Measurement of polarization tensors in the heavy-ion induced reactions and its application to the study of the reactions of astrophysical interest

点击翻译按钮获取中文摘要

The present study aims to develop a new experimental method of determining the spin of the nuclcar states of astrophysical interest by measuring the polarization tensors of the nuclei produced by the heavy-ion induced transfer reactions. The polarization tensors are being planned to be measured with high efficiency by observing the angular and energy broadenings of the reaction products due to the recoil of the particle or γ-ray emission using the two-dimensional position-sensitive silicon semiconductor detectors. The energy and position responses of the one-dimensional silicon detector have been investigated for α particles from a^<241> Am source and for ^<11>B and ^<12>C particles with kinetic energies ranging from several MeV to several ten MeV, produced by the ^<11>B+^<12>C reaction. Good linearity with the detected position was obtained by applying the gated integrator for both the energy and position signals. Energy ballistic deficit was also found to be negligible. The investigation of the response of the two-dimensional position sensitive detector is in progress.It was most important, for establishing the reliable method to determine the nuclear spin, to verify that the contribution of the reaction mechanisms other than the one-step transfer is of crucial importance in the heavy-ion induced transfer reactions. The one-nucleon transfer reactions leading to ^<12>C[2^+_1] have been investigated using the kinematical coincidence method. The deduced fourth rank tensor of ^<12>C[2^+_1] was found to significantly deviate from zero value, contrary to the prediction of the one-step distorted-wave Born approximation theory.