Time dependence of the thermal-photon thermometer

Abstract

A systematic study of the thermal-photon thermometer is presented for heavy-ion collisions at intermediate energies via the isospin-dependent quantum molecular dynamics model. We find that the duration of the thermal hard photons production is more than $500\phantom{\rule{0.28em}{0ex}}\mathrm{fm}/c$. The divergence between the initial temperature and the final measurement temperature is about 5%. The isospin dependence of the nuclear temperature is consistent between the initial temperature and the final measurement temperature. As a comparison, the slope and double-isotope ratio thermometers are also discussed.