PAC2013 - List of Authors (Sears, J.)

Paper	Title	Page
WEPAC11	Cornell's Main Linac Cryo-module Prototype	811
	R.G. Eichhorn, G.M. Ge, Y. He, G.H. Hoffstaetter, M. Liepe, T. O'Connel, P. Quigley, D.M. Sabol, J. Sears, E.N. Smith, V. Veshcherevich Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: Supported by NSF award DMR-0807731 In preparation to built an energy-recovery linac (ERL) based synchrotron-light facility at Cornell University which can provide greatly improved X-ray beams due to the high electron-beam quality that is available from a linac, a phase 1 R&D program was launched, adressing critical challenges in the design. One of them being a full linac cryo-module, housing 6 superconducting cavities (operated at 1.8 K in cw mode), 7 HOM absorbers and 1 magnet/ BPM section. The final design will be presented and a report on the fabrication status that started in late 2012 will be given

WEPAC13	Achieving High Accuracy in Cornell's ERL Cavity Production	817
	R.G. Eichhorn, B. Bullock, B. Clasby, J.J. Kaufman, B.M. Kilpatrick, S. Posen, 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
	Funding: Supported by NSF award DMR-0807731 The phase 1 R&D program launched in preparation to building a 5 GeV Enery 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.

THPAC19	Temperature Dependence of Photoemission from Copper and Niobium	1184
	J.R. Harris CSU, Fort Collins, Colorado, USA C.W. Bennett, M.D. Galt, A.D. Holmes, A. Kara, R. Swent NPS, Monterey, California, USA J.W. Lewellen LANL, Los Alamos, New Mexico, USA J. Sears Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: This work was funded by the Office of Naval Research and the High Energy Laser Joint Technology Office. Photocathodes remain the principal electron sources for many particle accelerators. With the increasing interest in the use of superconducting radiofrequency electron guns, it is important to understand how operation at cryogenic temperatures affects the performance of photocathodes. Here we report measurements of the quantum efficiency of copper and niobium under illumination with 266 nm light at temperatures between 85K and 400K. The quantum efficiency of copper was found to vary strongly over this range, while there was only a minimal change in the quantum efficiency of niobium.

THPMA07	Cryomodule Performance of the Main Linac Prototype Cavity for Cornell's Energy Recovery Linac	1367
	N.R.A. Valles, R.G. Eichhorn, F. Furuta, G.M. Ge, D. Gonnella, D.L. Hall, Y. He, K.M.V. Ho, G.H. Hoffstaetter, M. Liepe, T.I. O'Connell, S. Posen, P. Quigley, J. Sears, V. Veshcherevich Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: NSF Grants: NSF DMR-0807731 and NSF PHY-1002467 Energy Recovery Linacs (ERLs) require strong damping of higher-order modes in main linac cavities to avoid beam loss from beam break-up effects. In addition, the cavities need to have very high intrinsic quality factors to minimize the size of cryogenic plants in CW cavity operation. We present world record results for a fully equipped multicell cavity in a cryomodule, reaching intrinsic quality factors at operating accelerating field of Q₀(E =16.2 MV/m, 1.8~K) > 6.0\ee10 and Q₀(E =16.2 MV/m, 1.6~K) = 1.0\ee{11}, corresponding to a residual surface resistance of 1.1~nΩ.

Paper

Title

Page

Cornell's Main Linac Cryo-module Prototype

811

R.G. Eichhorn, G.M. Ge, Y. He, G.H. Hoffstaetter, M. Liepe, T. O'Connel, P. Quigley, D.M. Sabol, J. Sears, E.N. Smith, V. Veshcherevich
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: Supported by NSF award DMR-0807731
In preparation to built an energy-recovery linac (ERL) based synchrotron-light facility at Cornell University which can provide greatly improved X-ray beams due to the high electron-beam quality that is available from a linac, a phase 1 R&D program was launched, adressing critical challenges in the design. One of them being a full linac cryo-module, housing 6 superconducting cavities (operated at 1.8 K in cw mode), 7 HOM absorbers and 1 magnet/ BPM section. The final design will be presented and a report on the fabrication status that started in late 2012 will be given

WEPAC13

Achieving High Accuracy in Cornell's ERL Cavity Production

817

R.G. Eichhorn, B. Bullock, B. Clasby, J.J. Kaufman, B.M. Kilpatrick, S. Posen, 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

Funding: Supported by NSF award DMR-0807731
The phase 1 R&D program launched in preparation to building a 5 GeV Enery 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.

THPAC19

Temperature Dependence of Photoemission from Copper and Niobium

1184

J.R. Harris
CSU, Fort Collins, Colorado, USA
C.W. Bennett, M.D. Galt, A.D. Holmes, A. Kara, R. Swent
NPS, Monterey, California, USA
J.W. Lewellen
LANL, Los Alamos, New Mexico, USA
J. Sears
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: This work was funded by the Office of Naval Research and the High Energy Laser Joint Technology Office.
Photocathodes remain the principal electron sources for many particle accelerators. With the increasing interest in the use of superconducting radiofrequency electron guns, it is important to understand how operation at cryogenic temperatures affects the performance of photocathodes. Here we report measurements of the quantum efficiency of copper and niobium under illumination with 266 nm light at temperatures between 85K and 400K. The quantum efficiency of copper was found to vary strongly over this range, while there was only a minimal change in the quantum efficiency of niobium.

THPMA07

Cryomodule Performance of the Main Linac Prototype Cavity for Cornell's Energy Recovery Linac

1367

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

Funding: NSF Grants: NSF DMR-0807731 and NSF PHY-1002467
Energy Recovery Linacs (ERLs) require strong damping of higher-order modes in main linac cavities to avoid beam loss from beam break-up effects. In addition, the cavities need to have very high intrinsic quality factors to minimize the size of cryogenic plants in CW cavity operation. We present world record results for a fully equipped multicell cavity in a cryomodule, reaching intrinsic quality factors at operating accelerating field of Q₀(E =16.2 MV/m, 1.8~K) > 6.0\ee10 and Q₀(E =16.2 MV/m, 1.6~K) = 1.0\ee{11}, corresponding to a residual surface resistance of 1.1~nΩ.