Authors:T. Cousins, T. Jones, J. Brisson, J. McFee, T. Jamieson, E. Waller, F. LeMay, H. Ing, E. Clifford, and E. Selkirk
In order to detect and locate buried landmines for peacekeeping, the Canadian Department of National Defence (DND), under
the Improved Landmine Detection Project, is developing a vehicle-mounted, two-phase mine detection system. The first phase
constitutes a suite of detectors used to indicate the possibility of a mine at a particular location (to ±30 cm in accuracy).
In the second phase a Thermal Neutron Activation (TNA) system is used to confirm the presence of explosives via detection
of the 10.83 MeV gamma-ray associated with nitrogen decay. The TNA system developed for this uses a 100 μg252Cf neutron source surrounded by four 3″×3″ NaI(Tl) detectors. Combining the use of state-of-the art radiation transport codes
for design, judicious choice of specialized shielding materials and development of high-rate, fast-pulse processing electronics,
has led to a system which can; (i) confirm the presence of all surface- or lightly-buried anti-tank mines in a few seconds
to a minute (depending on mass of explosive), (ii) confirm the presence of anti-tank mines down to 20 cm depth in less than
5 minutes, (iii) confirm the presence of large (>100 g nitrogen) anti-personnel mines in less than five minutes, (iv) operate
in adverse climatic conditions. These results have been verified in field trials and the system is due to be fielded in 1999.
Authors:W. Andrews, E. Waller, P. Brousseau, G. Roy, X. Cao, K. Creber, and L. Erhardt
During the past decade, interest has increased in qualifying and quantifying the threat posed to the public by the illegal
use of radionuclides. In order to take investigations beyond the laboratory bench into more realistic scenarios, environmental
and safety considerations dictate that these studies be performed on stable and benign surrogates. This paper discusses some
of these studies, specifically the use of cerium dioxide for actinide ceramics and calcium and natural strontium ceramics
for those based on 90Sr.
Authors:Weijia Li, R. Skinner, K. Megna, Jing Chen, S. Perera, J. Murimboh, E. Waller, L. Erhardt, and R. Cornett
Inhalation is one of the most important routes for aerosol particles of uranium compounds to enter the body. The main step
for uranium to be available for blood circulation and for interaction with bio-molecules is the dissolution of the particles.
Particle size effects on dissolution of uranium dioxide and uranium ore were studied in simulated lung fluid using the “batch/filter”
method. Samples were fractionated to ten size ranges from <0.43 μm to >10 μm by cascade impaction prior to dissolution experiments.
Dependence of dissolution kinetics on particle size and on the amount of uranium trioxide contained in the particles was observed.