Abstract
Detailed numerical studies are made of recent measurements by Sumita and Takahashi of average and most probable slowing down times to thermal energies in graphite. Good agreement is obtained between computed and measured values at 52, 491, 146, 028, 20 and 11 eV. Similar studies are successfully made of the lead slowing down time spectrometer for a variety of detectors covering the energy range 1 to 3 keV. Estimates are made of the effects of data uncertainties on the theoretical values.