HB2012 - List of Keywords (extraction)

Paper	Title	Other Keywords	Page
MOI1A02	J-PARC Recovery Status	linac, status, kicker, vacuum	6
	K. Yamamoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	J-PARC facilities were seriously damaged by the Great East Japan Earthquake in March 2011, but all facilities resumed a beam operation from December 2012. We report the operation status of J-PARC accelerators after the earthquake.
	Slides MOI1A02 [12.726 MB]

MOP210	Beam Stacking for High Intensity Pulsed Proton Beam with FFAG	acceleration, simulation, 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.

MOP247	Beam Stability and Tail Population at SPS Scrapers	emittance, injection, controls, diagnostics	166
	L.N. Drøsdal, K. Cornelis, B. Goddard, V. Kain, M. Meddahi, O. Mete, B. Mikulec, E. Veyrunes CERN, Geneva, Switzerland
	Before injection into the LHC the beams are scraped in the SPS to remove the tails of the transverse particle distributions. Without scraping the tail population is large enough to create losses above the beam abort thresholds of the LHC beam loss monitor system when injecting. The scrapers are only effective if correctly set up. This paper shows the results of periodical scraper scans. The beam position and beam size at the scraper is changing with time. The scraper settings hence need to follow accordingly. The scans also give insight into the transverse tail population and could therefore provide useful beam quality diagnostics. The impact on new scraper designs and setting up strategy are discussed.

MOP248	Brightness Evolution for LHC Beams during the 2012 Run	emittance, brightness, injection, luminosity	170
	M. Kuhn Uni HH, Hamburg, Germany G. Arduini, J.F. Comblin, A. Guerrero, V. Kain, B. Mikulec, F. Roncarolo, M. Sapinski, M. Schaumann, R. Steerenberg CERN, Geneva, Switzerland
	One of the reasons for the remarkable achievements of the LHC is the excellent performance of the LHC injector chain. The evolution of the brightness in the injectors and at LHC collision in 2011 and 2012 is discussed. During certain run periods, the brightness from the beam provided by the injectors was lower than usual. Some of the issues have been identified so far and will be reported. The latest results on emittance blow-up investigations through the 2012 LHC cycle will also be presented and compared to the 2011 data. Possible implications for LHC upgrade scenarios will be mentioned.

MOP258	Simulation of Intense Proton Beams in Novel Isochronous FFAG Designs	space-charge, lattice, cyclotron, simulation	211
	S.L. Sheehy STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom M. Berz, K. Makino MSU, East Lansing, Michigan, USA C. Johnstone Fermilab, Batavia, USA P. Snopok Illinois Institute of Technology, Chicago, Illinois, USA
	Recent developments in the design of non-scaling fixed field alternating gradient (FFAG) accelerators have been focused on achieving isochronous behavior with a small betatron tune excursion. These advances are particularly interesting for applications requiring CW beams, such as Accelerator Driven Systems for energy generation or waste transmutation. The latest advances in lattice design have resulted in a 330 MeV to 1 GeV lattice, isochronous to better than ± 1 percent. This paper reports on simulations of recent lattice designs incorporating 3D space charge effects.

