Run Coordinator report: spring 2019 w6

RC summary, Feb. 28th - Mar. 6th 2019

During this period we began collecting physics quality data for the PrimEx experiment. We began by using the solid Beryllium target and collecting the required statistics for Compton normalization in the first few days of the week. Following the Beryllium target running we ran for 1 day with the Beryllium foil removed to acquire empty target data which will be used for background subtraction. The final Hall D configuration change during this week was on Friday to install the liquid Helium target, which was performed by the target group. The was initially thought to have a leak, but was investigated and found not to be an issue. The target was left empty and production data was collected over the weekend with the empty target cell. On Monday the target was filled with Helium and production data was collected through the end of my tenure as RC.

Two notable other issues were encountered during this RC week:

• A shift in the CompCal occupancy was observed in the monitoring plots, which was later identified as a misalignment between the FCAL and CompCal which modifies the acceptance of the FCAL relative to the nominal geometry. This will have to be accounted for with simulations of the acceptance.
• The accelerator was having significant vacuum and trip issues in the early part of the run period, which were deemed to be unsustainable. Thus on Tuesday it was decided that the beam energy for the remainder of the run would be reduced to 11.2 GeV to try and reduce the trip rates, which meant most of Tuesday and Wednesday we did not have beam due to the energy change.