A leak detection using hydrogen as tracer gas

The device (1) has a hydrogen sensor (2) placed in low pressure enclosure (6) comprising diode, resistor and metal oxide semiconductor transistor whose gate is covered with palladium catalyst. A pumping unit (7) is connected to the enclosure, and a pressure gauge (9) i.e. manometer, measures pressure in a vacuum line formed by the enclosure. A multipath valve (4) includes a path to allow admission of gas stream containing tracer gas in the line and another path to allow admission of neutral gas. The latter path controls the pressure of the line based on the gauge. An independent claim is also included for a method for detecting leakages of object to be tested using hydrogen as tracer gas.