[Optimization of liquid scintillation counting by using multichannel pulse-height analyzer].

The method for determining optimum conditions of a liquid scintillation counter (LSC) for low-level counting of tritium was studied. To compare the lower limit of detection, the figure of merit EM/square root B was used. Th measurement system is a LSC connected with a multichannel pulse-height analyzer (MCA). Both of tritium spectra and background spectra were searched for the condition that maximizes the figure of merit. The optimum condition obtained by using the MCA was fitted for a single channel pulse-height analyzer of the LSC. The figure of merit obtained by this method was 20.6% greater than that obtained by the balance point method.