IPAC2014 - List of Keywords (klystron)

Paper	Title	Other Keywords	Page
MOYBA02	New Design Approaches for High Intensity Superconducting Linacs – The New ESS Linac Design	cryomodule, linac, cavity, emittance	23
	D.P. McGinnis ESS, Lund, Sweden
	The cost of the next generation of high intensity accelerators has become so large that no single institution can solely afford to fund the construction of the project. To fund these large projects, institutions have embarked on forming ambitious collaboration structures with other laboratories. To induce other laboratories to join the collaboration, compromises must be made in the accelerator technical design to offer interesting and challenging projects to partner institutions. The cost of high intensity hadron accelerators is largely driven by RF system. A new design philosophy different from the traditional approach is emerging for the high intensity frontier machines. Emittance preservation is often less of an issue as long as beam losses are kept low. At ESS modifications were introduced to the linac design. One of the major changes is the reduction of final energy and an increase of gradient and beam current. As a result the design now meets the cost objective but for the price of a higher risk. The accelerator system designer must then try to balance the cost and technical risks while also satisfying the interests and external goals of the partner laboratories.
	Slides MOYBA02 [2.277 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOYBA02
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MOOCA01	High Power Test Results of the SPARC C-Band Accelerating Structures	controls, accelerating-gradient, vacuum, operation	39
	D. Alesini, M. Bellaveglia, M.E. Biagini, R. Boni, P. Chimenti, R. Clementi, G. Di Pirro, R. D. Di Raddo, M. Ferrario, A. Gallo, V.L. Lollo INFN/LNF, Frascati (Roma), Italy M. Brönnimann, R. Kalt, T. Schilcher PSI, Villigen PSI, Switzerland L. Ficcadenti INFN-Roma, Roma, Italy L. Palumbo URLS, Rome, Italy
	The energy upgrade of the SPARC photo-injector at LNF-INFN (Italy) from 150 to more than 240 MeV will be done by replacing a low gradient S-Band accelerating structure with two C-band structures. The structures are Traveling Wave (TW) and Constant Impedance (CI), have symmetric axial input couplers and have been optimized to work with a SLED RF input pulse. In the paper we present the results of the low and high power RF tests on the two final fabricated structures that shown the feasibility of the operation at accelerating gradients larger than 35 MV/m.
	Slides MOOCA01 [6.242 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOOCA01
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MOPRO003	Towards Stable Acceleration in Linacs	acceleration, bunching, electron, linac	65
	A. Dubrovskiy Private Address, Geneve, Switzerland
	Ultra-stable and -reproducible high-energy particle beams with short bunches are needed in novel linear accelerators and, in particular, in the Compact Linear Collider CLIC. A passive beam phase stabilization system based on a bunch compression with a negative transfer matrix element R56 and acceleration at a positive off-crest phase is proposed. The motivation and expected advantages of the proposed scheme are outlined.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO003
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TUPRI077	Stabilization of Mid-infrared FEL by Feedback Controls	FEL, feedback, electron, gun	1745
	H. Zen, M. Inukai, T. Kii, K. Masuda, M. Mishima, H. Negm, H. Ohgaki, K. Okumura, K. Takami, K. Torgasin, Y. Tsugamura, K. Yoshida Kyoto University, Kyoto, Japan
	A Mid-Infrared Free Electron Laser facility, KU-FEL* has been developed for energy related sciences. A beam position monitor and feedback system was introduced to stabilize the FEL output power and wavelength. The long term stability of FEL power and wavelength has been drastically improved by the feedback control. The developed feedback system and its performance will be reported in the conference. *H. Zen, et al., Infrared Physics & Technology, vol.51, 382-385.
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WEPRO113	Status of the Radiation Source ELBE Upgrade	laser, electron, operation, radiation	2233
	P. Michel, T.E. Cowan, U. Lehnert, U. Schramm HZDR, Dresden, Germany
	ELBE is based on a 40 MeV superconducting Electron Linac able to operate in CW mode and provides manifold secondary user beams. The suite of secondary beams include: two free electron lasers operating in the IR/THz regime; a fast neutron beam; a Bremsstrahlung gamma-ray beam; a low-energy positron beam; and patented single-electron test beams. The primary electron beam is also used for radiobiology research, or in interaction with ultra-intense PW-class lasers. Through 2014 ELBE will be upgraded to a Centre for High Power Radiation Sources. The ELBE beam current was increased to 1.6 mA by using novel solid state RF amplifiers. The concept also contains additional broad and narrow band coherent THz sources and the development of a 500 TW TiSa Laser and even a 1.5 PW diode pumped laser system. Laser plasma electron acceleration and proton acceleration experiments for medical applications are planned. Additionally, coupled electron laser beam experiments like Thomson scattering or injection of ELBE electron into the laser plasma will be done.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO113
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WEPME003	Two Years Experience with the Upgraded ELBE RF System Driven by 20kW Solid State Amplifier Blocks (SSPA)	operation, linac, cavity, SRF	2257
	H. Büttig, A. Arnold, A. Büchner, M. Justus, M. Kuntzsch, U. Lehnert, P. Michel, R. Schurig, G.S. Staats, J. Teichert HZDR, Dresden, Germany
	Since January 2012 the Superconducting CW Linac ELBE is equipped and in permanent operation with four 20 kW Solid State Amplifier Blocks. The poster gives an overview on the design of the new RF system and the experience gained within the first two years of operation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME003
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WEPME009	Principles for Design of High Power Pulsed Microwave Devices and Devices with Low Operating Voltage for Accelerators	gun, electron, controls, solenoid	2273
	K.G. Simonov, A.A. Borisov, I.I. Golenitskiy, A.V. Mamontov, A.N. Yunakov ISTOK, Moscow Region, Russia O.A. Morozov Research and Production Co. "MAGRATEP", Fryazino, Russia
	The principle of obtaining the extra-high pulsed power at significantly lower operating voltages by creating klystrons with magnetron gun; location of several such klystrons in a single solenoid with a homogeneous magnetic field and summing their output capacities is proposed. The principle of designing of high-power klystron with multi-beam magnetron gun with anode modulation and several energy outputs is proposed. The principle of designing of high-power klystron magnetron gun with multi-beam magnetron gun with control electrode modulation and several energy outputs is proposed. Are given the results of theoretical studies demonstrating the feasibility of such devices and high-power microwave systems based on them. During development of principles of obtaining an extra-high power were used the design of single-beam klystron with magnetron gun with control electrode modulation created at RPC "Istok".
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME009
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WEPME010	Implementation of Single Klystron Working Mode at the ALBA Linac	linac, booster, operation, synchrotron	2276
	R. Muñoz Horta, J.M. Gómez Cordero, F. Pérez CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain
