LINAC2018 - List of Keywords (coupling)

Paper	Title	Other Keywords	Page
MOPO026	The Resonance Frequency Shift After Applying the Cooling System for a Side Coupled Standing Wave Linac	cavity, controls, electron, radio-frequency	81
	M. Mohseni Kejani, F. Abbasi Davani Shahid Beheshti University, Tehran, Iran S. Ahmadiannamin ILSF, Tehran, Iran F. Ghasemi NSTRI, Tehran, Iran S. Zarei Nuclear Science and Technology Research, InstituteRadiation Application School, Tehran, Iran
	A radio frequency accelerator tube used in linear medical accelerators includes three main sections of the radio frequency cavity, an electron gun and the X-ray target, which is vacuumed by a pump inside it. The electromagnetic energy loss in the structure of the cavity can increase the temperature of the tube, resulting in changes in the geometric dimensions and then changes in some of the cavity characteristics, such as the resonance frequency. A cooling system is required to prevent excessive change in the resonant frequency due to thermal loss. Also, it is necessary to perform some computer simulations to stabilize the cavity’s performance in the presence of electromagnetic energy thermal dissipation and the cooling system. In this paper, the simulation results of resonant frequency shifts after applying the cooling system have been reported.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO026
About •	paper received ※ 12 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019
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MOPO039	Status Update of the Fast Energy Corrector Cavity at FLASH	cavity, electron, laser, free-electron-laser	112
	S. Pfeiffer, J. Branlard, L. Butkowski, M. Hierholzer, M. Hoffmann, K. Honkavaara, H. Schlarb, Ch. Schmidt, S. Schreiber, M. Vogt, J. Zemella DESY, Hamburg, Germany M. Fakhari CFEL, Hamburg, Germany
	Funding: The work is part of EuCARD-2, partly funded by the European Commission, GA 312453. Linear accelerator facilities driving a free-electron laser require femtosecond precision synchronization between external laser systems and the electron beam. Such high precision is required for pump-probe experiments and also for example for the electron bunch injection into a plasma bubble for laser plasma acceleration. An upgrade of the fast intra-train beam-based feedback system is planned at the Free-Electron Laser FLASH in Hamburg, Germany. This linear accelerator is based on superconducting (SRF) technology operating with pulse trains of maximum 1 MHz bunch repetition rate. Arrival time fluctuations of the electron beam are correctable by introducing small energy modulations prior to the magnetic bunch compressor. This contribution focuses on the design and the characterization of a normal-conducting RF (NRF) cavity with large bandwidth, mandatory to correct fast arrival time fluctuations. The cavity has recently been installed in the FLASH beamline. First measurements with the new cavity will be presented.
	Poster MOPO039 [1.884 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO039
About •	paper received ※ 13 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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MOPO066	Simulation of the Transitional Process in Accelerating Sections by Equivalent Circuit Method	operation, simulation, MMI, interface	145
	S.V. Matsievskiy, V.I. Kaminskiy, Ya.V. Shashkov MEPhI, Moscow, Russia
	Nowadays linac accelerating RF systems design is usually done by the finite difference method. It provides high accuracy of calculations and freedom in topology choosing, but may draw considerable amounts of computer resources with long calculation times. Alternative to this method, equivalent circuit method exists. The basic idea of this method is to build a lumped element circuit, which with certain approximation acts as an original accelerating cell. It drastically reduces the number of equations to solve. This method is long known but usually only used for the particular accelerating structures when speed of calculation is a key-factor. Present paper describes a way to numerically simulate transition processes in arbitrary coupled accelerating cells using the equivalent circuit method. This approach allows simulating transitional processes in accelerating structures significantly faster and allows doing so for structures with high quality factor and many cells - a hard task for conventional transient solvers based on the finite difference method.
	Poster MOPO066 [0.519 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO066
About •	paper received ※ 23 August 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019
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MOPO070	Construction of the Side-coupled Standing-wave e-Linac	cavity, simulation, linac, electron	151
	S. Zarei Nuclear Science and Technology Research, InstituteRadiation Application School, Tehran, Iran F. Abbasi Shahid Beheshti University, Tehran, Iran M. Bahrami, M. Lamehi IPM, Tehran, Iran F. Ghasemi NSTRI, Tehran, Iran
	Due to Iran’s growing need for accelerators in various applications, NSTRI electron linear accelerator project has been defined for medical and inspection applications. This accelerator is a 6 MeV side-coupled standing-wave that operate is π /2 mode in the frequency of 2998.5 MHz. In this paper the construction and measurement results of the tube of this accelerator are presented. The prototype tube was constructed from aluminum and was clamped with bolts. By using a network analyzer, electric and magnetic probes and a side-coupled cavity tuning method and a bead-pull measurement technique, RF measurements were carried out. The resonant frequency and quality factor have been achieved 2998.5 MHz and 7940 respectively . low-energy accelerator, construction of linac, standing-wave linac
