JP2016090707A - Radiation simulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique that enables required measurement and simulation for an effect of an invisible radiation to a human body by simulatively visualizing the radiation.SOLUTION: A radiation visualizing device and a simulator are provided with a box body (10), a visible light source (30) that emits light by simulating the radiation in an internal space (20) formed by the box body (10), and an illuminance meter (40) that measures an illuminance of the light emitted by the visible light source (30). The box body (10) is formed in such a manner that the internal space (20) is shielded from light from the outside and reflection of a visible light emitted from the visible light source (30) is suppressed. A shielding wall (50) that reduces a part of the visible light emitted from the visible light source (30) is provided between a site where the illuminance meter (40) is installed and the visible light source (30). The visible light source (30) is installed at a lower part of the internal space (20) and provided with a surface light sources (32, 33) and a point light source (31) that emit light toward an upper part of the internal space (20).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a technique of a simulation experimental apparatus capable of visually experiencing and learning the physical properties of radiation.

In order to investigate the prior art related to the present invention, the prior patent technology was searched by the following search formula.
(Radiation + Radioactivity) x (Visualization + Visible) x (Pseudo + Simulation + Simulator)
Thirteen published patents were hit in this search formula, and Patent Document 1 and Patent Document 2 were extracted from them.

The technique disclosed in Patent Document 1 is a technique for establishing a technique for predicting the total amount of radiation exposure of workers working in a radiation irradiation facility before work.
Specifically, the nuclide of the activated structure is specified in advance, the radiation dose on the structure surface is calculated, and the dose equivalent rate in an arbitrary space is calculated. Furthermore, the exposure dose depending on the time axis of the worker is calculated from the spatial data and the time data related to the work operation.

  The technique disclosed in Patent Document 2 discloses a system for formulating a real-time radiotherapy plan used when radiotherapy is performed on one anatomical part preselected from an animal body.

These techniques are useful for prior information gathering for professionals whose occupation is to deal with radiation.
The technique disclosed in Patent Document 2 can be used not only to provide information to “a specific person” such as a patient who is scheduled to receive radiation therapy, but also to a person engaged in treatment using radiation. For a “patient who is scheduled to receive radiation therapy” as an example of a specific person, the positive effect of treatment of the disease is assumed. Therefore, the psychology that it is easy to accept the information provided even if it lacks specialized knowledge works.

JP 2000-212292 A JP 2004-41725 A

Patent Documents 1 and 2 described above can provide information to experts and specific persons (patients scheduled to receive radiation therapy), but are not suitable for providing information to an unspecified number of persons. There wasn't.
Here, the “unspecified number of people” are those who have excessive fear of radiation, those who have vague anxiety, and the like. For these “unspecified number of people”, the positive (plus) use of radiation such as treatment is not expected, and only the minus side of exposure is assumed, but radiation is invisible. Coupled with excessive fear and vague anxiety.

There is a need for a technology that contributes to the appropriate transmission of information on matters such as radiation, external exposure caused by radioactive materials, and decontamination of radioactive materials to an unspecified number of people who lack specialized knowledge.
There are almost similar needs in educational institutions that train specialists (for example, college medical schools and technical schools that train radiographers). This is because the students before becoming professionals are an unspecified number of people who lack specialized knowledge, and as an educational institution, it is required to properly convey correct knowledge and information.

For example, doctors engaged in X-rays and cancer treatments, and radiologists involved in X-ray imaging, etc., learn correct knowledge about external exposure from radiation as specialized knowledge during their student days.
However, in such a learning opportunity, even with the most advanced learning material, the learner can only play and view the learning video. There is no opportunity to conduct hands-on learning through simulation experiments because no device is provided that simulates using models or measuring devices.

The problem to be solved by the present invention is to visualize the radiation in terms of the properties related to invisible radiation, effective decontamination considering the properties, and effects on the human body, and perform necessary measurements and simulation experiments. It is to provide a technology that makes it possible.

