STUDIES IN THE ACTIVE DEPOSIT OF ACTINIUM: PART II: THE DECAY OF 211Pb (AcB)

1965 ◽  
Vol 43 (3) ◽  
pp. 383-403 ◽  
Author(s):  
C. R. Cothern ◽  
R. D. Connor
Keyword(s):  
Gamma Rays ◽  
Level Scheme ◽  
Gamma Ray ◽  
Ground Level ◽  
Conversion Line ◽  
Point Energy ◽  
Correlation Studies ◽  
Absolute Intensities ◽  
Gamma Coincidence ◽  
Conversion Coefficients

Studies of the active deposit of actinium using a Siegbahn–Slatis beta-ray spectrometer and scintillation counters together with gamma–gamma coincidence work and gamma–gamma angular correlation measurements have led to the establishment of a new decay scheme for 211Pb and a level scheme for 211Bi involving five excited states.The gamma rays have the following energies and absolute intensities:[Formula: see text]Conversion-line studies yielded energy values for the transitions marked with an asterisk as 403.3 ± 0.5 and 426.5 ± 0.5 keV respectively. The K conversion coefficients of the 400- and 430-keV transitions have been determined as 0.091 ± 0.018 and 0.117 ± 0.024 respectively.Fermi analysis yields 1.378 MeV as the highest end-point energy of the beta partial spectra. The remaining end points and the component intensities as deduced from the level scheme are as follows:[Formula: see text]The much less accurate results from Fermi analysis of the complete active deposit are in reasonable agreement with these data.Angular correlation studies of the 430–400- and 706–400-keV gamma-ray cascades have yielded spins for the levels concerned: ground level (9/2), 400-keV level (7/2), 830-keV level (9/2), and 1 100-keV level (7/2). These spins are the only ones consistent with the experimental evidence and the theoretical arguments presented.

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.

High spin states in 96Tc populated through the (α,n) reaction

1980 ◽  
Vol 58 (2) ◽  
pp. 174-190 ◽  
Author(s):  
H. A. Mach ◽  
M. W. Johns ◽  
J. V. Thompson
Keyword(s):  
Theoretical Model ◽  
High Spin ◽  
Spin Structure ◽  
Gamma Ray ◽  
Angular Distributions ◽  
Spin States ◽  
High Spin States ◽  
Gamma Coincidence ◽  
Electron Conversion ◽  
Conversion Coefficients

High spin states of 96Tc populated by the (α,n) reaction using alpha beams from 13 to 27 MeV have been studied. Gamma-ray energies and intensities, gamma–gamma coincidence probabilities, gamma-ray angular distributions, and electron conversion coefficients were determined at 18 MeV. In addition, some results taken at 14 MeV are reported.The high spin structure observed in this work includes the following levels: 49.3(6+), 318.8(6+), 574.7(7+), 926.9(9+), 946.5(8+), 1062.1(8+), 1138.8(8+), 1447.2(9+), 1702.8(10+), 1861.6(9+), 1922.3(11+), 2147.5(11+), 2213.5(10(+)), 2317.2(12+), 2396.8(11(+)), 2599.0((13)+), 2642.4((14)+), and 3020.1(12(+)).These experiments also clarify and extend the information obtained by previous workers. In particular, evidence is adduced for low-lying states at 0.0(7+), 34.3(4+), 45.3(5+), 120.3(3−), 177.0(5+), 226.2(2−), 227.0(4+), and 254.3(3+).The work identifies many other states of intermediate energy.Attenuation coefficients for states in 96Tc are calculated using a theoretical model.

Beta decay of 187W

1970 ◽  
Vol 48 (9) ◽  
pp. 1040-1054 ◽  
Author(s):  
A. W. Herman ◽  
E. A. Heighway ◽  
J. D. MacArthur
Keyword(s):  
Excited State ◽  
Beta Decay ◽  
Decay Scheme ◽  
Decay Energy ◽  
Beta Transition ◽  
Point Energy ◽  
Absolute Intensities ◽  
Gamma Coincidence ◽  
First Excited State ◽  
Coincidence Measurements

Coincidence studies have established in the decay scheme of,187W the existence of transitions of energy 7, 36, 77, 455, 589, and 639 keV with intensities of 3.0 ± 0.5%, 0.50 ± 0.06%, 0.31 ± 0.07%, 0.05 ± 0.02%, 0.14 ± 0.04%, and 0.05 ± 0.02% respectively as well as yielding the absolute intensities of the well-known transitions in 187Re. In addition the beta–gamma coincidence measurements have shown that (1) a first-forbidden unique transition feeds the first-excited state of 187Re, (2) there is at most a very weak beta transition to the level at 512 keV, (3) there is no inner beta group of about 300 keV end-point energy and intensity 8% as indicated by several earlier investigations, and (4) the decay energy of 187W to 187Re is 1311 ± 2 keV. The relevance of these observations to the structure of 187Re is discussed.

