1.1 This practice covers the preparation, testing, and procedure
for using the acidic aqueous silver dichromate dosimetry
system to measure absorbed dose to water when exposed to
ionizing radiation. The system consists of a dosimeter and
appropriate analytical instrumentation. For simplicity, the system
will be referred to as the dichromate system. The dichromate
dosimeter is classified as a type I dosimeter on the basis
of the effect of influence quantities. The dichromate system
may be used as either a reference standard dosimetry system or
a routine dosimetry system.
1.2 This document is one of a set of standards that provides
recommendations for properly implementing dosimetry in
radiation processing, and describes a means of achieving
compliance with the requirements of ISO/ASTM Practice
52628 for the dichromate dosimetry system. It is intended to be
read in conjunction with ISO/ASTM Practice 52628.
1.3 This practice describes the spectrophotometric analysis
procedures for the dichromate system.
1.4 This practice applies only to gamma radiation,
X-radiation/bremsstrahlung, and high energy electrons.
1.5 This practice applies provided the following conditions
are satisfied:
1.5.1 The absorbed dose range is from 2 × 103 to
5 × 104 Gy.
1.5.2 The absorbed dose rate does not exceed 600 Gy/pulse
(12.5 pulses per second), or does not exceed an equivalent dose
rate of 7.5 kGy/s from continuous sources (1).2
1.5.3 For radionuclide gamma sources, the initial photon
energy shall be greater than 0.6 MeV. For bremsstrahlung
photons, the initial energy of the electrons used to produce the
bremsstrahlung photons shall be equal to or greater than 2
MeV. For electron beams, the initial electron energy shall be
greater than 8 MeV.