	ALBA is a third generation synchrotron light source whose injector consists of a 100 MeV Linac and a Booster that accelerates the beam up to the full energy, 3 GeV. Two pulsed klystrons are used to feed the Linac cavities. Klystron 1 feeds the bunching section and also the first accelerating structure. Klystron 2 feeds exclusively the second accelerating structure. Recently, a S-band switching system installed in the waveguide system allows us to use also Klystron 2 to power the low-energy section and operate the Linac at lower energy, around 65 MeV. So that injection into the Booster is still possible while, in the meantime, Klystron 1 can be connected to a dummy load for reparation. Therefore, the time response after a klystron failure is improved. Details of the waveguide upgrade and the results of the ALBA Linac operated with only one klystron are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME010
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WEPME016	Experience Operating an X-band High-Power Test Stand at CERN	network, controls, vacuum, LLRF	2288
	W. Wuensch, N. Catalán Lasheras, A. Degiovanni, S. Döbert, W. Farabolini, J.W. Kovermann, G. McMonagle, S.F. Rey, I. Syratchev, L. Timeo CERN, Geneva, Switzerland J. Tagg National Instruments Switzerland, Ennetbaden, Switzerland B.J. Woolley Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
	CERN has constructed and is operating a klystron-based X-band test stand, called Xbox-1, dedicated to the high-gradient testing of prototype accelerating structures for CLIC and other applications such as FELs. The test stand has now been in operation for a year and significant progress has been made in understanding the system, improving its reliability, upgrading hardware and implementing automatic algorithms for conditioning the accelerating structures. This experience is reviewed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME016
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WEPME021	Solid-state Pulsed Klystron Transmitters	high-voltage, operation, power-supply, flattop	2300
	K. Schrock, C. Chipman, M.P.J. Gaudreau, B.E. Simpson Diversified Technologies, Inc., Bedford, Massachusetts, USA
	Funding: Lawrence Berkeley National Laboratory Daresbury Laboratory Diversified Technologies, Inc. (DTI) is currently building and will deliver in early 2014 two solid-state pulsed klystron transmitters. Though not identical, the units are similar in design, and will be delivered to Lawrence Berkeley National Laboratory (LBNL) and Daresbury Laboratory in England. DTI’s goal across these two projects is to develop a complete package which can subsequently be marketed in the high peak power laboratory transmitter market. The modulator is a pulse transformer-coupled hybrid system, including ancillary klystron components (i.e., focus coil, socket) but not the actual klystron tube. Both systems employ a relatively simple modulator, consisting of an energy storage capacitor, a high voltage series switch, a step-up pulse transformer, and a passive pulse-flattening circuit. This arrangement gives an extremely flat pulse and allows the use of a moderate value of storage capacitor. The DTI switch can open or close as commanded, so the pulse width is adjusted by the gate pulse to the system.
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WEPME065	European XFEL RF Gun Commissioning and LLRF Linac Installation	LLRF, gun, linac, cryomodule	2427
	J. Branlard, G. Ayvazyan, V. Ayvazyan, L. Butkowski, M.K. Grecki, M. Hoffmann, F. Ludwig, U. Mavrič, S. Pfeiffer, H. Schlarb, Ch. Schmidt, H.C. Weddig, B.Y. Yang DESY, Hamburg, Germany S. Bou Habib, K. Czuba, M. Grzegrzółka, E. Janas, J. Piekarski, I. Rutkowski, R. Rybaniec, D. Sikora, L.Z. Zembala, M. Żukociński Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland W. Cichalewski, D.R. Makowski, A. Mielczarek, P. Perek, A. Piotrowski, T. Pożniak TUL-DMCS, Łódź, Poland S. Korolczuk, I.M. Kudla, J. Szewiński NCBJ, Świerk/Otwock, Poland K. Oliwa, W. Wierba IFJ-PAN, Kraków, Poland
	The European x-ray free electron laser (XFEL) is based on a 17.5 GeV super conducting pulsed linac and is scheduled to deliver its first beam in 2016. The first component of its accelerator chain, the RF gun, was installed in fall of 2013 and its commissioning is underway. This contribution gives an update on the low level radio frequency (LLRF) system development and installation for the XFEL. In particular, the installation, performance and conditioning results of the RF gun are presented. The subsequent steps toward LLRF components mass-production, testing and installation for the XFEL linac are also explained.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME065
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WEPME066	High Speed Digitial LLRF Feedbacks for Normal Conducting Cavity Operation	LLRF, gun, cavity, operation	2430
	M. Hoffmann, L. Butkowski, H. Schlarb, Ch. Schmidt DESY, Hamburg, Germany W. Köhler DESY Zeuthen, Zeuthen, Germany A. Piotrowski TUL-DMCS, Łódź, Poland I. Rutkowski, R. Rybaniec Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
	In the first half of the year 2014, the MTCA.4 based LLRF control system will be installed at several facilities (FLASH RF Gun, REGAE, PITZ, FLUTE/KIT). First tests during the last year show promising results in optimizing the system for high speed digital llrf feedbacks (reducing system latency, increase internal controller processing speed). In this contribution we will present further improvements in latency and performance optimization of the system, results and gained experience from the commisioning of the system at the metioned facilities.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME066
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WEPME070	Plans for the Implementation of an Intra-pulse Feedback on the Fermi Linac LLRF System	feedback, LLRF, linac, controls	2441
	M. Milloch, A. Fabris, F. Gelmetti, M. Predonzani Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
	FERMI is a single-pass linac-based FEL user-facility covering the wavelength range from 100 nm (12 eV) to 4 nm (310 eV) and is located next to the third generation synchrotron radiation facility Elettra in Trieste, Italy. The 1.5 GeV S-band linac is composed of fifteen 3 GHz 45 MW peak RF power plants powering the gun, sixteen accelerating sections and the RF deflectors. The requirements on beam quality impose tight specifications on the stability of the electromagnetic fields that can be achieved only installing high reliable and high performance state of the art LLRF systems. While these requirements are presently met by the system installed, the on-going upgrade of the processing board with the final one will allow to add new functionalities of the system. One of the possible developments is the implementation of an intra-pulse feedback that will allow to apply the corrections inside the RF pulse. This paper provides an overview of the additional benefits that could be achieved and discusses the requirements and the constraints for the implementation in the machine.
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WEPME071	Development and Construction Status of New LLRF Control System for SuperKEKB	controls, cavity, LLRF, FPGA	2444
	T. Kobayashi, K. Akai, K. Ebihara, A. Kabe, K. Nakanishi, M. Nishiwaki, J.-I. Odagiri KEK, Ibaraki, Japan H. Deguchi, K. Hayashi, T. Iwaki, M. Ryoshi Mitsubishi Electric TOKKI Systems, Amagasaki, Hyogo, Japan
