HB2012 - List of Keywords (acceleration)

Paper	Title	Other Keywords	Page
MOI1B02	Technological Challenges for High-Intensity Proton Rings	linac, proton, injection, space-charge	15
	Y. Yamazaki FRIB, East Lansing, Michigan, USA
	Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 High-intensity, pulsed proton accelerators have been and will be requested by a wide variety of scientific fields and industrial and medical applications, for example, pulsed spallation neutron sources and neutrino sources. We will focus our discussion on the proton rings with a pulse length of a few μsec and a beam power of MW. These accelerators may be used for boosting injectors to higher-energy accelerators, like a neutrino factories. At first, we will discuss on the space-charge force which limit the stored charges in a ring together with the negative-ion injection scheme. The pulsed spallation neutron sources are classified into two schemes. One is the combination of a full-energy linac and an accumulation ring (AR) exemplified by SNS and LANSCE. The other is that of a low-energy linac and a Rapid-Cycle Synchrotron (RCS) exemplified by J-PARC RCS and ISIS. In general, pros and cons of accelerator schemes are dependent upon the technological development results. Pros and cons of AR versus RCS will be discussed on the basis of recent technological developments and beam experiment data together with the future perspectives for MW-class machines.
	Slides MOI1B02 [3.850 MB]

MOI1B03	Technical Challenges in Multi-MW Proton Linacs	linac, rfq, cryomodule, proton	20
	V.A. Lebedev Fermilab, Batavia, USA
	The intensity frontier research is an important part of modern elementary particle physics. It uses proton beams to create secondary beams consisting of, but not necessary limited to, neutrinos, muons, kaons and neutrons. Deferent experiments require different time structure of proton beams but all of them require the beam power of about or exceeding 1 MW. In addition, powerful proton linacs can find an application in accelerator driven nuclear reactors and transmutation of radioactive waste. Recent advances in the superconducting RF technology make a multi-MW power level economically acceptable. This paper discusses main physics and technical limitations determining ultimate parameters of such accelerators, their structure and performance.
	Slides MOI1B03 [2.863 MB]

MOP209	High Intensity Proton FFAG Ring with Serpentine Acceleration for ADS	proton, closed-orbit, transverse-dynamics, injection	60
	E. Yamakawa, Y. Ishi, Y. Kuriyama, J.-B. Lagrange, Y. Mori, T. Uesugi Kyoto University, Research Reactor Institute, Osaka, Japan
	In order to produce high intensity proton beam for ADS, a new type of fixed rf acceleration scheme, so-called serpentine acceleration, is examined in scaling FFAG. Longitudinal hamiltonian for scaling FFAG is first derived analytically. Then the features of serpentine acceleration in longitudinal phase space are studied. Ring design for ADS is finally shown.

MOP210	Beam Stacking for High Intensity Pulsed Proton Beam with FFAG	simulation, extraction, neutron, injection	64
	Y. Mori, Y. Ishi, Y. Kuriyama, J.-B. Lagrange, T. Uesugi Kyoto University, Research Reactor Institute, Osaka, Japan
	Multi-beam stacking scheme to generate an intense short-pulsed proton beam with high repetition proton FFAG is presented.

MOP216	The Design Study on the Longitudinal Beam Dynamics for CSNS/RCS	injection, simulation, space-charge, bunching	89
	N. Wang, M.Y. Huang, Y. Li, S. Wang, S.Y. Xu, Y.S. Yuan IHEP, Beijing, People's Republic of China
	Rapid Cycling Synchrotron (RCS) is the key part of China Spallation Neutron Source (CSNS) accelerators. The RCS accumulates and accelerates 80 MeV beam from linac to 1.6 GeV. The particle number is 1.56·10¹³ for each pulse, with repetition rate of 25 Hz. In the RCS, longitudinal beam dynamics plays a crucial role in achieving high intensity beam with low beam loss. Longitudinal parameters are studied and optimized for efficient RF trapping of the beam in the longitudinal phase space. Beam performance is investigated by particle tracking simulations. Beam dynamic issues related to the high order mode induced by the RF generator are studied with a new developed code. Primary study on the adoption of dual harmonic cavity for higher beam power is also addressed.

