KR101962360B1 - A method for detecting a radionuclide, a process for detecting a radionuclide using the same, and a radiation detecting devece for the same - Google Patents

Abstract

The present invention relates to a method for detecting a radionuclide by using energy spectrum data represented by counts depending on energy obtained from a radiation detector, including calculating a count ratio by dividing object energy spectrum data by background energy spectrum data with respect to any energy value by using the object energy spectrum data measured in the presence of the object and the background energy spectrum data measured without the object of radionuclide detection. When the radionuclide detection method according to the present invention is employed, a nuclide can be very effectively discriminated even at a small radiation from the actual object by means of the introduction of a new discriminant and a new algorithm. According to the present invention, it is not necessary to introduce a new device or a component into an existing system and the present invention can be applied once the new discriminant and the new algorithm presented by the present invention are introduced into the existing system. Accordingly, compatibility can be maximized with existing radiation detection systems. In addition, the detection method allows easy radionuclide detection, and thus the present invention can be used for a variety of objects such as cargoes, radiation wastes, and foods.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a method for detecting a radionuclide, a radionuclide detecting process using the same, and a radiation detecting apparatus for the same.

The present invention relates to a method for detecting a radionuclide, a radionuclide detecting process using the detecting method, and a radiation detecting apparatus therefor.

Radiation measurements that measure radiation from an object are widely used in a variety of fields such as nuclear power facilities and medical facilities, as well as cargo entering and exiting airports and ports. As an example, Korean Patent No. 1581004 ("Exit Vehicle Radiation Monitoring System ", hereinafter referred to as prior art 1) discloses a technique for checking the presence or absence of radiation of a vehicle installed in a doorway and passing through the doorway. The system disclosed in the prior art document 1 includes a plastic scintillator for generating scintillation light when a light of a specific wavelength is received, thereby analyzing a scintillation signal generated in the scintillation object by radiation emitted from the object to measure the presence or absence of radiation.

A more detailed description of the scintillator is as follows. An inorganic scintillator, such as NaI (TL), can generate photons of a specific intensity proportional to the energy of the incident radiation to measure the energy of the incident radiation. Therefore, inorganic scintillators are mainly used for nuclide analysis based on energy and intensity of incident radiation. On the other hand, the organic scintillator such as PVT (Polyvinyltoluene) has a low density and it is difficult to measure the energy of the incident radiation because the probability of occurrence of interaction with the incident radiation due to the photoelectric effect is low. Therefore, the organic scintillator only measures the intensity of the incident radiation . However, plastic organic scintillators are widely used for measuring the presence or absence of radiation in cargo, because they are easier to manufacture than inorganic scintillators and can be manufactured in sizes larger than m ² . In the radiation measurement system of the above-mentioned prior art document 1, as described in the use of a plastic scintillator, that is, an organic scintillator, a cargo radiation detection system generally installed at an airport or a port entrance is a PVT plastic having a volume of 25 L to 65 L A scintillator is used.

However, in such a radiation detection system, not only the presence of radiation but also the presence or absence of artificial radiation, that is, the function of determining the nuclide of artificial radiation, is also required. As described above, if a radiation detector using an inorganic scintillator is used, the presence or absence of artificial radiation can be easily determined because the radiation energy and intensity can be measured and analyzed for nuclides. However, when a radiation detector using an organic scintillator is used, Since we mainly measure only the intensity of artificial radiation, we should distinguish between artificial radiation and natural radiation.

To date, natural radiation and artificial radiation have been classified into two categories: first, direct comparison of energy spectral data measured with plastic scintillation data to background spectral data; second, determination of weighted energy values of energy spectra measured with plastic scintillators; . The first method, that is, a method of directly comparing spectral data is disclosed in Korean Patent Laid-Open Publication No. 2016-0060208 ("Method and apparatus for separating radionuclides using plastic scintillators", hereinafter referred to as Prior Art 2) The method is disclosed in detail in Korean Patent Publication No. 2010-0033175 ("Plastic scintillation-based radiation detector and method for detecting radionuclides using the same, hereinafter referred to as Prior Art 3).

However, considering the vehicle speed (up to 18 km / h) and the length (up to 15 m) of the vehicle passing through the actual cargo radiation detection system, the vehicle passing time is within 3 seconds for short time and within 10 seconds for long time, The above two methods may be difficult to be practically used. Also, if there are several sources of radiation, it can be an environment that is more difficult to judge.

