Rapid alpha spectroscopy of evaporated liquid residues for emergency response

A new method for alpha spectroscopy of evaporated water residues was developed, consisting of evaporation of drinking water, flaming of the planchets, and alpha-spectroscopic measurements using a grid ionization chamber. The method can identify and quantify radioactivity concentrations > or =3 mBq L-1 in a matter of several hours, whereas determination of sub-mBq L-1 levels is achievable in 1 day. Detailed investigations of flaming of the planchets, the humidity effect, and alpha spectroscopy of thick sources are described. A three-dimensional calibration of the method was performed using standards containing 238U, 230Th, 239Pu, 241Am, and 244Cm radionuclides. In addition to its application to evaporated drinking water, this calibration is common for any environmental sample that can be prepared as a uniform layer, such as the residues from surface water, acidic washing or leaching from materials, as well as biological fluids such as urine. The developed method serves as a fast identifying or screening technique for emergency response involving alpha radioactivity.