Neutron RBE values and their relationship to judgements in radiological protection

This review traces the history of radiological protection judgements concerning the relative biological effectiveness (RBE) for neutrons and quality factor. The basis of the different views coming from the International Commission on Radiological Protection (ICRP) and the International Commission on Radiation Units and Measurements (ICRU) is explained. A review of present-day information on neutron RBE relevant to judgements for radiological protection purposes is presented. It is argued that variations in neutron RBE measurements are large so that for practical purposes pragmatic judgements need to be made. It is further suggested that no inconsistency arises if different judgements are made for different purposes. However, this would require some resolution of the contrasting views of ICRP and ICRU.