JPH03183985A - Radiation measuring and analyzing device - Google Patents

Abstract

PURPOSE:To take a fission analysis immediately at a measurement site by one device by providing a radiation detector, an A/D converter, a memory stored with a digital signal, an arithmetic circuit which counts an integration increment at specific intervals of time, and a display device. CONSTITUTION:The radiation detector 10 detects, for example, alpha rays and outputs a detection signal 10a corresponding to the energy of the alpha rays. This signal 10a is amplitude-amplified by a preamplifier 12 and passed through an A/D converter 14 to convert a signal larger than a specific crest value level into a digital signal. Then the digital signal is stored in a memory 16 in real time as a multichannel wave height analyzer (MCA) function. Then the storage contents stored in the arithmetic circuit 18 are integrated for a specific time within the energy range of a specific area. Further, the integral increment of the digital signal integrated by the circuit 18 is counted and the counted value is displayed on a display device 22 through a display controller 20.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a radiation measurement and analysis device, and particularly to a radiation measurement and analysis device that detects a predetermined radioactivity concentration using a radiation detector and displays the radiation count value and counting rate. The present invention also relates to a radiation measurement and analysis device that displays the energy distribution of radiation determined by a pulse height analyzer.

[Prior art] Radiation monitors such as survey meters are well-known as measuring instruments for detecting radiation in facilities such as laboratories that handle radioactive isotopes, and nuclear facilities such as nuclear power plants, nuclear fuel material handling facilities, and reprocessing plants. be.

This type of radiation measuring instrument counts pulse signals corresponding to radioactivity concentration and dose equivalent, displays the counted value on a rate meter, and monitors radioactive contamination.

In particular, since the purpose of survey meters is to measure the distribution of dose equivalent rate and radioactivity surface density within a facility, they are designed to be small and portable for convenient portability.

It is extremely important for radiation management to use this survey meter to measure the distribution of dose equivalent rates and radioactivity surface density in facilities handling radioactive materials.

The types of survey meters can be broadly classified into various types using detectors such as scintillation detectors, semiconductor detectors, and proportional counters, and the measured values are displayed using a dose equivalent rate meter or a count rate meter, respectively.

On the other hand, pulse height analyzers that express the number of pulses of a pulse signal output from a radiation detector as a count value or as an energy distribution are widely used.

This pulse height analyzer is a measuring instrument used in radiation nuclide analysis to determine the energy distribution of radiation. Since the pulse height value is proportional to the absorbed energy, the absorbed energy distribution can be determined by analyzing the pulse height value.
In conventional radiation analysis, such a pulse height analyzer has become indispensable.

This type of pulse height analyzer is generally constructed by combining two pulse height discrimination circuits and a reverse counting circuit. It works to prevent pulses from passing through.

Then, when the output pulse is input to the reverse counting circuit, the two different pulse height discrimination voltages of the upper limit and lower limit levels are set by the two wave height discrimination circuits, so that the pulse height discrimination of the upper limit and lower limit levels is performed. Only the peak value pulses that fall within the voltage difference ΔV are selected and counted.

This ΔV is called the channel width, and a single channel pulse height analyzer (SCA) fixes this channel width ΔV, sequentially moves the lower limit level voltage V, and outputs the counting rate to a recorder each time. , radiation energy distribution can be obtained.

Since such a single channel pulse height analyzer has a single channel width ΔV, it is necessary to constantly vary the level voltage V to an optimum value according to the pulse height value of the input pulse. However, on the other hand, a plurality of channel widths ΔV
By setting , there is no need to move the level voltage V, and the input pulse can always be input into the channel width ΔV. This is a multichannel pulse height analyzer (MC
A), which has the advantage of being able to measure with higher precision and in a shorter time than the SCA. This MCA uses an A/D conversion method that converts pulse peak values into digital values.

The multi-channel pulse height analyzer with the above features uses a radiation detector and counts the output pulse signals to obtain the energy distribution of the detected radiation, thereby identifying nuclides, etc. It is widely used because it can be analyzed all at once.

As mentioned above, both a survey meter and an MCA are required for radiation measurement and nuclide analysis.
Radiation detection and energy analysis are performed using various types of equipment.

That is, for example, a measurer brings a survey meter to the measurement site and searches for the location where the radioactivity concentration is highest. Then, take this sample home and measure it in another location, such as an indoor measurement room, and finally display the energy distribution.
Nuclide analysis is being conducted.

In this way, in conventional radiation measurement and nuclide analysis, it was necessary to perform radiation measurement with a survey meter and nuclide analysis with MCA in two separate steps.

