Experimental study of precisely selected evaporation chains in the decay of excited $^{25}$Mg

TL;DR

This study investigates the de-excitation of excited $^{25}$Mg nuclei produced in $^{12}$C + $^{13}$C reactions at 95 MeV, testing statistical decay models and comparing with $^{24}$Mg decay, revealing mostly good agreement with some deviations.

Contribution

It provides new experimental data on $^{25}$Mg decay chains, testing statistical models and comparing with $^{24}$Mg decay, highlighting similarities and deviations in evaporation processes.

Findings

Decay features mostly match statistical model predictions.

Deviations observed in alpha-particle evaporation chains.

Decay behavior of $^{25}$Mg similar to $^{24}$Mg.

Abstract

The reaction $^{12}$C + $^{13}$C at 95 MeV bombarding energy is studied using the GARFIELD + Ring Counter apparatus located at the INFN Laboratori Nazionali di Legnaro. In this paper we want to investigate the de-excitation of $^{25}$Mg aiming both at a new stringent test of the statistical description of nuclear decay and a direct comparison with the decay of the system $^{24}$Mg formed through $^{12}$C+$^{12}$C reactions previously studied. Thanks to the large acceptance of the detector and to its good fragment identification capabilities, we could apply stringent selections on fusion-evaporation events, requiring their completeness in charge. The main decay features of the evaporation residues and of the emitted light particles are overall well described by a pure statistical model; however, as for the case of the previously studied 24Mg, we observed some deviations in the branching ratios, in particular for those chains involving only the evaporation of $\alpha$ particles. From this point of view the behavior of the $^{24}$Mg and $^{25}$Mg decay cases appear to be rather similar. An attempt to obtain a full mass balance even without neutron detection is also discussed.