HB2012 - List of Keywords (electron)

Paper	Title	Other Keywords	Page
MOP213	Beam Losses due to the Foil Scattering for CSNS/RCS	beam-losses, scattering, injection, proton	78
	M.Y. Huang, N. Wang, S. Wang, S.Y. Xu IHEP, Beijing, People's Republic of China
	For the Rapid Cycling Synchrotron of China Spallation Neutron Source (CSNS/RCS), the stripping foil scattering generates the beam halo and gives rise to additional beam losses during the injection process. The interaction between the proton beam and the stripping foil was discussed and the foil scattering was studied. A simple model and the realistic situation of the foil scattering were considered. By using the codes ORBIT and FLUKA, the multi-turn phase space painting injection process with the stripping foil scattering for CSNS/RCS was simulated and the beam losses due to the foil scattering were obtained.

MOP252	Measurements of the LHC Longitudinal Resistive Impedance with Beam	impedance, synchrotron, emittance, synchrotron-radiation	183
	J.F. Esteban Müller, T. Argyropoulos, T. Bohl, T. Mastoridis, N. Mounet, G. Papotti, B. Salvant, E.N. Shaposhnikova, D. Valuch CERN, Geneva, Switzerland
	The resistive part of the longitudinal impedance contributes to the heat deposition on different elements in the LHC ring including the beam screens, where it has to be absorbed by the cryogenic system and can be a practical limitation for the maximum beam intensity. In this paper, we present the first measurements of the LHC longitudinal resistive impedance with beam, done through synchronous phase shift measurements during Machine Development sessions in 2012. Synchronous phase shift is measured for different bunch intensities and lengths using the high-precision LHC Beam Phase Module and then data are post-processed to further increase the accuracy. The dependence of the energy loss per particle on bunch length is then obtained and compared with the expected values found using the LHC impedance model.

MOP261	A Test Facility for MEIC ERL Circulator Ring Based Electron Cooler Design	SRF, FEL, cathode, kicker	219
	Y. Zhang, Y.S. Derbenev, D. Douglas, A. Hutton, G.A. Krafft, E.W. Nissen JLAB, Newport News, Virginia, USA
	Funding: * Supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357. An electron cooling facility which is capable to deliver a beam with energy up to 55 MeV and average current up to 1.5 A at a high bunch repetition rate up to 750 MHz is required for MEIC. The present cooler design concept is based on a magnetized photo-cathode SRF gun, an SRF ERL and a compact circulator ring. In this paper, we present a proposal of a test facility utilizing the JLab FEL ERL for a technology demonstration of this cooler design concept. Beam studies will be performed and supporting technologies will also be developed in this test facility

TUO1C01	Recent Developments on High Intensity Beam Diagnostics at SNS	proton, cathode, target, simulation	292
	W. Blokland 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 Ring accumulates 0.6 μs long proton bunches of up to 1.6·10¹⁴ protons with a typical peak current of over 50 A during a 1 ms cycle. To qualify the beam, we perform different transverse profile measurements that can be done at full intensity. The electron beam scanner performs a non-invasive measurement of the transverse and longitudinal profiles of the beam in the ring. Electrons passing over and through the proton beam are deflected and projected on a fluorescent screen. Analysis of the projection yields the transverse profile while multi transverse profiles offset in time yield the longitudinal profile. Progress made with this system will be discussed as well as temperature measurements of the stripping foil and other transverse measurements.
	Slides TUO1C01 [15.498 MB]

WEO3A01	High Energy Electron Cooling	high-voltage, vacuum, gun, controls	363
	V.B. Reva, M.I. Bryzgunov, V.M. Panasyuk, V.V. Parkhomchuk BINP SB RAS, Novosibirsk, Russia
	The electron cooler of a 2 MeV for COSY storage ring FZJ is assembled in BINP. This paper describes the first experimental results from the electron cooler with electron beam and high voltage. The cooling section is designed on the classic scheme of low energy coolers like cooler CSRm, CSRe, LEIR that was produced in BINP before. The electron beam is transported inside the longitudinal magnetic field along whole trajectory from an electron gun to a collector. This optic scheme is stimulated by the wide range of the working energies 0.1(0.025)-2 MeV. The electrostatic accelerator consists of 34 individual unify section. Each section contains two HV power supply (±30 kV) and power supply of the magnetic coils. The electrical power to each section is provided by the cascade transformer. The cascade transformer is the set of the transformer connected in series with isolating winding.
	Slides WEO3A01 [7.902 MB]

