ASTM E1931-09

Standard Guide for X-Ray Compton Scatter Tomography

SIGNIFICANCE AND USE
Principal Advantage of Compton Scatter Tomography—The principal advantage of CST is the ability to perform three-dimensional X-ray examination without the requirement for access to the back side of the examination object. CST offers the possibility to perform X-ray examination that is not possible by any other method. The CST sub-surface slice image is minimally affected by examination object features outside the plane of examination. The result is a radioscopic image that contains information primarily from the slice plane. Scattered radiation limits image quality in normal radiographic and radioscopic imaging. Scatter radiation does not have the same detrimental effect upon CST because scatter radiation is used to form the image. In fact, the more radiation the examination object scatters, the better the CST result. Low subject contrast materials that cannot be imaged well by conventional radiographic and radioscopic means are often excellent candidates for CST. Very high contrast sensitivities and excellent spatial resolution are possible with CST tomography.
Limitations—As with any nondestructive testing method, CST has its limitations. The technique is useful on reasonably thick sections of low-density materials. While a 25 mm (1 in.) depth in aluminum or 50 mm (2 in.) in plastic is achievable, the examination depth is decreased dramatically as the material density increases. Proper image interpretation requires the use of standards and examination objects with known internal conditions or representative quality indicators (RQIs). The examination volume is typically small, on the order of a few cubic inches and may require a few minutes to image. Therefore, completely examining large structures with CST requires intensive re-positioning of the examination volume that can be time-consuming. As with other penetrating radiation methods, the radiation hazard must be properly addressed.
SCOPE
1.1 Purpose—This guide covers a tutorial introduction to familiarize the reader with the operational capabilities and limitations inherent in X-ray Compton Scatter Tomography (CST). Also included is a brief description of the physics and typical hardware configuration for CST.
1.2 Advantages—X-ray Compton Scatter Tomography (CST) is a radiologic nondestructive examination method with several advantages that include:
1.2.1 The ability to perform X-ray examination without access to the opposite side of the examination object;
1.2.2 The X-ray beam need not completely penetrate the examination object allowing thick objects to be partially examined. Thick examination objects become part of the radiation shielding thereby reducing the radiation hazard;
1.2.3 The ability to examine and image object subsurface features with minimal influence from surface features;
1.2.4 The ability to obtain high-contrast images from low subject contrast materials that normally produce low-contrast images when using traditional transmitted beam X-ray imaging methods; and  
1.2.5 The ability to obtain depth information of object features thereby providing a three-dimensional examination. The ability to obtain depth information presupposes the use of a highly collimated detector system having a narrow angle of acceptance.
1.3 Applications—This guide does not specify which examination objects are suitable, or unsuitable, for CST. As with most nondestructive examination techniques, CST is highly application specific thereby requiring the suitability of the method to be first demonstrated in the application laboratory. This guide does not provide guidance in the standardized practice or application of CST techniques. No guidance is provided concerning the acceptance or rejection of examination objects examined with CST.
1.4 Limitations—As with all nondestructive examination methods, CST has limitations and is complementary to other NDE methods. Chief among the limitations is the difficulty in performing CST on thick...

General Information

• Status: Historical
• Publication Date: 31-May-2009
• ICS: 35.240.80 - IT applications in health care technology
• Technical Committee: E07 - Nondestructive Testing
• Drafting Committee: E07.01 - Radiology (X and Gamma) Method

Relations

• Replaces: ASTM E1931-97(2003) - Standard Guide for X-Ray Compton Scatter Tomography
• Effective Date: 01-Jun-2009

