Previous work in collaboration with the Canada Centre for Remote Sensing (CCRS) and the Australian Safeguards and Non-proliferation Office (ASNO) has demonstrated the potential application of spectral information in terrain and vegetation classification; water usage (and by inference certain mining or milling operations); and geographic movements of ore material on the site by spectral discrimination. This work has been performed in conjunction with hyperspectral imaging (HIS) sensors that operate on airborne platforms (e.g., Canadian Compact Airborne Spectrographic Imager (CASI) instrument and Australian Probe-1) and satellite platforms (e.g., Hyperion satellite). Currently, HIS sensors such as these operate only in the visible and near-infrared region of the spectrum. This paper describes a joint project between Defence Research and Development Canada (DRDC) – Valcartier and the Canadian Safeguards Support Program (CSSP), which examines the possibility of applying a similar detection technique to the identification of nuclear materials based on the measurement of the spectral signature of the material in the thermal infrared region. Previously, we have shown from Fourier-transform infrared spectroscopic measurements made in the laboratory, that radiological materials such as SrO, I I2O5, ThO , ThO2, La , La2O3 and yellow cake exhibit detailed infrared signatures in the transparent atmospheric window region (8 – 13 microns) of the thermal infrared spectrum. From a series of simulations using the radiative transfer model MODTRAN4, it also has been shown that these materials have a high potential of being detected from altitudes of 1 m to 1 km above the earth’s surface. In this paper we present results of our current work that focus on recent new measurements of spectral signatures, including those of the uranium oxides UO UO2, UO , UO3 and U U3O8. Remote sensing results from a recent campaign at DRDC – Valcartier are also presented which address the passive detection of radiological materials in the field at standoff distances of 10 – 60 m. These results are analysed in view of determining the potential for measuring nuclear products with a passive standoff FTIR technique. The development of a passive detection capability based on FTIR radiometry may provide a significant addition to the visible and NIR HIS tools that currently exist for detecting and identifying NBC threats. .
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