KR102624618B1 - Radiation dose monitoring system and the method of thereof - Google Patents

Abstract

A daily radiation dose monitoring system is disclosed. A daily radiation dose monitoring system according to an embodiment of the present invention includes an examination data receiver that receives specimen information and radiation source information from a predetermined user terminal; an examination condition determination unit that retrieves radiation intensity data from a predetermined server based on the radiation source information and determines a threshold condition including a maximum exposure time and maximum exposure intensity based on the specimen information; and detecting whether a radiographic examination is performed, and if the radiographic examination is performed, calculating the radiation cumulative exposure time and radiation exposure amount of the specimen, and displaying the radiation intensity data and the radiation cumulative exposure through a preset display means. It includes a test monitoring unit that displays at least one of time and the cumulative radiation exposure amount.

Description

Daily radiation dose monitoring system and method {RADIATION DOSE MONITORING SYSTEM AND THE METHOD OF THEREOF}

The present invention relates to a radiation dose monitoring system and method, and more specifically, to daily radiation dose monitoring that leads to more accurate radiographic examination by checking the radiation intensity and setting an appropriate exposure time based on the thickness of the specimen. It relates to systems and methods.

In general, non-destructive testing means checking for defects in structures built on land, on board, etc. Non-destructive testing uses media such as radiation, ultrasound, and laser.

In general, non-destructive testing using radiation uses the same method as the radiation testing used on the human body, for example, X-ray imaging. In other words, a radiation source that generates radiation is placed on one side of the structure to be measured, and the other side of the structure is inspected to see whether there is a defect in the structure by measuring the amount of radiation emitted from the radiation source that has passed through the structure. . In particular, non-destructive testing is widely used to inspect welded areas in welding pipes or ships that transport fluids.

This non-destructive test usually uses radiation to inspect the presence or absence of defects in the welded area. Non-destructive testing using radiation is a method of inspecting internal defects in an object to be inspected by transmitting radiation such as . An example of such non-destructive testing equipment is disclosed in Korean Registration Model Publication No. 20-043664.

However, in general, the radiation emitted from non-destructive testing equipment using radiation is harmful to workers. In particular, if a worker is exposed to radiation emitted from the equipment at close range, it can cause fatal damage to the body. Therefore, it is very important to protect workers who use non-destructive equipment using radiation, and when inspecting a structure installed in a crowded place, it is necessary to protect people moving around the structure from radiation emitted from the equipment.

Therefore, there is a need for research on a radiation source monitoring system and method that can guide radiography tests to be performed safely and manage them more effectively by converting radiography tests into test log data.

The present invention calculates the intensity of the radiation source based on the product information of the radiation source used in radiographic examination and determines critical conditions including the maximum exposure time and maximum exposure amount, thereby allowing the operator to confirm the product information of the radiation source in documents. The purpose is to provide a daily radiation dose monitoring system and method that can automatically check the intensity data of the radiation source without the need for it and lead to safer radiography inspection based on critical conditions.

In addition, the start and end of the radiography examination is received from the user terminal, and an examination log for the radiography examination is automatically created, allowing daily radiation dose monitoring to more easily dataize and manage information on the radiography examination. The purpose is to provide a system and method.

The problems to be solved by the present invention are not limited to the problems mentioned above, and other problems to be solved by the present invention that are not mentioned herein can be explained to those skilled in the art from the description below. You will be able to understand it clearly.

The daily radiation dose monitoring system according to an embodiment of the present invention includes an examination data receiver that receives specimen information and radiation source information from a predetermined user terminal, calls radiation intensity data from a predetermined server based on the radiation source information, and adds the specimen information to the specimen information. Based on this, a test condition determination unit determines critical conditions including the maximum exposure time and maximum exposure intensity, and detects whether a radiographic test is performed, and if a radiographic test is performed, the cumulative radiation exposure time and the cumulative radiation exposure amount of the specimen. Calculates and includes an inspection monitoring unit that displays at least one of radiation intensity data, radiation cumulative exposure time, and radiation cumulative exposure amount through a preset display means.

