Performance Characteristics of Lumped Nonevaporable Getter(NEG)Pump.

Abstract

A prototype of the lumped NEG pump (LNP) designed as a main pump of the crotches and absorbers of the SPring-8 storage ring was manufactured with 14 nonevaporable getter (NEG) modules and a cylindrical pump body made of aluminum alloy. Vacuum Performance and operating characteristics of the LNP have been tested. Initial pumping speeds of the LNP for H2, CO, N2 and CO2 were typically 3 m3/s, 1.7 m3/s, 1 m3/s and 1.3 m3/s, respectively. The experimental results were compared with the pumping speeds calculated by the Monte Carlo method. Equilibrium characteristics of the LNP in the activation period were studied to obtain basic data for the design of the auxiliary pumping system, and to set a pertinent activation schedule for the LNP. Operating characteristics such as the power consumption of the NEG modules and the temperature rise of the adjacent chambers including the aluminum alloy pump body during the NEG activation were also investigated.