Run Coordinator report: Summer 2020 w2

RC summary 08/05/2020 - 08/12/2020

This week started after the interruptions caused by Hurricane Isaias. We were scheduled for 112 hours of beam this week, but only got 37 hours of acceptable CW beam on target. This corresponds to 33% of the scheduled time. We were able to use about 29 hours of the beam (26% of the scheduled time). Major causes of down time on our side included a fault in the goniometer controller which required access to the tagger hall, DAQ problems and problems with the configuration of the harp scan GUI. In 32.5% of the total scheduled experiment hours to date, we only collected 10.8% of experiment data so far. This number was determined for the Summer 2020 run alone, not the full GlueX-II experiment. It does not take into account a possible extension to compensate for the initial loss.

This week, the main task was the general beam line and experiment check-out to start stable production running with 350nA beam current. After a thunderstorm on Wednesday evening, the beam was recovered around midnight. We performed a harp scan and checked the radiation levels, which were acceptable. Unfortunately, the tagger microscope was left in high gain mode when the expert lost power at home during the Hurricane. When this was fixed, the coherent edge of the diamond was checked for all 4 orientations. The trigger was also checked, but a scheduled pass change interrupted the completion of HV scans for TagH and PS. Due to several issues on the MCC side, the beam could not be recovered before Saturday morning. Another harp scan was delayed by a wrong configuration setting in the GUI, which was resolved by the expert. In addition, the HOSS system stopped moving files which quickly filled up the disk. It had to be temporarily disabled, with the DAQ writing directly to raid. This was fixed around noon, but beam tuning to hall A prevented us to start production. During the swing shift, Hovanes and Richard commissioned the active collimator to work with bias voltage, which completely removes any charging-up effects after beam trips and greatly improves the stability of the beam position. On Sunday, we could finally complete the first cycle of production data. It was noticed that the coherent edge for the -45/45 orientation was not optimal, and a movement of the spot position in the diamond for these orientations was proposed. We still continued taking data whenever possible, with several interruptions due to the 5th pass separator. During the maintenance day on Tuesday, crews worked on the tagger microscope, the FCal bases, the GEM TRD and the installation of test crystals for the FCal insert. After the beam came back, the controller responsible for the goniometer and the amorphous radiator got stuck during a harp scan, which required a manual intervention in the tagger hall. Production could finally resume on Wednesday morning. The movement of the beam spot for the -45/45 diamond orientation was done on Wednesday afternoon after my tenure ended, which made the experiment completely ready for production.

Thanks to all on-site and monitoring shift crews, experts on call and everybody working in the hall during this important week. We got GlueX back online!