An object of the present invention is to provide a method for detecting a radionuclide, a method for detecting a radionuclide using the detection method, and a radiation detecting apparatus therefor.

In order to achieve the above object,

According to a first aspect of the present invention,

A method for detecting a radionuclide using energy spectrum data represented by a count according to an energy obtained from a radiation detector,

The background energy spectrum data measured without the object to detect the radionuclide and the object energy spectrum data measured in the presence of the object are used to divide the object energy spectrum data into arbitrary energy values into the background energy spectrum data and calculate the count ratio Calculating;

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A method for detecting radionuclides is provided.

In addition, the second aspect of the present invention,

In a radionuclide detection process using a radiation detector and a method for detecting a radionuclide according to the first aspect of the present invention,

An energy spectrum data measurement step of measuring background energy spectrum data in the absence of an object with the radiation detector and measuring object energy spectrum data in the presence of an object with a radiation detector;

And when the count of the object energy spectrum data is equal to or larger than the detection reference value, the count ratio calculating step is performed to detect the radionuclide species;

Containing

Thereby providing a radionuclide detection process.

The third aspect of the present invention,

A radiation detector for measuring background energy spectrum data in the absence of an object and measuring object energy spectrum data in the presence of the object;

A calculation unit for performing count ratio calculation for an arbitrary energy value using energy spectrum data represented by a count according to energy obtained from the radiation detector; And

A judging unit for discriminating the radionuclides by analyzing the count ratio;

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A radiation detection apparatus is provided.

When employing the method for detecting a radionuclide according to the present invention, a new discriminant and an algorithm can be introduced to easily and effectively discriminate the radionuclide even if the radiation from the actual object is not very large. Particularly, the present invention can be applied to a conventional apparatus by introducing only a new discrimination formula and algorithm proposed in the present invention without necessity of introducing a new apparatus or a part into an existing system, Can be maximized.

In addition, when the above-mentioned detection method is employed, radionuclides can be easily detected. Therefore, the present invention can be widely used as various objects such as cargo, radioactive waste, food, and the like.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a graph showing energy spectral data measured for various sources by a radiation detector using a plastic scintillator,
FIG. 2 is a graph showing a count ratio according to energy values for various sources,
3 is a schematic view showing a radionuclide detection step in the present invention,
4 is a block diagram schematically showing a radiation detection apparatus according to the present invention.

According to a first aspect of the present invention,

A method for detecting a radionuclide using energy spectrum data represented by a count according to an energy obtained from a radiation detector,

The background energy spectrum data measured without the object to detect the radionuclide and the object energy spectrum data measured in the presence of the object are used to divide the object energy spectrum data into arbitrary energy values into the background energy spectrum data and calculate the count ratio Calculating;

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A method for detecting radionuclides is provided.

Hereinafter, a method for detecting a radionuclide according to the first aspect of the present invention will be described in detail with reference to FIGS. 1 and 2. FIG.

First, in the present invention, the reason for detecting the radionuclide is defined as follows in order to distinguish between natural radiation and artificial radiation. It is well known that radiation below a certain level does not cause a significant adverse effect on the human body, and that such a degree of fine radiation is generally emitted to objects in the natural world. Such radiation is called natural radiation. On the other hand, artificial radioactive materials such as cesium (Cs-137) and cobalt (Co-60) emit more radioactive rays than natural radiation, and if this amount of radiation is increased, the human body may be adversely affected. In other words, radiation emitted from such artificial radioactive materials is called artificial radiation. Accordingly, the method of detecting the radionuclide of the present invention may be performed to detect artificial radiation harmful to the human body.

In addition, in comparison with the natural radiation measured in a state in which nothing is detected as a radionuclide (which is generally referred to as a "background state"), radiation which can be presumed to be radiation generated in a specific radioactive material, . Therefore, in order to detect radionuclides, it is the most fundamental step to obtain energy spectrum data using a radiation detector.

Meanwhile, the method of detecting a radionuclide of the present invention is not introducing a new apparatus or a component but introducing a new discriminant equation and algorithm, while using the existing radiation detector and detection system as it is. From this viewpoint, in the present invention, the method of obtaining the energy spectrum data by the radiation detector itself or the radiation detector is the same as the conventional method, so that the description thereof will be briefly described.

