keV Gamma Transition Research Articles

Energy levels of Te 125

The energy levels of Te 125 have been studied by detailed gamma gamma coincidence measurements. Two new weak gamma transitions of energies 80 ± 5 keV and 120 ± 5 keV have been observed in coincidence with the 176 keV gamma transition. A new energy level has been introduced at 401 keV. There is evidence of a weak gamma transition of 62 keV between levels at 524 keV and 462 keV.

Decay of Cd115(2.3d)

The decay of Cd115 (2.3d) has been studied by scintillation beta and gamma spectroscopy. The K-internal conversion coefficients of the 35 and 335 keV gamma transitions in the de-excitation of In115 have been measured to be 7.6±0.8 and 0.84±0.09, respectively. The β-γ coincidences showed that the 590 and 860 keV beta branchings may be of an allowed and ΔI = 2 unique forbidden types, respectively. From the angular correlation studies of the 35–492 keV and 230–262 keV cascades, 5−2, 3−2and1−2or3−2 may be assigned to the 597, 827 and 862 keV levels, respectively.

Structure of platinum nuclei (I) new decay scheme of Au 196

Nuclear structure of Pt 196 has been investigated from the decay of the 6.2 d Au 196. New weak gamma rays of 312, 444, 522, 568, 644, 757, 762 and 1090 keV were found in the analysis of conversion electron spectra by the use of a sector-type double focusing beta ray spectrometer. These new gamma rays were all coincident with the 356 keV gamma transition between the first and ground state of Pt 196. From the ratio of electron capture to positon emission rate ϵ K.L.M./ β + = 2.0±0.4 × 10 6, the electron capture decay energy of the 6.2 d Au 196 is estimated as 1480 −12 +8 keV. Directional correlation measurements of 1090-356, 760-340, 530-340 and 333-356 keV gamma ray cascades were also performed. The level scheme of Pt 196 is proposed as folows: 1446 keV, 3 −: (1316 keV, 3 +, 2 +): 1117 keV, 2 +; 1002 keV, 3 +: 877 keV, 4 +; 689 keV 2 +; 356 keV, 2 +. The 1446 keV 3 − state is assigned as the lowest octupole vibrational state. Almost all these levels are compared with ones determined from the measurement of the Pt 195(d, p)Pt 196 reaction. The large excitation of the 3 − state by the stripping process seem to be difficult to understand on the basis of any of the usual theories. The extremely low value of the 689 keV cross over transition from the second excited 2 + state, 689 K/356 K = 1.0±1.0 × 10 −5 is discussed in terms of intrinsic nucleonic excitations.

The negaton transition in 196Au

The end point energy of the negaton spectrum emitted by 6-d 196Au is measured to be 259±4 keV, as observed by measurements in coincidence with the following 426 keV gamma transition. For the half-life of 196Au, a value 6.07±0.11 d was found.

The decay of Lu 177 to Hf 177

The beta-decay of Lu 177 has been investigated and four beta-groups of maximum energies 496.8±1.7, 385±2, 249±4 and 174±3 keV were found. The relative intensities were determined as 90±4, 2.95±0.05, 0.31±0.06 and 6.72±0.25%, respectively. Beta-gamma coincidences have been recorded between the second beta-branch and the 113 keV gamma-ray; and between the fourth beta-branch and the 208 keV gamma-ray and the Kurie plots from the coincidence measurements showed maximum energies of 384±2 and 175±1.0 keV which are in good agreement with the results obtained from the gross spectrum. The coincidences found between the 250 keV and the beta-background confirmed the existence of a new beta-group with low intensity. The L-conversion coefficient of the 113 keV gamma-transition has been determined by the coincidence technique and the result obtained was 1.102±0.110. The mixing ratio δ 2 = E2/M1 of the 113 keV gamma-ray as determined from the measured L-conversion coefficient was found to be 27.0±2.7 using the theoretical conversion coefficients calculated by Rose and 17.0±1.7 when we used that calculated by Sliv and Band. The first value of δ 2 is in agreement with the results obtained by angular correlation measurements.

