LINAC2012 - List of Keywords (focusing)

Paper	Title	Other Keywords	Page
SUPB009	Linear Accelerator based on Parallel Coupled Accelerating Structure	cavity, electron, controls, klystron	19
	A.E. Levichev, A.M. Barnyakov, V.M. Pavlov BINP SB RAS, Novosibirsk, Russia Y.D. Chernousov ICKC, Novosibirsk, Russia V. Ivannikov, I.V. Shebolaev ICKC SB RAS, Novosibirsk, Russia
	Accelerating stand based on parallel coupled accelerating structure and electron gun is developed and produced. The structure consists of five accelerating cavities. The RF power feeding of accelerating cavities is provided by common exciting cavity which is performed from rectangular waveguide loaded by reactive pins. Operating frequency is 2450 MHz. Electron gun is made on the basis of RF triode. Linear accelerator was tested with different working regimes. The obtained results are following: energy is up to 4 MeV, accelerating current is up to 300 mA with pulse duration of 2.5 ns on the half of the width; energy is up to 2.5 MeV, accelerating current is up to 100 mA with pulse duration of 5 μs; energy is up to 2.5 MeV, accelerating current is up to 120 mA with pulse duration of 5 μs and beam capture of 100%. The descriptions of the accelerator elements are given in the report. The features of the parallel coupled accelerating structure are discussed. The results of the measuring accelerator’s parameters are presented.

SUPB012	Status of CH Cavity and Solenoid Design of the 17 MeV Injector for MYRRHA	solenoid, cavity, rfq, quadrupole	29
	D. Mäder, H. Klein, H. Podlech, U. Ratzinger, C. Zhang IAP, Frankfurt am Main, Germany
	Funding: This work has been supported by the EU (FP7 MAX contract number 269565) The multifunctional subcritical reactor MYRRHA (Multi-purpose hybrid research reactor for high-tech applications) will be an accelerator driven system (ADS) located in Mol (Belgium). The first accelerating section up to 17 MeV is operated at 176 MHz and consists of a 4-rod-RFQ followed by two room temperature CH cavities with integrated triplet lenses and four superconducting CH structures with intertank solenoids. Each room temperature CH cavity provides about 1 MV effective voltage gain using less than 30 kW of RF power. The superconducting resonators have been optimized for electric peak fields below 30 MV/m and magnetic peak fields below 30 mT. For save operation of the superconducting resonators the magnetic field of the intertank solenoids has to be well shielded towards the CH cavity walls. Different coil geometries have been compared to find the ideal solenoid layout.

SUPB024	Development of Permanent Magnet Focusing System for Klystrons	klystron, permanent-magnet, cathode, simulation	62
	Y. Fuwa, Y. Iwashita, H. Tongu Kyoto ICR, Uji, Kyoto, Japan S. Fukuda, S. Michizono KEK, Ibaraki, Japan
	The Distributed RF System (DRFS) for the International Linear Collider (ILC) requires thousands of klystrons. The failure rate of the power supply for solenoid focusing coil of each klystron may be a critical issue for a regular operation of the ILC. A permanent magnet beam focusing system can increase reliability and eliminate their power consumption. Since the required magnetic field is not high in this system, inexpensive anisotropic ferrite magnets can be used instead of magnets containing rare earth materials. In order to prove its feasibility, a test model of a permanent magnet focusing beam system is constructed and a power test of the klystron for DRFS with this model is under preparation. The results of magnetic field distribution measurement and the power test will be presented.

MO2A02	Increased Understanding of Beam Losses from the SNS Linac Proton Experiment	proton, linac, optics, quadrupole	115
	J. Galambos, A.V. Aleksandrov, M.A. Plum, A.P. Shishlo ORNL, Oak Ridge, Tennessee, USA E. Laface ESS, Lund, Sweden V.A. Lebedev Fermilab, Batavia, USA
	The SNS Linac has been in operation for 6 years, with its power being gradually increased. A major operation goal is the decrease of beam loss. It has been recently suggested that intra- H–beam stripping contributes significantly to beam losses in an H⁻ linac. This was tested experimentally at SNS by accelerating a proton beam. Experimental analysis results are in good agreement with the theoretical estimates. In this paper we present the operational status and experience at the SNS linac, with emphasis on understanding beam loss in terms of intra-H–beam stripping.
	Slides MO2A02 [12.869 MB]

