AVS 45th International Symposium
    Vacuum Technology Division Tuesday Sessions
       Session VT-TuA

Paper VT-TuA8
Design and Characterization of High Capacity NEG Pumps Embedded Inside the Interaction Regions of DA@PHI@NE

Tuesday, November 3, 1998, 4:20 pm, Room 329

Session: Drag Pumping and Transition Flow Phenomena
Presenter: R. Giannantonio, SAES Getters S.p.A., Italy
Authors: R. Giannantonio, SAES Getters S.p.A., Italy
P. Manini, SAES Getters S.p.A., Italy
F. Mazza, SAES Getters S.p.A., Italy
R.M. Caloi, SAES Getters S.p.A., Italy
D. Dominoni, SAES Getters S.p.A., Italy
A. Clozza, Infn Lnf, Italy
L. Zanin, DG Technology Service, Italy
Correspondent: Click to Email
The DA@PHI@NE @PHI@-factory is a twin ring 510 MeV e@super +@e@super -@ collider facility under commissioning at INFN-LNF in Frascati. With a stored beam current of 5.3 A, a mean pressure of 1*10@super -9@ Torr is required in each ring. To cope with a total gas load, mainly consisting of CO, of 1.2*10@super -4@ Torr*l*s@super -1@ for each of the electron/positron ring, sputter ion pumps and titanium sublimation pumps with a total pumping speed of about 1.2*10@super 5@ l*s@super -1@ were installed on each ring. For the KLOE interaction region, where a mean pressure of the order of 1*10@super -10@ Torr is required, an embedded Non Evaporable Getter (NEG) pump with a CapaciTorr@super TM@-type structure was chosen mainly because of the unavailability of room for the installation of lumped pumps and to take advantage of the utmost sorption capability of the NEG pump for CO in the UHV operating conditions of the machine. A NEG pumping system of the kind discussed in this paper seemed to be particularly suitable for the KLOE experiment, where limited servicing and high reliability is required. In this paper we report on pumping speed measurements performed on a first pump prototype, fitted with St-172 NEG alloy, featuring sorption rates as high as 5*10@super 3@ l*s@super -1@. We also discuss on the design and characteristics of the final pump version, where St-185 NEG alloy is used. Computer simulations of the pressure distribution inside the interaction beam pipe are also shown, demonstrating the effectiveness of the selected technical solutions.