[Xrayops] More information on operational difficulties

[APS Experiment Hall X-ray Operations Problem List]

As stated in the last message, we think there is a possibility of stored
beam by 8AM tomorrow (3/28).  However, it is very difficult to be
certain of this, because rf conditioning is a very unpredictable
process. The actual time of beam delivery could conceivably be sooner or
much later than that.

The problem, which developed on Saturday, was originally a pinhole leak
in a ceramic on a high power coupler.  We limped along with this until
Monday, when the coupler was replaced.  Rf conditioning began on Tuesday
after necessary electrical repairs were completed. As you can see on the
following link, the progress of conditioning is anything but smooth,
which is quite typical
http://aps.anl.gov/asd/oag/AutoSavedPlots/BRFCavityForwardPowers.html
On this plot, the total power is the yellow curve labeled "K". We need
to sustain about 350 kW to support 7 GeV.  We are presently running at
just under 250 kW.

Once 7 GeV beam is available from the booster, we'll make an
announcement.  We need to ready the storage ring for 24 bunch operation,
which will take about 2 hours after needed personnel arrive on site.  

--Michael Borland