71. V.V.Anashin, A.N.Dranichnikov, R.V.Dostovalov, A.V.Evstigneev, L.G.Isaeva,
A.Krasnov, V.S.Kuzminykh, L.M.Schegolev, Yu.M.Shatunov (Budker Institute of Nu- clear Physics, Novosibirsk, Russia) The vacuum system of the VEPP-2000 storage ring Perimeter of VEPP-2000 is 24.4m only and the average density of SR flux is 1.2*10E19 photon/s per meter and SR power is 1000W per meter at maximum design currents Ie- =Ie+=200mA. Special SR receivers are used along the total length of the ring except in- teraction regions and RF cavity. An intense gas load due to photon stimulated desorption should be compensated by high enough molecular pumping speed. VEPP-2000 high vac- uum system consists from different parts: 8 vacuum chambers inside the dipole magnets, vacuum chambers of the solenoids, experimental and technical straight sections and vac- uum chamber of the RF cavity. VEPP-2000 high vacuum pump system consists from 16 ports with ion-getter pumps PVIG-100 situated on the bending magnets vacuum chambers edges; ion- getter pump PVIG-250 connected with resonator area; 4 cryopumps presented by solenoid cold surface. To prevent SR heating of cryosurface at T=4.2 K a perforated cooper liner have been made that is cooled by liquid nitrogen. Slits in the liner should provide linear pump speed at rate of 5 l/sec/cm for nitrogen. Cold surface at 4.2 K is the ideal pump for all residual gases except hydrogen, since after adsorption more than one monolayer of hydrogen at T=4.2 K saturated vapor pressure the one reaches 5*10E-7 Torr. In spite of such circumstances calculations showed the beam lifetime will be deter- mined of CO residual pressure. By now the vacuum system has been made, assembled, pumped and baked in-situ at 200 . The obtained average pressure in vacuum chamber of storage ring is better than 10E-9 Torr. But pressure is about 10E-9 Torr inside resonator vacuum chamber baked in-situ at 120C. Dr. Rodion Vladimirovich Dostovalov: R.V.Dostovalov@inp.nsk.su
P.72. S.Krutikhin, V.Arbuzov, D.Starostenko (Budker Institute of Nuclear Physics, Novosi- birsk, Russia)
Preliminary power amplifier for HF generator of small ring Siberia-1
Semiconductor preliminary power amplifier used for Siberia-1 booster HF power genera- tor excitation. Maximum output power at operating frequency is 500W. A distinctive fea- ture of this amplifier is an ability to operate at frequencies from 1MHz to 40MHz at maximum output power of 400W.