DOI
10.11606/D.43.2015.tde-06072015-050254
Documento
Autor
Nome completo
Jeremias Garcia Duarte
E-mail
Área do Conhecimento
Data de Defesa
Imprenta
São Paulo, 2015
Gasques, Leandro Romero (Presidente)
Faria, Pedro Neto de
Título em inglês
Determination of the astrophysical S(E) factor for the 16O+16O reaction
Palavras-chave em inglês
astrophysical S-factor
fusion cross section
gamma spectroscopy
Resumo em inglês
This work aims to obtain the fusion excitation function for the 16O+16O system through gamma-spectroscopy measurements and gamma-charged particle coincidence, using the Saci-Perere system mounted at the end of the 30A beamline of the Open Laboratory of Nuclear Physics of the University of São Paulo (LAFN). Tests with the gamma-charged particle detection system indicated its unfeasibility due to the short measurement time and lose of the neutron channel. To overcome this problem, a new experimental setup was used. Two $\gamma$-ray detectors were placed at 55º and 125º and a surface barrier detector was placed at 130º to monitor the 16O nuclei backscattered. The partial fusion cross sections related to the exit channels from the 16O+16O fusion reaction were measured by detecting their characteristic gamma rays at Ecm= 8.27, 9.27, 10.77 and 12.27 MeV. Three difficulties were faced during and after the experiment: carbon contamination of the target, natural background and low beam intensity. Efforts were made to successfully overcome these difficulties. The relative normalization was made by two ways, using the gamma-rays at 279 keV(197Au) and 536 keV(100Mo), and their results agree very well with each other. The total fusion cross section was obtained by summing the partial cross sections for each beam energy. Its absolute normalization was performed with the total theoretical fusion cross section obtained using coupled channel calculations, using the zero point motion model (ZPM), at Ecm= 12.27 MeV. With the total fusion cross section we calculated the astrophysical S-factor, and both results are in good agreement with the literature.
Título em português
Determinação do fator S(E) astrofísico para a reação 16O+16O
Palavras-chave em português
espectroscopia gama
fator S-astrofísico
seção de choque de fusão
Resumo em português