Transition Metal Oxides (TMOs) are being developed for applications in medical ionising radiation safety and
dosimetry. These materials exhibit a variety of properties, which must be fully understood in order to fully utilise their
potential as novel photovoltaic sensors. TMOs have semi-conducting properties, showing either n-type or p-type
characteristics. Thus, p-n junction diodes can be built by combining specific TMOs. Moreover, the TMOs exhibit other
highly useful properties: they function successfully as semiconductors at room temperature, and they are cheap and
simple to manufacture compared to many other semiconductors. The sensor manufacturing process involves a flamespraying
material deposition mechanism onto the substrate to form the sensor. This paper assesses the performance of
the TMO materials and then addresses their possible applications after their full optimisation has been carried out.
Analysis of the charge transport mechanism of the TMO sensors has been carried out with a view to improving their
efficiency and signal-to-noise ratio. Further to this, analysis of the structure and properties of the TMOs has been carried
out through electron microscopy. This analysis has indicated solutions to current
Illicit drugs are imported into countries in myriad ways, including via the postal system and courier services. An
automated system is required to detect drugs in parcels for which X-ray diffraction is a suitable technique as it is
non-destructive, material specific and uses X-rays of sufficiently high energy to penetrate parcels containing a
range of attenuating materials. A database has been constructed containing the measured powder diffraction
profiles of several thousand materials likely to be found in parcels. These include drugs, cutting agents,
packaging and other innocuous materials. A software model has been developed using these data to predict the
diffraction profiles which would be obtained by X-ray diffraction systems with a range of suggested detector
(high purity germanium, CZT and scintillation), source and collimation options. The aim of the model was to
identify the most promising system geometries, which was done with the aid of multivariate analysis (MVA). The
most promising systems were constructed and tested. The diffraction profiles of a range of materials have been
measured and used to both validate the model and to identify the presence of drugs in sample packages.
Laser Doppler Anemometry (LDA) and Particle Image Velocimetry (PIV) are commonly used in the analysis of
particulates in fluid flows. Despite the successes of these techniques, current instrumentation has placed limitations on
the size and shape of the particles undergoing measurement, thus restricting the available data for the many industrial
processes now utilising nano/micro particles. Data for spherical and irregularly shaped particles down to the order of 0.1
µm is now urgently required. Therefore, an ultra-fast LDA-PIV system is being constructed for the acquisition of this
data.
A key component of this instrument is the PIV optical detection system. Both the size and speed of the particles under
investigation place challenging constraints on the system specifications: magnification is required within the system in
order to visualise particles of the size of interest, but this restricts the corresponding field of view in a linearly inverse
manner. Thus, for several images of a single particle in a fast fluid flow to be obtained, the image capture rate and
sensitivity of the system must be sufficiently high.
In order to fulfil the instrumentation criteria, the optical detection system chosen is a high-speed, lensed, digital imaging
system based on state-of-the-art CMOS technology - the 'Vanilla' sensor developed by the UK based MI3 consortium.
This novel Active Pixel Sensor is capable of high frame rates and sparse readout. When coupled with an image
intensifier, it will have single photon detection capabilities. An FPGA based DAQ will allow real-time operation with
minimal data transfer.
R. Longo, A. Asimidis, D. Cavouras, C. Esbrand, A. Fant, P. Gasiorek, H. Georgiou, G. Hall, J. Jones, J. Leaver, G. Li, J. Griffiths, D. Machin, N. Manthos, M. Metaxas, M. Noy, J. Østby, F. Psomadellis, T. Rokvic, G. Royle, H. Schulerud, R. Speller, PF. van der Stelt, S. Theodoridis, F. Triantis, R. Turchetta, C. Venanzi
I-ImaS (Intelligent Imaging Sensors) is a European project aiming to produce adaptive x-ray imaging systems using Monolithic Active Pixel Sensors (MAPS) to create optimal diagnostic images. Initial systems concentrate on mammography and cephalography.
The on-chip intelligence available to MAPS technology will allow real-time analysis of data during image acquisition, giving the capability to build a truly adaptive imaging system with the potential to create images with maximum diagnostic information within given dose constraints.
In our system, the exposure in each image region is optimized and the beam intensity is a function not only of tissue thickness and attenuation, but also of local physical and statistical parameters found in the image itself. Using a linear array of detectors with on-chip intelligence, the system will perform an on-line analysis of the image during the scan and then will optimize the X-ray intensity in order to obtain the maximum diagnostic information from the region of interest while minimizing exposure of less important, or simply less dense, regions.
This paper summarizes the testing of the sensors and their electronics carried out using synchrotron radiation, x-ray sources and optical measurements.
The sensors are tiled to form a 1.5D linear array. These have been characterised and appropriate correction techniques formulated to take into account misalignments between individual sensors.
Full testing of the mammography and cephalography I-ImaS prototypes is now underway and the system intelligence is constantly being upgraded through iterative testing in order to obtain the optimal algorithms and settings.
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