Levels in 89Rb Populated by the Beta Decay of 89Kr

1972 ◽  
Vol 50 (22) ◽  
pp. 2741-2752 ◽  
Author(s):  
W. F. S. Poehlman ◽  
B. Singh ◽  
M. W. Johns
Keyword(s):  
Excited States ◽  
Beta Decay ◽  
Gamma Rays ◽  
Large Volume ◽  
Ground State ◽  
Level Scheme ◽  
Gamma Coincidence ◽  
Coincidence Data ◽  
Coincidence Arrangement

The decay of 3.2 min 89Kr has been investigated with small and large volume Ge(Li) detectors used singly and in a dual parameter coincidence arrangement. A total of 162 gamma rays are identified with the decay of this isotope, 120 of which are placed in a level scheme on the basis of gamma–gamma coincidence evidence and the energy differences between established levels. Levels at 220.9, 497.7, 577.3, 586.1, 930.7, 931.5, 997.6, 1195.5, 1324.6, 1530.1, 1533.6, 1694.1, 1822.1, 1998.9, 2160.5, 2401.5, 2598.5, 2867.2, 3099.7, 3329.9, 3363.1, 3372.1, 3534.1, 3719.3, 4145.1, 4217.4, 4340.9, and 4487.5 keV are well established by coincidence data and many energy sums. The levels proposed at 2783.4, 3429.7, 3456.6, 3978.4, 4058.4, and 4406.5 keV are less securely established. The most probable spins of the ground state and the first two excited states arc 3/2−. 5/2− and 1/2− respectively. Improved energies and intensities of the gamma rays from the decay of 15 min 89Rb have also been determined.

Lifetimes and branching ratios of energy levels of 28Si. I

1969 ◽  
Vol 47 (6) ◽  
pp. 639-649 ◽  
Author(s):  
A. E. Litherland ◽  
P. J. M. Smulders ◽  
T. K. Alexander
Keyword(s):  
Gamma Rays ◽  
Gamma Ray ◽  
Energy Levels ◽  
Ground Level ◽  
Particle Beam ◽  
High Energy ◽  
Branching Ratios ◽  
Alpha Particles ◽  
Doppler Shift Attenuation ◽  
Energy Gamma

The gamma rays from the 25Mg(α,nγ)28Si reaction have been studied using alpha particles with energies ranging from 4.8 to 6.0 MeV. A 25 cm3 Ge(Li) gamma-ray counter was used to observe the complex high energy gamma-ray spectra at angles between 0° and 130° to the alpha-particle beam. Estimates of the nuclear lifetimes of the energy levels excited were obtained from Doppler shift attenuation measurements. The de-excitation branching ratios of the levels were also measured. The existence of a new level in 28Si at 6695 keV was confirmed. The recently reported 3− level at either 6880 keV or 6889 keV was observed and found to be the 6880-keV member of the doublet. The enhancement of the octupole transition to the ground level of 28Si was found to be 13 Weisskopf units.

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.

scholarly journals Ground-Based Observations of Terrestrial Gamma Ray Flashes Associated with Downward-Directed Lightning Leaders

2019 ◽  
Vol 197 ◽  
pp. 03002
Author(s):  
Rasha Abbasi ◽  
John Belz ◽  
Ryan Le Von ◽  
Dan Rodeheffer ◽  
Paul Krehbiel ◽  
...  
Keyword(s):  
Electric Field ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Three Dimensional ◽  
Temporal Distribution ◽  
Cosmic Ray ◽  
Ground Level ◽  
High Energy ◽  
Lightning Strikes ◽  
Lightning Discharges

Terrestrial gamma-ray flashes (TGFs) are bursts of gamma-rays initiated in the Earth’s atmosphere. TGFs were serendipitously first observed over twenty years ago by the BATSE gamma ray satellite experiment. Since then, several satellite experiments have shown that TGFs are produced in the upward negative breakdown stage at the start of intracloud lightning discharges. In this proceeding, we present ground-based observation of TGFs produced by downward negative breakdown occurring at the beginning of negative cloud-to-ground flashes. The Terrestrial gamma-ray flashes discussed in this work were detected between 2014-2017 at ground level by the Telescope Array surface detector (TASD) together with Lightning Mapping Array (LMA) and the slow electric field antenna (SA). The TASD detector is a 700 km2 ultra high energy cosmic ray detector in the southwestern desert of Utah. It is comprised of 507 (3 m2) plastic scintillator detectors on a 1.2 km square grid. The LMA detector, a three-dimensional total lightning location system, is comprised of nine stations located within and around the array. The slow electric field antenna records the electric field change in lightning discharges. The observed Gamma ray showers were detected in the first 1-2 ms of downward negative breakdown prior to cloud-to-ground lightning strikes. The shower sources were observed by the LMA detector at altitudes of a few kilometers above ground level. The detected energetic burst showers have a footprint on the ground typically ~ 3-5 km in diameter. The bursts comprise of several (2-5) individual pulses, each of which have a span of a few to tens of microseconds and an overall duration of several hundred microseconds. Using a forward-beamed cone of half-angle of 16 degrees, GEANT simulation studies indicate that the showers are consistent with gamma rays of 1012 - 1014 primary photons. We hypothesize that the observed terrestrial gamma-ray flashes are similar to those detected by satellites, but that the ground-based observations are closer to the source and therefore are able to observe weaker sources and report on the structure of the temporal distribution at the source. This result and future studies will enable us to better identify and constrain the mechanisms of downward TGF production.

