SRF2011 - List of Authors (Conway, Z.A.)

Paper

Title

Page

β = 0.285 Half-Wave Resonator for FRIB

132

P.N. Ostroumov, Z.A. Conway, R.L. Fischer, S.M. Gerbick, M.P. Kelly, A. Kolomiets, B. Mustapha, A. Ortega Bergado
ANL, Argonne, USA

Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357and WFO 85Y64 Supported by Michigan State University
We have developed an optimized electromagnetic and mechanical design of a 322 MHz half-wave resonator (HWR) suitable for acceleration of ions in the post-stripper section of the Facility for Rare Isotope Beams (FRIB). The cavity design is based on recent advances in SRF technology for TEM-class structures being developed at ANL. Highly optimized EM parameters were achieved using an ”hourglass” cavity shape for the HWR. This new design will be processed with a new HWR horizontal electropolishing system after all mechanical work on the cavity including the welding of the helium vessel is complete. Recently, this procedure was successfully tested on a quarter wave resonator developed for the ATLAS Upgrade which achieved peak surface fields of 70 MV/m and 10⁵ mT. Following these results we propose to operate the HWR with a 2.6 MV accelerating voltage per cavity at the optimal ion velocity of β = 0.285. Fabrication of the cavity can be started immediately as soon as funding is available.

MOPO044

Electromagnetic Design Optimization of a Half-Wave Resonator

192

B. Mustapha, Z.A. Conway, A. Kolomiets, P.N. Ostroumov
ANL, Argonne, USA

Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357and WFO 85Y64 Supported by Michigan State University
The optimization procedure developed for the electromagnetic (EM) design of the ATLAS Upgrade quarter-wave resonator (QWR) [1] has now been successfully tested. The prototype QWR achieved record peak surface fields of 70 MV/m and 10⁵ mT and is capable of providing 4.4 MV, far exceeding the design voltage of 2.5 MV. We have developed and applied a similar procedure for the EM design of a 322 MHz - β ~ 0.29 half-wave resonator (HWR) for the medium energy section of the FRIB driver linac. The optimization path and the final results will be presented and discussed. The choice of aperture and its effect on the EM design parameters will be discussed. A comparison between equivalent half-wave and single-spoke resonators will also be presented. The transition from the electromagnetic model in MWS to the engineering model in Inventor was carefully studied as it may affect both the EM design parameters and the cavity fabrication.
* “Electromagnetic Optimization of a Quarter-Wave Resonator” B. Mustapha and P. Ostroumov, Proceedings of Linac-10, Tsukuba, Japan.

THIOB04

SRF Advances for ATLAS and other β<1 Applications

680

M.P. Kelly, Z.A. Conway, S.M. Gerbick, M. Kedzie, R.C. Murphy, B. Mustapha, P.N. Ostroumov, T. Reid
ANL, Argonne, USA

The guiding principle for the design of the new 72 MHz quarter wave SC cavities at Argonne was to provide the maximum possible accelerating gradient along the linac with large acceptance and minimal beam losses. Cavities will be installed into ATLAS in 2012 as the beam intensity upgrade, but are also intended for the next generation of ion linacs to be used in basic and applied science and technology. State-of-the-art cavity designs and fabrication techniques developed at ANL have been applied to the construction of the first prototype. Tests of the prototype 72 MHz QWR demonstrate the highest performance achieved to date for this class of cavity designed to cover the velocity range 0.06<β<0.12. The cavity has very low RF losses and the highest accelerating gradients ever achieved for any quarter-wave structure. Indeed, the accelerating voltage of 4.3 MV is roughly four times higher than that reported for the best SC cavities in this velocity range currently in operation at any facility worldwide. Also, this demonstrated 4.3 MV accelerating voltage substantially exceeds the 2.5 MV design voltage.

Slides THIOB04 [3.571 MB]

FRIOA02

Innovative Tuner Designs For Low Beta SRF Cavities

943

Z.A. Conway, M.P. Kelly, P.N. Ostroumov
ANL, Argonne, USA
K.W. Shepard
TechSource, Los Alamos, NM, USA

This presentation will give an overview of innovative low-beta (0.05 < beta < 0.6) cavity frequency tuners for heavy-ion accelerators. These cavities typically operate with microphonic induced frequency perturbations which are a significant fraction of the loaded bandwidth. If uncompensated these frequency variations may unnecessarily increase the RF power required to stabilize the phase and amplitude of the cavity RF fields. Several tuner designs with operating details will be reviewed.

