chandra.romel@LIGO.ORG - posted 17:54, Wednesday 10 August 2016 - last comment - 10:34, Thursday 11 August 2016(29005)
HAM 6 pump down
Gerardo, Kyle, Chandra (and Bubba on doors) Started pumping down HAM 6 with rough pump at 5:10pm local. Kyle graciously offered to stay late until system can transition to turbo pump. Thursday morning Chandra will leak check the new gauge assembly. Crew can connect ISCT6 table first thing in the morning. If all is well with leak check, gate valves can be opened in the morning following leak check. Expect pump noise for over a week from maglev turbo on top of HAM 6 and 2-3 aux carts - pumping on annuli and one at vertex RGA (between HAM 4 & 5). Thank you Bubba for helping install doors today! We spotted a new nick on north door at 4 o'clock position in the path of the outer o-ring but leak checking confirmed there is no leak. We leak checked both north and south doors by pumping on the annulus volume. Dew point of chamber during blow down was -19.9 deg C. Gerardo & Kyle took some particle count measurements at south side after north door was sealed. They can report the #s. New wide range ion gauge was installed. Thanks Richard and Fil and others for running cables/power and rebooting for immediate monitoring!
Chandra rightly pointed out that the procedure we actually use when pumping HAM1 & HAM6 is sufficiently unique as to require their own distinct procedure (" I'll get right on that Chandrohn! ")Dust counts:
Took a reading before entering cleanroom with door, counts remained at 0, another reading with the door inside the cleanroom with counts still at 0. removed both covers (door and chamber) and took a third reading with 9 for 0.3 um and 4 for 0.5 um.