IPAC2012 - List of Authors (Wang, S.)

Paper	Title	Page
MOPPR079	Horizontal Beam-size Measurements at CESR-TA Using Synchrotron-light Interferometer	972
	S. Wang, J.V. Conway, D.L. Hartill, M.A. Palmer, D. L. Rubin CLASSE, Ithaca, New York, USA R.F. Campbell, R. Holtzapple CalPoly, San Luis Obispo, California, USA
	Funding: DOE Award DE-FC02-08ER41538 NSF Award (PHY-0734867) NSF Award (PHY-1002467) NSF Award (PHY-1068662). A horizontal beam profile monitor utilizing visible synchrotron radiation from a bending magnet has been designed and installed in CESR. The monitor employs a double-slit interferometer which has been successfully implemented to measure horizontal beam sizes over a wide range of beam currents. By varying the separation of the slits, beam sizes ranging from 50 to 500 microns can be measured with a resolution of approximately 5 microns. The method for extracting the horizontal beam size from the interference pattern is presented and its application to intrabeam scattering studies is described. A configuration for measuring the small vertical beam size is also discussed.

WEPPR015	Intrabeam Scattering Studies at CesrTA	2970
	M. P. Ehrlichman Cornell University, Ithaca, New York, USA F. Antoniou, Y. Papaphilippou CERN, Geneva, Switzerland W. Hartung, M.A. Palmer, D.P. Peterson, N.T. Rider, D. L. Rubin, J.P. Shanks, C.R. Strohman, S. Wang CLASSE, Ithaca, New York, USA R. Holtzapple CalPoly, San Luis Obispo, California, USA
	Funding: NSF Award (PHY-0734867) NSF Award (PHY-1002467) Japan/US Cooperation Program Education and lifelong learning, co-financed by Greece and the European Union Intrabeam scattering dilutes the emittance of low energy, low emittance rings. Because CesrTA can be operated at low energies with low transverse emittances and high bunch intensity, it is an ideal laboratory for the study of IBS effects. Furthermore, CesrTA is instrumented for accurate beam size measurements in all three dimensions, providing the possibility of a complete determination of the intensity dependence of emittances. Models based on classical IBS theories and multi-particle simulations are used to estimate the effect of IBS at CesrTA at different beam emittances, intensities and energies. The first measurements from machine studies at CesrTA are presented.

MOPPD075	Optimization of the Collimation System for the CSNS/RCS	538
	N. Wang, M.Y. Huang, S. Wang, S.Y. Xu IHEP, Beijing, People's Republic of China
	Beam loss induced activation of the accelerator components is one of the primary concerns in designing a high intensity machine. The uncontrolled beam loss is required to be less than 1 W/m for hands-on maintenance of the machine. A two stage collimation system is designed in the Rapid Cycling Synchrotron (RCS) of the China Spallation Neutron Source (CSNS) to localize the beam losses in a restricted area. The parameters of the collimator are optimized in order to obtain high collimation efficiency. The final design of the collimation system is presented. The reliability of the collimation system is estimated for different working points and with closed orbit errors.

TUEPPB004	A Longitudinal Beam Dynamics Code for Proton Synchrotron	1119
	Y.S. Yuan, N. Wang, S. Wang, S.Y. Xu IHEP, Beijing, People's Republic of China
	The accelerator of China Spallation Neutron Source (CSNS) consists of an 80 MeV linac and a 1.6 GeV Rapid Cycling Synchrotron (RCS). Longitudinal beam dynamics study is one of the most important issues for RCS beam dynamics design. However, the existing codes cannot meet the requirement of longitudinal beam dynamics for CSNS/RCS. A new code has been developed for longitudinal beam dynamics design and simulation. The code can perform the voltage and phase curves design for non-sinusoidal magnetic field of dipole in an RCS cycle, with the fundamental RF mode and dual harmonic mode. The code can also be used for the beam simulation with longitudinal space charge effect, including the effects of higher order mode of RF cavities. By using the code, the longitudinal beam dynamics of CSNS/RCS was designed and optimized, and the simulation study with dual harmonics higher order modes of RF cavity was done, and the simulation results are presented.

THEPPB005	Study on the Injection Optimization and Transverse Coupling for CSNS/RCS	3240
	M.Y. Huang, J. Qiu, S. Wang, S.Y. Xu IHEP, Beijing, People's Republic of China
	The injection system of the China Spallation Neutron Source uses H⁻ stripping and phase space painting method to fill large ring acceptance with the linac beam of small emittance. The emittance evolution, beam losses, and collimation efficiency during the injection procedures for different injection parameters, such as the injection emittances, starting injection time, twiss parameters and momentum spread, were studied, and then the optimized injection parameters was obtained. In addition, the phase space painting scheme which also affect the emittance evolution and beam losses were simulated and the optimization range of phase space painting were obtained. There will be wobble in the power supply of the injection bumps, and the wobble effects were presented. In order to study the transverse coupling, the injection procedures for different betatron tunes and momentum spreads were studied.

THPPC012	Impedance Computation of Main Components in CSNS/RCS	3299
	Y. Li, L. Huang, Z.P. Li, Y.D. Liu, N. Wang, S. Wang IHEP, Beijing, People's Republic of China
	The rapid cycling synchrotron (RCS) of the China spallation neutron source (CSNS) is a high intensity proton accelerator. The study on the coupling impedance in the ring plays an important role in the stability of the beam. The impedance of the main vacuum components in the RCS ring, such as RF cavities, bellows, ports of vacuum pumps, collimator etc, was calculated by using numerical methods. Meantime, RF shielding of bellows, collimators and ports of vacuum pumps are considered. The impact of the busbar configuration on RF cavities and beams was estimated by impedance calculation.

