[Halld] Run Coordinator Summary: Sept 26 - Oct 2, 2018

[Naomi Jarvis]

Dear Collaborators,

Here is the summary from the last week of running:

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


Best regards,

Naomi Jarvis.
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