[BLAST_SHIFTS] Shift summary 06/26/2004 B (9-17)

From: Electronic Log Book (elog@blast05.lns.mit.edu)
Date: Sat Jun 26 2004 - 17:25:14 EDT


Operator: franklin

This shift was divided between data taking with unpolarized deuterium and beam
tuning. During the course of the shift, substantial progress was made on reducing halo and improving lifetime to levels approaching those seen before the shutdown. There remains difficulty with injection above 95 mA. A number
of things have been tried, but this limit has been stubborn so far.

Two runs were taken with relatively lousy beam this morning (8299, 8300). The
more recent runs (8301, 8302) were taken after the retune. Runs have been interrupted intermittently by wire chamber trips, but for the most part they are
staying. Frequency seems to be diminishing with time. Most trips are R24 and L5.

The backscatter rate in the polarimeter is very good (2 kHz/mA with 1.5" absorber). The signal-to-background ratio is ~5:1 and error bars are less than .05 per fill. The change is due to a combination of beam tune, the calorimeter and improvement of transmission in the laser line. Polarization is about .65
although it may have actually dropped since this afternoon's retune. Will take
more data to verify. The left and right-handed helicity signals for the Compton
laser are backwards (resulting in sign error for beam polarization). This needs to be rectified before we go to polarized data on Monday.



This archive was generated by hypermail 2.1.2 : Mon Feb 24 2014 - 14:07:31 EST