Generally, in the laser flash technique, thermal diffusivity of any sample is calculated using the t1/2 value obtained by analyzing the transient signal. The t1/2 value, and thus the thermal diffusivity obtained in this way, will have a good amount of scatter in the data at low temperatures due to the weak signal and the pick up of external noise during the measurement. This necessitated suitable modifications in the data acquisition system to enhance the signal-to-noise ratio for the measurements carried out at low temperatures. This article presents the necessary modifications made in the existing data acquisition system. The measurements of thermal diffusivity of stainless-steel samples by the laser flash method and their results are discussed here. © 2002 American Institute of Physics.