Plans are underway to develop a medium beta (0.61) and a high beta (0.81) cryomodule for the super-conducting portion of the Spallation Neutron Source. This paper describes the design of these cryomodules that provide a significant portion of the total ac celeration to the proton beam. The design minimizes the effect of losses on cavity performance by preserving cavity cleanliness, maintaining high vacuum and shielding the cavity from the earth’s magnetic field. A modal analysis was performed to maintain r esonance by minimizing cavity microphonics and provide cavity tuning. The cryomodule design optimizes the cryostat heat load to the refrigerator on the primary (2 K), secondary (5 K) and shield (50 K) circuits and facilitates production of multiple module s (thirty-two maximum) at a reasonable cost. The paper describes the two types of cavities, the helium vessel, the tuner, the magnetic shields, the thermal shield, the power couplers, the space frame, the vacuum tank and the end cans that make up the medi um and high beta cryomodules.

This work was supported by U.S. DOE under contract DE-AC05-00OR22725.

Authors: W. Schneider, E. Daly, J. Hogan, T. Hiatt, P. Kneisel, D. Machie, K. Matsumoto, R. Mitchell, J. Preble, C. Rode, T. Whitlatch, K. Wilson, M. Wiseman

Abstract submitted to PAC 2001, Chicago, IL, June 18-24, 2001

Updated March 28, 2001

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