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO070
About •	paper received ※ 12 September 2018 paper accepted ※ 09 November 2018 issue date ※ 18 January 2019
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MOPO077	Design of the High Gradient Negative Harmonic Structure for Compact Ion Therapy Linac	linac, proton, operation, simulation	160
	S.V. Kutsaev, R.B. Agustsson, A.Yu. Smirnov, A. Verma RadiaBeam, Santa Monica, California, USA A. Barcikowski, R.L. Fischer, B. Mustapha ANL, Argonne, Illinois, USA
	Funding: This work was supported by the U.S. Department of Energy, Office of High Energy Physics, under SBIR grant DE-SC0015717 and Accelerator Stewardship Grant, Proposal No. 0000219678 A novel concept for an Advanced Compact Carbon Ion Linac (ACCIL) that will deliver up to 1 pnA of carbon ions with variable energy from 45 MeV/u to 450 MeV/u in a 45 m footprint, has been developed by Argonne National Laboratory (ANL) in collaboration with RadiaBeam. The ACCIL will have a 35 MV/m real-estate accelerating gradients that became possible to achieve with the development of novel S-band high-gradient structures, capable of providing 50 MV/m accelerating gradients for particles with β>0.3. In particular, a β=0.3 structure based on the novel approach of operation at the first negative spatial harmonic with the increased distance between the accelerating gaps will be presented. This is the first attempt to reach such high gradients at such small velocities. RadiaBeam and ANL have demonstrated the feasibility of building this structure for accelerating carbon ions by means of advanced computer simulations and are currently working towards the fabrication of this structure for high power tests.
	Slides MOPO077 [1.863 MB]
	Poster MOPO077 [0.923 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO077
About •	paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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MOPO119	Design of a Fully Automated Test Bench for Measuring the Field Distribution in Standing Wave Cavity	cavity, simulation, controls, network	246
	Y. Lu, G. Feng, T. Hu, J. Jiang, X.D. Tu, Y.Q. Xiong HUST, Wuhan, People’s Republic of China
	The resonant cavity plays a great role in the linear accelerator. An accurate measurement of the cavity field distribution is very important to design linear accelerators. A fully computer controlled bench for the electric field distribution has been developed in this context. Based on the perturbation theory, the acquisition of the resonant frequency shift is proportional to the square of E (electric field). In order to verify the reliability of the test bench, a standard cylindrical cavity has been tested in this measurement system. The simulation by HFSS (High Frequency Structure Simulator) and the practice will be both presented in this paper. And the result demonstrates that, because of its high concentricity, the automated test bench achieves high precision in measuring the distribution of electric field.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO119
About •	paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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MOPO124	Details of the Manufacturing Processes of the ESS-DTL Components	DTL, alignment, vacuum, linac	260
	P. Mereu, F. Borotto Dalla Vecchia, C. Mingioni, M. Nenni, R. Panero INFN-Torino, Torino, Italy A. Battistello, P. Bottin, D. Conventi, L. Ferrari, F. Grespan, A. Pisent INFN/LNL, Legnaro (PD), Italy A.G. Colombo INFN- Sez. di Padova, Padova, Italy
	The Drift Tube Linac (DTL) of the European Spallation Source (ESS) is designed to operate at 352.2MHz with a duty cycle of 4% (3 ms pulse length, 14 Hz repetition period) and will accelerate a proton beam of 62.5mA pulse peak current from 3.62 to 90 MeV. This paper presents the details of the manufacturing processes with quality control reports of the components of the DTL.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO124
About •	paper received ※ 12 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019
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TUPO045	Optimization of Dual Axis Asymmetric Cavity for Energy Recovery Linac	cavity, linac, HOM, SRF	435
	Ya.V. Shashkov, A.M. Bulygin, M. Gusarova MEPhI, Moscow, Russia I.V. Konoplev JAI, Oxford, United Kingdom F. Marhauser JLab, Newport News, Virginia, USA A. Seryi SLAC, Menlo Park, California, USA
	Funding: The reported study was funded by RFBR according to the research project № 18-302-00990 Optimization of the dual axis asymmetric cavity was performed to minimize the ratio of the peak magnetic and electric fields values to the accelerating voltage, to increase the distance between operating and neighbouring modes as well as to reduce the manufacturing cost of the cavity. To reach the goals several solutions have been suggested bringing the ratios to the acceptable values and leading to simplification of the manufacturing of the structure.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO045
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO003	L-band Resonant Ring for Testing RF Windows for ILC	collider, simulation, klystron, linear-collider	679
	B. Du, N. Liu Sokendai - Hayama, Hayama, Japan T. Matsumoto, S. Michizono, T. Miura, F. Qiu KEK, Ibaraki, Japan T. Matsumoto, T. Miura, F. Qiu Sokendai, Ibaraki, Japan
