Level density and $\gamma$-ray strength in ${}^{27,28}$Si

Abstract

A method to extract simultaneously level densities and $\gamma$-ray transmission coefficients has for the first time been tested on light nuclei utilizing the ${}^{28}$Si(${}^3$He,$\alpha \gamma {)}^{27}$Si and ${}^{28}$Si(${}^3$He,${}^3$He'$\gamma {)}^{28}$Si reactions. The extracted level densities for ${}^{27}$Si and ${}^{28}$Si are consistent with the level densities obtained by counting known levels in the respective nuclei. The extracted $\gamma$-ray strength in ${}^{28}$Si agrees well with the known $\gamma$-decay properties of this nucleus. Typical nuclear temperatures are found to be $T\sim 2.4$ MeV at around 7 MeV excitation energy. The entropy gap between nuclei with mass number $A$ and $A\pm 1$ is measured to be $\delta S\sim 1.0k_B$, which indicates an energy spacing between single-particle orbitals comparable with typical nuclear temperatures.

Totally 17 pages, 11 figures

References in corpus (6)

• Gamma-ray strength function and pygmy resonance in rare earth nuclei
• Thermal and electromagnetic properties of 166-Er and 167-Er
• Level densities and $\gamma$-strength functions in ${}^{148,149}$Sm
• Entropy of thermal quasiparticles in nuclei
• Heat capacity and pairing transition in nuclei
• Model for pairing phase transition in atomic nuclei

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