A High Position Resolution X-ray Detector: an Edge on Illuminated Capillary Plate Combined with a Gas Amplification Structure

摘要

We have developed and successfully tested a prototype of a new type of highposition resolution hybrid X-ray detector. It contains a thin wall lead glasscapillary plate converter of X-rays combined with a microgap parallel-plateavalanche chamber filled with gas at 1 atm. The operation of these converterswas studied in a wide range of X-ray energies (from 6 to 60 keV) at incidentangles varying from 0-90 degree. The detection efficiency, depending on thegeometry, photon energy, incident angle and the mode of operation, was between5-30 percent in a single step mode and up to 50 percent in a multi-layeredcombination. Depending on the capillary geometry, the position resolutionachieved was between 0.050-0.250 mm in digital form and was practicallyindependent of the photon energy or gas mixture. The usual lead glass capillaryplates operated without noticeable charging up effects at counting rates of 50Hz/mm2, and hydrogen treated capillaries up to 10E5 Hz/mm2. The developeddetector may open new possibilities for medical imaging, for example inmammography, portal imaging, radiography (including security devices),crystallography and many other applications.