Standoff alpha radiation detection for hot cell imaging and crime scene investigation

Optical Review - This paper presents the remote detection of alpha contamination in a nuclear facility. Alpha-active material in a shielded nuclear radiation containment chamber has been localized...     

Measurement of the <Superscript>231</Superscript>Pa/<Superscript>235</Superscript>U ratio for the age determination of uranium materials

The paper describes the age (production date) determination of uranium reference materials using the ²³¹Pa/²³⁵U ratio. Direct addition of ²³⁷Np in secular equilibrium with its ²³³Pa daughter was chosen instead of the regular milking of ²³⁷Np to avoid possible loss of Pa. Sample preparation consists of a fast, one-step procedure. The developed method using ICP-MS for the measurement of ²³¹Pa is more precise than alpha spectrometry and is applicable for freshly produced low-enriched uranium materials. The measured ages are in good agreement with the reported production dates, thus the ²³¹Pa/²³⁵U chronometer can be applied for validation of ²³⁰Th/²³⁴U in nuclear forensics and safeguards.     

Collection and behaviour of radon progenies on thin Mylar foils

Thin Mylar foils are often used to protect detectors from contamination. However, these foils can be electrostatically charged, possibly leading to their contamination with airborne radon progenies. In the present work, the collection and behaviour of radon progenies on Mylar foils was investigated in detail using alpha spectrometry. The radon progenies collection rate of a small Mylar foil (3 cm²) is equivalent to an air sampler with a flow rate of approximately 0.1 m³/h. It was demonstrated that such contamination may jeopardise the validity of the entire analysis if not interpreted correctly.     

Characterization of an Irish Sea radioactively contaminated marine sediment core by radiometric and mass spectrometric techniques

Summary A radioactively contaminated marine sediment core stemming from Irish Sea has been characterized by radiometric and mass spectrometric techniques as for ²³⁷Np, ²⁴¹Am, ²³⁹Pu, ²⁴⁰Pu, ²⁴¹Pu, ¹³⁷Cs and ¹⁵⁴Eu. The data obtained with independent methods in the framework of a QA/QC program as compared with the source term discharges, as well as with those reported in literature, are in good agreement.     

A combined method for the determination of the isotopic vector of plutonium isotopes in environmental samples

A combination of alpha-spectrometry, liquid scintillation counting (LSC) and accelerator mass spectrometry (AMS) was used for the determination of plutonium isotopes. ²³⁸Pu and ^239+240Pu were measured by alpha-spectrometry after separation of Pu by anion-exchange using ²³⁶Pu tracer as recovery monitor. After alpha-measurement, one part of the sample was dissolved for determining ²⁴¹Pu by LSC. Another part was used for the measurement of the ²⁴⁰Pu/²³⁹Pu atom ratio by AMS at VERA. Thus, it was possible to obtain complete information on the Pu isotopic composition of the samples. This method was applied to environmental reference samples and samples contaminated from nuclear reprocessing.