IPAC2013 - List of Authors (Sears, J.)

Paper	Title	Page
WEPWO059	Cornell's HOM Beamline Absorbers	2441
	R. Eichhorn, J.V. Conway, Y. He, G.H. Hoffstaetter, M. Liepe, T.I. O'Connell, P. Quigley, J. Sears, V.D. Shemelin, N.R.A. Valles CLASSE, Ithaca, New York, USA
	The proposed energy recovery linac at Cornell aims for high beam currents and short bunch lengths, the combination of which requires efficient damping of the higher order modes (HOMs) being present in the superconducting cavities. Numerical simulations show that the expected HOM power could be as high as 200 W per cavity with frequencies ranging to 40 GHz. Consequently, a beam line absorber approach was chosen. We will review the design, report on first results from a prototype and discuss further improvements.

WEPWO060	The CW Linac Cryo-module for Cornell’s ERL	2444
	R. Eichhorn, Y. He, G.H. Hoffstaetter, M. Liepe, T.I. O'Connell, P. Quigley, D.M. Sabol, J. Sears, E.N. Smith, V. Veshcherevich CLASSE, Ithaca, New York, USA
	Cornell University has proposed an energy-recovery linac (ERL) based synchrotron-light facility which can provide greatly improved X-ray beams due to the high electron-beam quality that is available from a linac. As part of the phase 1 R&D program, critical challenges in the design were addressed, one of them being a full linac cryo-module. It houses 6 superconducting cavities- operated at 1.8 K in cw mode- HOM absorbers and a magnet/ BPM section. We will present the design being finalized recently and report on the fabrication status that started in late 2012.

WEPWO061	Readiness for the Cornell ERL	2447
	G.H. Hoffstaetter, A.C. Bartnik, I.V. Bazarov, D.H. Bilderback, M.G. Billing, J.D. Brock, J.A. Crittenden, L. Cultrera, D.S. Dale, J. Dobbins, B.M. Dunham, R.D. Ehrlich, M. P. Ehrlichman, R. Eichhorn, K. Finkelstein, E. Fontes, M.J. Forster, S.J. Full, F. Furuta, D. Gonnella, S.W. Gray, S.M. Gruner, C.M. Gulliford, D.L. Hartill, Y. He, R.G. Helmke, K.M.V. Ho, R.P.K. Kaplan, S.S. Karkare, V.O. Kostroun, H. Lee, Y. Li, M. Liepe, X. Liu, J.M. Maxson, C.E. Mayes, A.A. Mikhailichenko, H. Padamsee, J.R. Patterson, S.B. Peck, S. Posen, P. Quigley, P. Revesz, D.H. Rice, D. Sagan, J. Sears, V.D. Shemelin, D.M. Smilgies, E.N. Smith, K.W. Smolenski, A.B. Temnykh, M. Tigner, N.R.A. Valles, V. Veshcherevich, A.R. Woll, Y. Xie, Z. Zhao CLASSE, Ithaca, New York, USA
	Funding: Supported by NSF award DMR-0807731 and NY State Energy-Recovery Linacs (ERLs) are proposed as drivers for hard x-ray sources because of their ability to produce electron bunches with small, flexible cross sections and short lengths at high repetition rates. Cornell University has pioneered the design and hardware for ERL lightsources. This preparatory research for ERL-lightsource construction will be discussed. Important milestones have been achieved in Cornell's prototype ERL injector, including the production of a prototype SRF cavity that exceeds design specifications, the regular production of long-lived and low emittance cathodes, the acceleration of ultra-low emittance bunches, and the world-record of 65 mA current from a photoemission DC gun. We believe that demonstration of the practical feasibility of these technologies have progressed sufficiently to allow the construction of an ERL-based lightsource like that described in [erl.chess.cornell.edu/PDDR].

