THE DECAY OF Re186 AND Re188

1956 ◽  
Vol 34 (1) ◽  
pp. 69-82 ◽  
Author(s):  
M. W. Johns ◽  
C. C. McMullen ◽  
I. R. Williams ◽  
S. V. Nablo
Keyword(s):  
High Resolution ◽  
Gamma Rays ◽  
Decay Scheme ◽  
Low Energy ◽  
End Points ◽  
Coincidence Measurements ◽  
Good Agreement

The energies and intensities of 13 gamma rays in Re188 have been measured by studying their external conversion spectra with a high resolution beta-ray spectrometer. An analysis of the beta-ray spectrum reveals groups with end points 2116 kev. (79%) and 1961 kev. (20%), and several low energy groups whose total intensity is of the order of 1%. The observed data can be consistently accounted for in terms of a decay scheme involving the following levels of OS188: 0.0, 155.0, 633, 1086, 1306, 1461, 1765, 1941, and 1958 kev. This scheme is firmly supported by coincidence measurements. The spins of the first three levels listed are 0+, 2+, and 2+ and that of the 1461 kev. level is probably 0+.The decay of Re186 is accompanied by gamma rays of the following energies and quantum intensities: 122.9 kev. (0.6%), 137.2 kev. (10%), 630.8 kev. (0.024%), and 768.2 kev. (0.024%). These values are in good agreement with those quoted in the literature, except for the intensities of the last two radiations.

Investigations on the decay scheme of I131 in the low energy region of gamma-rays

1961 ◽  
Vol 24 (2) ◽  
pp. 318-321 ◽  
Author(s):  
Gy. Máthé ◽  
T. Scharbert ◽  
D. Berényi
Keyword(s):  
Gamma Rays ◽  
Energy Region ◽  
Decay Scheme ◽  
Low Energy

Level structure of 88Rb

1970 ◽  
Vol 48 (6) ◽  
pp. 753-758 ◽  
Author(s):  
H. Lycklama ◽  
T. J. Kennett
Keyword(s):  
High Resolution ◽  
Beta Decay ◽  
Gamma Rays ◽  
Decay Scheme ◽  
Level Structure ◽  
Good Efficiency

The beta decay of 2.8 h 88Kr has been investigated using a high-resolution and good efficiency 40 cm3 coaxial Ge(Li) counter. A total of 40 gamma rays were detected and determined to belong to the beta decay of 88Kr. All but one of these were placed in a consistent decay scheme. As a result it was possible to give a plausible interpretation to the level structure of 88Rb.

Levels of 186W from the Decay of 186Ta

1973 ◽  
Vol 51 (3) ◽  
pp. 241-256 ◽  
Author(s):  
S. C. Gujrathi ◽  
S. K. Mark
Keyword(s):  
Experimental Data ◽  
High Resolution ◽  
Excited States ◽  
Gamma Rays ◽  
Decay Scheme ◽  
Transition Probabilities ◽  
Recent Experimental Data ◽  
Particle State ◽  
Quasi Particle ◽  
Coincidence Data

Gamma rays from the decay of 10.5 min 186Ta have been studied using high resolution Ge(Li) detectors. More than 90 gamma rays have been observed. Several photo-peaks previously reported as single lines were found to be close doublets. The results of this study have been correlated with the published γ–γ coincidence data and the recent (d,d′) reaction work and a decay scheme for 186Ta has been constructed. The scheme incorporates more than 85 transitions among 23 excited states in 186W. The level at 1661 keV has been discussed in terms of a two-proton quasi-particle state arising from the Nilsson orbitals Ωπ[NnzΛ] = 7/2+[404] and 1/2+[411]. Several transition probabilities have been extracted and compared with other recent experimental data and with the calculations of Kumar and Baranger as well as with the predictions of various phenomenological models.

Gamma rays produced in the 209Bi(n, n′γ) reaction

1984 ◽  
Vol 62 (10) ◽  
pp. 948-962 ◽  
Author(s):  
W. V. Prestwich ◽  
T. J. Kennett ◽  
J. S. Tsai
Keyword(s):  
High Resolution ◽  
Gamma Rays ◽  
Energy Region ◽  
Weak Coupling ◽  
Decay Scheme ◽  
High Energy ◽  
High Energy Region ◽  
Γ Rays ◽  
Γ Ray ◽  
Resolution Study

A high-resolution study of the γ-ray spectrum induced by the inelastic scattering of reactor produced neutrons has been conducted. The γ rays observed have been assigned in a decay scheme involving 134 levels extending in excitation energy to 6 MeV. The results are discussed within the context of previously identified weak coupling configurations, and possible discrepancies are indicated. Levels in the high-energy region are also compared with recently reported photoexcitation studies.

Low Energy Gamma Transitions in 171Tm

1970 ◽  
Vol 25 (7) ◽  
pp. 1043-1045 ◽  
Author(s):  
M. S. El-Nesr
Keyword(s):  
High Resolution ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Low Energy ◽  
Conversion Coefficients ◽  
Energy Gamma ◽  
Gamma Transitions ◽  
Double Focusing

The low energy gamma-ray spectrum of 171Er has been studied with the use of both Ge (Li) gamma-ray and a high resolution iron free double focusing beta-ray spectrometer. The data provide K-conversion coefficients and multipolarities of eight gamma-rays. Spin and parity assignments 7/2+, 3/2+, 5/2+ and 5/2+ are given to the 636, 676, 738 and 913 keV levels respectively

