DEVELOPMENT, PRODUCTION AND TESTS OF PROTOTYPE SUPERCONDUCTING CAVITIES FOR THE HIGH BETA SECTION OF THE ISAC-II HEAVY ION ACCELERATOR AT TRIUMF

V. Zvyagintsevª¹, R.E. Laxdal¹, R. Dawson¹, K. Fong¹, A. Grasselino¹, P. Harmer¹, M. Marchetto¹, A.K. Mitra¹, T. Ries¹, B. Waraich¹, Q. Zheng¹, R. Edinger²

¹Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada

²Pavac Industries Inc., Richmond, Canada

Abstract

The medium beta section of the ISAC-II heavy ion superconducting linear accelerator, consisting of 20 cavities, has been in operation at TRIUMF since 2006. The high beta section of the accelerator, consisting of an additional twenty cavities, is currently under development and is scheduled for completion in 2009. The cavity is a superconducting bulk Niobium two-gap quarter-wave resonator for frequency 141 MHz, optimum β=0.11, providing, as a design goal, a voltage gain of V_a=1.08 MV at 7 W power dissipation. The inner conductor is equipped with a donut drift tube. The cavity has a double wall mechanical structure with liquid Helium inside. Two prototype cavities for the ISAC-II high beta section were developed at TRIUMF and produced by a Canadian company, PAVAC Industries of Richmond, B.C. The prototypes are equipped with a mechanical dissipator to damp detuning environmental mechanical vibrations. An inductive coupler, developed at TRIUMF, provides low power dissipations to the liquid helium system. Superconducting RF tests of both cavity prototypes show that we have achieved the required frequency and exceeded the design goal parameters. Response of the cavity to liquid helium pressure fluctuations, Lorentz force detuning and microphonic sensitivity with and without the damper was tested. RF design, prototype production details and cavity test results will be presented and discussed.

ª – corresponding author

Paper Slides

288