DEVELOPMENT OF A NEW SECONDARY STANDARD FOR H*(10).

A secondary standard for ambient dose equivalent, H*(10), is necessary for the dissemination of the unit Sievert (Sv), but there is no such standard commercially available currently. Furthermore, the measurement of H*(10) instead of calculating H*(10) from air kerma and conversion coefficients is needed for unknown radiation fields. We developed a prototype of a new secondary standard for H*(10) based on a spherical 1 l ionization chamber for air kerma.

CONVERSION COEFFICIENTS FROM AIR KERMA TO DIRECTIONAL DOSE EQUIVALENT H'(0.07) FOR PHOTONS.

New conversion coefficients from air kerma free-in-air, Ka, to directional dose equivalent at 0.07mm depth, H'(0.07), are provided for monoenergetic values and for the spectra of the radiation qualities defined in ISO 4037-1.

INFLUENCE OF NEW MASS ENERGY-ABSORPTION COEFFICIENTS FROM ICRU REPORT NO. 90 ON AIR KERMA TO DOSE EQUIVALENT CONVERSION COEFFICIENTS.

In Report No. 90 of the International Commission on Radiation Units and Measurements (ICRU), new mass energy-absorption coefficients are listed which are based on renormalized Scofield photoeffect cross-sections. The mass energy-absorption coefficients are the basis for the conversion coefficients from air kerma to the operational quantities listed in ISO 4037-3.