SPINS OF EXCITED STATES OF Os188

1959 ◽  
Vol 37 (6) ◽  
pp. 755-774 ◽  
Author(s):  
W. J. King ◽  
M. W. Johns
Keyword(s):  
Angular Correlation ◽  
Excited States ◽  
Beta Decay ◽  
Decay Scheme ◽  
Gamma Ray ◽  
Correlation Data ◽  
Conversion Coefficients

Seven excited states of Os188 populated through the beta decay of Re188 have been studied by gamma–gamma angular correlation experiments. The data for the various cascades fit the following theoretical functions: (all gamma-ray energies are in kev and the description following each cascade refers to the first transition) 478–155 (2–2–0, 99.7% E2, δ +ve), 931–155 (0–2–0), 672–633 (2–2–0), 97% M1, δ −ve or 3–2–0, 94% M1, δ −ve or conceivably 4–2–0), 828–633 (2–2–0, 98% M1, δ −ve or conceivably 3–2–0, 80% M1, δ −ve), 1132–633 (0–2–0), and 1308–633 (2–2–0, 98% M1, δ −ve). Some attenuation occurred in the correlations involving the 155-kev gamma ray. The K-conversion coefficients for the 478- and 633-kev transitions have been measured as 0.023 ± 0.003 and 0.010 ± 0.002 respectively, confirming the E2 character for these transitions obtained by angular correlation. These results, coupled with data concerning log ft values and gamma-ray intensities, lead to the following spin and parity assignments for levels in Os188: 155 (2+), 633 (2+), 1086 (0+), 1306 (2+ or 3+), 1461 (2+), 1765 (0+), 1941 (2+), and 1958 (1+ or 2+).The 631–137 correlation data in Os186 was found to fit an attenuated 2–2–0 function with the first transition 99% E2 and δ −ve. This result supports the established decay scheme for this nucleus.

THE DECAY OF Os191 AND Os193

1958 ◽  
Vol 36 (10) ◽  
pp. 1409-1429 ◽  
Author(s):  
S. V. Nablo ◽  
M. W. Johns ◽  
R. H. Goodman ◽  
A. Artna
Keyword(s):  
Excited States ◽  
Gamma Rays ◽  
Cross Sections ◽  
Decay Scheme ◽  
Internal Conversion ◽  
Gamma Ray ◽  
Internal Conversion Coefficients ◽  
Gamma Coincidence ◽  
Conversion Coefficients ◽  
Activation Cross Sections

The beta- and gamma-ray spectra of Os191 and Os193 have been studied with a magnetic beta-ray spectrometer, scintillation spectrometers, and coincidence circuits. The 14-hour isomer of Os191 decays via a 0.0742-Mev (M3) transition. Gamma rays of energy 0.0418 (100%, E3), 0.0809 (1%, M1 + E2), 0.1287 (100%, M1 + E2), and 0.1858 (0.1%) Mev have been found to be associated with the 14.6 ± 0.3 day decay of Os191 and an extension of the accepted decay scheme proposed. The following 19 transitions have been associated with the 31.5 ± 0.5 hour decay of Os193: 0.0730 (14%), 0.1068 (~1%), 0.1393 (10%), 0.180 (0.3%), 0.196 (0.1%), 0.243 (~0.2%), 0.2485 (0.3%), 0.2514 (0.4%), 0.278 (0.6%), 0.2810 (1.6%), 0.2885 (0.3%), 0.2994 (0.4%), 0.314 (0.3%), 0.3218 (1.7%), 0.3620 (0.6%), 0.3878 (1.6%), 0.4604 (4.1%), 0.4857 (0.3%), and 0.5585 (2.2%). The internal conversion coefficients for all the stronger transitions suggest that they are M1 + E2 in character. The decay energy of Os193 is 1.132 ± 0.005 Mev. Fermi analyses and beta–gamma coincidence experiments have established excited states of Ir193 at 0.073, 0.139, 0.281, 0.362, 0.460, and 0.559 Mev above the ground state. Six otherwise unclassified weak gamma rays can be accommodated if levels at 0.247, 0.315, and 0.613 Mev are included in the decay scheme.The activation cross sections of Os184 and Os190 are (2.2 ± 0.5) × 103and 5.3 ± 2 barns respectively, relative to Seren's value of 1.6 ± 0.4 barns for Os192.

