Transfer of the absorbed dose unit by ferrous sulphate dosemeter

To establish a coherent system of metrological references it is necessary in particular to define and employ transfer methods so that the knowledge can be reflected with minimum loss. In the field of ionizing radiation dosimetry it was necessary after the roentgen which is the unit of exposure, to develop transfer methods for the rad, absorbed dose unit. Without excluding other possibilities the method adopted is based on the use of the ferrous sulphate dosimeter, for standardized dosimetric conditions (geometry, medium) and in the users'own beams. The metrological characteristics of the ferrous sulphate dosimeter, were studied beforehand, especially the conservation of data in time and the yield G as a function of energy. The method proposed leads to the water-absorbed dose calibration of the user's dosimeter in his own beam, for X or γ photons of energies between about 0.5 and 1.5 MeV; for higher-energy photons and for 10 to 35 MeV electrons the same procedure is applicable as long as certain conventions (measurement depths and yield G of the transfer dosimeter) are adopted temporarily