User name V. Sulkosky
Log entry time 15:35:36 on April13,2008
Entry number 231765
keyword=Beam Instabilities and HV TripsStarting at 14:07, we have experienced four trips of the BigBite HVs
due to beam position instabilities in 1H04A and 1H04B Y positions.
The orange curve in the attached snapshot shows the BPMB Y position.
After a beam trip and recovery, the Y position sometimes shoots up to
about +4 mm, which has caused the BigBite dE, E and WC HVs to trip
off.
I have consulted with MCC and the RC has also spoken with them. From
Elog # 1424973, the problem seems to stem from an RF instability. The
energy is different immediately after a recovery from where it was
before the trip occured. MCC will bring Hall C up first to establish
the energy lock, which they hope will improve our position stability
after a trip recovery.
FIGURE 1
