RGA data from HAM 3:

Attached plots are:

HAM3 RGA only - RGA prior to opening any valves to the system - this is "as found" after starting the 2l/s ion pump on the RGA tree after moving from ENDY to the LVEA.

HAM3 RGA + T - Kyle and I installed a T fitting beween the RGA and the 10inch gate valve so that we could evacuate the "dead space" prior to opening to HAM3. This required opening the all metal 1.5 inch valve on the RGA tree.

HAM3 RGAall - this is with the RGa open to HAM3  - ie the 10inch gate valve was opened. The total pressure at HAM3 is estimated at  3 e-8 torr.

From the plot HAM3 RGAall the relative ion currents and partial pressures for some amus are:

amu 2 - 1 e-9 amps   ~5e-9 torr

amu 18 - 3e-10         ~9e-9 torr

amu 28 - 2e-10         ~ 6e-9 torr

amu 41 - 1.8e-12       ~ 5e-11 torr     corrected these values x10^-1

amu 51 - 1e-12          ~3e-11 torr

amu 69 - 5e-13          ~1.5e-11 torr

Assume that the total pressure = 0.5x amu2 + amu18 + amu28 you get a calibration of 1 amp = 30 torr.

For all these measurements the small 2l/s ion pump registered 3.8 mvolts or 0.038 milliamps ion current.

I am uncertain of the SEM voltage in these scans as the software appears to let me change the voltage and yet the plots look identical.

Note that the calibration gas of the RGA tree appears to be open to the system but it is not - the Nupro valve has been damaged and no longer seals completely.