Log entry time 07:57:10 on January18,2009

Entry number 256617

Run Coordinator Report for Jan 16(Swing)-17, 2009:

# Polarity status of the spectrometers: BigBite -ve (for e-), L-HRS +ve (for &pi+)

# &pi+Transverse  mode with the half-wave-plate IN

Charge Accumulated Summary So Far



                     Half Wave Plate     Charge Expected (C)  Charge Accumulated (C)   Comment



&pi+ Transverse          IN                       3.5               4.5                 -

&pi+ Transverse          OUT                      3.5               3.66                 Done  



Overall Plans

1. Will stay at Pi-plus Transverse mode until Sunday 10:00 (Jan 18).

2. Will go to Pi-plus Vertical mode on Sunday Day shift (~10:00).

3. Will do Moller measurement either on Tuesday or Wednesday.

4. Will do positron runs on Thursday (Jan 22) Day/Swing and Swing/Owl(Friday) where



   Day/Swing [total one shift, starting ~11:00]: BigBite +ve polarity and L-HRS +ve

   Swing/Owl [total one shift, starting ~19:00]: BigBite +ve polarity and L-HRS -ve



5. Friday (Jan 23) Day: BigBite will be back to -ve polarity, L-HRS stays at -ve polarity.



Jan 16(Swing), 2009

Activities

-Compton rate started degrading towards the end of the day-shift by fluctuating between a couple of hundred Hz to a kHz

- Otherwise a smooth production in &pi+ Transverse mode



Beamtime Accounting:

         ABU        BANU    BNA 

Swing    7.32       0.37    0.31



Jan 17, 2009

Activities

- R. Michaels et. al., during early Owl shift, fixed most of the deadtime, scaler overcounting issues 

  by taking an access into the hall (suspect a loose cable).

-10:40-13:40 BigBite High Voltage mainframe swapped with a working one. The HV problem started 

 late Owl shift, but only noticed at 10:30. Also ESR-work commences at 11:00 and finished at 12:20. 

 Takes additional time to bring the HRS magnets back to normal due to cryo-instability.

 During this downtime, various people worked on the deadtime, BB-cherenkov, RICH and other pending issues 

 in the hall. Also, Yi did target internal temperature test.

-Production in &pi+ Transverse mode

-The Compton rate becomes worse: ~10 kHz/uA, urged MCC (12:30) to investigate into 

 the beam quality while we are still down to bring the magnet's cryo-level stable after the ESR-work.

-13:10 Magnet cryo-levels are ok.

-14:00 Before taking production data, again asked MCC to tune the beam for Compton quality (photon rate <500 Hz/uA).

-14:30 Compton stops working (suspect too high background), asked to stop beam tunig, resumes production 

 while troubleshooting Compton problem.

Beamtime Accounting:

         ABU        BANU    BNA   Comment

Owl      5.81       1.11    1.09  Took access to fix deatime, scaler overcounting, etc.

Day      2.06       3.70    2.24  Took access to swap BB HV mainframe, other various works during ESR down.  

Swing    7.51       0.23    0.25