Log entry time 22:34:27 on May 07, 2004

Entry number 84408

Run Coordinator Daily Report for 6 May Owl to 7 May Swing

Summary

GMS is still off.
 

Significant News

On Wednesday we have had a meeting with injector and accelerator experts to draw a test plan for further leakage studies. We came to the conclusion
that we needed several periods without Hall A running:

•  one period of 4 hours to measure Hall B leakage with a high precision by inducing large beam asymmetry using thr RWP (Rotatable Wave Plate)
•  another period of 4 hours for studying the sensivity of the Hall B leakage into Hall C  as a function of Hall B operating parameters (laser power, slit opening...)
• a long period of 3-4 shifts to validate with good statistics the method which consists in measuring the asymmetry in the time bins outside the physical region to

correct under the elastic peak.

At 17:00 Hall C was closed and we started putting things back to normal running conditions.

At 18:25, SMS fast dumped. Kaz and Damon were called but they experienced difficulties with  one analog input modules.
After they fixed the problem,  SMS quenched again at 22:45 and at 03:16. At that point we decided to wait until Thursday for consultation of magnet experts.
The faulty component  (a CPU) was changed during the morning and magnet was back to full current at  11:00.
The leakage studies are postponed to Saturday Owl, with the approval of JLab management.

Target boiling studies completed
 

Short term Plans

• Resume  threshold studies with IHWP OUT after detector tests are completed Thu around 17:00.

LH2 target, standard running conditions except thresholds.
Due to differences in FR and NA splitters the thresholds of the FrAm detectors have to be higher than the FR thresholds. A new Reference file has
been created with FR thresholds at 100 mV and FrAm thresholds at 140 mV (Reference_FiB_Buddy_Fr100mV_FrAm140mV ). So for the thresholds studies:
    - load  Reference_FiB_Buddy_Fr100mV_FrAm140mV
    -set NA threshold to  14
• Run 1 shift at 40 uA with IHWP = OUT until 23:30.
• At 23:30, stop the run, revert to standard thresholds and Reference file:

- load  the Reference_FiB_Buddy
- set the NA thresholds to 7 and FR thesholds to 50mV
Start a short run and check that ToF spectra are OK.
 
• At 00:00 on Saturday, start the leakage studies with Hall A off, Hall B on until 08:00. Follow the detailed run plan by Mark Pitt
• At 08:00 resume thresholds studies IHWP=OUT (one last run during Day Shift until 16:00) with same settings as above..

 

 

SETTINGS TO BE USED WHEN RUNNING WITH NO CURRENT IN HALL C

• Lumi gain has to be multiplied by 1000, this being obtained by gaining a factor 100 using an increase in HV and another factor of 10 by
changing the gain of the lumi amplifiers. For that:
            - Switch from standard  lumi  HV file HV.2004-02-19.lumi_halo_on.hvcto HV.lumi_highhigh_on.hvc
            - Change the 6 lumi amplifier settings in Electronics Shack  upstairs (if you don't know how to do,ask Mark Pitt or Jianglai or the RC).
• change BCM 1 and BCM gains from 3==>5 in rack CH03B11 in Hall C electronics room. These will most likely not work as sensivity

is 1 uA only for these settings but it does not hurt.
DON'T FORGET TO SET THESE BACK TO NORMAL CONDITION WHEN RUNNING AT HIGH CURRENT.

Longer term Plan

• Around Saturday noon we are requested to submit to Larry Cardman  a report of the tests done during the Owl shift and a justification for longer running  
  (several  shifts) without Hall A as outlined above. Detailed run plans will be given in due time.
• Next week: Transverse running on Monday-Tuesday-Wednesday if no other urgent business.
• Next week (tentatively on Tue or Wed): one full Day Shift will be devoted again to SOS tests.

 

 

Concerns

No concerns, life is just beautiful   :-)