	Beam commissioning of the SuperKEKB will be started in 2015. A new LLRF control system, which is an FPGA-based digital RF feedback control system on the MicroTCA platform, has been developed to satisfy the requirement for high current beam operation of the SuperKEKB. Then final refinements were applied, and now the quantity production is in progress. As a new function, klystron phase lock loop was additionally implemented within the cavity feedback control loop in the FPGA, and it was successfully worked in the low-level operation test. For the SuperKEKB, damping ring (DR) is required for the positron injection. Therefore another new LLRF control system is under development for the DR-RF system. It is operated at the same RF-frequency as the main ring, and vector sum control of three cavities is needed in the DR-LLRF control. In this report, the development status and progress from the previous report will be presented including the RF reference distribution system.
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WEPME078	Experimental Test of the Prototype LLRF Systems for PAL-XFEL	LLRF, target, feedback, impedance	2462
	J. Hu, H. Heo, J.H. Hong, W.H. Hwang, H.-S. Kang, H.-S. Lee, C.-K. Min PAL, Pohang, Kyungbuk, Republic of Korea
	Two prototype LLRF systems were developed in collaboration with Pohang Accelerator Laboratory(PAL) and domestic companies. They are focused on the control of single klystron system to obtain mainly analogue performance. The low power test of the developed LLRF showed good performance previously. We experimentally tested LLRF in the klystron systems to see performance in the high power situation. They showed performance around the prototype specification for short time and relatively long time. During test some bugs are discovered and fixed.
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WEPRI072	High Power Co-axial Couplers for SRF Cavities	Windows, SRF, simulation, network	2657
	J. Guo, J. Henry, R.A. Rimmer, H. Wang, R.S. Williams JLab, Newport News, Virginia, USA A. Dudas, M.L. Neubauer Muons, Inc, Illinois, USA
	Funding: Work supported by Dept. of Energy grant no. DE-SC0002769 High Power RF couplers are required in a wide range of accelerator projects using superconducting RF cavities. We have proposed a novel robust coax SRF coupler design using two pre-stressed disc windows without the need of additional matching elements. The matching frequency and the power handling capacity can be easily scaled by changing the diameter and the spacing of the windows. In this paper, we will present our latest progress in the fabrication and the testing of the windows.
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THPPA02	Gersch Budker Prize Presentation	collider, linear-collider, electron, FEL	2846
	T. Shintake OIST, Onna-son, Okinawa, Japan
	SACLA: SPring-8 Angstrom Compact free-electron Laser, previously called XFEL/SPring-8, which is based on electron accelerator technology developed at SCSS project, in which C-band high gradient linear accelerator provides stable driving beams. Looking back upon 20 years R&D on C-band accelerator, I would like to give some advises to young scientists on doing research. The developed C-band accelerator is now providing 8 GeV electron beams at SACLA X-ray FEL in daily operation with the world best energy stability among these large scale machines.
	Slides THPPA02 [17.649 MB]
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THPRO019	Current Status of PAL-XFEL Project	undulator, linac, quadrupole, cavity	2897
	H.-S. Kang, K.W. Kim, I.S. Ko PAL, Pohang, Kyungbuk, Republic of Korea
	The PAL-XFEL, a 0.1-nm hard X-ray FEL facility consisting of a 10-GeV S-band linac, is being constructed in Pohang, South Korea. The installation of linac, undulator, and beam line will be completed by 2015. Its building construction is at its peak moment to be completed by December 2014. The major procurement contract was made in 2013 for the critical components of S-band linac modules and hard X-ray undulators. The commissioning will start in January 2016. We hope the first lasing will be achieved in early 2016.
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THPRO021	Results Produced after Measuring PAL-ITF Beam Diagnostic Instruments	pick-up, diagnostics, controls, laser	2903
	H. J. Choi, M.S. Chae, J.H. Hong, H.-S. Kang, S.J. Park PAL, Pohang, Kyungbuk, Republic of Korea
	Pohang Accelerator Laboratory (PAL) built a PAL-ITF at the end of 2012 to successfully complete PAL-XFEL in 2015. The PAL-ITF is equipped with various kinds of diagnostic equipment to produce high-quality electron bunches. An ICT and a Turbo-ICT were installed in the PAL-ITF. A Faraday Cup is installed at the end of the linear accelerator. These days, the quantity of electric charge occasionally is measured using a BPM Sum value. This paper focuses on the processes and results of electric charge quantity measurements using ICT, Turbo-ICT, FC and BPM. The PAL-ITF is equipped with Stripline-BPM. It is important to find a way to minimize measurement errors that can appear in the process of installing or measuring the BPM. For this, PAL-ITF separately measured the BPM electrode sensitivity and minimized BPM measurement errors through generally calibrating BPM devices by applying Lambertson's Method. A plan was made to minimize BPM measurement errors through applying the BPM electrical calibration method for BPM devices to be used by the PAL-XFEL. This paper examines the processes for checking the performance of the S-BPM installed in the PAL-ITF and the results of its measurements.
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THPRO025	Conceptual Design of a X-FEL Facility using CLIC X-band Accelerating Structure	linac, FEL, simulation, gun	2914
	A.A. Aksoy, O. Yavaş Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey D. Angal-Kalinin, J.A. Clarke Cockcroft Institute, Warrington, Cheshire, United Kingdom M.J. Boland SLSA, Clayton, Australia G. D'Auria, S. Di Mitri, C. Serpico Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy M. Doğan Dogus University, Istanbul, Turkey T.J.C. Ekelöf, R.J.M.Y. Ruber, V.G. Ziemann Uppsala University, Uppsala, Sweden W. Fang, Q. Gu SINAP, Shanghai, People's Republic of China A. Latina, D. Schulte, S. Stapnes, I. Syratchev, W. Wuensch CERN, Geneva, Switzerland Z. Nergiz Nigde University, Nigde University Science & Art Faculty, Nigde, Turkey
	Within last decade a linear accelerating structure with an average loaded gradient of 100 MV/m at 12 GHz has been demonstrated in the CLIC study. Recently, it has been proposed to use the CLIC structure to drive an FEL linac. In contrast to CLIC the linac would be powered by klystrons not by a drive beam. The main advantage of this proposal is achieving the required energies in a very short distance, thus the facility would be rather compact. In this study, we present the conceptual design parameters of a facility which could generate laser photon pulses covering the range of 1-75 Angstrom. Shorter wavelengths could also be reached with slightly increasing the energy.
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THPME171	General-purpose Spectrometer for Vacuum Breakdown Diagnostics for the 12 GHz Test Stand at CERN	electron, vacuum, simulation, diagnostics	3668
	M. Jacewicz, Ch. Borgmann, J. Ögren, R.J.M.Y. Ruber, V.G. Ziemann Uppsala University, Uppsala, Sweden
	Funding: This work is supported by the grants from the the Swedish Research Council DNR-2011-6305 and DNR-2009-6234. We discuss a spectrometer to analyze the electrons and ions ejected from a high-gradient CLIC accelerating structure that is installed in the klystron-driven 12 GHz test-stand at CERN. The charged particles escaping the structure provide useful information about the physics of the vacuum breakdown within a single RF pulse. The spectrometer consists of a dipole magnet, a pepper-pot collimator, a fluorescent screen and a fast camera. This enables us to detect both transverse parameters such as the emittance and longitudinal parameters such as the energy distribution of the ejected beams. We can correlate these measurements with e.g. the location of the breakdown inside the structure, by using information from the measured RF powers, giving in that way a complete picture of the vacuum breakdown phenomenon. The spectrometer was installed during Spring 2014 and will be commissioned during Summer 2014.