MOP255	Acceleration in Vertical Orbit Excursion FFAGs with Edge Focussing	space-charge, proton, simulation, injection	197
	S.J. Brooks STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
	FFAGs with vertical orbit excursion (VFFAGs) provide a promising alternative design for rings with fixed-field superconducting magnets. They have a vertical magnetic field component that increases with height in the vertical aperture, yielding a skew quadrupole focussing structure. Edge focussing can provide an alternating gradient within each magnet, thus reducing the ring circumference. Like spiral scaling horizontal FFAGs (but not non-scaling ones) the machine has fixed tunes and no intrinsic limitation on momentum range. Rings to accelerate the 800MeV beam from the ISIS proton synchrotron are investigated, in terms of both magnet field geometry and longitudinal behaviour during acceleration with space charge. The 12GeV ring produces an output power of at least 2.18MW.

TUO1C05	Measurements and Interpretation of the Betatron Tune Spectra of High Intensity Bunched Beam at SIS-18	space-charge, synchrotron, ion, injection	310
	R. Singh, O. Chorniy, P. Forck, R. Haseitl, W. Kaufmann, P. Kowina, K. Lang GSI, Darmstadt, Germany O. Boine-Frankenheim, R. Singh, T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany
	The paper presents the status of the transverse tune measurements in the synchrotron SIS18 at GSI. Presently, there are two systems for tune measurements in operation in the SIS18, namely TOPOS (Tune, Orbit and POsition measurement System) and BBQ (Base Band tune measurement system). The first one is a digital system where the BPM signal is digitized and the bunch position is calculated numerically. The second system is an analog system, where the transverse bunch motion is detected using peak detector. Band limited noise and chirp excitations were used to excite the betatron oscillations. Measurements of the betatron tune spectra were done at injection energy at medium and high intensities. In the frequency spectra a number of peaks around the position of betatron tune were seen. The peaks can be attributed to different bunch head-tail modes which were observed in time domain. These modes were dependent on the beam intensity. In this paper we compare the tune spectra measured at high beam intensity with the theoretical model for the space charge affected head-tail modes.
	Slides TUO1C05 [1.315 MB]

THO1A03	Dual-harmonic Acceleration Studies at CSNS RCS	injection, simulation, bunching, cavity	487
	J.F. Chen, J.Y. Tang, X. Zhang IHEP, Beijing, People's Republic of China
	Dual harmonic acceleration is proposed to alleviate the space charge effects in the RCS (Rapid Cycling Synchrotron) at the upgrading stages of the CSNS (China Spallation Neutron Source). Different dual harmonic acceleration schemes have been studied by using a self-made parameter calculation code - RAMADH and the simulation code - ORBIT. Both complete and partial coverage of the dual harmonic RF system along the acceleration have been considered. The injection by combining beam chopping and off-momentum is used in the macro-particle tracking simulations by ORBIT. In addition, a new idea that unlocks the RF frequency and the magnetic field in the injection period is found very useful in obtaining a good longitudinal painting.
	Slides THO1A03 [1.343 MB]

THO1C02	Beam Loss Control in the ISIS Accelerator Facility	injection, synchrotron, controls, proton	560
	D.J. Adams, B. Jones, A.H. Kershaw, S.J. Payne, B.G. Pine, H. V. Smith, C.M. Warsop, R.E. Williamson, M. Wright STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	The ISIS spallation neutron and muon source has been in operation since 1984. The accelerator complex consists of an H⁻ ion source, RFQ, 70 MeV linac, 800 MeV proton synchrotron and associated beam lines. The facility currently delivers ~2.8·10¹³ protons per pulse at 50 Hz, splitting the pulses 40/10 between two neutron target stations. High intensity performance and operation are dominated by the need to control beam loss, which is key to sustainable machine operation and hands on maintenance. Beam loss measurement systems on ISIS are described, along with typical operational levels. The dominant beam loss in the facility occurs in the synchrotron due to high intensity effects during the H⁻ injection and longitudinal trapping processes. These losses are localised in a single superperiod using a beam collector system. Emittance growth during acceleration also drives extraction and beam transport loss at 800 MeV. Measurements, simulation and correction systems for these processes are discussed, as are the implications for further intensity upgrades.
	Slides THO1C02 [4.759 MB]