This is because compared to survey meters, which are smaller and more portable, MCAs have traditionally been made for the purpose of measuring samples in measurement rooms, and the equipment itself has also been larger. .

Therefore, in conventional radiation analysis, measurements and analyzes were usually performed at different locations using two different types of equipment.

[Problems to be Solved by the Invention] As described above, in conventional radiation analysis, two measuring devices, a survey meter and an MCA, must be provided separately and independently, and the survey meter must be equipped with two measuring devices, a survey meter and an MCA. (radioactivity concentration) and then taking the sample back to the measurement room for nuclide analysis using MCA, which took time and effort.

For this reason, for example, if a high concentration of radioactive material is discovered, it is necessary to conduct nuclide analysis as soon as possible and take appropriate improvement measures based on the analysis results. Radiation measurements were taken at the site, and samples were then taken home and analyzed using MCA in the measurement room, which inevitably took time.

Therefore, it has not been possible to detect radiation at the measurement site and to immediately perform nuclide analysis of the radiation on the spot.

Purpose of the Invention The present invention has been made in view of the above-mentioned conventional problems,
The purpose is to provide a radiation measurement and analysis device that includes a survey function and a wave height analysis function, and thereby enables immediate nuclide analysis of radiation at the measurement site with a single device.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a radiation detector that detects predetermined radiation and outputs a detection signal corresponding to the energy of the radiation; A/
A D converter, a memory that stores the digital signal, an arithmetic circuit that integrates the contents stored in the memory in an arbitrary energy range and counts the cumulative increase at predetermined intervals, and calculates radiation from the counting result. The present invention is characterized in that it has a display that displays the count value, count rate, and energy distribution, and is capable of detecting a predetermined radioactivity concentration and analyzing the nuclide of the radiation.

[Function] With the above configuration, according to the measurement and analysis device according to the present invention, a predetermined radiation is detected by the radiation detector at the measurement site, and a detection signal corresponding to the energy of the radiation is obtained. . Then, this detection signal is A/
A D converter converts the signal of the detector number above a predetermined peak value level into a digital signal and stores it in a memory.

Furthermore, the content stored by the arithmetic circuit is integrated over a given energy range, the integrated increase is counted at predetermined intervals, and the counted value, counting rate, and radiation energy distribution are displayed on the display from the counting results. can be displayed.

As a result, along with the detection of radioactivity, which is a survey function,
The energy distribution display enables nuclide analysis, allowing rapid on-site radiation measurements and nuclide analysis.

[Embodiments] Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 1 is a block diagram showing the main circuit configuration of a radiation measurement and analysis device according to the present invention.

A feature of the present invention is that it is possible to detect a predetermined radiation and to analyze the nuclide of the radiation using a single measurement and analysis device equipped with a survey function and a wave height analysis function.

An example of the circuit configuration will be described below using the embodiment shown in FIG.

In the figure, a radiation detector 10 is a sensor that detects predetermined radiation, such as α rays, β rays, γ rays, etc., and outputs a detection signal 10a corresponding to the energy of the detected radiation to a preamplifier 12, The detection signal is amplified to a predetermined amplitude level.

Among the amplified detection signals, the signals having a predetermined peak value level or higher are converted into digital signals by the A/D converter 14, and this converter is composed of, for example, a plurality of comparators.

The converted digital signal is stored and accumulated in a memory 16 which is a storage section, and this memory 16 is composed of, for example, a plurality of IC memories (RAM), magnetic memories, and the like.

The above-mentioned stored contents are integrated in a predetermined energy range by the arithmetic circuit 18, and the integrated increase is counted every predetermined time.

That is, this arithmetic circuit 18 constantly monitors how many digital signals are stored in the memory 16.

The count value of the arithmetic circuit 18 is converted into an analog signal for displaying an image, for example, by a display controller 20,
The display controller 2o outputs a display signal 20a. Further, this display controller 20 can also directly input the contents of the memory 16, convert it into an analog signal, and display the image.

The display signal 2a from the display controller 20 is input to the display 22, and the display 22 is for displaying the radiation count and radiation energy distribution from the counting results, for example. Such as a television monitor.

Next, the operation of the main circuit configuration shown in FIG. 1 will be explained below using FIG. 2.

FIG. 2 shows a state in which the count value and energy distribution of radiation are displayed as an image 22b on the display 22.

That is, in this Figure 2, the energy level E (e
V), the vertical axis shows the count value, and the upper left of the display shows the count rate of the entire energy distribution 20b, for example, TOTAL1
23 cpS is shown, and in the upper right of the display, an arbitrary energy range of the energy distribution, for example, a portion 20c of the diagonal line is shown.
The count rate of ROI 1.2 c p s is shown.

