The k0-standardization method of neutron activation analysis (NAA) is very sensitive to the irradiation and counting time during measurement of the induced radionuclide by -spectrometry on the HP Ge detector. If the irradiation and counting time of the sample and co-irradiated standard is relatively short or the decay constant small, the application of the standard equation in the software for the specific count rate may become numerically unstable and the program aborts. In this work, attention is focused on the direct influence of saturation and "measurement" factors on the specific count rate for simple decay and for more complex types calculated directly by exponential functions, and by an alternative form using a truncated Taylor's series expression.
Results of recent IAEA activities related to assembly, maintenance and verification of databases of relevance to radiochemistry are presented. These include: (1) integral and differential nuclear constants for prompt gamma neutron activation analysis; (2) excitation functions for cyclotron production of medical radioisotopes using proton, deuteron and alpha particle projectiles; (3) data for dose calculations in radiation medical treatment/diagnosis and (4) nuclear cross section standards.
An experimental verification of Monte Carlo neutron flux calculations in typical irradiation channels in the TRIGA Mark II reactor at the Joef Stefan Institute is presented. It was found that the flux, as well as its spectral characteristics, depends rather strongly on the position of the irradiation channel. Comparison of the results for parameter f (thermal-to-epithermal flux ratio), experimentally obtained by the Cd ratio multi-monitor method and Monte Carlo simulations shows relatively good agreement for most studied configurations except for the channel IC40 in the carousel facility, where differences are relatively large and not understood.