4.1 The dichromate system provides a reliable means for measuring absorbed dose to water. It is based on a process of reduction of dichromate ions to chromic ions in acidic aqueous solution by ionizing radiation.4.2 The dosimeter is a solution containing silver and dichromate ions in perchloric acid in an appropriate container such as a sealed glass ampoule. The solution indicates absorbed dose by a change (decrease) in optical absorbance at a specified wavelength(s) ((3), ICRU Report 80). A calibrated spectrophotometer is used to measure the absorbance.1.1 This practice covers the preparation, testing, and procedure for using the acidic aqueous silver dichromate 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 dichromate system. The dichromate dosimeter is classified as a type I dosimeter on the basis of the effect of influence quantities. The dichromate system may be used as either a reference standard dosimetry system or 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 dichromate dosimetry system. It is intended to be read in conjunction with ISO/ASTM Practice 52628.1.3 This practice describes the spectrophotometric analysis procedures for the dichromate 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 2 × 10 3 to 5 × 104 Gy.1.5.2 The absorbed dose rate does not exceed 600 Gy/pulse (12.5 pulses per second), or does not exceed an equivalent dose rate of 7.5 kGy/s from continuous sources (1).21.5.3 For radionuclide gamma sources, the initial photon energy shall be greater than 0.6 MeV. For bremsstrahlung photons, the initial energy of the electrons used to produce the bremsstrahlung photons shall be equal to or greater than 2 MeV. For electron beams, the initial electron energy shall be 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 (2). The dichromate 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 shall be above 0°C and should be below 80°C.Note 2—The temperature coefficient of dosimeter response is known only in the range of 5 to 50°C (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. Specific precautionary statements are given in 9.3.

定价： 702元 / 折扣价： 597 元 加购物车

4.1 Food products may be treated with acceleratorgenerated radiation (electrons and X-rays) for numerous purposes, including control of parasites and pathogenic microorganisms, insect disinfestation, growth and maturation inhibition, and shelf-life extension. Food irradiation specifications almost always include a minimum or a maximum limit of absorbed dose, sometimes both: a minimum limit may be set to ensure that the intended beneficial effect is achieved and a maximum limit may be set for the purpose of avoiding product or packaging degradation. For a given application, one or both of these values may be prescribed by government regulations that have been established on the basis of scientific data. Therefore, prior to the irradiation of the food product, it is necessary to determine the capability of an irradiation facility to consistently deliver the absorbed dose within any prescribed limits. Also, it is necessary to monitor and document the absorbed dose during each production run to verify compliance with the process specifications at a predetermined level of confidence.NOTE 3 - The Codex Alimentarius Commission has developed an international General Standard and a Code of Practice that address the application of ionizing radiation to the treatment of foods and that strongly emphasize the role of dosimetry for ensuring that irradiation will be properly performed (1).44.2 For more detailed discussions of radiation processing of various foods, see Guides F 1355, F 1356, F 1736, and F 1885 and Refs (2-15).4.3 Accelerator-generated radiation can be in the form of electrons or X-rays produced by the electrons. Penetration of radiation into the product required to accomplish the intended effect is one of the factors affecting the decision to use electrons or X-rays.4.4 To ensure that products are irradiated within a specified dose range, routine process control requires routine product dosimetry, documented product handling procedures (before, during and after the irradiation), consistent orientation of the products during irradiation, monitoring of critical operating parameters, and documentation of all relevant activities and functions.1.1 This practice outlines the installation qualification program for an irradiator and the dosimetric procedures to be followed during operational qualification, performance qualification and routine processing in facilities that process food with high-energy electrons and X-rays (bremsstrahlung) to ensure that product has been treated within a predetermined range of absorbed dose. Other procedures related to operational qualification, performance qualification and routine processing that may influence absorbed dose in the product are also discussed. Information about effective or regulatory dose limits for food products, and appropriate energy limits for electron beams used directly or to generate X-rays is not within the scope of this practice (see ASTM Guides F 1355, F 1356, F 1736, and F 1885).Note 1Dosimetry is only one component of a total quality assurance program for adherence to good manufacturing practices used in the production of safe and wholesome food.Note 2ISO/ASTM Practice 51204 describes dosimetric procedures for gamma irradiation facilities for food processing.1.2 For guidance in the selection and calibration of dosimetry systems, and interpretation of measured absorbed dose in the product, see ISO/ASTM Guide 51261 and ASTM Practice E 666. For the use of specific dosimetry systems, see ASTM Practices E 1026 and E 2304, and ISO/ASTM Practices 51205, 51275, 51276, 51310, 51401, 51538, 51540, 51607, 51650 and 51956. For discussion of radiation dosimetry for electrons and X-rays also see ICRU Reports 35 and 14. For discussion of radiation dosimetry for pulsed radiation, see ICRU Report 34.1.3 While gamma radiation from radioactive nuclides has discrete energies, X-rays (bremsstrahlung) from machine sources cover a wide range of energies, from low values (about 35 keV) to the energy of the incident electron beam. For information concerning electron beam irradiation technology and dosimetry, see ISO/ASTM Practice 51649. For information concerning X-ray irradiation technology and dosimetry, see ISO/ASTM Practice 51608.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.