THO1C06	Recent Commissioning of High-intensity Proton Beams in J-PARC Main Ring	beam-losses, injection, proton, kicker	575
	Y. Sato, K. Hara, Y. Hashimoto, Y. Hori, S. Igarashi, K. Ishii, N. Kamikubota, T. Koseki, Y. Kurimoto, K. Niki, K. Ohmi, C. Ohmori, M. Okada, M. Shimamoto, M.J. Shirakata, T. Sugimoto, J. Takano, M. Tejima, T. Toyama, M. Uota, S. Yamada, N. Yamamoto, M. Yoshii KEK, Ibaraki, Japan S. Hatakeyama, H. Hotchi, F. Tamura JAEA/J-PARC, Tokai-mura, Japan S. Nakamura, K. Satou J-PARC, KEK & JAEA, Ibaraki-ken, Japan
	J-PARC main ring (MR) provides high power proton beams of 200 kW to the neutrino experiment. Beam losses were well managed within capacity of collimation system. Since this beam power was achieved by shortening the repetition rate, following tunings had been applied in order to reduce the beam losses, such as improvement of tune flatness, chromaticity correction, upgrades of injection kickers, dynamic bunch-by-bunch feed-back to suppress transverse oscillation, beam loading compensation using feed-forward technique, and balancing the collimators of MR and the injection beam transport line. The dynamic bunch-by-bunch feed-back was effective to reduce the beam losses to one-tenth during injection and beginning of acceleration. With the beam loading compensation, impedance seen by the beam was significantly reduced, longitudinal oscillations were damped, and the beam power was increased over 5% without increasing the beam losses. Monitors were upgraded to find time structure and location of the beam losses, even in first several turns after each injection. In this presentation these commissioning procedures and beam dynamics simulations are shown, and our upgrade plan is discussed.
	Slides THO1C06 [2.193 MB]

THO3C04	Longitudinal Beam Diagnosis with RF Chopper System	cavity, linac, neutron, DTL	591
	T. Maruta JAEA/J-PARC, Tokai-mura, Japan M. Ikegami KEK, Ibaraki, Japan
	J-PARC linac has a chopper system between RFQ and DTL, which utilizes an RF deflector cavity instead of a usual slow wave kicker. Taking advantage of this unique feature of the chopper system, we have experimentally measured the longitudinal full width of phase direction at the chopper cavity. In this presentation, I would like to discuss the measurement technique and measurement results.
	Slides THO3C04 [2.495 MB]

Paper

Title

Other Keywords

Page

MOI1B02

Technological Challenges for High-Intensity Proton Rings

linac, proton, injection, space-charge

15

Y. Yamazaki
FRIB, East Lansing, Michigan, USA

Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
High-intensity, pulsed proton accelerators have been and will be requested by a wide variety of scientific fields and industrial and medical applications, for example, pulsed spallation neutron sources and neutrino sources. We will focus our discussion on the proton rings with a pulse length of a few μsec and a beam power of MW. These accelerators may be used for boosting injectors to higher-energy accelerators, like a neutrino factories. At first, we will discuss on the space-charge force which limit the stored charges in a ring together with the negative-ion injection scheme. The pulsed spallation neutron sources are classified into two schemes. One is the combination of a full-energy linac and an accumulation ring (AR) exemplified by SNS and LANSCE. The other is that of a low-energy linac and a Rapid-Cycle Synchrotron (RCS) exemplified by J-PARC RCS and ISIS. In general, pros and cons of accelerator schemes are dependent upon the technological development results. Pros and cons of AR versus RCS will be discussed on the basis of recent technological developments and beam experiment data together with the future perspectives for MW-class machines.

Slides MOI1B02 [3.850 MB]

MOI1B03

Technical Challenges in Multi-MW Proton Linacs

linac, rfq, cryomodule, proton

20

V.A. Lebedev
Fermilab, Batavia, USA

The intensity frontier research is an important part of modern elementary particle physics. It uses proton beams to create secondary beams consisting of, but not necessary limited to, neutrinos, muons, kaons and neutrons. Deferent experiments require different time structure of proton beams but all of them require the beam power of about or exceeding 1 MW. In addition, powerful proton linacs can find an application in accelerator driven nuclear reactors and transmutation of radioactive waste. Recent advances in the superconducting RF technology make a multi-MW power level economically acceptable. This paper discusses main physics and technical limitations determining ultimate parameters of such accelerators, their structure and performance.