	A resonant ring is widely used for the breakdown test of RF components under high power. It can reach power gain of more than 10dB, which is limited by the attenua-tion of the ring. An L-band resonant ring is constructed for testing RF components of International Linear Collid-er (ILC) which is based on an RF frequency of 1.3GHz. The target of the high power test is 5 MW. We have fin-ished the test of an input power of 500 W using a solid state amplifier, and the principle of the resonant ring is verified. The resonant ring is tuned to an optimal condi-tion, which is preparation for high power operation. This paper details the principle, construction, and test of the L-band resonant ring.
	Poster THPO003 [2.301 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO003
About •	paper received ※ 13 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
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THPO038	Status of the Power Couplers for the CSNS DTL	DTL, cavity, vacuum, operation	767
	M.X. Fan, A.H. Li, B. Li, P.H. Qu, Y. Wang, X.L. Wu CSNS, Guangdong Province, People’s Republic of China Q. Chen, K.Y. Gong, H.C. Liu IHEP, Beijing, People’s Republic of China
	There are four Drift Tube Linac (DTL) tanks in China Spallation Neutron Source (CSNS) Project. Each DTL tank requires a power coupler with a peak power of 2 MW and a duty cycle of 1.5% for beam operation. After approximately two years machining, all four couplers were already installed in the tunnel before year 2017. Up to now, the first phase of beam tuning has been completed, the maximum transmission power of the coupler exceeds 1.7 MW with a pulse width of 650 μs and a repetition rate of 25 Hz, meanwhile, the vacuum is maintained on the order of 10^-6 Pa during the operation and no breakdown was observed. This paper describes the architecture, the fabrication, the low power test results and the high power conditioning process of the coupler. Some problems encountered are also presented. This work was supported by Youth Innovation Promotion Association of CAS (2015011)
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO038
About •	paper received ※ 30 August 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO060	First RF Measurements of the 325 MHz Ladder RFQ	rfq, linac, simulation, proton	826
	M. Schuett, U. Ratzinger, M. Syha IAP, Frankfurt am Main, Germany
	Funding: BMBF 05P15RFRBA Based on the positive results of the unmodulated 325 MHz Ladder-RFQ prototype from 2013 to 2016, we developed and designed a modulated 3.3 m Ladder-RFQ. The unmodulated prototype Ladder-RFQ features a very constant voltage along the axis. The RFQ was high power tested at the GSI test stand. It accepted 3 times the RF power level needed in operation. That level corresponds to a Kilpatrick factor of 3.1 with a pulse length of 200 µs. The 325 MHz RFQ is designed to accelerate protons from 95 keV to 3.0 MeV according to the design parameters of the proton linac within the FAIR project. This particular high frequency creates difficulties for a 4-ROD type RFQ, which triggered the development of a Ladder RFQ with its higher symmetry. The results of the unmodulated prototype have shown, that the Ladder-RFQ is a suitable candidate for that frequency. For the present design duty cycles are feasible up to 5%. The basic design and tendering of the RFQ has been successfully completed in 2016. Manufacturing will be completed in August 2018. We will show the the finalization of manufacturing as well as first low level RF measurements of the Ladder RFQ. Journal of Physics: Conf. Series 874 (2017) 012048 **Proceedings of LINAC2016, East Lansing, TUPLR053
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO060
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO064	Tuning of a Four-vane RFQ for Xi’an 200 MeV Proton Application Facility	rfq, dipole, quadrupole, cavity	838
	X.D. Yu, X. Guan, Q.K. Guo, Y. Lei, P.F. Ma, X.W. Wang, Q.Z. Xing, S.X. Zheng TUB, Beijing, People’s Republic of China B.C. Wang, Z.M. Wang, C. Zhao NINT, Shannxi, People’s Republic of China
	This paper mainly describes the procedures and results of tuning a four-vane Radio Frequency Quadrupole (RFQ) accelerator for the Xi’an 200 MeV Proton Application Facility (XiPAF) project. The 3-meter-long RFQ will accelerate a 50 keV H⁻ beam from the ECR source to 3 MeV, and deliver it to the downstream drift tube linac (DTL) with a peak current of 5 mA, pulse length of 10-40 μs and maximum repetition rate of 0.5. The machining, assembly, and RF tuning of the RFQ cavity has been completed successfully. After tuning, the relative error of the operating quadrupole mode field is within ±2.7%, and the dipole mode com-ponent is within ±1.9% of the quadrupole mode. The RFQ now is ready for high-power RF conditioning.
	Poster THPO064 [1.413 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO064
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO082	Physical Design of a Rectangular RF Deflector for Ultrashort Bunch Length Measurement	cavity, electron, simulation, FEL	872
	J. Bai, Q.S. Chen, K. Fan HUST, Wuhan, People’s Republic of China
	Cylindrical deflectors which are now widely used for bunch length measurement suffer from the degeneration of polarization, while rectangular deflectors can separate polarization mode easily. This paper is focused on the study of a one-cell rectangular deflector, which is considerably different from cylindrical structure or multi-cell structure. A one-cell structure is free of π mode restriction and can achieve higher deflection efficiency per unit length. The proposed scheme is expected to achieve time resolution better than 200fs with the driving power less than 1MW. Cavity optimization and beam dynamic simulation are introduced in this paper.
	Poster THPO082 [0.484 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO082
About •	paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO100	Development of a 1.5 GHz High-power CW Magnetron for SRF Accelerator	simulation, cavity, electron, SRF	908