WEO1B01	Low Gamma Transition Optics for the SPS: Simulation and Experimental Results for High Brightness Beams	optics, emittance, injection, extraction	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.

WEO1C05	Longitudinal Space Charge Phenomena in an Intense Beam in a Ring	space-charge, induction, focusing, injection	447
	R.A. Kishek, B.L. Beaudoin, D.W. Feldman, I. Haber, T.W. Koeth, Y. Mo UMD, College Park, Maryland, USA
	Funding: Supported by the US Dept. of Energy, Offices of High Energy Physics and Fusion Energy Sciences, and by the US Dept. of Defense, Office of Naval Research and the Joint Technology Office. The University of Maryland Electron Ring (UMER) uses nonrelativistic, high-current electron beams to access the intense space charge dynamics applicable to hadron beams. The UMER beam parameters correspond to space charge incoherent tune shifts, at injection, in the range of 1-5.5 integers. Longitudinal induction focusing is used to counteract the space charge force at the edges of a long rectangular bunch, confining the beam for 100s of turns. We report on two recent findings: (1) The formation and propagation of solitons from large amplitude longitudinal perturbations, observed experimentally and reproduced in WARP* simulations. (2) The evolution of a longitudinal multi-streaming instability when the space-charge force is allowed to lengthen the bunch ends. The expanding bunch ends fill the ring, interpenetrate, and wrap repeatedly, forming multiple streams at any one location, each with its unique velocity. The resulting multi-stream instability is investigated over a wide range of beam currents and initial pulse lengths, and experimental observations are in good agreement with WARP simulations and an analytical theory that successfully predicts the onset of the instability. * D.P. Grote, A. Friedman, I. Haber, S. Yu, Fus. Eng. & Des. 32-33, 193-200 (1996).
	Slides WEO1C05 [5.868 MB]

WEO3C01	Injection and Stripping Foil Studies for a 180 MeV Injection Upgrade at ISIS	injection, simulation, synchrotron, dipole	456
	B. Jones, D.J. Adams, M.C. Hughes, S.J.S. Jago, B.G. Pine, H. V. Smith, C.M. Warsop, R.E. Williamson STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	The Rutherford Appleton Laboratory (RAL) is home to ISIS, the world's most productive spallation neutron source. ISIS has two neutron producing target stations (TS-1 and TS-2), operated at 40 Hz and 10 Hz respectively with a 50 Hz, 800 MeV proton beam from a rapid cycling synchrotron (RCS), which is fed by a 70 MeV H− drift tube linac. The multi-turn charge-exchange injection process used on ISIS has been the subject of a programme of detailed studies in recent years including benchmarked simulations and experiments. More recently, these studies have been expanded as plans for upgrading ISIS have focussed on replacement of the 70 MeV linac with a new, higher energy injector and a new synchrotron injection straight. Whilst much of these studies have been reported elsewhere, this paper presents a summary of the programme with some further details.
	Slides WEO3C01 [4.895 MB]

WEO3C03	Beam Halo Dynamics and Control with Hollow Electron Beams	collimation, collider, emittance, controls	466
	G. Stancari, G. Annala, A. Didenko, T.R. Johnson, I.A. Morozov, V. Previtali, G.W. Saewert, V.D. Shiltsev, D.A. Still, A. Valishev, L.G. Vorobiev Fermilab, Batavia, USA R.W. Aßmann, R. Bruce, S. Redaelli, A. Rossi, B. Salvachua, G. Valentino CERN, Geneva, Switzerland D.N. Shatilov BINP SB RAS, Novosibirsk, Russia
	Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract DE-AC02-07CH11359 with the US Department of Energy. Partial support was provided by the US LHC Accelerator Research Program (LARP). Experimental measurements of beam halo diffusion dynamics with collimator scans are reviewed. The concept of halo control with a hollow electron beam collimator, its demonstration at the Tevatron, and its possible applications at the LHC are discussed.
	Slides WEO3C03 [5.139 MB]

