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    ASTM E2861 - 16(2020)

    Standard Test Method for Measurement of Beam Divergence and Alignment in Neutron Radiologic Beams

    Active Standard ASTM E2861 | Developed by Subcommittee: E07.05

    Book of Standards Volume: 03.04

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    Significance and Use

    5.1 As discussed in Practice E748, traditional neutron radiography typically employs a high flux reactor source with a well defined collimation system to produce an image on film. The alignment of the imaging plane and the divergence angle are generally well defined and a small degree of misalignment or uncertainty in divergence angle makes little difference in the final image. These systems are well characterized by their physical dimension, the L/D ratio, and image quality indicators (Beam Purity Indicator and Sensitivity Indicator) described in Test Method E545. Neutron computed tomography is an example where it is important to know with some precision both the beam’s centerline and the degree of beam divergence, especially if the beam does not closely approximate a parallel beam. Portable or movable neutron imaging systems often utilize shorter collimation systems, a less precise alignment and poor symmetry in divergence angles, which may affect image analysis. In these example cases, direct measurement of the alignment and the divergence angles is desirable as calculation from system geometry would be less straightforward and accurate. Fabrication of the device is an extension of the Test Method E803 L/D device, providing different information through a similar approach.

    1. Scope

    1.1 This test method covers the design, materials, manufacture, and use of a divergence and alignment indicator (DAI) for measuring the effective divergence of a thermal neutron beam used for neutron imaging as well as determining the alignment of the imaging plane relative (usually normal) to the centerline of the beam. This test method is applicable to thermal neutron imaging.

    1.2 The values stated in SI units are to be regarded as the standard.

    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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

    1.4 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.

    Other Documents

    ANSI Y14.5M Dimensioning and Tolerances

    ASTM Standards

    E543 Specification for Agencies Performing Nondestructive Testing

    E545 Test Method for Determining Image Quality in Direct Thermal Neutron Radiographic Examination

    E748 Guide for Thermal Neutron Radiography of Materials

    E803 Test Method for Determining the L/DRatio of Neutron Radiography Beams

    E1316 Terminology for Nondestructive Examinations

    ICS Code

    ICS Number Code 19.100 (Non-destructive testing)

    UNSPSC Code

    UNSPSC Code 41111800(Non destructive examination equipment)

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

    DOI: 10.1520/E2861-16R20

    Citation Format

    ASTM E2861-16(2020), Standard Test Method for Measurement of Beam Divergence and Alignment in Neutron Radiologic Beams, ASTM International, West Conshohocken, PA, 2020, www.astm.org

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