Intrinsically calibrated gamma and x-ray measurements of plutonium

Determination of the uranium enrichment without calibration standards using a 500 mm3 CdZnTe room temperature detector with a hybrid methodology based on peak ratios method and Monte Carlo counting efficiency simulations

“…Determination of the uranium enrichment without use of calibration standards implies that the counting efficiency curve is calibrated intrinsically by using the information from the measured spectrum. A method that allows for such an intrinsic calibration of the counting efficiency curve is known as the peak ratios method (Reilly et al, 1991;Dragnev, 1993), yielding the relative isotopic abundancies of the radionuclides considered in the analysis. In such a method fitting of an appropriate empirical or physics based counting efficiency model as a function of gamma-ray energy to a set of experimental data points is used to estimate the relative isotopic abundancies using the peak ratios at specified energies for the radionuclides considered in the analysis, as shown by Eq.…”

Uncertainty assessment in gamma spectrometric measurements of plutonium isotope ratios and age

“…One method is based on the analysis of peaks in the X-ray region around 100 keV [6]. Another method uses the more high energetic gamma rays emitted in the decay of the different plutonium isotopes [7].…”

Determination of the uranium enrichment without calibration standards using a 2 × 2 inch LaBr3(Ce) room temperature detector and Monte Carlo sampling approach for uncertainty assessment

“…Another method is based on measurements of gamma-ray signatures in the 143-1001 keV energy region only [11], the advantage of which is that it allows uranium bearing materials assay behind thicker shielding or packaging. The latter two methods are based on the computation of the isotopic ratios using a counting efficiency curve calibrated intrinsically for the determination of the uranium enrichment and plutonium isotopic composition [12,13]. For such methods calibration standards are not required and all the necessary information for the analysis is taken directly from the measured spectrum of a sample the enrichment of which or isotopic composition is not known in advance [11].…”