Determination of the temperature of electromagnetically undercooled melts processed in a high vacuum by optical pyrometry is very limited owing to contamination of the optical viewing ports into the processing chamber. A new method for non-contacting, non-optical temperature measurement was investigated wit rrespect to its feasibility. Here, the energy distribution of the evaporating particles, which is of Maxwell-Boltzmann type, is determined by measuring the particle velocity distribution with the help of a time of flight (TOF) process and the particle masses with a quadrupole mass spectrometer. The first experimental results for a solid MnBi alloy agree well with theoretical predictions fitted to simultaneously determined thermocouple readings.