THO1A01	Beam-beam Effects in RHIC	proton, resonance, simulation, emittance	479
	Y. Luo, M. Bai, W. Fischer, C. Montag, S.M. White BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. In this article we will review the beam-beam effects in the Relativistic Heavy Ion Collider (RHIC). We will cover the experimental observations, beam-beam simulation techniques and results, and head-on beam-beam compensation with electron lenses. The next luminosity goal in the RHIC polarized proton operation is to double the luminosity with a higher proton bunch intensity. After the upgrade, the beam-beam parameter will reach 0.03. Head-on beam-beam compensation is aimed to reduce the beam-beam tune spread and non-linear beam-beam resonance driving terms.
	Slides THO1A01 [1.355 MB]

THO1B04	Space Charge Effects in the NICA Collider Rings	ion, collider, luminosity, emittance	522
	O.S. Kozlov, S.A. Kostromin, I.N. Meshkov, A.O. Sidorin, A.V. Smirnov, G.V. Trubnikov JINR, Dubna, Moscow Region, Russia A.V. Eliseev JINR/VBLHEP, Dubna, Moscow region, Russia T. Katayama GSI, Darmstadt, Germany
	Accelerator complex NICA, developed at JINR, will provide an ion-ion (Au⁷⁹⁺) collisions at energies of 1-4.5 GeV/u, as well as experiments on collisions of polarized proton-proton and deuteron-deuteron beams. The calculations of the optical properties of superconducting collider rings have been aimed to create appropriate conditions for the collisions of beams and obtaining the required luminosity parameters in the working range of energies. The collider characteristics and the beam dynamics have been worked out mainly for ion-ion mode of the complex. The main effects limiting luminosity are the space charge dominating at the range of 1-3 GeV/u and the intrabeam scattering dominating for 3-4.5 GeV/u beams. Application of both electron and stochastic cooling methods is essential feature of the project. That allows us to suppress these effects in the corresponding energy ranges.
	Slides THO1B04 [3.938 MB]

THO1B05	Broad-band Transverse Feedback against e-cloud or TMCI: Plan and Status	feedback, controls, kicker, pick-up	527
	C.H. Rivetta, J.M. Cesaratto, J.D. Fox, M.T.F. Pivi, O. Turgut, S. Uemura SLAC, Menlo Park, California, USA W. Höfle, K.S.B. Li CERN, Geneva, Switzerland
	The feedback control of intra-bunch instabilities driven by electron-clouds or strong head-tail coupling (Transverse mode coupled instabilities, TMCI) requires bandwidth sufficient to sense the vertical position and apply multiple corrections within a nanosecond-scale bunch. These requirements impose challenges and limits in the design and implementation of the feedback system. To develop the feedback control prototype, different research areas have been pursed to model and identify the bunch dynamics, design the feedback control and implement the GigaHertz bandwidth hardware. This paper presents those R&D lines and reports on the progress as it stands today. It presents preliminary results of feedback systems stabilizing the transverse intra-bunch motion, based on macro-particle simulation codes (CMAD / HeadTail) and measurement results of the beam motion when it is driven by particular excitation signals.
	Slides THO1B05 [7.197 MB]

