Development of a microcontroller based monitor for measurement of tritium in heavy water

A microcontroller based instrument for measurement of tritium in heavy water at concentration equal to or more than hundred milli-curie per litre is described. The tritium monitor has been designed using plastic scintillation film in a perspex cell and two photomultiplier tubes (PMTs) working in coincidence mode. The scintillation cell with coincidence electronics has a discrimination capability and enables to detect tritium in the presence of external gamma radiation. The monitor characteristics measured with tritiated water are presented. Sensitivity of the system is ∼ 460 CPS/Ci/litre under normal background level of 10-20 μR/hr. (author)