VACUUM-SYSTEM OF HEAVY-ION ISOCHRONOUS CYCLOTRON U-400M

A new heavy ion isochronous cyclotron U-400M has been built at flerov Laboratory of Nuclear Reactions. Its vacuum chamber volume is 35 m(3) and its internal surface area is 375 m(2). The total gas flow is appro ximately 11 Pa s(-1). The pumping out is performed by six diffusion oi l pumps having liquid-nitrogen-cooled traps. The total pumping-out spe ed of the pumps is 24,000ls(-1) for air and 100,000ls(-1) for gases co ndensed at liquid nitrogen temperature. The pressure in the cyclotron vacuum chamber is 2 x 10(-5) pa and in the acceleration mode it is 10( -4) Pa.