ACCELERATION SYSTEM FOK 'THE KCNP RING CYCLOTRON

Abstract-~ A variable frequency Hl,,l mode single-gap cavity has been made for the RCNP ring cyclotron. The fre-quency range is 22 to 33 MHz. Radially increasing voltage distributions of the acceleration system pro-duce beam phase compression ratio of about 3. The cavity was excited up to 270 kV at 33 MHz in a prelimi-nary test. A 20 inch cryopump evacuated the aluminium cavity chamber dovln to 1 x lo- ' Tbrr