Slides MOI1B03 [2.863 MB]

MOP209

High Intensity Proton FFAG Ring with Serpentine Acceleration for ADS

proton, closed-orbit, transverse-dynamics, injection

60

E. Yamakawa, Y. Ishi, Y. Kuriyama, J.-B. Lagrange, Y. Mori, T. Uesugi
Kyoto University, Research Reactor Institute, Osaka, Japan

In order to produce high intensity proton beam for ADS, a new type of fixed rf acceleration scheme, so-called serpentine acceleration, is examined in scaling FFAG. Longitudinal hamiltonian for scaling FFAG is first derived analytically. Then the features of serpentine acceleration in longitudinal phase space are studied. Ring design for ADS is finally shown.

MOP210

Beam Stacking for High Intensity Pulsed Proton Beam with FFAG

simulation, extraction, neutron, injection

64

Y. Mori, Y. Ishi, Y. Kuriyama, J.-B. Lagrange, T. Uesugi
Kyoto University, Research Reactor Institute, Osaka, Japan

Multi-beam stacking scheme to generate an intense short-pulsed proton beam with high repetition proton FFAG is presented.

MOP216

The Design Study on the Longitudinal Beam Dynamics for CSNS/RCS

injection, simulation, space-charge, bunching

89

N. Wang, M.Y. Huang, Y. Li, S. Wang, S.Y. Xu, Y.S. Yuan
IHEP, Beijing, People's Republic of China

Rapid Cycling Synchrotron (RCS) is the key part of China Spallation Neutron Source (CSNS) accelerators. The RCS accumulates and accelerates 80 MeV beam from linac to 1.6 GeV. The particle number is 1.56·10¹³ for each pulse, with repetition rate of 25 Hz. In the RCS, longitudinal beam dynamics plays a crucial role in achieving high intensity beam with low beam loss. Longitudinal parameters are studied and optimized for efficient RF trapping of the beam in the longitudinal phase space. Beam performance is investigated by particle tracking simulations. Beam dynamic issues related to the high order mode induced by the RF generator are studied with a new developed code. Primary study on the adoption of dual harmonic cavity for higher beam power is also addressed.

MOP255

Acceleration in Vertical Orbit Excursion FFAGs with Edge Focussing

space-charge, proton, simulation, injection

197

S.J. Brooks
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

FFAGs with vertical orbit excursion (VFFAGs) provide a promising alternative design for rings with fixed-field superconducting magnets. They have a vertical magnetic field component that increases with height in the vertical aperture, yielding a skew quadrupole focussing structure. Edge focussing can provide an alternating gradient within each magnet, thus reducing the ring circumference. Like spiral scaling horizontal FFAGs (but not non-scaling ones) the machine has fixed tunes and no intrinsic limitation on momentum range. Rings to accelerate the 800MeV beam from the ISIS proton synchrotron are investigated, in terms of both magnet field geometry and longitudinal behaviour during acceleration with space charge. The 12GeV ring produces an output power of at least 2.18MW.

TUO1C05

Measurements and Interpretation of the Betatron Tune Spectra of High Intensity Bunched Beam at SIS-18

space-charge, synchrotron, ion, injection

310

R. Singh, O. Chorniy, P. Forck, R. Haseitl, W. Kaufmann, P. Kowina, K. Lang
GSI, Darmstadt, Germany
O. Boine-Frankenheim, R. Singh, T. Weiland
TEMF, TU Darmstadt, Darmstadt, Germany

The paper presents the status of the transverse tune measurements in the synchrotron SIS18 at GSI. Presently, there are two systems for tune measurements in operation in the SIS18, namely TOPOS (Tune, Orbit and POsition measurement System) and BBQ (Base Band tune measurement system). The first one is a digital system where the BPM signal is digitized and the bunch position is calculated numerically. The second system is an analog system, where the transverse bunch motion is detected using peak detector. Band limited noise and chirp excitations were used to excite the betatron oscillations. Measurements of the betatron tune spectra were done at injection energy at medium and high intensities. In the frequency spectra a number of peaks around the position of betatron tune were seen. The peaks can be attributed to different bunch head-tail modes which were observed in time domain. These modes were dependent on the beam intensity. In this paper we compare the tune spectra measured at high beam intensity with the theoretical model for the space charge affected head-tail modes.

