Design of vacuum vessel for LB650 cryomodule

LB650 cryomodule is under design at RRCAT for upcoming spallation neutron source. LB650 cryomodule is ∼5.25 m long and houses four numbers of beta 0.61 650MHz SCRF cavities. Vacuum vessel of LB650 cryomodule provides insulating vacuum and structural support to cold mass comprising of SCRF cavities, thermal shield, support system, internal piping etc. LB650 MHz cryomodule vacuum vessel comprises of vessel shell, two numbers of end flanges, tuner ports, coupler ports, instrumentation and transport access ports and covers, strong back support posts and covers, relief port, side extension cover, top port, top hat and top hat cover. Analysis of vessel shell thickness for both internal and external pressure, calculations for flanges & covers, reinforcement requirements for openings, large openings of shell, and reinforcement for multiple openings on flat head and out of roundness calculations have been carried out. Vacuum vessel for LB650 cryomodule has been designed and engineering note has been prepared as per ASME Boiler and Pressure vessel code, Section VIII, Div. 1. (author)