JP7366581B2 - Thermoluminescent sheet reading method and thermoluminescent sheet reading device - Google Patents

Description

The present invention relates to a thermoluminescent sheet reading method for reading fluorescence emitted from a thermoluminescent sheet irradiated with radiation, a cassette for holding the thermoluminescent sheet, and a thermoluminescent sheet reading device equipped with the cassette.

Conventionally, there are radiation dosimeters that detect radiation exposure locations, exposure amounts, and the like. As a radiation dosimeter, for example, there is a TLD (Thermoluminescent Dosimeter) that emits fluorescence when a portion exposed to radiation is heated. Furthermore, conventionally, there is a reading device that measures (in other words, reads) fluorescence emitted from a thermoluminescent sheet, which is an example of a TLD (for example, see Patent Document 1).

The thermofluorescent image reading device disclosed in Patent Document 1 includes a sample sheet (thermofluorescent sheet) made from a mixture of thermofluorescent material, glass, synthetic resin, etc., and a heating section that heats the thermofluorescent sheet. , an installation section in which a thermoluminescent sheet is installed, and an imaging section that reads fluorescence emitted from the thermoluminescent sheet.

JP2014-28913A

By the way, a thermoluminescent sheet may be deformed by heat when heated. When the thermoluminescent sheet is deformed, the imaging unit cannot accurately read the two-dimensional distribution of fluorescence emitted from the thermoluminescent sheet.

The present invention provides a thermoluminescent sheet reading method that can suppress deformation of a thermoluminescent sheet.

A thermoluminescent sheet reading method according to one aspect of the present invention is a thermoluminescent sheet reading method that reads a two-dimensional distribution of fluorescence emitted from a thermoluminescent sheet, the method comprising: and an imaging step of reading fluorescence emitted from the thermoluminescent sheet heated in the heating step.

According to this, rapid heating of the thermoluminescent sheet is suppressed. In particular, if the thermoluminescent sheet contains a volatile substance such as toluene, it may vaporize due to a sudden temperature rise. When such a substance evaporates, bubbles are generated in the thermoluminescent sheet and the sheet is deformed. Therefore, by increasing the temperature of the thermoluminescent sheet at a temperature increase rate of 15° C./min or less, rapid vaporization of such substances is suppressed. Thereby, deformation of the thermoluminescent sheet is suppressed.

Further, for example, in the heating step, the temperature of the thermoluminescent sheet is increased from 100° C. or lower to 200° C. or higher at a temperature increase rate of 15° C./min or lower.

According to this, a rapid temperature rise of the thermoluminescent sheet is suppressed in a high temperature state. Therefore, deformation of the thermoluminescent sheet is further suppressed.

Further, for example, the heating step includes a first heating step of raising the temperature of the thermoluminescent sheet to 100° C., and after the first heating step, raising the temperature of the thermoluminescent sheet to 200° C. or less at a temperature increase rate of 15° C./min or less. and a second heating step of raising the temperature to .degree. C. or higher.

It is thought that the lower the rate of temperature rise of the thermoluminescent sheet, the less the thermoluminescent sheet deforms. However, the lower the temperature rise rate of the thermoluminescent sheet, the more time is required to read the fluorescence emitted from the thermoluminescent sheet. Therefore, heating is performed at a temperature increase rate of 15° C./min or less, particularly at a high temperature of about 100° C. to 200° C., where volatile substances such as toluene easily vaporize. Thereby, deformation of the thermoluminescent sheet can be suppressed, and the time taken to read fluorescence can be suppressed from increasing.

Further, for example, in the second heating step, the temperature of the thermoluminescent sheet is increased over 8 minutes or more so that the temperature of the thermoluminescent sheet becomes 200° C. or higher.

According to this, in a high temperature state, a rapid temperature rise of the thermoluminescent sheet is further suppressed. Therefore, deformation of the thermoluminescent sheet is further suppressed.

Further, for example, the thermoluminescent sheet reading method according to one aspect of the present invention further includes a placing step of placing a thermally conductive sheet on the thermoluminescent sheet, and in the heating step, the heating section is connected to the thermally conductive sheet. The thermoluminescent sheet is brought into contact with the sheet and heated by the heating section through the thermally conductive sheet.

According to this, since the thermoluminescent sheet is heated by the heating section via the thermally conductive sheet, appropriate temperature changes can be achieved over time by appropriately selecting the thickness, material, etc. of the thermally conductive sheet. The thermoluminescent sheet can be heated like this. Therefore, deformation of the thermoluminescent sheet is further suppressed.

Further, for example, the thickness of the heat conductive sheet is 0.5 mm or more.

According to this, it becomes easier to suppress the rapid temperature rise of the thermoluminescent sheet by the thermally conductive sheet, and it becomes easier to heat the thermoluminescent sheet so that the temperature changes appropriately over time. Therefore, deformation of the thermoluminescent sheet is further suppressed.

Further, for example, the material of the thermally conductive sheet is polytetrafluoroethylene or fluororubber.

These materials have lower thermal conductivity and are less likely to be deformed by heat than, for example, materials such as aluminum that are widely used in thermally conductive sheets. Therefore, by using these materials for the heat conductive sheet, the thermoluminescent sheet can be heated so that the temperature changes appropriately over time, and the heat conductive sheet can be made difficult to deform due to heat.

Further, for example, the heat conductive sheet is black.

For example, in a device that executes the thermoluminescent sheet reading method according to the present invention, light emitted from the thermoluminescent sheet may be diffusely reflected. Therefore, since the heat conductive sheet is black, such diffusely reflected light is absorbed by the heat conductive sheet. This makes it difficult for the diffusely reflected light to enter the camera that reads the fluorescence emitted from the thermoluminescent sheet, so the accuracy of reading the fluorescence in the camera is improved.

Further, a cassette according to one aspect of the present invention includes a glass plate having a translucent property that transmits fluorescence emitted from a thermoluminescent sheet, a thermally conductive sheet having a thickness of 0.5 mm or more, the glass plate and the thermally conductive sheet. A frame body that supports the glass plate and the thermally conductive sheet is provided so as to be switchable between a state where the thermoluminescent sheet is sandwiched between the conductive sheets and a state where the thermoluminescent sheet is not sandwiched between the conductive sheets.

According to such a configuration, when heating a thermoluminescent sheet using the cassette according to the present invention, the thermoluminescent sheet can be heated via the thermally conductive sheet. In particular, by setting the thickness of the heat conductive sheet to 0.5 mm or more, the thermoluminescent sheet can be heated so that the temperature changes appropriately over time. Therefore, deformation of the thermoluminescent sheet is suppressed.

Further, for example, the material of the thermally conductive sheet is polytetrafluoroethylene or fluororubber.

These materials have low thermal conductivity and are not easily deformed by heat. Therefore, by using these materials for the heat conductive sheet, the thermoluminescent sheet can be heated so that the temperature changes appropriately over time, and the heat conductive sheet can be made difficult to deform due to heat.

Further, for example, the heat conductive sheet is black.

According to this, in the device in which the cassette according to the present invention is used, light emitted from the thermoluminescent sheet may be diffusely reflected between the thermoluminescent sheet and the thermally conductive sheet. Therefore, since the heat conductive sheet is black, such diffusely reflected light is absorbed by the heat conductive sheet. This makes it difficult for the diffusely reflected light to enter the camera that reads the fluorescence emitted from the thermoluminescent sheet, so the accuracy of reading the fluorescence in the camera is improved.