TUO1A01	The High Intensity/High Brightness Upgrade Program at CERN: Status and Challenges	linac, injection, emittance, space-charge	226
	S.S. Gilardoni, G. Arduini, T. Argyropoulos, S. Aumon, H. Bartosik, E. Benedetto, N. Biancacci, T. Bohl, J. Borburgh, C. Carli, F. Caspers, H. Damerau, J. Esteban Müller, V. Forte, R. Garoby, M. Giovannozzi, B. Goddard, S. Hancock, K. Hanke, A. Huschauer, G. Iadarola, M. Meddahi, G. Métral, B. Mikulec, E. Métral, Y. Papaphilippou, S. Persichelli, G. Rumolo, B. Salvant, F. Schmidt, E.N. Shaposhnikova, R. Steerenberg, G. Sterbini, M. Taborelli, H. Timko, M. Vretenar, R. Wasef, C. Yin Vallgren, C. Zannini CERN, Geneva, Switzerland G. Franchetti GSI, Darmstadt, Germany M. Migliorati University of Rome "La Sapienza", Rome, Italy A.Y. Molodozhentsev J-PARC, KEK & JAEA, Ibaraki-ken, Japan M.T.F. Pivi SLAC, Menlo Park, California, USA V.G. Vaccaro Naples University Federico II, Mathematical, Physical and Natural Sciences Faculty, Napoli, Italy
	The future beam brilliance and intensities required by the HL-LHC (High-Luminosity LHC) project and for possible new neutrino production beams triggered a deep revision of the LHC injector performances. The analysis, progressing in the framework of the LHC Injectors Upgrade (LIU) projects, outlined major limitations mainly related to collective effects - space charge in PSB and PS, electron cloud driven and TMCI instabilities in the SPS, longitudinal coupled bunch instabilities in the PS for example - but also to the existing hardware capability to cope with beam instabilities and losses. A summary of the observations and simulation studies carried out so far, as well as the future ones, will be presented. The solution proposed to overcome the different limitations and the plans for their implementation will be also briefly reviewed.
	Slides TUO1A01 [12.748 MB]

TUO1B01	Beam Loss Due to Foil Scattering in the SNS Accumulator Ring	scattering, injection, proton, collimation	254
	J.A. Holmes, M.A. Plum ORNL, Oak Ridge, Tennessee, USA
	Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725. The Spallation Neutron Source is now operating in production mode at about 1 MW of beam power on target, which corresponds to more than 10¹⁴ protons per pulse at 60 Hz with energies exceeding 900 MeV. Although overall beam losses in production tune are low, the highest losses in the entire machine occur in the region downstream of the ring injection stripper foil. In order to better understand the contribution of scattering from the primary stripper foil to losses in the SNS ring, we have carried out calculations using the ORBIT Code aimed at evaluating these losses. These calculations indicate that the probability of beam loss within one turn following a foil hit is ~1.7·10^-8*T, where T is the foil thickness in g/cm², assuming a carbon foil. Thus, for a stripper foil of thickness T = 390 g/cm², the probability of loss within one turn of a foil hit is ~6.7·10^-6. This paper describes the calculations used to arrive at this result, presents the distribution of these losses around the SNS ring, and compares the the calculated loss distribution with that observed experimentally.
	Slides TUO1B01 [2.174 MB]

TUO3C06	The Result of Beam Commissioning in J-PARC 3-GeV RCS	injection, lattice, collimation, scattering	339
	H. Harada, N. Hayashi, H. Hotchi, M. Kinsho, P.K. Saha, Y. Shobuda, F. Tamura, K. Yamamoto, M. Yamamoto, M. Yoshimoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan Y. Irie, T. Koseki, Y. Sato, K. Satou, M.J. Shirakata KEK, Ibaraki, Japan S. Kato Tohoku University, Graduate School of Science, Sendai, Japan
	J-PARC 3-GeV RCS has started the beam commissioning since Oct. 2007. In the beam commissioning, the beam tuning for basic parameters and high-intensity operation has been continuously performed. This presentation will describe the results of the beam-loss reduction and minimization for high-intensity operation.
	Slides TUO3C06 [7.753 MB]

