Alpha detection using semiconductor silicon detectors immersed in a solution

The possible applications are briefly described of silicon semiconductor surface barrier detectors in measuring alpha activity in direct contact with the solution containing alpha activity. Findings are reported obtained in the measurement of integral alpha activity of the 239Pu-241Am mix in a 2M HNO3 solution using an immersion detector. A comparison is made with scintillation detector measurements of total solids on stainless disks. The results are also shown of the spectrometric measurement of the 233U + 239Pu + 241Am mixture of a known composition in 2M HNO3 using an immersion probe with a semiconductor detector 32 mm2 in area; the specific silicon resistance was 2 kΩcm, the detector operating voltage was 15 V. (B.S.)