Further, the thermoluminescent sheet reading device according to one aspect of the present invention includes the cassette, a heating unit that comes into contact with the thermally conductive sheet and heats the thermoluminescent sheet via the thermally conductive sheet, and the thermoluminescent sheet. and an imaging unit that reads fluorescence emitted from the camera.

According to this, the thermoluminescent sheet can be heated via the heat conductive sheet provided in the cassette. In particular, when the thickness of the heat conductive sheet is 0.5 mm or more, the thermoluminescent sheet can be heated so that the temperature changes appropriately over time. Therefore, deformation of the thermoluminescent sheet is suppressed.

According to the thermoluminescent sheet reading method according to one aspect of the present invention, deformation of the thermoluminescent sheet can be suppressed.

FIG. 1 is a perspective view showing the front appearance of a thermoluminescent sheet reading device according to an embodiment. FIG. 2 is a perspective view showing the appearance of the back side of the thermoluminescent sheet reading device according to the embodiment. FIG. 3 is a perspective view showing the internal structure of the front side of the thermoluminescent sheet reading device according to the embodiment. FIG. 4 is a block diagram showing the characteristic functional configuration of the thermoluminescent sheet reading device according to the embodiment. FIG. 5 is a perspective view showing the appearance of the cassette according to the embodiment. FIG. 6 is a perspective view showing the appearance of the cassette according to the embodiment when the heat conductive sheet is opened. FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 5, showing the cassette according to the embodiment. FIG. 8 is a graph showing the temperature change of the thermoluminescent sheet when the cassette according to the embodiment is used. FIG. 9 is a flowchart for explaining the operating procedure of the thermoluminescent sheet reading device according to the embodiment. FIG. 10 is a diagram for explaining an operation procedure for heating a thermoluminescent sheet by the thermoluminescent sheet reading device according to the embodiment.

Hereinafter, embodiments of the present invention will be described in detail using the drawings. Note that all of the embodiments described below are specific examples of the present invention. The numerical values, shapes, materials, components, arrangement positions and connection forms of the components, steps, order of steps, etc. shown in the following embodiments are merely examples, and do not limit the present invention. Therefore, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims representing the most significant concept of the present invention will be explained as arbitrary constituent elements.

Note that each figure is a schematic diagram and is not necessarily strictly illustrated. Therefore, for example, the scales and the like in each figure do not necessarily match. Furthermore, in each figure, substantially the same configurations are denoted by the same reference numerals, and overlapping explanations may be omitted or simplified.

Furthermore, in the following embodiments, expressions using "approximately" for approximately matching are used. For example, "approximately matching" does not only mean completely matching, but also substantially matching, that is, including a difference of, for example, several percent. The same applies to other expressions using "abbreviation" or expressions using "degree."

Furthermore, in this specification and the drawings, the X-axis, Y-axis, and Z-axis indicate three axes of a three-dimensional orthogonal coordinate system. In each embodiment, the Z-axis direction is the vertical direction, and the direction perpendicular to the Z-axis (direction parallel to the XY plane) is the horizontal direction. Note that the positive direction of the Z axis is vertically upward.

(Embodiment)
[overall structure]
First, the overall configuration of a thermoluminescent sheet reading device according to an embodiment will be described with reference to FIGS. 1 to 4.

FIG. 1 is a perspective view showing the front appearance of a thermoluminescent sheet reading device 1 according to an embodiment. FIG. 2 is a perspective view showing the appearance of the back side of the thermoluminescent sheet reading device 1 according to the embodiment. FIG. 3 is a perspective view showing the internal structure of the thermoluminescent sheet reading device 1 according to the embodiment. FIG. 4 is a block diagram showing a characteristic functional configuration of the thermoluminescent sheet reading device 1 according to the embodiment.

In addition, in FIG. 4, the air flow path is shown by a white arrow, and the movement of the cassette 31 is shown by a dashed-dotted arrow.

The thermoluminescent sheet reading device 1 is an example of a thermoluminescent sheet reading device in which the cassette 31 according to the embodiment is used. The thermoluminescent sheet reading device 1 is a device that heats a thermoluminescent sheet 60 containing a thermophosphor that has been irradiated with radiation or the like, and reads (measures) the two-dimensional distribution of fluorescence (thermofluorescence) emitted from the thermoluminescent sheet. be.

For example, an operator places the above-mentioned thermoluminescent sheet 60 on a plane where the distribution of radiation is desired to be confirmed. After irradiating the thermoluminescent sheet 60 with radiation, the operator reads the fluorescence using the thermoluminescent sheet reading device 1.

This allows the operator to confirm the two-dimensional distribution of fluorescence and the light intensity at each position. Therefore, the operator can confirm the distribution of radiation irradiation from the two-dimensional distribution of fluorescence.

Furthermore, if the correspondence between the amount of radiation irradiated to the thermophosphor and the amount of fluorescence emitted from the thermophosphor is known, the amount of radiation irradiated can be indirectly confirmed from the light intensity of the fluorescence.

When a thermophosphor is irradiated with radiation, some electrons are excited by the energy of the radiation, and this state is maintained. When a thermal phosphor is given external thermal energy (specifically, when heated) in a state in which electrons are excited, the electrons return to the ground state and fluorescence is emitted. The thermoluminescent sheet 60 is a thermoluminescent material uniformly formed on a sheet-like plane.

The thermoluminescent sheet reading device 1 includes an operation section 5, a control section 29, a storage section 30, a heating section 19, a heating chamber 27, an imaging section 15, a first cooling fan 14, and a second cooling fan 24. , a cooling chamber 22 , a transport section 36 , a housing 2 , and a cassette 31 .

The operation unit 5 is a user interface that accepts instructions from the operator. Specifically, the operation unit 5 is a device for an operator to instruct the operation of the thermoluminescent sheet reading device 1. The operation unit 5 is a device that accepts instructions such as setting the temperature of the heating unit 19 and measurement time when the imaging unit 15 reads thermofluorescence.

The operation unit 5 is, for example, a touch panel, a keyboard, buttons, or the like.

The control unit 29 is a processing unit that controls the operation of each component included in the thermoluminescent sheet reading device 1, such as the heating unit 19, the imaging unit 15, the transport unit 36, the first cooling fan 14, and the second cooling fan 24. .

The control unit 29 increases the temperature of the thermoluminescent sheet 60 at a temperature increase rate of 15° C./min or less. For example, the control unit 29 controls the heating unit 19 to raise the temperature of the heating unit 19 at a rate of 15°C/min or less, thereby raising the temperature of the thermoluminescent sheet 60 at a temperature increase rate of 15°C/min or less. The heating unit 19 is caused to heat the thermoluminescent sheet 60 as shown in FIG.

It is only necessary to raise the temperature of the thermoluminescent sheet 60 at a temperature increase rate of 15°C/min or less. The temperature of the thermoluminescent sheet 60 may be increased at a rate of temperature increase of less than 1 minute. Alternatively, the distance between the thermoluminescent sheet 60 and the heating section 19 may be controlled by the control section 29, so that the control section 29 may raise the temperature of the thermoluminescent sheet 60 at a temperature increase rate of 15° C./min or less.

In the present embodiment, after heating the heating unit 19 to a predetermined temperature, the control unit 29 brings the heating unit 19 into contact with the cassette 31 and heats the thermoluminescent sheet 60 held in the cassette 31 at a temperature of 15°C. Increase the temperature at a temperature increase rate of less than 1 minute.