In order to investigate the influence of radiation on living organisms, two points are important: measuring the intensity of the radiation per unit time and measuring the total amount of radiation irradiated.
An illuminometer is used for the light intensity. If the light source is a point light source, the light intensity is inversely proportional to the square of the distance from the point light source.
As for the total amount of light, any device that integrates the light intensity measured by the illuminometer is sufficient.
Based on the above, the present inventor has developed a device (simulator) that visualizes radiation in a simulated manner and enables necessary measurements and simulation experiments.

(Invention)
The present invention relates to a visible light source (30) that emits radiation in a box (10) and an internal space (20) formed by the box (10), and the visible light source (30). The present invention relates to a radiation visualization apparatus including an illuminance meter (40) for measuring emitted illuminance.
The box (10) is formed so as to block light from the outside with respect to the internal space (20) and to suppress reflection of visible light emitted by the visible light source (30),
Between the site where the illuminometer (40) is installed and the visible light source (30), a radiation simulator provided with a light shielding wall (50) that reduces a part of visible light emitted by the visible light source (30). is there.

(Glossary)
The “box (10)” is easy to use if it is a five-sided box that forms one side face so that it can be opened or does not exist.
The “visible light source (30)” is a light source that emits light that can be seen through the eyes, that is, light having a wavelength of 380 to 780 nanometers. For example, an LED light source is used. This is because the heat generated at the time of issuance is small and the safety is high.
Regarding the wavelength of light (that is, the color of light), any wavelength can be used as long as it is in the visible wavelength range. However, a wavelength that takes into account human relative visibility characteristics, for example, a sensitive green wavelength range may be employed. The same applies to the color (wavelength) of the above-described visible light source (30), but it may be white, which is a mixed color of all of red, green, and blue.

The “part where the illuminance meter (40) is installed” represents “indoor” in the internal space (20) in a simulated manner.
The unit of illuminance (lux) measured by the illuminometer (40) can be converted as a radiation dose rate (microsievert / hour).
The “light-shielding wall (50)” includes not only a material that can substantially transmit a visible light source but also a material that can almost completely shield it.

(Function)
The internal space (20) shields the light from the outside by the box (10) and suppresses the reflection of the visible light emitted by the visible light source (30), so the visible light emitted by the visible light source (30) Can be measured with a luminometer (40).
In the internal space (20) that schematically shows the room, a part of visible light emitted from the visible light source (30) is reduced by the light shielding wall (50). That is, it can be shown by the radiation simulator according to the present invention that the illuminance in a state where the visible light is reduced can be measured in the room separated from the light shielding wall (50).

(Variation 1 of the present invention)
The present invention is more preferably formed as follows.
That is, the visible light source (30) includes a surface light source (32, 33) that is installed in a lower portion of the internal space (20) and irradiates upward of the internal space (20). (32, 33) can be formed so that the part (21) close to the light shielding wall (50) is turned off and the other part (22) can be turned on.
The “surface light source (32, 33)” is formed by, for example, arranging a large number of small point light sources in a plane and combining it with a diffusion plate that diffuses the emitted visible light.

In areas contaminated with radioactivity (for example, around the Fukushima Daiichi Nuclear Power Station), radioactive materials adhere to the land and buildings over a wide area. The work to remove the attached radioactive material is called “decontamination work”. In other words, “decontamination work” is to eliminate the source of radiation by removing radioactive substances that emit radiation.
For the surface light source (32, 33), by turning off the part (32) close to the light-shielding wall (50) and enabling the other part (33) to turn on, for example, only about the part close to the space simulating the room A state in which the decontamination work is completed and the decontamination work of the distant part (32) is postponed can be simulated.

(Variation 2 of the present invention)
In the present invention, a point light source (31) may be provided as the visible light source, and the point light source (31) may be formed to be movable in the internal space (22).
A place where a large amount of radioactive material gathers compared to the surrounding area is called a “hot spot”. Hot spots are places where decontamination work should be preferentially performed.
The point light source (31) simulates a so-called hot spot in which the radiation value is very high compared to the surroundings.

