Published November 1963 | Version v1
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Contribution to the study of 12C excited levels resulting from the reactions 11B (P/ α0) and 11B (p, α1)

  • 1. Commissariat a l'Energie Atomique, Grenoble (France). Centre d'Etudes Nucleaires

Description

This work is made up of two parts. In the first part the differential cross-sections have been determined of the reactions 11B (p,α) from 130 to 500 keV thus confirming, at the 163 keV resonance, the (2+) characteristics of the 16.11 MeV level of 12C. Furthermore, the experimental results in the neighbourhood of the 163 keV resonance can be explained by the interference of the 12C levels: 2+ at 16.11 MeV and 1- at 17.23 MeV for the α0, 2+ at 16.11 MeV and 2- at 16.58 MeV for the α1. In the second part the (α-8Be) disintegration process of 12C has been studied in the neighbourhood of the 16.11 MeV level. It is shown that, if the (α-8Be) mode of disintegration is preponderant outside the Ep = 163 keV resonance, it is also preponderant at this same resonance; a direct disintegration of the 12C to 3 α, with an approximate magnitude of 40 per cent has however not been excluded. (author)

Availability note (English)

Available from INIS in electronic form

Abstract (French)

Ce travail comprend deux parties: Dans la premiere, on a determine la section efficace differentielle des reactions 11B (p,α) de 130 a 500 keV, confirmant, a la resonance de 163 keV, les caracteristiques (2+) du niveau de 16,11 MeV du 12C. En outre, les resultats experimentaux au voisinage de la resonance de 163 keV sont explicables par l'interference des niveaux du 12C: 2+ a 16,11 MeV et 1- a 17,23 MeV pour les α0, 2+ a 16,11 MeV et 2- a 16,58 MeV pour les α1. Dans la deuxieme partie, on a etudie le mode de desintegration (α-8Be) du 12C au voisinage du niveau de 16,11 MeV. On a montre que, si le mode de desintegration (α-8Be) est preponderant en dehors de la resonance Ep = 163 keV, il est egalement preponderant a cette resonance; une desintegration directe en 3α du 12C, dont l'ordre de grandeur maximum serait de 40 pour cent, n'a cependant pas pu etre exclue. (auteur)

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Additional details

Additional titles

Original title (French)
Contribution a l'etude des niveaux excites du

Publishing Information

Imprint Pagination
76 p.
Report number
CEA-R--2416

Optional Information

Notes
28 refs.