WEPWO066	Frequency Control in the Cornell-ERL Main-Linac Cavity Production	2453
	V.D. Shemelin, B. Bullock, P.R. Carriere, B. Clasby, R. Eichhorn, B. Elmore, J.J. Kaufman, J. Sears CLASSE, Ithaca, New York, USA
	Funding: NSF award DMR-0807731 Cavity fabrication can be broken down into three main stages: deep-drawing cups, welding the cups in pairs to obtain “dumbbells” and end groups, and, finally, welding the obtained components into a completed cavity. Frequency measurements and precise machining were implemented after the second stage. A custom RF fixture and data acquisition system were used for this purpose. The system comprised of a mechanical press with RF contacts, a network analyzer, a load cell and custom LabVIEW and MATLAB scripts. To extract the individual frequencies of the cups from these measurements, algorithm of calculations was developed. Corrections for the ambient environment were also incorporated into the measurement protocol. Two 7-cell 1.3 GHz cavities were produced with high field flatness immediately after fabrication.

WEPWO068	Cornell ERL Main Linac 7-cell Cavity Performance in Horizontal Test Cryomodule Qualifications	2459
	N.R.A. Valles, R. Eichhorn, F. Furuta, G.M. Ge, D. Gonnella, Y. He, K.M.V. Ho, G.H. Hoffstaetter, M. Liepe, T.I. O'Connell, S. Posen, P. Quigley, J. Sears, V. Veshcherevich CLASSE, Ithaca, New York, USA
	Funding: NSF DMR-0807731 Cornell has recently ﬁnished producing and testing the ﬁrst prototype 7-cell main linac cavity for the Cornell Energy Recovery Linac, and completed the prototype cavity qualification program. This paper presents quality factor results from the horizontal test cryomodule (HTC) measurements, from the HTC-1 through HTC-3 experiments, reaching Q's up to 6 x 10¹⁰ at 1.6 K. We investigate the effect of thermal cycling on cavity quality factor and show that high quality factors can be preserved from initial mounting to fully outfitting the cavity with side-mounted input coupler and beam line absorbers. We also discuss the production of six additional main-linac cavities as we progress toward constructing a full 6-cavity cryomodule.

Paper

Title

Page

Cornell's HOM Beamline Absorbers

2441

R. Eichhorn, J.V. Conway, Y. He, G.H. Hoffstaetter, M. Liepe, T.I. O'Connell, P. Quigley, J. Sears, V.D. Shemelin, N.R.A. Valles
CLASSE, Ithaca, New York, USA

The proposed energy recovery linac at Cornell aims for high beam currents and short bunch lengths, the combination of which requires efficient damping of the higher order modes (HOMs) being present in the superconducting cavities. Numerical simulations show that the expected HOM power could be as high as 200 W per cavity with frequencies ranging to 40 GHz. Consequently, a beam line absorber approach was chosen. We will review the design, report on first results from a prototype and discuss further improvements.

WEPWO060

The CW Linac Cryo-module for Cornell’s ERL

2444

R. Eichhorn, Y. He, G.H. Hoffstaetter, M. Liepe, T.I. O'Connell, P. Quigley, D.M. Sabol, J. Sears, E.N. Smith, V. Veshcherevich
CLASSE, Ithaca, New York, USA

Cornell University has proposed an energy-recovery linac (ERL) based synchrotron-light facility which can provide greatly improved X-ray beams due to the high electron-beam quality that is available from a linac. As part of the phase 1 R&D program, critical challenges in the design were addressed, one of them being a full linac cryo-module. It houses 6 superconducting cavities- operated at 1.8 K in cw mode- HOM absorbers and a magnet/ BPM section. We will present the design being finalized recently and report on the fabrication status that started in late 2012.

