IPAC2012 - List of Authors (Zhang, C.)

Paper	Title	Page
THPPC034	Design and Analysis of the PXIE CW Radio-frequency Quadrupole (RFQ)	3359
	S.P. Virostek, M.D. Hoff, A.R. Lambert, D. Li, J.W. Staples LBNL, Berkeley, California, USA G.V. Romanov Fermilab, Batavia, USA C. Zhang IAP, Frankfurt am Main, Germany
	Funding: This work is supported by the Office of Science, United States Department of Energy under DOE contract DE-AC02-05CH11231. The Project X Injector Experiment (PXIE) will be a prototype front end of the Project X accelerator proposed by Fermilab. PXIE will consist of an H⁻ ion source, a low-energy beam transport (LEBT), a radio-frequency quadrupole (RFQ) accelerator, a medium-energy beam transport (MEBT) and a section of superconducting cryomodules that will accelerate the beam from 30 keV to 30 MeV. LBNL has developed an RFQ design for PXIE with fabrication scheduled to begin before the end of CY 2012. The chosen baseline design is a four-vane, 4.4 m long CW RFQ with a resonant frequency at 162.5 MHz (2.4 wavelengths long). The RFQ will provide bunching and acceleration of a nominal 5 mA H⁻ beam to 2.1 MeV. The relatively low wall power density results in wall power losses that are less than 100 kW. The beam dynamics design has been optimized to allow for more than 99% beam capture with exceptionally low longitudinal emittance. The RFQ mechanical design and the results of RF and thermal analyses are presented here.

THPPP092	Progress of the Front-End System Development for Project X at LBNL	3951
	D. Li, M.D. Hoff, Q. Ji, A.R. Lambert, T. Schenkel, J.W. Staples, S.P. Virostek LBNL, Berkeley, California, USA S. Nagaitsev, L.R. Prost, G.V. Romanov, A.V. Shemyakin Fermilab, Batavia, USA C. Zhang IAP, Frankfurt am Main, Germany
	Funding: This work is supported by the Office of Science, United States Department of Energy under DOE contract DE-AC02-05CH11231. A multi-MW proton facility, Project X has been proposed and is currently under development at Fermilab. Project X is a key accelerator complex for intensity frontier of future high energy physics programs in the US. In collaboration with Fermilab, LBNL takes the responsibility in the development and design studies of the front-end system for Project X. The front-end system would consist of H⁻ ion source(s), low-energy beam transport (LEBT), 162.5 MHz normal conducting CW Radio-Frequency-Quadrupole (RFQ) accelerator, medium-energy beam transport (MEBT), and beam chopper(s). In this paper, we will review and present recent progress of the front-end system studies, which will include the RFQ beam dynamics design, RF structure design, thermal and mechanical analyses and fabrication plan, LEBT simulation studies and concept for LEBT chopper.

MOPPR034	A Laser Wire System at Electron Beam Transport Line in BEPCII	852
	C. Zhang, J. Cao, Q.Y. Deng, Y.F. Sui IHEP, Beijing, People's Republic of China
	Funding: National Natural Science Foundation of China A Laser Wire system is under development at transport line in BEPCII (Beijing Electron Positron Collider). The structure of whole system is briefly described in this paper. Some work on laser and detector are presented. We also discussed the challenge of Laser Wire and some other things that can affect measurement. According to the plan, the Laser Wire will be installed in electron beam transport line in the summer of 2012.

TUPPC016	Progress of Emittance Coupling Correction at the SPring-8 Storage Ring	1191
	M. Takao, M. Masaki, Y. Shimosaki, K. Soutome, S. Takano, C. Zhang JASRI/SPring-8, Hyogo-ken, Japan
	The vertical beam spread, or the emittance coupling, is one of the most important parameters for the high brilliance light source storage ring. By the precise alignment of the magnets and the proper COD correction, at the commissioning phase of the SPring-8 storage ring we succeeded in achieving the very small coupling ~0.2 % without correction. However, the coupling had grown large with the years, so recently we have corrected it and recovered the initial performance. The scheme of the coupling correction at the SPring-8 storage ring is the global one, which is based on the perturbation theory with single resonance approximation. In the beginning of the correction the coupling was corrected by means of minimizing the vertical beam size. Then the performance of the coupling correction has been further improved by changing the scheme to minimizing the betatron coupling mode in the vertical oscillation of the horizontally kicked beam. This result implies that the higher order coupling contributes to the emittance coupling, which can be corrected by the higher skew multi-pole magnet. The present status of the coupling correction at the SPring-8 storage ring will be reported.