A method of obtaining energy spectrum data from a radiation detector will be briefly described as follows. For example, when the radiation detector is a radiation detector using a plastic scintillator, if a plastic scintillator is irradiated with radiation from an object, a scintillation signal is generated in the plastic scintillation material. It transforms the flash signal into an electrical signal, amplifies its size, and removes noise to convert it into an analytical signal. The converted signal appears as a pulse, which is counted and stored according to the magnitude of the voltage value. Each process in which the pulses of the respective voltage values are counted and cumulatively managed in the allocated buffer for a predetermined time is referred to as energy. Through this process, the energy spectrum data represented by the count value according to the energy value can be obtained. As described above, the radiation detector using the plastic scintillator finds the energy spectrum data in this manner (the energy spectrum graph obtained by this method is disclosed in all of the above-mentioned prior art documents 1 to 3), and further detailed explanation is omitted do.

This energy spectral data depends on the nuclide of the material that is the source (source) that generates the radiation. Therefore, ideally, if you know in advance what type of energy spectral data is coming from a nuclide in advance, you will be able to determine the nuclide of the source contained in the object from the measured energy spectral data.

However, as shown in FIG. 1, when energy spectrum data based on energy are distinguished only from each other, energy spectrum data according to each radionuclide are superimposed on each other, so that discrimination thereof is not easy.

Therefore, the present invention intends to easily detect radionuclides by introducing new discriminants and algorithms as described below.

In the method for detecting the radionuclide, the background energy spectrum data measured without the object to detect radionuclides and the object energy spectrum data measured in the presence of the object are used to calculate the object energy spectrum The data is divided into background energy spectrum data to calculate a count ratio.

At this time, the count ratio is defined as a value obtained by dividing the object energy spectrum data by background energy spectrum data with respect to an arbitrary energy value, and the count ratio of the background energy spectrum data becomes 1 regardless of the energy value.

2 is a graph showing a count ratio according to energy values for various sources. Referring to the graph, it can be seen that peaks of each radionuclide have different peaks. As compared with FIG. 1, it can be seen that each radionuclide is easily distinguished from each other.

In addition, the kind of the radiation detector may be a detector using a gas ionization action, a detector using a solid ionization action (semiconductor detector), or a detector using an excitation action, and preferably a detector using an excitation action.

The detector using the gas ionizing action may be, but is not limited to, an ionizer, a proportional counter, a quenching gas, or a Geiger Muller counter.

The solid ionization detector (semiconductor detector) may be, but is not limited to, a P-N junction detector, a surface barrier detector, a Li drift type (p-i-n type detector) or a high purity semiconductor detector.

In addition, the detector using the excitation function emits light of a proper wavelength when a certain atomic substance in the scintillator is irradiated, and when the atom or molecule of the substance returns to a base-excited state, Lusite) pipe, the Sb-Sc is changed from the front surface of the deposited light to the electron and amplified by a dynode to obtain an electric signal. The scintillator is an inorganic crystal type, an organic crystal type, a liquid type , Or plastic, but is not limited thereto.

The method for detecting the radionuclide may further include discriminating the radionuclide detected from the object by comparing the count ratio with a previously prepared radionuclide count ratio.

At this time, the comparison may be to find and compare a minimum energy value within a certain range of the count ratio. The predetermined range may be about 1.1 times to about 1.2 times as much as one reference, but is not limited thereto. Preferably, the step of finding an energy value having the count ratio equal to 1 may be included. That is, referring to FIG. 2, the count ratio of the background energy spectrum data is 1 regardless of the energy value, and the count ratio of all the radionuclides converges to 1 as the energy increases. At this time, since the minimum energy value at which the count ratio converges to 1 differs depending on the type of radionuclide, the radionuclide may be detected by finding a minimum energy value within a certain range of the count ratio.

Further, in a specific radionuclide, the minimum energy value within a certain range from 1 and the minimum energy value within a certain range of the specific radionuclide prepared in advance may not always appear to be the same value. And the minimum energy value within a certain range, it is judged to be the same radionuclide if the error is within about 20%.

Meanwhile, the energy value of the radionuclide species prepared in advance means the value of energy stored in the radionuclide according to the first aspect of the present invention.

On the other hand, the comparison may be to find and compare an energy value having the maximum count value. That is, referring to FIG. 2, it can be seen that the energy representing the maximum count ratio is different for each type of radionuclide, and therefore, the energy value having the maximum count value is found and compared with the previously prepared radionuclide type count ratio May be to detect radionuclides. At this time, in the specific radionuclide, the energy value representing the maximum count ratio and the energy value representing the maximum count ratio of the specific radionuclide prepared in advance may not appear to be the same value, and the energy representing the maximum count ratio of the prepared radionuclide And if it is within an error range of about 20%, it is judged to be the same radionuclide.

