Modern residual gas analyser (RGA) Applications and developments in the operation of particle accelerators and experimental facilities

Abstract

When designing a particle accelerator or storage ring the ultimate vacuum pressure is a prime consideration. This is because the better the vacuum, the fewer the number of collisions between the beam and the residual gas molecules, resulting in a longer beam lifetime—a significant criterion. The total pressure readings from BA gauges are useful for pressure distribution data, but an RGA is required to monitor the gas species. The data which RGA’s provide is useful, not only to the vacuum scientist, but everyone connected with the construction and use of a synchrotron.It is usual to employ RGA diagnostics in the early stages of machine construction. A typical sequence of tests would be for leak checking, glow‐discharge and bakeout monitoring, re‐checking for leaks and for contamination (either hydrocarbons or cleaning solvent). When a machine is being commissioned, the RGA can monitor for water to vacuum leaks (water cooled absorbers). Later, when the machine is operational, the RGA can show, via the local...