THO3B05	Intense High Charge State Heavy Ion Beam Production for the Advanced Accelerators	ion, ion-source, ECRIS, plasma	550
	L.T. Sun IMP, Lanzhou, People's Republic of China
	Modern advanced heavy ion beam accelerators have strong needs for either dc or pulsed intense high charge state heavy ion beams, such as dc beams for FRIB project, SPIRAL2 project, HIRFL/IMP facility, RIBF/RIKEN facility ect, and pulsed beams for RHIC, LHC, FAIR project. After decades' development, only several typical ion sources have found their applications in these accelerators, i.e. ECR ion source, EBIS and LIS or Laser Ion Source. This paper will give a general review of the advantages and limitations of the three types of ion sources. The latest development and performance for the three types of ion sources will be presented.
	Slides THO3B05 [2.464 MB]

THO3C01	Optical Transition Radiation for Non-relativistic Ion Beams	ion, target, photon, radiation	580
	B. Walasek-Höhne, C.A. Andre, F. Becker, P. Forck, A. Reiter, M. Schwickert, R. Singh GSI, Darmstadt, Germany A.H. Lumpkin Fermilab, Batavia, USA
	In this contribution, recent results of Optical Transition Radiation (OTR) measurements with a non-relativistic heavy-ion beam will be presented. This feasibility study was prompted by previous measurements [1] and the theoretical estimation of expected signal strengths for the GSI linear accelerator UNILAC. For this experiment, an 11.4 MeV/u Uranium beam was chosen to investigate OTR signal from several target materials and to evaluate the working regime for the used experimental setup. The OTR light was either observed directly with an Image Intensified CCD camera (ICCD) or indirectly via a spectrometer for wavelength resolved data. A moveable stripping foil allowed measurements with two different ion charge states. The theoretical q2 dependency of the OTR process predicts a six-fold increase in light yield which was confirmed experimentally. Obtained OTR beam profiles were compered to SEM-Grid data. Moreover, ICCD gating feature, as well as the emitted light spectrum ruled out contribution of any background sources with longer emission time constant e.g. blackbody radiation. [1] C. Bal et al., "OTR from Non-relativistic Electrons", Proceedings of DIPAC03, PM04, Mainz Germany.
	Slides THO3C01 [1.905 MB]

THO3C03	Beam Induced Fluorescence - Profile Monitoring for Targets and Transport	vacuum, ion, target, cathode	586
	F. Becker, C.A. Andre, C. Dorn, P. Forck, R. Haseitl, B. Walasek-Höhne GSI, Darmstadt, Germany T. Dandl, T. Heindl, A. Ulrich TUM/Physik, Garching bei München, Germany J. Egberts, T. Papaevangelou CEA, Gif-sur-Yvette, France J. Marroncle CEA/IRFU, Gif-sur-Yvette, France
	Online profile diagnostic is preferred to monitor intense hadron beams at the Facility of Antiproton and Ion Research (FAIR). One instrument for beam profile measurement is the gas based Beam Induced Fluorescence (BIF)-monitor. It relies on the optical fluorescence of residual gas, excited by beam particles. In front of production targets for radioactive ion beams or in plasma physics applications, vacuum constraints are less restrictive and allow a sufficient number of fluorescence photons, even at minimum ionizing energies. Unwanted effects like radiation damage and radiation induced background need to be addressed as well. A profile comparison of BIF and Ionization Profile Monitor (IPM) in nitrogen and rare gases is presented. We studied the BIF method from 10^-3 to 30 mbar with an imaging spectrograph. Preferable fluorescence transitions and fundamental limitations are discussed.
	Slides THO3C03 [7.371 MB]

THO3C05	Fiber Based BLM System Research and Development at CERN	photon, radiation, beam-losses, quadrupole	596
	S. Mallows The University of Liverpool, Liverpool, United Kingdom E.B. Holzer, S. Mallows, J.W. van Hoorne CERN, Geneva, Switzerland
	The application of a beam loss measurement (BLM) system based on Cherenkov light generated in optical fibers to a linear accelerator with long bunch trains is currently under investigation at CERN. In the context of the Compact Linear Collider (CLIC) study, the machine protection role of the BLM system consists of its input to the \lqnext cycle permit\rq. In between two cycles it is determined whether it is safe to commit the machine for the next cycle. A model for light production and propagation has been developed and validated with beam measurements. Monte Carlo simulations of loss scenarios established the suitability in terms of sensitivity and dynamic range. The achievable longitudinal position resolution of the system, considering that the bunch trains and the optical fiber length are comparable in size is discussed.
	Slides THO3C05 [3.846 MB]