scholarly journals Nuclear Structure Investigations of some Medium-Weight Isotopes

2021 ◽  
Author(s):  
◽  
Gavin Wallace
Keyword(s):  
Nuclear Structure ◽  
Beta Decay ◽  
Cross Section ◽  
Gamma Rays ◽  
Half Life ◽  
Decay Scheme ◽  
Gamma Ray ◽  
Calculated Cross Section ◽  
Beta Spectrum ◽  
Gamma Ray Detectors

<p>This thesis describes the methods and results of investigations made to determine the decay schemes of three short-lived isotopes 112Ag, 114Ag and 116Ag. A total of 76 gamma-rays was observed with a Ge(Li) detector in the gamma-radiation which follows the Beta-decay of 112Ag to levels of 112Cd. gamma- gamma coincidence and angular correlation measurements were made with Ge(Li)-NaI(T1) and NaI(T1)-NaI(T1) systems. A decay scheme consistent with the present data is proposed. Cross sections for the reactions 112Cd(n,p)112Ag and 115In(n, alpha)112Ag were measured, and the half-life of the 112Ag decay was found to be 3.14 plus-minus 0.01 hr. The decay scheme of 114Ag was studied with Ge(Li) gamma-ray detectors and plastic Beta-ray detectors. 9 of the 11 gamma-rays observed in the decay were incorporated into 114Cd level structure previously determined by conversion electron measurements on the 113Cd(n,gamma)114Cd reaction. The endpoint energy of the Beta-decay was determined as 4.90 plus-minus 0.26 MeV; no branching was evident in the Beta-spectrum. A decay scheme is proposed for which the Beta-branching was deduced from the measured gamma-ray yield and a calculated cross section value for the 114Cd(n,p)114Ag reaction. The 114Ag half-life was determined as 4.52 plus-minus 0.03 sec; a search for a previously reported isomeric state of 114Ag was unsuccessful. Ge(Li) and NaI(T1) gamma-ray detectors were used to study the direct and coincidence spectra that result from the decay of 116Ag, the half-life of which was found to be 2.50 plus-minus 0.02 min. 53 gamma-rays were observed from this decay. The Beta-branching to the 17 excited states of 116Cd in the proposed decay scheme was derived from the measured gamma-ray yield and a calculated cross section value for the 116Cd(n,p)Ag reaction. Spin and parity assignments for ihe energy levels of 116Cd are made. An investigation of the applicability of two collective models to nuclear structure typical of the Cd nuclei studied demonstrated that one of the models was misleading when applied to vibrational nuclei. A potential function was developed in the other model to extend the investigation to include a study of the transition between extremes of collective motion. This was used to examine the correspondence between nuclear level schemes representative of rotational and vibrational excitations.</p>

Study of thermal neutron capture in potassium

1970 ◽  
Vol 48 (10) ◽  
pp. 1109-1129 ◽  
Author(s):  
L. V. Johnson ◽  
T. J. Kennett
Keyword(s):  
Thermal Neutron ◽  
Excited States ◽  
Neutron Capture ◽  
Decay Scheme ◽  
Gamma Ray ◽  
Branching Ratios ◽  
Experimental Results ◽  
Thermal Neutron Capture ◽  
Gamma Coincidence

The 39K(n,γ)40K reaction has been studied using a Ge(Li) and a Ge(Li)–Ge(Li) spectrometer. A total of 252 gamma-ray transitions has been observed and a gamma–gamma coincidence matrix involving 62 transitions has been established. A decay scheme based on the experimental results is deduced for 202 of the observed gamma-ray transitions. Spins and parities of some excited states have been estimated from the deduced branching ratios. The neutron separation energies of the 40K and 42K nuclei have been determined as 7800.5 ± 0.2 and 7535.2 ± 1.5 keV respectively.

