The Usage and Measure Chin of Air Kerma and Exposure

As Air Kerma has been commonly used in radiotherapy, radioprotection, and other fields in calibration dosemeters, the use of unit Exposure had been evidently reduced. Air Kerma has some advantages and convenient in usage comparable to Exposure both theoretically and practically. Consider about the possible uncertainties in establish primary standard and convert to absorbed dose to water in a suitable phantom shows start from Air Kerma primary standard is smaller then that of Exposure.