Significance and Use
4.1 Reliable dosimetry is indispensable for research on the effects of ionizing radiation on materials and products. Without reliable dosimetry valid conclusions cannot be reached, or the wrong conclusions might be reached.
4.2 This document is intended to provide direction on how to conduct dosimetry for research and experiments on the effects of ionizing radiation on materials and products, and on the reporting of dosimetry results. Requirements on dosimetry and on dose ranges might differ between the various types of experiments to be carried out.
4.3 Proper reporting of the manner in which the irradiation was carried out is important since the degree of radiation effect might be a function of various factors, other than absorbed dose, such as the radiation source, the absorbed-dose rate, energy of the incident radiation, ambient environmental conditions during irradiation, and the type of incident radiation. This document attempts to highlight the information, including the methodology and results of the absorbed-dose measurements, necessary for an experiment to be repeatable by other researchers.
4.4 In most cases an experiment should be designed to irradiate the sample as uniformly as possible. In practice, a certain variation in absorbed dose will exist throughout the sample. Absorbed-dose mapping is used to determine the magnitude, location, and reproducibility of the maximum (Dmax) and minimum absorbed dose (Dmin) for a given set of experimental parameters. Dosimeters used for dose mapping must be capable of operation over the expected range of doses and must have sufficient spatial resolution to determine likely dose gradients (see ISO/ASTM ).
4.5 Computer simulations might provide useful information about absorbed-dose distribution in the irradiated sample, especially near material interfaces (see ASTM ), but are not a substitute for dosimetry.
1.1 This document covers essential recommendations for dosimetry needed to conduct research on the effects of ionizing radiation on materials, products and biological samples. Such research includes establishment of the quantitative relationship between absorbed dose and the relevant effects. This document also describes the overall need for dosimetry in such research, and for reporting of the results. Dosimetry should be considered an integral part of the experiment, and the researcher is responsible for ensuring the accuracy and applicability of the dosimetry system used.
Note 1: For research involving food products, note that 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 which strongly emphasizes the role of dosimetry for ensuring that irradiation will be properly performed (. )
Note 2: This document includes tutorial information in the form of Notes. Researchers should also refer to the references provided at the end of the standard, and other applicable scientific literature, to assist in the experimental methodology as applied to dosimetry (. )
1.2 This document covers research conducted using the following types of ionizing radiation: gamma radiation (typically from Cobalt-60 or Cesium-137 sources), X-radiation (bremsstrahlung, typically with energies between 50 keV and 7.5 MeV), and electrons (typically with energies ranging from 80 keV to more than 10 MeV). See ISO/ASTM , , and .
1.3 This document describes dosimetry recommendations for establishing the experimental method. It does not include dosimetry recommendations for installation qualification or operational qualification of the irradiation facility. These subjects are treated in ISO/ASTM , , and .
1.4 This document is not intended to limit the flexibility of the researcher in the determination of the experimental methodology. The purpose of the document is to ensure that the radiation source and experimental methodology are chosen such that the results of the experiment will be useful and understandable to other scientists and regulatory agencies. The total uncertainty in the absorbed-dose measurement results and the absorbed-dose variation within the irradiated sample should be taken into account in the interpretation of the research results (see ISO/ASTM Guide ).
1.5 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 . This document is thus intended to be read in conjunction with ISO/ASTM .
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.