MO3A04	Accelerator/Decelerator of Slow Neutrons	neutron, simulation, controls, dipole	133
	M. Kitaguchi Kyoto University, Research Reactor Institute, Osaka, Japan Y. Arimoto, H.M. Shimizu KEK, Ibaraki, Japan P.W. Geltenbort ILL, Grenoble, France S. Imajo Kyoto University, Kyoto, Japan Y. Iwashita Kyoto ICR, Uji, Kyoto, Japan Y. Seki RIKEN Nishina Center, Wako, Japan T. Yoshioka Kyushu University, Fukuoka, Japan
	Funding: Supported by the Quantum Beam Fundamentals Development Program MEXT, a Grant-in-Aid for Creative Scientific Research of MEXT Program No.19GS0210 and No.23244047, Yamada Science Foundation, and KEK. An accelerator/decelerator for slow neutron beams has been demonstrated. The energy of a neutron can be increased or decreased by flipping the neutron spin (directly coupled to magnetic dipole moment) in magnetic field. This device is a combination of a gradient magnetic field and an RF magnetic field. Because the RF frequency for the spin flip is a function of the external magnetic field, only neutrons that are located in a specific magnetic field level will be spin-flipped at a given RF frequency. By changing the RF frequency, the energy change can be selected in the gradient magnetic field. The maximum field of the gradient magnet is 1 T, which corresponds to the energy change of 120 neV. The magnetic field linearly decreases to 0.2T within 25 cm. By putting this device on a beamline from a pulsed neutron source, neutron rebuncher is realized. The dense slow neutrons are important to suppress the systematic errors for the measurement of neutron electric dipole moment (nEDM). The combination of spallation neutron source and this neutron rebuncher is suitable to the measurement of nEDM. A review of current status of our plan for nEDM experiment at J-PARC will be also presented.
	Slides MO3A04 [3.750 MB]

MOPB048	Linear Accelerator Based on Parallel Coupled Accelerating Structure	cavity, electron, controls, klystron	282
	A.E. Levichev, A.M. Barnyakov, V.M. Pavlov BINP SB RAS, Novosibirsk, Russia Y.D. Chernousov ICKC, Novosibirsk, Russia V. Ivannikov, I.V. Shebolaev ICKC SB RAS, Novosibirsk, Russia
	Accelerating stand based on parallel coupled accelerating structure and electron gun is developed and produced. The structure consists of five accelerating cavities. The RF power feeding of accelerating cavities is provided by common exciting cavity which is performed from rectangular waveguide loaded by reactive pins. Operating frequency is 2450 MHz. Electron gun is made on the basis of RF triode. Linear accelerator was tested with different working regimes. The obtained results are following: energy is up to 4 MeV, accelerating current is up to 300 mA with pulse duration of 2.5 ns on the half of the width; energy is up to 2.5 MeV, accelerating current is up to 100 mA with pulse duration of 5 μs; energy is up to 2.5 MeV, accelerating current is up to 120 mA with pulse duration of 5 μs and beam capture of 100%. The descriptions of the accelerator elements are given in the report. The features of the parallel coupled accelerating structure are discussed. The results of the measuring accelerator’s parameters are presented.

MOPB049	Design of Compact C-Band Standing-Wave Accelerator for Medical Radiotherapy	electron, coupling, bunching, cavity	285
	H. Yang, M.-H. Cho, W. Namkung POSTECH, Pohang, Kyungbuk, Republic of Korea S.H. Kim ANL, Argonne, USA J.-S. Oh NFRI, Daejon, Republic of Korea
	Funding: Work supported by POSTECH Physics BK21 Program. We design a C-band standing-wave accelerator for an X-ray and electron source of medical radiotherapy. The accelerator system is operated two modes, using the X-ray and electron beams. Since two modes require different energy, the accelerator is capable of producing 6-MeV, 100-mA pulsed electron beams with peak 2-MW RF power, and 7.5-MeV, 50 mA electron beams with peak 2.5-MW RF power. The beam is focused by less than 1 mm without external magnets. The accelerating structure is a bi-periodic and on-axis-coupled structure with a built-in bunching section, which consists of 3 bunching cells, 14 normal cells and a coupling cell. It is operated with the π/2-mode standing-wave. The bunching cells are designed to enhance the RF phase focusing. Each cavity is designed by the MWS code within 3% inter-cell coupling. In this paper, we present design details of RF cavities and the beam dynamics.