Note that 15° C./min is, for example, one of the average value, median value, and maximum value per unit time. Further, a temperature change that instantaneously exceeds 15° C./min may be included, and in this case, 15° C./min is, for example, an average value per unit time.

Further, the control unit 29 raises the temperature of the thermoluminescent sheet 60 from 100° C. or lower to 200° C. or higher, for example, at a temperature increase rate of 15° C./min or lower.

Further, for example, the control unit 29 raises the temperature of the thermoluminescent sheet 60 to 100°C, and further raises the temperature of the thermoluminescent sheet 60 to 200°C or more at a temperature increase rate of 15°C/min or less. For example, the control unit 29 increases the temperature of the thermoluminescent sheet 60 from 100° C. to 200° C. or higher at a temperature increase rate of 15° C./min or less over 8 minutes or more.

Note that the control unit 29 controls the heating unit 19 so that the temperature of the thermoluminescent sheet 60 is increased at an average temperature increase rate of 15° C./min or less until the temperature of the thermoluminescent sheet 60 increases from 100° C. to 200° C. or higher. may be controlled. It is better if the control unit 29 controls the heating unit 19 to always raise the temperature of the thermoluminescent sheet 60 at a temperature increase rate of 15° C./min or less until the temperature of the thermoluminescent sheet 60 increases from 100° C. to 200° C. or higher. good. Further, the control unit 29 may heat the thermoluminescent sheet 60 from 100°C to 200°C or higher at a temperature increase rate of 15°C/min while changing the heat capacity of the heating unit 19. Specifically, for example, the control unit 29 heats the heating unit 19 and then brings it into contact with the unheated cassette 31 to heat the cassette 31. In this way, the control section 29 brings the heated heating section 19 into contact with the unheated cassette 31, thereby lowering the temperature of the heating section 19 a little while intentionally reducing the heat capacity of the heating section 19 once. Lower it. The control unit 29 may further heat the thermoluminescent sheet 60 by increasing the temperature of the heating unit 19 at a temperature increase rate of 15° C./min.

Furthermore, the control unit 29 controls the imaging unit 15 to cause the imaging unit 15 to read the two-dimensional distribution of fluorescence emitted from the heated thermoluminescent sheet 60.

Further, the control unit 29 controls the temperature of the first cooling fan 14, the second cooling fan 24, etc., for example, while heating the heating unit 19 and for an arbitrarily determined period of time after heating is stopped. A fan included in the fluorescent sheet reading device 1 is driven to cool the inside of the casing 2.

Further, the control unit 29 controls the transport unit 36 to move the cassette 31 placed in the heating chamber 27 to the cooling chamber 22 by the transport unit 36, for example.

The control unit 29 is realized by, for example, a CPU (Central Processing Unit) and a control program executed by the CPU.

The storage unit 30 is a storage device that stores control programs executed by the control unit 29, data, and the like.

The storage unit 30 stores, for example, temperature control conditions for the heating unit 19, image data acquired by the imaging unit 15, and the like. Here, the temperature control condition is a program (software) in which conditions for maintaining the temperature of the heating section 19 at a predetermined temperature for a predetermined period of time are set, and the control section 29 causes the heating section 19 to execute, e.g. , temperature control conditions such as increasing the temperature of the heating section 19 at a temperature increase rate of 15° C./min or less.

The storage unit 30 is realized by, for example, a ROM (Read Only Memory), a RAM (Random Access Memory), or the like.

The heating unit 19 is a heating device that heats the thermoluminescent sheet 60 in the heating chamber 27 into which the cassette 31 holding the thermoluminescent sheet 60 is carried. Specifically, the heating unit 19 heats the cassette 31 installed in the heating chamber 27 from above. More specifically, when heating the thermoluminescent sheet 60, the heating unit 19 comes into contact with the cassette 31 in which the thermoluminescent sheet 60 is installed, and heats the cassette 31. The heating unit 19 contacts the cassette 31 so that force is uniformly applied to the entire upper surface of the cassette 31.

In this embodiment, the thermoluminescent sheet reading device 1 includes a motor 28 for moving the heating section 19.

The motor 28 is a motor for moving the heating section 19. The control unit 29 drives the motor 28 to move the heating unit 19 closer to the cassette 31 installed in the heating chamber 27 when the heating unit 19 heats the thermoluminescent sheet 60 . Specifically, when the heating unit 19 performs heating, the control unit 29 drives the motor 28 to move the heating unit 19 so that the heating unit 19 presses the cassette 31 installed in the heating chamber 27. let On the other hand, when the heating section 19 does not heat the thermoluminescent sheet 60, the control section 29 drives the motor 28 to move the heating section 19 away from the cassette 31 installed in the heating chamber 27. Move 19.

The heating chamber 27 includes a thermoluminescent sheet 60 (more specifically, a thermoluminescent sheet 60 installed in the cassette 31 ) is the room (space) where it is installed. The thermoluminescent sheet 60 installed in the heating chamber 27 is heated by the heating section 19 and emits fluorescence.

The heating section 19 is, for example, a heater unit such as an electric heater.

The imaging unit 15 is an imaging device that reads fluorescence emitted from the thermoluminescent sheet 60. The imaging unit 15 includes, for example, a camera 15b having an image sensor that reads fluorescence, a lens 16 that collects fluorescence, and a device that transmits only a predetermined wavelength (more specifically, the wavelength of fluorescence emitted by the thermoluminescent sheet 60). A filter plate 17a provided with a filter 17.

The image sensor is, for example, a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor).

The filter 17 is an optical filter that transmits only light of a specific wavelength. Specifically, the filter 17 transmits the fluorescence emitted by the thermoluminescent sheet 60 and does not transmit other light.

This makes it difficult for light other than the fluorescence emitted by the thermoluminescent sheet 60 to enter the camera 15b. Therefore, the imaging unit 15 can accurately image (that is, read) the fluorescence emitted by the thermoluminescent sheet 60.

Note that the imaging unit 15 may include a shutter to control the timing of measuring fluorescence. Further, the imaging unit 15 may include a heat sink, a Peltier device, etc. in order to efficiently lower the temperature of the components of the imaging unit 15 (for example, the camera 15b).

The imaging unit 15 is installed in the housing 2, for example, below the heating unit 19 and supported by a holding plate 15a.

A through hole 21 that penetrates in the vertical direction (in the present embodiment, the Z-axis direction) is formed in the holding plate 15a.

Thereby, the air blown toward the imaging unit 15 by the first cooling fan 14 can be directed to the heating chamber 27 via the through hole 21 .

Further, the filter plate 17a and the camera 15b are fixed to the holding plate 15a so as to sandwich the lens 16 therebetween. Moreover, the space sandwiched between the two holding plates 15a communicates with the inspection window 4. This allows the operator to open the inspection window 4 and adjust the aperture of the lens 16.

Further, the holding plate 15a is provided with a bent portion 37 on the side of the through hole 21 from which air is exhausted.

The bent portion 37 is a mechanism for preventing air from directly flowing from one through hole 21 to another through hole 21 . The air that has passed through the through hole 21 collides with the bent portion 37. Thereby, more air within the housing 2 can be moved.

Further, the bent portion 37 is arranged above the through hole 21 .

Thereby, even if light from outside the housing 2 enters the housing 2 as stray light from the first cooling fan 14, for example, the amount of stray light that enters the camera 15b can be reduced.

