Combined computed tomography and position-resolved X-ray diffraction of an intact Roman-era Egyptian portrait mummy

Abstract

Hawara Portrait Mummy 4, a Roman-era Egyptian portrait mummy, was studied with computed tomography (CT) and with CT-guided synchrotron X-ray diffraction mapping. These are the first X-ray diffraction results obtained non-invasively from objects within a mummy. The CT data showed human remains of a 5-year-old child, consistent with the female (but not the age) depicted on the portrait. Physical trauma was not evident in the skeleton. Diffraction at two different mummy-to-detector separations allowed volumetric mapping of features including wires and inclusions within the wrappings and the skull and femora. The largest uncertainty in origin determination was approximately 1.5 mm along the X-ray beam direction, and diffraction- and CT-determined positions matched. Diffraction showed that the wires were a modern dual-phase steel and showed that the 7 × 5 × 3 mm inclusion ventral of the abdomen was calcite. Tracing the 00.2 and 00.4 carbonated apatite (bone's crystalline phase) reflections back to their origins produced cross-sectional maps of the skull and of femora; these maps agreed with transverse CT slices within approximately 1 mm. Coupling CT and position-resolved X-ray diffraction, therefore, offers considerable promise for non-invasive studies of mummies.

X-ray imaging meets deep learning

“…A preliminary report of the studies on HPM4 appeared in the exhibit volume 8 and a fuller report in the archival literature. 9 The methods and the principles underlying these methods are covered briefly below, and the CT and x-ray diffraction results are presented as well. Implicit in the statement of the three contexts are a number of questions, and the extent to which these were answered is one focus and a second is what improved methods might allow us to learn in the future.…”

“…Most of the details of the experiment are reported elsewhere. 9 The x-ray area detector (Dexela 2923 CMOS detector; 3888 x 3072 pixels, 75 μm pixel pitch) was nominally perpendicular to and centered on the incident x-ray beam and mounted on a translator allowing the specimen -detector separation to be varied. Using the 3D CT roadmap, diffraction patterns covered the objects of interest by translating HPM4 vertically and horizontally across the beam.…”

“…Wires are shown in green, and the white arrow shows wires which were not visible in (a). Adapted from 9 . and the shape of the feature typically does not change.…”

“…This composition of calcite matches that of local quarries operating when HPM4 was made. 21 Adapted from 9 .…”

“…Some are well dispersed and other are closely spaced. 9 One suspects that q1, q2 and several other inclusions with similar contrast are limestone debris, mainly calcite with admixture of variable amounts of other, less absorbing mineral phases.…”