SRF2013 - List of Authors (Shemelin, V.D.)

Paper

Title

Page

Cornell’s Beam Line Higher Order Mode Absorbers

1027

R.G. Eichhorn, J.V. Conway, Y. He, Y. Li, T.I. O'Connel, P. Quigley, J. Sears, N.R.A. Valles
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
V.D. Shemelin
Cornell University, Ithaca, New York, USA

Efficient damping of the higher-order modes (HOMs) of the superconducting cavities is essential for the proposed energy recovery linac at Cornell that aims for high beam currents and short bunches. Designing these HOM beamline absorbers has been a long endeavor, sometimes including disappointing results. We will review the design, the findings on the prototype and the final choices made for the 7 HOM absorbers being built for the main linac cryomodule (MLC) prototype.

MOP086

Integration, Commissioning and Cryogenics Performance of the ERL Cryomodule Installed on ALICE-ERL Facility at STFC Daresbury Laboratory, UK

349

S.M. Pattalwar, R.K. Buckley, P.A. Corlett, P. Goudket, A.R. Goulden, A.J. May, P.A. McIntosh, A.E. Wheelhouse
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
S.A. Belomestnykh
BNL, Upton, Long Island, New York, USA
A. Büchner, F.G. Gabriel, P. Michel
HZDR, Dresden, Germany
E.P. Chojnacki, J.V. Conway, R.G. Eichhorn, G.H. Hoffstaetter, M. Liepe, H. Padamsee, P. Quigley, J. Sears, V.D. Shemelin
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
M.A. Cordwell, T.J. Jones, L. Ma, A.J. Moss, J. Strachan
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
J.N. Corlett, D. Li, S.M. Lidia
LBNL, Berkeley, California, USA
T. Kimura
Stanford University, Stanford, California, USA
R.E. Laxdal
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
J.K. Sekutowicz
DESY, Hamburg, Germany
T.J. Smith
SLAC, Menlo Park, California, USA

On successful assembly and preliminary testing of an optimised SRF cryomodule for application on ERL accelerators, which is being developed through an international collaboration the cryomodule has been installed on the 35 MeV ALICE (Accelerators and Lasers in Combined Experiments) Energy Recovery Linac (ERL) facility at STFC Daresbury Laboratory. Existing cryogenic infrastructure has a capacity to deliver approximately 120 W cooling power at 2 K, but the HOM (Higher Order Mode) absorbers, the thermal intercepts for the high power RF couplers and the radiation shield in the cryomodule are designed to be cooled (to 5 K and 80 K) with gaseous helium instead of liquid nitrogen. As a result the cryogenic infrastructure for ALICE had to be modified to meet these additional requirements. In this paper we describe our experience with the process of integration and the cryogenic commissioning, and present some initial results.

THIOB02

High Q Cavities for the Cornell ERL Main Linac

844

R.G. Eichhorn, B. Bullock, B. Clasby, B. Elmore, F. Furuta, A. Ganshin, G.M. Ge, D. Gonnella, D.L. Hall, Y. He, K.M.V. Ho, G.H. Hoffstaetter, J.J. Kaufman, M. Liepe, T.I. O'Connel, S. Posen, P. Quigley, J. Sears, V.D. Shemelin, E.N. Smith, V. Veshcherevich
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

While SRF research for linear colliders was focused on achieving high gradients, Cornell’s proposal for an energy recovery linac (ERL) demanded for low cw losses. Starting several years ago, a high-Q R&D phase was launched that led to remarkable results recently: A fully dressed cavity (7 cells, 1.3 GHz) with side-mounted input coupler and beamline HOM absorbers achieved a Q of 3.5·10¹⁰ ((16 MV/m, 1.8 K). This talk will review the staged approach we have chosen in testing a single cavity in a horizontal short cryomodule (HTC), report results on each step and conclude on our findings about preserving high Q from vertical testing. We also discuss the production of six additional cavities as we progress toward constructing a full 6-cavity cryomodule as a prototype for Cornell’s main linac module

