C Christodoulou

Publications (2)3.74 Total impact

• Article: Explosive detection using pixellated X-ray diffraction (PixD)

  D O'Flynn, C B Reid, C Christodoulou, M D Wilson, M C Veale, P Seller, D Hills, H Desai, B Wong, R Speller
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  ABSTRACT: A novel, pixellated, energy-resolving X-ray detector has been utilised to simultaneously combine angular and energy dispersive X-ray diffraction (XRD). This approach allows a system to measure XRD data using the benefits of both approaches. Data acquisition is fast, and the system contains no moving parts, making it ideal for applications in security, particularly for the detection of explosive materials hidden within packages or baggage. Explosive samples supplied by the Centre for Applied Science and Technology, U.K. were examined using the pixellated diffraction technique, and the XRD data were compared with those from inert materials typically found inside luggage. A method of processing the data was developed, which greatly reduces the amount of data outputted from the detector whilst preserving the angular and energy resolution. Using principal component and discriminant analyses, a model was developed which predicts the correct classification of an unknown sample as either ``explosive'' or ``inert'' for data with acquisition times as low as one second.
  Journal of Instrumentation 03/2013; 8:P03007. · 1.87 Impact Factor
• Source

  Available from: Matthew C. Veale

  Article: Pixellated Cd(Zn)Te high-energy X-ray instrument.

  P Seller, S Bell, R J Cernik, C Christodoulou, C K Egan, J A Gaskin, S Jacques, S Pani, B D Ramsey, C Reid, P J Sellin, J W Scuffham, R D Speller, M D Wilson, M C Veale
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  ABSTRACT: We have developed a pixellated high energy X-ray detector instrument to be used in a variety of imaging applications. The instrument consists of either a Cadmium Zinc Telluride or Cadmium Telluride (Cd(Zn)Te) detector bump-bonded to a large area ASIC and packaged with a high performance data acquisition system. The 80 by 80 pixels each of 250 μm by 250 μm give better than 1 keV FWHM energy resolution at 59.5 keV and 1.5 keV FWHM at 141 keV, at the same time providing a high speed imaging performance. This system uses a relatively simple wire-bonded interconnection scheme but this is being upgraded to allow multiple modules to be used with very small dead space. The readout system and the novel interconnect technology is described and how the system is performing in several target applications.
  Journal of Instrumentation 12/2011; 6(12). · 1.87 Impact Factor