RGA laptop passcode: tw%11&STA-   

RGA scans set up and plotting data as of 11:44

RGA is set to the multiplier mode (4.44e-8mbar) with an accuracy setting of 8, these are for the most sensitive scans. RGA is set to scan masses 2, 12, 16, 18, 28, 32, 40 and 44 in the range 1e-9 to 1e-14mbar. Mass2=7.85e-11mbar,  Mass12=1.45e-12mbar,  Mass16=1.41e-11mbar,  Mass18=4.78e-10mbar,  Mass28=1.53e-11mbar,  Mass32=3.46e-12mbar,  Mass40 = 1e-14mbar,  Mass44= 3e-13mbar. Slight variability in each measurement is ver small for higher pressures and larger for lower pressures (see image attached). 

Plan is to switch each ion pump off individually and observe the effect on the RGA scans. Once off I will leave for 30 mins to see if any difference can be seen. Afterwards I will switch of 2 pumps then 4 pumps at a time. 

12:06 Ion pump 1 (furthest left pump=1, furthest right=4) turned off, no immediate change in RGA.

12:38 No change in RGA, turning pump 1 on again and switching off pump 2. Pump 1 took ~15s to stabilise back to a pressure of <8.9e-12mbar once turned on again. 

13:08 No change in RGA, turning pump 2 on again and switching off pump 3. Pump 2 took ~15s to stabilise back to a pressure of <8.9e-12mbar.  

13:38 No change  in RGA, turning pump 3 on again and switching off pump 4. Pump 2 took ~15s to stabilise back to a pressure of <8.9e-12mbar.  

14:08 No change in RGA, all pumps back ON. RGA has not changed since pumps wer switched off and on, pressure on the hot cathode gauge has risen slightly however I think this is due to the day/night cycle of the pressure. 

14:12 All 4 ion pumps turned off

15:12 No observable change in the RGA

15:33 Ion pumps all back ON. No change in RGA