SRF2015 - List of Authors (Hopper, C.S.)

Paper	Title	Page
WEBA05	Achieving High Peak Fields and Low Residual Resistance in Half-Wave Cavities	973
	Z.A. Conway, A. Barcikowski, G.L. Cherry, R.L. Fischer, S.M. Gerbick, C.S. Hopper, M. Kedzie, M.P. Kelly, S.H. Kim, S.W.T. MacDonald, B. Mustapha, P.N. Ostroumov, T. Reid ANL, Argonne, Illinois, USA
	Funding: Work supported by the U.S. Department of Energy Office of Science, Office of Nuclear Physics contract number DE-AC02-06CH11357, and the Office of High Energy Physics contract number DE-AC02-76CH03000. We have designed, fabricated and tested two new half-wave resonators following the successful development of a series of niobium superconducting quarter-wave cavities. The half-wave resonators are optimized for β = 0.11 ions, operate at 162.5 MHz and are intended to provide up to 2 MV effective voltage for particles with the optimal velocity. Testing of the first two half-wave resonators is complete with both reaching accelerating voltages greater than 3.5 MV with low-field residual resistances of 1.7 and 2.3 nΩ respectively. The intention of this paper is to provide insight into how Argonne achieves low-residual resistances and high surface fields in low-beta cavities by describing the cavity design, fabrication, processing and testing.
	Slides WEBA05 [2.927 MB]
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TUPB071	Development and Testing of a 325 MHz beta0 = 0.82 Single-Spoke Cavity	744
	C.S. Hopper, J.R. Delayen, H. Park ODU, Norfolk, Virginia, USA J.R. Delayen, H. Park JLab, Newport News, Virginia, USA
	A single-spoke cavity operating at 325 MHz with geometric beta of 0.82 has been developed and tested. Initial results* showed high levels of field emission which limited the achievable gradient. Several rounds of helium processing significantly improved the cavity performance. Here we discuss the development process and report on the improved results. *C.S. Hopper, HyeKyoung Park, and J.R. Delayen, “Cryogenic Testing of High-Velocity Spoke Cavities,” Proc. of the 27th Linear Accelerator Conference, Geneva, Switzerland, TUPP109, (2014).
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WEA2A01	High-Velocity Spoke Cavities	943
	C.S. Hopper ODU, Norfolk, Virginia, USA H. Park JLab, Newport News, Virginia, USA
	There are several current and recent projects which explore the feasibility of spoke-loaded cavities operating in the high-velocity region. Spoke cavities have a large number of geometric parameters which often influence multiple rf properties. Fabricating, handling, and processing these cavities presents some unique challenges, not unlike other TEM-class structures. This paper will summarize the current efforts toward the design, fabrication, and testing of spoke cavities with optimum beta greater than 0.8.
	Slides WEA2A01 [1.029 MB]
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Paper

Title

Page

Achieving High Peak Fields and Low Residual Resistance in Half-Wave Cavities

973

Z.A. Conway, A. Barcikowski, G.L. Cherry, R.L. Fischer, S.M. Gerbick, C.S. Hopper, M. Kedzie, M.P. Kelly, S.H. Kim, S.W.T. MacDonald, B. Mustapha, P.N. Ostroumov, T. Reid
ANL, Argonne, Illinois, USA

Funding: Work supported by the U.S. Department of Energy Office of Science, Office of Nuclear Physics contract number DE-AC02-06CH11357, and the Office of High Energy Physics contract number DE-AC02-76CH03000.
We have designed, fabricated and tested two new half-wave resonators following the successful development of a series of niobium superconducting quarter-wave cavities. The half-wave resonators are optimized for β = 0.11 ions, operate at 162.5 MHz and are intended to provide up to 2 MV effective voltage for particles with the optimal velocity. Testing of the first two half-wave resonators is complete with both reaching accelerating voltages greater than 3.5 MV with low-field residual resistances of 1.7 and 2.3 nΩ respectively. The intention of this paper is to provide insight into how Argonne achieves low-residual resistances and high surface fields in low-beta cavities by describing the cavity design, fabrication, processing and testing.

Slides WEBA05 [2.927 MB]

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TUPB071

Development and Testing of a 325 MHz beta0 = 0.82 Single-Spoke Cavity

744

C.S. Hopper, J.R. Delayen, H. Park
ODU, Norfolk, Virginia, USA
J.R. Delayen, H. Park
JLab, Newport News, Virginia, USA

A single-spoke cavity operating at 325 MHz with geometric beta of 0.82 has been developed and tested. Initial results* showed high levels of field emission which limited the achievable gradient. Several rounds of helium processing significantly improved the cavity performance. Here we discuss the development process and report on the improved results.
*C.S. Hopper, HyeKyoung Park, and J.R. Delayen, “Cryogenic Testing of High-Velocity Spoke Cavities,” Proc. of the 27th Linear Accelerator Conference, Geneva, Switzerland, TUPP109, (2014).

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WEA2A01

High-Velocity Spoke Cavities

943

C.S. Hopper
ODU, Norfolk, Virginia, USA
H. Park
JLab, Newport News, Virginia, USA

There are several current and recent projects which explore the feasibility of spoke-loaded cavities operating in the high-velocity region. Spoke cavities have a large number of geometric parameters which often influence multiple rf properties. Fabricating, handling, and processing these cavities presents some unique challenges, not unlike other TEM-class structures. This paper will summarize the current efforts toward the design, fabrication, and testing of spoke cavities with optimum beta greater than 0.8.

Slides WEA2A01 [1.029 MB]

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reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text, ※ RIS/RefMan, ※ EndNote (xml)