Analysis The Photon Counting Detector’s Performance And Research Its Circuit

Photon counting technique was first used in low light detection. Throughamplification, screening and processing of the weak signal, realize the detection of thevery weak incident photon.These applications demand led to the birth anddevelopment of photon counting technology. Photon counting technology as a newgeneration of X-ray imaging technology, combined with nuclear medicine detectiontechnology, detection technology, application-specific integrated circuit technology,the advanced semiconductor packaging technology field and experience of thesubjects. Especially for dose sensitive imaging field, such as breast imaging, thistechnique has a broad application prospect.So learn and master the technology, cangreatly reduce the incident X-ray dose, thereby reducing the radiation damage ofX-ray on the patient but at the same time guarantee the imaging effect. Many of thescientists agreed that the photon counting detectors will be the trend of the futuredevelopment of X-ray imaging. At present, China is still in the primary stage of X-rayphoton counting detector application and commercialization, and the development isrelatively slow.In further research based on XRI-UNO module, on the basis of photon countingdetectors, this paper puts forward a photon counting detector circuit design andimplementation method.The circuit consists of charge sensitive amplifier circuit,gaussian plastic amplification circuit, comparator circuit and pulse counting circuitbased on FPGA.Charge sensitive amplifier circuit through the integral action toconvert the input current signal to voltage signal;The gaussian shaping circuit byfiltering the input signal into gaussian waveform for subsequentprocessing;High-speed comparator and the use of ADI company AD8564, the inputgaussian signal conversion ChengFangBo output and maintain a CMOS/TTL-compatible;Counting circuit selects EP3C40chip of Altera company, can be used toinput the square wave counts and through the output displayed on the PC software.Through continuous exposure experiments on16channel tellurium cadmiumzinc design in this paper a lot of tests on the photon counting circuit, experimentsshow that the circuit has good energy resolution and higher ability to count, littleinterference between each channel.At the same time, the indicators such as sensitivity also achieved the desired design requirements.Meet the requirements of the small Xray testing instrument, the design method of follow-up study higher index of thedetector is of great significance.