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

Ion Gun trouble

Doing Auger alignment tests on Cu110 single crystal. Lots of carbon, system has been baked, maybe vented, since sample was clean. 64 V LVV peak hard to see.

Manifold

• Ar sample cylinder open, Ar supply valve open, manifold pumping disconnected. This was done when bypass valve connected to air lock pumping some months back.
• Ar supply probably contaminated, maybe missing, i.e. air not Ar
• Disconnect bypass 2.75" VCR flange, add 2.75" tee, reconnect bypass and manifold pump. 
• Turbo pumps down to low 1e-5 in airlock, 14 W turbo, at least no major leak
• Reconnect Ar cylinder/regulator. 
• manifold arrangement bad, no way to isolate Ar supply, need to fix

Electronics

• Electronics start up, software connects, gun to standby, initially ~ 11 mPa, pumps down to zero in ~ hour or less (did not watch)
• Analysis chamber 1.3e-10, after FIG5 pump running a while, ionizer degassed, to 6e-11
• Pressure controller stuck at current limit with software running
• verify cables connected
• verify voltage from ~ 10x10x4 cm USB DAC box on top of 3com switch, voltage 2 V for 20 mPa, etc.
• check output pressure ref from 20-066. Stuck at 10 V, so no pressure control.
• Switch gun briefly from standby to run and back. Now pressure reference works!
• Problem seems to be emission current. Controller cannot maintain 25 mA. 
• Could be result of filament O2 exposure. 
• Can get 20 mA by increasing grid to 180 V from 150 V (range is 120 to 200)
• When emission current out of "green" range, pressure ref goes to 10 V. This may be "fail safe" design...
• Open leak valve 2 full turns, pressure to 4.2 mPa, 
• supply ~ 1 bar relative (regulator), 2 bar absolute
• 2.25 turns, now 33 mPa before controller regulates
• Electronics "click", relay like sound, no clear reason why, its always done this, seems to be associated with cut in ion current.

Test

• 30 degree tilt near center of Cu110 large hole sample holder, excellent auger down to ~ 40 eV. 
• sputter 20 mA "20 mPa" 3 kV 30 sec raster 1x1
• old "scan squares are gone
• Cl peak 180 gone, also O, C reduced
• Cu MVV clear, double peak
• after 6 min C gone