In addition, the test data receiving unit is a specimen information collection unit that receives at least one of the thickness of the specimen on which radiographic examination is performed and the distance to the radiation source, and a radiation source information collection unit that receives at least one of the manufacturer and product number of the radiation source. It includes a test condition determination unit, an intensity data call unit that calls radiation intensity data corresponding to the radiation source information received in the radiation source information collection unit from a server, radiation intensity data called from the server, and a specimen received in the specimen information collection unit. It is characterized by comprising an exposure condition determination unit that calculates the maximum exposure time and maximum exposure intensity based on the thickness of and the distance between the radiation source and the specimen.

In addition, the test monitoring unit is linked to a radiation irradiation device that emits a radiation source, a radiation source generation detection unit that recognizes whether a radiation source is irradiated to the specimen through the radiation irradiation device, and a test condition determination unit when a radiation source is irradiated to the specimen. A display control unit that controls the daily intensity data calculated based on the radiation intensity data called from the display means to be displayed on the display means, an exposure time monitoring unit that calculates the radiation cumulative exposure time of the specimen, based on the radiation intensity data and the radiation cumulative exposure time. It is characterized by comprising a cumulative amount monitoring unit that calculates the cumulative radiation exposure amount of the specimen and a radiation exposure risk determination unit that determines whether at least one of the cumulative radiation exposure time and the cumulative radiation exposure amount exceeds a critical condition.

In addition, the display control unit is characterized in that it calculates daily intensity data based on the radioisotope attenuation formula of [Equation 1].

[Equation 1]

RDaily intensity data = Exp(-0.693t/T)

R

(In this case, T is the half-life time of the source, R is the radioactivity size, and t means the elapsed time)

In addition, an inspection log generator that receives start and end status information of the radiography examination from the user terminal and automatically generates inspection log data based on the data calculated by the inspection monitoring unit when the end status information is input from the user terminal. Additionally, the inspection log creation unit may include a data transmission unit that transmits the inspection log data to the user terminal and a data backup unit that transmits the inspection log data to a predetermined backup server.

The daily radiation dose monitoring system and method of the present invention calculate the intensity of the radiation source based on the product information of the radiation source used in radiography, and determine critical conditions including the maximum exposure time and maximum exposure amount, so that the operator can It is possible to automatically check the intensity data of the radiation source without having to check the product information of the radiation source in documents, and has the effect of inducing safer radiography inspection to be performed based on critical conditions.

In addition, by receiving information about the start and end of a radiography examination from the user terminal and automatically creating an examination log for the radiography examination, information on the radiography examination can be more easily converted into data and managed.

Figure 1 is a configuration diagram of a daily radiation dose monitoring system according to an embodiment of the present invention.
Figure 2 is a diagram for explaining the inspection data receiving unit of the daily radiation dose monitoring system according to an embodiment of the present invention.
Figure 3 is a diagram for explaining the inspection condition determination unit of the daily radiation dose monitoring system according to an embodiment of the present invention.
Figure 4 is a diagram for explaining the inspection monitoring unit of the daily radiation dose monitoring system according to an embodiment of the present invention.
Figure 5 is a diagram for explaining the inspection log creation unit of the daily radiation dose monitoring system according to an embodiment of the present invention.
Figure 6 is a diagram for explaining the display means of the daily radiation dose monitoring system according to an embodiment of the present invention.

Specific details, including the problem to be solved by the present invention, the means for solving the problem, and the effect of the invention, are included in the examples and drawings described below. The advantages and features of the present invention and methods for achieving them will become clear by referring to the embodiments described in detail below along with the accompanying drawings.

Hereinafter, the present invention will be described in more detail with reference to the attached drawings.

Figure 1 is a configuration diagram of a daily radiation dose monitoring system according to an embodiment of the present invention, Figure 2 is a diagram illustrating the inspection data receiver of the daily radiation dose monitoring system according to an embodiment of the present invention, and Figure 3 is a diagram for explaining the inspection condition determination unit of the daily radiation dose monitoring system according to an embodiment of the present invention, and Figure 4 is a diagram for explaining the inspection monitoring unit of the daily radiation dose monitoring system according to an embodiment of the present invention. , FIG. 5 is a diagram for explaining the inspection log creation unit of the daily radiation dose monitoring system according to an embodiment of the present invention, and FIG. 6 is a diagram for explaining the display means of the daily radiation dose monitoring system according to an embodiment of the present invention. This is a drawing for

<Example 1>

Referring to FIG. 1, the daily radiation dose monitoring system 100 according to an embodiment of the present invention may include an examination data receiving unit 110, an examination condition determination unit 120, and an examination monitoring unit 130.