	L. Wenliang College of Engineering and Applied Sciences for Nanjing University, Nanjing, People’s Republic of China S. An, Y.J. Ke, S. Lingbin, Z. Pengjiao, L. Youchun, L. Zhao, B.Z. Zhou PLAI, Nanjing, People’s Republic of China J.Z. Li, L.P. Zhang, Hou, R. Rui ADS, Jiangsu Province, People’s Republic of China
	An 1.5 GHz, 13.5 kW CW high-power magnetron for a superconducting RF accelerator has been developed by Andesun Technology Group Co., Ltd. with Nanjing Sanle Electronic Information Industry Group Co., Ltd., in order to replace the klystron, that could reduce the power source cost to about one-third. The cavity, output power antenna and coupling door-nob have been optimized by using CST Studio. Testing results have shown that the resonance frequency and output power have met the requirements, and the efficiency of the magnetron is higher that 78.45%.
	Poster THPO100 [0.574 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO100
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO104	Development of 150.4MHz Continuous Wave Solid-state Amplifier	power-supply, controls, insertion, radiation	917
	L. Zhao Nanjing University of Aeronautics and Astronautics, Jiangning, People’s Republic of China S. An, Y.J. Ke, Z. Pengjiao, L. Wenliang, B.Z. Zhou PLAI, Nanjing, People’s Republic of China
	A 150.4MHz to 155.4MHz, 300W continuous wave solid-state amplifier as an accelerator power source has been developed by us. In order to increase the lifetime of MOSFET and meet the requirements of every parameters, Drain voltage and quiescent current is set at a better point with a well-designed heat dissipation structure, we make the solid state amplifier stable in performance. Taking the microwave leakage into account, the chassis structure is optimized and designed, and the microwave absorption device is adopted to make the structure compact, protect other parts not affected by the microwave leakage. After the assembly is completed, the working parameters meet the design requirements very well. The MOSFET flange temperature and output parameters meet the design requirements.
	Poster THPO104 [1.405 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO104
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO108	Development of an High Gradient Side Coupled Cavity for PROBE	cavity, proton, linac, target	924
	S. Pitman, R. Apsimon, G. Burt Cockcroft Institute, Lancaster University, Lancaster, United Kingdom N. Catalán Lasheras, A. Grudiev, W. Wuensch CERN, Geneva, Switzerland H.L. Owen UMAN, Manchester, United Kingdom
	The PROBE project aims to develop a high gradient proton accelerator for protons with energy around 250-350 MeV for proton radiography. Detailed studies have shown that the optimum design is a side coupled cavity at S-band. With an aperture of 8 mm a gradient of 54 MV/m can be obtained with 13 MW of RF power in a 30 cm structure. A prototype cavity has been machined by VDL and diffusion bonded by Bodycote. We present initial measurements of the prototype.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO108
About •	paper received ※ 17 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
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THPO109	A New Spherical Pulse Compressor Working with Degenerated "Whispering Gallery" Mode	cavity, GUI, simulation, collider	928
	Z.B. Li, W. Fang, Q. Gu, Z.T. Zhao SINAP, Shanghai, People’s Republic of China A. Grudiev CERN, Geneva, Switzerland
	CLIC is focusing on the Compact Linear Collider. To obtain a relatively high accelerating gradient, CLIC utilizes Pulse Compressors to increase the input power of accelerators. This work is to make an alternative design for CLIC pulse compression scheme. There are several kinds of pulse compressor: SLED, BOC, SLED-Ⅱ, spherical pulse compressor and so on. Usually, a spherical cavity, including BOC, can offer a higher Q factor compared with a cylindrical cavity. This design utilizes a spherical cavity working with degenerated Whispering Gallery mode.
	Slides THPO109 [1.738 MB]
	Poster THPO109 [1.913 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO109
About •	paper received ※ 11 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
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THPO118	Beam Transverse Coupling and 4D Emittance Measurement Simulation Studies for PITZ	emittance, quadrupole, simulation, gun	945
	Q.T. Zhao, M. Krasilnikov, H.J. Qian, F. Stephan DESY Zeuthen, Zeuthen, Germany Q.T. Zhao IMP/CAS, Lanzhou, People’s Republic of China
	The Photo Injector Test Facility at DESY, Zeuthen site (PITZ) was built to test and optimize high brightness electron sources for Free Electron Lasers (FELs) like FLASH and the European XFEL. Although the beam emittance has been optimized and experimentally demonstrated to meet the requirements of FLASH and XFEL, transverse beam asymmetries were observed during operation of the RF guns. Based on previous studies [1], the beam asymmetries most probably stem from beam transverse coupling by quadrupole field errors in the gun section. A pair of normal and skew gun quadrupoles was successfully used for reducing the beam asymmetries in experiment. In this paper, we discuss the beam transverse coupling between X and Y planes due to quadrupole field errors and its impact onto horizontal and vertical rms emittance. Multi-quads scan and two quads with rotated slits scan were proposed to measure the 4D beam matrix for PITZ and tested by simulation, which will give the residual beam coupling after gun quadrupoles compensation and would be helpful for minimizing the 2D rms emittance experimentally.
	Poster THPO118 [1.521 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO118
About •	paper received ※ 08 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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Paper