WEO1A03	Resistive Wall Instability in CSNS/RCS	impedance, simulation, injection, wakefield	354
	L. Huang, Y.D. Liu, S. Wang IHEP, Beijing, People's Republic of China
	Rapid Cycling Synchrotron (RCS) of the China Spallation Neutron Source (CSNS) is a high intensity proton accelerator, with average beam power of 100kW. The collective effects caused by the coupling impedance may be the limit to beam power. The impedance estimation for components on beam line shows that the resistive wall impedance and its instability are more serious than any others. Based on the impedance budget, the instability is theoretically estimated. A simple resistive wall wake field model is used to simulate the bunch oscillation and obtain the growth time. In this simulation model, the continuous resistive wall wake field is concentrated to one position in the ring and the long bunch is sliced into many micro-bunches. By tracking the dynamics of the macro-bunches, the transverse growth time are obtained. The simulation results are also confirmed the restriction to instability by natural chromaticity. # Supported by National Natural Science Foundation of China (11175193) *wangs@ihep.ac.cn
	Slides WEO1A03 [1.358 MB]

WEO3A03	Extraction, Transport and Collimation of the PSI 1.3 MW Proton Beam	target, proton, cyclotron, neutron	373
	D. Reggiani PSI, Villigen PSI, Switzerland
	With an average operating beam power of 1.3 MW the PSI proton accelerator complex is currently leading the race towards the high intensity frontier of particle accelerators. This talk gives an overview of the extraction of the 590 MeV beam from the ring cyclotron and its low loss transport to the meson production targets M and E as well as to the SINQ spallation neutron source. Particular regard is given to the collimator system reshaping the beam which leaves the 40 mm thick graphite target E before reaching SINQ. Since 2011, up to 8 second long beam macro-pulses are regularly diverted to the new UCN spallation source by means of a fast kicker magnet. The switchover from the SINQ to the UCN beam line as well as the smooth beam transport up to the UCN spallation target constitute the subject of the last part of the talk.
	Slides WEO3A03 [2.728 MB]

WEO3A04	Current and Planned High Proton Flux Operations at the FNAL Booster	booster, proton, kicker, radiation	378
	F.G.G. Garcia, W. Pellico Fermilab, Batavia, USA
	Funding: Department of Energy - Office of High Energy Physics The Fermi Lab Proton Source has seen a dramatic increase in requested flux this past decade. An increase of over ten fold in hourly flux was necessary to meet the FNAL HEP experimental requirements. This next decade will be just as challenging as the lab's HEP planning will again require the Proton Source to double the hourly flux. The recent achievements were accomplished with major upgrades such a collimation system, new correctors and aperture improvements. To achieve the next level of proton delivery rates will require even more improvements. A five year Proton Improvement Plan (PIP) is currently underway with a goal to maintain 2012 activation levels while doubling the hourly flux. Tasks in the PIP to help reduce losses include an improved beam notching system, cogging, aperture improvement and beam emittances control and reduction. This talk will describe current conditions and plans to mitigate losses with the planned increase in proton throughput.
	Slides WEO3A04 [8.309 MB]

WEO1B01	Low Gamma Transition Optics for the SPS: Simulation and Experimental Results for High Brightness Beams	optics, emittance, injection, electron	381
	H. Bartosik, G. Arduini, T. Argyropoulos, T. Bohl, K. Cornelis, J. Esteban Müller, K.S.B. Li, Y. Papaphilippou, G. Rumolo, B. Salvant, F. Schmidt, E.N. Shaposhnikova, H. Timko CERN, Geneva, Switzerland A.Y. Molodozhentsev KEK, Ibaraki, Japan
	The single bunch transverse mode coupling instability (TMCI) at injection is presently one of the main intensity limitation for LHC beams in the SPS. A new optics for the SPS with lower transition energy yields an almost 3-fold increase of the slip factor at injection energy and thus a significantly higher TMCI threshold, as demonstrated both in simulations and in experimental studies. It is observed furthermore that the low gamma transition optics yields better longitudinal stability throughout the entire acceleration cycle. In addition, simulations predict a higher threshold for the electron cloud driven single bunch instability, which might become an important limitation for high intensity LHC beams with the nominal 25 ns bunch spacing. This contribution gives a summary of the experimental and simulation studies, addressing also space charge effects and the achievable brightness with high intensity single bunch beams.

