SRF2013 - List of Authors (Kim, S.H.)

Paper

Title

Page

Development of Compact Cryomodules Housing HWRs for High-intensity SC CW Linacs

277

P.N. Ostroumov, Z.A. Conway, S.M. Gerbick, M. Kedzie, M.P. Kelly, S.H. Kim, S.V. Kutsaev, R.C. Murphy, B. Mustapha, T. Reid
ANL, Argonne, USA
D. Berkovits
Soreq NRC, Yavne, Israel
S. Nagaitsev
Fermilab, Batavia, USA

Funding: This work was supported by the U.S. Department of Energy, under Contracts No. DE-AC02-06CH11357, DE-AC02-76CH03000 and ANL WFO No. 85Y47.
Acceleration of high-intensity light-ion beams immediately after an RFQ requires a compact accelerating and focusing lattice with a high packing factor. We have developed a cryomodule which satisfies this requirement with eight accelerating-focusing periods for Project X at FNAL. Each focusing period consist of a 162.5-MHz SC HWR, a SC solenoid and a beam position monitor. The highly optimized EM parameters of the cavity were achieved by using double conical, hour glass like, inner and outer conductors. This design is also favorable for the beam dynamics because the short focusing periods which helps to better control the beam quality. All sub-systems of the cryomodule, except the vacuum-vessel, are in advanced stages of prototyping and testing. A similar concept has been developed for the design of several cryomodules for a 20 MeV/u proton/deuteron 200 kW linac at SNRC. These cryomodules house two types of 176 MHz half-wave resonators and require only modest modifications for the application. This paper will discuss the status of the FNAL cryomodule design and sub-system fabrication and its impact on future HWR cryomodule such as the SNRC project.

THIOC01

Low Beta Cavity Development for an ATLAS Intensity Upgrade

850

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

The set of seven new 72 MHz quarter wave SC (QWR) cavities has been completed and is being installed in the ATLAS heavy-ion accelerator at Argonne. The aim is to provide at least 17.5 MV accelerating potential with large acceptance and minimal beam losses for high intensity ion beams. The cavity electromagnetic design uses optimizations not used before with QWR including a large taper on both the inner and outer conductors in order to reduce surface fields and make efficient use of space along the beam line. Electropolishing (EP) on the finished cavities with integral helium jacket and no demountable RF joints has been performed, and is the first for any low beta SC cavity. This type of EP, adapted from Argonne systems for the linear collider effort, appears to have a large benefit in terms of the average quench field which range between 103-165 mT for five QWR tested to date. Cavity residual resistances at the proposed operating point of ~70 mT are low, clustering close to a value of ~2nOhm. Additional technical details including the almost exclusive use of wire EDM for niobium fabrication and a new CW 4 kW RF power coupler are presented.

Slides THIOC01 [10.152 MB]

Paper	Title	Page
MOP066	Development of Compact Cryomodules Housing HWRs for High-intensity SC CW Linacs	277
	P.N. Ostroumov, Z.A. Conway, S.M. Gerbick, M. Kedzie, M.P. Kelly, S.H. Kim, S.V. Kutsaev, R.C. Murphy, B. Mustapha, T. Reid ANL, Argonne, USA D. Berkovits Soreq NRC, Yavne, Israel S. Nagaitsev Fermilab, Batavia, USA
	Funding: This work was supported by the U.S. Department of Energy, under Contracts No. DE-AC02-06CH11357, DE-AC02-76CH03000 and ANL WFO No. 85Y47. Acceleration of high-intensity light-ion beams immediately after an RFQ requires a compact accelerating and focusing lattice with a high packing factor. We have developed a cryomodule which satisfies this requirement with eight accelerating-focusing periods for Project X at FNAL. Each focusing period consist of a 162.5-MHz SC HWR, a SC solenoid and a beam position monitor. The highly optimized EM parameters of the cavity were achieved by using double conical, hour glass like, inner and outer conductors. This design is also favorable for the beam dynamics because the short focusing periods which helps to better control the beam quality. All sub-systems of the cryomodule, except the vacuum-vessel, are in advanced stages of prototyping and testing. A similar concept has been developed for the design of several cryomodules for a 20 MeV/u proton/deuteron 200 kW linac at SNRC. These cryomodules house two types of 176 MHz half-wave resonators and require only modest modifications for the application. This paper will discuss the status of the FNAL cryomodule design and sub-system fabrication and its impact on future HWR cryomodule such as the SNRC project.

THIOC01	Low Beta Cavity Development for an ATLAS Intensity Upgrade	850
	M.P. Kelly, Z.A. Conway, S.M. Gerbick, M. Kedzie, S.H. Kim, R.C. Murphy, B. Mustapha, P.N. Ostroumov, T. Reid ANL, Argonne, USA
	The set of seven new 72 MHz quarter wave SC (QWR) cavities has been completed and is being installed in the ATLAS heavy-ion accelerator at Argonne. The aim is to provide at least 17.5 MV accelerating potential with large acceptance and minimal beam losses for high intensity ion beams. The cavity electromagnetic design uses optimizations not used before with QWR including a large taper on both the inner and outer conductors in order to reduce surface fields and make efficient use of space along the beam line. Electropolishing (EP) on the finished cavities with integral helium jacket and no demountable RF joints has been performed, and is the first for any low beta SC cavity. This type of EP, adapted from Argonne systems for the linear collider effort, appears to have a large benefit in terms of the average quench field which range between 103-165 mT for five QWR tested to date. Cavity residual resistances at the proposed operating point of ~70 mT are low, clustering close to a value of ~2nOhm. Additional technical details including the almost exclusive use of wire EDM for niobium fabrication and a new CW 4 kW RF power coupler are presented.
	Slides THIOC01 [10.152 MB]