SRF2011 - List of Authors (Belomestnykh, S.A.)

Paper

Title

Page

Survey of SRF Guns

23

S.A. Belomestnykh
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.
Developing Superconducting RF (SRF) electron guns is an active field with several laboratories working on different gun designs. While the first guns were based on elliptic cavity geometries, Quarter Wave Resonator (QWR) option is gaining popularity. QWRs are especially well suited for producing beams with high charge per bunch. In this talk we will describe recent progress in developing both types of SRF guns.

Slides MOIOB04 [8.668 MB]

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]

MOPO067

CW Measurements of Cornell LLRF System at HoBiCaT

262

A. Neumann, W. Anders, R. Görgen, J. Knobloch, O. Kugeler
HZB, Berlin, Germany
S.A. Belomestnykh
BNL, Upton, Long Island, New York, USA
J. Dobbins, R.P.K. Kaplan, M. Liepe, C.R. Strohman
CLASSE, Ithaca, New York, USA

Funding: Work funded by the Bundesministerium für Bildung und Forschung and Land Berlin.
In Energy Recovery Linacs, such as the Cornell ERL or BERLinPro, the main linac cavities are operated in CW at low beam-loading. The choice of the external Q is given by two competing factors: The achievable field stability and the maximum provided RF power. To determine the optimum external Q, LLRF measurements with the Cornell system were performed at HoBiCaT to study the field stability at given microphonics detuning of a TESLA cavity for different gain settings and external Q values. Stable operation at external Q up to 2·10⁸ was demonstrated with field's phase stability of 0.02 degrees.

TUPO010

Conditioning the Fundamental Power Coupler for ERL SRF Gun

371

W. Xu, Z. Altinbas, S.A. Belomestnykh, I. Ben-Zvi, A. Burrill, S. Deonarine, D.M. Gassner, J.P. Jamilkowski, P. Kankiya, D. Kayran, N. Laloudakis, L. Masi, G.T. McIntyre, D. Pate, D. Phillips, T. Seda, A.N. Steszyn, T.N. Tallerico, R.J. Todd, D. Weiss, A. Zaltsman
BNL, Upton, Long Island, New York, USA
M.D. Cole, G.J. Whitbeck
AES, Medford, NY, USA

Funding: This work is supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
The 703 MHz superconducting gun for the BNL Energy Recovery Linac (ERL) prototype has two fundamental power couplers (FPCs), and each of them will deliver up to 500 kW of CW RF power. In order to prepare the couplers for high power RF service and process multipacting, the FPCs should be conditioned prior to installation into the gun cryomodule. A conditioning cart based test stand, which includes a vacuum pumping system, controllable bake-out system, diagnostics, interlocks and data log system has been designed, constructed and commissioned by collaboration of BNL and AES. This paper presents FPC conditioning cart systems and the conditioning process.

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.

TUPO013

Assembly of the International ERL Cryomodule at Daresbury Laboratory

382

P.A. McIntosh, R. Bate, P. Goudket, J.F. Orrett, S.M. Pattalwar
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
S.A. Belomestnykh, M. Liepe, H. Padamsee, P. Quigley, J. Sears, V.D. Shemelin, V. Veshcherevich
CLASSE, Ithaca, New York, USA
A. Büchner, F.G. Gabriel, P. Michel
HZDR, Dresden, Germany
M.A. Cordwell, T.J. Jones, J. Strachan
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
J.N. Corlett, D. Li, S.M. Lidia
LBNL, Berkeley, California, USA
T. Kimura, T.I. Smith
Stanford University, Stanford, California, USA
R.E. Laxdal
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
D. Proch, J.K. Sekutowicz
DESY, Hamburg, Germany

The collaborative development of an optimised cavity/cryomodule solution for application on ERL facilities is nearing completion. This paper outlines the progress of the module assembly and details the processes used for final cavity string integration. The preparation and installation of the high power couplers will be described, as will that of the HOM loads. The testing and integration of the various sub-components of the cryomodule are also detailed in this paper.

