Re: Conversion: millirad/hr to uR/hr -Reply

[Charles Willis <CAW@nrc.gov>]

Tord,

The relationships between the various dose and exposure get complicated for low
photon energies.  Your conversion coefficient of 1 R = 0.96 rad is good for the dose
to a "small volume of tissue".  For photon energies above 0.1 MeV, it is within a
factor of two or less for the doses of interest in health physics.  For 0.01 MeV
photons, your conversion factor overestimates the effective dose equivalent by
about a factor of 100.  For the low-energy photons, there are differences between
the various doses;  the "deep dose equivalent" may be three or more times the
"effective dose equivalent."  The instrument response also is open to question at
low energies.  It is important to know what photon energies you are dealing with.

Charlie Willis
caw@nrc.gov