Leak detection device using hydrogen as tracer gas

A device for leak detection by means of hydrogen as a tracer gas, which device is intended to be connected to an object to be tested and comprises

• a hydrogen sensor placed in a low-pressure enclosure and comprising:
• a diode,
• a resistor and
• a MOS-type transistor whose gate is covered with a palladium catalyst,
• a pump connected to the low-pressure enclosure,
• a pressure gauge configured to measure the pressure in a vacuum line formed by the low-pressure enclosure connected to the pump,
• a multiway valve comprising a first port allowing admission of a gas flow containing the tracer gas into the vacuum line, and a second port allowing the admission of neutral gas,
• wherein the second port is configured to control the pressure in the vacuum line and said enclosure, as a function of the pressure gauge by controlling the admission of a neutral gas into the vacuum line through said second port;
• and wherein said leak detection device further comprises a circuit for balancing the voltage of the resistor of the hydrogen sensor, said circuit being configured to maintain a fixed temperature independently of the value of the pressure of the vacuum line, wherein said fixed temperature is between 100° C. and 250° C.