Temperature determination from the lattice gas model

Determination of temperature from experimental data has become important in searches for critical phenomena in heavy-ion collisions. Widely used methods are ratios of isotopes (which rely on chemical and thermal equilibrium), population ratios of excited states, etc. Using the lattice gas model we propose a new observable: n(ch)/Z where n(ch) is the charge multiplicity and Z is the charge of the fragmenting system. We show that the reduced multiplicity is a good measure of the average temperature of the fragmenting system.