Mass Filter; Pressure Set Point; System Pressure - Thermo Scientific Prima PRO User Manual

Status & Tuning Parameters
Analyser Tab

Mass Filter

Pressure Set

System Pressure

8-6 Prima PRO & Sentinel PRO Mass Spectrometers User Guide
Status
Magnet temp busy
Magnet failure
Magnet pulse busy
Magnet field init busy
The approximate magnetic field setting, in Tesla, is indicated by the
Mass Filter parameter. The value for Mass 28 with 1000 V ion
energy is typically 0.4 Tesla.
The relationship between mass and magnetic field and ion energy is
given by:
A four times increase in magnetic field strength therefore doubles the
mass detected.
At pressures above the value set in the Pressure Set Point parameter,
Point power is removed from the filament supply, source heater, SEM
supply, and source high voltage supplies to protect the analyser from
damage which may result if run at high pressure.
The System Pressure value indicates the pressure as reported by a
Penning vacuum gauge head that is mounted on the top right of the
vacuum chamber and is a measure of the high vacuum produced by
the turbo molecular pump.
The pressure, as measured by the Penning gauge, is a combination of
the amount of sample gas leaking into the chamber via the capillary /
leak arrangement and gas that 'evolves' from the internal surfaces of
the vacuum system. This is known as out-gassing.
When the inlet is blocked, the vacuum falls to its background level,
which is usually in the region of 10
the operating vacuum should be in the region of 1 - 10 x 10
This varies slightly from instrument to instrument and on the gas
being sampled.
The upper limit of pressure that can be displayed by the Penning
gauge is about 1 x 10
that the pressure may be too high to be measured by the gauge and
that there is either a significant system leak or a pumping fault.
Check that the turbo molecular pump is up to speed (indicated as
Turbo Revs on the Instrument Status window). Check that the rotary
pump is functioning correctly.
Value
8
9
10
11
Mass  (magnetic field)
-7
-2
mbar. A stable reading at this level indicates
Measuring the magnet
temperature.
Controller or circuit failure.
Busy driving the magnet.
Initialising the system (about 60
s)
2
/ion energy
mbar. When the inlet is open,
Thermo Fisher Scientific
-6
mbar.