Slides FRIOA02 [3.112 MB]

Paper	Title	Page
MOPO026	β = 0.285 Half-Wave Resonator for FRIB	132
	P.N. Ostroumov, Z.A. Conway, R.L. Fischer, S.M. Gerbick, M.P. Kelly, A. Kolomiets, B. Mustapha, A. Ortega Bergado ANL, Argonne, USA
	Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357and WFO 85Y64 Supported by Michigan State University We have developed an optimized electromagnetic and mechanical design of a 322 MHz half-wave resonator (HWR) suitable for acceleration of ions in the post-stripper section of the Facility for Rare Isotope Beams (FRIB). The cavity design is based on recent advances in SRF technology for TEM-class structures being developed at ANL. Highly optimized EM parameters were achieved using an ”hourglass” cavity shape for the HWR. This new design will be processed with a new HWR horizontal electropolishing system after all mechanical work on the cavity including the welding of the helium vessel is complete. Recently, this procedure was successfully tested on a quarter wave resonator developed for the ATLAS Upgrade which achieved peak surface fields of 70 MV/m and 10⁵ mT. Following these results we propose to operate the HWR with a 2.6 MV accelerating voltage per cavity at the optimal ion velocity of β = 0.285. Fabrication of the cavity can be started immediately as soon as funding is available.

MOPO044	Electromagnetic Design Optimization of a Half-Wave Resonator	192
	B. Mustapha, Z.A. Conway, A. Kolomiets, P.N. Ostroumov ANL, Argonne, USA
	Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357and WFO 85Y64 Supported by Michigan State University The optimization procedure developed for the electromagnetic (EM) design of the ATLAS Upgrade quarter-wave resonator (QWR) [1] has now been successfully tested. The prototype QWR achieved record peak surface fields of 70 MV/m and 10⁵ mT and is capable of providing 4.4 MV, far exceeding the design voltage of 2.5 MV. We have developed and applied a similar procedure for the EM design of a 322 MHz - β ~ 0.29 half-wave resonator (HWR) for the medium energy section of the FRIB driver linac. The optimization path and the final results will be presented and discussed. The choice of aperture and its effect on the EM design parameters will be discussed. A comparison between equivalent half-wave and single-spoke resonators will also be presented. The transition from the electromagnetic model in MWS to the engineering model in Inventor was carefully studied as it may affect both the EM design parameters and the cavity fabrication. * “Electromagnetic Optimization of a Quarter-Wave Resonator” B. Mustapha and P. Ostroumov, Proceedings of Linac-10, Tsukuba, Japan.

THIOB04	SRF Advances for ATLAS and other β<1 Applications	680
	M.P. Kelly, Z.A. Conway, S.M. Gerbick, M. Kedzie, R.C. Murphy, B. Mustapha, P.N. Ostroumov, T. Reid ANL, Argonne, USA
	The guiding principle for the design of the new 72 MHz quarter wave SC cavities at Argonne was to provide the maximum possible accelerating gradient along the linac with large acceptance and minimal beam losses. Cavities will be installed into ATLAS in 2012 as the beam intensity upgrade, but are also intended for the next generation of ion linacs to be used in basic and applied science and technology. State-of-the-art cavity designs and fabrication techniques developed at ANL have been applied to the construction of the first prototype. Tests of the prototype 72 MHz QWR demonstrate the highest performance achieved to date for this class of cavity designed to cover the velocity range 0.06<β<0.12. The cavity has very low RF losses and the highest accelerating gradients ever achieved for any quarter-wave structure. Indeed, the accelerating voltage of 4.3 MV is roughly four times higher than that reported for the best SC cavities in this velocity range currently in operation at any facility worldwide. Also, this demonstrated 4.3 MV accelerating voltage substantially exceeds the 2.5 MV design voltage.
	Slides THIOB04 [3.571 MB]

FRIOA02	Innovative Tuner Designs For Low Beta SRF Cavities	943
	Z.A. Conway, M.P. Kelly, P.N. Ostroumov ANL, Argonne, USA K.W. Shepard TechSource, Los Alamos, NM, USA
	This presentation will give an overview of innovative low-beta (0.05 < beta < 0.6) cavity frequency tuners for heavy-ion accelerators. These cavities typically operate with microphonic induced frequency perturbations which are a significant fraction of the loaded bandwidth. If uncompensated these frequency variations may unnecessarily increase the RF power required to stabilize the phase and amplitude of the cavity RF fields. Several tuner designs with operating details will be reviewed.
	Slides FRIOA02 [3.112 MB]