The stopping power and straggling for alpha particles in liquids

A silicon semiconductor detector spectrometer for the study of stopping power and straggling for alpha particles in liquids is described. The absolute thickness of the liquid layer has been measured using a Michelson Interferometer and a micrometer, the experimental set-up having been kept in a temperature-controlled room. A specially designed collimator houses the alpha particle source (Cm - 244) employed for the measurements in water and a tissue-equivalent liquid. Range-energy and stopping power curves for water and the tissue-equivalent liquid have been presented. Range of 5.3 MeV (Po - 210) alpha particles in water has been estimated to be 40 μm and compared with Aniansson's results. Finally, range-energy data for the tissue-equivalent liquid and a tissue-equivalent gas (Rossi) have been presented after normalising to tissue; the mean stopping power in the tissue-equivalent liquid is estimated to be 7% lower than that in the gas for alpha particles of energy 4.47 MeV to 0.175 MeV