Radiation Safety of X-ray based mineral sorting machines

X-ray transmission systems widely used in the recycling, inspection and NDT fields produce X-ray radiographs which are then automatically analysed to enable identification and separation of materials. Not often reported is the safety considerations that go into the design and evaluation of such machines. In this paper we discuss radiation safety aspects of De Beers' X-ray based sorting machines, design considerations, evaluation and testing, monitoring systems, regulatory requirements and potential theoretical modeling. Examples of X-ray based sorting machines will be used to illustrate these radiation safety issues.