Statistical Analysis of Preequilibriumα-Particle Spectra and Possible Local Heating

It is shown that energy spectra of preequilibrium $\alpha$-particle emission in ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}$+${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ reactions are reproduced well by the statistical formula of Ericson when nuclear temperature is treated as a parameter depending on the emission angle. The resultant temperature shows monotonical decrease with increasing angles, indicating the cooling-down process of the associated composite system.