TUPLB12	Development of Permanent Magnet Focusing System for Klystrons	klystron, permanent-magnet, cathode, simulation	470
	Y. Fuwa, Y. Iwashita, H. Tongu Kyoto ICR, Uji, Kyoto, Japan S. Fukuda, S. Michizono KEK, Ibaraki, Japan
	The Distributed RF System (DRFS) for the International Linear Collider (ILC) requires thousands of klystrons. The failure rate of the power supply for solenoid focusing coil of each klystron may be a critical issue for a regular operation of the ILC. A permanent magnet beam focusing system can increase reliability and eliminate their power consumption. Since the required magnetic field is not high in this system, inexpensive anisotropic ferrite magnets can be used instead of magnets containing rare earth materials. In order to prove its feasibility, a test model of a permanent magnet focusing beam system is constructed and a power test of the klystron for DRFS with this model is under preparation. The results of magnetic field distribution measurement and the power test will be presented.
	Slides TUPLB12 [1.357 MB]

TUPB069	BEAMDULAC-SCL Code for Complex Approach of Beam Dynamic Investigation in SC LINAC	ion, simulation, linac, solenoid	630
	A.V. Samoshin MEPhI, Moscow, Russia
	Periodic sequences of independently phased accelerating cavities and focusing solenoids are used in MeV and GeV energy range linacs. The beam dynamic investigation is difficult for such superconducting linear accelerator. The matrix calculation was preferably used for primary choused of accelerating structure parameters. This method does not allows properly investigate the longitudinal motion. The smooth approximation can be used to investigate the nonlinear ion beam dynamics in such accelerating structure and to calculate longitudinal and transverse acceptances. The potential function and the equation of motion in the Hamilton form are devised by the smooth approximation. The advantages and disadvantages of each method will describe, the results of investigation will compare. The user friendly software BEAMDULAC-SCL for ion beam dynamic analysis was created. A numerical simulation of beam dynamics in the real field are carried out for the different variants of the accelerator structure based on previously analytically obtained results.

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

TUPB090	Development of Permanent Magnet Focusing System for Klystrons	klystron, permanent-magnet, cathode, simulation	669
	Y. Fuwa, Y. Iwashita, H. Tongu Kyoto ICR, Uji, Kyoto, Japan S. Fukuda, S. Michizono KEK, Ibaraki, Japan
	A permanent magnet focusing system for klystrons is under development to improve reliability of RF supply system and reduce power consumption. To save production cost, anisotropic ferrite magnets are used in this system. A test model has been fabricated and the power test of a 750 kW klystron with this focusing magnet is carried out. 60 % of the nominal output power has been achieved at a preliminary power test so far

THPLB04	Preliminary Study of Proton Beam Transport in a 10 MeV Dielectric Wall Accelerator	proton, accelerating-gradient, injection, ion	816
	J. Zhu, S. Chen, J. Deng, Y. Shen, J. Shi, W.D. Wang, L.S. Xia, H. Zhang, L.W. Zhang CAEP/IFP, Mainyang, Sichuan, People's Republic of China
	Funding: Nuclear Energy Technology Development project; National Natural Science Foundation of China (11035004) A novel proton accelerator based on Dielectric Wall Accelerator (DWA) technology is being developed at Institute of Fluid Physics (IFP). The accelerating gradient will be 20 MV/m or even higher based on current high gradient insulator (HIG) performance. Theoretical study and numerical simulation of accelerating the proton beam to 10 MeV by virtual traveling wave method is presented in this paper. The beam dynamics under accelerating pulse with or without flattop is discussed.
	Slides THPLB04 [1.191 MB]

THPLB11	Experimental and Simulation Study of the Long-path-length Dynamics of a Space-charge-dominated Bunch	simulation, space-charge, electron, emittance	834
	I. Haber, B.L. Beaudoin, S. Bernal, R.A. Kishek, T.W. Koeth, Y. Mo UMD, College Park, Maryland, USA
	Funding: Work supported by the United States Department of Energy and the Office of Naval Research. The University of Maryland Electron Ring (UMER) is a low-energy (10 keV) electron facility built to study, on a scaled machine, the long-propagation-length evolution of a space-charge-dominated beam. Though constructed in a ring geometry to achieve a long path length at modest cost, UMER has observed important space-charge physics directly relevant to linear machines. Examples will be presented that emphasize studies of the longitudinal dynamics and comparisons to axisymmetric simulations. The detailed agreement obtained between simulation and experiment will be presented as evidence that the longitudinal physics observed is not strongly influenced by the ring geometry. Novel phenomena such as soliton formation, unimpeded bunch-end interpenetration, and an instability that occurs after this interpenetration, will be discussed.

THPB002	Preliminary Study of Proton Beam Transport in a 10 MeV Dielectric Wall Accelerator	proton, accelerating-gradient, injection, ion	840
	J. Zhu, S. Chen, J. Deng, Y. Shen, J. Shi, W.D. Wang, L.S. Xia, H. Zhang, L.W. Zhang CAEP/IFP, Mainyang, Sichuan, People's Republic of China Y. Liu Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, Sichuan, People's Republic of China
	Funding: Nuclear Energy Technology Development project; National Natural Science Foundation of China (11035004) A novel proton accelerator based on Dielectric Wall Accelerator (DWA) technology is being developed at Institute of Fluid Physics (IFP). The accelerating gradient will be 20 MV/m or even higher based on current high gradient insulator (HIG) performance. Theoretical study and numerical simulation of accelerating the proton beam to 10 MeV by virtual traveling wave method is presented in this paper. The beam dynamics under accelerating pulse with or without flattop is discussed.

