2011 Particle Accelerator Conference - List of Authors (Wu, W.)

Paper

Title

Page

Design of Longitudinal Feedback Kicker for HLS Storage Ring

612

W. Xu, D.H. He
USTC/NSRL, Hefei, Anhui, People's Republic of China
W. Wu, Y.K. Wu
FEL/Duke University, Durham, North Carolina, USA

Hefei Light Source (HLS) is a dedicated synchrotron radiation research facility. It is now undergoing a major upgrade. To obtain a better performance of the light source, a longitudinal feedback system will be developed as part of the upgrade project to cure the coupled bunch mode instabilities. In this work, we present a design of the LFB kicker, a waveguide overloaded cavity with two input and two output ports. The cavity design specifications include a central frequency of 969 MHz (4.75 RF frequency), a bandwidth of more than 100 MHz, and a high shunt impedance of 1200 Ω. A study is carried out to find the dependence of the cavity performance on a few critical geometric parameters of the cavity. Since the shape of the vacuum chamber of the HLS storage ring is octagon, a transition from a circular vacuum chamber to an octagon one is built into the end pieces of the cavity to minimize the total cavity length. To lower the required amplifier power, the structure is optimized to obtain a high shunt impedance. The higher order modes of the kicker cavity are also considered during the design.

TUOCS6

An VUV FEL for Producing Circularly Polarized Compton Gamma-ray Beams in the 70 to 100 MeV Region

778

Y.K. Wu, J.Y. Li, S.F. Mikhailov, V. Popov, G. Swift, P.W. Wallace, W. Wu
FEL/Duke University, Durham, North Carolina, USA
S. Huang
PKU/IHIP, Beijing, People's Republic of China

Funding: This work is supported in part by the US DOE grant no. DE-FG02-97ER41033.
Recently, the Duke optical klystron FEL (OK-5 FEL) has been commissioned to produce lasing in the VUV region (191 - 193 nm), overcoming substantial laser cavity loss due to low reflectivity of the VUV FEL mirrors. With two OK-5 FEL wigglers separated by more than 20 meters in a non-optimal configuration, an adequate FEL gain was realized by operating the Duke storage ring with a high single-bunch current (30 to 50 mA). This VUV FEL has enabled us to produce circularly polarized Compton gamma-ray beams in the 70 to 100 MeV region at the High Intensity Gamma-ray Source (HIGS), Duke University. This high energy gamma-ray beam capability will create new opportunities for both fundamental and applied research at HIGS. In this work, we report our experience of VUV FEL lasing with a high single-bunch current and first production of gamma-ray beams in the 70 to 100 MeV region.

Slides TUOCS6 [2.768 MB]

Paper	Title	Page
MOP269	Design of Longitudinal Feedback Kicker for HLS Storage Ring	612
	W. Xu, D.H. He USTC/NSRL, Hefei, Anhui, People's Republic of China W. Wu, Y.K. Wu FEL/Duke University, Durham, North Carolina, USA
	Hefei Light Source (HLS) is a dedicated synchrotron radiation research facility. It is now undergoing a major upgrade. To obtain a better performance of the light source, a longitudinal feedback system will be developed as part of the upgrade project to cure the coupled bunch mode instabilities. In this work, we present a design of the LFB kicker, a waveguide overloaded cavity with two input and two output ports. The cavity design specifications include a central frequency of 969 MHz (4.75 RF frequency), a bandwidth of more than 100 MHz, and a high shunt impedance of 1200 Ω. A study is carried out to find the dependence of the cavity performance on a few critical geometric parameters of the cavity. Since the shape of the vacuum chamber of the HLS storage ring is octagon, a transition from a circular vacuum chamber to an octagon one is built into the end pieces of the cavity to minimize the total cavity length. To lower the required amplifier power, the structure is optimized to obtain a high shunt impedance. The higher order modes of the kicker cavity are also considered during the design.

TUOCS6	An VUV FEL for Producing Circularly Polarized Compton Gamma-ray Beams in the 70 to 100 MeV Region	778
	Y.K. Wu, J.Y. Li, S.F. Mikhailov, V. Popov, G. Swift, P.W. Wallace, W. Wu FEL/Duke University, Durham, North Carolina, USA S. Huang PKU/IHIP, Beijing, People's Republic of China
	Funding: This work is supported in part by the US DOE grant no. DE-FG02-97ER41033. Recently, the Duke optical klystron FEL (OK-5 FEL) has been commissioned to produce lasing in the VUV region (191 - 193 nm), overcoming substantial laser cavity loss due to low reflectivity of the VUV FEL mirrors. With two OK-5 FEL wigglers separated by more than 20 meters in a non-optimal configuration, an adequate FEL gain was realized by operating the Duke storage ring with a high single-bunch current (30 to 50 mA). This VUV FEL has enabled us to produce circularly polarized Compton gamma-ray beams in the 70 to 100 MeV region at the High Intensity Gamma-ray Source (HIGS), Duke University. This high energy gamma-ray beam capability will create new opportunities for both fundamental and applied research at HIGS. In this work, we report our experience of VUV FEL lasing with a high single-bunch current and first production of gamma-ray beams in the 70 to 100 MeV region.
	Slides TUOCS6 [2.768 MB]