Agilent Technologies 5975 Series Operating Manual page 101

4 Operating in EI Mode
The largest influence on operating pressure in EI mode is the carrier gas
(column) flow.
flows. These pressures are approximate and will vary from instrument to
instrument by as much as 30%.
Table 14 Ion vacuum gauge reading


Column flow
rate, mL/min
0.5
0.7
1
1.2
2
3
4
6
If the pressure is consistently higher than those listed, refer to the online help in
the Data Acquisition software for information on troubleshooting air leaks and
other vacuum problems.
The vacuum can also be read on the 7890B GC control panel or from the Manual
Tune > Parameters view in OpenLAB.
5975/5977 Series MSD Operating Manual
Table 14 lists typical pressures for various helium carrier gas
Optional Gauge
reading, Torr
Performance turbo
pump
3.18E–06
4.42E–06
6.26E–06
7.33E–06
1.24E–05
1.86E–05
2.48E–05
3.75E–05
 

Foreline reading,
Gauge reading, Torr mTorr
Diffusion pump Diffusion pump
2.18E–05 34.7
2.59E–05 39.4
3.66E–05 52.86
4.46E–05 60.866
7.33E–05 91.784
1.13E–04 125.76
101