While looking at the ETMX for it's rubbing issue of late, we have been doing some data mining to understand why the ETMx Main and Reaction chain vertical BOSEMs (M0 and R0 LF and RT) are not where I would have assumed to leave them when we installed the "new" ETM test mass and rebuilt the suspension in 2018. Today, these vertical sensors are all ~6-8k counts when they should be closer to 11k per the open light voltage counts we determined in 2018 alog 41937.
I worried about temp and slow drift which could be also contributing to the rubbing, but in fact, it seems like something happened immediately at closeout in 2018 that put these vertical sensors off the nominal centered 11k value. (sigh)
In the end, hunting for an event or evolution which could have lead to the L1 LL rubbing of late has not been fruitful.
Anywho, since I waded through the deep water of everything-ETMX-SUS via temp change hunts, etc, I will post it here for the next time we wonder about what the longer history of the EX VEA temp has been doing:
Dec 2014 - CR excursions turned back down from 68 to 65
Jan 6, 2015 - 15883 - John turns temp “back to 65F (down from 67F)” - likely after a vent?
2015-2016 - No one writes actual temp values just things like “seasonal change so I turned a heater on”
May 2017 - 36271 - Upgrade to HVAC controls everywhere, EX week of ~May 15-18th, Kissel alog on calibration discrepancy 64 is actually 68…
May 22, 2017 - 36331 - Jeff/Bubba request to increase from 64 to 66 degC
May 30, 2017 - 36536 - Bubba changes which sensors are in-loop at EX
June 14, 2017 - 36894 - Bubba changes which sensors are in-loop at EX
Jan 23, 2018 - 40233 - Bubba/Hugh banter about where sensors in EX are mounted
Feb-Jun 2018 - Vented, warm with Cleanrooms on, new ETM/AERM installed
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June 1, 2018 - 42283 - Chamber closeout TFs ETMx
Vertical sensors get “bumped” or set from nom 11k to ~8k somehow.
June 6, 2018 - 42351 - Bubba puts temp back down to 65degF after chamber closeout
June 26, 2018 - 42664, 42686 - Chandra asks to put temp up to 68defF to aid in outgassing/pumpdown, Kissel/Chandra banter about temp increase. Chandra states that 65degF is more energy efficient than 68degF
June 29, 2018 - 42722 - Bubba puts temp back down to 65degF
Jan 27, 2022 - 61472 - Bubba/Fil move some sensors/cables, “The temperature at the end stations by request of Jeff Kissel several years ago was maintained at 65 degrees F.” - Probably need to go back to fact check this since originally Kissel suggested 66 per logs found above. 0.5degF change but Vert’s see -2k OLV change, weird.
Mar16 ’23-Jun 22 - EX "Rubbing" and 11Hz issues, offsets put on, then later turned off because not an issue “anymore” (68034, 68121, 63766) - So, in hind sight, could have had the L1 LL flag close and maybe brushing in 2022 then it kinda alleviated itself.
Aug 28, 2023 - 72497 - Kissel nice blog analysis of temp on EY, FWIW
Sept 14-15, 2026 - Rubbing issues on ETMX - L1 LL flag brushing. Vented, moved LL BOSEM over away from flag. See that ETM M0/R0 V BOSEMs have been at ~6-8k instead of nominal ~15k for many many many years (SUS is “UP” which correlates to “COLD”).
Sept 15, 2026 - 91912 - Richard raising EX from 65F to 67F as read out by HVAC chans. (This should drop the suspension and more center the V BOSEMs, but likely not an actual problem.)