WEO1C04	Acceleration of High-Intensity Protons in the J-PARC Synchrotrons	synchrotron, cavity, injection, proton	444
	M. Yoshii KEK/JAEA, Ibaraki-Ken, Japan
	The J-PARC consisting of the 181 MeV Linac, the 3GeV rapid cycling synchrotron (RCS) and the 50 GeV main synchrotron (MR), is the first high intensity proton synchrotron facility to use the high field gradient magnetic alloy (MA) loaded accelerating cavity. MA is a low-Q material. However, because of the high permeability and the high saturation magnetic flux density, the MA cores are the only materials to realize the required gradient. The MA loaded cavity can be considered as a stable passive load. No tuning control is necessary. 11 RF systems are installed in the RCS, and 8 RF systems in the MR. In addition, the RCS RF systems are operated in a dual harmonic mode to perform the acceleration and the longitudinal manipulation of the high intensity beam in the RCS available space. Beam loading compensation is an important issue. The feed-forward method using the RF beam signals from the wall current monitor has been established. The J-PARC synchrotrons realize stable, reproducible and clean acceleration of high intensity protons. A transition-free lattice and a precise digital timing system asynchronous to the AC-line are the distinctive features, which enable this achievement.
	Slides WEO1C04 [3.861 MB]

THO1C01	High Intensity Operation and Control of Beam Losses in a Cyclotron Based Accelerator	cyclotron, target, proton, neutron	555
	M. Seidel, J. Grillenberger, A.C. Mezger PSI, Villigen PSI, Switzerland
	This presentation discusses aspects of high intensity operation in PSI's cyclotron based proton accelerator (HIPA). Major beam loss mechanisms and tuning methods to minimize losses are presented. Concept and optimization of low loss beam extraction from a cyclotron are described. Collimators are used to localize beam losses and activation. Activation levels of accelerator components are shown. An overview on instrumentation for loss monitoring and prevention of failure situations is given. Other relevant aspects include the beam trip statistics and grid to beam power conversion efficiency.
	Slides THO1C01 [3.642 MB]

Paper

Title

Other Keywords

Page

MOI1A02

J-PARC Recovery Status

linac, status, kicker, vacuum

6

K. Yamamoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

J-PARC facilities were seriously damaged by the Great East Japan Earthquake in March 2011, but all facilities resumed a beam operation from December 2012. We report the operation status of J-PARC accelerators after the earthquake.

Slides MOI1A02 [12.726 MB]

MOP210

Beam Stacking for High Intensity Pulsed Proton Beam with FFAG

acceleration, simulation, 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.

MOP247

Beam Stability and Tail Population at SPS Scrapers

emittance, injection, controls, diagnostics

166

L.N. Drøsdal, K. Cornelis, B. Goddard, V. Kain, M. Meddahi, O. Mete, B. Mikulec, E. Veyrunes
CERN, Geneva, Switzerland

Before injection into the LHC the beams are scraped in the SPS to remove the tails of the transverse particle distributions. Without scraping the tail population is large enough to create losses above the beam abort thresholds of the LHC beam loss monitor system when injecting. The scrapers are only effective if correctly set up. This paper shows the results of periodical scraper scans. The beam position and beam size at the scraper is changing with time. The scraper settings hence need to follow accordingly. The scans also give insight into the transverse tail population and could therefore provide useful beam quality diagnostics. The impact on new scraper designs and setting up strategy are discussed.

MOP248

Brightness Evolution for LHC Beams during the 2012 Run

emittance, brightness, injection, luminosity

170

M. Kuhn
Uni HH, Hamburg, Germany
G. Arduini, J.F. Comblin, A. Guerrero, V. Kain, B. Mikulec, F. Roncarolo, M. Sapinski, M. Schaumann, R. Steerenberg
CERN, Geneva, Switzerland

One of the reasons for the remarkable achievements of the LHC is the excellent performance of the LHC injector chain. The evolution of the brightness in the injectors and at LHC collision in 2011 and 2012 is discussed. During certain run periods, the brightness from the beam provided by the injectors was lower than usual. Some of the issues have been identified so far and will be reported. The latest results on emittance blow-up investigations through the 2012 LHC cycle will also be presented and compared to the 2011 data. Possible implications for LHC upgrade scenarios will be mentioned.