THPB009	Status of CH Cavity and Solenoid Design of the 17 MeV Injector for MYRRHA	solenoid, cavity, rfq, quadrupole	861
	D. Mäder, H. Klein, H. Podlech, U. Ratzinger, C. Zhang IAP, Frankfurt am Main, Germany
	Funding: This work has been supported by the EU (FP7 MAX contract number 269565) The multifunctional subcritical reactor MYRRHA (Multi-purpose hybrid research reactor for high-tech applications) will be an accelerator driven system (ADS) located in Mol (Belgium). The first accelerating section up to 17 MeV is operated at 176 MHz and consists of a 4-rod-RFQ followed by two room temperature CH cavities with integrated triplet lenses and four superconducting CH structures with intertank solenoids. Each room temperature CH cavity provides about 1 MV effective voltage gain using less than 30 kW of RF power. The superconducting resonators have been optimized for electric peak fields below 30 MV/m and magnetic peak fields below 30 mT. For save operation of the superconducting resonators the magnetic field of the intertank solenoids has to be well shielded towards the CH cavity walls. Different coil geometries have been compared to find the ideal solenoid layout.

THPB061	Experimental and Simulation Study of the Long-path-length Dynamics of a Space-charge-dominated Bunch	simulation, space-charge, electron, emittance	978
	I. Haber, B.L. Beaudoin, S. Bernal, R.A. Kishek, T.W. Koeth, Y. Mo UMD, College Park, Maryland, USA
	Funding: Work supported by the United States Department of Energy and the Office of Naval Research. The University of Maryland Electron Ring (UMER) is a low-energy (10 keV) electron facility built to study, on a scaled machine, the long-propagation-length evolution of a space-charge-dominated beam. Though constructed in a ring geometry to achieve a long path length at modest cost, UMER has observed important space-charge physics directly relevant to linear machines. Examples will be presented that emphasize studies of the longitudinal dynamics and comparisons to axisymmetric simulations. The detailed agreement obtained between simulation and experiment will be presented as evidence that the longitudinal physics observed is not strongly influenced by the ring geometry. Novel phenomena such as soliton formation, unimpeded bunch-end interpenetration, and an instability that occurs after this interpenetration, will be discussed.

THPB068	First Observation of Photoemission Enhancement from Copper Cathode Illuminated by Z-Polarized Laser Pulse	laser, cathode, polarization, gun	996
	H. Tomizawa, H. Dewa, A. Mizuno, T. Taniuchi JASRI/SPring-8, Hyogo, Japan
	Since 2006, we have developed a novel photocathode gun gated by laser-induced Schottky-effect. This new type of gun utilizes a laser’s coherency to aim at a compact femtosecond laser oscillator as an IR laser source using Z-polarization on the photocathode. This Z-polarization scheme reduces the laser photon energy (making it possible to excite the cathode with a longer wavelength) by reducing the work function of cathode due to Schottky effect. A hollow laser incidence is applied with a hollow convex lens in a vacuum that is focused after passing the laser beam through a radial polarizer. According to our calculations (convex lens: NA=0.15), a Z-field of 1 GV/m needs 1.26 MW at peak power for the fundamental wavelength (792 nm). In the first demonstration of Z-field emission, enhancement was done with a copper cathode at THG (264 nm). Consequently, we observed 1.4 times enhancement of photoemission at 1.6 GV/m of an averaged laser Z-field on the cathode surface. We report the first observation and analysis of the emission enhancements with this laser-induced Schottky-effect on metal copper photocathodes by comparing radial and azimuthal polarizations of the incident laser pulses.

THPB079	Development of a Superconducting Focusing Solenoid for CADS	solenoid, cavity, linac, dipole	1011
	W. Wu, S.F. Han, Y. He, L.Z. Ma, D.S. Ni, Z.J. Wang, B.M. Wu, W.J. Yang, X.L. Yang, S.J. Zheng, L. Zhu IMP, Lanzhou, People's Republic of China
	A superconducting focusing solenoid has been designed and developed for the China Accelerator Driven System (CADS). In order to meet the requirement of focusing strength and fringe field while minimizing physical size of the solenoid, the novel optimizing design method based on linear programming method was employed. In this report, we will introduce the design of the solenoid including magnetic field optimization, mechanical design and quench protection. The fabrication and the test results of the solenoid will also be introduced in this report.

