HB2012 - List of Keywords (scattering)

Paper	Title	Other Keywords	Page
MOP207	Planning for Experimental Demonstration of Transverse Emittance Transfer at the GSI UNILAC through Eigen-emittance Shaping	emittance, quadrupole, coupling, simulation	57
	C. Xiao, O.K. Kester IAP, Frankfurt am Main, Germany L. Groening GSI, Darmstadt, Germany
	The minimum transverse emittances achievable in a beam line are determined by the two transverse eigen-emittances of the beam. For vanishing interplane correlations they are equal to the well-know rms-emittances. Eigen-emittances are constants of motion for all symplectic beam line elements, i.e. (even tilted) linear elements. To allow for rms-emittance transfer, the eigen-emittances must be changed by applying a non-symplectic action to the beam, preferably preserving the 4d-rms-emittance. This contribution will introduce the concept for eigen-emittance shaping and rms-emittance transfer at an ion linac. A path towards the experimental demonstration of the concept at the GSI UNILAC is presented.

MOP213	Beam Losses due to the Foil Scattering for CSNS/RCS	beam-losses, injection, proton, electron	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.

MOP253	Progress with Bunch-shape Measurements at PSI's High-power Cyclotrons and Proton Beam Lines	proton, cyclotron, simulation, background	187
	R. Dölling PSI, Villigen PSI, Switzerland
	As proposed at HB2010, additional bunch-shape monitors have been installed at the last turns of the Injector 2 cyclotron and at several locations in the connecting beam line to the Ring cyclotron (@72 MeV), as well as behind the Ring cyclotron (@590 MeV). Now at each location in the beam lines, longitudinal-transversal 2D-density distributions of the bunched 2.2 mA proton beam can be taken from four angles of view, each separated by 45°. In addition the monitor in Injector 2 has been upgraded to observe the 13 outermost turns (@57 to 72 MeV), some of them from two or three angles of view. The measurement setup, data evaluation and results are outlined.

MOP256	High-power Scaling FFAG Ring Studies	injection, space-charge, lattice, dynamic-aperture	202
	D.J. Kelliher, S. Machida, G.H. Rees STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
	High-power scaling FFAG rings have potential application in areas such as neutron spallation, muon production, and accelerator-driven systems. It is proposed to build a model of such a ring in order to study major issues such as space charge and injection. A 20 ' 70 MeV radial DFD FFAG model, that was initially described in , incorporates long straights to facilitate H⁻ charge exchange injection. Bump magnets are used to move the injected beam away from the foil. The effect of the injection process on the beam emittance is considered. The tune depression and emittance blow up resulting from the effect of space charge is also calculated. G.H. Rees et al, ‘A Model for a High-Power Scaling FFAG Ring', IPAC12, New Orleans, 2012, MOPPD020, http://www. JACow.org

TUO1B01	Beam Loss Due to Foil Scattering in the SNS Accumulator Ring	injection, proton, collimation, extraction	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, extraction	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]

WEO1B02	Optics Design Optimization for IBS Dominated Beams	emittance, optics, ion, damping	386
	F. Antoniou, H. Bartosik, Y. Papaphilippou CERN, Geneva, Switzerland T. Demma LAL, Orsay, France N. Milas, A. Streun PSI, Villigen PSI, Switzerland M.T.F. Pivi SLAC, Menlo Park, California, USA
	Intra-beam scattering is a small angle multiple Coulomb scattering effect, leading to emittance growth. It becomes important for high brightness beams in low emittance lepton rings, but also hadron synchrotrons and ring colliders. Several theoretical models have been developed over the years, however, when the IBS becomes predominant, the divergence between the models becomes important. In addition, the theoretical models are based on the consideration of Gaussian beams and uncoupled transverse motion. Recently, two multi-particle tracking codes have been developed, in order to enable the understanding of the IBS influence on the beam distribution and the inclusion of coupling. The comparison between theoretical models in different lattices and different regimes is discussed here and the benchmarking of the theoretical models with the tracking codes is presented. Finally, first measurement results are presented in low emittance rings and hadron synchrotrons.
	Slides WEO1B02 [2.389 MB]

WEO3C02	Collimation of Ion Beams	ion, collimation, proton, heavy-ion	461
	I. Strašík, O. Boine-Frankenheim GSI, Darmstadt, Germany
	The SIS 100 synchrotron as part of the FAIR project at GSI will accelerate various beam species from proton to uranium. An important issue is to minimize uncontrolled beam losses using a collimation system. An application of the two-stage collimation concept, well established for proton accelerators, is considered for the fully-stripped ion beams. The two-stage system consists of a primary collimator (a scattering foil) and secondary collimators (bulky absorbers). The main tasks of this study are: to specify beam optics of the system, to calculate dependence of the scattering angle in the foil on the projectile species, to investigate importance of the inelastic nuclear interaction in the foil and to calculate dependence of the collimation efficiency on the projectile species. A concept for the collimation of partially-stripped ions is based on the stripping of remaining electrons and deflecting using a beam optical element towards a dump location. Residual activation and radiation damage issues of collimator materials are also being studied at GSI. Experimental results from irradiation of carbon-based materials by heavy ions are presented.
	Slides WEO3C02 [1.485 MB]

