| 摘要 |
PROBLEM TO BE SOLVED: To obtain a detector improved in sensitivity in which a distance between a radiation-detecting part and a signal-processing part can be extended by setting a wavelength conversion fiber to reciprocate in a longitudinal direction of a scintillator and collecting the light emitted in the wavelength conversion fiber by a transmission optical fiber. SOLUTION: The fiber optic radiation detector consists of a transmission optical fiber 8 connecting a detecting part 20 and a signal-processing part 21. A columnar thallium-activated sodium iodide crystal is used as a scintillator 2 and a wavelength conversion fiber 3 is used as a light-transmitting member including a fluorescent substance. One wavelength conversion fiber is set to a circular position centering a center axis of the scintillator 2 to reciprocate three times in a longitudinal direction of the scintillator. A photoelectron conversion element 9 outputs a signal of one pulse per one radiation applying an energy to the NaT (T1) crystal. A pulse voltage is proportional to the number of photons of a wavelength-converted light 42 transmitted to the photoelectron conversion element 9. A preamplifier 10 and an amplifier 11 amplify signals and a pulse height discriminator 12 extracts signals of a constant range so as to reduce mainly electric noises.
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