Summary
The three-body reaction11B(p, αα)4He has been studied at 20 MeV incident energy and at different angular configurations with the aim of investigating the different reaction mechanisms. Coincidence measurements between two of the α-particles have been performed at the 73°/73°, 73°/83° and 23°/137° configurations in a planar kinematics. The results show the contribution of the sequential two-step process11B(p, α)8Be* → α + α proceeding through the8Be ground state and its first excited levels and the presence of a quasi-free process involving the virtual7Li(p, α)4He reaction in the framework of the α-7Li cluster structure of11B.
Riassunto
La reaziono a 3 corpi11B(p, αα)4He è stata studiata ad un’energia incidente di 20 MeV ed in diverse configurazioni angolari per investigate i possibili meccanismi di reazione. Sono state effettuate misure di coincidenza α-α nelle configurazioni 73°/73°, 73°/83° e 23°/137° in cinematica planare. I risultati mostrano il contributo del processo sequenziale11B(p, α)8Be → α + α clle procede attraverso la formazione del8Be nel suo stato fondamentale o nei suoi primi stati eccitati nonché la presenza di un processo quasi libero che avviene tramite la reazione virtuale7Iii(p, α)4He descrivibile nel contesto della struttura ad ammasso possibile α-7Li del11B.
Резюме
Исследуется трехчастичная реакция11В(р, аа)4He при энергии падающего протона 20 МэВ и при различных угловых конфигурациях с целью изучения различных механизмов реакции. Проводятся измерения совпадений между двумя а-частицами при конфигурациях 73°/73°, 73°/83° и 237137° в плоской кинематике. Полученные результаты обнаруживают вклад последовательного двухступенчатого процесса11В(р, α)8Ве* → а+α, происходящего через основное состояние8Be и его первые возбужденные уровни, и наличие квазисвободного процесса, включающего виртуальную реакцию7Li(p, α)4He в рамках α-7Li кластерной структуры11В.
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References
F. Ajzenberg-Selove andT. Lauritsen:Nucl. Phys. A,227, 1 (1974).
L. Marquez, J. P. Laugier, R. Ballini, C. Lemeille, N. Saunier andJ. Rey:Nucl. Phys. A,97, 321 (1967);Y. S. Chen, S. T. Emerson, W. R. Jeackson, W. D. Simpson andG. C. Phillips:Nucl. Phys. A,106, 1 (1968);D. Kong-A-Siou andA. Giorni:Nucl. Phys. A,174, 312 (1971).
J. L. Quebert andL. Marquez:Nucl. Phys. A,126, 646 (1969).
J. Hudomalj, B. Antolković, K. Schafer andV. Valković:Nucl. Phys. A,186, 200 (1972).
V. Valcovic, D. Miljanić, R. B. Liebert andG. C. Phillips:Nucl. Phys. A,239, 260 (1975).
P. M. Cockburn, L. J. B. Goldfarb, I. S. Grant andH. E. Reed:Nucl. Phys. A,141, 532 (1970).
M. Lattuada, F. Riggi, S. Barbarino, C. Spitaleri andD. Vinciguerra:Lett. Nuovo Cimento,20, 193 (1977).
P. C. Young, P. D. Forsyth andJ. B. Marion:Nucl. Phys. A,91, 209 (1967).
L. B. Geesaman, H. B. Knowles andJ. B. Mead:Nucl. Phys.,88, 177 (1966).
P. Gil, L. Marquez, J. L. Quebert andH. Sztark:J. Phys. (Paris),33, 315 (1972).
M. M. Block:Phys. Rev.,101, 796 (1956);T. H. Berlin andG. E. Owen:Nucl. Phys.,5, 669 (1958).
P. G. Fallica, F. Riggi, C. Spitaleri andC. M. Sutera:Lett. Nuovo Cimento,22, 547 (1977).
N. S. Chant andP. G. Roos:Phys. Rev. C,15, 57 (1977).
V. Valković, C. Joseph, A. Niiler andG. C. Phillips:Nucl. Phys. A,116, 497 (1968).
D. R. Maxson:Phys. Rev.,128, 1321 (1962).
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Work supported in part by Istituto Nazionale di Fisica Nucleare and by Centro Siciliano di Fisica Nucleare e di Struttura della Materia.
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Lattuada, M., Riggi, F., Spitaleri, C. et al. Investigation of the reaction mechanisms in the11B+p → 3α Reaction at 20 MeV. Nuov Cim A 62, 165–174 (1981). https://doi.org/10.1007/BF02770908
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DOI: https://doi.org/10.1007/BF02770908