Experimental investigation of mass efficiency curve for alpha radioactivity counting using a gas-proportional detector

Gross α counting of evaporated water residues offers a simple method for screening α radioactivity in water for both public health and emergency purposes. The evaporation process for water has been improved by using a combination of roughening of the surface of counting planchettes, two-stage evaporation, and temperature-controlled block heating. The efficiency of the gas-proportional detector for α-particle detection in water residues was studied as a function of sample mass–thickness in the range between 0.1 and 13 mg cm−2. The effect of α energy on the efficiency, as well as moisture absorption on the samples, were studied using 230Th, 238U, 239Pu, 241Am, and 244Cm radionuclides. Also, α-to-β crosstalk was investigated as a function of sample mass for 230Th, 239Pu, 210Po, 241Am, and 244Cm. The improved method can also be applied for gross α detection in biological fluids.