| 摘要 |
The detector is formed by a honeycomb collimator 1 in which the ratio of the diameter of the hexagons to the thickness is of the order of 1/4. Behind this is situated a scintillator crystal 2, made for example of thallium-doped sodium iodide. This crystal is inspected by objectives 4 with a very high numerical aperture. These objectives form an image of the crystal on CCDs 6 cooled to - 40 DEG C. The whole is protected by a shielded case 5. <IMAGE>
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