(Function)
By performing and comparing illuminance measurement in the presence of a point light source (31) that simulates a hot spot and illuminance measurement with the point light source (31) that is a hot spot turned off, hot spot removal is performed. The effect of dyeing work can be simulated.
Further, it is possible to simulate the characteristics of a hot spot that can be regarded as a point source and the effect of distance attenuation by sequentially separating the illuminometer from the hot spot.

(Variation 3 of the present invention)
The present invention may include a moving body (60) movable in the internal space (20), and the illuminance meter (the illuminance sensor 41) may be attachable to the moving body (60).
When the illuminometer main body (40) and the illuminance sensor (41) can be separated, only the illuminance sensor (41) is attached to the moving body (60). In the case of separation, it does not matter whether it is wired or wireless.

(Function)
The moving body (60) can simulate human behavior in the internal space (20).

(Further variations of Variation 3)
Regarding the above-described variation 3 of the present invention, it is more preferable to add the following configuration.
That is, an integration device that integrates the total amount of illuminance measured by the illuminometer that can be attached to the mobile body, and an operation that simulates conversion of the integrated illuminance, which is the total amount of illuminance accumulated by the integration device, into radiation exposure dose An apparatus.

(Function)
The integrating device integrates the unit (lux / time) of integrated illuminance, and the integrated integrated illuminance is converted as an integrated dose (exposure dose / microsievert).
As a result, it is possible to simulate the human exposure dose when acting in a simulated manner.

(Variation 4 of the present invention)
The present invention may include an output device (for example, a liquid crystal monitor) capable of displaying a change in the illuminance measured by the illuminance meter (40) along the time axis.
If the illuminometer (40) can only measure instantaneous values, a separate calculation device will be provided to integrate the total amount of measurement time, and the integrated value accumulated by the calculation device will also be output to the output device. If possible, it is preferable.

The output device displays the illuminance measured by the illuminometer (40) along with the time axis. Based on the display, it is possible to simulate how to accumulate how much radiation was received in a predetermined time.

According to the present invention, it has been possible to provide a technique that makes it possible to make a necessary measurement or a simulation experiment by visualizing radiation about the influence on the human body caused by invisible radiation.

1 is a perspective view showing a first embodiment according to the present invention. It is an assembly perspective view showing a first embodiment according to the present invention. It is a graph which shows a mode that illumination intensity attenuate | damps with the distance from point light source LED imitating a hot spot. It is a graph which shows the transmittance | permeability to the room | chamber interior when the color and the number of light-shielding walls are changed. It is a graph which shows the illumination intensity at the time of changing a decontamination range and a decontamination place. It is a graph which shows the illumination intensity at the time of imitating human action.

  Embodiments of the present invention will be described below with reference to the drawings. The drawings used here are FIGS. 1 to 6.

In order to know the effects on the human body related to radioactivity (external exposure), it is premised on the distinction between radioactive substances and radiation (especially gamma rays) emitted by the radioactive substances. Radiation, like light, is a type of electromagnetic wave.
For example, external exposure caused by radioactive material (radiation emitted by the Fukushima Daiichi Nuclear Power Plant accident in March 2011) has become a social problem.

Now, the ideal decontamination work is to carry out all the contaminated areas quickly and uniformly. However, since the contaminated area covers a wide area, an efficient and effective decontamination work is desired. It can be said that it is impractical to implement all the contaminated areas promptly and uniformly.
In other words, an efficient and effective decontamination work will be performed around a base or living area where people live and are active. Since radiation is a kind of electromagnetic wave, if the shape of the radiation source is a point, the intensity of the radiation is inversely proportional to the square of the distance from the radiation source. Moreover, even if the shape of the radiation source is not a dot but a plane, it is attenuated as the distance increases because it is not an infinite flat plate or is attenuated by air.

