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ISO/ASTM51401-02
Standard Practice for Use of a Dichromate Dosimetry System
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Сборник (ASTM):
12.02 Nuclear (II), Solar, and Geothermal Energy; Radiation Processing / Ядерная энергия (II), Солнечная, и Геотермическая Энергия; Радиационная обработка
Тематика:
Nuclear Technology
Описание
Область применения

1.1 This practice covers the preparation, testing, and procedurefor using the acidic aqueous silver dichromate dosimetry system tomeasure absorbed dose in water when exposed to ionizing radiation.The system consists of a dosimeter and appropriate analyticalinstrumentation. For simplicity, the system will be referred to asthe dichromate system. It is classified as a reference standarddosimetry system (see ISO/ASTM Guide 51261).

1.2 This practice describes the spectrophotometric analysisprocedures for the dichromate system.

1.3 This practice applies only to γ-rays, X rays, and highenergy electrons.

1.4 This practice applies provided the following conditions aresatisfied:

1.4.1 The absorbed dose range is from 2 X 10 3 to 5 X104 Gy.

1.4.2 The absorbed dose rate does not exceed 600 Gy/pulse with apulse repetition rate not to exceed 12.5 Hz, or does not exceed anequivalent dose rate of 7.5 kGy/s from continuous sources(1).

1.4.3 For radionuclide gamma-ray sources, the initial photonenergy shall be greater than 0.6 MeV. For bremsstrahlung photons,the initial energy of the electrons used to produce thebremsstrahlung photons shall be equal to or greater than 2 MeV. Forelectron beams, the initial electron energy shall be greater than 8MeV.

Note 1—The lower energy limits given are appropriate for acylindrical dosimeter ampoule of 12 mm diameter. Corrections fordisplacement effects and dose gradient across the ampoule may berequired for electron beams (2). The dichromate system maybe used at lower energies by employing thinner (in the beamdirection) dosimeter containers (see ICRU Report 35).



1.4.4 The irradiation temperature of the dosimeter shall beabove 0°C and should be below 80°C.

Note 2—The temperature coefficient of dosimeter response isknown only in the range of 5 to 50°C (see 10.1.8). Use outside thisrange is not recommended.

1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establishappropriate safety and health practices and determine theapplicability of regulatory limitations prior to use. Specificprecautionary statements are given in Note.