Australian Nuclear Science and Technology Organisation

Australian Nuclear Science and Technology Organization

David Boardman

Adam Sarbutt

Alison Flynn

Dale Prokopovich

Mark Reinhard

Mathew Guenette

Lachlan Chartier

Jayden Ilter

Geoff Watt

A coded mask apparatus is provided for gamma rays. The apparatus uses nested masks, at least one of which rotates relative to the other.

Gamma-ray imaging

A mask for use in compressed sensing of incoming radiation includes a material that modulates an intensity of incoming radiation, a plurality of mask aperture regions, and one or more axes of rotational symmetry with respect to the mask aperture regions. Each mask aperture region includes at least one mask aperture that allows a higher transmission of the incoming radiation relative to other portions of the mask aperture region. The relative transmission sufficient to allow a reconstruction of compressed sensing measurements and has a shape that provides a symmetry under rotation about the one or more axes of rotational symmetry. A mutual coherence of a sensing matrix generated by a rotation of the plurality of mask aperture regions is less than one. An imaging system for compressed sensing of incoming radiation including such a mask is also provided.

Compressive imaging method and system comprising a detector, a mask, and a drive for rotating the mask about at least one of one or more axes of rotational symmetry

Described herein is a method of processing a gamma ray spectrum acquired from a target. The method comprises determining whether the gamma ray spectrum of the target belongs to a first class of a plurality of classes, the first class containing reference gamma ray spectra of one or more radionuclide sources of interest, using optimal loading coefficients associated with the one or more radionuclide sources of interest, wherein the optimal loading coefficients have been obtained using Fisher linear discriminant analysis, and generating an output signal dependent on the determining.

Radionuclide detection and identification

Described herein is a method for determining the presence or absence of anomalous radioactive materials in a target in a detection zone. In the method, a target gamma ray spectrum is obtained from the target and a target data set is prepared from the target gamma ray spectrum. This data set comprise a plurality of intensity values, each intensity value being associated with an energy bin representing a gamma ray energy or range of gamma ray energies in the target gamma ray spectrum. The target data set is then pre-processed and projected into a principal component space which contains a pre-processed data library projected into the principal component space. A distance is then determined between the projected pre-processed target data set and one or more clusters of the projected pre-processed data library in the principal component space and this distance is compared with a predetermined threshold distance so as to determine if an anomalous radioactive material is present in the target.

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Lucas Heights, Australia

David Boardman