For example, from the viewpoint of an individual's exposure dose indoors, it can be seen that if outdoor decontamination is performed in the vicinity of a residence, an effect that is almost the same as that obtained when decontamination work is performed in all regions can be obtained.
If a hot spot exists in the living area, the hot spot should be quickly decontaminated, but otherwise it is practical to set priorities.

On the other hand, those who do not have the correct knowledge of “external exposure to radiation” tend to want to “decontaminate all contaminated areas evenly and quickly”. As mentioned above, this is an unrealistic request. If unrealistic demands are generalized, it will hinder efficient and effective decontamination work.
It can be said that the dissemination of correct knowledge is indispensable in order to make effective use of time lapse and limited human resources. However, “radiation is invisible” makes it difficult to transfer correct knowledge to people who do not have correct knowledge.
For the situation described above, the apparatus according to the present embodiment makes it possible to visually simulate the effects of invisible radiation on the human body, enable necessary measurements and simulation experiments, and disseminate correct knowledge. Expected to contribute.

(FIGS. 1 and 2)
FIG. 1 and FIG. 2 show a visible light source 30 that emits radiation in the form of a five-sided box 10 with its front side open, and an internal space 20 formed by the box 10, and its visible This is a radiation visualization device including an illuminance meter 40 that measures the illuminance emitted by the light source 30.
The box 10 has a black outer surface in order to shield light from the outside from the internal space 20. Further, the inner surface is matte so as to suppress reflection of visible light emitted from the visible light source 30.

  The box top plate 11 was 600 mm wide and 400 mm deep. The side plate 12 is 350 millimeters long and the depth is 400 millimeters at the top. The lower part was 300 mm. The reason why the upper part is longer than the lower part is that the room is assumed as the environment where the present apparatus is placed, but in this case, the leakage of light from the outside such as a ceiling light is prevented.

Although the front side is opened, a front plate (not shown) for protecting the inside may be attached when carrying.
The above-mentioned size is a size necessary for seeing the simulation experiment and is a size adopted because it is reasonable as a portable size. Therefore, it is not intended that the present invention be limited to this size.

The bottom plate 13 of the box is provided with a light shielding wall fixture 19 to which a light shielding wall 50 for dividing the internal space 20 into two horizontally can be attached and detached. The light shielding wall fixture 19 can be equipped with two light shielding walls (first wall 51 and second wall 52). The number of light shielding walls may be more than two.
The left inner space in FIG. 1 imitates the indoor space 21 and the right inner space imitates the outdoor space 22 across the light shielding wall 50.

The visible light source 30 is a surface light source installed in the outdoor space 22, and an LED is used as an example.
A first surface light source 32 and a second surface light source 33 are installed below the bottom plate 13 in the outdoor space 22. Both the first surface light source 32 and the second surface light source 33 are formed by arranging a large number of point light sources, and the bottom plate 13, which is a translucent milky white acrylic plate, diffuses the light emitted from the LEDs. Therefore, it is a surface light source. Simulates the state of radioactive material adhering to the ground surface.

Lighting control such as turning off the first surface light source 32 and turning on the second surface light source 33 or turning on both the first surface light source 32 and the second surface light source 33 is possible. Instead of control, it may be configured to be removable instead of being extinguished.
As an example, the point light source 31 employs a green LED as a wavelength in consideration of human specific visual sensitivity characteristics, and is movable in the outdoor space 22. The LED is equipped with a translucent rubber light diffusion cap 31-1 in order to diffuse directional light in all directions as much as possible.

The light shielding wall 50 described above employs an acrylic plate having a thickness of 5 millimeters. There are several types, including those that can transmit a little visible light source, and those that can block almost completely. One of them can be installed, or two can be selected and installed. .
The relationship between the mounting variation and the illuminance will be described with reference to FIG.

