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.

PROPERTIES OF LEVELS AT 6.69 AND 6.88–6.89 MeV IN 28Si

1966 ◽  
Vol 44 (5) ◽  
pp. 1087-1097 ◽  
Author(s):  
R. J. A. Levesque ◽  
R. W. Ollerhead ◽  
E. W. Blackmore ◽  
J. A. Kuehner
Keyword(s):  
Excited State ◽  
Alpha Particle ◽  
Ground State ◽  
State Transition ◽  
Gamma Ray ◽  
The Other ◽  
Ground State Transition ◽  
Angular Correlations ◽  
First Excited State ◽  
Strong Ground

Levels at 6.69, 6.88, and 6.89 MeV were observed in the 16O(16O, α)28Si reaction, and angular correlations were measured for the resulting gamma-ray transitions, using the geometry in which the alpha particle is detected at 0°. The level at 6.69 MeV had not been reported previously and was assigned spin and parity 0+. The doublet of levels at 6.88–6.89 MeV was not resolved in these measurements, but angular correlations of the gamma-ray transitions were possible, using spectrum subtraction techniques. One member of the doublet, previously assigned spin 3, has a strong ground-state transition; the angular correlation for this transition confirms a 3− assignment to this level. The other member of the doublet, which decays almost entirely to the first excited state, could not be assigned a spin on the basis of these measurements. However, taken in conjunction with other measurements, an assignment of 4+ is favored.

Gamma Ray Angular Correlation in the Inelastic Scattering of Medium Energy Protons from the First Excited State of12C

1962 ◽  
Vol 79 (1) ◽  
pp. 14-26 ◽  
Author(s):  
G L Salmon ◽  
A B Clegg ◽  
K J Foley ◽  
P S Fisher ◽  
D J Rowe
Keyword(s):  
Excited State ◽  
Inelastic Scattering ◽  
Angular Correlation ◽  
Gamma Ray ◽  
Medium Energy ◽  
First Excited State

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.

GAMMA-RAY ANGULAR CORRELATIONS FROM ALIGNED NUCLEI PRODUCED BY NUCLEAR REACTIONS

1961 ◽  
Vol 39 (6) ◽  
pp. 788-824 ◽  
Author(s):  
A. E. Litherland ◽  
A. J. Ferguson
Keyword(s):  
Angular Correlation ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Nuclear Reactions ◽  
Residual Nucleus ◽  
Incident Beam ◽  
Nuclear Spectroscopy ◽  
Population Parameters ◽  
Axially Symmetric ◽  
Angular Correlations

Two general procedures for the measurement and analysis of angular correlations of gamma radiations from nuclear reactions are described which have wide applications in nuclear spectroscopy for the determination of spins and gamma-ray multipolarities. Cases can be studied by these methods when the reaction proceeds through a compound state too complex to allow the usual analysis to be made, for example where several levels overlap or where direct interaction is dominant. The basis of these procedures is to exploit the simplifications brought about by making the reacting system axially symmetric. A sharp gamma-ray-emitting state formed in such a system can be regarded as aligned and described in terms of a relatively small number of population parameters for the magnetic substates. In the first procedure, a state Y* is prepared by a nuclear reaction X(h1h2) Y* in which h2 is unobserved. The state Y* has axial symmetry about the beam axis. From coincidence angular correlation measurements of two cascade gamma rays from Y*, the unknown population parameters for Y* together with the nuclear spins and gamma-ray multipolarities can be determined. In the second procedure, h2 is measured in a small counter at 0° or 180° relative to the incident beam. It is then shown that the quantum numbers of the magnetic substates of Y* which can be populated do not exceed the sum of the spins of X, h1, and h2. In cases where the sum of the spins does not exceed [Formula: see text], the angular correlation of the gamma rays from the aligned state depends only upon the properties of the states in the residual nucleus. Theoretical expressions for angular correlations from aligned states are given, together with a method whereby existing extensive tables of coefficients can be used to calculate them. The results of two recent experiments are discussed as examples.

AN ILLUSTRATION OF A TYPE OF TRIPLE CORRELATION MEASUREMENT WHICH CAN BE EASILY INTERPRETED

1960 ◽  
Vol 38 (7) ◽  
pp. 927-940 ◽  
Author(s):  
A. E. Litherland ◽  
G. J. McCallum
Keyword(s):  
Angular Correlation ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Residual Nucleus ◽  
Incident Beam ◽  
Electric Quadrupole ◽  
Final States ◽  
Angular Correlations ◽  
Mixing Ratios ◽  
Triple Correlation