MOP258

Simulation of Intense Proton Beams in Novel Isochronous FFAG Designs

space-charge, lattice, cyclotron, simulation

211

S.L. Sheehy
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
M. Berz, K. Makino
MSU, East Lansing, Michigan, USA
C. Johnstone
Fermilab, Batavia, USA
P. Snopok
Illinois Institute of Technology, Chicago, Illinois, USA

Recent developments in the design of non-scaling fixed field alternating gradient (FFAG) accelerators have been focused on achieving isochronous behavior with a small betatron tune excursion. These advances are particularly interesting for applications requiring CW beams, such as Accelerator Driven Systems for energy generation or waste transmutation. The latest advances in lattice design have resulted in a 330 MeV to 1 GeV lattice, isochronous to better than ± 1 percent. This paper reports on simulations of recent lattice designs incorporating 3D space charge effects.

TUO1A01

The High Intensity/High Brightness Upgrade Program at CERN: Status and Challenges

linac, injection, emittance, space-charge

226

S.S. Gilardoni, G. Arduini, T. Argyropoulos, S. Aumon, H. Bartosik, E. Benedetto, N. Biancacci, T. Bohl, J. Borburgh, C. Carli, F. Caspers, H. Damerau, J. Esteban Müller, V. Forte, R. Garoby, M. Giovannozzi, B. Goddard, S. Hancock, K. Hanke, A. Huschauer, G. Iadarola, M. Meddahi, G. Métral, B. Mikulec, E. Métral, Y. Papaphilippou, S. Persichelli, G. Rumolo, B. Salvant, F. Schmidt, E.N. Shaposhnikova, R. Steerenberg, G. Sterbini, M. Taborelli, H. Timko, M. Vretenar, R. Wasef, C. Yin Vallgren, C. Zannini
CERN, Geneva, Switzerland
G. Franchetti
GSI, Darmstadt, Germany
M. Migliorati
University of Rome "La Sapienza", Rome, Italy
A.Y. Molodozhentsev
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
M.T.F. Pivi
SLAC, Menlo Park, California, USA
V.G. Vaccaro
Naples University Federico II, Mathematical, Physical and Natural Sciences Faculty, Napoli, Italy

The future beam brilliance and intensities required by the HL-LHC (High-Luminosity LHC) project and for possible new neutrino production beams triggered a deep revision of the LHC injector performances. The analysis, progressing in the framework of the LHC Injectors Upgrade (LIU) projects, outlined major limitations mainly related to collective effects - space charge in PSB and PS, electron cloud driven and TMCI instabilities in the SPS, longitudinal coupled bunch instabilities in the PS for example - but also to the existing hardware capability to cope with beam instabilities and losses. A summary of the observations and simulation studies carried out so far, as well as the future ones, will be presented. The solution proposed to overcome the different limitations and the plans for their implementation will be also briefly reviewed.

Slides TUO1A01 [12.748 MB]

TUO1B01

Beam Loss Due to Foil Scattering in the SNS Accumulator Ring

scattering, injection, proton, collimation

254

J.A. Holmes, M.A. Plum
ORNL, Oak Ridge, Tennessee, USA

Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725.
The Spallation Neutron Source is now operating in production mode at about 1 MW of beam power on target, which corresponds to more than 10¹⁴ protons per pulse at 60 Hz with energies exceeding 900 MeV. Although overall beam losses in production tune are low, the highest losses in the entire machine occur in the region downstream of the ring injection stripper foil. In order to better understand the contribution of scattering from the primary stripper foil to losses in the SNS ring, we have carried out calculations using the ORBIT Code aimed at evaluating these losses. These calculations indicate that the probability of beam loss within one turn following a foil hit is ~1.7·10^-8*T, where T is the foil thickness in g/cm², assuming a carbon foil. Thus, for a stripper foil of thickness T = 390 g/cm², the probability of loss within one turn of a foil hit is ~6.7·10^-6. This paper describes the calculations used to arrive at this result, presents the distribution of these losses around the SNS ring, and compares the the calculated loss distribution with that observed experimentally.

