***N.B Applications are no longer being considered for this project***
Contact: Dr Sarah Heath
Separation chemistry is essential in the forensic analysis of nuclear materials. Rapid and selective techniques allow for high confidence in the analysis obtained from the material and can allow for the quantification of radioisotopes. Traditional separation schemes may not be suitable for all samples. For example americium and lanthanides are usually purified towards the end of separation schemes after all other elements have been removed. This not satisfactory for radionuclides with short half lives. These analyses allow for a dataset to be gathered which can be used to determine the origin and intended use of nuclear materials.
Extraction chromatography has allowed the rapid separation of specific isotopes in nuclear forensics in recent times. This PhD will work to develop novel, rapid separation and preparation of samples suitable for alpha and gamma spectrometry for important radioisotopes of interest in a nuclear forensic investigation. Specifically the minor actinides Am and Cm and fission, daughter and activation products.
The work will utilise radiochemistry techniques to design, test and then apply selective species to complex forensic matrices to develop additional rapid and selective processes, including possible incorporation into the quantification of the sample.
Extraction chromatography in radiochemistry has allowed for the rapid separation of specific isotopes of interest in nuclear forensics. The design of elaborate extraction schemes to achieve difficult separations on small samples is an area of active research. Automation and vacuum flow systems are allowing for easier, rapid separations to be achieved on complex or smaller samples sizes; allowing for larger datasets to be obtained. These datasets are essential for modelling materials in nuclear forensics.
Schemes have been developed for a number of essential isotopes, e.g. U, Pu, Np, Sr and Cs. Currently, specific fingerprint isotopes require laborious extraction techniques which may hinder the ability to measure them from complex matrices where a complete dataset is required.
An example of this is Am and Cm, which in complex matrices can require long separation processes to separate them from the Lanthanide series. Many fission products can also be problematic and well as daughter and granddaughter chronometers (e.g. Cd, Pa, Th). Extractants have been developed which are highly selective for Am, Cm and fission/activation products of interest in the wider literature. These extractants will be adsorbed to polymeric matrices and developed as potential extraction chromatography resins to augment current schemes and to attempt to extract the elements on to a matrix which can be used for direct quantitative measurements.
The potential improvements of further rapid selective schemes will allow essential data to be obtained as quickly as possible on a forensic sample. These can then be used in tandem with other available materials and automation systems. The overall rapid separation scheme will be investigated to identify improvements and develop specific targeted extractants applied to nuclear forensic matrices.