Note that the through holes 21 may be arranged as far apart as possible. Thereby, more air within the housing 2 can be moved.

The first cooling fan 14 is an air blower that cools the inside of the casing 2 by blowing air into the thermoluminescent sheet reading device 1 from outside. The operation of the first cooling fan 14 is controlled by the control unit 29. In the present embodiment, the first cooling fan 14 is installed in the casing 2 adjacent to the imaging section 15 and takes air into the casing 2 from outside the casing 2 and blows it toward the imaging section 15. .

The second cooling fan 24 is a blower that discharges air from the inside of the thermoluminescent sheet reading device 1 to the outside. The operation of the second cooling fan 24 is controlled by the control unit 29. In this embodiment, the second cooling fan 24 is installed adjacent to the cooling chamber 22 and discharges the air from the cooling chamber 22 to the outside of the housing 2 .

Thereby, the second cooling fan 24 cools the thermoluminescent sheet 60 and the cassette 31 installed in the cooling chamber 22. Furthermore, the first cooling fan 14 and the second cooling fan 24 generate airflow flowing in a specific direction within the housing 2 to efficiently exhaust heat within the housing 2.

The thermoluminescent sheet 60 is installed in the cooling chamber 22 in order to cool down the thermoluminescent sheet 60 and the cassette 31 before the thermoluminescent sheet 60 and the cassette 31 whose fluorescence has been read are taken out of the housing 2. It is a room (space) where

Further, the heating chamber 27 and the cooling chamber 22 communicate with each other so that the cassette 31 can be moved. Of course, the heating chamber 27 and the cooling chamber 22 communicate with each other so that air can also be moved. Moreover, the heating chamber 27 and the cooling chamber 22 are arranged at the same height.

With the above configuration, an air flow path is formed in the thermoluminescent sheet reading device 1 in the direction of the white arrow shown in FIG. That is, air is taken into the housing 2 by the first cooling fan 14, passes near the imaging section 15, and further passes near the heating section 19. The air that has passed near the heating section 19 passes through the cooling chamber 22 and is discharged to the outside of the housing 2 by the second cooling fan 24 .

Thereby, the heat generated in the heating section 19 is prevented from being transmitted to the imaging section 15.

Note that the heating chamber 27 and the cooling chamber 22 may both be spaces in which the cassette 31 is installed within the housing 2, and the structures of these spaces are not particularly limited. For example, a wall may be provided to partition these spaces, or a door that can be opened and closed may be provided between these spaces.

The transport unit 36 is a mechanism that moves the cassette 31 from the heating chamber 27 to the cooling chamber 22. The transport unit 36 is arranged within the housing 2 so as to be movable within the housing 2 . The transport unit 36 is controlled by the control unit 29 and is driven to move the cassette 31 from the heating chamber 27 to the cooling chamber 22 .

The transport unit 36 includes, for example, a drivable cassette locking portion 36a (see FIG. 10) and a motor (not shown) for driving the cassette locking portion 36a.

The housing 2 is a box that covers a heating section 19 that heats the thermoluminescent sheet, an imaging section 15 that captures an image of fluorescence emitted from the thermoluminescent sheet 60, and the like.

The housing 2 is made of, for example, a metal material.

Note that in order to reduce stray light that enters into the housing 2 from outside the housing 2, it is preferable that the inner wall surface of the housing 2 has a low light reflectance. For example, a light absorbing material may be used for a wall surface arranged inside the housing 2. Alternatively, the wall surface may be painted with a light absorbing material.

The housing 2 includes door sections 3 and 3a, an inspection window 4, an air inlet 6, and an air outlet 12.

The door portion 3 is a door that can be opened and closed by an operator to carry the cassette 31 in which the thermoluminescent sheet 60 is installed into the heating chamber 27 within the housing 2 .

The air inlet 6 is a through hole provided in the casing 2 for introducing air into the casing 2 from outside. In this embodiment, the air inlet 6 is provided on the lower side of the casing 2 (for example, the surface of the casing 2 on the Y-axis direction side shown in FIG. 1).

As a result, air outside the casing 2 whose temperature is lower than that of the heating section 19 is drawn into the casing 2 from below the thermoluminescent sheet reading device 1 . Therefore, since the relatively high temperature air moves upward, the inside of the housing 2 can be efficiently exhausted.

The inspection window 4 is a translucent window that transmits visible light and is provided so as to communicate with a portion of the housing 2 where the lens 16 is installed. Providing the inspection window 4 in the housing 2 facilitates adjustment of the aperture of the imaging unit 15 (more specifically, the lens 16) when measuring fluorescence, maintenance of the imaging unit 15, and the like.

The air exhaust port 12 is a through hole provided in the housing 2 to discharge air inside the housing 2 to the outside. The air outlet 12 is arranged above the air inlet 6 (for example, on the Z-axis positive direction side in FIG. 2).

As a result, relatively high-temperature air moves upward, so that the inside of the housing 2 can be efficiently exhausted.

Note that the housing 2 may further include an upper ventilation port 11 in order to facilitate exhaustion of the inside of the housing 2.

The upper ventilation port 11 is a through hole formed in the casing 2 in order to exhaust the air in the heating chamber 27 to the outside of the casing 2 without passing through the cooling chamber 22.

The thermoluminescent sheet reading device 1 also includes a cassette storage section 7 for storing cassettes 31 for holding thermoluminescent sheets 60 that are not in use. The cassette storage section 7 is provided in the housing 2.

The cassette 31 is a box that holds the thermoluminescent sheet 60. The operator causes the cassette 31 to hold the thermoluminescent sheet 60 and places the cassette 31 into the casing 2 through the door 3. The specific configuration of the cassette 31 will be described later.

Further, the thermoluminescent sheet reading device 1 according to the present embodiment further includes an emergency stop switch 8, a cassette loading lamp 9a, a cassette loading lamp 9b, a heater energizing lamp 10, a power supply/connector section 13, and a light source 18. , a power supply unit 23 , an upper cooling fan 20 , and a power supply unit fan 25 .

The emergency stop switch 8 is a button for stopping the operation of the thermoluminescent sheet reading device 1 in an emergency. For example, when the emergency stop switch 8 is pressed by a worker, the control unit 29 forcibly stops the operation of each component of the thermoluminescent sheet reading device 1.

The cassette carry-in lamp 9a and the cassette carry-out lamp 9b visually notify the operator whether or not the cassette 31 can be carried into the housing 2 and the cassette 31 can be carried out from the housing 2 by turning on or off. This is a lamp for.

The heater energization lamp 10 is a lamp that visually informs the operator whether or not the heating section 19 is energized, that is, whether the heating section 19 is heating by turning on or off. .

The power supply/connector section 13 is a circuit composed of a power switch, a fuse, and the like. The power supply/connector section 13 is connected to, for example, a commercial AC power supply (not shown).

Further, the power supply/connector section 13 includes a connection terminal to which a communication cable or the like is connected, for example, when communicating with the outside via a network or the like. Thereby, the operator operates a PC (Personal Computer) etc. that is communicatively connected to the thermoluminescent sheet reading device 1 via a communication cable etc. to read the control program etc. stored in the storage unit 30. Change or retrieve data stored in the storage unit 30.

