X-ray lithography source (SXLS) vacuum system

In 1988 Brookhaven National Laboratory (BNL) was awarded a contract to design and construct a compact light source for X-ray lithography. The contract is for an electron storage ring designed for 690-MeV 500-MeV 500-mA operations. It has a racetrack configuration with a circumference to 8.5 m. The machine is to be constructed in two phases. Phase I (200 MeV, 500 mA) is primarily for low-energy injection studies and incorporates all-room-temperature magnets. For phase II the two room-temperature dipole magnets are replaced with (4 T) superconducting magnets and operation is at 690 MeV. The vacuum system for this machine is described. This vacuum system must satisfy three basic requirements. First, it must provide a dynamic pressure (pressure with stored beam) of 10^-9 torr or better to minimize electron-beam-residual-gas interaction. Second, it must be able to recover from venting to atmosphere, deliberately or accidentally, in a reasonably short time. Third, it should require little operator intervention for normal operation