[Hallc_running] [New Logentry] RC daily update

simona at jlab.org simona at jlab.org
Thu Oct 4 10:20:07 EDT 2018

Logentry Text:
At the end of the day shift yesterday we lost beam for a while due to vacuum issues in the accelerator. Beam was restored around 4:20 pm and we continued taking data on LH2 at SHMS theta = 10.74 deg, Q2 = 2.115, W = 2.95, x = 0.21, high epsilon setting. Then around 17:15 pm the PSS dropped in the North Linac. From MCC it sounded that it could take a while to recover so we decided to move to the next kinematic (SHMS theta = 7.74 deg) although just 80% of the 25K desired were taken at SHMS theta = 10.74 deg. 
When beam was restored around 6:40 pm we started taking data with SHMS theta at 7.74 deg. We settled on 35 muA which gave a ~680 kHz 3/4 rate in SHMS, ~ 15 % dead time and at least 85% tracking efficiency. 
Over night we lost beam again for about 2.5 hours due to power supplies issues somewhere in the injector.

As of now we took about 50% of the 21 K desired with SHMS thetaat 7.74 deg. 

We are now starting a beam energy measurement which should take about 2 hours and then we will resume physics data taking with SHMS at theta = 7.74 deg. We also plan to go back to SHMS theta  = 10.74 deg to take the remaining 5 K if there is time before 7 am tomorrow. We defer the luminosity scans to a later time so we can reach the 43% goal of the minimum statistical goal at the kinematic setting Q2 = 2.115, W = 2.95, x = 0.21, high epsilon.

Here is a link to the summary of the physics data taking so far: https://hallcweb.jlab.org/wiki/index.php/Kaon_LT_Status_Page

Tomorrow morning at 7 am Radcon will come to survey the hall so we can proceed with the SHMS aerogel tray change in preparation for data taking at the next kinematic setting: Q2 = 4.4, W = 2.74, x = 0.4, high epsilon. 

We will meet today at 4:30 pm on the second floor of the counting house.

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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/3604013
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