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Task #1089
openHV Operation Test
Status:
New
Priority:
High
Assignee:
-
Start date:
05/22/2025
Due date:
% Done:
0%
Estimated time:
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Added by Sho Nagao 3 months ago. Updated 2 months ago.
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Email copy from Liguang
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We made further test on EDC. Without the UU' and VV' planes, EDC can steadily hold 2200 V with less than 1 nA current. There is at least one broken wire in each of the UU' and VV' plane groups (2nd and 4th layers according to EDC label). The broken wires shorten the HV to the ground through the protection resistor so that the current changes linearly with HV according to the Ohm's law. Broken wires in both these two groups are at the corners, i.e. at or near the end of the raw.
This appears similar to the spare KDC which has a broken wire on the U plane near the end of the raw. I do not know why the really short wire is easier to broke.
You need to make decision on how and when to fix the broken wires.
Conditioning the KDC's are harder since they are based on G10 PSB boards and have cathode foil planes. Material out gas can leave persisted residues on surfaces after 16 years in storage. Both KDC1 and KDC can hold 2000 V or higher but dark current is high. We will leave it that way and give them time to settle.
A group from University of Glasgow expressed interest in joining us and may have a Ph.D. student from our experiments. As the SBS program (the large group of experiments on the nucleon electric and magnetic form factors) in Hall A approaches to its end, there may be more groups which involved previously in Hall A or C willing to join us, of course, with different level of interests.