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CMS Pixel Detector
Miscellaneous
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Phase 1
Phase 2
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Layer 1 Replacement
Layers 2-4
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| Layer 1 Replacement Elog |
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Message ID: 67
Entry time: Thu Feb 6 00:45:25 2020
Reply to this: 70
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| Author: |
Dinko Ferencek |
| Category: |
Cold box tests |
| Subject: |
Lost at least one Peltier in the coldbox |
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During an overnight (Feb. 4-5) FullQualification run with modules 1545, 1547, 1548, and 1549 the coldbox lost the ability to maintain the temperature at -20 C. As can be seen from the attached temperature log, the problems already started during the temperature cycles where the last 2 cycles were noticeably longer than the first 3 and finally during the second Fulltests at -20 C the temperature started rising and stabilized around -10 C. Based on these observations it looked like at least one Peltier stopped working.
Silvan took apart the coldbox and will install new Peltiers. Based on measurements Andrey did with the old Peltiers it indeed looks like one Peltier stopped working but the remaining 3 also appear to be at different stages of degradation. |
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