The light source 18 is an illumination light source for irradiating light onto the thermoluminescent sheet 60 when the thermoluminescent sheet 60 (more specifically, the cassette 31 in which the thermoluminescent sheet 60 is installed) is installed in the heating chamber 27. be.

For example, when the thermoluminescent sheet 60 is provided with a mark for position confirmation, the light source 18 emits light when the imaging unit 15 images the mark. More specifically, when capturing an image of the position confirmation mark, the control unit 29 controls the image capturing unit 15 to capture the image while causing the light source 18 to emit light.

As the light source 18, for example, an LED (Light Emitting Diode) or the like is used. The wavelength of the light used in the light source 18 is not particularly limited as long as it is a wavelength that passes through the filter 17.

The power supply unit 23 is a device that controls the power supplied from the power supply/connector section 13. The power supply unit 23 is a device that supplies power to each component of the thermoluminescent sheet reading device 1 , such as an electric heater, which is an example of the heating section 19 .

The upper cooling fan 20 is a fan for forming an air flow path within the housing 2 . The upper cooling fan 20 exhausts air inside the housing 2 to the outside or sends air outside the housing 2 into the interior in order to remove heat near the heating section 19 . The upper cooling fan 20 is arranged, for example, above the heating section 19 (on the positive side of the Z-axis in FIG. 3).

The power supply unit fan 25 is a fan for cooling the power supply unit 23. The power supply unit fan 25 is located near the power supply unit 23. In this embodiment, the power supply unit fan 25 is provided between the power supply unit 23 and the imaging section 15.

Thereby, the power supply unit fan 25 can blow air that has not been heated by the heating section 19 to the power supply unit 23 . Therefore, the power supply unit 23 can be effectively cooled.

[cassette]
Next, details of the cassette 31 according to the embodiment will be described with reference to FIGS. 5 to 8.

FIG. 5 is a perspective view showing the appearance of the cassette 31 according to the embodiment. Specifically, FIG. 5 is a perspective view showing the appearance of the cassette 31 according to the embodiment with the heat conductive sheet 40 closed. FIG. 6 is a perspective view showing the appearance of the thermally conductive sheet 40 in the opened state in the cassette 31 according to the embodiment. FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 5, showing the cassette 31 according to the embodiment.

Note that FIG. 6 shows a case where the protective sheet 61 and the thermoluminescent sheet 60 are not arranged on the cassette 31.

The cassette 31 is a box for holding the thermoluminescent sheet 60 when the thermoluminescent sheet 60 is carried into the thermoluminescent sheet reading device 1 . The cassette 31 includes a frame 34, a glass plate 35, a thermally conductive sheet 40, a spacer 43, and a protective sheet 61.

The frame body 34 is a frame that supports the glass plate 35, the heat conductive sheet 40, and the like. The frame body 34 supports the glass plate 35 and the thermally conductive sheet 40 so that the glass plate 35 and the thermally conductive sheet 40 can be switched between a state in which the thermoluminescent sheet 60 is sandwiched between the glass plate 35 and the thermally conductive sheet 40 (closed state) and a state in which they are not sandwiched (open state). do. In this embodiment, a protective sheet 61 is arranged between the thermoluminescent sheet 60 and the glass plate 35.

The cassette 31 is integrally formed by supporting a glass plate 35, a spacer 43, and a heat conductive sheet 40 with a frame 34. The thermally conductive sheet 40 is attached to the frame 34 via a hinge or the like so that it can be switched between a state in which the thermoluminescent sheet 60 is sandwiched together with the glass plate 35 and a state in which it is not sandwiched.

The material of the frame 34 is not particularly limited, and may be, for example, resin or metal.

Further, the upper surface of the spacer 43 and the upper surface of the thermoluminescent sheet 60 are arranged on the glass plate 35 so that they are flush with each other. As a result, the lower surface of the thermally conductive sheet 40 comes into contact with the thermoluminescent sheet 60 by applying a uniform force to the entire surface of the thermoluminescent sheet 60.

Further, the upper surface 50 of the frame 34 and the upper surface 50a of the thermally conductive sheet 40 are formed to be flush with each other.

Thereby, when transmitting the heat of the heating section 19 to the thermoluminescent sheet 60 via the heat conductive sheet 40, it becomes easier to conduct the heat uniformly to the entire thermoluminescent sheet 60. Therefore, the thermoluminescent sheet 60 is less likely to be deformed such as warping.

Further, the frame body 34 includes a plurality of grooves 32 on the upper surface 50.

The groove portion 32 is a portion that is locked by a cassette locking portion 36a (see FIG. 10) provided in the conveyance portion 36 when the cassette 31 is conveyed from the heating chamber 27 to the cooling chamber 22, and is formed at multiple locations. ing.

Note that the groove portion 32 may have any structure as long as it is locked to the cassette locking portion 36a provided in the conveying portion 36, and is not particularly limited, such as a depression, a through hole, or the like.

Further, the cassette 31 may be formed with a depression, a hole, etc. for the operator to grasp so that the operator can easily handle the cassette 31.

The glass plate 35 is a heat-resistant glass having translucency that allows fluorescence emitted from the thermoluminescent sheet 60 to pass therethrough. When the imaging unit 15 reads the fluorescence emitted from the thermoluminescent sheet 60, the thermoluminescent sheet 60 is heated. At this time, the glass plate 35 is also heated, so it is preferable that the glass plate 35 is made of glass that has a low coefficient of thermal expansion and is tempered so as not to break due to temperature changes.

The glass plate 35 is made of silicon dioxide and boron oxide, for example. The glass plate 35 is located between the thermoluminescent sheet 60 and the imaging section 15 when the cassette 31 is placed in the heating chamber 27.

The thermally conductive sheet 40 is a plate for pressing the thermoluminescent sheet 60 onto the glass plate 35 from above. Specifically, the thermally conductive sheet 40 is a member that is located between the heating section 19 and the thermoluminescent sheet 60 and is directly pressed against the heating section 19 when heating the cassette 31. For example, the control unit 29 drives the motor 28 to bring the heating unit 19 into contact with the heat conductive sheet 40 to heat the thermoluminescent sheet 60 via the heat conductive sheet 40.

The thermally conductive sheet 40 suppresses the thermoluminescent sheet 60 from warping due to heating, and also suppresses the thermoluminescent sheet 60 from coming into contact with the heating section 19 and being welded.

Further, it is preferable that the thermally conductive sheet 40 be made of a material with low thermal conductivity that conducts the heat of the heating section 19 to the thermoluminescent sheet 60. Further, it is preferable that the thermally conductive sheet 40 be made of a material that is not easily deformed by heat.

For example, the material used for the thermally conductive sheet 40 is a material (so-called Teflon mesh) composed of glass fiber and polytetrafluoroethylene (so-called Teflon (registered trademark)), Teflon, or fluororubber. In particular, the material used for the thermally conductive sheet 40 is preferably polytetrafluoroethylene or fluororubber, for example, from the viewpoint of thermal conductivity.

Further, the thickness of the heat conductive sheet 40 is preferably formed to be, for example, 0.5 mm or more.

FIG. 8 is a graph showing the temperature change of the thermoluminescent sheet 60 when the cassette 31 according to the embodiment is used. The graph shown in FIG. 8 shows the temperature change of the thermoluminescent sheet 60 with respect to the elapsed time, and the solid line shows the temperature change of the thermoluminescent sheet 60 held in the cassette 31 according to the example, and The temperature change of the thermoluminescent sheet 60 held at the temperature is shown by a broken line.

