| 摘要 |
<p>In a radiation distance detection device (2) with an optical fibre (4) coupled to an inorganic detector crystal (10), the crystal is surrounded by, and in optical contact with, an optical cladding (12) of refractive index less than that of the crystal, so that light is confined by total reflection at the crystal/cladding interface. Pref. the cladding (12) consists of silica, silica-based glass, organic glass, fluoride glass, chalcogenide glass or polymeric material. The detector crystal (10) may be made of: (a) a scintillating inorganic material selected from bismuth germanate, sodium iodide, calcium tungstate, cadmium tungstate, caesium fluoride, calcium fluoride and lithium iodide; or (b) an optically stimulable luminescent inorganic material such as doped sulphides, doped silica, doped oxides (e.g. doped germanium oxide), doped optical glasses and doped fluoride glasses, the dopant being a rare earth. Pref. the refractive indices of the crystal (10) and the cladding (12) are chosen such that the numerical aperture of the clad crystal is slightly less than that of the optical fibre (4). <IMAGE></p> |
