In situ position-resolved x-ray diffraction of an intact Roman-era Egyptian mummy guided by computed tomography

S. R. Stock*, M. K. Stock, J. D. Almer

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations

Abstract

Contrast in Computed Tomography (CT) most often relies on absorption differences, and reconstructions give absorptivity of each volume element (voxel) but not the material's identity. This paper describes the first use of in situ position-resolved x-ray diffraction to identify different contents (see below) within an intact mummy. Hawara Portrait Mummy No. 4 (HPM4) was first imaged with a clinical CT scanner, and this 3D "roadmap" guided diffraction mapping at beamline 1-ID of the Advanced Photon Source. Only 24 hrs were available, and the CT data allowed mapping of only the volumes of interest. The long beam path through the mummy was a major complication solved by collecting each diffraction pattern at two detector-mummy separations. Accuracy in diffracting volume positions was 1-2 mm, and precision sufficed for diffraction identification of the materials. Diffraction patterns were collected from the mineralized tissues within the five year old child's mummy (HPM4), specifically the skull, cervical vertebrae, femora and teeth. Patterns from the femorum lateral and medial sides (and the skull's left and right sides) could be analyzed separately. Lattice parameters and crystallite sizes of the bones' mineral phase were comparable with those from modern bone. Within the wrappings, wires were located by diffraction and identified as a modern dual phase steel, probably introduced during earlier conservation. Highly absorbing, millimeter-sized inclusions were identified as calcite. The position of these and other features were found at the positions indicated by the CT scans, and the limitations of the diffraction approach compared to absorption CT are discussed.

Original languageEnglish (US)
Title of host publicationDevelopments in X-Ray Tomography XII
EditorsBert Muller, Ge Wang
PublisherSPIE
ISBN (Electronic)9781510629196
DOIs
StatePublished - Jan 1 2019
Event12th SPIE Conference on Developments in X-Ray Tomography 2019 - San Diego, United States
Duration: Aug 13 2019Aug 15 2019

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume11113
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X

Conference

Conference12th SPIE Conference on Developments in X-Ray Tomography 2019
CountryUnited States
CitySan Diego
Period8/13/198/15/19

Keywords

  • Clinical CT
  • Egyptian mummy
  • Synchrotron x-radiation
  • X-ray diffraction

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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