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THPRI031	Design and Commissioning of S-Band RF Station for AREAL Test Facility	gun, electron, LLRF, operation	3834
	A. Vardanyan, H. Avdishyan, H. Davtyan, B. Grigoryan, L.H. Hakobyan, H. Poladyan CANDLE SRI, Yerevan, Armenia
	The RF station has been designed and constructed for AREAL Linac. The constructional features and commissioning results of RF system are presented. The whole RF system is designed to work at 3GHz frequency. The linac includes an electron gun for 0.5-8 ps electron bunch production with 1-10 Hz repetition rate. For linac RF control system a Libera LLRF stabilization system is used. An important feature of the presented system is a high level synchronization of amplitude-phase characteristics which provide the required accuracy for particle acceleration and bunch formation.
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THPRI041	Twenty Years of Operation of the Elettra RF System	operation, cavity, storage-ring, booster	3853
	C. P. Pasotti, M. Bocciai, P. Pittana, M. Rinaldi Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
	Six thousand hours per year is the typical running scheduled time of the user-dedicated Elettra facility and twenty years is a significant amount of operating hours for the RF system. Failure and weak points of the installed equipment is discussed as well as the up-time statistic. The effectiveness of the predictive versus the extraordinary maintenance is presented. The gained operational experience has allowed the planning of the priorities to refit the installed components within a reasonable budget, in compliance with the user-operation time schedule and following the technical need of upgrading to improve the RF system performance.
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THPRI044	Vacuum Waveguide System for SPring-8 Linac Injector Section	vacuum, linac, electron, operation	3863
	T. Taniuchi, H. Dewa, H. Hanaki, T. Kobayashi, T. Magome, A. Mizuno, S. Suzuki, K. Yanagida JASRI/SPring-8, Hyogo-ken, Japan
	An SF6 waveguide system for the injector section of SPring-8 linac has been replaced in a vacuum waveguide system including a newly developed vacuum circulator and an isolator. This paper describes developed RF components, a waveguide configuration and an RF conditioning of the system.
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THPRI058	RF Delivery System for FETS	rfq, rf-amplifier, quadrupole, simulation	3902
	S.M.H. Alsari, M. Aslaninejad, J.K. Pozimski, P. Savage Imperial College of Science and Technology, Department of Physics, London, United Kingdom M. Dudman, A.P. Letchford STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
	The Front End Test Stand (FETS) is an experiment based at the Rutherford Appleton Laboratory (RAL) in the UK. In this experiment, the first stages necessary to produce a very high quality, chopped H⁻ ion beam as required for the next generation of high power proton accelerators (HPPAs) are designed, built and tested. HPPAs with beam powers in the megawatt range have many possible applications including drivers for spallation neutron sources, neutrino factories, accelerator driven sub-critical systems, waste transmuters and tritium production facilities. An RF system outline, circulator high power tests, RF amplifiers tests, waveguide run with shielding and couplers design are presented and discussed in this paper. Experimental measurements of the system’s circulator and RF Amplifiers high power test will be presented as part of the system testing results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI058
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THPRI078	Experimental Study of Surface RF Magnetic Field Enhancement Caused by Closely Spaced Protrusions	cavity, vacuum, superconductivity, experiment	3949
	F.Y. Wang, C. Adolphsen, J.P. Eichner, C.D. Nantista, L. Xiao SLAC, Menlo Park, California, USA
	The RF magnetic field enhancement between two closely spaced protrusions on a metallic surface has been studied theoretically. It is found that a large enhancement occurs when the field is perpendicular to the gap between the protrusions. This mechanism could help explain the melting that has been observed on cavity surfaces subjected to pulsed heating that would nominally be well below the melting temperature of the surface material. To test this possibility, an experiment was carried out in which a pair of copper “pins” was attached to the base plate of an X-band cavity normally used to study pulsed heating. Melting was observed between the pins when the predicted peak temperature was near or exceeded the copper melting temperature.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI078
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THPRI079	RF BREAKDOWN IN A GAS-FILLED TE01 CAVITY	cavity, plasma, electron, simulation	3952
	F.Y. Wang, C. Adolphsen, C.D. Nantista SLAC, Menlo Park, California, USA
	An L-band (1.3 GHz) TE01 mode pillbox cavity has been designed to study rf breakdown in gas. Since there are no surface electric fields, effects from the electron interaction with the surface should not be present as in the DC breakdown case. A CCD camera was used to measure the integrated light pattern through holes in the cavity, and an ultrafast diode was used to observed the evolution of the plasma during breakdown. Some preliminary results of the tests are presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI079
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THPRI100	Distributed Cooling System for the AREAL Test Facility	gun, electron, operation, controls	4010
	V. V. Vardanyan, G.A. Amatuni, V.S. Avagyan, A.A. Gevorgyan, B. Grigoryan, T.H. Mkrtchyan, V. Sahakyan, A.S. Simonyan, A.V. Tsakanian, A. Vardanyan CANDLE SRI, Yerevan, Armenia
	Following the design specifications of the Advanced Research Electron Accelerator Laboratory (AREAL), a reliable distributed cooling system for the AREAL linear accelerator has been developed. The cooling system provides a high accuracy temperature control for the electron gun, klystron and the magnets. The main requirements and technical solutions for various accelerator components cooling units are presented, including the local and remote control.
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FRXAB01	Trends in RF Technology for Applications to Light Sources with Great Average Power	operation, rf-amplifier, high-voltage, power-supply	4065
	Ch. Wang NSRRC, Hsinchu, Taiwan
	RF systems are a major part of both the capital and operating costs of contemporary light sources and directly impact their capability, reliability and availability. The RF community has been discussing for many years the best choice of CW RF power source for light sources. In the domain of great average power, the choice is among a klystron, inductive-output tube, and solid-state RF amplifier. Here we review their current development and challenges and offer a perspective from a point of view of operating a light source with high reliability and availability.
	Slides FRXAB01 [4.033 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-FRXAB01
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Paper

