an x-ray spectral database for forensic applications€¦ · an x-ray spectral database for...

AN X-RAY SPECTRAL DATABASE FOR

FORENSIC APPLICATIONS

Dennis WardFederal Bureau of Investigation

Quantico, DC 22135

denniscward@earthlink.net703.632.7424

Characterize

Compare

Identify

What are the structural and chemical characteristics?

Could items have come from the same source?

What is it?

Existing Deficiencies in SEM/XRF Utilities

• “Quant based”• Cannot search for best fit• Cannot compare specific compositions • Cannot search for text information• Cannot display nested spectra• Cannot associate an image with

spectrum

Spectrum Analysis WindowSpectrum Analysis Window

Select Search CriteriaSelect Search Criteria

Best Fit SearchBest Fit Search

Compare Case SpectraCompare Case Spectra

• Demonstrate GSR particle populations• Demonstrate “other” populations • “Unusual” particle composition query• Bullet lead/jacket composition “screen”

Summary of uses(GSR/Firearms)

Individual recordIndividual record

“Projects”“Projects”(Speer Lawman 9mm Luger)

“Best fit” query“Best fit” queryExample: Winchester Super Clean NT primer cup

Query for specific compositionQuery for specific compositionExample: Example: SbSb >5%>5% SbSb, , BaBa >5% >5%

view GSR populationview GSR populationExample: Winchester 25 auto

“environmental” particle composition“environmental” particle compositionExample: Brake particles

Confirm questioned particle to GSRConfirm questioned particle to GSR

SWGFAX(Scientific Working Group for the Forensic

Archive of X-ray spectra)

• Belgium, US, Germany, Canada, and California

• Confirmed utility of database• Consensus for design

♦ MATERIAL IDENTIFICATION ♦ PRODUCT IDENTIFICATION♦ MANUFACTURER IDENTIFICATION♦ CRITICAL SUDIES OF COMPOSITION

♦ FBI LABORATORY♦ FEDERAL LABORATORIES♦ INDUSTRY♦ STATE AND LOCAL CRIME LABORATORIES

NATIONAL XNATIONAL X--RAY DATABASERAY DATABASE(PROPOSED FOR DEVELOPMENT)

Spectral Library and Classification Explorer, developed by the FBI and xk, Inc. as a “stand alone” application for spectra management

Scanning Electron Microscope

X-ray Fluorescence - laboratory use

X-ray Fluorescence - field use

(proposed for development)

SS 316

SEM/EDS

SS330.str

Fe

Cr

Ni

Cr, (Mn) Fe

Ni????

SS 330

0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00 20.00

SS 316 XRF

SS 316 Micro

First response capability

• Elemental analysis• Wide elemental range (Mg +)• Qualitative• Portable (suitcase size)• Interface to database (SLICE)• = XRF

www.fbi.gov

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