Slides THIOB02 [8.378 MB]

THP007

Cornell's ERL Cavity Production

909

R.G. Eichhorn, B. Bullock, B. Clasby, B. Elmore, F. Furuta, G.H. Hoffstaetter, J.J. Kaufman, B.M. Kilpatrick, J. Sears, V.D. Shemelin
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
T. Kürzeder
TU Darmstadt, Darmstadt, Germany

The phase 1 R&D program launched in preparation to building a 5 GeV Energy Recovery Linac (ERL) at Cornell, a full main linac cryomodule is currently built, housing six 7-cell cavities. In order to control the beam break-up limit, the shape of the cavity was highly optimized and stringent tolerances on the cavity production were targeted. We will report on the details of the cavity production, the accuracy of the cups forming the individual cells, the trimming procedure for the dumbbells, the cavity tuning and final accuracy of the cavity concerning field flatness, resonant frequency and overall length within this small series production.

THP073

HOM Dampers and Waveguide for the Short Pulse X-Ray (SPX) Project

1098

G.J. Waldschmidt, B. Brajuskovic, D.J. Bromberek, J.D. Fuerst, J.P. Holzbauer, A. Nassiri, Y. Shiroyanagi, G. Wu
ANL, Argonne, USA
V.D. Shemelin
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: Work supported by U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
The production of HOM dampers for the superconducting SPX cavities has been undertaken at the Advanced Photon Source. The dampers are vacuum compatible loads that utilize a four wedge design in WR284 rectangular waveguide. The rf lossy material consists of hexoloy silicon carbide (SiC) due to its suitable mechanical and electrical material properties. Issues regarding manufacturing consist of initial SiC material failure due to fabrication stresses as well as substandard soldering bonds of the SiC to the copper damper bodies. In addition, integration into the cryomodule consists of rf, thermal, and mechanical design considerations of the dampers and the waveguide transmission lines. An analysis of the manufacturing and integration issues and remedies are discussed further in this paper.

Paper	Title	Page
THP052	Cornell’s Beam Line Higher Order Mode Absorbers	1027
	R.G. Eichhorn, J.V. Conway, Y. He, Y. Li, T.I. O'Connel, P. Quigley, J. Sears, N.R.A. Valles Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA V.D. Shemelin Cornell University, Ithaca, New York, USA
	Efficient damping of the higher-order modes (HOMs) of the superconducting cavities is essential for the proposed energy recovery linac at Cornell that aims for high beam currents and short bunches. Designing these HOM beamline absorbers has been a long endeavor, sometimes including disappointing results. We will review the design, the findings on the prototype and the final choices made for the 7 HOM absorbers being built for the main linac cryomodule (MLC) prototype.

MOP086	Integration, Commissioning and Cryogenics Performance of the ERL Cryomodule Installed on ALICE-ERL Facility at STFC Daresbury Laboratory, UK	349
	S.M. Pattalwar, R.K. Buckley, P.A. Corlett, P. Goudket, A.R. Goulden, A.J. May, P.A. McIntosh, A.E. Wheelhouse STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom S.A. Belomestnykh BNL, Upton, Long Island, New York, USA A. Büchner, F.G. Gabriel, P. Michel HZDR, Dresden, Germany E.P. Chojnacki, J.V. Conway, R.G. Eichhorn, G.H. Hoffstaetter, M. Liepe, H. Padamsee, P. Quigley, J. Sears, V.D. Shemelin Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA M.A. Cordwell, T.J. Jones, L. Ma, A.J. Moss, J. Strachan STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom J.N. Corlett, D. Li, S.M. Lidia LBNL, Berkeley, California, USA T. Kimura Stanford University, Stanford, California, USA R.E. Laxdal TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada J.K. Sekutowicz DESY, Hamburg, Germany T.J. Smith SLAC, Menlo Park, California, USA
	On successful assembly and preliminary testing of an optimised SRF cryomodule for application on ERL accelerators, which is being developed through an international collaboration the cryomodule has been installed on the 35 MeV ALICE (Accelerators and Lasers in Combined Experiments) Energy Recovery Linac (ERL) facility at STFC Daresbury Laboratory. Existing cryogenic infrastructure has a capacity to deliver approximately 120 W cooling power at 2 K, but the HOM (Higher Order Mode) absorbers, the thermal intercepts for the high power RF couplers and the radiation shield in the cryomodule are designed to be cooled (to 5 K and 80 K) with gaseous helium instead of liquid nitrogen. As a result the cryogenic infrastructure for ALICE had to be modified to meet these additional requirements. In this paper we describe our experience with the process of integration and the cryogenic commissioning, and present some initial results.