定价： 0元 / 折扣价： 0 元

4.1 The ECB dosimetry system provides a reliable means of measuring absorbed dose to water. It is based on a process of radiolytic formation of hydrochloric acid (HCl) in aqueous ethanolic solutions of chlorobenzene by ionizing radiation ((7, 8) , ICRU 80).4.2 The dosimeters are partly deoxygenated solutions of chlorobenzene (CB) in 96 volume % ethanol in an appropriate container, such as a flame-sealed glass ampoule. Radiation chemical yields (G) for the formation of HCl in typical ECB solution formulations are given in Table 1.(A) The ratio of the photon mass energy-absorption coefficients for water and the dosimeter solution at 60Co gamma ray energy:(B) Radiation chemical yield of HCl in the dose range from 100 Gy to 100 kGy.(C) Upper dose range 20 kGy.(D) Lower dose range 1 kGy. This formulation also contained 0.04 % acetone and 0.04 % benzene.4.3 The irradiated solutions indicate absorbed dose by the amount of HCl formed. A number of analytical methods are available for measuring the amount of HCl in ethanol (10) .4.4 The concentration of chlorobenzene in the solution can be varied so as to simulate a number of materials in terms of the photon mass energy-absorption coefficients (μen/ρ) for X- and gamma radiation, and electron mass collision stopping powers (S/ρ), over a broad energy range from 10−2 to 100 MeV (11-14).4.5 The ECB dosimetry system may be used with other radiation types, such as neutrons (15) , and protons (16). Meaningful dosimetry of any radiation types and energies novel to the system's use requires that the respective radiation chemical responses applicable under the circumstances be established in advance.1.1 This practice covers the preparation, handling, testing, and procedure for using the ethanol-chlorobenzene (ECB) 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 ECB system. The ECB dosimeter is classified as a type I dosimeter on the basis of the effect of influence quantities. The ECB dosimetry 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 ECB system. It is intended to be read in conjunction with ISO/ASTM Practice 52628.1.3 This practice 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 in Annex A1 and Annex A2.1.4 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 between 10 Gy and 2 MGy for gamma radiation and between 10 Gy and 200 kGy for high current electron accelerators (1, 2).2 (Warning—the boiling point of ethanol chlorobenzene solutions is approximately 80 °C. Ampoules may explode if the temperature during irradiation exceeds the boiling point. This boiling point may be exceeded if an absorbed dose greater than 200 kGy is given in a short period of time.)1.5.2 The absorbed-dose rate is less than 106 Gy s−1(2).1.5.3 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 (3).NOTE 1: The same response relative to 60Co gamma radiation was obtained in high-power bremsstrahlung irradiation produced by a 5 MeV electron accelerator (4).NOTE 2: The lower energy limits are appropriate for a cylindrical dosimeter ampoule of 12-mm diameter. Corrections for dose gradients across the ampoule may be required for electron beams. The ECB system may be used at lower energies by employing thinner (in the beam direction) dosimeters (see ICRU Report 35). The ECB system may also be used at X-ray energies as low as 120 kVp (5). However, in this range of photon energies the effect caused by the ampoule wall is considerable.NOTE 3: 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 (6).1.5.4 The irradiation temperature of the dosimeter is within the range from −30 °C to 80 °C.NOTE 4: The temperature dependence of dosimeter response is known only in this range (see 5.2). For use outside this range, the dosimetry system should be calibrated for the required range of irradiation temperatures.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. Specific warnings are given in 1.5.1, 9.2 and 10.2.1.7 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.

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4.1 Indicators may be used to show that products have been exposed to a radiation source. They should be used only to provide a qualitative indication of radiation exposure and may be used to distinguish process loads that have been irradiated from unirradiated loads.NOTE 1: The use of indicators does not eliminate the need for other process-control procedures, such as quantitative dosimetry or the controlled segregation of irradiated from nonirradiated products.NOTE 2: See ISO/ASTM Standards 51608, 51649, 51702, 51939, and 51940 for information on the use of indicators in the various types of processing facilities and for unique product applications.4.2 The indicator manufacturer is obliged to supply a statement regarding the approximate dose level at which the examiner (20/20 vision), at standard illumination (unfiltered daylight, or artificial light of the spectrum and intensity defined by the proper ASTM standard), is able to determine the visual change in the indicator.1.1 This document covers procedures for using radiation-sensitive indicators (referred to hereafter as indicators) in radiation processing. These indicators may be labels, papers, inks or packaging materials which undergo a visual change when exposed to ionizing radiation (1-5).21.2 The purpose for using indicators is to determine visually whether or not a product has been irradiated, rather than to measure different dose levels.1.3 Indicators are not dosimeters and should not be used as a substitute for proper dosimetry. Information about dosimetry systems for radiation processing is provided in other ASTM and ISO/ASTM documents (see ISO/ASTM Guide 51261).1.4 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.1.5 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.

