Angular Correlation of the Gamma Rays fromMn56

1953 ◽  
Vol 92 (4) ◽  
pp. 904-906 ◽  
Author(s):  
F. R. Metzger ◽  
W. B. Todd
Keyword(s):  
Angular Correlation ◽  
Gamma Rays

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.

Positron Annihilation in Teflon and Polyethylene

1974 ◽  
Vol 52 (11) ◽  
pp. 935-939 ◽  
Author(s):  
Donald P. Kerr
Keyword(s):  
Angular Distribution ◽  
Positron Annihilation ◽  
Angular Correlation ◽  
Gamma Rays ◽  
Momentum Distribution ◽  
Angular Distributions ◽  
Distribution Data ◽  
Lifetime Component ◽  
Considerable Uncertainty ◽  
Correlation Data

Both the time spectra and the angular distributions of the annihilation gamma rays have been measured for positrons annihilating in Teflon and polyethylene in an attempt to clarify which annihilation mechanisms account for the various lifetimes in these materials. Some authors have suggested that, in addition to the longest lifetime component, one of the shorter lived components also arises from the pickoff annihilation of orthopositronium. If this were the case, substantially more positronium would be formed than is indicated by the intensity of the longest lived component alone, and should be detectable through a measurement of the intensity of the low momentum portion of the momentum distribution obtained from the angular correlation data. In the present work, four lifetimes are apparent in the time spectra although there is considerable uncertainty in resolving the two shortest components. The angular distribution data, in both cases, yielded a low momentum component whose intensity indicates that only the longest lifetime component arises from pickoff annihilation of orthopositronium. The three shorter lifetime components are discussed.

Angular Correlation of the Gamma Rays ofBa134

1955 ◽  
Vol 99 (3) ◽  
pp. 691-694 ◽  
Author(s):  
M. G. Stewart ◽  
R. P. Scharenberg ◽  
M. L. Wiedenbeck
Keyword(s):  
Angular Correlation ◽  
Gamma Rays
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