The cassette 31 according to the embodiment employs a thermally conductive sheet 40 made of Teflon and having a thickness of 1 mm. In addition, the cassette according to the comparative example is made of a material (so-called Teflon mesh) composed of glass fiber and polytetrafluoroethylene (so-called Teflon (registered trademark)), and has a thickness of 0.08 mm. Seat 40 is adopted. The cassette 31 according to the example and the cassette according to the comparative example differ only in the configuration of the thermally conductive sheet 40.

In addition, the temperature change shown in FIG. 8 is exemplified in the example when the heating section 19 is set at 225°C and brought into contact with the thermally conductive sheet 40, and in the comparative example, the heating section 19 is set at 200°C. A case is illustrated in which the heat conductive sheet 40 is brought into contact with the heat conductive sheet 40. Furthermore, a rapid rise in temperature was observed in all cases about 40 seconds after the start of the measurement. This timing is the timing at which the heating section 19 comes into contact with the cassette 31.

The temperature of the thermoluminescent sheet 60 held in the cassette 31 according to the embodiment rapidly rises to about 100°C. Moreover, the temperature of the thermoluminescent sheet 60 held in the cassette 31 according to the example increases to about 200° C. about 600 seconds after the start of the measurement. In this way, the temperature of the thermoluminescent sheet 60 held in the cassette 31 according to the embodiment increases from 100° C. to 200° C. over about 9 minutes at an average rate of about 10° C./min.

On the other hand, the temperature of the thermoluminescent sheet 60 held in the cassette according to the comparative example rapidly rises to about 160°C. Further, the temperature of the thermoluminescent sheet 60 held in the cassette according to the comparative example rises to about 200° C. about 300 seconds after starting the measurement. In this way, the temperature of the thermoluminescent sheet 60 held in the cassette according to the comparative example increases from 100° C. to 200° C. over about 4 minutes at an average rate of about 23° C./min.

Here, no air bubbles were generated from the thermoluminescent sheet 60 held in the cassette 31 according to the example. On the other hand, bubbles were generated from the thermoluminescent sheet 60 held in the cassette according to the comparative example.

This is considered to be because the components for holding the thermophosphor, such as toluene, contained in the thermoluminescent sheet 60 were rapidly vaporized due to the rapid temperature rise of the thermoluminescent sheet 60.

As described above, the inventors of the present invention have discovered that by appropriately controlling the temperature rise of the thermoluminescent sheet 60, the generation of bubbles in the thermoluminescent sheet 60 can be suppressed, that is, the deformation of the thermoluminescent sheet 60 can be suppressed. Ta.

Note that in the cassette 31 according to the example, the heat conductive sheet 40 having a thickness of 1 mm was used, but the thickness of the heat conductive sheet 40 may be any thickness that suppresses deformation (occurrence of bubbles) of the thermoluminescent sheet 60. . For example, the thickness of the heat conductive sheet 40 is preferably 0.5 mm or more. Further, for example, it is better if the thickness of the heat conductive sheet 40 is formed to be 0.9 mm or more. Further, for example, it is better if the thickness of the heat conductive sheet 40 is 1 mm or more. In this way, the thickness of the thermally conductive sheet 40 is preferably thicker from the viewpoint of suppressing deformation of the thermoluminescent sheet 60.

For example, the heat conductive sheet 40 may include a light absorbing agent that can absorb light in order to absorb the light that is diffusely reflected by the fluorescence emitted from the thermo fluorescent sheet 60 between the thermo fluorescent sheet 60 and the heat conductive sheet 40. It would be good if it included. When the diffusely reflected fluorescence enters the imaging unit 15 (more specifically, the camera 15b), it becomes noise when the thermoluminescent sheet reading device 1 reads the fluorescence emitted from the thermoluminescent sheet 60. Therefore, the heat conductive sheet 40 is preferably black, for example. The heat conductive sheet 40 is blackened by containing carbon, for example.

The spacer 43 is a member placed on the glass plate 35 together with the thermoluminescent sheet 60. When the spacer 43 is placed on the glass plate 35, it is placed so as to surround the thermoluminescent sheet 60. The thermoluminescent sheet 60 is placed between the glass plate 35 and the thermally conductive sheet 40.

The spacer 43 is fixed to the frame body 34 by a spacer locking portion 44 . Here, the spacer locking portion 44 is constituted by a member such as a screw that is removable from the frame 34, for example. That is, the spacer 43 is fixed to the frame 34 so as to be removably attached to the frame 34.

By doing so, the operator can use the cassette 31 while appropriately selecting the optimal thickness of the spacer 43 according to the thickness of the thermoluminescent sheet 60.

Although the material of the spacer 43 is not particularly limited, it is, for example, aluminum.

The protective sheet 61 is a translucent sheet that transmits the fluorescence emitted from the thermoluminescent sheet 60. Furthermore, when measuring the fluorescence emitted from the thermoluminescent sheet 60, it is necessary to heat the thermoluminescent sheet 60, and the protective sheet 61 is also heated at that time. It is good to have a low expansion coefficient and heat resistance.

The protective sheet 61 is made of, for example, polyethylene terephthalate (PET), polyimide, or the like. The protective sheet 61 is placed between the thermoluminescent sheet 60 and the glass plate 35.

Here, the thickness of the spacer 43 and the total thickness of the thermoluminescent sheet 60 and the protective sheet 61 substantially match. In other words, the upper surface of the spacer 43 is substantially flush with the upper surface of the thermoluminescent sheet 60. That is, the spacer 43 and the thermoluminescent sheet 60 are arranged on the glass plate 35 so that the upper surface of the spacer 43 and the upper surface of the thermoluminescent sheet 60 are flush with each other.

This makes it easier for the thermally conductive sheet 40 to apply uniform force to the entire thermoluminescent sheet 60. Furthermore, when the heat conductive sheet 40 conducts heat to the thermoluminescent sheet 60, heat is easily applied to the entire thermoluminescent sheet 60 uniformly. Therefore, deformation of the thermoluminescent sheet 60 is further suppressed.

[Operating procedure]
Next, the operating procedure of the thermoluminescent sheet reading device 1 will be explained with reference to FIGS. 9 and 10.

FIG. 9 is a flowchart for explaining the operating procedure of the thermoluminescent sheet reading device 1 according to the embodiment. FIG. 10 is a diagram for explaining an operation procedure for heating the thermoluminescent sheet 60 by the thermoluminescent sheet reading device 1 according to the embodiment.

First, the operator places the thermoluminescent sheet 60 on the cassette 31 (step S101). Specifically, the operator places the thermoluminescent sheet 60 on the protective sheet 61 placed on the glass plate 35 of the cassette 31.

Next, the operator places the thermally conductive sheet 40 on the thermoluminescent sheet 60 (step S102). Specifically, by placing the thermally conductive sheet 40 on the thermoluminescent sheet 60, the operator changes the cassette 31 from the open state to the closed state and causes the cassette 31 to hold the thermoluminescent sheet 60.

Next, the operator opens the door 3, places the cassette 31 holding the thermoluminescent sheet 60 in steps S101 and S102 in the heating chamber 27, and closes the door 3 (step S103).

For example, by executing steps S101 to S103, the operator can change the thermal fluorescent sheet shown in FIG. 10(b) from the state in which the cassette 31 is not installed in the heating chamber 27 shown in FIG. The cassette 31 holding the cassette 60 is carried into the heating chamber 27 through the carry-in port 38 and placed in the heating chamber 27.