Also, the comparison may be to compare the pattern of the count ratio with energy. That is, referring to FIG. 2, the patterns of the count ratios according to energy are different for each kind of radionuclide, and it may be possible to detect radionuclides by searching for the same pattern by comparing with the pattern of the count ratio of prepared radionuclides .

Also, the step of performing the count ratio calculation may be performed while changing the energy value, and the count ratio may be defined within a predetermined arbitrary energy period, i.e., a predetermined lower energy value to an upper energy value have.

At this time, the lower limit energy value may be generally determined as 0 or 1. [ The energy value corresponds to an index as a discrete value. At this time, in general, when the index numbering is started from 0 or starting from 1 is widely used, if the index numbering starts from 0, the lower limit energy value can be 0, and if the index numbering is 1 The lower limit energy value may be 1.

Also, the upper limit energy value may be determined as the highest one of the actual energy values, but not limited thereto, and may be determined as an appropriate energy value.

That is, referring to FIG. 2, after calculating the count ratio using the background energy spectrum data and the object energy spectrum data, if the count ratio of the energy is represented on one graph, the count ratio of each radionuclide It is easy to distinguish them. Therefore, it may be possible to detect the radionuclide by comparing the count ratio according to the energy with a previously prepared radionuclide species count ratio. As described above, the comparison is performed by finding and comparing a minimum energy value having a count ratio within a range of 1, searching for and comparing an energy value having a maximum count value, or comparing the pattern of the count ratio with energy Or may be to use them in combination.

In addition, the second aspect of the present invention,

In a radionuclide detection process using a radiation detector and a method for detecting a radionuclide according to the first aspect of the present invention,

An energy spectrum data measurement step of measuring background energy spectrum data in the absence of an object with the radiation detector and measuring object energy spectrum data in the presence of an object with a radiation detector;

And when the count of the object energy spectrum data is equal to or larger than the detection reference value, the count ratio calculating step is performed to detect the radionuclide species;

Containing

Thereby providing a radionuclide detection process.

The second aspect of the present invention utilizes the method of detecting the radionuclide of the first aspect of the present invention, and the above process is shown in FIG. A second aspect of the present invention is a method for measuring background energy spectral data in the absence of an object with a radiation detector before performing the method of detecting the radionuclide and measuring the energy spectrum of the object energy spectrum data in the presence of the object with the radiation detector Data is measured.

Thereafter, if the count of the object energy spectrum data is equal to or greater than the detection reference value, a method for detecting the radionuclide of the first aspect of the present application is performed in the second aspect of the present invention to detect the radionuclide.

At this time, the detection reference value may be determined to be about 1.2. That is, when the count of the object energy spectrum relative to the count of the background spectrum data is 1.2 times or more, it is judged that the object is at a level suspected of containing the artificial radioactive material. The detection reference value 1.2 is increased by 20% or more as compared with the background count, and the detection reference value can be changed by an institution or a person who operates the apparatus.

For example, assuming that 10,000 counts are in the background, if the count reaches 11,500 with the object entering, this object emits radiation at the natural radiation level and is considered safe. In this case, that is, if the count of the background spectral data and the count of the object measurement spectral data is less than the detection reference value, it is determined that the object does not contain the radioactive material and the object is passed through.

On the other hand, assuming that the count value is 10,000 in the background state, if the count value reaches 12,500 when the object enters, the object emits radiation above the natural radiation level, It is judged that it is necessary to inspect it.

Whether or not the object contains an artificial radioactive material can be judged through the method of detecting the radionuclide of the first aspect of the present invention. That is, if the count of the object spectral data of the background spectral data is greater than or equal to the detection reference value, the detection method of the radionuclide on the first side is performed, thereby detecting the radionuclide and checking whether the object contains the artificial radioactive material .

If it is determined that there is no artificial radiation in the object in the radionuclide detection step, it is determined that the object emits radiation of a relatively strong intensity, but does not contain an artificial radioactive material, You can send it out through the search bar.

If it is determined that the artificial radiation is present in the radionuclide detection step, an object isolation step is performed in which the object is moved according to an isolation search for separate management. The object that has been moved to the quarantine search in this way is separately managed such that more precise inspection is carried out while the object is safely isolated from the outside.

