A radially dependent photopeak efficiency model for Si(Li) detectors

Measurements of M and L X-ray energies and relative intensities emanating from 241Am source

Energies and relative Intensities of 13 X-ray transitions in the M X-ray spectrum (per 100 disintegrations of ²⁴¹Am) viz. M₄N₁, Mξ_1,2, M₃N₁, Mα, Mβ, Mγ, M₂N₁, M₃O_4,5+M₃P₁, M₃Q₁, M₁N₃, M₂N₄+M₁N₃, M₂O₁ and M₁O_2,3 lines along with L₁-L₃ have been measured in addition to the 21L X-ray lines viz. Lℓ, Lt, Ls, Lα₂, Lα₁, Lη, Lβ₆, Lβ_2,15, Lβ₄, Lβ_5,7, Lβ₁, Lβ₃, Lβ_9,10, Lγ₅, Lγ₁, Lγ_2,8, Lγ_3,6, Lγ_4,4, Lγ₁₃ including two new lines at 19.63 and 23.17keV, have been measured. Since the M and L X-ray lines of ₉₃Np in the decay of ²⁴¹Am source are frequently used for energy and efficiency calibration of the Si(Li)/HpGe detectors, the present measurements have been undertaken with an objective to update the data since there are either no concrete data available (even in the Table of Radioactive Isotopes and Table of Radionuclides) or there exist inconsistencies/disparities in the data available in the earlier publications. We confirm the existence of L₁-L₃ X-ray transition (falling in the region of M X-ray energy range) and Lt, Ls and Lβ_9,10 (forbidden transitions as per selection rules). However, the origin of the two new L X-ray lines at 19.63 and 23.17keV, both with intensities of 0.05±0.01%, could not be ascertained.

Low-level activity measurement of 131Xem, 133Xem, 135Xe and 133Xe in atmospheric air samples using high-resolution dual X–γ spectrometry

High-resolution dual X and gamma spectrometry has been optimized to improve the sensitivity in analyzing radioxenon from environmental samples, especially for the metastable isotopes (131Xem and 133Xem). The full-energy peak (FEP) efficiency curve in the 20-700 keV range has been established with a global uncertainty better than +/-3% using a Monte Carlo simulation. The minimum detectable activity concentrations (MDC) achievable at the laboratory for 131Xem, 133Xem, 133Xe and 135Xe are presented and the influence of 133Xe activity on the metastable radioxenon MDCs is evaluated.

Calculation of emission probabilities of X-rays and Auger electrons emitted in radioactive disintegration processes

A complete set of data for the decay scheme of a radionuclide requires knowledge of the emission probabilities of X-rays and Auger electrons. If adopted sets of transition probabilities for the transitions of the decay scheme and atomic shell data (such as fluorescence yields and relative emission probabilities) are available, the emission probabilities of the X-rays and Auger electrons can be calculated from these data. Only data calculated in this way are consistent with the adopted input data and can be compared with measured data. Conclusions can be drawn with respect to the internal consistency of the data sets by comparing the measured and calculated data. Hence, the EMISSION program has been developed and tested to calculate X-ray and Auger electron emission probabilities along with their error propagation.