A dished head and a wall part are integrally formed in one body by spinning,
using
a flat aluminum based material, and then a corrosion-proof protective coating is
formed on the whole surface by the Irridite process to complete the canister. The
combination of appropriate material selection and production process saves the
processing time (man-hour) needed for forming resonator canisters and its surface
treatment, improves the thermal conductivity, and consequently decreases individual
differences of the radio frequency loss in resonator canisters.