Paper

Title

Other Keywords

Page

SUPB009

Linear Accelerator based on Parallel Coupled Accelerating Structure

cavity, electron, controls, klystron

19

A.E. Levichev, A.M. Barnyakov, V.M. Pavlov
BINP SB RAS, Novosibirsk, Russia
Y.D. Chernousov
ICKC, Novosibirsk, Russia
V. Ivannikov, I.V. Shebolaev
ICKC SB RAS, Novosibirsk, Russia

Accelerating stand based on parallel coupled accelerating structure and electron gun is developed and produced. The structure consists of five accelerating cavities. The RF power feeding of accelerating cavities is provided by common exciting cavity which is performed from rectangular waveguide loaded by reactive pins. Operating frequency is 2450 MHz. Electron gun is made on the basis of RF triode. Linear accelerator was tested with different working regimes. The obtained results are following: energy is up to 4 MeV, accelerating current is up to 300 mA with pulse duration of 2.5 ns on the half of the width; energy is up to 2.5 MeV, accelerating current is up to 100 mA with pulse duration of 5 μs; energy is up to 2.5 MeV, accelerating current is up to 120 mA with pulse duration of 5 μs and beam capture of 100%. The descriptions of the accelerator elements are given in the report. The features of the parallel coupled accelerating structure are discussed. The results of the measuring accelerator’s parameters are presented.

SUPB012

Status of CH Cavity and Solenoid Design of the 17 MeV Injector for MYRRHA

solenoid, cavity, rfq, quadrupole

29

D. Mäder, H. Klein, H. Podlech, U. Ratzinger, C. Zhang
IAP, Frankfurt am Main, Germany

Funding: This work has been supported by the EU (FP7 MAX contract number 269565)
The multifunctional subcritical reactor MYRRHA (Multi-purpose hybrid research reactor for high-tech applications) will be an accelerator driven system (ADS) located in Mol (Belgium). The first accelerating section up to 17 MeV is operated at 176 MHz and consists of a 4-rod-RFQ followed by two room temperature CH cavities with integrated triplet lenses and four superconducting CH structures with intertank solenoids. Each room temperature CH cavity provides about 1 MV effective voltage gain using less than 30 kW of RF power. The superconducting resonators have been optimized for electric peak fields below 30 MV/m and magnetic peak fields below 30 mT. For save operation of the superconducting resonators the magnetic field of the intertank solenoids has to be well shielded towards the CH cavity walls. Different coil geometries have been compared to find the ideal solenoid layout.

SUPB024

Development of Permanent Magnet Focusing System for Klystrons

klystron, permanent-magnet, cathode, simulation

62

Y. Fuwa, Y. Iwashita, H. Tongu
Kyoto ICR, Uji, Kyoto, Japan
S. Fukuda, S. Michizono
KEK, Ibaraki, Japan

The Distributed RF System (DRFS) for the International Linear Collider (ILC) requires thousands of klystrons. The failure rate of the power supply for solenoid focusing coil of each klystron may be a critical issue for a regular operation of the ILC. A permanent magnet beam focusing system can increase reliability and eliminate their power consumption. Since the required magnetic field is not high in this system, inexpensive anisotropic ferrite magnets can be used instead of magnets containing rare earth materials. In order to prove its feasibility, a test model of a permanent magnet focusing beam system is constructed and a power test of the klystron for DRFS with this model is under preparation. The results of magnetic field distribution measurement and the power test will be presented.

MO2A02

Increased Understanding of Beam Losses from the SNS Linac Proton Experiment

proton, linac, optics, quadrupole

115

J. Galambos, A.V. Aleksandrov, M.A. Plum, A.P. Shishlo
ORNL, Oak Ridge, Tennessee, USA
E. Laface
ESS, Lund, Sweden
V.A. Lebedev
Fermilab, Batavia, USA

The SNS Linac has been in operation for 6 years, with its power being gradually increased. A major operation goal is the decrease of beam loss. It has been recently suggested that intra- H–beam stripping contributes significantly to beam losses in an H⁻ linac. This was tested experimentally at SNS by accelerating a proton beam. Experimental analysis results are in good agreement with the theoretical estimates. In this paper we present the operational status and experience at the SNS linac, with emphasis on understanding beam loss in terms of intra-H–beam stripping.