The test data receiving unit 110 receives specimen information and radiation source information from a predetermined user terminal, and the test condition determination unit 120 retrieves radiation intensity data from a predetermined server based on the radiation source information, and collects the specimen. Based on the information, critical conditions including maximum exposure time and maximum exposure intensity are determined, and the test monitoring unit 130 detects whether a radiography test is performed, and when the radiography test is performed, the specimen The cumulative radiation exposure time and the cumulative radiation exposure amount can be calculated, and at least one of the radiation intensity data, the radiation cumulative exposure time, and the radiation cumulative exposure amount can be displayed through a preset display means.

More specifically, referring to FIGS. 2 to 4, the test data receiver 110 is a specimen information collection unit that receives at least one of the thickness of the specimen on which the radiographic examination is performed and the distance from the radiation source. (111) and a radiation source information collection unit 112 that receives at least one of the manufacturer and product number of the radiation source.

For example, the server stores radiation intensity data of the radiation generating device by manufacturer and product number of the radiation source, and can receive the product number and manufacturer of the radiation generating device used in the radiographic examination from the user terminal. there is.

In addition, the test condition determination unit 120 includes an intensity data call unit 121 that calls the radiation intensity data corresponding to the radiation source information received by the radiation source information collection unit 112 from the server, and a call intensity data call unit 121 that calls the radiation intensity data from the server. An exposure condition determination unit ( 122) may be included.

More specifically, the intensity data call unit 121 searches the server for data matching the product number and manufacturer of the radiation generating device input to the radiation source information collection unit 112, and detects the radiation included in the searched data. Intensity data can be recalled.

When the radiation intensity data is called through the intensity data call unit 121, the exposure condition determination unit ( 122) can determine critical conditions including the maximum exposure time and maximum exposure intensity required during the radiographic examination.

Accordingly, the maximum exposure conditions and maximum exposure intensity are determined based on the information on the radiation source and the specimen, thereby leading to a safer radiographic examination.

Meanwhile, the test monitoring unit 130 includes a radiation source generation detection unit 131 that is linked to a radiation irradiation device that emits the radiation source and recognizes whether the radiation source is irradiated to the specimen through the radiation irradiation device. When a radiation source is irradiated to the specimen, a display control unit 132 that controls the daily intensity data calculated based on the radiation intensity data called from the test condition determination unit 120 to be displayed on the display means, An exposure time monitoring unit 133 that calculates the cumulative radiation exposure time, a cumulative amount monitoring unit 134 that calculates the cumulative radiation exposure of the specimen based on the radiation intensity data and the cumulative radiation exposure time, and the cumulative radiation exposure time and It may include a radiation exposure risk determination unit 135 that determines whether at least one of the cumulative radiation exposure amounts exceeds the threshold condition.

For example, the radiation source generation detection unit 131 may monitor the operation of the radiation irradiation device through wireless network communication, and if wireless network communication with the radiation irradiation device is not possible, the radiation source generation detection unit 131 may irradiate the radiation through the user terminal. You can also receive input as to whether the device is operating.

As another example, the radiation exposure risk determination unit 135 determines whether at least one of the cumulative radiation exposure time and the cumulative radiation exposure amount exceeds the threshold condition, and the inspection condition determination unit 120 It may further include a critical condition correction unit that corrects 90% of the determined maximum exposure time and maximum exposure amount to become the critical condition.

Accordingly, the radiation exposure risk determination unit 135 may correct the initial critical condition determined by the examination condition determination unit 120 to enable a safer radiographic examination to be performed.

In addition, if at least one of the cumulative radiation exposure time and the cumulative radiation exposure amount exceeds the threshold condition in the radiation exposure risk determination unit 135, the radiation exposure device and the wireless The operation of the radiation irradiation device capable of network communication can also be forcibly stopped.

Meanwhile, in the radiation exposure risk determination unit 135, when at least one of the cumulative radiation exposure time and the cumulative radiation exposure amount exceeds the threshold condition and wireless network communication with the radiation irradiation device is impossible, the user terminal A radiation exposure risk notification signal may be transmitted to induce temporary suspension of the radiography examination.

Meanwhile, the display control unit 132 can calculate daily intensity data based on the radioisotope attenuation equation shown in [Equation 1] below.