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4.1 The radiochromic liquid dosimetry system provides a means of measuring absorbed dose in materials (5-7). Under the influence of ionizing radiation, chemical reactions take place in the radiochromic solution modifying the amplitudes of optical absorption bands (8-10). Absorbance values are measured at the selected wavelength(s) within these affected absorption bands (see also ISO/ASTM Guide 51261).4.2 In the use of a specific dosimetry system, a calibration curve or response function relates the dosimeter’s response to an absorbed dose traceable to a nationally or internationally recognized standard (11, 12).4.3 The absorbed dose that is measured is usually specified in water. Absorbed dose in other materials may be evaluated by applying the conversion factors discussed in ISO/ASTM Guide 51261.NOTE 2—For a comprehensive discussion of various dosimetry methods applicable to the radiation types and energies discussed in this practice, see ICRU Reports 14, 17, 34, 35, and 37.4.4 These dosimetry systems may be used in the industrial radiation processing of a variety of products, for example the sterilization of medical devices and radiation processing of foods (5, 7, 13).4.5 The available dynamic range indicated in 1.2.1 is achieved by using a variety of radiochromic leuco dyes (Table 1) in a variety of solutions (Table 2).<4.6 The ingredients of the solutions, in particular the solvents, can be varied so as to simulate a number of materials in terms of the photon mass energy-absorption coefficients, (μen/ρ), for X-rays and gamma-rays and electron mass collision stopping powers, [(1/ρ) dE/dx], over a broad spectral energy range from 0.01 to 100 MeV (18). For special applications certain tissue-equivalent radiochromic solutions have been designed to simulate various materials and anatomical tissues, in terms of values of (μen/ρ) for photons and [(1/ρ) dE/dx] for electrons (18) (see also ICRU Report 44). Tabulations of the values of (μen/ρ) for water (19), the anatomical tissues (17, 19), and three specially designed radiochromic solutions, for photons over the energy range from 0.01 to 20 MeV, and tabulations of the values of [(1/ρ) dE/dx] (17) for water, the tissues and the radiochromic solutions for electrons over the energy range from 0.01 to 20 MeV are given in Refs (12, 13, 18). For additional information see ISO/ASTM Guide 51261, ASTM Practice E 666, and ICRU Reports 14, 17, 35, 37, and 44.1.1 This practice covers the procedures for preparation, handling, testing, and using radiochromic liquid dosimetry systems of radiochromic dye solutions held in sealed or capped containers (for example, ampoules, vials). It also covers the use of spectrophotometric or photometric readout equipment for measuring absorbed dose in materials irradiated by photons and electrons.1.2 This practice applies to radiochromic liquid dosimeter solutions that can be used within part or all of the specified ranges as follows:1.2.1 The absorbed dose range is from 0.5 to 40 000 Gy for photons and electrons.1.2.2 The absorbed dose rate is from 10−3 to 1011 Gy/s.1.2.3 The radiation energy range for photons is from 0.01 to 20 MeV.1.2.4 The radiation energy range for electrons is from 0.01 to 20 MeV.NOTE 1—Since electrons with energies less than 0.01 MeV may not penetrate the container of the solution, the solutions may be stirred in an open beaker with the electrons entering the solutions directly (1).1.2.5 The irradiation temperature range is from −40 to +60°C.1.3 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.

定价： 0元 / 折扣价： 0 元

The alanine-EPR dosimetry system provides a means for measuring absorbed dose. It is based on the measurement of specific stable free radicals in crystalline alanine generated by ionizing radiation.Alanine-EPR dosimetry systems are used in reference- or transfer-standard or routine dosimetry systems in radiation applications that include: sterilization of medical devices and pharmaceuticals, food irradiation, polymer modifications, medical therapy and radiation damage studies in materials (1, 13-15).1.1 This practice covers dosimeter materials, instrumentation, and procedures for using the alanine-EPR dosimetry system for measuring the absorbed dose in the photon and electron radiation processing of materials. The system is based on electron paramagnetic resonance (EPR) spectroscopy of free radicals derived from the amino acid alanine.1.2 The alanine dosimeter is classified as a type I dosimeter as it is affected by individual influence quantities in a well-defined way that can be expressed in terms of independent correction factors (see ASTM Practice E2628). The alanine dosimeter may be used in either a reference standard dosimetry system or in a routine dosimetry system.1.3 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 ASTM E2628 “Practice for Dosimetry in Radiation Processing” for alanine dosimetry system. It should be read in conjunction with ASTM E2628.1.4 This practice covers alanine-EPR dosimetry systems for dose measurements under the following conditions:1.4.1 The absorbed dose range is between 1 and 1.5 × 105Gy.1.4.2 The absorbed dose rate is up to 102Gy s-1 for continuous radiation fields and up to 3 × 1010Gy s-1 for pulsed radiation fields (1-4).1.4.3 The radiation energy for photons and electrons is between 0.1 and 30 MeV (1, 2, 5-8).1.4.4 The irradiation temperature is between –78 °C and + 70 °C (2, 9-12).1.5 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.

