Design and characterization of high capacity nonevaporable getter pumps embedded inside the interaction regions of DA Phi NE

The DA Phi NE Phi-factory is a twin-ring 510 MeV e(+)e(-) collider facility under commissioning at INFN-LNF in Frascati. With a stored beam current of 5.3 A, a mean pressure of 1.3 x 10(-9) mbar is required in each ring. For the KLOE interaction region, where a mean pressure of the order of 1.3 x 10 (-10) mbar is required, an embedded nonevaporable getter (NEG) pump with a CapaciTorr(R)-type structure was chosen mainly because of the unavailabilit y of room for the installation of lumped pumps and to take maximum advantag e of the sorption capability of the NEG pump for CO in the UHV operating co nditions of the machine. A NEG pumping system of the kind discussed in this article seemed to be particularly suitable for the KLOE experiment, where limited servicing and high reliability is required. In this article we repo rt on the design and characterization of both the first pump prototype, fit ted with St-172 NEG alloy and the final pump version, where St-185 NEG allo y was used. (C) 1999 American Vacuum Society. [S0734-2101(99)11904-3].