  Calculating the thermal diffusivity of solid materials is commonly carried
out using the laser flash experiment. This classical experiment considers a
small (usually thin disc-shaped) sample of the material with parallel front and
rear surfaces, applying a heat pulse to the front surface and recording the
resulting rise in temperature over time on the rear surface. Recently, Carr and
Wood [Int J Heat Mass Transf, 144 (2019) 118609] showed that the thermal
diffusivity can be expressed analytically in terms of the heat flux function
applied at the front surface and the temperature rise history at the rear
surface. In this paper, we generalise this result to radial unidirectional heat
flow, developing new analytical formulas for calculating the thermal
diffusivity for cylindrical shell and spherical shell shaped samples. Two
configurations are considered: (i) heat pulse applied on the inner surface and
temperature rise recorded on the outer surface and (ii) heat pulse applied on
the outer surface and temperature rise recorded on the inner surface. Code
implementing and verifying the thermal diffusivity formulas for both
configurations is made available.
