JPS6127715B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radiation measuring device that measures the radiation dose in the vicinity of a radiation source such as a nuclear reactor.

Conventionally, this type of radiation measuring device has used a detector that utilizes an ionization phenomenon or a detector that utilizes scintillation, but in either case, the detector can be considered to be a current pulse source. Figure 1 is
1 is a block diagram showing an example of a conventional radiation measurement device that measures a γ-ray energy spectrum using a Ge (Li) detector; in the figure, 1 is a high-voltage power supply;
is a Ge (Li) detector, 3 is a preamplifier, 4 is a main amplifier, and 5 is a pulse height analyzer.

Next, the operation will be explained. A strong electric field is generated in the detector 2 by the high-voltage power supply 1, and the electron-hole pairs generated by the radiation within the detector 2 are separated so that the amount of generated charge can be measured. Preamplifier 3 converts the current pulses from detector 2 into voltage pulses proportional to the current or charge. The main amplifier 4 is for amplifying the weak output voltage of the preamplifier 3 to several volts, and also incorporates a waveform shaping circuit, a polarity switching circuit, and the like. The pulse height analyzer 5 is a device for analyzing information converted into pulse heights.

Conventional radiation measurement devices are configured as described above, requiring a strong electric field to be applied to the detector, requiring a high-voltage power supply, and requiring electronic circuits such as amplifiers to be installed near the detector. . This becomes a major problem in measurement environments where radiation and strong electromagnetic fields coexist. Another drawback is that a large number of measuring devices must be installed when the measurement range is wide.

This invention was made to compensate for the drawbacks of the conventional methods as described above, and it is possible to measure the radiation dose from a long distance of the object to be measured, and to eliminate electromagnetic induction noise from a wide range of radiation in a measurement system where measurement accuracy is not a big problem. The aim is to provide a radiation measuring device that can measure radiation without being affected.

FIG. 2 is a block diagram showing an embodiment of the present invention. In the figure, 6 is an optical transmitter, 7 is an optical distributor with equal distribution ratios, and 8 is a connection between the optical transmitter 6 and the optical distributor 7. 9 is an optical fiber cable, 9 is a sensor section consisting of a plurality of optical fibers each containing different percentages of impurities such as Ge and P in the core material, 10 is a radiation source, and 11a, 11b, . . . are optical receivers and sensors, respectively. The optical signal from each optical fiber of section 9 is converted into a voltage signal. 12 is a pulse generator and pulse height analyzer.

Next, the operation will be explained. The optical transmitter 6 converts the voltage pulses outputted from the pulse generator/pulse height analyzer 12 into optical pulses and sends them to the optical fiber cable 8 . The optical distributor 7 equally distributes the optical signal input from the optical fiber cable 8 to each of the plurality of optical fibers of the sensor section 9. The sensor section 9 is disposed around the radiation source 10, and the core materials of the respective optical fibers of the sensor section 9 have different impurity contamination rates, and when irradiated with radiation, the optical signals passing through the respective optical fibers are different. are designed to have different attenuation amounts. The optical pulse signal attenuated in a certain functional relationship with the radiation dose is input to optical receivers 11a, 11b..., where it is converted into a voltage waveform signal and sent to the pulse generator/pulse height analyzer 12. . The waveforms of the input and output pulses are compared in the pulse generator/pulse height analyzer 12 to determine the radiation dose. In this measurement system, the length of the optical fiber of the sensor section 9 can be adjusted according to the measurement range, and can be used as a sensor for the total irradiation amount.

As described above, the present invention has the advantage that radiation can be measured from a distance without being affected by electromagnetic induction noise, and that the total amount of radiation irradiated over a wide range can be determined using a set of measuring devices.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a conventional radiation measurement apparatus that measures a γ-ray energy spectrum using a Ge(Li) detector, and FIG. 2 is a block diagram showing an embodiment of the present invention. In the figure, 6 is an optical transmitter, 7 is an optical distributor, 8 is an optical fiber cable, 9 is a sensor section, 10 is a radiation source, 11a, 11b, . . . are optical receivers, 1
2 is a pulse generator and pulse height analyzer.

Claims (1)

[Claims] 1 A plurality of optical fibers in which impurities such as germanium and phosphorus are mixed into the core material at different impurity mixing rates, and the optical signal passing through it is attenuated in accordance with the irradiated radiation and as a function of the impurity mixing rate. and an optical signal transmitter configured to equally supply the optical signal emitted from one optical transmitter to each of the plurality of optical fibers by an optical distributor having an equal distribution ratio. means, an optical signal receiving means configured to use separate optical receivers to receive the optical signals that have passed through each of the plurality of optical fibers, and a transmitted optical signal and a received optical signal. Therefore, a radiation measuring device comprising means for detecting attenuation of an optical signal in each of the plurality of optical fibers.