The illuminometer 40 has a light receiving sensor 41 installed in the indoor space 21, measures the illuminance of the light received by the light receiving sensor 41, and digitally displays the measurement result on the liquid crystal screen. doing.
The light receiving sensor 41 is attached to a movable body 60 that is movable with respect to the bottom plate 13 in the box 10. That is, the moving body 60 and the light receiving sensor 41 attached to the moving body 60 can measure illuminance while moving the indoor space 21 and the outdoor space 22.

(Figure 3)
In FIG. 3, the light shielding wall 50 is removed while the point light source 31 is turned on, and the moving body 60 is fixed to a predetermined position in the indoor space 21. The result of measuring the illuminance of the light receiving sensor 41 while changing the distance between the light receiving sensor 41 and the point light source 31 is shown.
After measuring the distance between the light receiving sensor 41 and the point light source 31 from 3 centimeters to 15 centimeters 5 times every 3 centimeters, and subtracting this value with the value when the point light source 31 is turned off as the background The average value is plotted. For comparison, values that are inversely proportional to the square of the distance are plotted at positions 6, 9, 12, and 15 centimeters.

The error is considered to be caused by the fluctuation of the background described above.
As a result, it can be said that when the distance from the hot spot is doubled, the illuminance is attenuated to about 1/4.

(Fig. 4)
FIG. 4 shows how the illuminance of the indoor space 21 changes depending on the type of the light shielding wall.
In a state where the point light source 31 is turned on, it is installed at a predetermined position in the outdoor space 22 and fixed. In addition, the moving body 60 is fixed at a predetermined position in the indoor space 21. That is, the illuminance change was measured when the type of the light shielding wall was changed without changing the distance between the light receiving sensor 41 and the point light source 31.
Assuming that the measured illuminance without a light shielding wall is 100%, about 95% is transmitted when a colorless light shielding wall is employed.

When a yellow light-shielding wall is used, about 80% is transmitted. When an orange light shielding wall is used, about 35% is transmitted, and when a gray light shielding wall is used, about 18% is transmitted.
Further, when a red light shielding wall is employed, about 9% is transmitted, and when two gray light shielding walls are employed, about 5% is transmitted.

As described above, it can be confirmed by simulation that the transmittance (light shielding rate) varies depending on the type of the light shielding wall, and that the transmittance decreases by increasing the number of light shielding walls.
That is, even with actual radiation, it is a specification that can indirectly simulate that the transmittance (= 1−shielding rate) varies depending on the material and thickness of the shielding wall (building wall). For example, a yellow shading wall for radiation corresponds to a wooden house, and a gray shading wall corresponds to a concrete wall.

(Fig. 5)
In FIG. 5, the moving body 60 (that is, the light receiving sensor 41) is fixed to a predetermined position in the indoor space 21 without using the point light source 31, and experiments are performed using the surface light sources 32 and 33.
State 1 is a state in which both the first surface light source 32 and the second surface light source 33 are turned on, that is, a state in which decontamination work is not performed. Moreover, the state 4 imitates the state where both the first surface light source 32 and the second surface light source 33 are turned off, that is, the state where the decontamination work is completed.

Note that the illuminance of less than 40 lux is measured even in state 4 because light from the outside cannot be blocked (so-called background).
Based on the illuminance of state 1 (about 150 lux) and the illuminance of state 4 (about 40 lux), it can be assumed that the illuminance of about 110 lux is not decontaminating.

  State 2 shows a state where distant decontamination, that is, decontamination of a place far from the indoor space 21 is completed, but a place close to the indoor space 21 is not decontaminated. Specifically, the first surface light source 32 is turned on and the second surface light source 33 is turned off. The illuminance in this state is about 140 lux (about 100 lux if light from the outside is blocked). In other words, it means that the effect is only about 9%.

  State 3 shows a state in which the decontamination in the vicinity, that is, the decontamination of the place close to the indoor space 21 is completed, and the place far from the indoor space 21 is not decontaminated. Specifically, the first surface light source 32 is turned off and the second surface light source 33 is turned on. The illuminance in this state is about 50 lux, which means that a decontamination effect of 90% or more can be obtained.

