Nuclear alinement of manganese-56

1959 ◽  
Vol 250 (1263) ◽  
pp. 550-561 ◽  
Keyword(s):  
Angular Distribution ◽  
Excited State ◽  
Angular Correlation ◽  
Excited States ◽  
Daughter Nucleus ◽  
Γ Radiation ◽  
Mixing Ratios ◽  
First Excited State ◽  
Γ Rays ◽  
Coincidence Measurements

The present work demonstrates the feasibility of alining manganese-56 produced by neutron irradiation of a nickel fluosilicate crystal containing stable 55 Mn. Measurements were made of the angular distribution of the γ-radiation from the alined 56 Mn and also of the angular correlation of the γ-rays from this isotope. By combining the results it is possible to establish uniquely as 2 the spins of the states of the daughter nucleus of 56 Fe at 2.66 and 2.98 MeV. The mixing ratios δ ( E 2/ M 1) for the 1.81 and 2.13 MeV γ-rays to the first excited state are shown to be 0.19 ± 0.02 and — 0.28 ± 0.02. The spectrum of the γ-radiation was studied with a scintillation spectrometer and this leads to the following relative intensities; 0.845 MeV (100%), 1.81 MeV (27 ± 3%), 2.13 MeV (15 ± 3%), 2.55 MeV (1.2 ± 0.2%), 2.66 MeV (0.65 ± 0.1%), 2.98 MeV (0.35 ± 0.1%) and 3.4 MeV (0.22 ± 0.05%). Coincidence measurements suggest that the 2.55 and 3.4 MeV γ-rays are due to de-excitation of a level at about 3.4 MeV which decays both to the ground and first excited states. A spin of 2 for this state is proposed.

Positive-Parity Bands in 29Si

1971 ◽  
Vol 49 (10) ◽  
pp. 1263-1274 ◽  
Author(s):  
A. A. Pilt ◽  
R. H. Spear ◽  
R. V. Elliott ◽  
J. A. Kuehner
Keyword(s):  
Angular Distribution ◽  
Excited State ◽  
Linear Polarization ◽  
Ground State ◽  
Gamma Ray ◽  
Positive Parity ◽  
Rotational Bands ◽  
Mixing Ratios ◽  
First Excited State ◽  
Nilsson Model

A study has been made of several high spin members of the ground state (Kπ = 1/2+) and first-excited state (Kπ = 3/2+) rotational bands in the presumed oblate nucleus 29Si. Gamma-ray angular distribution and linear polarization measurements have confirmed the spin and parity of the 4081 keV level to be 7/2+, and levels at 4742 and 5283 keV have been shown to have Jπ = 9/2+ and (7/2+, 3/2+) respectively. Branching and mixing ratios for the transitions from these states have also been determined; in conjunction with previously measured lifetimes, transition strengths are calculated. The results are compared with the predictions of a Nilsson-model calculation including the effects of coriolis mixing of the low-lying positive parity bands.

THE EFFECT OF INTERACTIONS ON THE ANGULAR DISTRIBUTION OF γ-RAYS FROM AN ASSEMBLY OF ORIENTED NUCLEI

1957 ◽  
Vol 35 (9) ◽  
pp. 1133-1145 ◽  
Author(s):  
J. M. Daniels
Keyword(s):  
Angular Distribution ◽  
Energy State ◽  
Nuclear Orientation ◽  
Γ Radiation ◽  
Orientation Experiment ◽  
High Temperature Approximation ◽  
Γ Rays ◽  
Matrix Formula ◽  
Paramagnetic Ions ◽  
Radioactive Ions

The angular distribution of γ-radiation from an assembly of nuclei oriented by the magnetic h.f.s. method can be very much modified by interactions between the radioactive ions and other paramagnetic ions in the crystal. In order to calculate the effect of these interactions, an operator Γ is derived which represents the angular distribution of γ-rays from a radioactive nucleus. The angular distribution at any temperature is given by Spur(Γρ), where ρ is the statistical matrix [Formula: see text], [Formula: see text] being the Hamiltonian for the whole crystal. For a high temperature approximation, ρ is expanded in powers of 1/T. It is found that, for alignment by the magnetic h.f.s. method, the first term which contains interaction parameters is that in 1/T4, and an expression is given for the contribution of interactions to this term.At very low temperatures, perturbation theory is used to estimate the effect of interactions on the lowest nuclear energy state, and hence on the angular distribution of γ-rays. It is found that, if an external magnetic field is applied along a principal axis of the g-tensor of the radioactive ions, interactions have no influence on the angular distribution of γ-rays in the limit of large fields. It is also shown that Bleaney's restriction, that for a successful nuclear orientation experiment the broadening of the levels should be less than the hyperfine splitting, is not necessary in this case.

scholarly journals GDR Contribution to Coulomb Excitation. II. 17O

1982 ◽  
Vol 35 (3) ◽  
pp. 301 ◽  
Author(s):  
FC Barker
Keyword(s):  
Excited State ◽  
Shell Model ◽  
Excited States ◽  
Giant Dipole Resonance ◽  
Coulomb Excitation ◽  
Dipole Resonance ◽  
First Excited State ◽  
Virtual Excitation

The contribution to the Coulomb excitation of the first excited state of 170 due to virtual excitation of the giant dipole resonance (GDR) is calculated, using shell model wavefunctions for the ground and first excited states. A large value is obtained.