Decay ofSi26

A (2.1\ifmmode\pm\else\textpm\fi{}0.3)-sec activity was observed when vacuum distilled magnesium was bombarded with 8-Mev ${\mathrm{He}}^{3}$ ions. Half-life studies using NaI(Tl) scintillation counters yielded evidence that this activity was due to the decay of a positron emitting isotope with a maximum kinetic energy greater than 3.5 Mev. The features of gamma-ray spectrum with the exception of a weak line at 824\ifmmode\pm\else\textpm\fi{}15 kev could be understood in terms the decay characteristics of known radioisotopes. An internally consistent argument based on the known decay characteristics of reaction products that may be expected from energy considerations, the results of half-life studies, experimental gamma spectra, and nuclear systematics can be made to support the conclusion that the (2.1\ifmmode\pm\else\textpm\fi{}0.3)-sec half-life is that of ${\mathrm{Si}}^{26}$ produced in the reaction ${\mathrm{Mg}}^{24}({\mathrm{He}}^{3}, n){\mathrm{Si}}^{26}$, and a consistent decay scheme can be proposed. The ground state of ${\mathrm{Si}}^{26}$(0+) decays by the emission of two positron groups to excited states of ${\mathrm{Al}}^{26}$. The most intense transition, ${E}_{0}=3.76$ Mev, is to the 0.228-Mev state (0+) of ${\mathrm{Al}}^{26}$. The second transition, ${E}_{0}=2.94$ Mev, is to the 1.05-Mev state (1+) of ${\mathrm{Al}}^{26}$. The 1.05-Mev and 0.228-Mev states are then connected by a (824\ifmmode\pm\else\textpm\fi{}15)-kev gamma transition. The energies of the positron transitions are derived from the known levels of ${\mathrm{Al}}^{26}$ and the ${\mathrm{Si}}^{26}$-${\mathrm{Al}}^{26}$ mass difference.

Conversion coefficients of gamma transitions in 203Tl

Conversion coefficients in 203Tl are determined as α K = 0.163±0.003, α L = 0.0487±0.0012 for the 279.12 keV gamma transition, and α K = 0.118±0.011 for the 404 keV transition. These results are discussed in view of possible deviations from theoretical values for M1 and E2 conversion coefficients. The decay energy of 203Pb is estimated to be 950 −70 +300 keV.

Beta and gamma ray spectroscopy of Cs 137

Beta rays and internal conversion electrons from Cs 137 have been studied using a two directional focusing beta ray spectrometer ( ∂ = 40 cm). The K shell conversion coefficient α K of 661 keV gamma transition has been determineto be 0.0976±0.0055, and K/L/M to be (5.66±0.04)/1/(0.260±0.003), which are in good agreement with Rose's calculated values for the M4 transition. The maximum energy of the lower component of the beta rays has been found to be 514±2 keV. The Kurie plot, corrected by the factor of the unique first forbidden transition, shows a straight line. The spectrum of the higher component was interpreted by the second forbidden correction factor with a linear combination of scalar and tensor interactions. In an attempt to determine the sign of the ratio of scalar to tensor interaction constants, G s/ G T, the spectrum could be only explained by the negative sign, assuming that the single particle model is a good approximation for the nuclear matrix elements.

Decay of Gd 153

The decay by electron capture of Gd 153 (half-life 236 days) is studied with a coincidence Scintillation Spectrometer. Two gamma-rays are observed with energies 72±8 keV and 100±4 keV and relative intensities of 7 : 100. Both these gamma-rays are coincident with K X-rays of Eu. From the coincidence data the K-shell conversion coefficient of the 100 keV gamma transition has been determined to be 0.67±0.12; the comparison with theory then leads to assigning this gamma-ray predominantly to a magnetic dipole transition. From the experimental L/K capture ratio the energy involved in the capture process is estimated. Our results show that the levels in Eu 153 which are reached by the capture decay of Gd 153 are not identical with the levels that were observed in coulomb excitation of Eu. On the basis of our findings we propose a decay scheme for Gd 153.

Decay of Gd 153

The decay by electron capture of Gd 153 (half-life 236 days) is studied with a coincidence Scintillation Spectrometer. Two gamma-rays are observed with energies 72±8 keV and 100±4 keV and relative intensities of 7:100. Both these gamma-rays are coincident with K X-rays of Eu. From the coincidence data the K-shell conversion coefficient of the 100 keV gamma transition has been determined to be 0.67±0.12; the comparison with theory then leads to assigning this gamma-ray predominantly to a magnetic dipole transition. From the experimental L/K capture ratio the energy involved in the capture process is estimated. Our results show that the levels in Eu 153 which are reached by the capture decay of Gd 153 are not identical with the levels that were observed in coulomb excitation of Eu. On the basis of our findings we propose a decay scheme for Gd 153.