L. Colli Milazzo

Statistical multistep direct emission in the 120Sn(p, n) reaction

Abstract The SMDE is calculated using a p-h description of the excitation and a microscopic DWBA form factor for the inelastic scattering calculation. Up to six stages are calculated and good fitting of the experimental data is achieved.

Statistical multistep compound emission in the Al 27 ( He 3 , p ) Si 29 reaction

Excitation functions and angular distributions of protons emitted from the reaction /sup 27/Al(/sup 3/He,p)/sup 28/Si have been measured in the energy range from 9 to 14 MeV. Some of the excitation functions show the presence of fluctuations that can be attributed to the statistical multistep compound emission. This effect explains also the shape and absolute value of the emitted proton spectrum measured at 13 MeV incident /sup 3/He beam. This comparison yields the value of the strength of the residual two-body interaction.

Statistical multistep compound emission in the /sup 27/Al(/sup 3/He,p)/sup 29/Si reaction

Excitation functions and angular distributions of protons emitted from the reaction /sup 27/Al(/sup 3/He,p)/sup 28/Si have been measured in the energy range from 9 to 14 MeV. Some of the excitation functions show the presence of fluctuations that can be attributed to the statistical multistep compound emission. This effect explains also the shape and absolute value of the emitted proton spectrum measured at 13 MeV incident /sup 3/He beam. This comparison yields the value of the strength of the residual two-body interaction.

Investigation on possible cluster contribution to elastic scattering of protons by12C at different energies

SummaryThe elastic scattering of protons by12C has been analysed at energies from 3.0 to 61.4 MeV. The experimental data have been taken partly from the literature. The discrepancies between the predictions of the optical model and the experimental angular distributions are attributed to the presence of α-cluster structure in the target. We have evaluated, on the basis of a simple semi-classical model, a mean contribution of (19.5±2.0)% to the experimental elastic-scattering cross-section due to cluster structure. The mean distance between the alphas in12C, a free parameter in the model here proposed, has been evaluated under the hypothesis of symmetrical spatial configuration. Its mean value is (4.0±0.1) fm.RiassuntoÈ presentata un’analisi della diffusione elastica di protoni su12C per energie comprese tra 3.0 e 61.4 MeV. I dati sperimentali utilizzati sono stati in parte presi dalla letteratura. Le discrepanze fra le previsioni del modello ottico e le distribuzioni angolari sperimentali sono attribuite alla presenza di una struttura a cluster α del bersaglio. Sulla base di un semplice modello semiclassico è stato valutato un contributo medio del (19.5±2.0)% alla sezione d’urto sperimentale di diffusione elastica dovuto alla struttura a cluster. La distanza media tra le particelle alfa nel12C, parametro libero nel modello proposto, è stata valutata nell’ipotesi di una configurazione spaziale simmetrica. Il suo valore medio risulta di (4.0±0.1) fm.РезюмеАнализируется упругое рассеяние протонов на12С при энергиях от 3.0 до 61.4 МэВ. Экспериментальные данные частично берутся из литературы. Расхождения между предсказаниями оптической модели и экспериментальными угловыми распределениями приписываются наличию альфа-кластеров в мишени. На основе простой полуклассической модели мы оцениваем, что средний вклад (19.5±2.0)% в экспериментальное поперечное сечение упругого рассеяния обусловлен кластерной структурой. Предполагая симметричную пространственную конфигурацию, оценивается среднее расстояние между альфа-кластерами в12С которое представляет свободный параметр в предложенной модели. Эта величниа составляет (4.0±0.1) фм.