ASTM E803-20
(Test Method)Standard Test Method for Determining the L/D Ratio of Neutron Radiography Beams
Standard Test Method for Determining the <emph type="ital">L/D </emph>Ratio of Neutron Radiography Beams
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.
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.
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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.
Designation:E803 −20
Standard Test Method for
1
Determining the L/DRatio of Neutron Radiography Beams
This standard is issued under the fixed designation E803; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* 2. Referenced Documents
2
2.1 ASTM Standards:
1.1 This test method defines an empirical technique for the
measurement of the effective collimation ratio, L/D, of neutron E748 Guide for Thermal Neutron Radiography of Materials
E1316 Terminology for Nondestructive Examinations
radiography beams. The technique is based upon analysis of a
neutron radiographic image and is independent of measure-
3. Summary of Test Method
ments and calculations based on physical dimensions of the
collimation system. The values derived by this technique 3.1 Determination of neutron beam L/D ratio (length of the
should be more accurate than those based on physical beam line divided by the diameter of the aperture) using the
3
measurements, particularly for poorly defined apertures. NU (no umbra) technique is accomplished by radiographing
the NU device with the neutron beam to be measured and
1.2 Thistestmethodcoversboththemanufactureanduseof
subsequently analyzing the resulting image by one of three
the device to measure L/D ratios.
methods. Each of the three methods is based upon the
1.3 Neutron images for this method can be produced on
determination of that point at which the umbral shadow width
radiographic film using an appropriate conversion screen as
reaches zero. See Fig. 1. The neutron radiography method is
detailed in Guide E748 or a CR screen with appropriate
discussed in Guide E748 and the terms are defined in Termi-
neutron converter. The method has not been validated with
nology E1316.
images produced by digital detector arrays.
4. Significance and Use
1.4 Thistestmethodonlyappliestoneutronbeamlineswith
cold or thermal neutron spectrums. 4.1 The quality of a neutron radiographic image is depen-
dent upon many factors. The L/D ratio is one of those factors
1.5 Units—The values stated in SI units are to be regarded
and constitutes a numerical definition of the geometry of the
as standard.
neutron beam. The L/D ratio required for a specific neutron
1.6 This standard does not purport to address all of the
radiographic examination is dependent upon the thickness of
safety concerns, if any, associated with its use. It is the
the specimen and the physical characteristics of the particular
responsibility of the user of this standard to establish appro-
element of interest. Use of this test method allows the
priate safety, health, and environmental practices and deter-
radiographer and the user to determine and periodically mea-
mine the applicability of regulatory limitations prior to use.
sure the effective collimation ratio.
1.7 This international standard was developed in accor-
5. Apparatus
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
5.1 The NU Device (see Fig. 2(a) and (b), and Fig. 3)
Development of International Standards, Guides and Recom-
employsneutronabsorbingrodspositionedatvariousdistances
mendations issued by the World Trade Organization Technical
from the image plane. In practice, this device consists of
Barriers to Trade (TBT) Committee.
cadmium rods located inV-grooves accurately machined in the
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
1
This test method is under the jurisdiction of ASTM Committee E07 on contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Nondestructive Testing and is the direct responsibility of Subcommittee E07.05 on Standards volume information, refer to the standard’s Document Summary page on
Radiology (Neutron) Method. the ASTM website.
3
Current edition approved July 1, 2020. Published August 2020. Originally Newacheck, R. L., and Underhill, P. E., “The NU Method for Determining L/D
approved in 1986. Last previous edition approved in 2017 as E803 – 17. DOI: Ratio Of Neutron Radiography Facilities,” Aerotest Operations, Inc., Report A.O.
10.1520/E0803-20. 77-27, June 1977.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
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E803−20
FIG. 1 Diagram of Zero Umbra Image Configuration
NOTE 1—Rods at “A” posi
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E803 − 17 E803 − 20
Standard Test Method for
1
Determining the L/D Ratio of Neutron Radiography Beams
This standard is issued under the fixed designation E803; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
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
2
2.1 ASTM Standards:
E748 Guide for Thermal Neutron Radiography of Materials
E1316 Terminology for Nondestructive Examinations
3. Summary of Test Method
3.1 Determination of neutron beam L/D ratio (length of the beam line divided by the diameter of the aperture) using the NU (no
1
This test method is under the jurisdiction of ASTM Committee E07 on Nondestructive Testing and is the direct responsibility of Subcommittee E07.05 on Radiology
(Neutron) Method.
Current edition approved Nov. 1, 2017July 1, 2020. Published November 2017August 2020. Originally approved in 1986. Last previous edition approved in 20132017
as E803 – 91E803 – 17.(2013). DOI: 10.1520/E0803-17.10.1520/E0803-20.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
E803 − 20
3
umbra) technique is accomplished by radiographing the NU device with the neutron beam to be measured and subsequently
analyzing the resulting image by one of three methods. Each of the three methods is based upon the determination of that point
at which the umbral shadow width reaches zero. See Fig. 1. The neutron radiography method is discussed in Guide E748 and the
terms are defined in Terminology E1316.
4. 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.
5. Apparatus
5.1 The NU Device (see Fig. 2(a) and (b), and Fig. 3) employs neutron absorbing rods positioned at various distances from the
image plane. In practice, this device consists of cadmium rods located in V-grooves accurately machined in the surface of an
1
aluminum channel section
...
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