Performance Evaluation of a Novel Type of Low-Energy Electron Microscope

1990 ◽  
Vol 48 (1) ◽  
pp. 354-355
Author(s):  
Bertholdand Senftinger ◽  
Helmut Liebl
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Field Strength ◽  
Numerical Aperture ◽  
Low Energy ◽  
Energy Electron ◽  
High Resolution Imaging ◽  
Lens System ◽  
Resolution Imaging ◽  
Low Energy Electron

During the last few years the investigation of clean and adsorbate-covered solid surfaces as well as thin-film growth and molecular dynamics have given rise to a constant demand for high-resolution imaging microscopy with reflected and diffracted low energy electrons as well as photo-electrons. A recent successful implementation of a UHV low-energy electron microscope by Bauer and Telieps encouraged us to construct such a low energy electron microscope (LEEM) for high-resolution imaging incorporating several novel design features, which is described more detailed elsewhere.The constraint of high field strength at the surface required to keep the aberrations caused by the accelerating field small and high UV photon intensity to get an improved signal-to-noise ratio for photoemission led to the design of a tetrode emission lens system capable of also focusing the UV light at the surface through an integrated Schwarzschild-type objective. Fig. 1 shows an axial section of the emission lens in the LEEM with sample (28) and part of the sample holder (29). The integrated mirror objective (50a, 50b) is used for visual in situ microscopic observation of the sample as well as for UV illumination. The electron optical components and the sample with accelerating field followed by an einzel lens form a tetrode system. In order to keep the field strength high, the sample is separated from the first element of the einzel lens by only 1.6 mm. With a numerical aperture of 0.5 for the Schwarzschild objective the orifice in the first element of the einzel lens has to be about 3.0 mm in diameter. Considering the much smaller distance to the sample one can expect intense distortions of the accelerating field in front of the sample. Because the achievable lateral resolution depends mainly on the quality of the first imaging step, careful investigation of the aberrations caused by the emission lens system had to be done in order to avoid sacrificing high lateral resolution for larger numerical aperture.

INNER SHELL STUDIES USING INELASTIC COINCIDENCE SPECTROSCOPY OF LOW ENERGY GAMMA RAYS

1987 ◽  
Vol 48 (C9) ◽  
pp. C9-823-C9-826
Author(s):  
S. MANNINEN ◽  
K. HÄMÄLÄINEN ◽  
T. PAAKKARI ◽  
P. SUORTTI
Keyword(s):  
Gamma Rays ◽  
Low Energy ◽  
Energy Gamma ◽  
Coincidence Spectroscopy

Evaluation of the uncertainty associated with sample holders in NAA measurements in LAN/IPEN

2019 ◽  
Vol 7 (2A) ◽  
Author(s):  
Guilherme Soares Zahn ◽  
Regina Beck Ticianelli ◽  
Mitiko Saiki ◽  
Frederico Antonio Genezini
Keyword(s):  
Stainless Steel ◽  
Neutron Activation Analysis ◽  
Neutron Activation ◽  
Gamma Rays ◽  
Experimental Error ◽  
Steel Sample ◽  
Low Energy ◽  
Stainless Steel Sample ◽  
Gamma Emission ◽  
Energy Gamma

In IPEN’s Neutron Activation Laboratory (LAN/IPEN), thin stainless steel sample holders are used for gamma spectrometry in NAA measurements. This material is very practical, but its chemical composition may be troublesome, as it presents large amounts of elements with intermediate atomic number, with attenuation factors for low-energy gamma-rays that must not be neglected. In this study, count rates obtained using different sample holders were compared. To accomplish that, an Am-241 source, with 59-keV gamma emission, was used so that low-energy gamma attenuation differences can be determined. Moreover, in order to study the energy dependence of these differences, a Ho-166m source was also used. From these results, it was possible to analyze the experimental error associated to the variations between sample holders, with the aim of introducing an addictive term to the uncertainty analysis of comparative Neutron Activation Analysis results.

Computational Study on the Kinetics and Mechanisms of Unimolecular Reactions of (Z)-(Z)-N-(λ5-phosphanylidene) Formohydrazonic Formic Anhydride: Intramolecular aza-Wittig Reaction in Competition with Mumm Rearrangement

2020 ◽  
Vol 17 (11) ◽  
pp. 884-889
Author(s):  
Somayeh Mirdoraghi ◽  
Hamed Douroudgari ◽  
Farideh Piri ◽  
Morteza Vahedpour
Keyword(s):  
Rate Constants ◽  
Density Functional ◽  
Wittig Reaction ◽  
Computational Study ◽  
Single Step ◽  
Low Energy ◽  
Coupled Cluster ◽  
Unimolecular Reaction ◽  
Single Step Reaction ◽  
Good Agreement

For (Z)-(Z)-N-(λ5-phosphanylidene) formohydrazonic formic anhydride, Aza-Wittig reaction and Mumm rearrangement are studied using both density functional and coupled cluster theories. For this purpose, two different products starting from one substrate are considered that are competing with each other. The obtained products, P1 and P2, are thermodynamically favorable. The product of the aza-Wittig reaction, P1, is more stable than the product of Mumm rearrangement (P2). For the mentioned products, just one reliable pathway is separately proposed based on unimolecular reaction. Therefore, the rate constants based on RRKM theory in 300-600 K temperature range are calculated. Results show that the P1 generation pathway is a suitable path due to low energy barriers than the path P2. The first path has three steps with three transition states, TS1, TS2, and TS3. The P2 production path is a single-step reaction. In CCSD level, the computed barrier energies are 14.55, 2.196, and 10.67 kcal/mol for Aza-Wittig reaction and 42.41 kcal/mol for Mumm rearrangement in comparison with the corresponding complexes or reactants. For final products, the results of the computational study are in a good agreement with experimental predictions.

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