Paper	Title	Page
MOIOB04	Survey of SRF Guns	23
	S.A. Belomestnykh 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. Developing Superconducting RF (SRF) electron guns is an active field with several laboratories working on different gun designs. While the first guns were based on elliptic cavity geometries, Quarter Wave Resonator (QWR) option is gaining popularity. QWRs are especially well suited for producing beams with high charge per bunch. In this talk we will describe recent progress in developing both types of SRF guns.
	Slides MOIOB04 [8.668 MB]

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]

MOPO067	CW Measurements of Cornell LLRF System at HoBiCaT	262
	A. Neumann, W. Anders, R. Görgen, J. Knobloch, O. Kugeler HZB, Berlin, Germany S.A. Belomestnykh BNL, Upton, Long Island, New York, USA J. Dobbins, R.P.K. Kaplan, M. Liepe, C.R. Strohman CLASSE, Ithaca, New York, USA
	Funding: Work funded by the Bundesministerium für Bildung und Forschung and Land Berlin. In Energy Recovery Linacs, such as the Cornell ERL or BERLinPro, the main linac cavities are operated in CW at low beam-loading. The choice of the external Q is given by two competing factors: The achievable field stability and the maximum provided RF power. To determine the optimum external Q, LLRF measurements with the Cornell system were performed at HoBiCaT to study the field stability at given microphonics detuning of a TESLA cavity for different gain settings and external Q values. Stable operation at external Q up to 2·10⁸ was demonstrated with field's phase stability of 0.02 degrees.

TUPO010	Conditioning the Fundamental Power Coupler for ERL SRF Gun	371
	W. Xu, Z. Altinbas, S.A. Belomestnykh, I. Ben-Zvi, A. Burrill, S. Deonarine, D.M. Gassner, J.P. Jamilkowski, P. Kankiya, D. Kayran, N. Laloudakis, L. Masi, G.T. McIntyre, D. Pate, D. Phillips, T. Seda, A.N. Steszyn, T.N. Tallerico, R.J. Todd, D. Weiss, A. Zaltsman BNL, Upton, Long Island, New York, USA M.D. Cole, G.J. Whitbeck AES, Medford, NY, USA
	Funding: This work is supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE. The 703 MHz superconducting gun for the BNL Energy Recovery Linac (ERL) prototype has two fundamental power couplers (FPCs), and each of them will deliver up to 500 kW of CW RF power. In order to prepare the couplers for high power RF service and process multipacting, the FPCs should be conditioned prior to installation into the gun cryomodule. A conditioning cart based test stand, which includes a vacuum pumping system, controllable bake-out system, diagnostics, interlocks and data log system has been designed, constructed and commissioned by collaboration of BNL and AES. This paper presents FPC conditioning cart systems and the conditioning process.

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.

TUPO013	Assembly of the International ERL Cryomodule at Daresbury Laboratory	382
	P.A. McIntosh, R. Bate, P. Goudket, J.F. Orrett, S.M. Pattalwar STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom S.A. Belomestnykh, M. Liepe, H. Padamsee, P. Quigley, J. Sears, V.D. Shemelin, V. Veshcherevich CLASSE, Ithaca, New York, USA A. Büchner, F.G. Gabriel, P. Michel HZDR, Dresden, Germany M.A. Cordwell, T.J. Jones, J. Strachan STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom J.N. Corlett, D. Li, S.M. Lidia LBNL, Berkeley, California, USA T. Kimura, T.I. Smith Stanford University, Stanford, California, USA R.E. Laxdal TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada D. Proch, J.K. Sekutowicz DESY, Hamburg, Germany
	The collaborative development of an optimised cavity/cryomodule solution for application on ERL facilities is nearing completion. This paper outlines the progress of the module assembly and details the processes used for final cavity string integration. The preparation and installation of the high power couplers will be described, as will that of the HOM loads. The testing and integration of the various sub-components of the cryomodule are also detailed in this paper.