[Halla_parity] PREX status / plans

[Robert Michaels]

Dear Colleagues

At present, the target has been warmed up to drive
away the ice that had formed on it; most experts
think this was caused by the few days the target
vacuum was in the 1e-4 Torr range.  Tomorrow Ed
Folts will try to pump down and do more leak checks
and possible leak repair.  If the vacuum recovers
to an acceptable level -- which looks likely to me
-- then we have one requirement to continue running.
In that case we'd cool down the target late Friday.

Another factor is the Left-HRS magnets - dipole
and Q3, which are not working at the moment.
Jack and Howard are trying to repair the controls
system, which is thought to be radiation-damaged.
If the magnets are fixed by tomorrow and if we
have good vacuum, we will run production this
weekend.  If the magnets are not fixed we have
more decisions to make at the 3 pm Friday meeting.

We've been discussing whether to replace the O-ring
or continue running with the silicone patching.
Right now we're leaning towards the latter, but
it depends on what happens tomorrow with the leak
checks and magnet repairs.

Bob Michaels