SRF2011 - List of Authors (Wu, Q.)

Paper

Title

Page

Design of the Fundamental Power Coupler and Photocathode Inserts for the 112 MHz Superconducting Electron Gun

83

T. Xin
Stony Brook University, Stony Brook, USA
S.A. Belomestnykh, I. Ben-Zvi, X. Chang, X. Liang, T. Rao, J. Skaritka, E. Wang, Q. Wu
BNL, Upton, Long Island, New York, USA

Funding: Work is supported at Stony Brook University under grant DE-SC0005713 by the US DOE, at BNL by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
A 112MHz superconducting quarter-wave resonator electron gun will be used as the injector of the Coherent Electron Cooling (CEC) proof-of-principle experiment at BNL. Furthermore, this electron gun can be the testing cavity for various photocathodes. In this paper, we present the design of the Fundamental Power Coupler (FPC) and the cathode stalks designated to the future experiments. The axial waveguide structure FPC has the properties of tunable coupling factor and small interference to the electron beam output. The optimization of the coupling factor and the location of the FPC are discussed in detail. Two types of cathode stalks are discussed. Special shape of the stalk is applied in order to minimize the RF power loss. The location of cathode plane is also optimized to enable the extraction of low emittance beam.

MOPO054

Superconducting 112 MHz QWR Electron Gun

223

S.A. Belomestnykh, I. Ben-Zvi, X. Chang, X. Liang, T. Rao, J. Skaritka, R. Than, Q. Wu, T. Xin
BNL, Upton, Long Island, New York, USA
C.H. Boulware, T.L. Grimm, B. Siegel, M.J. Winowski
Niowave, Inc., Lansing, Michigan, USA

Funding: Work is supported at BNL by BSA, LLC under U.S. DOE Contract No. DE-AC02-98CH10886, at Stony Brook University by U.S. DOE grant DE-SC0005713, at Niowave by U.S. DOE SBIR contract No. DE-FG02-07ER84861
Brookhaven National Laboratory and Niowave, Inc. have designed and fabricated a superconducting 112 MHz quarter-wave resonator (QWR) electron gun. The first cold test of the QWR cryomodule has been completed at Niowave. The paper describes the cryomodule design, presents the cold test results, and outline plans to upgrade the cryomodule. Future experiments include studies of different photocathodes and use for the coherent electron cooling proof-of-principle experiment. Two cathode stalk options, one for multi-alkali photocathodes and the other one for a diamond-amplified photocathode, are discussed.

Poster MOPO054 [3.299 MB]

THPO007

Novel Deflecting Cavity Design for eRHIC

707

Q. Wu, S.A. Belomestnykh, I. Ben-Zvi
BNL, Upton, Long Island, New York, USA

Funding: Work is supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
To prevent significant loss of the luminosity due to large crossing angle in the future ERL based Electron Ion Collider at BNL (eRHIC), there is a demand for crab cavities. In this article, we will present a novel design of the deflecting/crabbing 200 MHz superconducting RF cavity that will fulfill the requirements of eRHIC. The quarter-wave resonator structure of the new cavity possesses many advantages, such as compact size, high Rt/Q, the absence of same order mode and lower order mode, and easy higher order mode damping. We will present the properties and characteristics of the new cavity in detail.

Paper	Title	Page
MOPO014	Design of the Fundamental Power Coupler and Photocathode Inserts for the 112 MHz Superconducting Electron Gun	83
	T. Xin Stony Brook University, Stony Brook, USA S.A. Belomestnykh, I. Ben-Zvi, X. Chang, X. Liang, T. Rao, J. Skaritka, E. Wang, Q. Wu BNL, Upton, Long Island, New York, USA
	Funding: Work is supported at Stony Brook University under grant DE-SC0005713 by the US DOE, at BNL by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE. A 112MHz superconducting quarter-wave resonator electron gun will be used as the injector of the Coherent Electron Cooling (CEC) proof-of-principle experiment at BNL. Furthermore, this electron gun can be the testing cavity for various photocathodes. In this paper, we present the design of the Fundamental Power Coupler (FPC) and the cathode stalks designated to the future experiments. The axial waveguide structure FPC has the properties of tunable coupling factor and small interference to the electron beam output. The optimization of the coupling factor and the location of the FPC are discussed in detail. Two types of cathode stalks are discussed. Special shape of the stalk is applied in order to minimize the RF power loss. The location of cathode plane is also optimized to enable the extraction of low emittance beam.

MOPO054	Superconducting 112 MHz QWR Electron Gun	223
	S.A. Belomestnykh, I. Ben-Zvi, X. Chang, X. Liang, T. Rao, J. Skaritka, R. Than, Q. Wu, T. Xin BNL, Upton, Long Island, New York, USA C.H. Boulware, T.L. Grimm, B. Siegel, M.J. Winowski Niowave, Inc., Lansing, Michigan, USA
	Funding: Work is supported at BNL by BSA, LLC under U.S. DOE Contract No. DE-AC02-98CH10886, at Stony Brook University by U.S. DOE grant DE-SC0005713, at Niowave by U.S. DOE SBIR contract No. DE-FG02-07ER84861 Brookhaven National Laboratory and Niowave, Inc. have designed and fabricated a superconducting 112 MHz quarter-wave resonator (QWR) electron gun. The first cold test of the QWR cryomodule has been completed at Niowave. The paper describes the cryomodule design, presents the cold test results, and outline plans to upgrade the cryomodule. Future experiments include studies of different photocathodes and use for the coherent electron cooling proof-of-principle experiment. Two cathode stalk options, one for multi-alkali photocathodes and the other one for a diamond-amplified photocathode, are discussed.
	Poster MOPO054 [3.299 MB]

THPO007	Novel Deflecting Cavity Design for eRHIC	707
	Q. Wu, S.A. Belomestnykh, I. Ben-Zvi BNL, Upton, Long Island, New York, USA
	Funding: Work is supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE. To prevent significant loss of the luminosity due to large crossing angle in the future ERL based Electron Ion Collider at BNL (eRHIC), there is a demand for crab cavities. In this article, we will present a novel design of the deflecting/crabbing 200 MHz superconducting RF cavity that will fulfill the requirements of eRHIC. The quarter-wave resonator structure of the new cavity possesses many advantages, such as compact size, high Rt/Q, the absence of same order mode and lower order mode, and easy higher order mode damping. We will present the properties and characteristics of the new cavity in detail.