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- Progress with NEG-coated Vacuum Chambers
Progress with NEG-coated Vacuum Chambers
Thanks to a collaboration with CERN during the last few years, there are now 10 insertion device vacuum chambers in operation on the ring that are pumped by a non evaporable getter (NEG) coating. The getter material is made of titanium, vanadium and zirconium, which provides both a low photo desorption and pumping. It is deposited on the inner wall of the chamber by magnetron sputtering. The pumping efficiency of one such coating was previously tested with some 11 mm internal aperture chambers by measuring the bremstrahlung generated on the axis of the straight section. In 2001, the NEG coating was applied to the 8 mm internal aperture vacuum chambers. Five of these narrow chambers are now in user operation. All 8 mm chambers were pre-conditioned on a dedicated straight section and then moved to their final destination. The other five NEG coated chambers are 15 mm thick and made of aluminium. To date, all chambers have been coated at CERN. The vacuum group is now developing its own facility to coat the future chambers in house. This will also serve to investigate the coating of other types of storage ring chambers such as the quadrupole and crotch vacuum vessels.