The third aspect of the present invention,

A radiation detector for measuring background energy spectrum data in the absence of an object and measuring object energy spectrum data in the presence of the object;

A calculation unit for performing count ratio calculation for an arbitrary energy value using energy spectrum data represented by a count according to energy obtained from the radiation detector; And

A judging unit for discriminating the radionuclides by analyzing the count ratio;

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A radiation detection apparatus is provided.

Hereinafter, the radiation detecting apparatus will be described in detail with reference to FIG.

Referring to FIG. 4, the radiation detection apparatus 100 of the present invention includes a radiation detector 110 for measuring background energy spectrum data in the absence of an object, and measuring object energy spectrum data in the presence of the object, A calculator 120 for performing a count ratio calculation for an arbitrary energy value using energy spectrum data represented by a count according to energy obtained from the detector 110 and a discriminator 120 for discriminating the radionuclides by analyzing the count ratio, (130).

The display unit 140 may further include a display unit 140 for displaying a radionuclide such that the user can recognize the radionuclide through the determination unit 130.

In order to discriminate the radionuclide, the radiation detecting apparatus 100 according to the present invention may include a memory unit 150 storing radionuclide type data, and a control unit 130 for storing data on a specific radiation source And a radionuclide discriminating unit 160 for discriminating radionuclides corresponding to the radionuclide data stored in the memory unit 150.

In the memory unit 150, the radionuclide type data is secured in advance for the specific radionuclide through the above-described radiation separation method, and classified and stored. These data can be used to acquire the data of each kind of radioactive nuclides through a plurality of experiments in the laboratory.

When the radionuclide is discriminated by the radionuclide discrimination unit 160, the radionuclide discrimination unit 160 displays the radionuclide on the display unit 140 so that the user can grasp it. Therefore, when the radioactive nuclide which is harmful to the human body is detected as a result of the measurement, it is possible to isolate the radioactive nuclide.

With such a configuration, the radiation detector 110 can use a conventional apparatus as it is. The radiation detector 110 can quickly scan the measurement space to secure data.

The calculation unit 120, the determination unit 130 and the nuclide identification unit 160 can derive the resultant values through simple calculations. Therefore, the data obtained through the radiation detector 110 can be obtained The user can be informed of the presence of artificial radiation by judging the radionuclide to the user.

For example, when a large quantity of goods is imported through a ship, there has been a problem that the reliability is somewhat low because the presence or absence of radiation is sampled by sampling a specific quantity of goods in the past. However, by using the radiation detecting apparatus 100 of the present invention, it is possible to scan all the containers loaded on a ship and to derive the result quickly and accurately. Therefore, it is possible to search all the imported goods, .

100: Radiation detection device
110: Radiation detector
120:
130:
140:
150:
160: Nuclide discrimination unit

Claims (8)

A method for detecting a radionuclide using energy spectrum data represented by a count according to an energy obtained from a radiation detector,
The background energy spectrum data measured without the object to detect the radionuclide and the object energy spectrum data measured in the presence of the object are used to divide the object energy spectrum data into arbitrary energy values into the background energy spectrum data and calculate the count ratio Calculating; And
Comparing the count ratio with a previously prepared radionuclide count ratio to distinguish radionuclides detected in an object;
Lt; / RTI >
The above-
Wherein the count value is a minimum energy value within a certain range from 1 and the energy value having the maximum count value is found and compared.
A method for detecting radionuclides.
delete delete delete The method according to claim 1,
Wherein the step of performing the count ratio calculation is performed while changing the energy value.
The method according to claim 1,
The count ratio may be,
Wherein the energy is defined within a predetermined arbitrary energy interval.
A method for detecting radionuclides.
1. A method for detecting a radionuclide using a radiation detector and a method for detecting the radionuclide of claim 1,
An energy spectrum data measurement step of measuring background energy spectrum data in the absence of an object with the radiation detector and measuring object energy spectrum data in the presence of an object with a radiation detector;
And when the count of the object energy spectrum data is equal to or larger than the detection reference value, the count ratio calculating step is performed to detect the radionuclide species;
Containing
Radionuclide detection process.
A radiation detector for measuring background energy spectrum data in the absence of an object and measuring object energy spectrum data in the presence of the object;
A calculation unit for performing count ratio calculation for an arbitrary energy value using energy spectrum data represented by a count according to energy obtained from the radiation detector; And
A judging unit for discriminating the radionuclide by comparing the count ratio with a previously prepared radionuclide counting ratio to find and compare an energy value with the count ratio being within a certain range from 1 or an energy value with the counting ratio being the maximum value;
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Radiation detection device.

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