Slides MO2A02 [12.869 MB]

MO3A04

Accelerator/Decelerator of Slow Neutrons

neutron, simulation, controls, dipole

133

M. Kitaguchi
Kyoto University, Research Reactor Institute, Osaka, Japan
Y. Arimoto, H.M. Shimizu
KEK, Ibaraki, Japan
P.W. Geltenbort
ILL, Grenoble, France
S. Imajo
Kyoto University, Kyoto, Japan
Y. Iwashita
Kyoto ICR, Uji, Kyoto, Japan
Y. Seki
RIKEN Nishina Center, Wako, Japan
T. Yoshioka
Kyushu University, Fukuoka, Japan

Funding: Supported by the Quantum Beam Fundamentals Development Program MEXT, a Grant-in-Aid for Creative Scientific Research of MEXT Program No.19GS0210 and No.23244047, Yamada Science Foundation, and KEK.
An accelerator/decelerator for slow neutron beams has been demonstrated. The energy of a neutron can be increased or decreased by flipping the neutron spin (directly coupled to magnetic dipole moment) in magnetic field. This device is a combination of a gradient magnetic field and an RF magnetic field. Because the RF frequency for the spin flip is a function of the external magnetic field, only neutrons that are located in a specific magnetic field level will be spin-flipped at a given RF frequency. By changing the RF frequency, the energy change can be selected in the gradient magnetic field. The maximum field of the gradient magnet is 1 T, which corresponds to the energy change of 120 neV. The magnetic field linearly decreases to 0.2T within 25 cm. By putting this device on a beamline from a pulsed neutron source, neutron rebuncher is realized. The dense slow neutrons are important to suppress the systematic errors for the measurement of neutron electric dipole moment (nEDM). The combination of spallation neutron source and this neutron rebuncher is suitable to the measurement of nEDM. A review of current status of our plan for nEDM experiment at J-PARC will be also presented.

Slides MO3A04 [3.750 MB]

MOPB048

Linear Accelerator Based on Parallel Coupled Accelerating Structure

cavity, electron, controls, klystron

282

A.E. Levichev, A.M. Barnyakov, V.M. Pavlov
BINP SB RAS, Novosibirsk, Russia
Y.D. Chernousov
ICKC, Novosibirsk, Russia
V. Ivannikov, I.V. Shebolaev
ICKC SB RAS, Novosibirsk, Russia

Accelerating stand based on parallel coupled accelerating structure and electron gun is developed and produced. The structure consists of five accelerating cavities. The RF power feeding of accelerating cavities is provided by common exciting cavity which is performed from rectangular waveguide loaded by reactive pins. Operating frequency is 2450 MHz. Electron gun is made on the basis of RF triode. Linear accelerator was tested with different working regimes. The obtained results are following: energy is up to 4 MeV, accelerating current is up to 300 mA with pulse duration of 2.5 ns on the half of the width; energy is up to 2.5 MeV, accelerating current is up to 100 mA with pulse duration of 5 μs; energy is up to 2.5 MeV, accelerating current is up to 120 mA with pulse duration of 5 μs and beam capture of 100%. The descriptions of the accelerator elements are given in the report. The features of the parallel coupled accelerating structure are discussed. The results of the measuring accelerator’s parameters are presented.

MOPB049

Design of Compact C-Band Standing-Wave Accelerator for Medical Radiotherapy

electron, coupling, bunching, cavity

285

H. Yang, M.-H. Cho, W. Namkung
POSTECH, Pohang, Kyungbuk, Republic of Korea
S.H. Kim
ANL, Argonne, USA
J.-S. Oh
NFRI, Daejon, Republic of Korea

Funding: Work supported by POSTECH Physics BK21 Program.
We design a C-band standing-wave accelerator for an X-ray and electron source of medical radiotherapy. The accelerator system is operated two modes, using the X-ray and electron beams. Since two modes require different energy, the accelerator is capable of producing 6-MeV, 100-mA pulsed electron beams with peak 2-MW RF power, and 7.5-MeV, 50 mA electron beams with peak 2.5-MW RF power. The beam is focused by less than 1 mm without external magnets. The accelerating structure is a bi-periodic and on-axis-coupled structure with a built-in bunching section, which consists of 3 bunching cells, 14 normal cells and a coupling cell. It is operated with the π/2-mode standing-wave. The bunching cells are designed to enhance the RF phase focusing. Each cavity is designed by the MWS code within 3% inter-cell coupling. In this paper, we present design details of RF cavities and the beam dynamics.

TUPLB12

Development of Permanent Magnet Focusing System for Klystrons

klystron, permanent-magnet, cathode, simulation

470

Y. Fuwa, Y. Iwashita, H. Tongu
Kyoto ICR, Uji, Kyoto, Japan
S. Fukuda, S. Michizono
KEK, Ibaraki, Japan

The Distributed RF System (DRFS) for the International Linear Collider (ILC) requires thousands of klystrons. The failure rate of the power supply for solenoid focusing coil of each klystron may be a critical issue for a regular operation of the ILC. A permanent magnet beam focusing system can increase reliability and eliminate their power consumption. Since the required magnetic field is not high in this system, inexpensive anisotropic ferrite magnets can be used instead of magnets containing rare earth materials. In order to prove its feasibility, a test model of a permanent magnet focusing beam system is constructed and a power test of the klystron for DRFS with this model is under preparation. The results of magnetic field distribution measurement and the power test will be presented.

