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Log entry time 17:23:54 on February 02, 2011

Entry number 217910

keyword=Beam: Problems with beam ... not restored yet since 15:30

MCC had informed the shift crew that the beam was down due to a "large dipole trip" - aka Nur's HCLog entry at 16:14. Beam is still not back an hour later. Jay just called and informed us that it was the Hall B dipole that crashed, which has nothing to do with us, but that the real problem is that when they completed the Hall C slit scan that was begun at 15:30, aimed at optimizing the beam delivery for us overnight, they were not able to re-establish the beam conditions that we were using this afternoon. Restoring the previous settings exactly has produced a very unstable beam, unacceptable halo now everywhere etc.

Reza has been called in to try and get back to where they were prior to 15:30.

Our goal tonight is to get back to 110 uA with acceptable halo rates on halo3 and halo4 and non-damaging rates at the Compton region. Stay tuned... (no pun intended)



A copy of this log entry has been emailed to: armd@jlab.org,carlini@jlab.org,rob@jlab.org