Open Access Te Herenga Waka-Victoria University of Wellington
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Radiation Imaging with Caesium Bromide Storage Phosphors

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posted on 2021-11-13, 11:39 authored by Winch, Nicola Maree

This thesis is centred on the development of a new method to prepare semitransparent CsBr:Eu²⁺ imaging plates for high resolution X-ray radiography. Methods of characterising the performance of these plates, and their application to dual energy imaging and neutron imaging are discussed. The basic preparation method, based on high-pressure uniaxial compression of powder mixtures of CsBr and EuBr₂, produces imaging plates which show good transparency and resolution. These imaging plates have a conversion efficiency of 1.5 pJmR⁻¹mm⁻³ compared to 5.1 pJmR⁻¹mm⁻³ for a commercial needle imaging plate. Water is found to play a critical role in the photostimulated luminescence activation in CsBr:Eu²⁺ storage phosphors, and imaging plates subsequently hydrated at room temperature have an increased conversion efficiency of up to 11 pJmR⁻¹mm⁻³, better than the commercial material. A model has been suggested for the generation of the PSL active site in the imaging plates based on thermomechanical sintering and water-induced crystal regrowth. A precise method for determining the conversion efficiency and stimulation energy of X-ray storage phosphor materials using an integrating sphere has been developed and used to characterise the materials developed in this thesis. A novel read-out method for storage phosphor imaging plates based on flood illumination and a semi-professional digital camera has also been developed and tested. Good quality X-ray images are obtained and the method shows excellent promise as a low-cost, portable X-ray imaging system. A stratified detector using CsBr imaging plates has been developed for use in dual-energy imaging. Results suggest that it is possible to perform dual-energy imaging with this structure. CsBr:Eu²⁺ imaging plates have been produced with added neutron converters for use as thermal neutron imaging plates. An imaging plate with 5 % ¹ºB₂O₃ added as a neutron converter has a PSL output 50 % that of a commercial neutron imaging plate. Neutron imaging with these imaging plates has been successfully demonstrated.


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Date of Award



Te Herenga Waka—Victoria University of Wellington

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Author Retains Copyright

Degree Discipline


Degree Grantor

Te Herenga Waka—Victoria University of Wellington

Degree Level


Degree Name

Doctor of Philosophy

Victoria University of Wellington Item Type

Awarded Doctoral Thesis



Victoria University of Wellington School

School of Chemical and Physical Sciences


Edgar, Andy; Bartle, Murray