Title

Other Keywords

Page

MOYBA02

New Design Approaches for High Intensity Superconducting Linacs – The New ESS Linac Design

cryomodule, linac, cavity, emittance

23

D.P. McGinnis
ESS, Lund, Sweden

The cost of the next generation of high intensity accelerators has become so large that no single institution can solely afford to fund the construction of the project. To fund these large projects, institutions have embarked on forming ambitious collaboration structures with other laboratories. To induce other laboratories to join the collaboration, compromises must be made in the accelerator technical design to offer interesting and challenging projects to partner institutions. The cost of high intensity hadron accelerators is largely driven by RF system. A new design philosophy different from the traditional approach is emerging for the high intensity frontier machines. Emittance preservation is often less of an issue as long as beam losses are kept low. At ESS modifications were introduced to the linac design. One of the major changes is the reduction of final energy and an increase of gradient and beam current. As a result the design now meets the cost objective but for the price of a higher risk. The accelerator system designer must then try to balance the cost and technical risks while also satisfying the interests and external goals of the partner laboratories.

Slides MOYBA02 [2.277 MB]

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MOOCA01

High Power Test Results of the SPARC C-Band Accelerating Structures

controls, accelerating-gradient, vacuum, operation

39

D. Alesini, M. Bellaveglia, M.E. Biagini, R. Boni, P. Chimenti, R. Clementi, G. Di Pirro, R. D. Di Raddo, M. Ferrario, A. Gallo, V.L. Lollo
INFN/LNF, Frascati (Roma), Italy
M. Brönnimann, R. Kalt, T. Schilcher
PSI, Villigen PSI, Switzerland
L. Ficcadenti
INFN-Roma, Roma, Italy
L. Palumbo
URLS, Rome, Italy

The energy upgrade of the SPARC photo-injector at LNF-INFN (Italy) from 150 to more than 240 MeV will be done by replacing a low gradient S-Band accelerating structure with two C-band structures. The structures are Traveling Wave (TW) and Constant Impedance (CI), have symmetric axial input couplers and have been optimized to work with a SLED RF input pulse. In the paper we present the results of the low and high power RF tests on the two final fabricated structures that shown the feasibility of the operation at accelerating gradients larger than 35 MV/m.

Slides MOOCA01 [6.242 MB]

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MOPRO003

Towards Stable Acceleration in Linacs

acceleration, bunching, electron, linac

65

A. Dubrovskiy
Private Address, Geneve, Switzerland

Ultra-stable and -reproducible high-energy particle beams with short bunches are needed in novel linear accelerators and, in particular, in the Compact Linear Collider CLIC. A passive beam phase stabilization system based on a bunch compression with a negative transfer matrix element R56 and acceleration at a positive off-crest phase is proposed. The motivation and expected advantages of the proposed scheme are outlined.

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TUPRI077

Stabilization of Mid-infrared FEL by Feedback Controls

FEL, feedback, electron, gun

1745

H. Zen, M. Inukai, T. Kii, K. Masuda, M. Mishima, H. Negm, H. Ohgaki, K. Okumura, K. Takami, K. Torgasin, Y. Tsugamura, K. Yoshida
Kyoto University, Kyoto, Japan

A Mid-Infrared Free Electron Laser facility, KU-FEL* has been developed for energy related sciences. A beam position monitor and feedback system was introduced to stabilize the FEL output power and wavelength. The long term stability of FEL power and wavelength has been drastically improved by the feedback control. The developed feedback system and its performance will be reported in the conference.
*H. Zen, et al., Infrared Physics & Technology, vol.51, 382-385.

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WEPRO113

Status of the Radiation Source ELBE Upgrade

laser, electron, operation, radiation

2233

P. Michel, T.E. Cowan, U. Lehnert, U. Schramm
HZDR, Dresden, Germany

ELBE is based on a 40 MeV superconducting Electron Linac able to operate in CW mode and provides manifold secondary user beams. The suite of secondary beams include: two free electron lasers operating in the IR/THz regime; a fast neutron beam; a Bremsstrahlung gamma-ray beam; a low-energy positron beam; and patented single-electron test beams. The primary electron beam is also used for radiobiology research, or in interaction with ultra-intense PW-class lasers. Through 2014 ELBE will be upgraded to a Centre for High Power Radiation Sources. The ELBE beam current was increased to 1.6 mA by using novel solid state RF amplifiers. The concept also contains additional broad and narrow band coherent THz sources and the development of a 500 TW TiSa Laser and even a 1.5 PW diode pumped laser system. Laser plasma electron acceleration and proton acceleration experiments for medical applications are planned. Additionally, coupled electron laser beam experiments like Thomson scattering or injection of ELBE electron into the laser plasma will be done.

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WEPME003

Two Years Experience with the Upgraded ELBE RF System Driven by 20kW Solid State Amplifier Blocks (SSPA)

operation, linac, cavity, SRF

2257

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

Since January 2012 the Superconducting CW Linac ELBE is equipped and in permanent operation with four 20 kW Solid State Amplifier Blocks. The poster gives an overview on the design of the new RF system and the experience gained within the first two years of operation.

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WEPME009

Principles for Design of High Power Pulsed Microwave Devices and Devices with Low Operating Voltage for Accelerators

gun, electron, controls, solenoid

2273

K.G. Simonov, A.A. Borisov, I.I. Golenitskiy, A.V. Mamontov, A.N. Yunakov
ISTOK, Moscow Region, Russia
O.A. Morozov
Research and Production Co. "MAGRATEP", Fryazino, Russia

The principle of obtaining the extra-high pulsed power at significantly lower operating voltages by creating klystrons with magnetron gun; location of several such klystrons in a single solenoid with a homogeneous magnetic field and summing their output capacities is proposed. The principle of designing of high-power klystron with multi-beam magnetron gun with anode modulation and several energy outputs is proposed. The principle of designing of high-power klystron magnetron gun with multi-beam magnetron gun with control electrode modulation and several energy outputs is proposed. Are given the results of theoretical studies demonstrating the feasibility of such devices and high-power microwave systems based on them. During development of principles of obtaining an extra-high power were used the design of single-beam klystron with magnetron gun with control electrode modulation created at RPC "Istok".

