Department of Physics

Production of alpha clusters during fusion

Abstract: While statistical emission of alpha particles from excited nuclei is a well-known phenomenon, it has recently been proposed that dynamical emission of alpha particles following fusion probes the density dependence of the nuclear equation-of-state. To investigate this topic requires determining when a fusion reaction occurs and measuring the coincident alpha emission.

When two nuclei fuse, a heavier nucleus called the compound nucleus is produced. This compound nucleus is excited and de-excites by emission of neutrons, protons, and alpha particles resulting in an evaporation residue (ER). The ER is distinguished from the unreacted beam by using an Energy Time-Of-Flight (ETOF) approach. Observation of the ER signals the occurrence of fusion.

Using the ETOF technique, an experiment to study “alpha clustering in the fusion of silicon nuclei” was conducted at Michigan State University’s ReA3 facility in March 2022. The goal of the experiment was to investigate α cluster emission associated with the fusion of ^28,30,32Si + ²⁸Si. To perform the measurement, the standard ETOF experimental setup previously used was augmented by four highly segmented Si-Si-CsI(Tl)/PD telescopes. These detectors provided an efficient measurement of the emitted protons and α particles. Experimental details will be described, and the preliminary analysis of the data will be presented.