW klystron and a superconducting 9-cell TESLA-type cavity at ASTA. By this a proof of concept was demonstrated.

Poster THPP130 [2.411 MB]

THPP139

800MeV Linear Accelerator Development for HLS Upgrade

linac, electron, operation, injection

1189

K. Jin, Y. Hong, G. Huang, D. Jia, S.C. Zhang
USTC/NSRL, Hefei, Anhui, People's Republic of China

Hefei Light Source (HLS) was mainly composed of an 800 MeV electron storage ring and a 200 MeV constant-impedance Linac functioning as its injector in NSRL PhaseⅠ. A new Linac has been developed successfully in view of the Full Energy Injection and the Top-up Injection scheme will be adopted in the HLS upgrade. In this paper, an 800MeV linear accelerating system construction, the constant-gradient structure with the symmetry couplers will be described in detail. The microwave system, the manufacture technology, the RF measurement, the high power testing and the accelerating system operation with beam currents are presented.