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.

Proton?Capture Gamma Rays from Nitrogen?13

1962 ◽  
Vol 15 (3) ◽  
pp. 443 ◽  
Author(s):  
AW Parker ◽  
GG Shute
Keyword(s):  
Angular Distribution ◽  
Excited State ◽  
Elastic Scattering ◽  
Gamma Rays ◽  
Ground State ◽  
Recent Experiment ◽  
Gamma Ray ◽  
Angular Distributions ◽  
Proton Capture ◽  
Yield Curves

From a recent experiment in this laboratory (Shute et al. 1962) on the elastic scattering of protons from 12C, resonance levels (E13N, J1t) of 13N were obtained at the laboratory bombarding energies (Ep) shown in Table 1. To confirm these results, an investigation of the yield and angular distribution of gamma rays from the reaction 12C(p'YO)13N and 12C(p'Yl)13N was undertaken. Accordingly, the theoretical angular distributions, W(8), for the gamma ray (Yo) to the ground state of 13Na-) and also for the gamma ray (Yl) to the 1st excited state of 13Na+) were evaluated on the assumptions that overlap of levels in 13N is small and lowest order multipoles are involved. As angular distributions are parity insensitive, these were found to be identical for the two gamma rays expected. The simpler of these angular distributions are also shown on the table. The expected angular distributions indicate that 90� is a suitable angle for yield curves.

High-Purity Germanium Technology for Gamma-Ray and X-Ray Spectroscopy

1993 ◽  
Vol 302 ◽  
Author(s):  
L.S. Darken ◽  
C. E. Cox
Keyword(s):  
Cross Section ◽  
Gamma Rays ◽  
Ground State ◽  
High Purity ◽  
Gamma Ray ◽  
Capture Rate ◽  
X Rays ◽  
Hole Capture ◽  
High Purity Germanium ◽  
Energy Gamma

ABSTRACTHigh-purity germanium (HPGe) for gamma-ray spectroscopy is a mature technology that continues to evolve. Detector size is continually increasing, allowing efficient detection of higher energy gamma rays and improving the count rate and minimum detectable activity for lower energy gamma rays. For low-energy X rays, entrance window thicknesses have been reduced to where they are comparable to those in Si(Li) detectors. While some limits to HPGe technology are set by intrinsic properties, the frontiers have historically been determined by the level of control over extrinsic properties. The point defects responsible for hole trapping are considered in terms of the “standard level” model for hole capture. This model originates in the observation that the magnitude and temperature dependence of the cross section for hole capture at many acceptors in germanium is exactly that obtained if all incident s-wave holes were captured. That is, the capture rate is apparently limited by the arrival rate of holes that can make an angular-momentum-conserving transition to a s ground state. This model can also be generalized to other materials, where it may serve as an upper limit for direct capture into the ground state for either electrons or holes. The capture cross section for standard levels σS.L. is given bywhere g is the degeneracy of the ground state of the center after capture, divided by the degeneracy before capture. Mc is the number of equivalent extrema in the band structure for the carrier being captured, mo is the electronic mass, m* is the effective mass, and T is the temperature in degrees Kelvin.

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.

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.

Properties of low-lying states in 43Sc

1970 ◽  
Vol 48 (22) ◽  
pp. 2735-2750 ◽  
Author(s):  
G. C. Ball ◽  
J. S. Forster ◽  
F. Ingebretsen ◽  
C. F. Monahan
Keyword(s):  
Excited States ◽  
Gamma Ray ◽  
Level Structure ◽  
Surface Barrier ◽  
Angular Correlations ◽  
Mixing Ratios ◽  
Gamma Coincidence ◽  
Theoretical Predictions ◽  
Barrier Detector ◽  
Coincidence Spectra

