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Ar-37 has been prepared from micron- and nano- diameter CaO by irradiation in the predominantly thermal flux of a SLOWPOKE-2 reactor. A polyether ether ketone irradiation vial facilitates irradiation in vacuo to yield radio-argon as the sole gaseous product. Gamma-emitting Ar-41(T1/2 = 110 min) is used to infer Ar-37 activity, although 40Ar(n, γ)41Ar also occurs as a result of air entrapped within the CaO matrix. Less air is present in the nano-CaO matrix and more radio-argon is liberated to the gas phase. Using nano-CaO, 96 ± 10% of predicted Ar-41 is observed following Ar-41 diffusion to an un-irradiated container.

In a recent international exercise, 10 international nuclear forensics laboratories successfully performed radiochronometry on three low enriched uranium oxide samples, providing 12 analytical results using three different parent-daughter pairs serving as independent chronometers. The vast majority of the results were consistent with one another and consistent with the known processing history of the materials. In general, for these particular samples, mass spectrometry gave more accurate and more precise analytical results than decay counting measurements. In addition, the concordance of the 235U–231Pa and 234U–230Th chronometers confirmed the validity of the age dating assumptions, increasing confidence in the resulting conclusions.

Physical characterization is one of the most broad and important categories of techniques to apply in a nuclear forensic examination. Physical characterization techniques vary from simple weighing and dimensional measurements to complex sample preparation and scanning electron microscopy-electron backscatter diffraction analysis. This paper reports on the physical characterization conducted by several international laboratories participating in the fourth Collaborative Materials Exercise, organized by the Nuclear Forensics International Technical Working Group. Methods include a range of physical measurements, microscopy-based observations, and profilometry. The value of these results for addressing key investigative questions concerning two uranium dioxide pellets and a uranium dioxide powder is discussed.

The lowest-observed-adverse-effect and no-observed-adverse-effect concentrations of sarin were determined in soils typical to Canada and Russia. Maximum acceptable concentrations were established to be 3.0 × 10−4 mg kg−1 for the standard reference soil, 2.0 × 10−3 mg kg−1 for prairie soil, and 1.0 × 10−2 mg kg−1 for forest soil.

Throughout much of their history, enzymes secreted by microorganisms were used in the process of fermentation to produce and preserve food products. Fermented foods such as cheese, yogurt, and bread have been crucial to the development of modern civilization. Over time, advances in science and engineering have allowed the isolation of novel enzymes and characterization of their properties. As a result, applications of these biological molecules have increased dramatically in the past three decades as they are used routinely nowadays and form the cornerstone of all major industries of the 20th century. The use of enzymes in the manufacturing industries is not only beneficial for the consumers but it also replaces the use of harsh chemicals detrimental to the environment with green alternatives. In this chapter, we introduce the reader to pioneering omics approaches that aid in the discovery of new enzymes with unique functions or aid in optimizing current ones for higher yield, selectivity, and/or improved usage. Finally, we illustrate some examples of enzymes that were already targeted by molecular bioengineering and refined for commercial applications.

An analytical procedure for determining the relative amounts of ⁶⁰Co and its ⁶⁰Ni daughter in a radioactive cobalt source by means of chromatographic separation and radiometric and mass spectrometric detection was developed, optimized and assessed through two round robin exercises for nuclear forensic investigations. Solid phase extraction (EXC) using Ni resin (Eichrom) and ion exchange (IEC) using Dowex-1X8 (Acros Organics) chromatographic approaches were considered for separating Co and Ni. Decontamination factors of 25 and 2.8 × 10&#8310 were measured for EXC and IEC, respectively. Based on those results, only the IEC option was pursued. The effects of particle size, mass of resin, and degree of cross-linkage for decontamination performance were assessed, and the loading/eluting conditions were optimized. Canadian (CNSC, RPB, UL, RMC, AECL) and American (ANL) laboratories participated in two round robin exercises designed by the National Research Council of Canada to determine the suitability and limitations of the proposed methods. Age determination for freshly irradiated sources (

Chemical warfare agents have been stockpiled for almost a decade and their destruction has become an environmental issue that will continue to require attention for many years. There are hundreds of thousands of tonnes yet to be destroyed, and the current chemical or incineration techniques are not without problems. While many researchers are seeking better chemical techniques, we decided to try ionizing radiation to destroy sulphur mustard with the goal of producing non-toxic products. We irradiated a variety of sulphur mustard samples by both a mixed field source (β, γ and neutrons) and a pure gamma source. The mixed field irradiation of wet sulphur mustard for long irradiation times was the most successful at destroying the chemical agent.