Tritium measuring system in presence of gamma background

A detection and measuring system for tritium (gaseous or as tritiated water) and radioactive noble gases is presented, provided with a compensating system to extract the gamma background at the measuring position. The device is destined to radiation protection services in NPPs, laboratories and nuclear units working with tritium. The system consists of two identical ionization chambers and a compensation electrode. This compensation device is sufficiently sensitive to attain the void current of the ionization chamber system. The two chambers have equal volumes (10 l each) and are mounted on a base plate. Each of them consists of two coaxial cylinders of stainless austenitic steel which are voltage electrodes. The collector electrode passes through a high resistivity teflon piece. The compensating system consists of an additional electrode, fed at an appropriate voltage, allowing the correction for the gamma background up to 5 mR/h, accompanying the measuring process. The contaminated air sampling is ensured by a pump provided with a special filter retaining the aerosols and an electrostatic precipitator. The measuring tritium concentration range is 1.8 x 104 to 4 x 108 Bq/mc. The measure error is lower than 10%