TUPPC015	Local Modification of Lattice of a Long Straight Section for Installing Small Gap In-vacuum Undulators at SPring-8	1188
	K. Soutome, T. Fujita, K. Fukami, K.K. Kaneki, C. Mitsuda, H. Ohkuma, M. Oishi, Y. Okayasu, S. Sasaki, J. Schimizu, Y. Shimosaki, M. Shoji, M. Takao, Y. Taniuchi, C. Zhang JASRI/SPring-8, Hyogo-ken, Japan M. Hasegawa, K. Kajimoto, T. Nakanishi SES, Hyogo-pref., Japan
	In the SPring-8 storage ring there are four magnet-free long straight sections (LSS) of about 30m. Recently we locally modified one of these sections by installing two quadrupole-triplets and divided it into three sub-sections. The vertical beta at the middle of each sub-section was lowered to 2.5m so that small gap in-vacuum undulators with a short period (min. gap: 5.2mm, period: 19mm) can be installed to build a high performance beamline for inelastic X-ray scattering. After modifying the lattice, however, the symmetry of the ring is lowered and, in general, it becomes difficult to keep sufficient dynamic aperture (DA) and momentum acceptance (MA). We solved this problem by combining the betatron phase matching, local chromaticity correction in LSS and cancellation of non-linear kicks due to sextupoles used for this correction. We could then recover DA and MA to almost the same level for the original one. The beam commissioning of the new lattice has successfully been finished, and from September 2011 it is used in user-operation. We will report our method of realizing a storage ring lattice having a very low symmetry and review the operation performance of the modified lattice.

Paper

Title

Page

Design and Analysis of the PXIE CW Radio-frequency Quadrupole (RFQ)

3359

S.P. Virostek, M.D. Hoff, A.R. Lambert, D. Li, J.W. Staples
LBNL, Berkeley, California, USA
G.V. Romanov
Fermilab, Batavia, USA
C. Zhang
IAP, Frankfurt am Main, Germany

Funding: This work is supported by the Office of Science, United States Department of Energy under DOE contract DE-AC02-05CH11231.
The Project X Injector Experiment (PXIE) will be a prototype front end of the Project X accelerator proposed by Fermilab. PXIE will consist of an H⁻ ion source, a low-energy beam transport (LEBT), a radio-frequency quadrupole (RFQ) accelerator, a medium-energy beam transport (MEBT) and a section of superconducting cryomodules that will accelerate the beam from 30 keV to 30 MeV. LBNL has developed an RFQ design for PXIE with fabrication scheduled to begin before the end of CY 2012. The chosen baseline design is a four-vane, 4.4 m long CW RFQ with a resonant frequency at 162.5 MHz (2.4 wavelengths long). The RFQ will provide bunching and acceleration of a nominal 5 mA H⁻ beam to 2.1 MeV. The relatively low wall power density results in wall power losses that are less than 100 kW. The beam dynamics design has been optimized to allow for more than 99% beam capture with exceptionally low longitudinal emittance. The RFQ mechanical design and the results of RF and thermal analyses are presented here.

