ASTM E2809-13
(Guide)Standard Guide for Using Scanning Electron Microscopy/X-Ray Spectrometry in Forensic Paint Examinations
Standard Guide for Using Scanning Electron Microscopy/X-Ray Spectrometry in Forensic Paint Examinations
SIGNIFICANCE AND USE
4.1 The SEM can be used to define and compare the layer structure of multilayered samples, the structure of individual layers, the bulk elemental composition of individual layers, and the elemental composition of individual particulate components within paints and coatings.
4.2 The test methods described in this guide may have some limitations. They include the inability to detect elements in trace concentrations, the need for a conductive coating of the sample, the inability to remove a sample from most embedding materials after analysis, and the discoloration of materials by irradiation.
4.3 Although quantitative and semiquantitative methods are available for EDS (see Guide E1508), they are not appropriate for most paint analyses because of the typical heterogeneity of paint. Application of quantitative methods is further complicated by an inability to predict what compounds may be present (see 7.12.1).
4.4 The information available from a specimen may diminish as its size is reduced and its condition degrades. The smaller a specimen is, the less valuable it becomes for association with a known because it may contain fewer characteristics of the original material. As specimen size is reduced, it may no longer be representative of the original material. This may also be true of a degraded sample.
4.5 This guide is intended to advise and assist laboratory analysts in the effective application of scanning electron microscopy to the analysis of paint evidence. It is intended to be applicable to most modern scanning electron microscopes typically used in the forensic laboratory.
4.6 It is not the intention of this guide to present comprehensive methods of SEM. It is necessary that the analyst have an understanding of SEM operation and general concepts of specimen preparation before using this guide. This information is available from manufacturers’ reference materials, training courses, and references such as Scanning Electron Microscopy and X-ray Microa...
SCOPE
1.1 This guide is an outline of methods for scanning electron microscopy (SEM) intended for use by forensic paint examiners. This guide is intended to supplement information presented in Guide E1610.
1.2 The methods used by each examiner or laboratory or both depend upon sample size, sample suitability, and laboratory equipment.
1.3 The term “scanning electron microscopy” occasionally refers to the entire analytical system including energy dispersive X-ray spectrometry (EDS) or wavelength dispersive X-ray spectrometry (WDS) or both.
1.4 This guide does not cover the theoretical aspects of many of the topics presented.
1.5 This guide cannot replace knowledge, skill, or ability acquired through appropriate education, training, and experience and should be used in conjunction with sound professional judgment.
1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.7 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 determine the applicability of regulatory limitations prior to use.
General Information
Standards Content (Sample)
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Designation: E2809 − 13
Standard Guide for
Using Scanning Electron Microscopy/X-Ray Spectrometry in
1
Forensic Paint Examinations
This standard is issued under the fixed designation E2809; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber 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 guide is an outline of methods for scanning
E766Practice for Calibrating the Magnification of a Scan-
electron microscopy (SEM) intended for use by forensic paint
ning Electron Microscope
examiners. This guide is intended to supplement information
E1492Practice for Receiving, Documenting, Storing, and
presented in Guide E1610.
Retrieving Evidence in a Forensic Science Laboratory
1.2 The methods used by each examiner or laboratory or
E1508 Guide for Quantitative Analysis by Energy-
both depend upon sample size, sample suitability, and labora-
Dispersive Spectroscopy
tory equipment.
E1610Guide for Forensic Paint Analysis and Comparison
E1732Terminology Relating to Forensic Science
1.3 The term “scanning electron microscopy” occasionally
refers to the entire analytical system including energy disper-
3. Terminology
siveX-rayspectrometry(EDS)orwavelengthdispersiveX-ray
3.1 Definitions—For additional terms commonly employed
spectrometry (WDS) or both.
for general forensic examinations, see Terminology E1732.
1.4 This guide does not cover the theoretical aspects of
3.1.1 background X-rays (Bremsstrahlung, braking
many of the topics presented.
radiation, continuous spectrum), n—nonspecific X-ray radia-
tion with a continuous energy range from zero up to the beam
1.5 This guide cannot replace knowledge, skill, or ability
voltage in which background radiation results from the decel-
acquired through appropriate education, training, and experi-
eration of beam electrons in the atomic Coulombic field.
ence and should be used in conjunction with sound profes-
3.1.1.1 Discussion—A typical X-ray spectrum consists of
sional judgment.
both a continuous background and peaks from characteristic
1.6 The values stated in SI units are to be regarded as X-rays.
standard. No other units of measurement are included in this
3.1.2 backscattered electrons, n—primary beam electrons
standard.
that are scattered from the sample after undergoing few
inelastic interactions.
1.7 This standard does not purport to address all of the
3.1.2.1 Discussion—The probability of backscattering is
safety concerns, if any, associated with its use. It is the
proportional to the atomic number.
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter- 3.1.3 bulk analysis, n—type of scanning electron micros-
mine the applicability of regulatory limitations prior to use.
copy (SEM) analysis that determines the average elemental
composition of a material in which the area of analysis is as
1.8 This international standard was developed in accor-
large as possible and may be achieved by a single large area
dance with internationally recognized principles on standard-
rasterorthesummedresultsfrommultiplesmallerarearasters.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
3.1.4 cathodoluminescence, n—emission of photons in the
mendations issued by the World Trade Organization Technical ultraviolet (UV), visible (Vis), and infrared (IR) regions of the
Barriers to Trade (TBT) Committee.
electromagnetic spectrum as a result of electron beam interac-
tion with certain materials.
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This guide is under the jurisdiction of ASTM Committee E30 on Forensic
2
Sciences and are the direct responsibility of Subcommittee E30.01 on Criminalis- For referenced ASTM standards, visit the ASTM website, www.astm.org, or
tics. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Current edition approved Feb. 15, 2013. Published April 2013. DOI: 10.1520/ Standards volume information, refer to the standard’s Document Summary page on
E2809-13. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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E2809 − 13
3.1.5 characteristic X-rays, n—X-ray emission resulting 3.1.14 interaction volume, n—sample volume in which the
from de-excitation of an atom following inner shell ionization electron beam loses most of its energy.
in which the energy of the X-rays is related to the atomic
3.1.14.1 Discussion—It is generally thought of as the vol-
number of the atom, providing the basis for energy dispersive ume
...
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