Realization of dose measurement in radiation protection

The dose quantities to be realized by primary standards and to be assessed by radiation protection instruments are discussed. For photons up to one MeV the 'exposure' will retain its prominent position only with regard to primary standards, for radiation protection field instruments the ICRU-concept of 'dose equivalent index' appears to be better suited. It may be approximated by measuring dose equivalents in two different depths. The design features of an instrument are outlined