[Halld] End of the run and a preliminary summary

[Eugene Chudakov]

Dear colleagues,

The accelerator management has decided to stop the 2K operations of
the Central Helium Liquefier (CHL) till the cause of the failure of
the Cold Compressor CC5 has been understood. The investigation may
take a month. This, of course, ended the Spring run.

This cuts the GlueX Spring run from 52 scheduled calendar days to 39
days. In spite of that, the run was very successful. The ABU (
"Acceptable Beam in Use") factor was close to 50% of the calendar
time.  During this run the Hall D equipment has been working well,
meeting the requirements. The superconducting solenoid stayed at 1350A
for the whole period, while in the Spring 2016 it was mostly used at
1200A. A substantial progress in speeding up the front-end electronics
and the DAQ has been achieved since the Spring 2016. The experiment
ran at a ~1.5 higher luminosity than initially planned. GlueX has
obtained a large data sample to analyze and produce physics results!

Another important goal of this run, apart from running GlueX, was to
demonstrate the Key Performance Parameters (KPP) by the Halls B and
C. These requirements have been successfully met.

The CHL problems may affect the next running period - the schedule,
and the beam energy. We may expect some clarification in a month.

Yours,
Eugene

------------------------------------------------------
Eugene Chudakov
https://userweb.jlab.org/~gen/
phone (757) 269 6959  fax (757) 269 6331
Thomas Jefferson National Accelerator Facility
12000 Jefferson Ave, STE 4,
Newport News, VA 23606 USA