Run Coordinator report: Fall 2018 w6

We were scheduled to receive 168h of CW beam, we received 69h and of that 53h were acceptable and used. 8h of beam were deemed unacceptable for physics and the remaining hours when beam was available but not used were spent on configuration changes (8h), preparation for the diamond alignment and an access to reset the goniometer camera.

At the start of the week MCC were attempting to re-establish beam to all 4 halls, with Hall C requesting 40-65 uA at times. This proved to be difficult and the beam delivered to Hall D from Wed - Fri was often sporadic, unstable in position and its convergence was not good. Despite this, we managed to align all 4 orientations of the 17um diamond and complete some special studies listed below. At the start of the weekend the trigger rates were found to be higher than expected, but they dropped throughout the weekend as the beam convergence deteriorated further. There were several other issues with the accelerator, and we lost time due to trouble with the injector, RF module failure, cryo module failure and RF trips. However, by the end of the weekend the RF trip rate was good enough that MCC cancelled the RF recovery time planned for Tuesday. On Monday Mike McCaughan and Todd Satogata spent the entire day shift and part of swing shift retuning the Hall D beamline, resulting in dramatically improved convergence and higher rates, which have been stable since then. The photon beam polarization looks comparable with that during the spring run.

Special tasks completed during the week include:

diamond alignment at 0/90 and 45/135 high rate DAQ tests high rate trigger tests CDC HV scan PS trigger studies TagM threshold scan

and we collected 5E9 production triggers, 2E9 since the retune.

More details can be found at https://halldweb.jlab.org/wiki/index.php/Run_Planning_Meeting_Notes,_Sep_20-27,_2018 and https://halldweb.jlab.org/wiki/index.php/Run_Planning_Meeting_Notes,_Sep_28-Oct_3,_2018