In FIG. 1, first, as a survey function, the radiation detector 10 detects α rays using, for example, an α ray sensor, and α
A detection signal 10a corresponding to the energy of the line is output.

The amplitude of this detection signal 10a is amplified by a preamplifier 12, and further, a signal having a predetermined peak value level or higher among the detection signals is converted into a digital signal via an A/D converter 14.

In this way, the measurement of radiation as a survey meter, for example the presence of alpha radiation, is detected. However, in the process up to this point, the energy distribution of the radiation is unknown and nuclide analysis is not possible, so the next MCA function first stores the digital signal in the memory 16 in real time.

1 Then, the arithmetic circuit 18 integrates the stored contents over a predetermined energy range for a predetermined period of time.

Here, the sampling period for capturing the detection signal (data) is, for example, 30 seconds when the radiation is relatively weak.
Alternatively, if the radiation is relatively strong, the time period is set to 3 seconds, for example, and measurement is performed according to the number of detected data.

Therefore, in some cases, for example, when the radiation is extremely weak, it takes about 5 to 10 minutes to measure in order to obtain an energy distribution display.

Further, the arithmetic circuit 18 counts the cumulative increment of the digital signal accumulated at predetermined intervals as described above, and displays this counted value on the display 22 via the display controller 20. As a result, energy information as shown in FIG. 2 can be obtained, for example.

As a result, in the radiation energy distribution shown in FIG. 2, one peak value with a large count value is obtained in a relatively low energy region, while two peak values with a large count value are obtained in a high energy region. value is obtained.

According to the circuit configuration of this embodiment, as shown in FIG. 2, by selecting the TOTAL counting rate 20b and any region of the displayed energy range, for example, the ROI counting rate (hatched area) 20c. It becomes possible to obtain. Therefore, the nuclide can be analyzed based on the presence or absence of these peak values.

That is, if radioactive materials are present at the measurement site, e.g.
If cesium, cobalt, etc. are present, for example, a relatively large peak value of the count value can be confirmed in a specific energy region. This allows for specific nuclide analysis.

As described above, by using the device of this embodiment, the measurer can observe the count values and energy distribution display shown in Figure 2 while performing measurements at the measurement site, which was previously impossible with a single device. Radiation detection and nuclide analysis will become possible.

Next, FIG. 3 shows a front view of a specific portable radiation measurement and analysis device according to the present invention.

That is, this measurement and analysis device 1-00, which has both a survey function and a wave height analysis function, has an operation panel 110 and a display section 120 that displays images of counted values and energy distribution on the front of its housing. Further, as described above, the radiation detector 10 is configured to be connectable as shown in the figure.

Further, to enable portability, a carrying handle 130 is provided on the top surface of the measurement and analysis device main body 100, as shown in FIG. 3, and shoulder belts 40 are provided on the left and right sides. ing.

In addition, in the apparatus of this embodiment, for example, the radiation detector 10 may be built into the back of the apparatus main body 100, or may have a structure in which it can be stored, or a structure in which it can be connected with a connector, a cable, or the like.

[Effects of the Invention] As explained above, according to the radiation A111 constant analysis device according to the present invention, since one device is equipped with a survey function and a wave height analysis function, radiation can be measured immediately at the measurement site. At the same time, it becomes possible to easily perform nuclide analysis.

5. Also, since it becomes possible to quickly devise appropriate countermeasures from the analysis results, it has the effect of improving safety in radiation management.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the circuit configuration of the radiation measurement and analysis device according to the present invention, Fig. 2 is an explanatory diagram showing the image display of count values and energy distribution by the analysis device, and Fig. 3 is FIG. 1 is a schematic configuration diagram of a radiation measurement and analysis device according to the present invention. 10...Radiation detector 10a...Detection signal 12...Preamplifier 14...A/D converter 16...Memory 18...Arithmetic circuit 20...Display controller 20a... Display signal 22...Display device 6

Claims (1)

[Scope of Claims] A radiation detector that detects a predetermined radiation and outputs a detection signal corresponding to the energy of the radiation, and an A/D converter that converts a signal of a predetermined peak value level or higher among the detection signals into a digital signal. a D converter, a memory that stores the digital signal, an arithmetic circuit that integrates the contents stored in the memory over a given energy range and counts the cumulative increase at predetermined intervals; 1. A radiation measurement and analysis device comprising: a display device that displays a count value, a count rate, and an energy distribution;