Nuclide identification for pure beta-emitting radionuclides with very similar beta end-point energies using a liquid scintillation spectrometer

Identification of Pure Beta Nuclides with Very Near Maximum Energies Using a GM Counter and Thin Absorbers

“…source.Error bars designate 3 a.The values of Y were larger than 0.9y,and smaller than 1.1 ys.Every Y-3a was larger than 1.1yc.All attenuation rates at Lo-L4 satisfied the equation (5).The 150 Bq 35S was discriminated from 14C by measuring attenuation rates at Lo without absorber and at L,(i = 1-4)with absorber. Figure 5 shows the relationships between the lowest identifiable activity(LIA)and the measurement time when BG was measured for 300 min.When the absorber Al was used,the LIA of 14C decreased from 450 to 24 Bq as the measurement time increased from 1 to 50 min.The LIAs of 14C and 35S were less than the legal limit of 40 Bq in the controlled area when the samples were measured for 20 min or longer.Contrastingly,when absorber A4 was used,the LIAs were greater than the legal surface density limit up to 50 min.The thinner absorbers gave smaller LIAs.The 35S LIAs were lower than 14C except for a 3 min measurement with absorber A. and the difference between the ratios decreases considerably.…”