Slides TUO1B01 [2.174 MB]

TUO3C06

The Result of Beam Commissioning in J-PARC 3-GeV RCS

injection, lattice, collimation, scattering

339

H. Harada, N. Hayashi, H. Hotchi, M. Kinsho, P.K. Saha, Y. Shobuda, F. Tamura, K. Yamamoto, M. Yamamoto, M. Yoshimoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
Y. Irie, T. Koseki, Y. Sato, K. Satou, M.J. Shirakata
KEK, Ibaraki, Japan
S. Kato
Tohoku University, Graduate School of Science, Sendai, Japan

J-PARC 3-GeV RCS has started the beam commissioning since Oct. 2007. In the beam commissioning, the beam tuning for basic parameters and high-intensity operation has been continuously performed. This presentation will describe the results of the beam-loss reduction and minimization for high-intensity operation.

Slides TUO3C06 [7.753 MB]

WEO1A03

Resistive Wall Instability in CSNS/RCS

impedance, simulation, injection, wakefield

354

L. Huang, Y.D. Liu, S. Wang
IHEP, Beijing, People's Republic of China

Rapid Cycling Synchrotron (RCS) of the China Spallation Neutron Source (CSNS) is a high intensity proton accelerator, with average beam power of 100kW. The collective effects caused by the coupling impedance may be the limit to beam power. The impedance estimation for components on beam line shows that the resistive wall impedance and its instability are more serious than any others. Based on the impedance budget, the instability is theoretically estimated. A simple resistive wall wake field model is used to simulate the bunch oscillation and obtain the growth time. In this simulation model, the continuous resistive wall wake field is concentrated to one position in the ring and the long bunch is sliced into many micro-bunches. By tracking the dynamics of the macro-bunches, the transverse growth time are obtained. The simulation results are also confirmed the restriction to instability by natural chromaticity.
# Supported by National Natural Science Foundation of China (11175193)
*wangs@ihep.ac.cn

Slides WEO1A03 [1.358 MB]

WEO3A03

Extraction, Transport and Collimation of the PSI 1.3 MW Proton Beam

target, proton, cyclotron, neutron

373

D. Reggiani
PSI, Villigen PSI, Switzerland

With an average operating beam power of 1.3 MW the PSI proton accelerator complex is currently leading the race towards the high intensity frontier of particle accelerators. This talk gives an overview of the extraction of the 590 MeV beam from the ring cyclotron and its low loss transport to the meson production targets M and E as well as to the SINQ spallation neutron source. Particular regard is given to the collimator system reshaping the beam which leaves the 40 mm thick graphite target E before reaching SINQ. Since 2011, up to 8 second long beam macro-pulses are regularly diverted to the new UCN spallation source by means of a fast kicker magnet. The switchover from the SINQ to the UCN beam line as well as the smooth beam transport up to the UCN spallation target constitute the subject of the last part of the talk.

