Run coordinator daily report December 8th, 21:00

Since December 6th, we at the same time gain some confidence in our detectors and got very confused by the dead-time measurement.
And as usual , night shifts have been tough :
- IOC troubles : we lost 3h because IOC G0A crashed and needed a button push reboot, but no body could find it in the hall. Also the reboot of an IOC by the MCC guys does reboot our target ioc. this should not happen and is associated to a bad cabling.
-OTR foil : there is an OTR along the Hall C beam line. For our run ,the OTR should be retracted but it was found on by Gregg. The check list will be updated such that it is checked that the OTR is retracted. Please fill the check list at least once a shift.
- DAQ confusion : Paul has written instructions and some instructions. Yes let us admit it, the daq setting can be confusing. If you are confused or the daq crashes on you each run, contact Paul (Day and night, sorry Paul).

The owl shift on December 7th was devoted to the calibration of the luminosity detectors shouting on the fly-swatter (solid target). We had in plan to maybe use this solid target to do the dead-time measurement, but the rates at 40uA produced by the fly-swatter are 15% of the rates at 40uA on lh2 target. so we decided to revert to the lh2 target to do dead-time studies. During the fly-swatter measurement, the charge asymmetry feedback went "berserk" and this repeated it self on the swing shift of the 7th. The charge feedback program has been changed such that if the computed voltage for the IA is "unphysical", the feedback system will turn itself off . Please keep an eye on the charge feedback display. Document if you find that the feedback is turn off. Finally the IOCG0A crashed and they spend the rest of the night chasing the ioc down in the hall.

The day shift and owl shift on December 7th was devoted to dead-time measurement. The data were taken on lh2 target with a raster of 3*3 mm and a pump speed of 42 Hz. At that time it was believed that the spot size did matter and this is why the day before we had change the spot size to be ~ 100 um on target, since this day and because of all the protest of my collaborators, I tried to chase down the root of this believe but I was unable to find it. Kaz has protested that the width of the position asymmetry as increased significantly since the beam size spot change. So ok maybe we will revert to a smaller spot size, please send me your comments. So the dead-time studies when on and pretty early on it was found that the results the normalized yield would drop by 25% when the beam was ramped up from 0 to 40 uA. See the numerous entries by Jianglai or Damon's Analysis coordinator report (at the end). I'm afraid we will have to repeat most of those measurements.

On the night shift of December 8th the dead-time studies continued. Later on the second try for Fr gain calibration was started. since the first try, Herbert figured out that the ADC reading part of octant 2,4,6 and 8 was behaving. This ADC has been changed. The output of the second try (1rst iteration looks very successful). Later on the 8th, Serge and Benoit have cross-check the ADC gain measurement with scope measurement. There results do agree so well with the ADC calibration that it rejoiced me. Ok we again confirm the lost in gain for detector 2,3 and 4.

On the day shift of December 8th, the moller has been brought up on line. Dave Gaskell and Tania Horn measured a polarization of 60% when Hall B is on and 70% when Hall B is off. The Moller is basically operationnal even though the efficency of some of the hodoscope channels need to be improved.

The plans for 24 h :
- perform RWHP, IA and PZT scan.
- do second gain iteration on French octants
- if time before 8 am : position halo target in beam
- 8:30 am : hall C to controlled access to survey the girder
- during the access, Dave McKee will turn up the GMS.
- during the access, the polarized group will tweak the wave lenght of the laser to improve the polarization.
-after... will see. If the girder is found misalign and is realigned , we will do the first item of the run plan (the thing we should have done last tuesday night...)

your RC,

Julie