| 摘要 |
PURPOSE:To reduce the weight of a radiation detector and to improve the defection efficiency thereof by providing 1st and 2nd radiation detecting means maintaining a certain distance therebetween on a course where radiations pass and outputting only the signal by the radiations simultaneously detected by both the detecting means. CONSTITUTION:The radiations entering at the angles of the radiations b, c with respect to a center line 20 pass only one of the 1st and 2nd radiation detecting means when 3 ways of the incident radiations (a), (b), (c) are considered. The signal from the detecting means is, therefore, outputted only from one detection means. The angle between the course of the radiations and the center line 20 is small on the contrary and the radiation (a) parallel or nearly parallel with the detecting means pass both the radiation detecting means and the signal is outputted from both. Only the radiations within a certain range can, therefore, be detected if only the signal to cause scintillators 13a, 13b to emit light simultaneously is detected. Since the need for a collimator using lead is eliminated by this detector, the reduction of the weight is permitted and since the detector itself has a collimating effect the detector can be brought near to a measuring object. The detection sensitivity is thus improved.
|
