1.1 本规程涵盖了使用硫酸铈-硫酸铈剂量测定系统测量暴露于电离辐射时对水的吸收剂量的准备、测试和程序。该系统由剂量计和适当的分析仪器组成。为简单起见，该系统将被称为铈铈系统。根据影响量的影响，铈剂量计被归类为1型剂量计。铈铈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 本文件是一套标准之一，提供了在辐射处理中正确实施剂量测定的建议，并描述了实现符合ISO/ASTM实践要求的方法 52628 对于铈铈系统。本手册旨在结合ISO/ASTM惯例阅读 52628 . 1.3 本规程描述了铈-铈系统的分光光度法和电位读出程序。 1.4 本规程仅适用于伽马辐射、X辐射/韧致辐射和高能电子。 1.5 只要满足以下条件，本规程适用: 1.5.1 吸收剂量范围为5×10 2. 至5×10 4. 戈瑞 ( 1. ) . 2. 1.5.2 吸收剂量率不超过10 6. Gy s公司 −1. ( 1. ) . 1.5.3 放射性核素γ- 射线源，初始光子能量大于0.6MeV。对于韧致辐射光子，用于产生韧致辐射光子的电子的初始能量等于或大于2 MeV。对于电子束，初始电子能量大于8MeV。 注1: 能量下限适用于直径为12 mm的圆柱形剂量计安瓿。电子束可能需要校正安瓿上的剂量梯度 ( 2. ) . 通过使用更薄的（束流方向）剂量计，可以在较低能量下使用铈-铈系统（见ICRU报告35）。 1.5.4 剂量计的辐照温度高于0°C，低于62°C ( 3. ) . 注2: 剂量计响应的温度系数仅在此范围内已知（参见 5.2 ). 在该范围外使用需要测定温度系数。 1.6 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全和健康实践，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（TBT）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》中确立的国际公认标准化原则制定的。 ====意义和用途====== 4.1 铈铈系统为测定水的吸收剂量提供了可靠的方法。它基于通过电离辐射将酸性水溶液中的铈离子还原为铈离子的过程 ( 1. , 4. ，ICRU报告80） . 注3: 实践中描述的铈-铈系统将硫酸铈添加到初始溶液中，以减少有机杂质的影响，并允许采用电位法测量。用于剂量测定的其他系统包括硫酸铈或硫酸铈铵在硫酸中的溶液，无需初始添加硫酸铈。 这些其他系统基于将铈离子还原为铈离子的相同过程，但不包括在本实践中。

1.1 This practice covers the preparation, testing, and procedure for using the ceric-cerous sulfate 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 ceric-cerous system. The ceric-cerous dosimeter is classified as a type 1 dosimeter on the basis of the effect of influence quantities. The ceric-cerous system may be used as a reference standard dosimetry system or as 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 ceric-cerous system. It is intended to be read in conjunction with ISO/ASTM Practice 52628 . 1.3 This practice describes both the spectrophotometric and the potentiometric readout procedures for the ceric-cerous 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 5 × 10 2 to 5 × 10 4 Gy ( 1 ) . 2 1.5.2 The absorbed-dose rate does not exceed 10 6 Gy s −1 ( 1 ) . 1.5.3 For radionuclide gamma-ray sources, the initial photon energy is greater than 0.6 MeV. For bremsstrahlung photons, the initial 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 gradient across the ampoule 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 (see ICRU Report 35). 1.5.4 The irradiation temperature of the dosimeter is above 0°C and below 62°C ( 3 ) . Note 2: The temperature coefficient of dosimeter response is known only in this range (see 5.2 ). Use outside this range requires determination of the temperature coefficient. 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 and health 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 ceric-cerous system provides a reliable means for determining absorbed dose to water. It is based on a process of reduction of ceric ions to cerous ions in acidic aqueous solution by ionizing radiation ( 1 , 4 , ICRU Report 80) . Note 3: The ceric-cerous system described in the practice has cerous sulfate added to the initial solution to reduce the effect of organic impurities and to allow the potentiometric method of measurement. Other systems used for dosimetry include solutions of ceric sulfate or ceric ammonium sulfate in sulfuric acid without the initial addition of cerous sulfate. These other systems are based on the same process of reduction of ceric ions to cerous ions but are not included in this practice.