Title

Other Keywords

Page

MOPO026

The Resonance Frequency Shift After Applying the Cooling System for a Side Coupled Standing Wave Linac

cavity, controls, electron, radio-frequency

81

M. Mohseni Kejani, F. Abbasi Davani
Shahid Beheshti University, Tehran, Iran
S. Ahmadiannamin
ILSF, Tehran, Iran
F. Ghasemi
NSTRI, Tehran, Iran
S. Zarei
Nuclear Science and Technology Research, InstituteRadiation Application School, Tehran, Iran

A radio frequency accelerator tube used in linear medical accelerators includes three main sections of the radio frequency cavity, an electron gun and the X-ray target, which is vacuumed by a pump inside it. The electromagnetic energy loss in the structure of the cavity can increase the temperature of the tube, resulting in changes in the geometric dimensions and then changes in some of the cavity characteristics, such as the resonance frequency. A cooling system is required to prevent excessive change in the resonant frequency due to thermal loss. Also, it is necessary to perform some computer simulations to stabilize the cavity’s performance in the presence of electromagnetic energy thermal dissipation and the cooling system. In this paper, the simulation results of resonant frequency shifts after applying the cooling system have been reported.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO026

About •

paper received ※ 12 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019

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MOPO039

Status Update of the Fast Energy Corrector Cavity at FLASH

cavity, electron, laser, free-electron-laser

112

S. Pfeiffer, J. Branlard, L. Butkowski, M. Hierholzer, M. Hoffmann, K. Honkavaara, H. Schlarb, Ch. Schmidt, S. Schreiber, M. Vogt, J. Zemella
DESY, Hamburg, Germany
M. Fakhari
CFEL, Hamburg, Germany

Funding: The work is part of EuCARD-2, partly funded by the European Commission, GA 312453.
Linear accelerator facilities driving a free-electron laser require femtosecond precision synchronization between external laser systems and the electron beam. Such high precision is required for pump-probe experiments and also for example for the electron bunch injection into a plasma bubble for laser plasma acceleration. An upgrade of the fast intra-train beam-based feedback system is planned at the Free-Electron Laser FLASH in Hamburg, Germany. This linear accelerator is based on superconducting (SRF) technology operating with pulse trains of maximum 1 MHz bunch repetition rate. Arrival time fluctuations of the electron beam are correctable by introducing small energy modulations prior to the magnetic bunch compressor. This contribution focuses on the design and the characterization of a normal-conducting RF (NRF) cavity with large bandwidth, mandatory to correct fast arrival time fluctuations. The cavity has recently been installed in the FLASH beamline. First measurements with the new cavity will be presented.

Poster MOPO039 [1.884 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO039

About •

paper received ※ 13 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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MOPO066

Simulation of the Transitional Process in Accelerating Sections by Equivalent Circuit Method

operation, simulation, MMI, interface

145

S.V. Matsievskiy, V.I. Kaminskiy, Ya.V. Shashkov
MEPhI, Moscow, Russia

Nowadays linac accelerating RF systems design is usually done by the finite difference method. It provides high accuracy of calculations and freedom in topology choosing, but may draw considerable amounts of computer resources with long calculation times. Alternative to this method, equivalent circuit method exists. The basic idea of this method is to build a lumped element circuit, which with certain approximation acts as an original accelerating cell. It drastically reduces the number of equations to solve. This method is long known but usually only used for the particular accelerating structures when speed of calculation is a key-factor. Present paper describes a way to numerically simulate transition processes in arbitrary coupled accelerating cells using the equivalent circuit method. This approach allows simulating transitional processes in accelerating structures significantly faster and allows doing so for structures with high quality factor and many cells - a hard task for conventional transient solvers based on the finite difference method.

Poster MOPO066 [0.519 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO066

About •

paper received ※ 23 August 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019

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MOPO070

Construction of the Side-coupled Standing-wave e-Linac

cavity, simulation, linac, electron

151

S. Zarei
Nuclear Science and Technology Research, InstituteRadiation Application School, Tehran, Iran
F. Abbasi
Shahid Beheshti University, Tehran, Iran
M. Bahrami, M. Lamehi
IPM, Tehran, Iran
F. Ghasemi
NSTRI, Tehran, Iran

Due to Iran’s growing need for accelerators in various applications, NSTRI electron linear accelerator project has been defined for medical and inspection applications. This accelerator is a 6 MeV side-coupled standing-wave that operate is π /2 mode in the frequency of 2998.5 MHz. In this paper the construction and measurement results of the tube of this accelerator are presented. The prototype tube was constructed from aluminum and was clamped with bolts. By using a network analyzer, electric and magnetic probes and a side-coupled cavity tuning method and a bead-pull measurement technique, RF measurements were carried out. The resonant frequency and quality factor have been achieved 2998.5 MHz and 7940 respectively .
low-energy accelerator, construction of linac, standing-wave linac

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO070

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paper received ※ 12 September 2018 paper accepted ※ 09 November 2018 issue date ※ 18 January 2019