Next, the control unit 29 controls the heating unit 19 to start heating the heating unit 19 (step S104).

Note that, for example, at this time, the control unit 29 drives the fans included in the thermoluminescent sheet reading device 1 , such as the first cooling fan 14 and the second cooling fan 24 , to generate an airflow within the casing 2 .

As a result, an air flow path is formed inside the thermoluminescent sheet reading device 1.

Next, the control unit 29 causes the heating unit 19 to contact the thermally conductive sheet 40 by driving the motor 28 so that the heating unit 19 comes into contact with the upper part of the cassette 31 disposed in the heating chamber 27 (step S105). In step S105, as shown in FIG. 10(c), the control unit 29 drives the motor 28 so that the heating unit 19 contacts the top surface of the cassette 31 (more specifically, the heat conductive sheet 40). let In this manner, the control unit 29 heats the thermoluminescent sheet 60 via the heat conductive sheet 40 by bringing the heating unit 19 into contact with the heat conductive sheet 40 .

Next, the control unit 29 causes the imaging unit 15 (specifically, the camera 15b) to read the fluorescence emitted from the thermoluminescent sheet 60 by starting the exposure of the imaging unit 15 (specifically, the camera 15b). (step S106).

Note that the timing at which the control unit 29 executes step S104 and step S106 may be arbitrarily determined. For example, the control unit 29 may execute step S104 when the operator's instruction is received through the operation unit 5. Alternatively, the control unit 29 can control whether the door 3 is in the closed state by, for example, using a sensor (not shown) that detects the open/closed state of the door 3 and a sensor (not shown) that detects that the cassette 31 is placed in the heating chamber 27. If it is detected that the cassette 31 is present and that the cassette 31 is placed in the heating chamber 27, step S104 may be executed. Alternatively, the control unit 29 may execute step S104 after step S105. Further, the control unit 29 may execute step S106 at the same time as executing step S104. Alternatively, the control unit 29 may execute step S106 after step S104, and then execute step S105.

In this way, the order of steps executed by the control unit 29 may be changed as appropriate.

Next, the control unit 29 controls the heating unit 19 to raise the temperature of the thermoluminescent sheet 60 to 100° C. (step S107). In step S107, the temperature increase rate may be set arbitrarily and is not particularly limited. In this embodiment, the temperature increase rate is higher than 15° C./min in step S107. Thereby, the time to read the fluorescence emitted from the thermoluminescent sheet 60 can be shortened without deforming the thermoluminescent sheet 60.

Next, the control unit 29 raises the temperature of the heating unit 19 to 200°C over 8 minutes or more at a temperature increase rate of 15°C/min or less (step S108).

Next, the control unit 29 maintains the temperature at 200° C. for a predetermined period of time (step S109). The predetermined time may be arbitrarily determined in advance and is not particularly limited. The predetermined time may be, for example, 15 minutes, 30 minutes, or 1 hour.

As the controller 29 executes steps S107 to S109, the temperature of the thermoluminescent sheet 60 gradually increases. At the same time, the thermoluminescent sheet 60 emits fluorescence, and the imaging section 15 reads the fluorescence. In this embodiment, the control unit 29 controls the heating unit 19 to heat the heating unit 19 to 225° C., and further controls the motor 28 to apply the heating unit 19 to the heat conductive sheet 40 for a predetermined period of time. By making contact, steps S107 to S109 are realized.

Note that in this embodiment, the imaging unit 15 reads the integrated value of fluorescence emitted from the thermoluminescent sheet 60. For example, the control unit 29 may cause the imaging unit 15 to read fluorescence at an arbitrary temperature by exposing the imaging unit 15 to light at an arbitrary timing from step S104 to step S109.

Next, after a predetermined period of time has elapsed, the control unit 29 causes the imaging unit 15 to stop reading the fluorescence and controls the transport unit 36 to transfer the cassette 31 from the heating chamber 27 to the cooling room. 22 (step S110).

In step S109, as shown in FIG. 10(d), the control section 29 first moves the heating section 19 upward by the motor 28 so as to return it to the state shown in FIG. 10(a), for example. After that, the control unit 29 causes the transport unit 36 to transport the cassette 31 from the heating chamber 27 to the cooling chamber 22 . For example, the control unit 29 moves the transport unit 36 so as to approach the heating chamber 27, and temporarily stops it when it approaches the cassette 31 installed in the heating chamber 27. Further, the control section 29 drives the cassette locking section 36a to lock the cassette 31 in, for example, the groove 32 shown in FIG. 5, and moves the transport section 36 to the cooling chamber 22.

Note that in step S110, the control unit 29 may or may not stop heating the heating unit 19. By continuing to heat the heating unit 19, the operator can immediately read the fluorescence of another thermoluminescent sheet 60.

Next, the operator opens the door 3a at an arbitrary timing and takes out the cassette 31 from the cooling chamber 22 (step S111).

(Effects, etc.)
As explained above, the thermoluminescent sheet reading method according to one aspect of the present invention is a thermoluminescent sheet reading method that reads the two-dimensional distribution of fluorescence emitted from the thermoluminescent sheet 60, and is a thermoluminescent sheet reading method that reads the two-dimensional distribution of fluorescence emitted from the thermoluminescent sheet 60, and is The method includes a heating step of heating the thermoluminescent sheet 60 at an increasing rate, and an imaging step of reading the fluorescence emitted from the thermoluminescent sheet 60 heated in the heating step.

According to this, rapid heating of the thermoluminescent sheet 60 is suppressed. In particular, when the thermoluminescent sheet 60 contains volatile substances such as toluene, there is a possibility that the thermoluminescent sheet 60 will suddenly vaporize due to a sudden temperature rise. When such a substance suddenly vaporizes, bubbles are generated in the thermoluminescent sheet 60, causing it to deform. Therefore, by increasing the temperature of the thermoluminescent sheet 60 at a temperature increase rate of 15° C./min or less, rapid vaporization of such substances is suppressed. Thereby, deformation of the thermoluminescent sheet 60 is suppressed.

Further, for example, in the heating step, the temperature of the thermoluminescent sheet 60 is increased from 100° C. or lower to 200° C. or higher at a temperature increase rate of 15° C./min or lower.

According to this, a rapid temperature rise of the thermoluminescent sheet 60 is suppressed in a high temperature state. Therefore, deformation of the thermoluminescent sheet 60 is further suppressed.

For example, the heating step includes a first heating step of raising the temperature of the thermoluminescent sheet 60 to 100° C., and after the first heating step, raising the temperature of the thermoluminescent sheet 60 to 200° C. or higher at a temperature increase rate of 15° C./min or less. a second heating step of increasing the temperature to .

It is considered that the lower the rate of temperature rise of the thermoluminescent sheet 60, the more difficult the thermoluminescent sheet 60 is to deform. However, the lower the rate of temperature rise of the thermoluminescent sheet 60, the more time is required to read the fluorescence emitted from the thermoluminescent sheet 60. Therefore, heating is performed at a rate of 15° C./min or less, particularly at a high temperature of about 100° C. to 200° C., where volatile substances such as toluene are easily vaporized rapidly. Thereby, deformation of the thermoluminescent sheet 60 can be suppressed, and the time taken to read the fluorescence can be suppressed from increasing.