Study of levels in 24Mg

1968 ◽  
Vol 46 (12) ◽  
pp. 1381-1401 ◽  
Author(s):  
R. W. Ollerhead ◽  
J. A. Kuehner ◽  
R. J. A. Levesque ◽  
E. W. Blackmore
Keyword(s):  
Angular Correlation ◽  
Beta Decay ◽  
Rotational Band ◽  
Ground State ◽  
Present Experiment ◽  
Gamma Ray ◽  
Axially Symmetric ◽  
Excitation Energies ◽  
Rotational Model ◽  
Rotational Bands

Nineteen levels in 24Mg have been studied utilizing the reaction 12C(16O, αγ)24Mg. Angular correlation measurements have established the spins and parities of levels at excitation energies of 7.35, 7.56, 7.62, 8.44, 8.65, 9.00, 9.15, and 10.1 MeV as 2+, 1−, 3−, 1−, 2+, 2+, 1−, and 0+ respectively. Levels at 8.12 and 13.18 MeV have been identified as the 6+ and 8+ members of the K = 0 ground-state rotational band; levels at 7.81 and 9.52 MeV have been identified as the 5+ and 6+ members of the K = 2 rotational band based on the 2+ level at 4.23 MeV. The existence of doublets has been established at excitation energies of 8.44 and 9.52 MeV; in each case, one member of the doublet is populated in the beta decay of 24Al, and the present experiment indicates that these two levels have spin and parity 4+. Assignments are also suggested for levels at 7.75 MeV (1+) and 8.36 MeV (2+). Gamma-ray spectra have been obtained for levels at 8.86, 9.28, and 9.46 MeV. The properties of levels assigned to rotational bands are compared to the predictions of the rotational model for an axially symmetric nucleus.

Level Structure of 171Tm

1972 ◽  
Vol 50 (6) ◽  
pp. 513-528 ◽  
Author(s):  
R. L. Graham ◽  
J. S. Geiger ◽  
M. W. Johns
Keyword(s):  
Excited States ◽  
Internal Conversion ◽  
Gamma Ray ◽  
Level Structure ◽  
Line Intensities ◽  
Gamma Coincidence ◽  
Coincidence Data ◽  
Conversion Coefficients ◽  
Beta Spectrometer

The properties of the γ-ray transitions in 171Tm, following beta decay of 7.5 h 171Er, have been studied using an iron-free π√2 beta spectrometer and Ge(Li) detectors, singly and in coincidence. The multipolarities of 8 lower-energy γ transitions have been established from a study of L- or M-subshell-internal-conversion lines. The measured K-line intensities of 20 higher-energy transitions yield K conversion coefficients and hence additional multipolarity assignments. Gamma-ray energy measurements, together with an extensive series of gamma–gamma coincidence experiments, have been used to establish the role of 59 (out of 65) γ transitions in the 171Tm level scheme. Sixteen excited states are identified at energies of 5.025 (3/2+), 116.6 (5/2+), 129.0 (7/2+), 326.7* (9/2+), 424.8 (7/2−), 635.4 (7/2+), 675.7 (3/2+), 737.2 (5/2+), 822.3* (7/2+), 912.8 (5/2+), 998.6 (7/2+), 1225.5* (3/2, 5/2, or 7/2+), 1284.7* (5/2+), 1296.3*, 1391.2*, and 1400.5* (5/2+) keV. The asterisks indicate levels which are new or at variance with those proposed by some other workers. The coincidence data does not support a level at 861 keV proposed by two other groups of workers on the basis of energy sums. Nilsson orbital assignments are proposed and discussed for 12 levels.

A study of the levels in 19 F following the -decay of 19 O

1959 ◽  
Vol 252 (1268) ◽  
pp. 1-15 ◽  
Keyword(s):  
Angular Correlation ◽  
Excited States ◽  
Decay Scheme ◽  
Transition Probabilities ◽  
Theoretical Calculations ◽  
Collective Model ◽  
Particle Model ◽  
Β Decay ◽  
Intermediate Coupling ◽  
The Individual

The β-decay scheme of 19 O to states of 19 F has been determined, and log ft values assigned to the individual transitions, by studying the y-rays following β-decay. The decay schemes of the levels in 19 F have been elucidated by coincidence and angular correlation measurements. These measurements have enabled characteristics to be assigned to the excited states of 19 F, and relative y-transition probabilities have been determined. The results are compared with theoretical calculations on the individual-particle model in intermediate coupling and on the collective model.