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.

scholarly journals Effect of Excited-state Decays on the Measured Angular Distribution of the 12C(g, p)11B Reaction

1974 ◽  
Vol 27 (3) ◽  
pp. 301 ◽  
Author(s):  
Judith M Dixon ◽  
MN Thompson
Keyword(s):  
Angular Distribution ◽  
Excited State ◽  
Excited States ◽  
Cross Section ◽  
Proton Decay ◽  
Small Cross Section

The angular distribution of photoprotons from i2e as measured directly and as deduced from the inverse reaction are compared. A discrepancy is revealed; it is resolved by proposing a small cross section for proton decay to excited states of 11 B. The size

Coincidence measurements of the first excited state of 73Ge

1970 ◽  
Vol 48 (8) ◽  
pp. 930-934 ◽  
Author(s):  
D. G. Douglas
Keyword(s):  
Excited State ◽  
Half Life ◽  
Conversion Coefficient ◽  
Coincidence Measurement ◽  
First Excited State ◽  
Coincidence Measurements

A coincidence measurement of the K conversion coefficient of the 13.26 keV transition from the first excited state of 73Ge yields a result closer to the E2 theoretical value than that of an earlier less-precise measurement.The half-life of the level is found to be 2.95 ± 0.05 s in agreement with one of two disagreeing previous values.

GAMMA-RAY ANGULAR CORRELATION MEASUREMENTS IN Ne22

1964 ◽  
Vol 42 (6) ◽  
pp. 1300-1310 ◽  
Author(s):  
C. Broude ◽  
M. A. Eswaran
Keyword(s):  
Excited State ◽  
Angular Correlation ◽  
Gamma Ray ◽  
Amplitude Ratio ◽  
Spin Assignment ◽  
Primary Radiation ◽  
Angular Correlations ◽  
First Excited State

Coincidence gamma-ray angular correlations of the cascade decays from the 3.34- and 4.47-Mev states in Ne22 through the first excited state have been measured. The levels were excited by the reaction F19 (α, p)Ne22. The correlations give an unambiguous spin assignment of 4 to the 3.34-Mev state; the analysis of the correlations from the 4.47-Mev state is not unique, allowing spin 2 or 3. The quadrupole-to-dipole amplitude ratio for the primary radiation is −0.11 ± 0.03 or −1.07 ± 0.10, respectively, for the spin-2 and spin-3 assignments.

THE SPIN OF THE 3.70-MEV LEVEL IN Al25

1963 ◽  
Vol 41 (6) ◽  
pp. 923-931 ◽  
Author(s):  
G. J. McCallum
Keyword(s):  
Angular Distribution ◽  
Excited State ◽  
Band Structure ◽  
Ground State ◽  
Transition Probability ◽  
Spin Assignment ◽  
Mixing Ratio ◽  
Excitation Radiation ◽  
Rotational Bands ◽  
First Excited State

The 3.70-Mev level in Al25 has been studied by means of the reaction Mg24(p, γ)Al25 at the 1.49-Mev resonance. Direct angular distribution measurements of the de-excitation gamma radiation support the spin assignment of 7/2− for this level. An E2/M1 amplitude mixing ratio of −0.55 ± 0.2 is found for the 1.79-Mev de-excitation radiation from the fourth excited state to the ground state of Al25. The ratio of the reduced transition probability of the E2 radiation from the 1.79-Mev level to the first excited state is shown to be ~30 times that to the ground state. This result provides further confirmation of rotational band structure in Al25 since the collective model predicts such an enhancement of E2 transitions between rotational bands whereas cross-band transitions are not expected to be enhanced.

THE ANGULAR DISTRIBUTION OF GAMMA RAYS IN THE C12(p,p′γ) REACTION

1953 ◽  
Vol 31 (2) ◽  
pp. 189-193 ◽  
Author(s):  
H. E. Gove ◽  
N. S. Wall
Keyword(s):  
Angular Momentum ◽  
Angular Distribution ◽  
Excited State ◽  
Proton Beam ◽  
Gamma Rays ◽  
Ground State ◽  
Expansion Formula ◽  
First Excited State ◽  
Incoming Proton

Protons of 7.1 Mev. energy from the MIT cyclotron have been used to investigate the angular distribution of gamma rays from the C12(p,p′γ) reaction with respect to the incoming proton beam. These gamma rays result from transitions between the first excited state of C12 at 4.45 Mev. and the ground state. The resulting distribution can be fitted by the expansion[Formula: see text]which is consistent with an assignment of two for the angular momentum of the first excited state of C12.

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