WEPWO061

Readiness for the Cornell ERL

2447

G.H. Hoffstaetter, A.C. Bartnik, I.V. Bazarov, D.H. Bilderback, M.G. Billing, J.D. Brock, J.A. Crittenden, L. Cultrera, D.S. Dale, J. Dobbins, B.M. Dunham, R.D. Ehrlich, M. P. Ehrlichman, R. Eichhorn, K. Finkelstein, E. Fontes, M.J. Forster, S.J. Full, F. Furuta, D. Gonnella, S.W. Gray, S.M. Gruner, C.M. Gulliford, D.L. Hartill, Y. He, R.G. Helmke, K.M.V. Ho, R.P.K. Kaplan, S.S. Karkare, V.O. Kostroun, H. Lee, Y. Li, M. Liepe, X. Liu, J.M. Maxson, C.E. Mayes, A.A. Mikhailichenko, H. Padamsee, J.R. Patterson, S.B. Peck, S. Posen, P. Quigley, P. Revesz, D.H. Rice, D. Sagan, J. Sears, V.D. Shemelin, D.M. Smilgies, E.N. Smith, K.W. Smolenski, A.B. Temnykh, M. Tigner, N.R.A. Valles, V. Veshcherevich, A.R. Woll, Y. Xie, Z. Zhao
CLASSE, Ithaca, New York, USA

Funding: Supported by NSF award DMR-0807731 and NY State
Energy-Recovery Linacs (ERLs) are proposed as drivers for hard x-ray sources because of their ability to produce electron bunches with small, flexible cross sections and short lengths at high repetition rates. Cornell University has pioneered the design and hardware for ERL lightsources. This preparatory research for ERL-lightsource construction will be discussed. Important milestones have been achieved in Cornell's prototype ERL injector, including the production of a prototype SRF cavity that exceeds design specifications, the regular production of long-lived and low emittance cathodes, the acceleration of ultra-low emittance bunches, and the world-record of 65 mA current from a photoemission DC gun. We believe that demonstration of the practical feasibility of these technologies have progressed sufficiently to allow the construction of an ERL-based lightsource like that described in [erl.chess.cornell.edu/PDDR].

WEPWO066

Frequency Control in the Cornell-ERL Main-Linac Cavity Production

2453

V.D. Shemelin, B. Bullock, P.R. Carriere, B. Clasby, R. Eichhorn, B. Elmore, J.J. Kaufman, J. Sears
CLASSE, Ithaca, New York, USA

Funding: NSF award DMR-0807731
Cavity fabrication can be broken down into three main stages: deep-drawing cups, welding the cups in pairs to obtain “dumbbells” and end groups, and, finally, welding the obtained components into a completed cavity. Frequency measurements and precise machining were implemented after the second stage. A custom RF fixture and data acquisition system were used for this purpose. The system comprised of a mechanical press with RF contacts, a network analyzer, a load cell and custom LabVIEW and MATLAB scripts. To extract the individual frequencies of the cups from these measurements, algorithm of calculations was developed. Corrections for the ambient environment were also incorporated into the measurement protocol. Two 7-cell 1.3 GHz cavities were produced with high field flatness immediately after fabrication.

WEPWO068

Cornell ERL Main Linac 7-cell Cavity Performance in Horizontal Test Cryomodule Qualifications

2459

N.R.A. Valles, R. Eichhorn, F. Furuta, G.M. Ge, D. Gonnella, Y. He, K.M.V. Ho, G.H. Hoffstaetter, M. Liepe, T.I. O'Connell, S. Posen, P. Quigley, J. Sears, V. Veshcherevich
CLASSE, Ithaca, New York, USA

Funding: NSF DMR-0807731
Cornell has recently ﬁnished producing and testing the ﬁrst prototype 7-cell main linac cavity for the Cornell Energy Recovery Linac, and completed the prototype cavity qualification program. This paper presents quality factor results from the horizontal test cryomodule (HTC) measurements, from the HTC-1 through HTC-3 experiments, reaching Q's up to 6 x 10¹⁰ at 1.6 K. We investigate the effect of thermal cycling on cavity quality factor and show that high quality factors can be preserved from initial mounting to fully outfitting the cavity with side-mounted input coupler and beam line absorbers. We also discuss the production of six additional main-linac cavities as we progress toward constructing a full 6-cavity cryomodule.