Slides WEO3A03 [2.728 MB]

WEO3A04

Current and Planned High Proton Flux Operations at the FNAL Booster

booster, proton, kicker, radiation

378

F.G.G. Garcia, W. Pellico
Fermilab, Batavia, USA

Funding: Department of Energy - Office of High Energy Physics
The Fermi Lab Proton Source has seen a dramatic increase in requested flux this past decade. An increase of over ten fold in hourly flux was necessary to meet the FNAL HEP experimental requirements. This next decade will be just as challenging as the lab's HEP planning will again require the Proton Source to double the hourly flux. The recent achievements were accomplished with major upgrades such a collimation system, new correctors and aperture improvements. To achieve the next level of proton delivery rates will require even more improvements. A five year Proton Improvement Plan (PIP) is currently underway with a goal to maintain 2012 activation levels while doubling the hourly flux. Tasks in the PIP to help reduce losses include an improved beam notching system, cogging, aperture improvement and beam emittances control and reduction. This talk will describe current conditions and plans to mitigate losses with the planned increase in proton throughput.

Slides WEO3A04 [8.309 MB]

WEO1B01

Low Gamma Transition Optics for the SPS: Simulation and Experimental Results for High Brightness Beams

optics, emittance, injection, electron

381

H. Bartosik, G. Arduini, T. Argyropoulos, T. Bohl, K. Cornelis, J. Esteban Müller, K.S.B. Li, Y. Papaphilippou, G. Rumolo, B. Salvant, F. Schmidt, E.N. Shaposhnikova, H. Timko
CERN, Geneva, Switzerland
A.Y. Molodozhentsev
KEK, Ibaraki, Japan

The single bunch transverse mode coupling instability (TMCI) at injection is presently one of the main intensity limitation for LHC beams in the SPS. A new optics for the SPS with lower transition energy yields an almost 3-fold increase of the slip factor at injection energy and thus a significantly higher TMCI threshold, as demonstrated both in simulations and in experimental studies. It is observed furthermore that the low gamma transition optics yields better longitudinal stability throughout the entire acceleration cycle. In addition, simulations predict a higher threshold for the electron cloud driven single bunch instability, which might become an important limitation for high intensity LHC beams with the nominal 25 ns bunch spacing. This contribution gives a summary of the experimental and simulation studies, addressing also space charge effects and the achievable brightness with high intensity single bunch beams.

WEO1C04

Acceleration of High-Intensity Protons in the J-PARC Synchrotrons

synchrotron, cavity, injection, proton

444

M. Yoshii
KEK/JAEA, Ibaraki-Ken, Japan

The J-PARC consisting of the 181 MeV Linac, the 3GeV rapid cycling synchrotron (RCS) and the 50 GeV main synchrotron (MR), is the first high intensity proton synchrotron facility to use the high field gradient magnetic alloy (MA) loaded accelerating cavity. MA is a low-Q material. However, because of the high permeability and the high saturation magnetic flux density, the MA cores are the only materials to realize the required gradient. The MA loaded cavity can be considered as a stable passive load. No tuning control is necessary. 11 RF systems are installed in the RCS, and 8 RF systems in the MR. In addition, the RCS RF systems are operated in a dual harmonic mode to perform the acceleration and the longitudinal manipulation of the high intensity beam in the RCS available space. Beam loading compensation is an important issue. The feed-forward method using the RF beam signals from the wall current monitor has been established. The J-PARC synchrotrons realize stable, reproducible and clean acceleration of high intensity protons. A transition-free lattice and a precise digital timing system asynchronous to the AC-line are the distinctive features, which enable this achievement.

Slides WEO1C04 [3.861 MB]

THO1C01

High Intensity Operation and Control of Beam Losses in a Cyclotron Based Accelerator

cyclotron, target, proton, neutron

555

M. Seidel, J. Grillenberger, A.C. Mezger
PSI, Villigen PSI, Switzerland

This presentation discusses aspects of high intensity operation in PSI's cyclotron based proton accelerator (HIPA). Major beam loss mechanisms and tuning methods to minimize losses are presented. Concept and optimization of low loss beam extraction from a cyclotron are described. Collimators are used to localize beam losses and activation. Activation levels of accelerator components are shown. An overview on instrumentation for loss monitoring and prevention of failure situations is given. Other relevant aspects include the beam trip statistics and grid to beam power conversion efficiency.

Slides THO1C01 [3.642 MB]