Decay of 142La

1971 ◽  
Vol 49 (9) ◽  
pp. 1179-1185 ◽  
Author(s):  
S. L. Tong ◽  
W. V. Prestwich ◽  
K. Fritze
Keyword(s):  
Excited States ◽  
Beta Decay ◽  
Gamma Rays ◽  
Proportional Counter ◽  
Decay Scheme ◽  
Branching Ratios ◽  
Coincidence Measurement

The energies of the gamma rays following the beta decay of 92.5 min 142La have been precisely measured, and a coincidence measurement with a NaI(Tl) and Ge(Li) system was made by gating the NaI(Tl) at 641 keV. With these results, the decay scheme of 142Ce derived by Prestwich and Kennett was modified. The beta branching ratios of the decay of 142La to the ground and excited states of 142Ce have also been obtained by simultaneous gamma and 4π beta countings with a 3 in. × 3 in. NaI(Tl) detector and a 4π-proportional counter.

K X-Ray and Gamma-Ray Angular Correlations in the Decay of 113Sn and 133Ba, using a High Efficiency Sum-Peak Coincidence Scintillation Spectrometer

1971 ◽  
Vol 49 (13) ◽  
pp. 1769-1772 ◽  
Author(s):  
K. Venkata Ramana Rao ◽  
V. Lakshminarayana
Keyword(s):  
Angular Correlation ◽  
Beta Decay ◽  
High Efficiency ◽  
Gamma Ray ◽  
X Ray ◽  
Angular Correlations ◽  
Nuclear Environment

K-capture isotopes 113Sn and 133Ba are used with a sum-peak coincidence scintillation spectrometer arrangement to study the K X-ray – gamma-ray angular correlation. The effects of the type of beta decay, the nuclear environment, and three-gamma cascades with intermediate gamma ray unobserved are investigated. No anisotropy could be detected, supporting the theory of Dolginov.

Excited states in 75As

1970 ◽  
Vol 48 (19) ◽  
pp. 2254-2264 ◽  
Author(s):  
Th. Paradellis ◽  
S. Hontzeas
Keyword(s):  
Excited States ◽  
Half Life ◽  
Gamma Ray ◽  
Collective Effects ◽  
Transition Rates ◽  
Electron Conversion ◽  
Conversion Coefficients ◽  
First Time ◽  
Coincidence Measurements

The gamma-ray spectrum of 75Se has been studied with a variety of Ge(Li) detectors. The energies and intensities of 15 lines have been accurately measured. Of these a 24.4 and 468.6 keV transition were substantiated for the first time in the gamma-ray spectrum. Ge(Li)–Ge(Li) coincidence measurements established the newly observed 24.4 keV transition. These experiments also substantiated the 80.8 keV transition (observed for the first time) deduced from electron conversion spectra. The accurate intensity values obtained in this work have been combined with proper literature data and conversion coefficients for various transitions have been determined. These data and recent half-life measurements of some excited states by other workers permitted us to calculate the transition rates in 75As. The data obtained indicate that the 198.6, 279.5, and 400.5 keV levels in 75As exhibit strong collective character, in contrast to the 264.6 keV level, which shows little influence of collective effects.

Levels populated in 193Ir from the beta decay of 193Os

1969 ◽  
Vol 47 (7) ◽  
pp. 727-746 ◽  
Author(s):  
R. H. Price ◽  
M. W. Johns ◽  
N. M. Ahmed ◽  
E. E. Habib
Keyword(s):  
Beta Decay ◽  
Internal Conversion ◽  
Gamma Ray ◽  
Magnetic Spectrometer ◽  
Mixing Ratios ◽  
Internal Conversion Coefficients ◽  
Conversion Coefficients ◽  
Coincidence Measurements

The beta and gamma ray transitions involved in the decay of 193Os have been studied using Ge(Li) and Nal(Tl) detectors and magnetic spectrometers, singly and in coincidence. Fifty-four gamma ray transitions have been observed and all but one classified on the basis of energy fit and β−γ and γ−γ coincidence measurements. The internal conversion coefficients of 25 of the stronger transitions were determined with a magnetic spectrometer operating at a resolution of ~0.1% in momentum, and multipole mixing ratios determined. The energies and spins of levels in 193Ir have been determined as follows: 0 (3/2+), 73.006 (1/2+), 138.887 (5/2+), 142.125 (+), 180.00(3/2+), 357.7 (7/2+), 361.79 (5/2+), 440.95 (+), 460.46 (3/2+), 557.29 (1/2+), 559.22 (5/2+), 660.09 (+), 667.13, 695.06 (3/2+), 712.08 (3/2+), 778.50,784.13, 848.94, 874.45, 891.57.

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