3 - 3
Transpector XPR 3+ Operating Manual
3.4 Sensor
The Transpector XPR 3+ sensor (see
) analyzes gases by ionizing some
of the gas molecules (in the ion source), separating the ions by mass (in the mass
filter), and measuring the quantity of ions at each mass (in the detector). The
masses, unique for each substance, identify the gas molecules from which the ions
were created. The magnitudes of these signals are used to determine the partial
pressures (amounts) of the respective gases.
The Sensor consists of three main parts:
ion source (ionizer)
quadrupole mass filter
ion detector
All of these parts are mounted on an electrical feed-through flange, which is bolted
to the vacuum chamber where the gas analysis measurements are made.
The sensor works only in a high-vacuum environment because the ions, once
created, must not collide with other gas molecules as they move through the
sensor; otherwise, they might not be detected. The miniature design of
Transpector XPR 3+ allows it to operate at pressures higher than those necessary
for traditional RGA sensors.