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MOPO077

Design of the High Gradient Negative Harmonic Structure for Compact Ion Therapy Linac

linac, proton, operation, simulation

160

S.V. Kutsaev, R.B. Agustsson, A.Yu. Smirnov, A. Verma
RadiaBeam, Santa Monica, California, USA
A. Barcikowski, R.L. Fischer, B. Mustapha
ANL, Argonne, Illinois, USA

Funding: This work was supported by the U.S. Department of Energy, Office of High Energy Physics, under SBIR grant DE-SC0015717 and Accelerator Stewardship Grant, Proposal No. 0000219678
A novel concept for an Advanced Compact Carbon Ion Linac (ACCIL) that will deliver up to 1 pnA of carbon ions with variable energy from 45 MeV/u to 450 MeV/u in a 45 m footprint, has been developed by Argonne National Laboratory (ANL) in collaboration with RadiaBeam. The ACCIL will have a 35 MV/m real-estate accelerating gradients that became possible to achieve with the development of novel S-band high-gradient structures, capable of providing 50 MV/m accelerating gradients for particles with β>0.3. In particular, a β=0.3 structure based on the novel approach of operation at the first negative spatial harmonic with the increased distance between the accelerating gaps will be presented. This is the first attempt to reach such high gradients at such small velocities. RadiaBeam and ANL have demonstrated the feasibility of building this structure for accelerating carbon ions by means of advanced computer simulations and are currently working towards the fabrication of this structure for high power tests.

Slides MOPO077 [1.863 MB]

Poster MOPO077 [0.923 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO077

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paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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MOPO119

Design of a Fully Automated Test Bench for Measuring the Field Distribution in Standing Wave Cavity

cavity, simulation, controls, network

246

Y. Lu, G. Feng, T. Hu, J. Jiang, X.D. Tu, Y.Q. Xiong
HUST, Wuhan, People’s Republic of China

The resonant cavity plays a great role in the linear accelerator. An accurate measurement of the cavity field distribution is very important to design linear accelerators. A fully computer controlled bench for the electric field distribution has been developed in this context. Based on the perturbation theory, the acquisition of the resonant frequency shift is proportional to the square of E (electric field). In order to verify the reliability of the test bench, a standard cylindrical cavity has been tested in this measurement system. The simulation by HFSS (High Frequency Structure Simulator) and the practice will be both presented in this paper. And the result demonstrates that, because of its high concentricity, the automated test bench achieves high precision in measuring the distribution of electric field.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO119

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paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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MOPO124

Details of the Manufacturing Processes of the ESS-DTL Components

DTL, alignment, vacuum, linac

260

P. Mereu, F. Borotto Dalla Vecchia, C. Mingioni, M. Nenni, R. Panero
INFN-Torino, Torino, Italy
A. Battistello, P. Bottin, D. Conventi, L. Ferrari, F. Grespan, A. Pisent
INFN/LNL, Legnaro (PD), Italy
A.G. Colombo
INFN- Sez. di Padova, Padova, Italy

The Drift Tube Linac (DTL) of the European Spallation Source (ESS) is designed to operate at 352.2MHz with a duty cycle of 4% (3 ms pulse length, 14 Hz repetition period) and will accelerate a proton beam of 62.5mA pulse peak current from 3.62 to 90 MeV. This paper presents the details of the manufacturing processes with quality control reports of the components of the DTL.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO124

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paper received ※ 12 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019

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TUPO045

Optimization of Dual Axis Asymmetric Cavity for Energy Recovery Linac

cavity, linac, HOM, SRF

435

Ya.V. Shashkov, A.M. Bulygin, M. Gusarova
MEPhI, Moscow, Russia
I.V. Konoplev
JAI, Oxford, United Kingdom
F. Marhauser
JLab, Newport News, Virginia, USA
A. Seryi
SLAC, Menlo Park, California, USA

Funding: The reported study was funded by RFBR according to the research project № 18-302-00990
Optimization of the dual axis asymmetric cavity was performed to minimize the ratio of the peak magnetic and electric fields values to the accelerating voltage, to increase the distance between operating and neighbouring modes as well as to reduce the manufacturing cost of the cavity. To reach the goals several solutions have been suggested bringing the ratios to the acceptable values and leading to simplification of the manufacturing of the structure.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO045

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO003

L-band Resonant Ring for Testing RF Windows for ILC

collider, simulation, klystron, linear-collider

679

B. Du, N. Liu
Sokendai - Hayama, Hayama, Japan
T. Matsumoto, S. Michizono, T. Miura, F. Qiu
KEK, Ibaraki, Japan
T. Matsumoto, T. Miura, F. Qiu
Sokendai, Ibaraki, Japan

A resonant ring is widely used for the breakdown test of RF components under high power. It can reach power gain of more than 10dB, which is limited by the attenua-tion of the ring. An L-band resonant ring is constructed for testing RF components of International Linear Collid-er (ILC) which is based on an RF frequency of 1.3GHz. The target of the high power test is 5 MW. We have fin-ished the test of an input power of 500 W using a solid state amplifier, and the principle of the resonant ring is verified. The resonant ring is tuned to an optimal condi-tion, which is preparation for high power operation. This paper details the principle, construction, and test of the L-band resonant ring.

