Prep for Gain Tests: Some Progress, Some Setbacks TKH for the Stony Brook Crew.
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Transcript of Prep for Gain Tests: Some Progress, Some Setbacks TKH for the Stony Brook Crew.
![Page 1: Prep for Gain Tests: Some Progress, Some Setbacks TKH for the Stony Brook Crew.](https://reader035.fdocuments.in/reader035/viewer/2022070403/56649f295503460f94c42311/html5/thumbnails/1.jpg)
Prep for Gain Tests:Some Progress, Some Setbacks
TKH for the Stony Brook Crew
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Box Preparation: Vacuum & Source
Some trouble with mis-manufactured LEMOs: Did not seat flush to surface. Leaked badly. ~1/3 of the LEMO connectors did not have full
threads up the body…bottomed out before sealing.
Stony Brook Shop Counter-bores holes. Leaks gone (w/ He leak Checker) Source mounted using battery clip.
Was 10 mCi 55Fe Now 2 ½ lives later…
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Box Preparation: Pad Plane & Gas
Small mods: Pad plane initially sized for prototype GEMs Holes put into it for final sized GEMs Solder pads interfere with final GEM frames.
Solution: Solder underside Raise pad plane.
Done and ready. Gas/pump:
Done
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DAMMIT!!!
On Saturday, while heat-shrinking tubing onto HV divider chain, DISASTER: Heat Gun and Scroll pump on same breaker. Breaker trips. Chamber under vacuum “refills” though pump
exhaust line (i.e. from the floor outside of tent) GEMs/Grid in use have lots of dust on them “Necessity is the Mother of Invention”:
Need GEM cleaning procedure to recover these GEMs for test use…maybe success??
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Step-by-Step Cleaning Tests
Look at GEMs under low (magnifying visor) and high (microscope) magnification: LOTS of dust (particularly top GEM).
Blow off with Bottle Gas: Removes ~90% of dust Not close to good enough.
Normal cleaning not good enough: Wash with flow of deionized water. Chase with ethanol. Blow dry with bottle gas. Little improvement…GEM looks bad.
UltraSonics!!
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UltraSonic Equipment from DCH Pulled out equipment from storage. UltraSonics in warmed deionized water bath:
40 kHz, 70 kHz, 104 kHz, 170 kHz Rough Cleaning Fine cleaning. Continual resistivity measurement
Tested one corner of one GEM dipped into UltraSonic bath: US-off…swish around: no change dust remains. US-on (40 kHz), “untouchable” dust gone in 30 sec.
Put whole GEM in tank: 10 min at 40 kHz. 1 min each at 70, 104, 170 kHz.
Quick look: GEM looks pretty good Used microscope on 1 strip…zero dust. Resistors look really clean and pretty.
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Lessons Learned:
Scroll Pumps Leak when off! Need electric gate valve. Exhaust flapper (like on main chamber pump)
MAYBE (learn today) UltraSonic cleaning can successfully remove dust from a dirty GEM. 1 strip from bad looking to looking perfect. Good to know if there is a way. Better to learn now than later.
Test one GEM for voltage holding before touching others I’m encouraged But keep your fingers crossed…