  State 3 simulates the situation where decontamination of the place near the building has been completed and decontamination of the place far from the building has not been completed. It also means that a decontamination effect is obtained. If you understand this, for those who want something difficult to achieve, such as "decontamination of all contaminated areas, evenly and quickly", an efficient and effective decontamination work It can be said that it is easy to obtain understanding cooperation.

  Educational institutions that nurture doctors engaged in X-rays and cancer treatments, and radiologists involved in X-ray imaging, etc. will be effective learning materials as simulators that can simulate and experience correct knowledge about external radiation exposure. .

(Fig. 6)
FIG. 6 is a simulation experiment of radiation dose by an action pattern of moving from indoor to outdoor, passing through the vicinity of a hot spot, and returning indoors.
Since the illuminance changes greatly between the indoor and outdoor areas, the significance of the existence of the light shielding wall can be understood.
In addition, the illuminance increases rapidly in the vicinity of the hot spot, but if the staying time there is short, the proportion of the total integrated illuminance does not increase. From this, it can be understood that there is no need to be afraid of hot spots.

As described above, typical states and cases have been described, but various states are simulated by moving the point light source 31 and the moving body 60 and combining the lighting patterns of the surface light sources 32 and 33. Is possible.
In addition, since the present apparatus is portable, it can be easily carried out and explained together with a simulation experiment by taking it to a public place.

  The illuminometer 40 is not particularly mentioned in the description of FIG. 1 and FIG. 2, but is additionally provided with an arithmetic device (personal computer) that integrates the total amount of illuminance during the measurement time measured by the illuminometer 40. The integrated value integrated by the arithmetic unit can be output to the output monitor of the personal computer.

For the moving body 60, a rail may be laid on the upper surface of the bottom plate 13 and the measurement as shown in FIG. 6 may be executed. Further, a moving device that randomly moves the upper surface of the bottom plate 13 may be provided, or may be formed so as to be remotely operable.

The present invention can be used in the decontamination service industry that removes radioactive materials, the service industry such as medical treatment that handles radiation, the data service industry that operates such as data collection management of radiation measurement, the software development industry related to measurement data, the education industry, etc. Have sex.

DESCRIPTION OF SYMBOLS 10; Box 11: Top plate 12; Side plate 13; Bottom plate 19; Shading wall fixture 20; Interior space 21; Indoor space 22; Outdoor space 30; Visible light source 31; Point light source 31-1; ; First surface light source 33; second surface light source 40; illuminance meter 41; light receiving sensor 50; light shielding wall 51; first wall 52; second wall 60;

Claims (6)

A radiation visualization device comprising: a box, a visible light source that emits light in an internal space formed by the box, and an illuminometer that measures the illuminance emitted by the visible light source;
The box is formed so as to block light from the outside with respect to the internal space and to suppress reflection of visible light emitted by the visible light source,
A radiation simulator provided with a light shielding wall between the illuminometer and the visible light source for reducing a part of visible light emitted from the visible light source. The visible light source is provided at a lower portion of the internal space, and includes a surface light source that irradiates upward of the internal space.
The radiation simulator according to claim 1, wherein the surface light source is formed such that a portion close to the light shielding wall is turned off and other portions can be turned on. The visible light source includes a point light source,
The radiation simulator according to claim 1, wherein the point light source is formed to be movable in the internal space. Comprising a movable body movable in the internal space,
The radiation simulator according to any one of claims 1 to 3, wherein the illuminance meter is attachable to the moving body. An accumulator that integrates the total amount of illuminance measured by the illuminometer that can be attached to the moving body; and
The radiation simulator according to claim 4, further comprising: an arithmetic device that converts the integrated illuminance, which is the total amount of illuminance accumulated by the accumulator, into a radiation exposure dose in a simulated manner.   The radiation simulator according to any one of claims 1 to 5, further comprising an output device capable of displaying a change along with a time axis of the illuminance measured by the illuminometer.

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