The Mg26(He4, nγ)Si29 reaction has been used to illustrate the simplifications introduced in the interpretation of triple angular correlations by choosing a target and bombarding particles of zero spin and by observing the emitted particles, in this case neutrons, in a counter fixed at 0° to the beam. The angular correlations of the gamma rays with respect to the incident beam then depend only upon the properties of the final states in the residual nucleus. The angular correlation of the electric quadrupole 2.03-Mev gamma ray is predicted uniquely by theory and this prediction has been verified experimentally. The angular correlations of the 1.28-Mev and 2.43-Mev gamma rays have yielded for the E2/M1 amplitude mixing ratios +0.25 ± 0.05 or −3.4 ± 0.5 and −0.26 ± 0.08 or −1.10 ± 0.16 respectively. In addition, the experiment provides an illustration of the value of the recently discovered technique of neutron – gamma-ray discrimination in an organic scintillator.

NUCLEAR g FACTOR OF THE FIRST EXCITED STATE IN 106Pd AND THE INTERNAL FIELD ON PALLADIUM IN NICKEL

1967 ◽  
Vol 45 (5) ◽  
pp. 1813-1819 ◽  
Author(s):  
J. Murray ◽  
T. A. McMath ◽  
J. A. Cameron
Keyword(s):  
Excited State ◽  
Room Temperature ◽  
Internal Field ◽  
Cobalt Alloys ◽  
G Factor ◽  
Angular Correlations ◽  
Perturbed Angular Correlations ◽  
First Excited State

The nuclear g factor of the first excited state in 106Pd has been measured by the method of perturbed angular correlations. The perturbing fields used were the internal fields on palladium in dilute iron and cobalt alloys. By comparing the rotation caused by these alloys with the rotation observed when nickel was the host, a measurement of the internal field on palladium in nickel has been obtained.The g factor of the first excited state in 106Pd has been determined to be +0.35 ± 0.03. The internal field on palladium in nickel at room temperature was found to be −174 ± 13 kOe.

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.

EXCITED STATES OF O18 STUDIED BY THE REACTION

1961 ◽  
Vol 39 (2) ◽  
pp. 276-294 ◽  
Author(s):  
A. E. Litherland ◽  
R. Batchelor ◽  
A. J. Ferguson ◽  
H. E. Gove
Keyword(s):  
Excited States ◽  
Gamma Rays ◽  
Recent Experiment ◽  
Gamma Ray ◽  
Electric Quadrupole ◽  
Angular Correlations ◽  
Small Admixture ◽  
First Excited State ◽  
Cascade Transition ◽  
Crossover Transition

Gamma rays from the excited states of O18 at 3.63 and 3.92 Mev have been observed using the reaction [Formula: see text] at an incident O16 energy of 14 Mev. Both states were observed to emit gamma rays to the 1.98-Mev 2+ first excited state of O18. No evidence for crossover transitions was found and in each case the crossover transition was estimated to be [Formula: see text] of the cascade transition. Angular correlations of the gamma rays were obtained and these strongly support an assignment of spin 0 to the 3.63-Mev state and a spin of 2 for the 3.92-Mev state. These assignments have been confirmed by a recent experiment on the O16(H3, p)O18 reaction which gives the assignments 0+ and 2+ for these two states. Thus the states at 3.55, 3.63, and 3.92 Mev form a triplet with assignments 4+, 0+, and 2+ which strongly resembles the vibrational spectra found in heavier nuclei. However, the measured angular correlations of the gamma rays from the 3.92-Mev state show only a small admixture of electric quadrupole in the 1.94-Mev gamma ray with relative amplitude +0.1 ±.1. A lower limit of ~10−12 seconds on the lifetime of the 3.63-Mev state was obtained from the absence of a doppler shift of the 1.65-Mev cascade gamma ray.

Observation of the 2159-keV level in 60Ni following the beta decay of 60Co

1970 ◽  
Vol 48 (5) ◽  
pp. 483-488 ◽  
Author(s):  
W. R. Dixon ◽  
R. S. Storey
Keyword(s):  
Excited State ◽  
Beta Decay ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Escape Peak ◽  
First Excited State

A search has been made with a Ge(Li) detector for weak gamma-ray transitions in 60Ni following the beta decay of 60Co. Observation of a gamma ray of energy 2158.8 ± 0.4 keV and intensity of about 10−5 per disintegration has confirmed that the 2159-keV level of 60Ni is populated in about 10−4 of the disintegrations. A much stronger peak at 822 keV has been shown to be the single-escape peak of the 1332-keV gamma ray rather than the (2159 → 1332) transition as claimed by Hansen and Spernol. The search for other weak gamma rays in 60Ni was inconclusive, and the mechanism for feeding the 2159-keV level is not clear. As a byproduct of this investigation, the energy of the first excited state of 64Ni is found to be 1345.9 ± 0.3 keV.

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