Passive standoff detection of radiological products in the thermal infrared regio

摘要

An investigation is made into the possibility of applying the passive standoff detection technique to the identification of radiological and related products. This work is based on laboratory measurements of the diffuse reflectance from a number of radiological or related products, including U_3O_8, ThO_2, CsI, SrO, I_2O_5 and La_2O_3. With the use of these measured reflectances, simulations of the nadir radiances with the various types of surface reflectances were carried out with the MODTRAN4 transmission model. The simulations were performed for two types of scenarios; at an altitude of 1 m above the ground for the purpose of simulating the passive detection of nuclear products with a hand-held instrument, and at an altitude of 1 km to emulate the conditions of a passive sensor carried aloft in an aircraft. The results of the simulations under idealized conditions show that there is a good potential for being able to measure radiological products or related materials by passive standoff detection using Fourier-transform infrared radiometric techniques.