Determination of barium content in ground water by nondestructive neutron activation method

The technique for instrumental neutron activation determination of barium microquantities in ground waters is described. The water sample (0.3-0.5 l) is evaporated in sand bath at approximately 95 deg C, dry residual is packed in silver foil, it is soldered with standards in a quartz ampule and irradiated during 20 hours in 1.1013 n/cm2xs thermal neutron flux and it is hold during 10-15 days for decay of interfering radioisotopes Na24, K42, Cl38. Then the sample is repacked and B133 and Ba131 activities are measured (Tsub(1/2)=10.7 years and 11.5 days respectively) according to 356 and 496 keV gamma-peaks respectively by means of gamma spectrometer with 60-cm3 Ge(Li)-detector. The sensitivity of barium determination is nx10-9 g/ml, relative mean-square error is 10-18%. The efficiency of the method constitutes 20-25 samples per 6-hour working day in calculation for one analyst without account of radiation interval and holding after radiation