Paper

Title

Other Keywords

Page

MOP213

Beam Losses due to the Foil Scattering for CSNS/RCS

beam-losses, scattering, injection, proton

78

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

For the Rapid Cycling Synchrotron of China Spallation Neutron Source (CSNS/RCS), the stripping foil scattering generates the beam halo and gives rise to additional beam losses during the injection process. The interaction between the proton beam and the stripping foil was discussed and the foil scattering was studied. A simple model and the realistic situation of the foil scattering were considered. By using the codes ORBIT and FLUKA, the multi-turn phase space painting injection process with the stripping foil scattering for CSNS/RCS was simulated and the beam losses due to the foil scattering were obtained.

MOP252

Measurements of the LHC Longitudinal Resistive Impedance with Beam

impedance, synchrotron, emittance, synchrotron-radiation

183

J.F. Esteban Müller, T. Argyropoulos, T. Bohl, T. Mastoridis, N. Mounet, G. Papotti, B. Salvant, E.N. Shaposhnikova, D. Valuch
CERN, Geneva, Switzerland

The resistive part of the longitudinal impedance contributes to the heat deposition on different elements in the LHC ring including the beam screens, where it has to be absorbed by the cryogenic system and can be a practical limitation for the maximum beam intensity. In this paper, we present the first measurements of the LHC longitudinal resistive impedance with beam, done through synchronous phase shift measurements during Machine Development sessions in 2012. Synchronous phase shift is measured for different bunch intensities and lengths using the high-precision LHC Beam Phase Module and then data are post-processed to further increase the accuracy. The dependence of the energy loss per particle on bunch length is then obtained and compared with the expected values found using the LHC impedance model.

MOP261

A Test Facility for MEIC ERL Circulator Ring Based Electron Cooler Design

SRF, FEL, cathode, kicker

219

Y. Zhang, Y.S. Derbenev, D. Douglas, A. Hutton, G.A. Krafft, E.W. Nissen
JLAB, Newport News, Virginia, USA

Funding: * Supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357.
An electron cooling facility which is capable to deliver a beam with energy up to 55 MeV and average current up to 1.5 A at a high bunch repetition rate up to 750 MHz is required for MEIC. The present cooler design concept is based on a magnetized photo-cathode SRF gun, an SRF ERL and a compact circulator ring. In this paper, we present a proposal of a test facility utilizing the JLab FEL ERL for a technology demonstration of this cooler design concept. Beam studies will be performed and supporting technologies will also be developed in this test facility

TUO1C01

Recent Developments on High Intensity Beam Diagnostics at SNS

proton, cathode, target, simulation

292

W. Blokland
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 Ring accumulates 0.6 μs long proton bunches of up to 1.6·10¹⁴ protons with a typical peak current of over 50 A during a 1 ms cycle. To qualify the beam, we perform different transverse profile measurements that can be done at full intensity. The electron beam scanner performs a non-invasive measurement of the transverse and longitudinal profiles of the beam in the ring. Electrons passing over and through the proton beam are deflected and projected on a fluorescent screen. Analysis of the projection yields the transverse profile while multi transverse profiles offset in time yield the longitudinal profile. Progress made with this system will be discussed as well as temperature measurements of the stripping foil and other transverse measurements.