THPPP092

Progress of the Front-End System Development for Project X at LBNL

3951

D. Li, M.D. Hoff, Q. Ji, A.R. Lambert, T. Schenkel, J.W. Staples, S.P. Virostek
LBNL, Berkeley, California, USA
S. Nagaitsev, L.R. Prost, G.V. Romanov, A.V. Shemyakin
Fermilab, Batavia, USA
C. Zhang
IAP, Frankfurt am Main, Germany

Funding: This work is supported by the Office of Science, United States Department of Energy under DOE contract DE-AC02-05CH11231.
A multi-MW proton facility, Project X has been proposed and is currently under development at Fermilab. Project X is a key accelerator complex for intensity frontier of future high energy physics programs in the US. In collaboration with Fermilab, LBNL takes the responsibility in the development and design studies of the front-end system for Project X. The front-end system would consist of H⁻ ion source(s), low-energy beam transport (LEBT), 162.5 MHz normal conducting CW Radio-Frequency-Quadrupole (RFQ) accelerator, medium-energy beam transport (MEBT), and beam chopper(s). In this paper, we will review and present recent progress of the front-end system studies, which will include the RFQ beam dynamics design, RF structure design, thermal and mechanical analyses and fabrication plan, LEBT simulation studies and concept for LEBT chopper.

MOPPR034

A Laser Wire System at Electron Beam Transport Line in BEPCII

852

C. Zhang, J. Cao, Q.Y. Deng, Y.F. Sui
IHEP, Beijing, People's Republic of China

Funding: National Natural Science Foundation of China
A Laser Wire system is under development at transport line in BEPCII (Beijing Electron Positron Collider). The structure of whole system is briefly described in this paper. Some work on laser and detector are presented. We also discussed the challenge of Laser Wire and some other things that can affect measurement. According to the plan, the Laser Wire will be installed in electron beam transport line in the summer of 2012.

TUPPC016

Progress of Emittance Coupling Correction at the SPring-8 Storage Ring

1191

M. Takao, M. Masaki, Y. Shimosaki, K. Soutome, S. Takano, C. Zhang
JASRI/SPring-8, Hyogo-ken, Japan

The vertical beam spread, or the emittance coupling, is one of the most important parameters for the high brilliance light source storage ring. By the precise alignment of the magnets and the proper COD correction, at the commissioning phase of the SPring-8 storage ring we succeeded in achieving the very small coupling ~0.2 % without correction. However, the coupling had grown large with the years, so recently we have corrected it and recovered the initial performance. The scheme of the coupling correction at the SPring-8 storage ring is the global one, which is based on the perturbation theory with single resonance approximation. In the beginning of the correction the coupling was corrected by means of minimizing the vertical beam size. Then the performance of the coupling correction has been further improved by changing the scheme to minimizing the betatron coupling mode in the vertical oscillation of the horizontally kicked beam. This result implies that the higher order coupling contributes to the emittance coupling, which can be corrected by the higher skew multi-pole magnet. The present status of the coupling correction at the SPring-8 storage ring will be reported.

TUPPC015

Local Modification of Lattice of a Long Straight Section for Installing Small Gap In-vacuum Undulators at SPring-8

1188

K. Soutome, T. Fujita, K. Fukami, K.K. Kaneki, C. Mitsuda, H. Ohkuma, M. Oishi, Y. Okayasu, S. Sasaki, J. Schimizu, Y. Shimosaki, M. Shoji, M. Takao, Y. Taniuchi, C. Zhang
JASRI/SPring-8, Hyogo-ken, Japan
M. Hasegawa, K. Kajimoto, T. Nakanishi
SES, Hyogo-pref., Japan

In the SPring-8 storage ring there are four magnet-free long straight sections (LSS) of about 30m. Recently we locally modified one of these sections by installing two quadrupole-triplets and divided it into three sub-sections. The vertical beta at the middle of each sub-section was lowered to 2.5m so that small gap in-vacuum undulators with a short period (min. gap: 5.2mm, period: 19mm) can be installed to build a high performance beamline for inelastic X-ray scattering. After modifying the lattice, however, the symmetry of the ring is lowered and, in general, it becomes difficult to keep sufficient dynamic aperture (DA) and momentum acceptance (MA). We solved this problem by combining the betatron phase matching, local chromaticity correction in LSS and cancellation of non-linear kicks due to sextupoles used for this correction. We could then recover DA and MA to almost the same level for the original one. The beam commissioning of the new lattice has successfully been finished, and from September 2011 it is used in user-operation. We will report our method of realizing a storage ring lattice having a very low symmetry and review the operation performance of the modified lattice.