INFICON Sensistor ISH2000 Hydrogen Leak Detector - Manual (Page 7)

EN- 7 Sensistor ISH2000 Technical Reference Manual (TRM)
A 400
A 300 Sensor Technologies working principle
Sensor Technology
The Sensistor ISH2000 leak detector is using SENSISTOR sensor technology
inside. SENSISTOR sensor technology uses an extremely sensitive hydrogen gas
sensor based on a microelectronic field effect transistor (MOS-FET).
The gas sensitivity appears when hydrogen absorbs into the sensor through a
metal alloy (metal hydride) layer.
Only hydrogen can diffuse into the metal and this makes the sensors practically
insensitive to other substances that do not contain free hydrogen molecules.
The signals from the sensors are processed by a microprocessor which also con-
trols the sensor temperature with high accuracy, and other sensor diagnostics in
order to ensure perfect functionality. It also automatically compensates for
background gas.