[Primexd] [New Logentry] Follow-up Re: Suspicious channel in the inner FCAL ring

[gleasonc at jlab.org]

Logentry Text:
--
Here are some plots showing the voltage, current draw, and temperature of 4 different FCAL bases as a function of time. These channels were ranked by the number of times a base returned a HV reading that was at least 100V less than its set point. These variables were sampled from March 1st at 00:00 to March 3rd (today) at 17:00. Each data point is a reading of the EPICS variable every 30 minutes. So the first point shows the value at 00:00, the second at 00:30, third at 01:00, and so on. 

The suspicious channel, (1,2), had unstable HV beginning late Friday night and continuing through Saturday. It was dead for most of Saturday afternoon. If you look at the FCAL Occupancy plot on plot browser you can see three runs Saturday afternoon that show the hole in the occupancy. Since some time since late Saturday night, the base in question returned to being stable. Its current is still fluctuating, but this is okay as long as the HV has been stable. 5-6mA is a higher than the normal operating current of 3.5-4mA.

For now, it looks like one channel is completely dead (21,19). The others flagged appear to be stable. 

---

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/3662561
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mailman.jlab.org/pipermail/primexd/attachments/20190303/49cde145/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: application-pdf.png
Type: image/png
Size: 346 bytes
Desc: not available
URL: <https://mailman.jlab.org/pipermail/primexd/attachments/20190303/49cde145/attachment.png>