SRF2013 - List of Authors (Weissman, L.)

Paper	Title	Page
THP066	SARAF Phase-I HWR Coupler Cooling Design	1073
	J. Rodnizki, Y. Ben Aliz, I. Fishman, A. Grin, Z. Horvitz, B. Kaizer, L. Weissman Soreq NRC, Yavne, Israel
	The Soreq Applied Research Accelerator Facility (SARAF) design is based on a 40 MeV 5 mA light ions superconducting RF linac. Phase I of SARAF delivers up to 2 mA CW proton beam in an energy range of 1.5-4.5 MeV. The maximum beam power that we have reached is 4.5 kW. The warming of the SARAF linac RF couplers is currently the main limiting factor for reaching higher CW beam power. The coupler cooling configuration was optimized by increasing the cold window copper braid and adding a copper braid to the top end, using CST Multiphysics and ANSYS steady state and transient solvers. The study was conducted for the heat load generated by the surface currents of a matched 4 kW forward CW power, simulated by the CST MWS FD solver. Multipacting is a known potential heat source that overheats the coupler in the vicinity of the cold window. The coupler overheat phenomena was experimentally studied as a function of DC bias voltage, and it was found that a 900 V bias reduces significantly the heating rate. As a result we expect that the beam power can be significantly increased. The long overheat period implies that optimization of the cooling configuration is still needed.

Paper

Title

Page

SARAF Phase-I HWR Coupler Cooling Design

1073

J. Rodnizki, Y. Ben Aliz, I. Fishman, A. Grin, Z. Horvitz, B. Kaizer, L. Weissman
Soreq NRC, Yavne, Israel

The Soreq Applied Research Accelerator Facility (SARAF) design is based on a 40 MeV 5 mA light ions superconducting RF linac. Phase I of SARAF delivers up to 2 mA CW proton beam in an energy range of 1.5-4.5 MeV. The maximum beam power that we have reached is 4.5 kW. The warming of the SARAF linac RF couplers is currently the main limiting factor for reaching higher CW beam power. The coupler cooling configuration was optimized by increasing the cold window copper braid and adding a copper braid to the top end, using CST Multiphysics and ANSYS steady state and transient solvers. The study was conducted for the heat load generated by the surface currents of a matched 4 kW forward CW power, simulated by the CST MWS FD solver. Multipacting is a known potential heat source that overheats the coupler in the vicinity of the cold window. The coupler overheat phenomena was experimentally studied as a function of DC bias voltage, and it was found that a 900 V bias reduces significantly the heating rate. As a result we expect that the beam power can be significantly increased. The long overheat period implies that optimization of the cooling configuration is still needed.