| 摘要 |
PURPOSE:To provide a radiation detection instrument having a good directivity and a high detection sensitivity, by providing a plurality of grooves in arrays on one surface of a semiconductor substrate, providing semiconductor layers having the opposite type of conductivity to that of the substrate along the grooves and further providing signal electrodes on the surfaces of the grooves and a common electrode on the other surface of the semiconductor substrate. CONSTITUTION:When a semiconductor substrate 1 is of CdTe (p-type semiconductor), it is first provided with grooves 11 in arrays and aluminium is vapor deposited on the recessed surface of each of the grooves 11. The aluminium is thereby penetrated into the CdTe and combined therewith to form an N-type semiconductor layer 12. In other words, a p-n junction is formed there. A signal electrode 13 formed of aluminium for example is provided on the surface of each groove 11. An internal electric field is produced in the p-n junction (depletion layer M), and when radioactive rays are applied thereto, pairs of electrons (e) and holes (h) are produced in accordance with the intensity of the radioactive rays, in the CdTe semiconductor which the radioactive rays have passed through. the electron (e) and hole (h) pairs produced in the section of the depletion layer M are caused to flow by the electric field in the depletion layer. Thus, a radiation detection instrument according to the invention has a directivity sensitive only to radioactive rays applied in the direction (A) approximately vertical to the groove 11.
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