PURPOSE: To achieve the wt. reduction of a radiation detector, to enhance directionality and to realize the improvement of scanning properties and the detailedness of detection data.
CONSTITUTION: A detection part is constituted of a Phoswich detector 1 consisting of a plastic scintillator 1a and a CsI(T1) scintillator 1b and γ-rays are incident to those scintillators to emit light pulses which are, in turn, converted to electric signals by a photoelectric converter 1c. These electrical pulses are shaped and amplified by a preamplifier 5 and a linear amplifier 6 and the timings at two arbitrary points are detected at the rising parts of the pulses different in attenuation time by a constant fraction system. The time lag between two points is inputted to a rise time to height converter 7 converting said time lag to wave height to output the same and the scintillation pulse of the plastic scintillator is triggered to measure the scintillation output of the CsI(T1) scintillator. That is, incident γ-rays are detected only when both of two scintillators emit light.
HAYASHIZU TAKEATSU
OGATA YOSHIKI
MITSUBISHI HEAVY IND LTD