[Equation 1]

RDaily intensity data = Exp(-0.693t/T)

R

(In this case, T is the half-life time of the source, R is the radioactivity size, and t means the elapsed time)

For example, the daily intensity data calculated through [Equation 1] may be displayed up to one decimal place on the display means.

More specifically, as shown in FIG. 6, the display means 30 has a space provided inside, a housing 31 in which a control board and a communication module are mounted, the current date and time, and the display control unit 132. ), a panel 32 on which the calculated daily intensity data, etc. are displayed, an operation button 33 for turning on and off the power of the display means 30, a power supply unit 34 for supplying power, and a detachable irradiation device. It may include attachment means (35).

At this time, the panel 32 may be provided in either a segment shape or an LCD display liquid crystal form.

For example, the power supply unit 34 may be provided in the form of a battery socket, and power may be supplied to the display means 30 by inserting a battery.

As another example, the attachment means 35 may be made of adhesive material (Velcro, etc.) to be fastened to the radiation irradiation device, or may include fastening means such as a buckle or magnet.

Meanwhile, the display control unit 132 controls to display the daily intensity data through the display means 30, and calculates the data from the exposure time monitoring unit 133 and the exposure amount monitoring unit 134 at each preset period. You can also control the cumulative exposure time and cumulative exposure amount to be displayed alternately.

Accordingly, the worker can check the cumulative exposure time and cumulative exposure amount displayed on the display means 30 to prevent radiation accidents such as radiation exposure.

As shown in FIG. 5, the daily radiation dose monitoring system 100 receives start and end status information of the radiography from the user terminal 10, and the end status information is received from the user terminal 10. When input, it may further include an inspection log generator 160 that automatically generates inspection log data based on the data calculated by the inspection monitoring unit 130.

More specifically, the inspection log generator 160 transmits the inspection log data to the user terminal 10, a data transmission unit 161, and the inspection log data to a predetermined backup server 20. It may include a data backup unit 162.

For example, the backup server 20 may be the same server as the server where radiation intensity data is stored corresponding to the product number and manufacturer of the radiation generating device.

Therefore, as soon as the radiography examination is completed, examination log data including sample information used in the radiography examination, information on the radiation source, cumulative exposure time, and cumulative exposure amount are automatically generated and transmitted to the user terminal, and the user Additional test results may be input through the terminal, and test log data containing the radiography test results may be transmitted to the backup server.

Meanwhile, the inspection monitoring unit 130 receives and analyzes data calculating the intensity of the radiation source generated through the radiation irradiation device in order to determine whether noise is generated due to foreign substances, etc. attached to the radiation irradiation device. It may further include a monitoring unit (not shown).

In other words, if a foreign substance is attached to the surface of the radiation irradiation device, the data calculating the radiation intensity will show an irregular or irregular pattern, and taking these characteristics into account, it is possible to determine whether a foreign substance is attached and further determine an error. It can happen.

To this end, the error monitoring unit (not shown) calculates the average and standard deviation of a plurality of radiation intensity data values calculated over a preset time, and data values that deviate from the standard deviation from the average among the plurality of radiation intensity data values ( If more than a preset number (ex. 5) is present (hereinafter referred to as 'noise data'), it can be assumed that a foreign substance is attached to the surface of the radiation irradiation device.

At the same time, the measured time interval of each of the noise data can be calculated, and if the time interval is not constant, it can be confirmed that a foreign substance is attached to the sensor surface.

Here, whether the time interval is not constant is determined by the maximum difference value (M _d ) between the time intervals between noise data calculated according to [Equation 2] below, and the time interval between noise data calculated according to [Equation 3] If the average value (T _av ) exceeds a constant multiple (ex. 2) or more, it can be determined that the time interval is not constant.

[Equation 2]

Here, M _d is the maximum difference in time interval between noise data, N _max is the maximum value in noise data time interval, and N _min is the minimum value in noise data time interval.

[Equation 3]

Here, T _av is the average value of the time interval between noise data, T _{(i-1) to i} is the time interval between the i-1th noise data and the ith noise data, and T _{0 to 1} is the time of sensor operation and the first noise data. The time interval from the appearance point and n represent the number of noise data.