Poster THPO003 [2.301 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO003

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paper received ※ 13 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019

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THPO038

Status of the Power Couplers for the CSNS DTL

DTL, cavity, vacuum, operation

767

M.X. Fan, A.H. Li, B. Li, P.H. Qu, Y. Wang, X.L. Wu
CSNS, Guangdong Province, People’s Republic of China
Q. Chen, K.Y. Gong, H.C. Liu
IHEP, Beijing, People’s Republic of China

There are four Drift Tube Linac (DTL) tanks in China Spallation Neutron Source (CSNS) Project. Each DTL tank requires a power coupler with a peak power of 2 MW and a duty cycle of 1.5% for beam operation. After approximately two years machining, all four couplers were already installed in the tunnel before year 2017. Up to now, the first phase of beam tuning has been completed, the maximum transmission power of the coupler exceeds 1.7 MW with a pulse width of 650 μs and a repetition rate of 25 Hz, meanwhile, the vacuum is maintained on the order of 10^-6 Pa during the operation and no breakdown was observed. This paper describes the architecture, the fabrication, the low power test results and the high power conditioning process of the coupler. Some problems encountered are also presented.
This work was supported by Youth Innovation Promotion Association of CAS (2015011)

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO038

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paper received ※ 30 August 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO060

First RF Measurements of the 325 MHz Ladder RFQ

rfq, linac, simulation, proton

826

M. Schuett, U. Ratzinger, M. Syha
IAP, Frankfurt am Main, Germany

Funding: BMBF 05P15RFRBA
Based on the positive results of the unmodulated 325 MHz Ladder-RFQ prototype from 2013 to 2016, we developed and designed a modulated 3.3 m Ladder-RFQ*. The unmodulated prototype Ladder-RFQ features a very constant voltage along the axis. The RFQ was high power tested at the GSI test stand. It accepted 3 times the RF power level needed in operation**. That level corresponds to a Kilpatrick factor of 3.1 with a pulse length of 200 µs. The 325 MHz RFQ is designed to accelerate protons from 95 keV to 3.0 MeV according to the design parameters of the proton linac within the FAIR project. This particular high frequency creates difficulties for a 4-ROD type RFQ, which triggered the development of a Ladder RFQ with its higher symmetry. The results of the unmodulated prototype have shown, that the Ladder-RFQ is a suitable candidate for that frequency. For the present design duty cycles are feasible up to 5%. The basic design and tendering of the RFQ has been successfully completed in 2016. Manufacturing will be completed in August 2018. We will show the the finalization of manufacturing as well as first low level RF measurements of the Ladder RFQ.
*Journal of Physics: Conf. Series 874 (2017) 012048
**Proceedings of LINAC2016, East Lansing, TUPLR053

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO060

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO064

Tuning of a Four-vane RFQ for Xi’an 200 MeV Proton Application Facility

rfq, dipole, quadrupole, cavity

838

X.D. Yu, X. Guan, Q.K. Guo, Y. Lei, P.F. Ma, X.W. Wang, Q.Z. Xing, S.X. Zheng
TUB, Beijing, People’s Republic of China
B.C. Wang, Z.M. Wang, C. Zhao
NINT, Shannxi, People’s Republic of China

This paper mainly describes the procedures and results of tuning a four-vane Radio Frequency Quadrupole (RFQ) accelerator for the Xi’an 200 MeV Proton Application Facility (XiPAF) project. The 3-meter-long RFQ will accelerate a 50 keV H⁻ beam from the ECR source to 3 MeV, and deliver it to the downstream drift tube linac (DTL) with a peak current of 5 mA, pulse length of 10-40 μs and maximum repetition rate of 0.5. The machining, assembly, and RF tuning of the RFQ cavity has been completed successfully. After tuning, the relative error of the operating quadrupole mode field is within ±2.7%, and the dipole mode com-ponent is within ±1.9% of the quadrupole mode. The RFQ now is ready for high-power RF conditioning.

Poster THPO064 [1.413 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO064

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO082

Physical Design of a Rectangular RF Deflector for Ultrashort Bunch Length Measurement

cavity, electron, simulation, FEL

872

J. Bai, Q.S. Chen, K. Fan
HUST, Wuhan, People’s Republic of China

Cylindrical deflectors which are now widely used for bunch length measurement suffer from the degeneration of polarization, while rectangular deflectors can separate polarization mode easily. This paper is focused on the study of a one-cell rectangular deflector, which is considerably different from cylindrical structure or multi-cell structure. A one-cell structure is free of π mode restriction and can achieve higher deflection efficiency per unit length. The proposed scheme is expected to achieve time resolution better than 200fs with the driving power less than 1MW. Cavity optimization and beam dynamic simulation are introduced in this paper.