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WEPME010

Implementation of Single Klystron Working Mode at the ALBA Linac

linac, booster, operation, synchrotron

2276

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

ALBA is a third generation synchrotron light source whose injector consists of a 100 MeV Linac and a Booster that accelerates the beam up to the full energy, 3 GeV. Two pulsed klystrons are used to feed the Linac cavities. Klystron 1 feeds the bunching section and also the first accelerating structure. Klystron 2 feeds exclusively the second accelerating structure. Recently, a S-band switching system installed in the waveguide system allows us to use also Klystron 2 to power the low-energy section and operate the Linac at lower energy, around 65 MeV. So that injection into the Booster is still possible while, in the meantime, Klystron 1 can be connected to a dummy load for reparation. Therefore, the time response after a klystron failure is improved. Details of the waveguide upgrade and the results of the ALBA Linac operated with only one klystron are presented.

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WEPME016

Experience Operating an X-band High-Power Test Stand at CERN

network, controls, vacuum, LLRF

2288

W. Wuensch, N. Catalán Lasheras, A. Degiovanni, S. Döbert, W. Farabolini, J.W. Kovermann, G. McMonagle, S.F. Rey, I. Syratchev, L. Timeo
CERN, Geneva, Switzerland
J. Tagg
National Instruments Switzerland, Ennetbaden, Switzerland
B.J. Woolley
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom

CERN has constructed and is operating a klystron-based X-band test stand, called Xbox-1, dedicated to the high-gradient testing of prototype accelerating structures for CLIC and other applications such as FELs. The test stand has now been in operation for a year and significant progress has been made in understanding the system, improving its reliability, upgrading hardware and implementing automatic algorithms for conditioning the accelerating structures. This experience is reviewed.

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WEPME021

Solid-state Pulsed Klystron Transmitters

high-voltage, operation, power-supply, flattop

2300

K. Schrock, C. Chipman, M.P.J. Gaudreau, B.E. Simpson
Diversified Technologies, Inc., Bedford, Massachusetts, USA

Funding: Lawrence Berkeley National Laboratory Daresbury Laboratory
Diversified Technologies, Inc. (DTI) is currently building and will deliver in early 2014 two solid-state pulsed klystron transmitters. Though not identical, the units are similar in design, and will be delivered to Lawrence Berkeley National Laboratory (LBNL) and Daresbury Laboratory in England. DTI’s goal across these two projects is to develop a complete package which can subsequently be marketed in the high peak power laboratory transmitter market. The modulator is a pulse transformer-coupled hybrid system, including ancillary klystron components (i.e., focus coil, socket) but not the actual klystron tube. Both systems employ a relatively simple modulator, consisting of an energy storage capacitor, a high voltage series switch, a step-up pulse transformer, and a passive pulse-flattening circuit. This arrangement gives an extremely flat pulse and allows the use of a moderate value of storage capacitor. The DTI switch can open or close as commanded, so the pulse width is adjusted by the gate pulse to the system.

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WEPME065

European XFEL RF Gun Commissioning and LLRF Linac Installation

LLRF, gun, linac, cryomodule

2427

J. Branlard, G. Ayvazyan, V. Ayvazyan, L. Butkowski, M.K. Grecki, M. Hoffmann, F. Ludwig, U. Mavrič, S. Pfeiffer, H. Schlarb, Ch. Schmidt, H.C. Weddig, B.Y. Yang
DESY, Hamburg, Germany
S. Bou Habib, K. Czuba, M. Grzegrzółka, E. Janas, J. Piekarski, I. Rutkowski, R. Rybaniec, D. Sikora, L.Z. Zembala, M. Żukociński
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
W. Cichalewski, D.R. Makowski, A. Mielczarek, P. Perek, A. Piotrowski, T. Pożniak
TUL-DMCS, Łódź, Poland
S. Korolczuk, I.M. Kudla, J. Szewiński
NCBJ, Świerk/Otwock, Poland
K. Oliwa, W. Wierba
IFJ-PAN, Kraków, Poland

The European x-ray free electron laser (XFEL) is based on a 17.5 GeV super conducting pulsed linac and is scheduled to deliver its first beam in 2016. The first component of its accelerator chain, the RF gun, was installed in fall of 2013 and its commissioning is underway. This contribution gives an update on the low level radio frequency (LLRF) system development and installation for the XFEL. In particular, the installation, performance and conditioning results of the RF gun are presented. The subsequent steps toward LLRF components mass-production, testing and installation for the XFEL linac are also explained.

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WEPME066

High Speed Digitial LLRF Feedbacks for Normal Conducting Cavity Operation

LLRF, gun, cavity, operation

2430

M. Hoffmann, L. Butkowski, H. Schlarb, Ch. Schmidt
DESY, Hamburg, Germany
W. Köhler
DESY Zeuthen, Zeuthen, Germany
A. Piotrowski
TUL-DMCS, Łódź, Poland
I. Rutkowski, R. Rybaniec
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland

In the first half of the year 2014, the MTCA.4 based LLRF control system will be installed at several facilities (FLASH RF Gun, REGAE, PITZ, FLUTE/KIT). First tests during the last year show promising results in optimizing the system for high speed digital llrf feedbacks (reducing system latency, increase internal controller processing speed). In this contribution we will present further improvements in latency and performance optimization of the system, results and gained experience from the commisioning of the system at the metioned facilities.

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WEPME070

Plans for the Implementation of an Intra-pulse Feedback on the Fermi Linac LLRF System

feedback, LLRF, linac, controls

2441

M. Milloch, A. Fabris, F. Gelmetti, M. Predonzani
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

FERMI is a single-pass linac-based FEL user-facility covering the wavelength range from 100 nm (12 eV) to 4 nm (310 eV) and is located next to the third generation synchrotron radiation facility Elettra in Trieste, Italy. The 1.5 GeV S-band linac is composed of fifteen 3 GHz 45 MW peak RF power plants powering the gun, sixteen accelerating sections and the RF deflectors. The requirements on beam quality impose tight specifications on the stability of the electromagnetic fields that can be achieved only installing high reliable and high performance state of the art LLRF systems. While these requirements are presently met by the system installed, the on-going upgrade of the processing board with the final one will allow to add new functionalities of the system. One of the possible developments is the implementation of an intra-pulse feedback that will allow to apply the corrections inside the RF pulse. This paper provides an overview of the additional benefits that could be achieved and discusses the requirements and the constraints for the implementation in the machine.