Slides TUO1C01 [15.498 MB]

WEO3A01

High Energy Electron Cooling

high-voltage, vacuum, gun, controls

363

V.B. Reva, M.I. Bryzgunov, V.M. Panasyuk, V.V. Parkhomchuk
BINP SB RAS, Novosibirsk, Russia

The electron cooler of a 2 MeV for COSY storage ring FZJ is assembled in BINP. This paper describes the first experimental results from the electron cooler with electron beam and high voltage. The cooling section is designed on the classic scheme of low energy coolers like cooler CSRm, CSRe, LEIR that was produced in BINP before. The electron beam is transported inside the longitudinal magnetic field along whole trajectory from an electron gun to a collector. This optic scheme is stimulated by the wide range of the working energies 0.1(0.025)-2 MeV. The electrostatic accelerator consists of 34 individual unify section. Each section contains two HV power supply (±30 kV) and power supply of the magnetic coils. The electrical power to each section is provided by the cascade transformer. The cascade transformer is the set of the transformer connected in series with isolating winding.

Slides WEO3A01 [7.902 MB]

WEO1B01

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

optics, emittance, injection, extraction

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.

WEO1C05

Longitudinal Space Charge Phenomena in an Intense Beam in a Ring

space-charge, induction, focusing, injection

447

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

Funding: Supported by the US Dept. of Energy, Offices of High Energy Physics and Fusion Energy Sciences, and by the US Dept. of Defense, Office of Naval Research and the Joint Technology Office.
The University of Maryland Electron Ring (UMER) uses nonrelativistic, high-current electron beams to access the intense space charge dynamics applicable to hadron beams. The UMER beam parameters correspond to space charge incoherent tune shifts, at injection, in the range of 1-5.5 integers. Longitudinal induction focusing is used to counteract the space charge force at the edges of a long rectangular bunch, confining the beam for 100s of turns. We report on two recent findings: (1) The formation and propagation of solitons from large amplitude longitudinal perturbations, observed experimentally and reproduced in WARP* simulations. (2) The evolution of a longitudinal multi-streaming instability when the space-charge force is allowed to lengthen the bunch ends. The expanding bunch ends fill the ring, interpenetrate, and wrap repeatedly, forming multiple streams at any one location, each with its unique velocity. The resulting multi-stream instability is investigated over a wide range of beam currents and initial pulse lengths, and experimental observations are in good agreement with WARP simulations and an analytical theory that successfully predicts the onset of the instability.
* D.P. Grote, A. Friedman, I. Haber, S. Yu, Fus. Eng. & Des. 32-33, 193-200 (1996).

Slides WEO1C05 [5.868 MB]

WEO3C01

Injection and Stripping Foil Studies for a 180 MeV Injection Upgrade at ISIS

injection, simulation, synchrotron, dipole

456

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

The Rutherford Appleton Laboratory (RAL) is home to ISIS, the world's most productive spallation neutron source. ISIS has two neutron producing target stations (TS-1 and TS-2), operated at 40 Hz and 10 Hz respectively with a 50 Hz, 800 MeV proton beam from a rapid cycling synchrotron (RCS), which is fed by a 70 MeV H− drift tube linac. The multi-turn charge-exchange injection process used on ISIS has been the subject of a programme of detailed studies in recent years including benchmarked simulations and experiments. More recently, these studies have been expanded as plans for upgrading ISIS have focussed on replacement of the 70 MeV linac with a new, higher energy injector and a new synchrotron injection straight. Whilst much of these studies have been reported elsewhere, this paper presents a summary of the programme with some further details.

Slides WEO3C01 [4.895 MB]

WEO3C03

Beam Halo Dynamics and Control with Hollow Electron Beams

collimation, collider, emittance, controls

466

G. Stancari, G. Annala, A. Didenko, T.R. Johnson, I.A. Morozov, V. Previtali, G.W. Saewert, V.D. Shiltsev, D.A. Still, A. Valishev, L.G. Vorobiev
Fermilab, Batavia, USA
R.W. Aßmann, R. Bruce, S. Redaelli, A. Rossi, B. Salvachua, G. Valentino
CERN, Geneva, Switzerland
D.N. Shatilov
BINP SB RAS, Novosibirsk, Russia

Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract DE-AC02-07CH11359 with the US Department of Energy. Partial support was provided by the US LHC Accelerator Research Program (LARP).
Experimental measurements of beam halo diffusion dynamics with collimator scans are reviewed. The concept of halo control with a hollow electron beam collimator, its demonstration at the Tevatron, and its possible applications at the LHC are discussed.

