scope:

This practice covers the procedures for preparation, testing, and using the ceric-cerous sulfate dosimetry system to determine absorbed dose (in terms of absorbed dose to water) in materials irradiated by photons (gamma radiation or X-radiation/bremsstrahlung) or high-energy electrons. The system consists of a dosimeter and appropriate analytical instrumentation. For simplicity, the system will be referred to as the ceric-cerous system. It is classified as a reference-standard dosimetry system (see ISO/ASTM Guide 51261). Ceric-cerous dosimeters are also used as transfer-standard dosimeters or routine dosimeters.

This practice describes both the spectrophotometric and the potentiometric readout procedures for the ceric-cerous system.

This practice applies provided the following conditions are satisfied:

The absorbed-dose range is between 0.5 and 50 kGy (1).²

The absorbed-dose rate is less than 10⁶ Gy s⁻¹(1).

For radionuclide gamma-ray sources, the initial photon energy is greater than 0.6 MeV. For bremsstrahlung photons, the energy of the electrons used to produce the bremsstrahlung photons is equal to or greater than 2 MeV. For electron beams, the initial electron energy is greater than 8 MeV.

NOTE 1-The lower energy limits are appropriate for a cylindrical dosimeter ampoule of 12-mm diameter. Corrections for dose gradients across an ampoule of that diameter or less are not required for photons, but may be required for electron beams (2). The ceric-cerous system may be used at lower energies by employing thinner (in the beam direction) dosimeters.

The irradiation temperature of the dosimeter is above 0°C and below 62°C (3).

NOTE 2-The temperature dependence of dosimeter response is known only in this range (see 4.3). Use outside this range requires determination of the temperature dependence.

This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

² The boldface numbers in parentheses refer to the bibliography at the end of this standard.