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WEPME071

Development and Construction Status of New LLRF Control System for SuperKEKB

controls, cavity, LLRF, FPGA

2444

T. Kobayashi, K. Akai, K. Ebihara, A. Kabe, K. Nakanishi, M. Nishiwaki, J.-I. Odagiri
KEK, Ibaraki, Japan
H. Deguchi, K. Hayashi, T. Iwaki, M. Ryoshi
Mitsubishi Electric TOKKI Systems, Amagasaki, Hyogo, Japan

Beam commissioning of the SuperKEKB will be started in 2015. A new LLRF control system, which is an FPGA-based digital RF feedback control system on the MicroTCA platform, has been developed to satisfy the requirement for high current beam operation of the SuperKEKB. Then final refinements were applied, and now the quantity production is in progress. As a new function, klystron phase lock loop was additionally implemented within the cavity feedback control loop in the FPGA, and it was successfully worked in the low-level operation test. For the SuperKEKB, damping ring (DR) is required for the positron injection. Therefore another new LLRF control system is under development for the DR-RF system. It is operated at the same RF-frequency as the main ring, and vector sum control of three cavities is needed in the DR-LLRF control. In this report, the development status and progress from the previous report will be presented including the RF reference distribution system.

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WEPME078

Experimental Test of the Prototype LLRF Systems for PAL-XFEL

LLRF, target, feedback, impedance

2462

J. Hu, H. Heo, J.H. Hong, W.H. Hwang, H.-S. Kang, H.-S. Lee, C.-K. Min
PAL, Pohang, Kyungbuk, Republic of Korea

Two prototype LLRF systems were developed in collaboration with Pohang Accelerator Laboratory(PAL) and domestic companies. They are focused on the control of single klystron system to obtain mainly analogue performance. The low power test of the developed LLRF showed good performance previously. We experimentally tested LLRF in the klystron systems to see performance in the high power situation. They showed performance around the prototype specification for short time and relatively long time. During test some bugs are discovered and fixed.

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WEPRI072

High Power Co-axial Couplers for SRF Cavities

Windows, SRF, simulation, network

2657

J. Guo, J. Henry, R.A. Rimmer, H. Wang, R.S. Williams
JLab, Newport News, Virginia, USA
A. Dudas, M.L. Neubauer
Muons, Inc, Illinois, USA

Funding: Work supported by Dept. of Energy grant no. DE-SC0002769
High Power RF couplers are required in a wide range of accelerator projects using superconducting RF cavities. We have proposed a novel robust coax SRF coupler design using two pre-stressed disc windows without the need of additional matching elements. The matching frequency and the power handling capacity can be easily scaled by changing the diameter and the spacing of the windows. In this paper, we will present our latest progress in the fabrication and the testing of the windows.

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THPPA02

Gersch Budker Prize Presentation

collider, linear-collider, electron, FEL

2846

T. Shintake
OIST, Onna-son, Okinawa, Japan

SACLA: SPring-8 Angstrom Compact free-electron Laser, previously called XFEL/SPring-8, which is based on electron accelerator technology developed at SCSS project, in which C-band high gradient linear accelerator provides stable driving beams. Looking back upon 20 years R&D on C-band accelerator, I would like to give some advises to young scientists on doing research. The developed C-band accelerator is now providing 8 GeV electron beams at SACLA X-ray FEL in daily operation with the world best energy stability among these large scale machines.

Slides THPPA02 [17.649 MB]

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THPRO019

Current Status of PAL-XFEL Project

undulator, linac, quadrupole, cavity

2897

H.-S. Kang, K.W. Kim, I.S. Ko
PAL, Pohang, Kyungbuk, Republic of Korea

The PAL-XFEL, a 0.1-nm hard X-ray FEL facility consisting of a 10-GeV S-band linac, is being constructed in Pohang, South Korea. The installation of linac, undulator, and beam line will be completed by 2015. Its building construction is at its peak moment to be completed by December 2014. The major procurement contract was made in 2013 for the critical components of S-band linac modules and hard X-ray undulators. The commissioning will start in January 2016. We hope the first lasing will be achieved in early 2016.

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THPRO021

Results Produced after Measuring PAL-ITF Beam Diagnostic Instruments

pick-up, diagnostics, controls, laser

2903

H. J. Choi, M.S. Chae, J.H. Hong, H.-S. Kang, S.J. Park
PAL, Pohang, Kyungbuk, Republic of Korea

Pohang Accelerator Laboratory (PAL) built a PAL-ITF at the end of 2012 to successfully complete PAL-XFEL in 2015. The PAL-ITF is equipped with various kinds of diagnostic equipment to produce high-quality electron bunches. An ICT and a Turbo-ICT were installed in the PAL-ITF. A Faraday Cup is installed at the end of the linear accelerator. These days, the quantity of electric charge occasionally is measured using a BPM Sum value. This paper focuses on the processes and results of electric charge quantity measurements using ICT, Turbo-ICT, FC and BPM. The PAL-ITF is equipped with Stripline-BPM. It is important to find a way to minimize measurement errors that can appear in the process of installing or measuring the BPM. For this, PAL-ITF separately measured the BPM electrode sensitivity and minimized BPM measurement errors through generally calibrating BPM devices by applying Lambertson's Method. A plan was made to minimize BPM measurement errors through applying the BPM electrical calibration method for BPM devices to be used by the PAL-XFEL. This paper examines the processes for checking the performance of the S-BPM installed in the PAL-ITF and the results of its measurements.

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THPRO025

Conceptual Design of a X-FEL Facility using CLIC X-band Accelerating Structure

linac, FEL, simulation, gun

2914

A.A. Aksoy, O. Yavaş
Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey
D. Angal-Kalinin, J.A. Clarke
Cockcroft Institute, Warrington, Cheshire, United Kingdom
M.J. Boland
SLSA, Clayton, Australia
G. D'Auria, S. Di Mitri, C. Serpico
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
M. Doğan
Dogus University, Istanbul, Turkey
T.J.C. Ekelöf, R.J.M.Y. Ruber, V.G. Ziemann
Uppsala University, Uppsala, Sweden
W. Fang, Q. Gu
SINAP, Shanghai, People's Republic of China
A. Latina, D. Schulte, S. Stapnes, I. Syratchev, W. Wuensch
CERN, Geneva, Switzerland
Z. Nergiz
Nigde University, Nigde University Science & Art Faculty, Nigde, Turkey

Within last decade a linear accelerating structure with an average loaded gradient of 100 MV/m at 12 GHz has been demonstrated in the CLIC study. Recently, it has been proposed to use the CLIC structure to drive an FEL linac. In contrast to CLIC the linac would be powered by klystrons not by a drive beam. The main advantage of this proposal is achieving the required energies in a very short distance, thus the facility would be rather compact. In this study, we present the conceptual design parameters of a facility which could generate laser photon pulses covering the range of 1-75 Angstrom. Shorter wavelengths could also be reached with slightly increasing the energy.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO025

