SRF2013 - List of Authors (Dai, J.)

Paper

Title

Page

BNL SRF Gun Commissioning

155

W. Xu, Z. Altinbas, S.A. Belomestnykh, I. Ben-Zvi, J. Dai, S. Deonarine, D.M. Gassner, H. Hahn, J.P. Jamilkowski, P. Kankiya, D. Kayran, N. Laloudakis, L. Masi, G.T. McIntyre, D. Pate, D. Phillips, T. Seda, K.S. Smith, A.N. Steszyn, T.N. Tallerico, R. Than, R.J. Todd, D. Weiss, A. Zaltsman
BNL, Upton, Long Island, New York, USA
I. Ben-Zvi, J. Dai
Stony Brook University, Stony Brook, USA

Funding: This work is supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
The 704 MHz superconducting RF gun for the R&D ERL project is under comissioning at BNL. Since last November, the SRF gun has been conditioned and demonstrated an operational accelerating voltage of 2 MV (an accelerating gradient of 23.5 MV/m). Preparations for the cathode insertion are in final stages and we expect the gun to generate the first electron beam this summer. This paper discusses the BNL SRF gun system,and the results of the SRF gun commissioning.

MOP028

Theoretical Study of the External Q Factor Of a Dual-Feed Coupling for Superconducting RF Cavities

J. Dai
Stony Brook University, Stony Brook, USA
S.A. Belomestnykh, I. Ben-Zvi, W. Xu
BNL, Upton, Long Island, New York, USA

Funding: This work is supported by both Brookhaven Science Associates, LLC under Contract No.DE-AC02-98CH10886 and the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
A theoretical model based on network analysis is proposed here to study the external quality factor (Qext) of a dual-feed coupling for superconducting radio-frequency (SRF) cavities. The calculation results from the model shows that the external Q factor of a dual-feed coupling system changes with the phase difference of the two coupling arms with a period of 360 degrees. If we change the phase of the two arms simultaneously, the external Q factor would change with a period of 180 degrees.

THP055

Ferrite Covered Ceramic Break HOM Damper

1040

H. Hahn, S.A. Belomestnykh, I. Ben-Zvi, L.R. Hammons, V. Litvinenko, R.J. Todd, D. Weiss, W. Xu
BNL, Upton, Long Island, New York, USA
A. Burrill
HZB, Berlin, Germany
J. Dai
Stony Brook University, Stony Brook, USA

Funding: Work supported by Brookhaven Science Associates, LLC under contract no. DE-AC02-98CH10886 with the DOE.
The Brookhaven Energy Recovery Linac (ERL) is operated as R&D setup for high-current, high charge electron beams. It is comprised of a superconducting (SC) five-cell cavity and a half-cell SC photoinjector electron RF gun. Achieving the performance objectives requires effective HOM damping in the linac and gun cavity. Among the HOM dampers being developed is a beam-tube type HOM load for the electron gun consisting of a ceramic break surrounded by ferrite tiles. This design is innovative in its approach and achieves a variety of ends including broadband HOM damping and protection of the superconducting cavity from potential damage of the separately cooled ferrite tiles. The damper properties are described by the coupling impedance to a beam and the external Q to constrain the unloaded mode Q’s. Measured results for the gun damper at room and superconducting temperatures are presented

Paper	Title	Page
MOP027	BNL SRF Gun Commissioning	155
	W. Xu, Z. Altinbas, S.A. Belomestnykh, I. Ben-Zvi, J. Dai, S. Deonarine, D.M. Gassner, H. Hahn, J.P. Jamilkowski, P. Kankiya, D. Kayran, N. Laloudakis, L. Masi, G.T. McIntyre, D. Pate, D. Phillips, T. Seda, K.S. Smith, A.N. Steszyn, T.N. Tallerico, R. Than, R.J. Todd, D. Weiss, A. Zaltsman BNL, Upton, Long Island, New York, USA I. Ben-Zvi, J. Dai Stony Brook University, Stony Brook, USA
	Funding: This work is supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE. The 704 MHz superconducting RF gun for the R&D ERL project is under comissioning at BNL. Since last November, the SRF gun has been conditioned and demonstrated an operational accelerating voltage of 2 MV (an accelerating gradient of 23.5 MV/m). Preparations for the cathode insertion are in final stages and we expect the gun to generate the first electron beam this summer. This paper discusses the BNL SRF gun system,and the results of the SRF gun commissioning.

MOP028	Theoretical Study of the External Q Factor Of a Dual-Feed Coupling for Superconducting RF Cavities
	J. Dai Stony Brook University, Stony Brook, USA S.A. Belomestnykh, I. Ben-Zvi, W. Xu BNL, Upton, Long Island, New York, USA
	Funding: This work is supported by both Brookhaven Science Associates, LLC under Contract No.DE-AC02-98CH10886 and the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. A theoretical model based on network analysis is proposed here to study the external quality factor (Qext) of a dual-feed coupling for superconducting radio-frequency (SRF) cavities. The calculation results from the model shows that the external Q factor of a dual-feed coupling system changes with the phase difference of the two coupling arms with a period of 360 degrees. If we change the phase of the two arms simultaneously, the external Q factor would change with a period of 180 degrees.

THP055	Ferrite Covered Ceramic Break HOM Damper	1040
	H. Hahn, S.A. Belomestnykh, I. Ben-Zvi, L.R. Hammons, V. Litvinenko, R.J. Todd, D. Weiss, W. Xu BNL, Upton, Long Island, New York, USA A. Burrill HZB, Berlin, Germany J. Dai Stony Brook University, Stony Brook, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under contract no. DE-AC02-98CH10886 with the DOE. The Brookhaven Energy Recovery Linac (ERL) is operated as R&D setup for high-current, high charge electron beams. It is comprised of a superconducting (SC) five-cell cavity and a half-cell SC photoinjector electron RF gun. Achieving the performance objectives requires effective HOM damping in the linac and gun cavity. Among the HOM dampers being developed is a beam-tube type HOM load for the electron gun consisting of a ceramic break surrounded by ferrite tiles. This design is innovative in its approach and achieves a variety of ends including broadband HOM damping and protection of the superconducting cavity from potential damage of the separately cooled ferrite tiles. The damper properties are described by the coupling impedance to a beam and the external Q to constrain the unloaded mode Q’s. Measured results for the gun damper at room and superconducting temperatures are presented