Radiation quantities: their inter-relationship

The recommendations made by the International Commission on Radiological Protection (ICRP) in their Report 60 and by the International Commission on Radiation Units and Measurements (ICRU) in their Report 47 mean some major changes in concepts of radiation quantities and have a strong impact on their inter-relationship. These changes predominantly affect neutrons. This work therefore concentrates on discussing these changes for neutrons. The new ICRP recommendations use different concepts for describing the radiation quality for primary limiting and operational quantities: radiation weighting factors are now introduced to determine the effective dose, whereas the well known quality factors are still recommended to determine operational quantities such as the ambient, the directional and the personal dose equivalent. This paper discusses the physics of these concepts and the physical and numerical inter-relationships of the radiation quantities for neutrons. This analysis is then used to suggest a revision of the numerical values of the radiation weighting factors which is believed to be in accordance with the original intentional of the ICRP and to restore practicable and safe numerical relations between primarily limiting and operational quantities. (author)