Paper

Title

Page

Horizontal Beam-size Measurements at CESR-TA Using Synchrotron-light Interferometer

972

S. Wang, J.V. Conway, D.L. Hartill, M.A. Palmer, D. L. Rubin
CLASSE, Ithaca, New York, USA
R.F. Campbell, R. Holtzapple
CalPoly, San Luis Obispo, California, USA

Funding: DOE Award DE-FC02-08ER41538 NSF Award (PHY-0734867) NSF Award (PHY-1002467) NSF Award (PHY-1068662).
A horizontal beam profile monitor utilizing visible synchrotron radiation from a bending magnet has been designed and installed in CESR. The monitor employs a double-slit interferometer which has been successfully implemented to measure horizontal beam sizes over a wide range of beam currents. By varying the separation of the slits, beam sizes ranging from 50 to 500 microns can be measured with a resolution of approximately 5 microns. The method for extracting the horizontal beam size from the interference pattern is presented and its application to intrabeam scattering studies is described. A configuration for measuring the small vertical beam size is also discussed.

WEPPR015

Intrabeam Scattering Studies at CesrTA

2970

M. P. Ehrlichman
Cornell University, Ithaca, New York, USA
F. Antoniou, Y. Papaphilippou
CERN, Geneva, Switzerland
W. Hartung, M.A. Palmer, D.P. Peterson, N.T. Rider, D. L. Rubin, J.P. Shanks, C.R. Strohman, S. Wang
CLASSE, Ithaca, New York, USA
R. Holtzapple
CalPoly, San Luis Obispo, California, USA

Funding: NSF Award (PHY-0734867) NSF Award (PHY-1002467) Japan/US Cooperation Program Education and lifelong learning, co-financed by Greece and the European Union
Intrabeam scattering dilutes the emittance of low energy, low emittance rings. Because CesrTA can be operated at low energies with low transverse emittances and high bunch intensity, it is an ideal laboratory for the study of IBS effects. Furthermore, CesrTA is instrumented for accurate beam size measurements in all three dimensions, providing the possibility of a complete determination of the intensity dependence of emittances. Models based on classical IBS theories and multi-particle simulations are used to estimate the effect of IBS at CesrTA at different beam emittances, intensities and energies. The first measurements from machine studies at CesrTA are presented.

MOPPD075

Optimization of the Collimation System for the CSNS/RCS

538

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

Beam loss induced activation of the accelerator components is one of the primary concerns in designing a high intensity machine. The uncontrolled beam loss is required to be less than 1 W/m for hands-on maintenance of the machine. A two stage collimation system is designed in the Rapid Cycling Synchrotron (RCS) of the China Spallation Neutron Source (CSNS) to localize the beam losses in a restricted area. The parameters of the collimator are optimized in order to obtain high collimation efficiency. The final design of the collimation system is presented. The reliability of the collimation system is estimated for different working points and with closed orbit errors.

TUEPPB004

A Longitudinal Beam Dynamics Code for Proton Synchrotron

1119

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

The accelerator of China Spallation Neutron Source (CSNS) consists of an 80 MeV linac and a 1.6 GeV Rapid Cycling Synchrotron (RCS). Longitudinal beam dynamics study is one of the most important issues for RCS beam dynamics design. However, the existing codes cannot meet the requirement of longitudinal beam dynamics for CSNS/RCS. A new code has been developed for longitudinal beam dynamics design and simulation. The code can perform the voltage and phase curves design for non-sinusoidal magnetic field of dipole in an RCS cycle, with the fundamental RF mode and dual harmonic mode. The code can also be used for the beam simulation with longitudinal space charge effect, including the effects of higher order mode of RF cavities. By using the code, the longitudinal beam dynamics of CSNS/RCS was designed and optimized, and the simulation study with dual harmonics higher order modes of RF cavity was done, and the simulation results are presented.

THEPPB005

Study on the Injection Optimization and Transverse Coupling for CSNS/RCS

3240

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

The injection system of the China Spallation Neutron Source uses H⁻ stripping and phase space painting method to fill large ring acceptance with the linac beam of small emittance. The emittance evolution, beam losses, and collimation efficiency during the injection procedures for different injection parameters, such as the injection emittances, starting injection time, twiss parameters and momentum spread, were studied, and then the optimized injection parameters was obtained. In addition, the phase space painting scheme which also affect the emittance evolution and beam losses were simulated and the optimization range of phase space painting were obtained. There will be wobble in the power supply of the injection bumps, and the wobble effects were presented. In order to study the transverse coupling, the injection procedures for different betatron tunes and momentum spreads were studied.

THPPC012

Impedance Computation of Main Components in CSNS/RCS

3299

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

The rapid cycling synchrotron (RCS) of the China spallation neutron source (CSNS) is a high intensity proton accelerator. The study on the coupling impedance in the ring plays an important role in the stability of the beam. The impedance of the main vacuum components in the RCS ring, such as RF cavities, bellows, ports of vacuum pumps, collimator etc, was calculated by using numerical methods. Meantime, RF shielding of bellows, collimators and ports of vacuum pumps are considered. The impact of the busbar configuration on RF cavities and beams was estimated by impedance calculation.