Nanoscale Ex Situ Thermal Impulse Sensors for Structural Fire Forensics

• NCJ Number: 253123
• Award: Temperature Sensors Embedded in Paint for Fire Debris Analysis and Arson Scene Investigations

Annotation

This study developed nanoscale ex situ thermal impulse (i.e., the temperature and duration of a heating event) sensors for structural fire forensics, using a mixture of two lanthanide-doped oxide precursors (precursor Eu:ZrO2 and precursor Dy:Y2O3) that undergo irreversible phase changes when heated.

Abstract

These changes were probed using photoluminescence (PL) spectroscopy, with the PL spectra being dependent on the thermal impulse (TI) experienced by the sensors. By correlating the PL spectra to different in-lab TIs, researchers produced a spectroscopic calibration for the sensors. This calibration enabled the determination of an unknown TI of a heating event, using only the PL spectrum of the heated TI sensors. This study reports on the calibration of these sensors for isothermal heating durations up to 600 s and isothermal temperatures up to 1273 K. Using this calibration, the study also demonstrated the sensors ability to determine an unknown TI and determine their functionality when dispersed into paint, which is heated in the presence of drywall. (publisher abstract modified)