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: E1931 − 09
StandardGuide for
1
X-Ray Compton Scatter Tomography
This standard is issued under the fixed designation E1931; 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 NDE methods. Chief among the limitations is the difficulty in
performing CST on thick sections of high-Z materials. CST is
1.1 Purpose—This guide covers a tutorial introduction to
best applied to thinner sections of lower Z materials. The
familiarize the reader with the operational capabilities and
following provides a general idea of the range of CST
limitations inherent in X-ray Compton Scatter Tomography
applicability when using a 160 keV constant potential X-ray
(CST). Also included is a brief description of the physics and
source:
typical hardware configuration for CST.
Material Practical Thickness Range
1.2 Advantages—X-ray Compton Scatter Tomography
1
(CST) is a radiologic nondestructive examination method with Steel Up to about 3 mm ( ⁄8 in.)
Aluminum Up to about 25 mm (1 in.)
several advantages that include:
Aerospace composites Up to about 50 mm (2 in.)
1.2.1 The ability to perform X-ray examination without
Polyurethane Foam Up to about 300 mm (12 in.)
access to the opposite side of the examination object;
The limitations of the technique must also consider the
1.2.2 The X-ray beam need not completely penetrate the
required X, Y, and Z axis resolutions, the speed of image
examination object allowing thick objects to be partially
formation, image quality and the difference in the X-ray
examined. Thick examination objects become part of the
scattering characteristics of the parent material and the internal
radiation shielding thereby reducing the radiation hazard;
features that are to be imaged.
1.2.3 The ability to examine and image object subsurface
1.5 The values stated in both inch-pound and SI units are to
features with minimal influence from surface features;
be regarded separately as the standard. The values given in
1.2.4 The ability to obtain high-contrast images from low
parentheses are for information only.
subject contrast materials that normally produce low-contrast
1.6 This standard does not purport to address all of the
imageswhenusingtraditionaltransmittedbeamX-rayimaging
safety concerns, if any, associated with its use. It is the
methods; and
responsibility of the user of this standard to establish appro-
1.2.5 The ability to obtain depth information of object
features thereby providing a three-dimensional examination. priate safety and health practices and to determine the
applicability of regulatory limitations prior to use.
The ability to obtain depth information presupposes the use of
a highly collimated detector system having a narrow angle of
2. Referenced Documents
acceptance.
2
2.1 ASTM Standards:
1.3 Applications—Thisguidedoesnotspecifywhichexami-
E747 Practice for Design, Manufacture and Material Group-
nation objects are suitable, or unsuitable, for CST. As with
ing Classification of Wire Image Quality Indicators (IQI)
most nondestructive examination techniques, CST is highly
Used for Radiology
application specific thereby requiring the suitability of the
E1025 Practice for Design, Manufacture, and Material
method to be first demonstrated in the application laboratory.
Grouping Classification of Hole-Type Image Quality In-
This guide does not provide guidance in the standardized
dicators (IQI) Used for Radiology
practice or application of CST techniques. No guidance is
E1255 Practice for Radioscopy
provided concerning the acceptance or rejection of examina-
E1316 Terminology for Nondestructive Examinations
tion objects examined with CST.
E1441 Guide for Computed Tomography (CT) Imaging
1.4 Limitations—As with all nondestructive examination
E1453 Guide for Storage of Magnetic Tape Media that
methods, CST has limitations and is complementary to other
Contains Analog or Digital Radioscopic Data
1
This guide is under the jurisdiction of ASTM Committee E07 on Nondestruc-
tiveTesting and is the direct responsibility of E07.01 on Radiology (X and Gamma)
2
Method. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
CurrenteditionapprovedJune1,2009.PublishedJuly2009.Originallyapproved contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
in 1997. Last previous edition approved in 2003 as E1931 - 97(2003). DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/E1931-09. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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This document is not anASTM standard and is intended only to provide the user of anASTM 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:E1931–97 (Reapproved 2003) Designation:E1931–09
Standard Guide for
1
X-Ray Compton Scatter Tomography
This standard is issued under the fixed designation E 1931; 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 Purpose—This guide covers a tutorial introduction to familiarize the reader with the operational capabilities and limitations
inherent in X-ray Compton Scatter Tomography (CST). Also included is a brief description of the physics and typical hardware
configuration for CST.
1.2 Advantages—X-ray Compton Scatter Tomography (CST) is a radiologic nondestructive examination method with several
advantages that include:
1.2.1 The ability to perform X-ray examination without access to the opposite side of the examination object;
1.2.2 The X-ray beam need not completely penetrate the examination object allowing thick objects to be partially examined.
Thick examination objects become part of the radiation shielding thereby reducing the radiation hazard;
1.2.3 The ability to image examinationexamine and image object subsurface features with minimal influence from surface
features;
1.2.4 The ability to obtain high-contrast images from low subject contrast materials that normally produce low-contrast images
when using traditional transmitted beam X-ray imaging methods; and
1.2.5 The ability to obtain depth information for examination of object features thereby providing a three-dimensional
examination. The ability to obtain depth information presupposes the use of a highly collimated detector system having a narrow
angle of acceptance.
1.3 Applications— This guide does not specify which examination objects are suitable, or unsuitable, for CST. As with most
nondestructiveexaminationtechniques,CSTishighlyapplicationspecifictherebyrequiringthesuitabilityofthemethodtobefirst
demonstratedintheapplicationlaboratory.ThisguidedoesnotprovideguidanceinthestandardizedpracticeorapplicationofCST
techniques. No guidance is provided concerning the acceptance or rejection of examination objects examined with CST.
1.4 Limitations— As with all nondestructive examination methods, CST has limitations and is complementary to other NDE
methods. Chief among the limitations is the difficulty in performing CSTon thick sections of high-Z materials. CSTis best applied
to thinner sections of lower Z materials.The following provides a general idea of the range of CSTapplicability when using a 160
keV constant potential X-ray source:
Material Practical Thickness Range
1
Steel Up to about 3 mm [ ⁄8 in.]
1
Steel Up to about 3 mm ( ⁄8 in.)
Aluminum Up to about 25 mm [1 in.]
Aluminum Up to about 25 mm (1 in.)
Aerospace composites Up to about 50 mm [2 in.]Up to about
50 mm (2 in.)
Aerospace composites Up to about 50 mm (2 in.)
Polyurethane Foam Up to about 300 mm (12 in.)
ThelimitationsofthetechniquemustalsoconsidertherequiredX,Y,andZaxisresolutions,thespeedofimageformation,image
quality and the difference in the X-ray scattering characteristics of the parent material and the internal features that are to be
imaged.
1.5 The values stated in both inch-pound and SI units are to be regarded separately as the standard. The values given in
parentheses are for information only.
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 to determine the applicability of regulatory
limitations prior to use.
1
This guide is under the jurisdiction of ASTM Committee E07 on Nondestructive Testing and is the direct responsibility of Subcommittee E07.01 on Radiology (X and
Gamma) Method.
Current edition approved March 10, 2003. Published May 2003. Originally approved in 1997. Last previous edition approved in 1997 as E1931–97.
Current edition approved June 1, 2009. Published July 2009. Originally approved in 1997. Last previous edition approved in 2003 as E 1931 - 97(2003).
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1

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E1931–09
2. Referenced Documents
2
2.1 ASTM Standards:
E 747 Practice for Design, Manufacture, and Material Grouping Classification ofWire Image Quality Indicator
...