Absolute Gamma-ray Emission Probabilities Research Articles

Measurement of absolute gamma-ray emission probabilities from decay of 138Xe

The fission gaseous 138Xe products play an important role in the research of nuclear-reaction products and radioisotope applications. Therefore, precise data for emission probabilities of gamma-ray from decay of 138Xe are highly desired. However, a high precision is not achievable with a sufficient accuracy due to the limitations of the usual experimental techniques. In this paper, after the homogeneous sources of 138Xe–138Cs were prepared, the activity of 138Xe was obtained by the decay relationship between 138Xe and 138Cs using a HPGe detector. The full-energy peak efficiencies of gamma-ray for 138Xe and 138Cs were accurately calibrated using many activity standard sources and self-absorption was corrected. As a result, the absolute emission probabilities of the 258.4, 434.6 and 1768.3keV gamma-ray from decay of 138Xe were determined to be 34.9(10)%, 22.2(6)% and 18.8(5)%, respectively.

Beta decay of the fission product 125Sb and a new complete evaluation of absolute gamma ray transition intensities

The radionuclide 125Sb is a long-lived fission product, which decays to 125Te by negative beta emission with a half-life of 1008 day. The beta decay is followed by the emission of several gamma radiations, ranging from low to medium energy, that can suitably be used for high-resolution detector calibrations, decay heat calculations and in many other applications. In this work, the beta decay of 125Sb has been studied in detail. The complete published experimental data of relative gamma ray intensities in the beta decay of the radionuclide 125Sb has been compiled. The consistency analysis was performed and discrepancies found at several gamma ray energies. Evaluation of the discrepant data was carried out using Normalized Residual and RAJEVAL methods. The decay scheme balance was carried out using beta branching ratios, internal conversion coefficients, populating and depopulating gamma transitions to 125Te levels. The work has resulted in the consistent conversion factor equal to 29.59(13) %, and determined a new evaluated set of the absolute gamma ray emission probabilities. The work has also shown 22.99% of the delayed intensity fraction as outgoing from the 58 d isomeric 144keV energy level and 77.01% of the prompt intensity fraction reaching to the ground state from the other excited states. The results are discussed and compared with previous evaluations. The present work includes additional experimental data sets which were not included in the previous evaluations. A new set of recommended relative and absolute gamma ray emission probabilities is presented.

Experimental determination of absolute gamma-ray emission probabilities for 88Kr

Through preparation of the homogeneous sources for 88Kr and 88Rb, the activity of 88Kr was determined by the decay relationship between 88Kr and 88Rb using HPGe detector. The peak efficiencies of gamma-ray for 88Kr and 88Rb were accurately calibrated. As a result, the absolute gamma-ray probabilities of the 196.3, 834.8,1529.8,2195.8 and 2392.1 keV gamma rays for 88Kr were determined to be 25.1(5)%, 12.9(2)%,10.7(2)%,13.3(2)% and 34.9(5)%, respectively.

Measurements of absolute gamma-ray emission probabilities in the decay of 233Pa

Abstract Gamma-ray emission probabilities from the β − decay of 233 Pa were measured with planar (LEPS) and coaxial Ge detectors. A 233 Pa source was produced after radiochemical separation from a 237 Np sample in which the parent ( 237 Np) and daughter ( 233 Pa) nuclides were in secular equilibrium. Absolute γ ‐ ray emission probabilities per 100 α decays of the parent nuclide 237 Np were also measured in conjunction with the α - and γ ‐ ray spectroscopy techniques.

Evaluation of absolute gamma ray emission probabilities in the decay of [formula omitted

All previously known gamma-ray emission probabilities (absolute and relative) in the radioactive decay of 234 m Pa have been examined resulting in a new and more precise evaluation. Beta branching ratios and the calculated internal conversion coefficients and their uncertainties have been used to obtain complete and satisfactory decay intensity balance. A new decay scheme is proposed based on the present evaluation. It includes three new suggested energy levels and incorporates 14 measured gamma ray energies that were not placed in the decay scheme currently in adoption.

Standardisation of 125Sb and 154Eu, and measurement of absolute gamma-ray emission probabilities

A method has been devised to separate 125Sb from its short-lived daughter 125mTe. This technique was based on the repeated use of columns of anion exchange resin and supplemented by chemical procedures chosen to avoid any steps involving evaporation. which in initial trials gave severe problems due to the volatility of the antimony. Standardisation by 4πβ-γ coincidence counting was carried out within a few days of the separation, allowing for the daughter which grows in at about 0.25% per day. Beta counting efficiencies, as measured by the ratio of coincidence to gamma count rates, of up to 90% and 95% respectively were obtained for the two gamma-ray energy windows used. The ingrowth was monitored over a period of one month by gamma-ray spectrometry, using the weak 109 keV gamma-ray of 125mTe, to check the original separation.Samples of 154Eu were produced by neutron irradiation of high purity 153Eu, which was obtained by passing inactive europium through the NPL isotope separator. A solution of the 154Eu was standardised by coincidence counting, again using two gamma-ray energy windows, to give efficiencies of 96% and 98%.Absolute gamma-ray emission probabilities were measured for both nuclides using a germanium spectrometer calibrated with a range of nuclides of known activities and gamma-ray emissions. Sources were positioned 55 cm from the detector to ensure that real summing effects were negligible.

Decay scheme data for 154Eu, 198Au and 239Np

Measurements of relative and absolute gamma-ray emission probabilities in the decays of 154Eu, 198Au and 239Np are reported. For the first two radionuclides previously published conversion-electron and beta-branching data have been used with the gamma-ray data to formulate self-consistent decay schemes.

Gamma-ray emission probabilities in the decay of 65Ni and 125Sb

An evaluation has been carried out of previously published gamma-ray emission probabilities in the radioactive decay of 125Sb. Beta branching ratios and internal conversion coefficients have been taken into account in testing the consistency of the total decay scheme. Measurements have also been made of the absolute gamma-ray emission probabilities in 65Ni and 125Sb using a combination of high resolution gamma-ray spectroscopy and 4πβ-γ coincidence techniques