Vacuum problems during sample intro
- Granville phillips micro ion gauge controller shows 2e-5 air lock pressure
- degass gauge, jiggle connector cable, no help
- Leave pump running ~ 1.5 hour during sample transfer, analysis, then open gate valve
- prep still 8.8e-6, would expect better
- prep chamber 1.8e-7 (low 10's before opening), consistent with intro gauge
- close gate, pressure drops low 9's prep, increase to 1.7e-5
- Connect VQM cable to prep mass spec, turn on, mostly 18 amu in UHV
- open to air lock, lots of 32, 28, leak...
- pump air lock with prep ion pump, turbo valved off
- now mini IG 4.6e-7, prep 3.8e-8
- close valve to air lock, 14 and 28 drop, 18, 2, 44 relative rise, 1.9e-9
- reopen gate
- prep back to 3.8e-8
- 28, 14, 40, 32 rise, water related peaks fall
- now open turbo pumping valve
- pressure to 2.4e-7 prep, 9.8e-6
- 28, 32, 14 rise, also 40, air leak
- close turbo valve, pressure drops, 5e7 in air lock, 4.6e-8 prep, 14, 28, 32, 40 drop
- even with turbo valve closed, air lock pressure rises rapidly from mid 7's to 5's
Air leak in pumping, probably in manifold
- biggest leak was swagelock connected to mini flange at manifold pumping valve, tighten to reduce manifold to 1.1e-6 from 2e-5.
- gasket (already suspicious) at 2.75" tee caught between flanges, ie offcenter, replaced.
- marginal improvement, still possible leak in manifold somewhere
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