Slides TUPLB12 [1.357 MB]

TUPB069

BEAMDULAC-SCL Code for Complex Approach of Beam Dynamic Investigation in SC LINAC

ion, simulation, linac, solenoid

630

A.V. Samoshin
MEPhI, Moscow, Russia

Periodic sequences of independently phased accelerating cavities and focusing solenoids are used in MeV and GeV energy range linacs. The beam dynamic investigation is difficult for such superconducting linear accelerator. The matrix calculation was preferably used for primary choused of accelerating structure parameters. This method does not allows properly investigate the longitudinal motion. The smooth approximation can be used to investigate the nonlinear ion beam dynamics in such accelerating structure and to calculate longitudinal and transverse acceptances. The potential function and the equation of motion in the Hamilton form are devised by the smooth approximation. The advantages and disadvantages of each method will describe, the results of investigation will compare. The user friendly software BEAMDULAC-SCL for ion beam dynamic analysis was created. A numerical simulation of beam dynamics in the real field are carried out for the different variants of the accelerator structure based on previously analytically obtained results.

TUPB070

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

linac, solenoid, proton, acceleration

633

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

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

TUPB090

Development of Permanent Magnet Focusing System for Klystrons

klystron, permanent-magnet, cathode, simulation

669

Y. Fuwa, Y. Iwashita, H. Tongu
Kyoto ICR, Uji, Kyoto, Japan
S. Fukuda, S. Michizono
KEK, Ibaraki, Japan

A permanent magnet focusing system for klystrons is under development to improve reliability of RF supply system and reduce power consumption. To save production cost, anisotropic ferrite magnets are used in this system. A test model has been fabricated and the power test of a 750 kW klystron with this focusing magnet is carried out. 60 % of the nominal output power has been achieved at a preliminary power test so far

THPLB04

Preliminary Study of Proton Beam Transport in a 10 MeV Dielectric Wall Accelerator

proton, accelerating-gradient, injection, ion

816

J. Zhu, S. Chen, J. Deng, Y. Shen, J. Shi, W.D. Wang, L.S. Xia, H. Zhang, L.W. Zhang
CAEP/IFP, Mainyang, Sichuan, People's Republic of China

Funding: Nuclear Energy Technology Development project; National Natural Science Foundation of China (11035004)
A novel proton accelerator based on Dielectric Wall Accelerator (DWA) technology is being developed at Institute of Fluid Physics (IFP). The accelerating gradient will be 20 MV/m or even higher based on current high gradient insulator (HIG) performance. Theoretical study and numerical simulation of accelerating the proton beam to 10 MeV by virtual traveling wave method is presented in this paper. The beam dynamics under accelerating pulse with or without flattop is discussed.

Slides THPLB04 [1.191 MB]

THPLB11

Experimental and Simulation Study of the Long-path-length Dynamics of a Space-charge-dominated Bunch

simulation, space-charge, electron, emittance

834

I. Haber, B.L. Beaudoin, S. Bernal, R.A. Kishek, T.W. Koeth, Y. Mo
UMD, College Park, Maryland, USA

Funding: Work supported by the United States Department of Energy and the Office of Naval Research.
The University of Maryland Electron Ring (UMER) is a low-energy (10 keV) electron facility built to study, on a scaled machine, the long-propagation-length evolution of a space-charge-dominated beam. Though constructed in a ring geometry to achieve a long path length at modest cost, UMER has observed important space-charge physics directly relevant to linear machines. Examples will be presented that emphasize studies of the longitudinal dynamics and comparisons to axisymmetric simulations. The detailed agreement obtained between simulation and experiment will be presented as evidence that the longitudinal physics observed is not strongly influenced by the ring geometry. Novel phenomena such as soliton formation, unimpeded bunch-end interpenetration, and an instability that occurs after this interpenetration, will be discussed.

THPB002

Preliminary Study of Proton Beam Transport in a 10 MeV Dielectric Wall Accelerator

proton, accelerating-gradient, injection, ion

840

J. Zhu, S. Chen, J. Deng, Y. Shen, J. Shi, W.D. Wang, L.S. Xia, H. Zhang, L.W. Zhang
CAEP/IFP, Mainyang, Sichuan, People's Republic of China
Y. Liu
Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, Sichuan, People's Republic of China

Funding: Nuclear Energy Technology Development project; National Natural Science Foundation of China (11035004)
A novel proton accelerator based on Dielectric Wall Accelerator (DWA) technology is being developed at Institute of Fluid Physics (IFP). The accelerating gradient will be 20 MV/m or even higher based on current high gradient insulator (HIG) performance. Theoretical study and numerical simulation of accelerating the proton beam to 10 MeV by virtual traveling wave method is presented in this paper. The beam dynamics under accelerating pulse with or without flattop is discussed.

