26 December 2007

RHIC Startup:  There was a high-level RF problem this morning at the beginning of the APEX.  The Yellow Accelerating cavity, YA1 lost voltage.   This follows yesterday's continuing RF troubles with the X1, X2 YS3 cavities.  When the X2 common cavity drops out, some of the Yellow beam and much of the Blue beam is debunched.  Several times this occurred.  There was a beam loss that tripped the BLAM early this morning allowing APEX to start early (5:30).  It also caused a real quench. 

Also, the continuing problem with the power supply for the Sextupole yi3 reoccurred.  It lost its fiber optic control card for its power supply.  Replacing the card returned functionality.

APEX will study the effect of squeezing the beta* in the Blue beam today. 

PHENIX reports a failure in the North Muon Arm.  A 15 minute access resulted in smoking a transistor in the crate supplying low voltage to the North Muon Arm.  A longer access has been requested, >1 hour, which will take place at the end of APEX or during any extended downtime during APEX. 

Peter Ingrassia reports that the integrated luminosity for Christmas Day exceeds that of any day recorded so far.