By radiation dosimetry, we will mean the determination of the energy deposited per unit mass of irradiated material by ionizing radiation. Usually the material of interest in tissue and the results are to be applied to a radiobiological experiment, a radiotherapy treatment, or the protection of personnel from radiation hazards. The same methods, however, are applied to such engineering problems as the production of heat by reactor radiations, the use of radiation in chemical reactions or food processing, etc.