THIOB02	High Q Cavities for the Cornell ERL Main Linac	844
	R.G. Eichhorn, B. Bullock, B. Clasby, B. Elmore, F. Furuta, A. Ganshin, G.M. Ge, D. Gonnella, D.L. Hall, Y. He, K.M.V. Ho, G.H. Hoffstaetter, J.J. Kaufman, M. Liepe, T.I. O'Connel, S. Posen, P. Quigley, J. Sears, V.D. Shemelin, E.N. Smith, V. Veshcherevich Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	While SRF research for linear colliders was focused on achieving high gradients, Cornell’s proposal for an energy recovery linac (ERL) demanded for low cw losses. Starting several years ago, a high-Q R&D phase was launched that led to remarkable results recently: A fully dressed cavity (7 cells, 1.3 GHz) with side-mounted input coupler and beamline HOM absorbers achieved a Q of 3.5·10¹⁰ ((16 MV/m, 1.8 K). This talk will review the staged approach we have chosen in testing a single cavity in a horizontal short cryomodule (HTC), report results on each step and conclude on our findings about preserving high Q from vertical testing. We also discuss the production of six additional cavities as we progress toward constructing a full 6-cavity cryomodule as a prototype for Cornell’s main linac module
	Slides THIOB02 [8.378 MB]

THP007	Cornell's ERL Cavity Production	909
	R.G. Eichhorn, B. Bullock, B. Clasby, B. Elmore, F. Furuta, G.H. Hoffstaetter, J.J. Kaufman, B.M. Kilpatrick, J. Sears, V.D. Shemelin Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA T. Kürzeder TU Darmstadt, Darmstadt, Germany
	The phase 1 R&D program launched in preparation to building a 5 GeV Energy Recovery Linac (ERL) at Cornell, a full main linac cryomodule is currently built, housing six 7-cell cavities. In order to control the beam break-up limit, the shape of the cavity was highly optimized and stringent tolerances on the cavity production were targeted. We will report on the details of the cavity production, the accuracy of the cups forming the individual cells, the trimming procedure for the dumbbells, the cavity tuning and final accuracy of the cavity concerning field flatness, resonant frequency and overall length within this small series production.

THP073	HOM Dampers and Waveguide for the Short Pulse X-Ray (SPX) Project	1098
	G.J. Waldschmidt, B. Brajuskovic, D.J. Bromberek, J.D. Fuerst, J.P. Holzbauer, A. Nassiri, Y. Shiroyanagi, G. Wu ANL, Argonne, USA V.D. Shemelin Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: Work supported by U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357. The production of HOM dampers for the superconducting SPX cavities has been undertaken at the Advanced Photon Source. The dampers are vacuum compatible loads that utilize a four wedge design in WR284 rectangular waveguide. The rf lossy material consists of hexoloy silicon carbide (SiC) due to its suitable mechanical and electrical material properties. Issues regarding manufacturing consist of initial SiC material failure due to fabrication stresses as well as substandard soldering bonds of the SiC to the copper damper bodies. In addition, integration into the cryomodule consists of rf, thermal, and mechanical design considerations of the dampers and the waveguide transmission lines. An analysis of the manufacturing and integration issues and remedies are discussed further in this paper.