[Halld] Commissioning Update

[David Lawrence]

Dear Collaborators,

  The accelerator was able to deliver good beam to Hall-D over much of the weekend. Unfortunately, we
had a Solenoid trip on Saturday morning and another early Saturday evening. The two trips indicated
that they were caused by different things. Steps were taken to address the first (cryo) but more work is
needed to diagnose and address the second. Consequently, we ran with no field or very low magnet current
for Saturday and Sunday.

  Nevertheless, we were able to take advantage of the beam in the following ways:

- Significant progress was made on the Trigger (thanks to Alex Somov)
   + Tagger TDCs timed in
   + BCAL trigger established and working
   + BCAL+FCAL trigger established
   + Multiple, simultaneous triggers (FCAL, BCAL, FCAL+BCAL)

- Lots of no-field data
   + straight tracks for alignment
   + calorimeter data (with BCAL trigger)

We’ll continue with diagnosing the magnet problem today and hopefully implement any repairs in
order to restore it to full field. The Hall is scheduled to be open tomorrow while the accelerator does
beam studies so we’ll have to see how things go today with the experts before forming a run plan for
the next few days.

 As a reminder Alexandre Deur will be taking back the reins as Run Coordinator today and I’ll take over
for him again on Friday.

Regards,
-David Lawrence