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THPME171

General-purpose Spectrometer for Vacuum Breakdown Diagnostics for the 12 GHz Test Stand at CERN

electron, vacuum, simulation, diagnostics

3668

M. Jacewicz, Ch. Borgmann, J. Ögren, R.J.M.Y. Ruber, V.G. Ziemann
Uppsala University, Uppsala, Sweden

Funding: This work is supported by the grants from the the Swedish Research Council DNR-2011-6305 and DNR-2009-6234.
We discuss a spectrometer to analyze the electrons and ions ejected from a high-gradient CLIC accelerating structure that is installed in the klystron-driven 12 GHz test-stand at CERN. The charged particles escaping the structure provide useful information about the physics of the vacuum breakdown within a single RF pulse. The spectrometer consists of a dipole magnet, a pepper-pot collimator, a fluorescent screen and a fast camera. This enables us to detect both transverse parameters such as the emittance and longitudinal parameters such as the energy distribution of the ejected beams. We can correlate these measurements with e.g. the location of the breakdown inside the structure, by using information from the measured RF powers, giving in that way a complete picture of the vacuum breakdown phenomenon. The spectrometer was installed during Spring 2014 and will be commissioned during Summer 2014.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME171

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THPRI031

Design and Commissioning of S-Band RF Station for AREAL Test Facility

gun, electron, LLRF, operation

3834

A. Vardanyan, H. Avdishyan, H. Davtyan, B. Grigoryan, L.H. Hakobyan, H. Poladyan
CANDLE SRI, Yerevan, Armenia

The RF station has been designed and constructed for AREAL Linac. The constructional features and commissioning results of RF system are presented. The whole RF system is designed to work at 3GHz frequency. The linac includes an electron gun for 0.5-8 ps electron bunch production with 1-10 Hz repetition rate. For linac RF control system a Libera LLRF stabilization system is used. An important feature of the presented system is a high level synchronization of amplitude-phase characteristics which provide the required accuracy for particle acceleration and bunch formation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI031

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THPRI041

Twenty Years of Operation of the Elettra RF System

operation, cavity, storage-ring, booster

3853

C. P. Pasotti, M. Bocciai, P. Pittana, M. Rinaldi
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

Six thousand hours per year is the typical running scheduled time of the user-dedicated Elettra facility and twenty years is a significant amount of operating hours for the RF system. Failure and weak points of the installed equipment is discussed as well as the up-time statistic. The effectiveness of the predictive versus the extraordinary maintenance is presented. The gained operational experience has allowed the planning of the priorities to refit the installed components within a reasonable budget, in compliance with the user-operation time schedule and following the technical need of upgrading to improve the RF system performance.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI041

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THPRI044

Vacuum Waveguide System for SPring-8 Linac Injector Section

vacuum, linac, electron, operation

3863

T. Taniuchi, H. Dewa, H. Hanaki, T. Kobayashi, T. Magome, A. Mizuno, S. Suzuki, K. Yanagida
JASRI/SPring-8, Hyogo-ken, Japan

An SF6 waveguide system for the injector section of SPring-8 linac has been replaced in a vacuum waveguide system including a newly developed vacuum circulator and an isolator. This paper describes developed RF components, a waveguide configuration and an RF conditioning of the system.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI044

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THPRI058

RF Delivery System for FETS

rfq, rf-amplifier, quadrupole, simulation

3902

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

The Front End Test Stand (FETS) is an experiment based at the Rutherford Appleton Laboratory (RAL) in the UK. In this experiment, the first stages necessary to produce a very high quality, chopped H⁻ ion beam as required for the next generation of high power proton accelerators (HPPAs) are designed, built and tested. HPPAs with beam powers in the megawatt range have many possible applications including drivers for spallation neutron sources, neutrino factories, accelerator driven sub-critical systems, waste transmuters and tritium production facilities. An RF system outline, circulator high power tests, RF amplifiers tests, waveguide run with shielding and couplers design are presented and discussed in this paper. Experimental measurements of the system’s circulator and RF Amplifiers high power test will be presented as part of the system testing results.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI058

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THPRI078

Experimental Study of Surface RF Magnetic Field Enhancement Caused by Closely Spaced Protrusions

cavity, vacuum, superconductivity, experiment

3949

F.Y. Wang, C. Adolphsen, J.P. Eichner, C.D. Nantista, L. Xiao
SLAC, Menlo Park, California, USA

The RF magnetic field enhancement between two closely spaced protrusions on a metallic surface has been studied theoretically. It is found that a large enhancement occurs when the field is perpendicular to the gap between the protrusions. This mechanism could help explain the melting that has been observed on cavity surfaces subjected to pulsed heating that would nominally be well below the melting temperature of the surface material. To test this possibility, an experiment was carried out in which a pair of copper “pins” was attached to the base plate of an X-band cavity normally used to study pulsed heating. Melting was observed between the pins when the predicted peak temperature was near or exceeded the copper melting temperature.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI078

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THPRI079

RF BREAKDOWN IN A GAS-FILLED TE01 CAVITY

cavity, plasma, electron, simulation

3952

F.Y. Wang, C. Adolphsen, C.D. Nantista
SLAC, Menlo Park, California, USA

An L-band (1.3 GHz) TE01 mode pillbox cavity has been designed to study rf breakdown in gas. Since there are no surface electric fields, effects from the electron interaction with the surface should not be present as in the DC breakdown case. A CCD camera was used to measure the integrated light pattern through holes in the cavity, and an ultrafast diode was used to observed the evolution of the plasma during breakdown. Some preliminary results of the tests are presented in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI079

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THPRI100

Distributed Cooling System for the AREAL Test Facility

gun, electron, operation, controls

4010

V. V. Vardanyan, G.A. Amatuni, V.S. Avagyan, A.A. Gevorgyan, B. Grigoryan, T.H. Mkrtchyan, V. Sahakyan, A.S. Simonyan, A.V. Tsakanian, A. Vardanyan
CANDLE SRI, Yerevan, Armenia

Following the design specifications of the Advanced Research Electron Accelerator Laboratory (AREAL), a reliable distributed cooling system for the AREAL linear accelerator has been developed. The cooling system provides a high accuracy temperature control for the electron gun, klystron and the magnets. The main requirements and technical solutions for various accelerator components cooling units are presented, including the local and remote control.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI100

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FRXAB01

Trends in RF Technology for Applications to Light Sources with Great Average Power

operation, rf-amplifier, high-voltage, power-supply

4065

Ch. Wang
NSRRC, Hsinchu, Taiwan

RF systems are a major part of both the capital and operating costs of contemporary light sources and directly impact their capability, reliability and availability. The RF community has been discussing for many years the best choice of CW RF power source for light sources. In the domain of great average power, the choice is among a klystron, inductive-output tube, and solid-state RF amplifier. Here we review their current development and challenges and offer a perspective from a point of view of operating a light source with high reliability and availability.

Slides FRXAB01 [4.033 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-FRXAB01

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