THPB009

Status of CH Cavity and Solenoid Design of the 17 MeV Injector for MYRRHA

solenoid, cavity, rfq, quadrupole

861

D. Mäder, H. Klein, H. Podlech, U. Ratzinger, C. Zhang
IAP, Frankfurt am Main, Germany

Funding: This work has been supported by the EU (FP7 MAX contract number 269565)
The multifunctional subcritical reactor MYRRHA (Multi-purpose hybrid research reactor for high-tech applications) will be an accelerator driven system (ADS) located in Mol (Belgium). The first accelerating section up to 17 MeV is operated at 176 MHz and consists of a 4-rod-RFQ followed by two room temperature CH cavities with integrated triplet lenses and four superconducting CH structures with intertank solenoids. Each room temperature CH cavity provides about 1 MV effective voltage gain using less than 30 kW of RF power. The superconducting resonators have been optimized for electric peak fields below 30 MV/m and magnetic peak fields below 30 mT. For save operation of the superconducting resonators the magnetic field of the intertank solenoids has to be well shielded towards the CH cavity walls. Different coil geometries have been compared to find the ideal solenoid layout.

THPB061

Experimental and Simulation Study of the Long-path-length Dynamics of a Space-charge-dominated Bunch

simulation, space-charge, electron, emittance

978

I. Haber, B.L. Beaudoin, S. Bernal, R.A. Kishek, T.W. Koeth, Y. Mo
UMD, College Park, Maryland, USA

Funding: Work supported by the United States Department of Energy and the Office of Naval Research.
The University of Maryland Electron Ring (UMER) is a low-energy (10 keV) electron facility built to study, on a scaled machine, the long-propagation-length evolution of a space-charge-dominated beam. Though constructed in a ring geometry to achieve a long path length at modest cost, UMER has observed important space-charge physics directly relevant to linear machines. Examples will be presented that emphasize studies of the longitudinal dynamics and comparisons to axisymmetric simulations. The detailed agreement obtained between simulation and experiment will be presented as evidence that the longitudinal physics observed is not strongly influenced by the ring geometry. Novel phenomena such as soliton formation, unimpeded bunch-end interpenetration, and an instability that occurs after this interpenetration, will be discussed.

THPB068

First Observation of Photoemission Enhancement from Copper Cathode Illuminated by Z-Polarized Laser Pulse

laser, cathode, polarization, gun

996

H. Tomizawa, H. Dewa, A. Mizuno, T. Taniuchi
JASRI/SPring-8, Hyogo, Japan

Since 2006, we have developed a novel photocathode gun gated by laser-induced Schottky-effect. This new type of gun utilizes a laser’s coherency to aim at a compact femtosecond laser oscillator as an IR laser source using Z-polarization on the photocathode. This Z-polarization scheme reduces the laser photon energy (making it possible to excite the cathode with a longer wavelength) by reducing the work function of cathode due to Schottky effect. A hollow laser incidence is applied with a hollow convex lens in a vacuum that is focused after passing the laser beam through a radial polarizer. According to our calculations (convex lens: NA=0.15), a Z-field of 1 GV/m needs 1.26 MW at peak power for the fundamental wavelength (792 nm). In the first demonstration of Z-field emission, enhancement was done with a copper cathode at THG (264 nm). Consequently, we observed 1.4 times enhancement of photoemission at 1.6 GV/m of an averaged laser Z-field on the cathode surface. We report the first observation and analysis of the emission enhancements with this laser-induced Schottky-effect on metal copper photocathodes by comparing radial and azimuthal polarizations of the incident laser pulses.

THPB079

Development of a Superconducting Focusing Solenoid for CADS

solenoid, cavity, linac, dipole

1011

W. Wu, S.F. Han, Y. He, L.Z. Ma, D.S. Ni, Z.J. Wang, B.M. Wu, W.J. Yang, X.L. Yang, S.J. Zheng, L. Zhu
IMP, Lanzhou, People's Republic of China

A superconducting focusing solenoid has been designed and developed for the China Accelerator Driven System (CADS). In order to meet the requirement of focusing strength and fringe field while minimizing physical size of the solenoid, the novel optimizing design method based on linear programming method was employed. In this report, we will introduce the design of the solenoid including magnetic field optimization, mechanical design and quench protection. The fabrication and the test results of the solenoid will also be introduced in this report.