[en] It was decided to fabricate one RF Cavity with improved design, to be kept ready as a spare one for Booster/ lndus-1, in RRCAT, Indore. Copper-Stainless-Steel Capacitor discs, made by explosion-bonding, were chosen for use in this RF Cavity, and these discs were designed and manufactured by Industrial Accelerator Section, RRCAT. It was mandatory to check for the vacuum compatibility of these discs, prior to the final assembly. For this purpose, one test-chamber, as to contain the disc inside, was fabricated by Industrial Accelerator Section, RRCAT. This chamber was first tested and confirmed for its own vacuum compatibility. Afterwards the chamber was fitted inside with the Capacitor disc, and the whole set-up was tested for the vacuum compatibility. The test was successful, proving that the explosion bonded Capacitor disc was suitable to be used in RF Cavity for Indus-1 Booster. This paper describes the details of the tests - assembly, leak-checking, baking, pumping, pressure-rise tests and the results - ultimate vacuum achieved and the Residual-Gas-Analysis. (author)