Paper

Title

Other Keywords

Page

Planning for Experimental Demonstration of Transverse Emittance Transfer at the GSI UNILAC through Eigen-emittance Shaping

emittance, quadrupole, coupling, simulation

57

C. Xiao, O.K. Kester
IAP, Frankfurt am Main, Germany
L. Groening
GSI, Darmstadt, Germany

The minimum transverse emittances achievable in a beam line are determined by the two transverse eigen-emittances of the beam. For vanishing interplane correlations they are equal to the well-know rms-emittances. Eigen-emittances are constants of motion for all symplectic beam line elements, i.e. (even tilted) linear elements. To allow for rms-emittance transfer, the eigen-emittances must be changed by applying a non-symplectic action to the beam, preferably preserving the 4d-rms-emittance. This contribution will introduce the concept for eigen-emittance shaping and rms-emittance transfer at an ion linac. A path towards the experimental demonstration of the concept at the GSI UNILAC is presented.

MOP213

Beam Losses due to the Foil Scattering for CSNS/RCS

beam-losses, injection, proton, electron

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.

MOP253

Progress with Bunch-shape Measurements at PSI's High-power Cyclotrons and Proton Beam Lines

proton, cyclotron, simulation, background

187

R. Dölling
PSI, Villigen PSI, Switzerland

As proposed at HB2010, additional bunch-shape monitors have been installed at the last turns of the Injector 2 cyclotron and at several locations in the connecting beam line to the Ring cyclotron (@72 MeV), as well as behind the Ring cyclotron (@590 MeV). Now at each location in the beam lines, longitudinal-transversal 2D-density distributions of the bunched 2.2 mA proton beam can be taken from four angles of view, each separated by 45°. In addition the monitor in Injector 2 has been upgraded to observe the 13 outermost turns (@57 to 72 MeV), some of them from two or three angles of view. The measurement setup, data evaluation and results are outlined.

MOP256

High-power Scaling FFAG Ring Studies

injection, space-charge, lattice, dynamic-aperture

202

D.J. Kelliher, S. Machida, G.H. Rees
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

High-power scaling FFAG rings have potential application in areas such as neutron spallation, muon production, and accelerator-driven systems. It is proposed to build a model of such a ring in order to study major issues such as space charge and injection. A 20 ' 70 MeV radial DFD FFAG model, that was initially described in *, incorporates long straights to facilitate H⁻ charge exchange injection. Bump magnets are used to move the injected beam away from the foil. The effect of the injection process on the beam emittance is considered. The tune depression and emittance blow up resulting from the effect of space charge is also calculated.
* G.H. Rees et al, ‘A Model for a High-Power Scaling FFAG Ring', IPAC12, New Orleans, 2012, MOPPD020, http://www. JACow.org

TUO1B01

Beam Loss Due to Foil Scattering in the SNS Accumulator Ring

injection, proton, collimation, extraction

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, extraction

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]

WEO1B02

Optics Design Optimization for IBS Dominated Beams

emittance, optics, ion, damping

386

F. Antoniou, H. Bartosik, Y. Papaphilippou
CERN, Geneva, Switzerland
T. Demma
LAL, Orsay, France
N. Milas, A. Streun
PSI, Villigen PSI, Switzerland
M.T.F. Pivi
SLAC, Menlo Park, California, USA

Intra-beam scattering is a small angle multiple Coulomb scattering effect, leading to emittance growth. It becomes important for high brightness beams in low emittance lepton rings, but also hadron synchrotrons and ring colliders. Several theoretical models have been developed over the years, however, when the IBS becomes predominant, the divergence between the models becomes important. In addition, the theoretical models are based on the consideration of Gaussian beams and uncoupled transverse motion. Recently, two multi-particle tracking codes have been developed, in order to enable the understanding of the IBS influence on the beam distribution and the inclusion of coupling. The comparison between theoretical models in different lattices and different regimes is discussed here and the benchmarking of the theoretical models with the tracking codes is presented. Finally, first measurement results are presented in low emittance rings and hadron synchrotrons.

Slides WEO1B02 [2.389 MB]

WEO3C02

Collimation of Ion Beams

ion, collimation, proton, heavy-ion

461

I. Strašík, O. Boine-Frankenheim
GSI, Darmstadt, Germany

The SIS 100 synchrotron as part of the FAIR project at GSI will accelerate various beam species from proton to uranium. An important issue is to minimize uncontrolled beam losses using a collimation system. An application of the two-stage collimation concept, well established for proton accelerators, is considered for the fully-stripped ion beams. The two-stage system consists of a primary collimator (a scattering foil) and secondary collimators (bulky absorbers). The main tasks of this study are:

to specify beam optics of the system,
to calculate dependence of the scattering angle in the foil on the projectile species,
to investigate importance of the inelastic nuclear interaction in the foil and
to calculate dependence of the collimation efficiency on the projectile species.

A concept for the collimation of partially-stripped ions is based on the stripping of remaining electrons and deflecting using a beam optical element towards a dump location. Residual activation and radiation damage issues of collimator materials are also being studied at GSI. Experimental results from irradiation of carbon-based materials by heavy ions are presented.

Slides WEO3C02 [1.485 MB]