For example, as shown in <Table 1> below, the data from T ₀ to T ₂₀ is 9, 10, 11, 12, 14, 18, 9, 9, 6, 13, 2, 8, 9, 9, 10, 17, In the case of 9, 10, 3, and 12, the average is 10 and the standard deviation is 3.42, so there are 6 noise data: 14, 18, 6, 2, 17, and 3. Since the number of noises is more than the preset number of 5, it can be assumed that foreign substances are attached to the sensor surface.

<Table 1>

Afterwards, when calculating whether the noise appeared irregularly according to [Equation 2] and [Equation 3], the maximum difference in time interval between noise data (M _d ) is 8-1=7, as shown in <Table 2> below. , and the average value of the time interval between noise data (T _av ) is 3.5.

<Table 2>

Therefore, since the maximum difference in time interval between noise data (M _d ) 7 is more than twice the average value of time interval between noise data (T _av ) 3.5, it can be confirmed that foreign matter is attached to the sensor surface in this case. .

<Example 2>

Meanwhile, the daily radiation dose monitoring method of the daily radiation dose monitoring system 100 according to an embodiment of the present invention is at least one of the thickness of the specimen on which the radiographic examination input from the user terminal is performed and the distance from the radiation source. A first step in which the specimen information collection unit 111 receives, a first step in which the radiation source information collection unit 112 receives at least one of the manufacturer and product number of the radiation source used for radiographic examination input from the user terminal. Step 2, the intensity data call unit 121 calls the radiation intensity data corresponding to the radiation source information received by the radiation source information collection unit 112 from the server, the third step, the radiation called from the server The exposure condition determination unit 122 calculates the maximum exposure time and the maximum exposure intensity based on intensity data, the thickness of the specimen received by the specimen information collection unit 111, and the distance between the radiation source and the specimen. A fourth step, a fifth step in which the radiation source generation detection unit 131 recognizes whether the radiation source is irradiated to the specimen through the radiation irradiation device, the exposure time monitoring unit 133 determines the cumulative radiation exposure time of the specimen. ) calculates the cumulative radiation exposure amount of the specimen based on the radiation intensity data and the radiation cumulative exposure time, and the seventh step in which the cumulative radiation exposure monitoring unit 134 calculates the cumulative radiation exposure time and the radiation. It may include an eighth step of the radiation exposure risk determination unit 135 determining whether at least one of the accumulated exposure amounts exceeds the threshold condition and transmitting the determination result to the user terminal.

According to the effect of the present invention as described above, the intensity of the radiation source is calculated based on the product information of the radiation source used in radiographic examination, and critical conditions including the maximum exposure time and maximum exposure amount are determined, thereby allowing the operator to use the radiation source. A daily radiation dose monitoring system and method can be provided that can automatically check the intensity data of the radiation source without the need to verify the product information in documents and induce safer radiography to be performed based on critical conditions.

In addition, the start and end of the radiography examination is received from the user terminal, and an examination log for the radiography examination is automatically created, allowing daily radiation dose monitoring to more easily dataize and manage information on the radiography examination. A system and method may be provided.

Additionally, the control method of the daily radiation dose monitoring system according to an embodiment of the present invention may be recorded on a computer-readable medium including program instructions for performing various computer-implemented operations. The computer-readable medium may include program instructions, data files, data structures, etc., singly or in combination. The medium may have program instructions specifically designed and configured for the present invention, or may be known and available to those skilled in the art of computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical media such as CD-ROMs and DVDs, and magnetic media such as floptical disks. -Includes optical media (magneto-optical media) and hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, flash memory, etc. Examples of program instructions include machine language code, such as that produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter, etc.

As described above, although one embodiment of the present invention has been described with limited examples and drawings, one embodiment of the present invention is not limited to the above-described embodiment, which is based on common knowledge in the field to which the present invention pertains. Anyone who has the knowledge can make various modifications and variations from this description. Accordingly, one embodiment of the present invention should be understood only by the scope of the claims set forth below, and all equivalent or equivalent modifications thereof shall fall within the scope of the spirit of the present invention.

