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Electron-gamma directional correlations; Correlations directionnelles electron-gamma

Abstract

The theory of the angular correlation between conversion electrons and gamma rays is briefly outlined. The experimental methods used for the study of the electron-gamma correlation are described. The effects of the formation of a hole and the hyperfine structure magnetic coupling dependent on time are then considered. The experimental results showed that the attenuations found for different metallic media plainly conform to a simple quadrupolar interaction mechanism. For a source surrounded by an insulator, however, the results show that a rapidly disappearing coupling occurs as a supplement to the quadrupolar interaction mechanism. This coupling attenuates the angular correlation by about 75% of the non-perturbed value. It was concluded that for an intermediate half life of the level of the order of the nanosecond, the attenuations produced by the secondary effects of the hole formation can not be completely neglected. The metallic media considered were Ag, Au, Al, and Ga. In the study of E2 conversion processes, the radical matrix elements governing the E2 conversion process in the 412-KeV transition of {sup 198}Hg were determined. The results exclude the presence of dynamic contributions within the limits of experimental error. The values b{sub 2} (E2) and {alpha}-k (E2) obtained indirectly from  More>>
Authors:
Gerholm, T R [1] 
  1. Commissariat a l'Energie Atomique, Centre d'Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France)
Publication Date:
Oct 01, 1966
Product Type:
Technical Report
Report Number:
CEA-R-3025
Resource Relation:
Other Information: 78 refs; PBD: Oct 1966
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ANGULAR CORRELATION; COINCIDENCE SPECTROMETRY; ENERGY LEVELS; ENERGY-LEVEL TRANSITIONS; GAMMA DECAY; INTERNAL CONVERSION; MERCURY 198; TANTALUM 181; THALLIUM 201; THALLIUM 203
OSTI ID:
20468571
Research Organizations:
Commissariat a l'Energie Atomique, Centre d'Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France)
Country of Origin:
France
Language:
French
Other Identifying Numbers:
TRN: FR04R3025044281
Availability:
Available from INIS in electronic form
Submitting Site:
FRN
Size:
[50] pages
Announcement Date:

Citation Formats

Gerholm, T R. Electron-gamma directional correlations; Correlations directionnelles electron-gamma. France: N. p., 1966. Web.
Gerholm, T R. Electron-gamma directional correlations; Correlations directionnelles electron-gamma. France.
Gerholm, T R. 1966. "Electron-gamma directional correlations; Correlations directionnelles electron-gamma." France.
@misc{etde_20468571,
title = {Electron-gamma directional correlations; Correlations directionnelles electron-gamma}
author = {Gerholm, T R}
abstractNote = {The theory of the angular correlation between conversion electrons and gamma rays is briefly outlined. The experimental methods used for the study of the electron-gamma correlation are described. The effects of the formation of a hole and the hyperfine structure magnetic coupling dependent on time are then considered. The experimental results showed that the attenuations found for different metallic media plainly conform to a simple quadrupolar interaction mechanism. For a source surrounded by an insulator, however, the results show that a rapidly disappearing coupling occurs as a supplement to the quadrupolar interaction mechanism. This coupling attenuates the angular correlation by about 75% of the non-perturbed value. It was concluded that for an intermediate half life of the level of the order of the nanosecond, the attenuations produced by the secondary effects of the hole formation can not be completely neglected. The metallic media considered were Ag, Au, Al, and Ga. In the study of E2 conversion processes, the radical matrix elements governing the E2 conversion process in the 412-KeV transition of {sup 198}Hg were determined. The results exclude the presence of dynamic contributions within the limits of experimental error. The values b{sub 2} (E2) and {alpha}-k (E2) obtained indirectly from the experimentally determined b{sub 4} particle parameter are in complete agreement with the theoretical values obtained by applying the corrections due to the shielding effect and to the finite dimension of the nucleus and excluding the dynamic contributions. The value for the internal conversion coefficient was also in good agreement. Experimental results from the intensity ratios between the peak and the continuum, however, seem to show significant deviations with respect to other experimental and theoretical values. There is good agreement between experimental and theoretical results on the internal conversion of {sup 203}Tl, {sup 201}Tl, and {sup 181}Ta. The theory of internal conversion process containing the dynamic effects appears to be coherent and well understood. The penetration matrix effects can then be used as independent and complementary sources of information for the study of problems on nuclear structure. (author) [French] Dans le premier chapitre, l'auteur demontre l'interet des correlations angulaires electrons de conversion-gamma en spectrometric nucleaire et souligne la presence ''d'elements de matrice de penetration'' et l'importance de corrections ''dynamiques'', causees par la dimension finie du noyau. Dans le chapitre 2, l'auteur expose les methodes experimentales pour l'etude de la correlation electron-gamma. Une etude comparative est faite entre la correlation angulaire electron de conversion-gamma et la correlation angulaire gamma-gamma. Il est demontre qu'une mesure simultanee de ces deux fonctions de correlation permet d'eliminer les facteurs d'attenuations dus a l'action des champs extranucleaires. Une etude complete de ces champs est menee dans le chapitre 3 avec, principalement, la mise en evidence des effets ''de trou'' correspondant a une interaction de structure hyperfine entre le spin du noyau et celui de son atome. Pour une periode du niveau intermediaire de l'ordre de la nanoseconde, les attenuations creees par la formation de trou ne peuvent pas etre negligees, chaque fois que les atomes radioactifs sont inclus dans un milieu isolant. Les experiences permettant la determination des coefficients b{sub 2}(E{sub 2}) et {alpha}{sub K}(E{sub 2}) du {sup 198}Hg sont decrits chapitre 4. Dans le chapitre 5, l'auteur applique la determination des elements de matrice de penetration dans le processus de conversion M{sub 1} a l'etude des problemes sur la structure nucleaire. Dans le chapitre 6 sont decrites des experiences mettant en evidence le mode de transition E{sub 0} en competition directe avec la conversion interne M{sub 1} et E{sub 2}. (auteur)}
place = {France}
year = {1966}
month = {Oct}
}