Shutdown pquest SNF 2010-04-12 15:01:00: Wafer break

[eenriquez at snf.stanford.edu]

User's quartz wafer stuck to the o-ring.  The o-ring was pulled out of its groove when the system tried to unload the wafer.
Replaced the o-ring (2-149, durometer 50) and replaced the springs.
Helium flow @10 Torr < 0.5 sccm.