定价： 487元 / 折扣价： 414 元 加购物车

4.1 A variety of products and materials are irradiated with X-radiation to modify their characteristics and improve the economic value or to reduce their microbial population for health-related purposes. Dosimetry requirements might vary depending on the type and end use of the product. Some examples of irradiation applications where dosimetry may be used are:4.1.1 Sterilization of health care products;4.1.2 Treatment of food for the purpose of parasite and pathogen control, insect disinfestation, and shelf life extension;4.1.3 Disinfection of consumer products;4.1.4 Cross-linking or degradation of polymers and elastomers;4.1.5 Curing composite material;4.1.6 Polymerization of monomers and oligomer and grafting of monomers onto polymers;4.1.7 Enhancement of color in gemstones and other materials;4.1.8 Modification of characteristics of semiconductor devices; and4.1.9 Research on materials effects of irradiation.NOTE 3: Dosimetry with measurement traceability and with known measurement uncertainty is required for regulated irradiation processes, such as the sterilization of health care products and treatment of food. Dosimetry may be less important for other industrial processes, such as polymer modification, which can be evaluated by changes in the physical properties of the irradiated materials. Nevertheless, routine dosimetry may be used to monitor the reproducibility of the radiation process.4.2 Radiation processing specifications usually include a pair of absorbed-dose limits: a minimum value to ensure the intended beneficial effect and a maximum value that the product can tolerate while still meeting its functional or regulatory specifications. For a given application, one or both of these values may be prescribed by process specifications or regulations. Knowledge of the dose distribution within irradiated material is essential to help meet these requirements. Dosimetry is essential to the radiation process since it is used to determine both of these limits and to confirm that the product is routinely irradiated within these limits.4.3 Several critical parameters must be controlled to obtain reproducible dose distributions in the process load. The absorbed-dose distribution within the product depends on the overall product dimensions and mass and irradiation geometry. The processing rate and dose distribution depend on the X-ray intensity, photon energy spectrum, and spatial distribution of the radiation field and conveyor speed.4.4 Before an irradiator can be used, it must be qualified (IQ, OQ) to determine its effectiveness in reproducibly delivering known, controllable absorbed doses. This involves testing the process equipment, calibrating the equipment and dosimetry system, and characterizing the magnitude, distribution and reproducibility of the absorbed dose delivered by the irradiator for a range of product densities.4.5 To ensure consistent dose delivery in a qualified irradiation process, routine process control requires procedures for routine product dosimetry and for product handling before and after the treatment, consistent product loading configuration, control and monitoring of critical process parameters, and documentation of the required activities and functions.1.1 This practice outlines the dosimetric procedures to be followed during installation qualification, operational qualification, performance qualification and routine processing at an X-ray (bremsstrahlung) irradiator. Other procedures related to operational qualification, performance qualification and routine processing that may influence absorbed dose in the product are also discussed.NOTE 1: Dosimetry is only one component of a total quality assurance program for adherence to good manufacturing practices used in radiation processing applications.NOTE 2: ISO/ASTM Practices 51649, 51818 and 51702 describe dosimetric procedures for electron beam and gamma facilities for radiation processing.1.2 For radiation sterilization of health care products, see ISO 11137-1, Sterilization of health care products – Radiation – Part 1: Requirements for development, validation and routine control of a sterilization process for medical devices. In those areas covered by ISO 11137-1, that standard takes precedence.1.3 For irradiation of food, see ISO 14470, Food irradiation – Requirements for development, validation and routine control of the process of irradiation using ionizing radiation for the treatment of food. In those areas covered by ISO 14470, that standard takes precedence.1.4 This document is one of a set of standards that provides recommendations for properly implementing and utilizing dosimetry in radiation processing. It is intended to be read in conjunction with ISO/ASTM Practice 52628, “Practice for Dosimetry in Radiation Processing”.1.5 In contrast to monoenergetic gamma radiation, the X-ray energy spectrum extends from low values (about 35 keV) up to the maximum energy of the electrons incident on the X-ray target (see Section 5 and Annex A1).1.6 Information about effective or regulatory dose limits and energy limits for X-ray applications is not within the scope of this practice.1.7 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.