The 40Ca(α, pγ)43Sc reaction at Eα = 11.8 to 15.5 MeV has been used to investigate the level structure of 43Sc below 4.2 MeV excitation. Level energies and decay schemes were determined from proton–gamma coincidence spectra obtained using an annular surface barrier detector positioned near 180° and two 40 cm3 Ge(Li) detectors. Angular correlations were measured in the same configuration using an array of six 12.7 × 15.2 cm NaI(Tl) detectors mounted on the Chalk River LOTUS goniometer. Twelve new levels were observed in 43Sc and information on the spins, branching ratios, and gamma-ray multipole mixing ratios of these and several other excited states has been obtained. The results are compared with recent theoretical predictions of Johnstone. In particular, levels at 1931 and 2552 keV, 1830 keV and 1883 keV have been tentatively assigned as the 9/2+ and probable 11/2+ members of the kπ = 3/2+ band, the (fp)3, Jπ = 11/2− state, and the 9/2− member of the kπ = 3/2− band, respectively.

ERRATA: THE VMI-MODEL REVISITED IN THE ODD-ODD RARE-EARTH NUCLEI

1993 ◽  
Vol 02 (04) ◽  
pp. 923-941
Author(s):  
A. K. JAIN ◽  
ALPANA GOEL
Keyword(s):  
Rare Earth ◽  
Moment Of Inertia ◽  
Rotational Bands ◽  
Complete Formulation ◽  
Rare Earth Nuclei ◽  
Energy Ratios ◽  
Interesting Correlation ◽  
Inertia Model ◽  
The Moment ◽  
Variable Moment

A rather complete formulation of the variable moment of inertia model is presented for odd-odd nuclei and relationship obtained between the energy ratios and the parameters of the model. Range of validity of the model is defined and Mallmann-like curves are obtained for the odd-odd nuclei. An application is made to the rare-earth region and results are presented for the K+=(Ωp+Ωn) bands and those K−=|Ωp−Ωn| bands which remain reasonably free from Coriolis mixing. The parameters obtained from the fitting show excellent agreement with the predictions of the model. An interesting correlation between the variation of the moment of inertia of the odd-odd rotational bands with those of the neighboring odd-A nuclei involving either the same neutron or same proton configuration is also presented.

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.

APPLICATION OF THE VARIABLE MOMENT OF INERTIA MODEL TO BANDS IN ODD-ODD NUCLEI

1990 ◽  
Vol 05 (29) ◽  
pp. 2403-2406 ◽  
Author(s):  
ALPANA GOEL ◽  
A. K. JAIN
Keyword(s):  
Angular Momentum ◽  
Significant Variation ◽  
Moment Of Inertia ◽  
Rotational Bands ◽  
Mixing Effects ◽  
Inertia Parameter ◽  
Rare Earth Nuclei ◽  
Inertia Model ◽  
The Moment ◽  
Variable Moment

The variable moment of inertia model is extended to rotational bands in odd-odd rare-earth nuclei. Results are presented for the K> = (Ωp + Ωn) bands which remain reasonably free from Coriolis mixing effects. The moment of inertia parameter exhibits significant variation with angular momentum which is strikingly similar to one of the odd-A rotational bands based on either the neutron or the proton configuration also involved in the odd-odd rotational band.

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.

A Kπ = 0− Octupole Band in 150Sm

1975 ◽  
Vol 53 (13) ◽  
pp. 1229-1235 ◽  
Author(s):  
J. V. Thompson ◽  
M. W. Johns ◽  
J. C. Waddington
Keyword(s):  
High Spin ◽  
Conversion Electron ◽  
Gamma Ray ◽  
Angular Distributions ◽  
Spin States ◽  
High Spin States ◽  
Gamma Coincidence

A study of the 148Nd(α, 2n)150Sm reaction has revealed the high spin states of a Kπ = 0− octupole band, the members of which become the yrast levels above spin 12. Gamma ray angular distributions, gamma–gamma coincidence, and conversion electron studies have established the levels of the octupole band at 1764.6(7−), 2232.1(9−), 2744.0(11−), and tentatively at 3293.0(13−) keV.

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