Slides WEO3C03 [5.139 MB]

THO1A01

Beam-beam Effects in RHIC

proton, resonance, simulation, emittance

479

Y. Luo, M. Bai, W. Fischer, C. Montag, S.M. White
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In this article we will review the beam-beam effects in the Relativistic Heavy Ion Collider (RHIC). We will cover the experimental observations, beam-beam simulation techniques and results, and head-on beam-beam compensation with electron lenses. The next luminosity goal in the RHIC polarized proton operation is to double the luminosity with a higher proton bunch intensity. After the upgrade, the beam-beam parameter will reach 0.03. Head-on beam-beam compensation is aimed to reduce the beam-beam tune spread and non-linear beam-beam resonance driving terms.

Slides THO1A01 [1.355 MB]

THO1B04

Space Charge Effects in the NICA Collider Rings

ion, collider, luminosity, emittance

522

O.S. Kozlov, S.A. Kostromin, I.N. Meshkov, A.O. Sidorin, A.V. Smirnov, G.V. Trubnikov
JINR, Dubna, Moscow Region, Russia
A.V. Eliseev
JINR/VBLHEP, Dubna, Moscow region, Russia
T. Katayama
GSI, Darmstadt, Germany

Accelerator complex NICA, developed at JINR, will provide an ion-ion (Au⁷⁹⁺) collisions at energies of 1-4.5 GeV/u, as well as experiments on collisions of polarized proton-proton and deuteron-deuteron beams. The calculations of the optical properties of superconducting collider rings have been aimed to create appropriate conditions for the collisions of beams and obtaining the required luminosity parameters in the working range of energies. The collider characteristics and the beam dynamics have been worked out mainly for ion-ion mode of the complex. The main effects limiting luminosity are the space charge dominating at the range of 1-3 GeV/u and the intrabeam scattering dominating for 3-4.5 GeV/u beams. Application of both electron and stochastic cooling methods is essential feature of the project. That allows us to suppress these effects in the corresponding energy ranges.

Slides THO1B04 [3.938 MB]

THO1B05

Broad-band Transverse Feedback against e-cloud or TMCI: Plan and Status

feedback, controls, kicker, pick-up

527

C.H. Rivetta, J.M. Cesaratto, J.D. Fox, M.T.F. Pivi, O. Turgut, S. Uemura
SLAC, Menlo Park, California, USA
W. Höfle, K.S.B. Li
CERN, Geneva, Switzerland

The feedback control of intra-bunch instabilities driven by electron-clouds or strong head-tail coupling (Transverse mode coupled instabilities, TMCI) requires bandwidth sufficient to sense the vertical position and apply multiple corrections within a nanosecond-scale bunch. These requirements impose challenges and limits in the design and implementation of the feedback system. To develop the feedback control prototype, different research areas have been pursed to model and identify the bunch dynamics, design the feedback control and implement the GigaHertz bandwidth hardware. This paper presents those R&D lines and reports on the progress as it stands today. It presents preliminary results of feedback systems stabilizing the transverse intra-bunch motion, based on macro-particle simulation codes (CMAD / HeadTail) and measurement results of the beam motion when it is driven by particular excitation signals.

Slides THO1B05 [7.197 MB]

THO3B05

Intense High Charge State Heavy Ion Beam Production for the Advanced Accelerators

ion, ion-source, ECRIS, plasma

550

L.T. Sun
IMP, Lanzhou, People's Republic of China

Modern advanced heavy ion beam accelerators have strong needs for either dc or pulsed intense high charge state heavy ion beams, such as dc beams for FRIB project, SPIRAL2 project, HIRFL/IMP facility, RIBF/RIKEN facility ect, and pulsed beams for RHIC, LHC, FAIR project. After decades' development, only several typical ion sources have found their applications in these accelerators, i.e. ECR ion source, EBIS and LIS or Laser Ion Source. This paper will give a general review of the advantages and limitations of the three types of ion sources. The latest development and performance for the three types of ion sources will be presented.