定价： 777元 / 折扣价： 661 元 加购物车

4.1 This practice is applicable to the use of calorimetric dosimetry systems for the measurement of absorbed dose in electron beams, the qualification of electron irradiation facilities, periodic checks of operating parameters of electron irradiation facilities, and calibration of other dosimetry systems in electron beams. Calorimetric dosimetry systems are most suitable for dose measurement at electron irradiation facilities utilizing conveyor systems for transport of product during irradiation.NOTE 1: For additional information on calorimetric dosimetry system operation and use, see ICRU Report 80. For additional information on the use of dosimetry in electron accelerator facilities, see ISO/ASTM 51649, and ICRU Reports 34 and 35, and Refs (1-3).64.2 The calorimetric dosimetry systems described in this practice are not primary standard dosimetry systems. The calorimeters are classified as Type II dosimeters (ISO/ASTM 52628). They might be used as internal standards at an electron beam irradiation facility, including being used as transfer standard dosimetry systems for calibration of other dosimetry systems, or they might be used as routine dosimeters. The calorimetric dosimetry systems are calibrated by comparison with transfer standard dosimeters.4.3 The dose measurement is based on the measurement of the temperature rise (dosimeter response) in an absorber (calorimetric body) irradiated by an electron beam. Different absorbing materials are used, but the response is usually defined in terms of dose to water.NOTE 2: The calorimetric bodies of the calorimeters described in this practice are made from low atomic number materials. The electron fluences within these calorimetric bodies are almost independent of energy when irradiated with electron beams of 1.5 MeV or higher, and the mass collision stopping powers are approximately the same for these materials.4.4 The absorbed dose in other materials irradiated under equivalent conditions can be calculated. Procedures for making such calculations are given in ASTM Practices E666 and E668, and Ref (1).4.4.1 Calorimeters for use at industrial electron accelerators have been constructed using graphite, polystyrene or a Petri dish filled with water as the calorimetric body (4-10). The thickness of the calorimetric body should be less than the range of the incident electrons.4.4.2 Polymeric materials other than polystyrene might also be used for calorimetric measurements. Polystyrene is used because it is known to be resistant to radiation (11) and because almost no exo- or endothermic reactions take place (12).1.1 This practice covers the preparation and use of semi-adiabatic calorimetric dosimetry systems for measurement of absorbed dose and for calibration of routine dosimetry systems when irradiated with electrons for radiation processing applications. The calorimeters are either transported by a conveyor past a scanned electron beam or are stationary in a broadened beam.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 a calorimetric dosimetry system. It is intended to be read in conjunction with ISO/ASTM Practice 52628.1.3 The calorimeters described in this practice are classified as Type II dosimeters on the basis of the complex effect of influence quantities. See ISO/ASTM Practice 52628.1.4 This practice applies to electron beams in the energy range from 1.5 to 12 MeV.1.5 The absorbed dose range depends on the calorimetric absorbing material and the irradiation and measurement conditions. Minimum dose is approximately 100 Gy and maximum dose is approximately 50 kGy.1.6 The average absorbed-dose rate range shall generally be greater than 10 Gy·s-1.1.7 The temperature range for use of these calorimetric dosimetry systems depends on the thermal resistance of the calorimetric materials, on the calibration range of the temperature sensor, and on the sensitivity of the measurement device.1.8 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.1.9 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.

