LINAC2014 - List of Authors (Hall, D.L.)

Paper	Title	Page
MOPP018	Nitrogen-Doped 9-Cell Cavity Performance in the Cornell Horizontal Test Cryomodule	88
	D. Gonnella, R.G. Eichhorn, F. Furuta, G.M. Ge, D.L. Hall, Y. He, G.H. Hoffstaetter, M. Liepe, T.I. O'Connel, S. Posen, P. Quigley, J. Sears, V. Veshcherevich Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA A. Grassellino, A. Romanenko Fermilab, Batavia, Illinois, USA
	Funding: U.S. Department of Energy Cornell has recently completed construction and qualification of a horizontal cryomodule capable of holding a 9-cell ILC cavity. A nitrogen-doped niobium 9-cell cavity was assembled into the Horizontal Test Cryomodule (HTC) with a high Q input coupler and tested. We report on results from this test of a nitrogen-doped cavity in cryomodule and discuss the effects of cool down rate and thermal cycling on the residual resistance of the cavity.

THPP017	Beam-Based HOM Studies of the Cornell Energy Recovery Linac 7-Cell SRF Cavity	869
	D.L. Hall, A.C. Bartnik, M.G. Billing, R.G. Eichhorn, G.H. Hoffstaetter, M. Liepe, C.E. Mayes, P. Quigley, V. Veshcherevich Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: NSF Grant DMR-0807731 The 1.3 GHz 7-cell SRF cavity for the Cornell ERL main linac is optimized for high beam current ERL operation with injected CW beam currents of 100 mA. Beam stability at 100 mA requires very strong damping of the Higher-Order-Modes (HOM) in the cavity by HOM beamline absorbers at the ends of the cavity. To verify the optimized design of the cavity and the HOM damping scheme, a prototype 7-cell main linac cavity was installed into the Cornell Horizontal Test Cryomodule (HTC), and inserted into the beamline of the Cornell ERL high current photo-injector. A beam-based method was then used to search for the presence of dangerous HOMs. Individual HOMs were excited using a charge-modulated beam, after which their effect upon an unmodulated beam was observed using a BPM. Data collected was used to calculate loaded Q of observed HOMs. Results show that it is very unlikely that HOMs will cause BBU in the Cornell ERL. In addition, measurements of the temperature rise of the HOM absorber rings during high current CW beam tests were consistent with simulations, indicating that the optimized main linac cavity is capable of operating at the specified current of 100mA in an ERL configuration.

THPP018	Sample Plate Studies Using a High Field TE Cavity With Thermometry Mapping System	873
	D.L. Hall, C.D. Burton, M. Liepe Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: NSF Career Grant PHY-0841213 A TE-Mode sample plate cavity capable of sustaining peak fields of >90 mT on the surface of a 10cm diameter sample plate has been developed and tested at Cornell. A thermometry mapping system composed of 40 Allen-Bradley resistors, mounted on the outside of the sample plate, is capable of measuring the surface resistance of the sample with a resolution of 1 nOhm and a spatial resolution of 0.5 cm. In this paper we present the design and expected performance of this high field TE cavity, and show data taken with a sample plate of niobium as well as results from tests qualifying the performance of the thermometry mapping system.

Paper

Title

Page

Nitrogen-Doped 9-Cell Cavity Performance in the Cornell Horizontal Test Cryomodule

88

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

Funding: U.S. Department of Energy
Cornell has recently completed construction and qualification of a horizontal cryomodule capable of holding a 9-cell ILC cavity. A nitrogen-doped niobium 9-cell cavity was assembled into the Horizontal Test Cryomodule (HTC) with a high Q input coupler and tested. We report on results from this test of a nitrogen-doped cavity in cryomodule and discuss the effects of cool down rate and thermal cycling on the residual resistance of the cavity.

THPP017

Beam-Based HOM Studies of the Cornell Energy Recovery Linac 7-Cell SRF Cavity

869

D.L. Hall, A.C. Bartnik, M.G. Billing, R.G. Eichhorn, G.H. Hoffstaetter, M. Liepe, C.E. Mayes, P. Quigley, V. Veshcherevich
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: NSF Grant DMR-0807731
The 1.3 GHz 7-cell SRF cavity for the Cornell ERL main linac is optimized for high beam current ERL operation with injected CW beam currents of 100 mA. Beam stability at 100 mA requires very strong damping of the Higher-Order-Modes (HOM) in the cavity by HOM beamline absorbers at the ends of the cavity. To verify the optimized design of the cavity and the HOM damping scheme, a prototype 7-cell main linac cavity was installed into the Cornell Horizontal Test Cryomodule (HTC), and inserted into the beamline of the Cornell ERL high current photo-injector. A beam-based method was then used to search for the presence of dangerous HOMs. Individual HOMs were excited using a charge-modulated beam, after which their effect upon an unmodulated beam was observed using a BPM. Data collected was used to calculate loaded Q of observed HOMs. Results show that it is very unlikely that HOMs will cause BBU in the Cornell ERL. In addition, measurements of the temperature rise of the HOM absorber rings during high current CW beam tests were consistent with simulations, indicating that the optimized main linac cavity is capable of operating at the specified current of 100mA in an ERL configuration.

THPP018

Sample Plate Studies Using a High Field TE Cavity With Thermometry Mapping System

873

D.L. Hall, C.D. Burton, M. Liepe
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: NSF Career Grant PHY-0841213
A TE-Mode sample plate cavity capable of sustaining peak fields of >90 mT on the surface of a 10cm diameter sample plate has been developed and tested at Cornell. A thermometry mapping system composed of 40 Allen-Bradley resistors, mounted on the outside of the sample plate, is capable of measuring the surface resistance of the sample with a resolution of 1 nOhm and a spatial resolution of 0.5 cm. In this paper we present the design and expected performance of this high field TE cavity, and show data taken with a sample plate of niobium as well as results from tests qualifying the performance of the thermometry mapping system.