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    ASTM E803 - 20

    Standard Test Method for Determining the L/D Ratio of Neutron Radiography Beams

    Active Standard ASTM E803 | Developed by Subcommittee: E07.05

    Book of Standards Volume: 03.03

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    Significance and Use

    4.1 The quality of a neutron radiographic image is dependent upon many factors. The L/D ratio is one of those factors and constitutes a numerical definition of the geometry of the neutron beam. The L/D ratio required for a specific neutron radiographic examination is dependent upon the thickness of the specimen and the physical characteristics of the particular element of interest. Use of this test method allows the radiographer and the user to determine and periodically measure the effective collimation ratio.

    1. Scope

    1.1 This test method defines an empirical technique for the measurement of the effective collimation ratio, L/D, of neutron radiography beams. The technique is based upon analysis of a neutron radiographic image and is independent of measurements and calculations based on physical dimensions of the collimation system. The values derived by this technique should be more accurate than those based on physical measurements, particularly for poorly defined apertures.

    1.2 This test method covers both the manufacture and use of the device to measure L/D ratios.

    1.3 Neutron images for this method can be produced on radiographic film using an appropriate conversion screen as detailed in Guide E748 or a CR screen with appropriate neutron converter. The method has not been validated with images produced by digital detector arrays.

    1.4 This test method only applies to neutron beam lines with cold or thermal neutron spectrums.

    1.5 Units—The values stated in SI units are to be regarded as standard.

    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.

    2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

    ASTM Standards

    E748 Guide for Thermal Neutron Radiography of Materials

    E1316 Terminology for Nondestructive Examinations

    ICS Code

    ICS Number Code 19.100 (Non-destructive testing)

    Referencing This Standard
    Link Here
    Link to Active (This link will always route to the current Active version of the standard.)

    DOI: 10.1520/E0803-20

    Citation Format

    ASTM E803-20, Standard Test Method for Determining the L/D Ratio of Neutron Radiography Beams, ASTM International, West Conshohocken, PA, 2020, www.astm.org

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