定价： 468元 / 折扣价： 398 元 加购物车

4.1 Various products and materials are routinely irradiated at pre-determined doses at electron beam facilities to preserve or modify their characteristics. Dosimetry requirements may vary depending on the radiation process and end use of the product. A partial list of processes where dosimetry may be used is given below.4.1.1 Polymerization of monomers and grafting of monomers onto polymers,4.1.2 Cross-linking or degradation of polymers,4.1.3 Curing of composite materials,4.1.4 Sterilization of health care products,4.1.5 Disinfection of consumer products,4.1.6 Food irradiation (parasite and pathogen control, insect disinfestation, and shelf-life extension),4.1.7 Control of pathogens and toxins in drinking water,4.1.8 Control of pathogens and toxins in liquid or solid waste,4.1.9 Modification of characteristics of semiconductor devices,4.1.10 Color enhancement of gemstones and other materials, and4.1.11 Research on radiation effects on materials.4.2 Dosimetry is used as a means of monitoring the irradiation process.NOTE 2: Dosimetry with measurement traceability and known uncertainty is required for regulated radiation processes such as sterilization of health care products (see ISO 11137-1 and Refs (1-36)) and preservation of food (see ISO 14470 and Ref (4)). It may be less important for other processes, such as polymer modification, which may be evaluated by changes in the physical and chemical properties of the irradiated materials. Nevertheless, routine dosimetry may be used to monitor the reproducibility of the treatment process.NOTE 3: Measured dose is often characterized as absorbed dose in water. Materials commonly found in single-use disposable medical devices and food are approximately equivalent to water in the absorption of ionizing radiation. Absorbed dose in materials other than water may be determined by applying conversion factors (5, 6).4.3 An irradiation process usually requires a minimum absorbed dose to achieve the desired effect. There may also be a maximum dose limit that the product can tolerate while still meeting its functional or regulatory specifications. Dosimetry is essential, since it is used to determine both of these limits during the research and development phase, and also to confirm that the product is routinely irradiated within these limits.4.4 The dose distribution within the product depends on process load characteristics, irradiation conditions, and operating parameters.4.5 Dosimetry systems must be calibrated with traceability to national or international standards and the measurement uncertainty must be known.4.6 Before a radiation facility is used, it must be characterized to determine its effectiveness in reproducibly delivering known, controllable doses. This involves testing and calibrating the process equipment, and dosimetry system.4.7 Before a radiation process is commenced it must be validated. This involves execution of Installation Qualification (IQ), Operational Qualification (OQ), and Performance Qualification (PQ), based on which process parameters are established that will ensure that product is irradiated within specified limits.4.8 To ensure consistent and reproducible dose delivery in a validated process, routine process control requires that documented procedures are established for activities to be carried out before, during and after irradiation, such as for ensuring consistent product loading configuration and for monitoring of critical operating parameters and routine dosimetry.1.1 This practice outlines dosimetric procedures to be followed in installation qualification (IQ), operational qualification (OQ) and performance qualifications (PQ), and routine processing at electron beam facilities.1.2 The electron beam energy range covered in this practice is between 300 keV and 25 MeV, although there are some discussions for other energies.1.3 Dosimetry is only one component of a total quality assurance program for adherence to good manufacturing practices used in radiation processing applications. Other measures besides dosimetry may be required for specific applications such as health care product sterilization and food preservation.1.4 Specific standards exist for the radiation sterilization of health care products and the irradiation of food. For the radiation sterilization of health care products, see ISO 11137-1 (Requirements) and ISO 11137-3 (Guidance on dosimetric aspects). For irradiation of food, see ISO 14470. In those areas covered by these standards, they take precedence. Information about effective or regulatory dose limits for food products is not within the scope of this practice (see ASTM Guides F1355, F1356, F1736, and F1885).1.5 This document is one of a set of standards that provides recommendations for properly implementing and utilizing dosimetry in radiation processing. It is intended to be read in conjunction with ISO/ASTM 52628, “Practice for Dosimetry in Radiation Processing”.NOTE 1: For guidance in the calibration of routine dosimetry systems, see ISO/ASTM Practice 51261. For further guidance in the use of specific dosimetry systems, see relevant ISO/ASTM Practices. For discussion of radiation dosimetry for pulsed radiation, see ICRU Report 34.1.6 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 requirements prior to use.

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The CTA dosimetry system provides a means for measuring absorbed dose based on a change in optical absorbance in the CTA dosimeter following exposure to ionizing radiation (5, 7-14).CTA dosimetry systems are commonly used in industrial radiation processing, for example in the modification of polymers and sterilization of health care products.CTA dosimeter film is particularly useful in absorbed dose mapping because it is available in a strip format and if measured using a strip measurement device, it can provide a dose map with higher resolution than using discrete points.1.1 This is a practice for using a cellulose triacetate (CTA) dosimetry system to measure absorbed dose in materials irradiated by photons or electrons in terms of absorbed dose to water. The CTA dosimetry system is classified as a routine dosimetry system.1.2 The CTA dosimeter is classified as a type II dosimeter on the basis of the complex effect of influence quantities on its response (see ASTM Practice E2628).1.3 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 ASTM E2628 “Practice for Dosimetry in Radiation Processing” for a CTA dosimetry system. It is intended to be read in conjunction with ASTM E2628.1.4 This practice covers the use of CTA dosimetry systems under the following conditions:1.4.1 The absorbed dose range is 10 kGy to 300 kGy.1.4.2 The absorbed-dose rate range is 3 Gy/s to 4×1010 Gy/s (1).1.4.3 The photon energy range is 0.1 to 50 MeV.1.4.4 The electron energy range is 0.2 to 50 MeV.1.5 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.

