Fabrication and Characteristics of a Submillimeter Detector Element Formed on a CdTe Single-Crystal Wafer as a Multichannel Detector Array Applicable to Diagnostic Imaging with Energy Information

A feasibility study to realize a minimal-sized X-ray detector element applicable to a multichannel array for diagnostic imaging with energy information is attempted. A thirty-two-channel radiation detector is fabricated by arranging thirty-two detector elements, each having an effective detection volume of 1× 0.25× 0.3 mm³ with a pitch of 0.25 mm, on a CdTe single-crystal wafer measuring 1(width)× 8(length)× 0.3(thickness) mm³. Thirty-two divided electrodes are arranged on its surface, and a common electrode is provided on its rear surface. A radiation spectrum measurement conducted at room temperature for one of the elements with ²⁴¹Am γ-ray (59.54 keV) shows an energy resolution of 12% full width at half maximum (FWHM). Furthermore, by providing radiation shielding grids between electrodes, a reduction of K-shell characteristic X-ray escape from 40% to 30%, as well as a resultant reduction in channel crosstalk against the total counts, is accomplished.