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User name Tang
Log entry time 14:31:00 on March 14,1998
Entry number 4339
keyword=BCM Calibration
Dave Mack just pointed out that if we are running below 25 microA beam current then more frequent BCM calibrations are needed to reduce systematic errors. He noticed that the last calibration was done on 3/9 so that he suggested to do it again soon within next 24 hours.
We have used about 15 microA for runs with SOS set at 15.46 degrees this morning. Currently SOS is at about 42 degree and we are able to run with 25 microA current but the S/A ratio was only about 0.6, thus we decided to lower the current to 20 microA and check on S/A again. This means we may continue to run with beam current below 25 microA.