FURTHER DEVELOPMENT OF THE CELSIUS UHV SYSTEM

The cluster-jet target assembly and several other parts of the vacuum system have gone through a major reconstruction to fulfill the needs o f some approved physics experiments in the ring. Specially designed No n-Evaporable Getter (NEG) pump modules have been developed and install ed in the electron cooler. To cope with the heavy gas load from a hydr ogen pellet target, which is now being developed, further NEG modules are considered, combined with cryopumps for differential pumping aroun d the pellet target.