Patent ID: 8555704

Claim:
A tracer gas leak detector comprising: a test port configured to receive a test sample containing a tracer gas; a calibrated leak configured to provide a calibration sample containing the tracer gas; a mass filter coupled to the test port to receive the test sample in an operating mode, and coupled to the calibrated leak through a calibrated leak valve to receive the calibration sample in a calibration mode, the mass filter being controllable to vary transmission of the tracer gas through the mass filter and providing a filtered sample; a detector configured to detect the tracer gas in the filtered sample and to provide a detector signal; a programmable gain element configured to provide a measured value of leak rate in response to the detector signal; and a controller configured to operate the leak detector in the calibration mode in response to a mode control signal, and to calibrate the leak detector over two or more working ranges using the same calibrated leak, wherein, for each working range, the controller is configured to select the transmission of the tracer gas through the mass filter and the gain of the programmable gain element such that the measured value of the leak rate provided by the calibrated leak is within a same dynamic range of the controller.