Fuse failed on main 480 disconnect for the BLAST power supply around
midnight. After that was replaced, the 480 breaker on the switchgear
wouldn't reset. That was repaired around noon, and beam was back at
1pm. We ran cosmics for over 3 hours this morning.
Since we were down anyhow, and the nozzle was expected to clog within 24
hours, Genya started warming up the nozzle this morning.
Since 1pm we have been running empty target, now filling to 175 mA. The
nozzle is cooling now. When it is ready, we will resume running ABS
hydrogen at 48 degrees. Hopefully the DAQ live time stays above 70% even
at 175 mA (take the ratio of BDCCT and DCCT from the scaler screen). Genya
thinks he'll be able to switch to hydrogen around 5pm. Watch to see if
ligit stays high for the whole 5 minutes between target flips. There was a
rare and random problem with the MFT being out of sync in one of the 2
target states; perhaps rebooting the ABS computers yesterday helped?
Compton false asymmetry is fairly small, but polarization is around 60%,
after just a few measurements since the beam has been back.
Please keep pol.log and RUNLIST-H2.2 up to date. Watch twl and twr to make
sure 3 l/m helium flow still gives us good efficiency for the long drift
distances.
Karen
This archive was generated by hypermail 2.1.2 : Mon Feb 24 2014 - 14:07:32 EST