Installation manual

Operating in Electron Impact (EI) Mode 3
5975 Series MSD Operation Manual 65
Unless you have just begun the pumpdown process, the foreline pressure
should be less than 300 mTorr, or the turbo pump should be running at least
80% speed. MSD heaters remain off as long as the diffusion pump is cold or the
turbo pump is operating at less than 80%. Normally, the foreline pressure will
be below 100 mTorr, or the turbo pump speed will be at 100%.
The MSD heaters turn on at the end of the pumpdown cycle and turn off at the
beginning of the vent cycle. The reported setpoints will not change during
venting or pumpdown, even though both the MSD zones are turned off.