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- del Risco Norrlid, Lilián, 1969-
(författare)
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Modeling the Performance of a Hybrid Pixel Detector for Digital X-ray Imaging
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The development of digital detectors for X-ray imaging in medical diagnostics receives an increasing amount of attention. The detector under development at the Department of Radiation Sciences at Uppsala University is a hybrid pixel detector, which consists of a semiconductor sensor mounted onto a readout chip. The readout chip is capable of performing photon counting and has an externally adjustable threshold.A simulation tool for the detector and a model applying the linear-systems transfer theory to X-ray hybrid pixel detectors have been developed. Also a characterization of the readout chip has been done. In order to estimate the potential of the detector for diagnostic radiology, we investigate the image quality using the spatial frequency dependent detective quantum efficiency (DQE). By means of the detector simulations, the influence of threshold setting, noise sources, level of exposure and charge sharing on the DQE have been studied. By means of the linear-systems theory, a single analytical expression is provided to obtain the DQE of a hybrid pixel detector.The method developed in this thesis will make it possible to optimize a detector design according to a particular medical application. It will also permit modifications and new features to be included without having to construct a full detector system.
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- Edling, Fredrik, et al.
(författare)
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Performance of a chip for hybrid pixel detectors with two counters for X-ray imaging
- 2004
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Ingår i: Proceedings of the 5th International Workshop on Radiation Imaging Detectors. - : Elsevier BV. ; , s. 215-220
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Konferensbidrag (refereegranskat)abstract
- A semiconductor hybrid pixel detector for dynamic X-ray imaging is developed. The detector, called DIXI, consists of a semiconductor sensor mounted onto a readout chip. A detector module with a silicon sensor is currently being assembled with the use of anisotropic conductive film as interconnection between the sensor and the readout chip. The basic building block of the detector is in size and consists of 992 square pixel cells arranged in 31 columns and 32 rows. The pixels have a side of . The readout chip is capable of performing photon counting and has an externally adjustable threshold. The readout chip has been characterised by charge injection in the absence of a sensor. The threshold dispersion is measured to 365 e− for hole collection. Even if the chip was not originally designed for electron collection a threshold dispersion of 1650 e− has been achieved. Two counters are implemented in every single pixel cell and the threshold can be changed from one image to the next in order to select different parts of the X-ray spectrum.
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