Log entry time 21:56:14 on March 12, 2012

Entry number 366045

This entry is a followup to: 365730

A run-plan for tonight, Wed, and Thursday is posted in Halog 366034. As I write this (9:30pm) we are wrapping up the BCM calibration. We will continue with a Moller, follow up with BPM calibrations (HARP 1HA05 was repaired during today's access), and a BCM calorimeter run. The remaining OWL shift will be spent taking inelastic data.

The target's slow depolarization mystery is explained by a BCM calibration over estimating our beam current on target. It was closer to 15--20nA, not the 55nA reported by 1H00. This was not a problem for us since we were DAQ rate limited -- in fact, the persistent high polarization really improved the figure of merit for this GEp setting.

We were unable to run straight through optics in this chicane configuration as initially planned. We shuffled the runplan and will be using the Tuesday chicane move to go to the Straight Through setting. That time overlaps with an extended Beam Study period, so we don't lose any beam time. SWING and OWL will be spent on our planned Optics studies and possible dilution/ background runs.

We will make a second chicane move on Wednesday DAY to Position #5 (2.2 GeV, Target field = 2.5 T, Target orientation = 90 deg). This will set us up for our first g2p production running.

Issues to watch for (these are also on the whiteboard):

• Shift staffing is a still a problem! It's looking better in the short term, but there are many vacancies starting March 18 -- less than a week away. Come on folks, step up and sign up! Really -- no kidding.
• Beam leakage from Hall C is well under control now. We need to be vigilant and make sure that Hall A Laser slit is set to 14 for our production running. The shift crew are requested follow a quick bleedthrough check every 4--5 hours just to be safe.
• The IHWP will be flipped at Hall C's request every 4 hours. Hall C and/or MCC should inform us when this happens so we can log the change and stop/start our runs. Hall C would like to shorten this flip interval in the future -- we are working on a procedure and frequency that will work for both Halls.
• The target magnet current spontaneously drops by ~0.5A occasionally (look in Halog for "Target Current" entries). The Target operator needs to watch for these and know how to correct the issue -- ask the TO how to do this when you come on shift if you don't already know. This is likely to be a bigger problem when we return to higher currents. (We will attempt to add some shielding around relevant electronics during Tuesday's access.)