High-resolution gamma-ray study of 185Wm

1970 ◽  
Vol 48 (5) ◽  
pp. 502-510 ◽  
Author(s):  
S. C. Gujrathi ◽  
J. M. D'auria
Keyword(s):  
High Resolution ◽  
Gamma Rays ◽  
Ground State ◽  
Internal Conversion ◽  
Gamma Ray ◽  
X Ray ◽  
Isomeric Level ◽  
Coincidence System ◽  
Internal Conversion Coefficients ◽  
Conversion Coefficients

The decay of 185Wm has been investigated using a high-resolution Ge(Li) X-ray spectrometer and a Ge(Li)–NaI(Tl) coincidence system. The energies and relative intensities (given in parentheses) of the observed gamma rays associated with the decay of the 185Wm (T1,2 = 1.68 min) are: 23.54 (3.3), 42.29 (1.1), 65.857 (100), 93.30 (0.5), 94.59 (2.2), 107.850 (6.8), 122.05 (1.5), 131.554 (84.0), 164.334 (11), 173.675(61.5),and 187.879(15.4) keV. The energy of the isomeric level has been deduced to be 197.41 keV and decays to the ground state through levels at 187.88, 173.68, 93.29, 65.86, and 23.54 keV. In addition, it was deduced experimentally from measured internal-conversion coefficients that the multipolarity of the 131.55 keV transition is E3 while the 65.86 keV transition is an M1 + E2 mixture with a 30 ± 7.5% M1 component.

scholarly journals Gamma-Ray Lines from Solar Flares

1975 ◽  
Vol 68 ◽  
pp. 363-383 ◽  
Author(s):  
R. Ramaty ◽  
R. E. Lingenfelter
Keyword(s):  
Gamma Rays ◽  
Solar Flares ◽  
Neutron Capture ◽  
Gamma Ray ◽  
Nuclear Reactions ◽  
The Other ◽  
Line Production ◽  
Absolute Intensities ◽  
Flare Region ◽  
Accelerated Particles

We have treated in detail the theory of gamma-ray line production in solar flares. The strongest line, both predicted theoretically and detected observationally at 2.2 MeV, is due to neutron capture by protons in the photosphere. The neutrons are produced in nuclear reactions of flare accelerated particles which also produce positrons and prompt nuclear gamma rays. From the comparison of the observed and calculated intensities of the lines at 4.4 or 6.1 MeV to that of the 2.2 MeV line it is possible to deduce the spectrum of accelerated nuclei in the flare region; and from the absolute intensities of these lines it is possible to obtain the total number of accelerated nuclei at the Sun. The study of the 2.2 MeV line also gives information on the amount of He3 in the photosphere. The study of the line at 0.51 MeV resulting from positron annihilation complements the data obtained from the other lines; in addition it gives information on the temperature and density in the annihilation region and on the anisotropy of the accelerated electron beam which produces continuum gamma rays at energies greater than about 1 MeV.

14.—Ground State Rotational Bands in 158Dy, 160Dy and 162Dy

1972 ◽  
Vol 70 ◽  
pp. 155-163 ◽  
Author(s):  
G. T. Ewan ◽  
G. I. Andersson
Keyword(s):  
Gamma Rays ◽  
Ground State ◽  
Gamma Ray ◽  
Angular Distributions ◽  
Rotational Bands ◽  
Weak Evidence ◽  
Gamma Coincidence ◽  
Inertia Model ◽  
Coincidence Spectra ◽  
Variable Moment

SynopsisLevels in the ground state bands of 158Dy, 160Dy and 162Dy have been populated by (α, 2n) reactions on metallic targets of separated 156Gd, 158Gd and 160Gd isotopes. Two Ge(Li) detectors were used to study singles gamma-ray spectra, gamma-ray angular distributions, gamma-gamma coincidence spectra and relative yields of gamma-rays for bombarding energies from 20 to 27 MeV. Transitions from all levels in the ground state bands up to the 12+ member were identified and the following level energies in keV established: 158Dy: 0 (0+), 99·0 (2+), 317·4 (4+), 637·9 (6+), 1044·1 (8+), 1520·1 (10+) and 2049·4 (12+); 160Dy: 0 (0+), 86·7 (2+), 283·7 (4+), 581·4 (6+), 967·4 (8+), 1429·0 (10+), 1951·7 (12+); 162Dy: 0 (0+), 80·7 (2+), 265·7 (4+), 548·5 (6+), 921·1 (8+), 1374·8 (10+) and 1901·0 (12+). There is weak evidence for the 14+ levels in 158Dy and 160Dy. The level energies are compared with calculated values using the variable moment of inertia model.

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