10: user terminal 20: backup server
30: display means
110: Test data receiving unit 111: Sample information collection unit
112: Radiation source information collection department
120: Inspection condition determination unit 121: Strength data call unit
122: Exposure condition determination unit
130: Inspection monitoring unit 131: Radiation source generation detection unit
132: display control unit
133: Exposure time monitoring unit
134: Cumulative amount monitoring unit
135: Exposure risk determination unit
140: Inspection log creation unit

Claims (5)

a test data receiving unit that receives sample information and radiation source information from a predetermined user terminal;
an examination condition determination unit that retrieves radiation intensity data from a predetermined server based on the radiation source information and determines a threshold condition including a maximum exposure time and maximum exposure intensity based on the specimen information; and
Detects whether a radiographic examination is performed, calculates the radiation cumulative exposure time and radiation exposure amount of the specimen when the radiographic examination is performed, and displays the radiation intensity data and the radiation cumulative exposure time through a preset display means. And a test monitoring unit that displays at least one of the cumulative radiation exposure amounts,

The inspection data receiving unit,
a specimen information collection unit that receives at least one of the thickness of the specimen on which the radiographic examination is performed and the distance from the radiation source; and
It includes a radiation source information collection unit that receives at least one of the manufacturer and product number of the radiation source,

The inspection condition determination unit,
an intensity data call unit that calls the radiation intensity data corresponding to the radiation source information received by the radiation source information collection unit from the server; and
An exposure condition determination unit that calculates the maximum exposure time and the maximum exposure intensity based on the radiation intensity data called from the server, the thickness of the specimen received by the specimen information collection unit, and the distance between the radiation source and the specimen. Contains ;,

The inspection monitoring unit,
a radiation source generation detection unit that is linked to a radiation irradiation device that emits the radiation source and recognizes whether the radiation source is irradiated to the specimen through the radiation irradiation device;
When the radiation source is irradiated to the specimen, a display control unit that controls the daily intensity data calculated based on the radiation intensity data retrieved from the test condition determination unit to be displayed on the display means;
an exposure time monitoring unit that calculates the cumulative radiation exposure time of the specimen;
a cumulative dose monitoring unit that calculates the cumulative radiation exposure of the specimen based on the radiation intensity data and the cumulative radiation exposure time; and
It includes a radiation exposure risk determination unit that determines whether at least one of the cumulative radiation exposure time and the cumulative radiation exposure amount exceeds the threshold condition,

The display control unit,
Calculate daily intensity data based on the radioisotope attenuation formula of [Equation 1] below,

[Equation 1]
Daily intensity data = Exp(-0.693t/T)

R
(In this case, T is the half-life time of the source, R is the radioactivity size, and t means the elapsed time)

The display control unit,
Controlling the display means to display the radiation cumulative exposure time and the radiation cumulative exposure amount calculated by the exposure time monitoring unit and the cumulative amount monitoring unit at each preset period,

An examination log that receives start and end status information of the radiography examination from the user terminal, and automatically generates examination log data based on the data calculated by the examination monitoring unit when end status information is input from the user terminal. It further includes a generating unit;

The inspection log creation unit,
A data transmission unit transmitting the inspection log data to the user terminal; and
It includes a data backup unit that transmits the inspection log data to a predetermined backup server,

The inspection monitoring unit,
It further includes an error monitoring unit that analyzes the radiation intensity data that calculates the intensity of the radiation source generated through the radiation irradiation device and determines whether an error has occurred in the radiation irradiation device,

The error monitoring unit,
Calculate the average and standard deviation of the radiation intensity data calculated during a preset time, and determine whether the number of noise data, which is radiation intensity data that deviates from the standard deviation from the average, exists more than a preset number, and the radiation irradiation device It is assumed that foreign substances are attached to the surface of
By calculating the time interval at which the noise data was measured, the maximum difference value (M _d ) between the time intervals between the noise data calculated according to [Equation 2] below is the average value of the time interval between noise data calculated according to [Equation 3] below. A daily radiation dose monitoring system, characterized in that it is determined that foreign matter is attached to the surface of the radiation irradiation device when (T _av ) exceeds a preset constant multiple.

[Equation 2]

(Here, M _d is the maximum difference in time interval between noise data, N _max is the maximum value in noise data time interval, and N _min is the minimum value in noise data time interval)

[Equation 3]

(Here, T _av is the average value of the time interval between noise data, T _{(i-1) to i} is the time interval between the i-1th noise data and the ith noise data, and T _{0 to 1} is the time of operation of the irradiation device and the first Time interval from when noise data appears, n refers to the number of noise data)


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