Slides TUO1C05 [1.315 MB]

THO1A03

Dual-harmonic Acceleration Studies at CSNS RCS

injection, simulation, bunching, cavity

487

J.F. Chen, J.Y. Tang, X. Zhang
IHEP, Beijing, People's Republic of China

Dual harmonic acceleration is proposed to alleviate the space charge effects in the RCS (Rapid Cycling Synchrotron) at the upgrading stages of the CSNS (China Spallation Neutron Source). Different dual harmonic acceleration schemes have been studied by using a self-made parameter calculation code - RAMADH and the simulation code - ORBIT. Both complete and partial coverage of the dual harmonic RF system along the acceleration have been considered. The injection by combining beam chopping and off-momentum is used in the macro-particle tracking simulations by ORBIT. In addition, a new idea that unlocks the RF frequency and the magnetic field in the injection period is found very useful in obtaining a good longitudinal painting.

Slides THO1A03 [1.343 MB]

THO1C02

Beam Loss Control in the ISIS Accelerator Facility

injection, synchrotron, controls, proton

560

D.J. Adams, B. Jones, A.H. Kershaw, S.J. Payne, B.G. Pine, H. V. Smith, C.M. Warsop, R.E. Williamson, M. Wright
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

The ISIS spallation neutron and muon source has been in operation since 1984. The accelerator complex consists of an H⁻ ion source, RFQ, 70 MeV linac, 800 MeV proton synchrotron and associated beam lines. The facility currently delivers ~2.8·10¹³ protons per pulse at 50 Hz, splitting the pulses 40/10 between two neutron target stations. High intensity performance and operation are dominated by the need to control beam loss, which is key to sustainable machine operation and hands on maintenance. Beam loss measurement systems on ISIS are described, along with typical operational levels. The dominant beam loss in the facility occurs in the synchrotron due to high intensity effects during the H⁻ injection and longitudinal trapping processes. These losses are localised in a single superperiod using a beam collector system. Emittance growth during acceleration also drives extraction and beam transport loss at 800 MeV. Measurements, simulation and correction systems for these processes are discussed, as are the implications for further intensity upgrades.

Slides THO1C02 [4.759 MB]

THO1C06

Recent Commissioning of High-intensity Proton Beams in J-PARC Main Ring

beam-losses, injection, proton, kicker

575

Y. Sato, K. Hara, Y. Hashimoto, Y. Hori, S. Igarashi, K. Ishii, N. Kamikubota, T. Koseki, Y. Kurimoto, K. Niki, K. Ohmi, C. Ohmori, M. Okada, M. Shimamoto, M.J. Shirakata, T. Sugimoto, J. Takano, M. Tejima, T. Toyama, M. Uota, S. Yamada, N. Yamamoto, M. Yoshii
KEK, Ibaraki, Japan
S. Hatakeyama, H. Hotchi, F. Tamura
JAEA/J-PARC, Tokai-mura, Japan
S. Nakamura, K. Satou
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

J-PARC main ring (MR) provides high power proton beams of 200 kW to the neutrino experiment. Beam losses were well managed within capacity of collimation system. Since this beam power was achieved by shortening the repetition rate, following tunings had been applied in order to reduce the beam losses, such as improvement of tune flatness, chromaticity correction, upgrades of injection kickers, dynamic bunch-by-bunch feed-back to suppress transverse oscillation, beam loading compensation using feed-forward technique, and balancing the collimators of MR and the injection beam transport line. The dynamic bunch-by-bunch feed-back was effective to reduce the beam losses to one-tenth during injection and beginning of acceleration. With the beam loading compensation, impedance seen by the beam was significantly reduced, longitudinal oscillations were damped, and the beam power was increased over 5% without increasing the beam losses. Monitors were upgraded to find time structure and location of the beam losses, even in first several turns after each injection. In this presentation these commissioning procedures and beam dynamics simulations are shown, and our upgrade plan is discussed.

Slides THO1C06 [2.193 MB]

THO3C04

Longitudinal Beam Diagnosis with RF Chopper System

cavity, linac, neutron, DTL

591

T. Maruta
JAEA/J-PARC, Tokai-mura, Japan
M. Ikegami
KEK, Ibaraki, Japan

J-PARC linac has a chopper system between RFQ and DTL, which utilizes an RF deflector cavity instead of a usual slow wave kicker. Taking advantage of this unique feature of the chopper system, we have experimentally measured the longitudinal full width of phase direction at the chopper cavity. In this presentation, I would like to discuss the measurement technique and measurement results.

Slides THO3C04 [2.495 MB]