Practice for use of the ethanol-chlorobenzene dosimetry system
ISO 51538:2009 covers the procedure for preparation, handling, testing, and use of the ethanol-chlorobenzene (ECB) 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. It is classified as a reference-standard dosimetry system and is also used as a routine dosimetry system.
ISO 51538:2009 describes the mercurimetric titration analysis as a standard readout procedure for the ECB dosimeter when used as a reference standard dosimetry system. Other readout methods (spectrophotometric, oscillometric) that are applicable when the ECB system is used as a routine dosimetry system are described.
ISO 51538:2009 applies provided the following conditions are satisfied.The absorbed dose range is between 10 Gy and 2 MGy for gamma radiation and between 10 Gy and 200 kGy for high current electron accelerators.The absorbed-dose rate is less than 106 Gy s−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 equal to or greater than 4 MeV.
The ECB system may be used at energies of incident electrons lower than 4 MeV by employing thinner (in the beam direction) dosimeters. The ECB system may also be used at X-ray energies as low as 120 kVp. However, in this range of photon energies the effect caused by the ampoule wall is considerable.The irradiation temperature of the dosimeter is within the range from −40�C to 80�C.
The effects of size and shape of the dosimeter on the response of the dosimeter can adequately be taken into account by performing the appropriate calculations using cavity theory.