[Halld-physics] Run Coordinator Report, March 27 - April 3

[Stuart fegan]

Run Coordinator report for 3/27 - 4/3 follows

Regards,

Stuart (Former RC)

We were scheduled for 156 hours of CW beam, of which 109.4 hours (70%) 
was delivered to Hall D. Of this, we used 103.9 hours (ABU), or 67% of 
the scheduled beamtime.  Around four hours of our unused beam was due to 
repeated accesses over the weekend related to the solenoid manifold 
turbo pump, with a further hour and a half related to typical DAQ crash 
recovery.  The remaining unused beam was due to the switch we made from 
full to empty target operations and back again, and radiator changes for 
our harp and collimator scans.

We have now collected 99.5% of our expected data for the spring 2019 
portion of the PrimEx run, versus 80% of the schedule. This is mainly a 
consequence of the efficiency of the machine exceeding the expected 50%, 
rather than an indication of the number of triggers collected.

Detector performance was excellent overall, and after an access on 
Monday for some FCal base replacements, the FCal was "perfect". An HV 
module for the CCAL failed on Wednesday morning, and required 
replacement. The FCal access overlapped with the planned beam down 
period for beam studies, but the CCAL HV replacement required an 
additional access.

Beam parameters were mostly good, however we have seen unexplained 
fluctuations on a downward trend in the event rates. The beam studies/RF 
recovery day on Monday saw the rates recover, investigations continue in 
conjunction with MCC experts, and it is hoped we can come up with an 
explanation.


-- 
Dr Stuart Fegan
Postdoctoral Researcher
George Washington University/Hall-D
F351, CEBAF Center

E-mail: sfegan at jlab.org
Telephone: (757)-269-7473