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4.1 Various products and materials routinely are irradiated at predetermined doses in gamma irradiation facilities to reduce their microbial population or to modify their characteristics. Dosimetry requirements may vary depending upon the irradiation application and end use of the product. Some examples of irradiation applications where dosimetry may be used are:4.1.1 Sterilization of medical devices,4.1.2 Treatment of food for the purpose of parasite and pathogen control, insect disinfestation, and shelf life extension,4.1.3 Disinfection of consumer products,4.1.4 Cross-linking or degradation of polymers and elastomers,4.1.5 Polymerization of monomers and grafting of monomers onto polymers,4.1.6 Enhancement of color in gemstones and other materials,4.1.7 Modification of characteristics of semiconductor devices, and4.1.8 Research on materials effects.NOTE 3: Dosimetry is required for regulated irradiation processes such as sterilization of medical devices and the treatment of food. It may be less important for other industrial processes, for example, polymer modification, which can be evaluated by changes in the physical and chemical properties of the irradiated materials.4.2 An irradiation process usually requires a minimum absorbed dose to achieve the intended effect. There also may be a maximum absorbed dose that the product can tolerate and still meet its functional or regulatory specifications. Dosimetry is essential to the irradiation process since it is used to determine both of these limits and to confirm that the product is routinely irradiated within these limits.4.3 The absorbed-dose distribution within the product depends on the overall product dimensions and mass, irradiation geometry, and source activity distribution.4.4 Before an irradiation facility can be used, it must be qualified to determine its effectiveness in reproducibly delivering known, controllable absorbed doses. This involves testing the process equipment, calibrating the equipment and dosimetry system, and characterizing the magnitude, distribution and reproducibility of the absorbed dose delivered by the irradiator for a range of product densities.4.5 To ensure consistent and reproducible dose delivery in a qualified process, routine process control requires documented product handling procedures before and after irradiation, consistent product loading configuration, control and monitoring of critical process parameters, routine product dosimetry and documentation of the required activities.1.1 This practice outlines the installation qualification program for an irradiator and the dosimetric procedures to be followed during operational qualification, performance qualification, and routine processing in facilities that process products with ionizing radiation from radionuclide gamma sources to ensure that product has been treated within a predetermined range of absorbed dose. Other procedures related to operational qualification, performance qualification, and routine processing that may influence absorbed dose in the product are also discussed.NOTE 1: Dosimetry is only one component of a total quality assurance program for adherence to good manufacturing practices used in radiation processing applications.NOTE 2: ISO/ASTM Practices 51818 and 51649 describe dosimetric procedures for low and high enery electron beam facilities for radiation processing and ISO/ASTM Practice 51608 describes procedures for X-ray (bremsstrahlung) facilities for radiation processing.1.2 For the radiation sterilization of health care products, see ISO 11137-1. In those areas covered by ISO 11137-1, that standard takes precedence.1.3 This document is one of a set of standards that provides recommendations for properly implementing and utilizing dosimetry in radiation processing. It is intended to be read in conjunction with ASTM Practice E2628.1.4 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.1.5 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.

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4.1 All measurements, including dose measurements, have an associated uncertainty. The magnitude of the measurement uncertainty is important for assessing the quality of the results of the measurement system.4.2 Information on the range of achievable uncertainty values for specific dosimetry systems is given in the ISO/ASTM standards for the specific dosimetry systems. While the uncertainty values given in specific dosimetry standards are achievable, it should be noted that both smaller and larger uncertainty values might be obtained depending on measurement conditions and instrumentation. For more information see also ISO/ASTM 52628.4.3 This guide uses the methodology adopted by the GUM for estimating uncertainties in measurements (see 2.4). Therefore, components of uncertainty are evaluated as either Type A uncertainty or Type B uncertainty.4.4 Quantifying individual components of uncertainty may assist the user in identifying actions to reduce the measurement uncertainty.4.5 Periodically, the uncertainty should be reassessed to confirm the existing estimate. Should changes occur that could influence the existing component estimates or result in the addition of new components of uncertainty, a new estimate of uncertainty should be established.4.6 Although this guide provides a framework for assessing uncertainty, it cannot substitute for critical thinking, intellectual honesty, and professional skill. The evaluation of uncertainty is neither a routine task nor a purely mathematical one; it depends on detailed knowledge of the nature of the measurand and of the measurement method and procedure used. The quality and utility of the uncertainty quoted for the result of a measurement therefore ultimately depends on the understanding, critical analysis, and integrity of those who contribute to the assignment of its value (JCGM 100:2008).1.1 This standard provides guidance on the use of concepts described in the JCGM Evaluation of Measurement Data – Guide to the Expression of Uncertainty in Measurement (GUM) to estimate the uncertainties in the measurement of absorbed dose in radiation processing.1.2 Methods are given for identifying, evaluating and estimating the components of measurement uncertainty associated with the use of dosimetry systems and for calculating combined standard measurement uncertainty and expanded (overall) uncertainty of dose measurements based on the GUM methodology.1.3 Examples are given on how to develop a measurement uncertainty budget and a statement of uncertainty.1.4 This document is one of a set of standards that provides recommendations for properly implementing dosimetry in radiation processing, and provides guidance for achieving compliance with the requirements of ISO/ASTM 52628 related to the evaluation and documentation of the uncertainties associated with measurements made with a dosimetry system. It is intended to be read in conjunction with ISO/ASTM 52628, ISO/ASTM 51261 and ISO/ASTM 52701.1.5 This guide does not address the establishment of process specifications or conformity assessment.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.

