There is an issue of maintaining vacuum in the StanCam and FIES cryostats that are cooled with a cryotiger. As these are stand-by instruments, one would like to avoid having sudden problems with the vacuum, but at the same time one wants to have the instruments available at all times. Basically one wants to define a period within which we are fairly sure no loss of vacuum will occur and schedule the pumping of the cryostat when most convenient (e.g., during an ALFOSC run for StanCam or a SOFIN run for FIES, or maybe during a time of year when the days are sufficiently long to do the whole operations before the start of the next night).

Thomas Augusteijn 2006-12-04