This report is based on an experimental study on the energy of alpha particles that were emitted by a triple-alpha sources named Cmin a chamber that has a diffused p-i-n detector and measure the alpha particle properties at different pressures. Properties of these alpha-particles and the radioactive particles of some minor corrections to the biggest transaction of certain productivity and the radioisotopes, which include; absolute activities, peak energies, ranges, intensity and energy straggling, were all investigated. The results of the absolute activities for the radioisotopes in the alpha sources were; respectively. Different peak energies of the triple alpha-particles were observed to have similar shape as predicted by the radioisotopes decay scheme. Experimentally, the ranges of the triple alpha particles were found to be as follows; respectively at standard temperature and pressure.As the air pressure increases, the intensity of the triple alpha peaks decreases and the energy straggling which caused the increase in widths of the alpha peaks were observed.