1.1 本规程涵盖了酸性硫酸亚铁铵水溶液剂量测定系统的制备、测试和使用程序，以测量暴露于电离辐射时对水的吸收剂量。该系统由剂量计和适当的分析仪器组成。该系统将被称为弗里克剂量测定系统。Fricke剂量测定系统可用作参考标准剂量测定系统或常规剂量测定系统。 1.2 本规程是一套标准之一，为在辐射处理中正确实施剂量测定提供了建议，并描述了实现符合ISO/ASTM规程要求的方法 52628 用于Fricke剂量测定系统。应结合ISO/ASTM实践进行阅读 52628 . 1.3 本规程描述了弗里克剂量测定系统的分光光度分析程序。 1.4 这种做法仅适用于伽马辐射、X射线辐射（韧致辐射）和高能电子。 1.5 如果满足以下条件，则适用本规程: 1.5.1 吸收剂量范围应为20 Gy至400 Gy ( 1. ) . 2. 1.5.2 吸收剂量率不超过10 6. Gy·s −1 ( 2. ) . 1.5.3 对于放射性同位素伽马源，初始光子能量大于0.6MeV。对于X射线辐射（韧致辐射），用于产生光子的电子的初始能量等于或大于2MeV。 对于电子束，初始电子能量大于8 MeV。 注1: 给出的能量下限适用于直径为12mm的圆柱形剂量计安瓿。电子束可能需要对安瓿上的位移效应和剂量梯度进行校正 ( 3. ) 弗里克剂量测定系统可以通过使用更薄的（在射束方向上）剂量计容器以较低的能量使用（见ICRU报告35）。 1.5.4 剂量计的辐照温度应在10 °C至60 °C。 1.6 本标准并不旨在解决与其使用相关的所有安全问题（如有）。本标准的使用者有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.7 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。 ====意义和用途====== 4.1 Fricke剂量测定系统基于在酸性水溶液中通过电离辐射将亚铁离子氧化为铁离子的过程提供了用于测量对水的吸收剂量的可靠手段（ICRU 80、PIRS-0815， ( 4. ) ). 在不需要追溯到国家标准的情况下，该系统可用于吸收剂量的绝对测定，无需校准，因为铁离子的辐射化学产率具有良好的特征（见 附录X3 ). 4.2 剂量计是硫酸亚铁或硫酸亚铁铵的空气饱和溶液，通过在特定波长下增加光吸收率来指示吸收剂量。使用温度控制的校准分光光度计来测量吸光度。

1.1 This practice covers the procedures for preparation, testing, and using the acidic aqueous ferrous ammonium sulfate solution dosimetry system to measure absorbed dose to water when exposed to ionizing radiation. The system consists of a dosimeter and appropriate analytical instrumentation. The system will be referred to as the Fricke dosimetry system. The Fricke dosimetry system may be used as either a reference standard dosimetry system or a routine dosimetry system. 1.2 This practice 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 Fricke dosimetry system. It is intended to be read in conjunction with ISO/ASTM Practice 52628 . 1.3 The practice describes the spectrophotometric analysis procedures for the Fricke dosimetry 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 are satisfied: 1.5.1 The absorbed dose range shall be from 20 Gy to 400 Gy ( 1 ) . 2 1.5.2 The absorbed dose rate does not exceed 10 6 Gy·s −1 ( 2 ) . 1.5.3 For radioisotope gamma sources, the initial photon energy is greater than 0.6 MeV. For X-radiation (bremsstrahlung), the initial energy of the electrons used to produce the 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 given are appropriate for a cylindrical dosimeter ampoule of 12 mm diameter. Corrections for displacement effects and dose gradient across the ampoule may be required for electron beams ( 3 ) . The Fricke dosimetry system may be used at lower energies by employing thinner (in the beam direction) dosimeter containers (see ICRU Report 35). 1.5.4 The irradiation temperature of the dosimeter should be within the range of 10 °C to 60 °C. 1.6 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 4.1 The Fricke dosimetry system provides a reliable means for measurement of absorbed dose to water, based on a process of oxidation of ferrous ions to ferric ions in acidic aqueous solution by ionizing radiation (ICRU 80, PIRS-0815, ( 4 ) ). In situations not requiring traceability to national standards, this system can be used for absolute determination of absorbed dose without calibration, as the radiation chemical yield of ferric ions is well characterized (see Appendix X3 ). 4.2 The dosimeter is an air-saturated solution of ferrous sulfate or ferrous ammonium sulfate that indicates absorbed dose by an increase in optical absorbance at a specified wavelength. A temperature-controlled calibrated spectrophotometer is used to measure the absorbance.