Slides THO3B05 [2.464 MB]

THO3C01

Optical Transition Radiation for Non-relativistic Ion Beams

ion, target, photon, radiation

580

B. Walasek-Höhne, C.A. Andre, F. Becker, P. Forck, A. Reiter, M. Schwickert, R. Singh
GSI, Darmstadt, Germany
A.H. Lumpkin
Fermilab, Batavia, USA

In this contribution, recent results of Optical Transition Radiation (OTR) measurements with a non-relativistic heavy-ion beam will be presented. This feasibility study was prompted by previous measurements [1] and the theoretical estimation of expected signal strengths for the GSI linear accelerator UNILAC. For this experiment, an 11.4 MeV/u Uranium beam was chosen to investigate OTR signal from several target materials and to evaluate the working regime for the used experimental setup. The OTR light was either observed directly with an Image Intensified CCD camera (ICCD) or indirectly via a spectrometer for wavelength resolved data. A moveable stripping foil allowed measurements with two different ion charge states. The theoretical q2 dependency of the OTR process predicts a six-fold increase in light yield which was confirmed experimentally. Obtained OTR beam profiles were compered to SEM-Grid data. Moreover, ICCD gating feature, as well as the emitted light spectrum ruled out contribution of any background sources with longer emission time constant e.g. blackbody radiation.
[1] C. Bal et al., "OTR from Non-relativistic Electrons", Proceedings of DIPAC03, PM04, Mainz Germany.

Slides THO3C01 [1.905 MB]

THO3C03

Beam Induced Fluorescence - Profile Monitoring for Targets and Transport

vacuum, ion, target, cathode

586

F. Becker, C.A. Andre, C. Dorn, P. Forck, R. Haseitl, B. Walasek-Höhne
GSI, Darmstadt, Germany
T. Dandl, T. Heindl, A. Ulrich
TUM/Physik, Garching bei München, Germany
J. Egberts, T. Papaevangelou
CEA, Gif-sur-Yvette, France
J. Marroncle
CEA/IRFU, Gif-sur-Yvette, France

Online profile diagnostic is preferred to monitor intense hadron beams at the Facility of Antiproton and Ion Research (FAIR). One instrument for beam profile measurement is the gas based Beam Induced Fluorescence (BIF)-monitor. It relies on the optical fluorescence of residual gas, excited by beam particles. In front of production targets for radioactive ion beams or in plasma physics applications, vacuum constraints are less restrictive and allow a sufficient number of fluorescence photons, even at minimum ionizing energies. Unwanted effects like radiation damage and radiation induced background need to be addressed as well. A profile comparison of BIF and Ionization Profile Monitor (IPM) in nitrogen and rare gases is presented. We studied the BIF method from 10^-3 to 30 mbar with an imaging spectrograph. Preferable fluorescence transitions and fundamental limitations are discussed.

Slides THO3C03 [7.371 MB]

THO3C05

Fiber Based BLM System Research and Development at CERN

photon, radiation, beam-losses, quadrupole

596

S. Mallows
The University of Liverpool, Liverpool, United Kingdom
E.B. Holzer, S. Mallows, J.W. van Hoorne
CERN, Geneva, Switzerland

The application of a beam loss measurement (BLM) system based on Cherenkov light generated in optical fibers to a linear accelerator with long bunch trains is currently under investigation at CERN. In the context of the Compact Linear Collider (CLIC) study, the machine protection role of the BLM system consists of its input to the \lqnext cycle permit\rq. In between two cycles it is determined whether it is safe to commit the machine for the next cycle. A model for light production and propagation has been developed and validated with beam measurements. Monte Carlo simulations of loss scenarios established the suitability in terms of sensitivity and dynamic range. The achievable longitudinal position resolution of the system, considering that the bunch trains and the optical fiber length are comparable in size is discussed.

Slides THO3C05 [3.846 MB]