[en] Experimental studies on the basic characteristics of IPs applied in γ-ray imaging are carried out by utilizing isotopic γ-ray sources. The 1.25 MeV γ-ray sensitivity of the BAS-MS and BAS-TR imaging plates and their enhanced sensitivity by covering appropriate Compton conversion foils are measured based on the studies of the image intensity linear calibration, time attenuation laws and the influence of scanning parameter settings. The energy-dependent γ-ray sensitivity of the IPs is also obtained by the studies of the measured sensitivity and the Monte Carlo simulated energy deposition in the IPs' sensitive layer. Furthermore, a method of a sandwich detection structure as well as its primary experimental validations are presented in order to increase the gamma-to-neutron ratio in a γ/n mixed radiation field. (authors)

[en] Sorption (distribution) coefficients of plutonium were most often derived by static batch experiments. However, it is not clear how unsaturated flow conditions including moisture content and pore water velocity change the sorption coefficients. Transport experiments of plutonium through the unsaturated sediments packed into the columns were then performed in order to determine the sorption coefficients (column-K_ds). Static batch experiments were also conducted to obtain batch-K_ds and then compare the differences between batch-K_ds and column-K_ds. The results show that unsaturated flow conditions had no significant effect on column-K_ds, and the average column-K d value was 1.74 ± 0.02 m³/kg. By comparison, batch-K_d values spanned several orders of magnitude, regardless of the specified liquid-solid conditions. Moreover, the batch-K_d (22.7 m³/kg) at the standard L/S (4 mL/g) recommended by ASTM D 4319 was over an order of magnitude larger than the average column-K_d. (author)