[Hallc_running] [Revised Logentry] Status update

mack at jlab.org mack at jlab.org
Tue Feb 20 09:45:01 EST 2018

Logentry Text:
 RF recovery coincided with work on HMS Q1 and Q2 power supplies. While down, an access was made to improve temperature control for bcm1,2 by replacing the solid state relay.  With beam back, an HMS saturation test was completed. The inclusive physics program then restarted. Big niteshift! There was trip free beam at 50 muA for a while overnite. https://logbooks.jlab.org/entry/3534889 There were repeated problems with oscillation of HMS DCs. The HMS DC thresholds were raised to 5.5V (done by Jmenu) in the hope this will mitigate the problem while still providing a good tracking efficiency. Beam trips reportedly came back later. Why so soon after an RF recovery? Apparently there's an unexpected extra 100W or so of heat load in the linacs. They're looking for it. The PD is very interested in our maximum current, since Hall C's RF power load is the tail that wags the accelerator. I recommend staying at 50 muA, but we can discuss it at today's meeting.     

Sign up for shifts this coming weekend, etc.  Keep Eric P happy!

Special notices in effect for shift crews:
Instructions for LH2 <--> LD2 switches by TO : https://logbooks.jlab.org/entry/3534487
We are now operating HMS DC thresholds at 5.5V   https://logbooks.jlab.org/entry/3534955

Possibly flakey solid state relay for BCM1/Unser/BCM2 oven replaced:  https://logbooks.jlab.org/entry/3534470
cascade problems associated with the solid state relay replacement (Good Dave G catch. Never forget that even paranoids have enemies.):  https://logbooks.jlab.org/entry/3534564
HMS Q1, Q2 work: https://logbooks.jlab.org/entry/3535092  

Recent calibration/analysis updates:
Q2 = 11.5 Data quality check: https://logbooks.jlab.org/entry/3534429
Updated t-to-d maps for the SHMS :  https://logbooks.jlab.org/entry/3534419  (begs question of what about the HMS during CT)

We will meet in 200C at 1:30 pm (second floor of the counting house).

Link: https://bluejeans.com/543903672
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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/3535105
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