Poster THPO082 [0.484 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO082

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paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO100

Development of a 1.5 GHz High-power CW Magnetron for SRF Accelerator

simulation, cavity, electron, SRF

908

L. Wenliang
College of Engineering and Applied Sciences for Nanjing University, Nanjing, People’s Republic of China
S. An, Y.J. Ke, S. Lingbin, Z. Pengjiao, L. Youchun, L. Zhao, B.Z. Zhou
PLAI, Nanjing, People’s Republic of China
J.Z. Li, L.P. Zhang, Hou, R. Rui
ADS, Jiangsu Province, People’s Republic of China

An 1.5 GHz, 13.5 kW CW high-power magnetron for a superconducting RF accelerator has been developed by Andesun Technology Group Co., Ltd. with Nanjing Sanle Electronic Information Industry Group Co., Ltd., in order to replace the klystron, that could reduce the power source cost to about one-third. The cavity, output power antenna and coupling door-nob have been optimized by using CST Studio. Testing results have shown that the resonance frequency and output power have met the requirements, and the efficiency of the magnetron is higher that 78.45%.

Poster THPO100 [0.574 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO100

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO104

Development of 150.4MHz Continuous Wave Solid-state Amplifier

power-supply, controls, insertion, radiation

917

L. Zhao
Nanjing University of Aeronautics and Astronautics, Jiangning, People’s Republic of China
S. An, Y.J. Ke, Z. Pengjiao, L. Wenliang, B.Z. Zhou
PLAI, Nanjing, People’s Republic of China

A 150.4MHz to 155.4MHz, 300W continuous wave solid-state amplifier as an accelerator power source has been developed by us. In order to increase the lifetime of MOSFET and meet the requirements of every parameters, Drain voltage and quiescent current is set at a better point with a well-designed heat dissipation structure, we make the solid state amplifier stable in performance. Taking the microwave leakage into account, the chassis structure is optimized and designed, and the microwave absorption device is adopted to make the structure compact, protect other parts not affected by the microwave leakage. After the assembly is completed, the working parameters meet the design requirements very well. The MOSFET flange temperature and output parameters meet the design requirements.

Poster THPO104 [1.405 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO104

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO108

Development of an High Gradient Side Coupled Cavity for PROBE

cavity, proton, linac, target

924

S. Pitman, R. Apsimon, G. Burt
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
N. Catalán Lasheras, A. Grudiev, W. Wuensch
CERN, Geneva, Switzerland
H.L. Owen
UMAN, Manchester, United Kingdom

The PROBE project aims to develop a high gradient proton accelerator for protons with energy around 250-350 MeV for proton radiography. Detailed studies have shown that the optimum design is a side coupled cavity at S-band. With an aperture of 8 mm a gradient of 54 MV/m can be obtained with 13 MW of RF power in a 30 cm structure. A prototype cavity has been machined by VDL and diffusion bonded by Bodycote. We present initial measurements of the prototype.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO108

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paper received ※ 17 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019

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THPO109

A New Spherical Pulse Compressor Working with Degenerated "Whispering Gallery" Mode

cavity, GUI, simulation, collider

928

Z.B. Li, W. Fang, Q. Gu, Z.T. Zhao
SINAP, Shanghai, People’s Republic of China
A. Grudiev
CERN, Geneva, Switzerland

CLIC is focusing on the Compact Linear Collider. To obtain a relatively high accelerating gradient, CLIC utilizes Pulse Compressors to increase the input power of accelerators. This work is to make an alternative design for CLIC pulse compression scheme. There are several kinds of pulse compressor: SLED, BOC, SLED-Ⅱ, spherical pulse compressor and so on. Usually, a spherical cavity, including BOC, can offer a higher Q factor compared with a cylindrical cavity. This design utilizes a spherical cavity working with degenerated Whispering Gallery mode.

Slides THPO109 [1.738 MB]

Poster THPO109 [1.913 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO109

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paper received ※ 11 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019

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THPO118

Beam Transverse Coupling and 4D Emittance Measurement Simulation Studies for PITZ

emittance, quadrupole, simulation, gun

945

Q.T. Zhao, M. Krasilnikov, H.J. Qian, F. Stephan
DESY Zeuthen, Zeuthen, Germany
Q.T. Zhao
IMP/CAS, Lanzhou, People’s Republic of China

The Photo Injector Test Facility at DESY, Zeuthen site (PITZ) was built to test and optimize high brightness electron sources for Free Electron Lasers (FELs) like FLASH and the European XFEL. Although the beam emittance has been optimized and experimentally demonstrated to meet the requirements of FLASH and XFEL, transverse beam asymmetries were observed during operation of the RF guns. Based on previous studies [1], the beam asymmetries most probably stem from beam transverse coupling by quadrupole field errors in the gun section. A pair of normal and skew gun quadrupoles was successfully used for reducing the beam asymmetries in experiment. In this paper, we discuss the beam transverse coupling between X and Y planes due to quadrupole field errors and its impact onto horizontal and vertical rms emittance. Multi-quads scan and two quads with rotated slits scan were proposed to measure the 4D beam matrix for PITZ and tested by simulation, which will give the residual beam coupling after gun quadrupoles compensation and would be helpful for minimizing the 2D rms emittance experimentally.

Poster THPO118 [1.521 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO118

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paper received ※ 08 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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