Since April 2006, the 354 meter ring of vacuum chambers in the SOLEIL synchrotron has been closed with permanent vacuum chambers. These vacuum chambers, mainly of stainless steel or aluminum covered on the inside with NEG materials, held the machine’s first stored photons. We were able to realize the beneficial effect of these NEGs on the quality of the vacuum, both static at the start (10lo mbar) and dynamic during the first ampere-hours (logical increases of one or two orders of magnitude). At the beginning of summer 2006, the cumulative dose received by the walls of the vacuum chambers reached 5Ah, and the dynamic vacuum was already beginning to improve. The number of molecules desorbed by the primary photons emitted by the first beams was already decreasing. The trend is toward favorable cases measured during previous experiments with the ESRF.
During the summer 2006 and the first major technical stoppage, several improvements were carried out, particularly the addition of 2 insertion components: U20 (vacuum power supply) and HU256 (new vacuum chamber with NEG). The temporarily shut-down storage was resumed at the beginning of September 2006 and the SOLEIL storage ring, as well as its numerous vacuum chambers, was finally ready at the end of the summer to resume storage and its path toward a weak photo-desorption necessary for good functioning and a lifespan compatible with the needs of future users. Initial results are already very satisfying.
