LINAC2014 - List of Authors (Parma, V.)

Paper

Title

Page

Actively Cooled RF Power Coupler : Theoretical and Experimental Studies

111

R. Bonomi, V. Parma
CERN, Geneva, Switzerland

In cryostats for Super-conducting Radio Frequency Cavities, the heat loads introduced by the high-power RF couplers represent an important fraction of the overall static thermal budget. Working at low operating temperature benefits from a reduced surface resistance (low dynamic losses) but is penalized by the high refrigeration cost. The external conductor of RF coaxial couplers provides a direct conduction path from ambient to cryogenic temperature plus is heated by resistive power deposition. Heat interception is therefore essential to contain heat in-leaks: a double-walled external conductor with a properly designed gas cooling effectively reduces heat loads to the cold bath by 1 order of magnitude. This paper presents the thermal design of the RF power coupler of the Superconducting Proton Linac (SPL) at CERN, featuring a helium vapour cooling between 4.5 K and ambient temperature. Numerical models, which can be used as design tools for other applications, have been developed to assess efficiency and thermal performance. A full-size mock-up cooled by nitrogen has been built for experimental validation. Comparison between calculations and measurements is presented and discussed.

THIOA03

Status of the HIE-ISOLDE Linac

795

W. Venturini Delsolaro, L. Alberty, L. Arnaudon, K. Artoos, J. Bauche, A.P. Bernardes, J.A. Bousquet, E. Bravin, S. Calatroni, E.D. Cantero, O. Capatina, N. Delruelle, D. Duarte Ramos, M. Elias, F. Formenti, M.A. Fraser, J. Gayde, S. Giron, N.M. Jecklin, Y. Kadi, G. Kautzmann, Y. Leclercq, P. Maesen, V. Mertens, E. Montesinos, V. Parma, G.J. Rosaz, K.M. Schirm, E. Siesling, D. Smekens, A. Sublet, M. Therasse, D. Valuch, G. Vandoni, E. Vergara Fernandez, D. Voulot, L.R. Williams, P. Zhang
CERN, Geneva, Switzerland

The HIE-ISOLDE project aims at increasing the energy of the radioactive beams (RIB) of REX-ISOLDE from the present 3 MeV/u up to 10 MeV/u for A/q up to 4.5. This will be accomplished by means of a new superconducting linac, based on independently phased quarter wave resonators using the Nb sputtering on copper technology, and working at 101.28 MHz. The focusing elements are superconducting solenoids providing 13.5 T2m field integral. These active elements are contained in a common vacuum cryostat. The presentation will cover the status of advancement of the HIE-ISOLDE linac technical systems. The performance of the superconducting elements will be presented, together with the assembly work of the cryomodule in clean room and the planned qualification tests in the horizontal test facility at CERN

Slides THIOA03 [24.692 MB]

Paper	Title	Page
MOPP026	Actively Cooled RF Power Coupler : Theoretical and Experimental Studies	111
	R. Bonomi, V. Parma CERN, Geneva, Switzerland
	In cryostats for Super-conducting Radio Frequency Cavities, the heat loads introduced by the high-power RF couplers represent an important fraction of the overall static thermal budget. Working at low operating temperature benefits from a reduced surface resistance (low dynamic losses) but is penalized by the high refrigeration cost. The external conductor of RF coaxial couplers provides a direct conduction path from ambient to cryogenic temperature plus is heated by resistive power deposition. Heat interception is therefore essential to contain heat in-leaks: a double-walled external conductor with a properly designed gas cooling effectively reduces heat loads to the cold bath by 1 order of magnitude. This paper presents the thermal design of the RF power coupler of the Superconducting Proton Linac (SPL) at CERN, featuring a helium vapour cooling between 4.5 K and ambient temperature. Numerical models, which can be used as design tools for other applications, have been developed to assess efficiency and thermal performance. A full-size mock-up cooled by nitrogen has been built for experimental validation. Comparison between calculations and measurements is presented and discussed.

THIOA03	Status of the HIE-ISOLDE Linac	795
	W. Venturini Delsolaro, L. Alberty, L. Arnaudon, K. Artoos, J. Bauche, A.P. Bernardes, J.A. Bousquet, E. Bravin, S. Calatroni, E.D. Cantero, O. Capatina, N. Delruelle, D. Duarte Ramos, M. Elias, F. Formenti, M.A. Fraser, J. Gayde, S. Giron, N.M. Jecklin, Y. Kadi, G. Kautzmann, Y. Leclercq, P. Maesen, V. Mertens, E. Montesinos, V. Parma, G.J. Rosaz, K.M. Schirm, E. Siesling, D. Smekens, A. Sublet, M. Therasse, D. Valuch, G. Vandoni, E. Vergara Fernandez, D. Voulot, L.R. Williams, P. Zhang CERN, Geneva, Switzerland
	The HIE-ISOLDE project aims at increasing the energy of the radioactive beams (RIB) of REX-ISOLDE from the present 3 MeV/u up to 10 MeV/u for A/q up to 4.5. This will be accomplished by means of a new superconducting linac, based on independently phased quarter wave resonators using the Nb sputtering on copper technology, and working at 101.28 MHz. The focusing elements are superconducting solenoids providing 13.5 T2m field integral. These active elements are contained in a common vacuum cryostat. The presentation will cover the status of advancement of the HIE-ISOLDE linac technical systems. The performance of the superconducting elements will be presented, together with the assembly work of the cryomodule in clean room and the planned qualification tests in the horizontal test facility at CERN
	Slides THIOA03 [24.692 MB]