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4.1 Food products may be treated with ionizing radiation, such as gamma-rays from 60Co or 137Cs sources, for numerous purposes, including control of parasites and pathogenic microorganisms, insect disinfestation, growth and maturation inhibition, and shelf-life extension. Food irradiation specifications almost always include a minimum or maximum limit of absorbed dose, sometimes both: a minimum limit is set to ensure that the intended beneficial effect is achieved and a maximum limit is set for the purpose of avoiding product or packaging degradation. For a given application, one or both of these values may be prescribed by government regulations that have been established on the basis of scientific data. Therefore, prior to the irradiation of the food product, it is necessary to determine the capability of an irradiation facility to deliver the absorbed dose within any prescribed limits. Also, it is necessary to monitor and document the absorbed dose during each production run to verify compliance with the process specifications at a predetermined level of confidence.NOTE 3 - The Codex Alimentarius Commission has developed an international General Standard and a Code of Practice that address the application of ionizing radiation to the treatment of foods and that strongly emphasize the role of dosimetry for ensuring that irradiation will be properly performed (1).4.2 Some food products are processed in the chilled or frozen state. Therefore, dosimeters used for routine processing should be selected for their functionality under those conditions. Moreover, the temperature of a dosimeter during irradiation should be sufficiently stable to allow correction for temperature effects on the dosimeter response. To avoid the influence of temperature gradients on dosimeter response and the subsequent need to correct for these effects, methods that isolate the dosimeter from temperature gradients may be employed.NOTE 4 - For more detailed discussions of radiation processing of various foods, see ASTM Guides F 1355, F 1356, F 1736, and F 1885 and Refs (1-11).4.3 To ensure that products are irradiated within a specified absorbed-dose range, routine process control requires routine product dosimetry, documented product handling procedures (before, during, and after irradiation), consistent orientation of the products during irradiation, monitoring of critical process parameters, and documentation of all relevant activities and functions.1.1 This practice outlines the installation qualification program for an irradiator and the dosimetric procedures to be followed during operational qualification, performance qualification, and routine processing in facilities that process food with ionizing radiation from radionuclide gamma sources to ensure that product has been treated within a predetermined range of absorbed dose. Other procedures related to operational qualification, performance qualification, and routine processing that may influence absorbed dose in the product are also discussed. Information about effective or regulatory dose limits for food products is not within the scope of this practice (see ASTM Guides F 1355, F 1356, F 1736, and F 1885).Note 1—Dosimetry is only one component of a total quality assurance program for adherence to good manufacturing practices used in the production of safe and wholesome food.Note 2—ISO/ASTM Practice 51431 describes dosimetric procedures for electron beam and X-ray (bremsstrahlung) irradiation facilities for food processing.1.2 For guidance in the selection and calibration of dosimetry systems, and interpretation of measured absorbed dose in the product, see ISO/ASTM Guide 51261 and ASTM Practice E 666. For the use of specific dosimetry systems, see ASTM Practices E 1026 and E 2304, and ISO/ASTM Practices 51205, 51275, 51276, 51310, 51401, 51538, 51540, 51607, 51650, and 51956. For discussion of radiation dosimetry for gamma-rays and X-rays also see ICRU Report 14.1.3 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.

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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.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 × 102 to 5 × 104 Gy (1).21.5.2 The absorbed-dose rate does not exceed 106 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.

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4.1 Ionizing radiation is used to produce various desired effects in products. Examples of applications include the sterilization of medical products, microbial reduction, modification of polymers and electronic devices, and curing of inks, coatings, and adhesives (4).4.2 Absorbed-dose measurements, with statistical controls and documentation, are necessary to ensure that products receive the desired absorbed dose. These controls include a program that addresses requirements for calibration of routine dosimetry system.4.3 A routine dosimetry system calibration procedure as described in this document provides the user with a dosimetry system whose dose measurements are traceable to national or international standards for the conditions of use (see Annex A4). The dosimetry system calibration is part of the user’s measurement management system.1.1 This practice specifies the requirements for calibrating routine dosimetry systems for use in radiation processing, including establishing measurement traceability and estimating uncertainty in the measured dose using the calibrated dosimetry system.NOTE 1: Regulations or other directives exist in many countries that govern certain radiation processing applications such as sterilization of healthcare products and radiation processing of food requiring that absorbed-dose measurements be traceable to national or international standards (ISO 11137-1, Refs (1-3)2).1.2 The absorbed-dose range covered is up to 1 MGy.1.3 The radiation types covered are photons and electrons with energies from 80 keV to 25 MeV.1.4 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 ASTM E2628 “Practice for Dosimetry in Radiation Processing” for the calibration of routine dosimetry systems. It is intended to be read in conjunction with ASTM E2628 and the relevant ASTM or ISO/ASTM standard practice for the dosimetry system being calibrated referenced in Section 2.1.5 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.1.6 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.

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