[Hallc_running] [New Logentry] RC daily update

sjjooste at jlab.org sjjooste at jlab.org
Sun Oct 14 13:10:02 EDT 2018

Logentry Text:
Stable beam of 35uA yesterday with minor downtime until the middle of owl at 03:00. 
At that point, we went down for 3 hours and after that the accelerator has been struggling 
to deliver a good beam to us, especially after we asked for higher current. 
See here for more info: https://logbooks.jlab.org/entry/3609290

Right before the RC meeting, when checking if the hallc_replay directory was correctly restored 
after yesterday's issues, we noticed the standard.kinematics file had not been updated when we
moved to the last kinematic point. This explains while the lambda invariant mass spectrum looked so
much wider. We replayed all runs with the correct kinematics file during SWING, which doubled our
estimated count of collected lambda events. Everything looks consistent now.

At the end of the owl shift we moved to the next kinematic point as planned. As the SHMS is still at a very
small angle we started with the Al dummy target to get an idea of the rates for LH2. It seemed we should
at least be able to run at 55(+/-5) uA when extrapolating from the last setting

Beam became very bad after we requested higher currents, and around 10:00 the PD called me to tell us 
they cannot currently deliver a stable beam above 37uA. More info here:

We finished taking data at the Q2=3. W=3.14 x=0.25 theta_Shms=6.49 deg kinematic point
and collected 46% of the total statistics goal on LH2 and 100% of the statistics goal on Al dummy.
This morning we moved to Q2=5.5, W=3.02, theta_Shms=6.49. We collected 80% of the Al dummy 
data (took 3 hours) and are now running with LH2. We are expecting to stay in this setting for 6-7 shifts,
potentially with interruptions for beam tuning tomorrow and at least 1 shift of luminosity studies (if the
accelerator can actually deliver higher current).

There will be an RC meeting today at 4:30 pm on the second floor of the counting house.

After the meeting you can find the talking points here:

To join the Meeting:

To join via Room System:
Video Conferencing System: bjn.vc -or-
Meeting ID : 861439920

To join via phone :
1) Dial:
+1.408.740.7256 (US (San Jose))
+1.888.240.2560 (US Toll Free))
+1.408.317.9253 (US (Primary, San Jose))
(see all numbers - http://bluejeans.com/numbers)

2) Enter Conference ID : 861439920


This is a plain text email for clients that cannot display HTML.  The full logentry can be found online at https://logbooks.jlab.org/entry/3609298
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