Further, for example, in the second heating step, the temperature of the thermoluminescent sheet 60 is increased over 8 minutes or more so that the temperature of the thermoluminescent sheet 60 is 200° C. or higher.

According to this, in a high temperature state, a rapid temperature rise of the thermoluminescent sheet 60 is further suppressed. Therefore, deformation of the thermoluminescent sheet 60 is further suppressed.

Further, for example, the thermoluminescent sheet reading method according to one aspect of the present invention further includes a placing step of placing the thermally conductive sheet 40 on the thermoluminescent sheet 60. In this case, in the heating step, the heating section 19 is brought into contact with the thermally conductive sheet 40 and the thermoluminescent sheet 60 is heated by the heating section 19 via the thermally conductive sheet 40 .

According to this, since the thermoluminescent sheet 60 is heated by the heating section 19 via the thermally conductive sheet 40, by suitably selecting the thickness, material, etc. of the thermally conductive sheet 40, an appropriate amount of time can be obtained. The thermoluminescent sheet 60 can be heated so that the temperature changes. Therefore, deformation of the thermoluminescent sheet 60 is further suppressed.

Further, for example, the thickness of the heat conductive sheet 40 is 0.5 mm or more.

According to this, it becomes easier to suppress a sudden temperature rise of the thermoluminescent sheet 60 by the thermally conductive sheet 40, and therefore it becomes easier to heat the thermoluminescent sheet 60 so that the temperature changes appropriately over time. Therefore, deformation of the thermoluminescent sheet 60 is further suppressed.

Further, for example, the material of the heat conductive sheet 40 is polytetrafluoroethylene or fluororubber.

These materials have lower thermal conductivity than, for example, aluminum, which is widely used for the thermally conductive sheet 40, and are less likely to be deformed by heat. Therefore, by using these materials for the heat conductive sheet 40, the thermoluminescent sheet 60 can be heated so that the temperature changes appropriately over time, and the heat conductive sheet 40 can be made difficult to deform due to heat.

Further, for example, the heat conductive sheet 40 is black.

According to this, the light diffusely reflected from the fluorescent light emitted by the thermoluminescent sheet 60 is absorbed by the thermally conductive sheet 40. This makes it difficult for such diffusely reflected light to enter the camera 15b included in the imaging section 15 that reads the fluorescence emitted from the thermoluminescent sheet 60, so that the accuracy of reading fluorescence in the imaging section 15 is improved.

Further, the cassette 31 according to one aspect of the present invention includes a glass plate 35 having a translucent property that transmits fluorescence emitted from the thermoluminescent sheet 60, a thermally conductive sheet 40 having a thickness of 0.5 mm or more, and a glass plate 35. 35 and a heat conductive sheet 40, the frame body 34 supports the glass plate 35 and the heat conductive sheet 40 so as to be switchable between a state in which the thermoluminescent sheet 60 is sandwiched between the glass plate 35 and the heat conductive sheet 40, and a state in which the thermoluminescent sheet 60 is not sandwiched between the glass plate 35 and the heat conductive sheet 40.

According to such a configuration, the thermoluminescent sheet 60 can be heated via the heat conductive sheet 40. In particular, by setting the thickness of the heat conductive sheet 40 to 0.5 mm or more, the thermoluminescent sheet 60 can be heated so that the temperature changes appropriately over time. Therefore, deformation of the thermoluminescent sheet 60 is suppressed.

Further, the thermoluminescent sheet reading device 1 according to one aspect of the present invention includes a cassette 31, a heating unit 19 that contacts the thermally conductive sheet 40 and heats the thermoluminescent sheet 60 via the thermally conductive sheet 40, and a thermoluminescent sheet reader 1. It includes an imaging unit 15 that reads fluorescence emitted from the sheet 60.

According to this, the thermoluminescent sheet 60 can be heated via the heat conductive sheet 40 included in the cassette 31. In particular, when the thickness of the thermally conductive sheet 40 is 0.5 mm or more, the thermoluminescent sheet 60 can be heated so that the temperature changes appropriately over time. Therefore, deformation of the thermoluminescent sheet 60 is suppressed.

(Other embodiments)
Although the thermoluminescent sheet reading method and the like according to the present invention have been described above based on the embodiments, the present invention is not limited to the above embodiments.

For example, the heating section 19 is not particularly limited as long as it has a shape that can uniformly press the top surface of the cassette 31. For example, the lower surface of the heating section 19 may have a portion in contact with the cassette 31 other than the surface in contact with the cassette 31. Specifically, the heating unit 19 may be provided at a plurality of locations in contact with the ends (corners) of the upper surface of the cassette 31 . By doing so, when the heating section 19 presses the cassette 31, the position of the cassette 31 can be fixed by the plurality of contact points. Therefore, variations in the position of the cassette 31 within the heating chamber 27 are suppressed each time the thermofluorescence is read.

Further, for example, in the present embodiment, the shape of the cassette 31 is approximately square when viewed from above, but the shape is not limited to this. The top view shape of the cassette 31 may be a rectangle, such as a rectangle, or may be another shape, such as a circle.

Further, for example, the control unit 29 may be configured with dedicated hardware, or may be realized by executing a software program suitable for each component. The control unit 29 may be realized by a program execution unit such as a CPU or a processor reading and executing a software program recorded on a recording medium such as a hard disk or a semiconductor memory.

Note that the present invention can be realized not only as a thermoluminescent sheet reading device 1, but also as a program including, as steps, the processes performed by each component of the thermoluminescent sheet reading device 1, and a computer-readable DVD (on which the program is recorded). It can also be realized as a recording medium such as a Digital Versatile Disc.

That is, the general or specific aspects described above may be realized in a system, a device, an integrated circuit, a computer program, or a computer-readable recording medium, and any of the systems, devices, integrated circuits, computer programs, and recording media may be implemented. It may be realized by any combination.

In addition, forms obtained by applying various modifications to each embodiment that those skilled in the art can think of, or by arbitrarily combining the constituent elements and functions of each embodiment without departing from the spirit of the present invention. The form is also included in the present invention.

INDUSTRIAL APPLICATION This invention is applicable to a thermoluminescent sheet reading device which can suppress deformation|transformation of a thermoluminescent sheet as a device which reads the fluorescence emitted from a thermoluminescent sheet, for example.

1 Thermoluminescent sheet reading device 2 Housing 3, 3a Door section 4 Inspection window 5 Operation section 6 Air inlet 7 Cassette storage section 8 Emergency stop switch 9a Cassette loading lamp 9b Cassette loading lamp 10 Heater energizing lamp 11 Upper ventilation opening 12 Air Discharge port 13 Power supply/connector section 14 First cooling fan 15 Imaging section 15a Holding plate 15b Camera 16 Lens 17 Filter 17a Filter plate 18 Light source 19 Heating section 20 Upper cooling fan 21 Through hole 22 Cooling chamber 23 Power supply unit 24 Second cooling fan 25 Power supply unit fan 27 Heating chamber 28 Motor 29 Control section 30 Storage section 31 Cassette 32 Groove section 34 Frame 35 Glass plate 36 Conveyance section 36a Cassette locking section 37 Bend section 38 Carrying inlet 40 Thermal conductive sheet 43 Spacer 44 Spacer locking Part 50, 50a Top surface 60 Thermoluminescent sheet 61 Protective sheet

Claims (6)

A thermoluminescent sheet reading method for reading a two-dimensional distribution of fluorescence emitted from a thermoluminescent sheet,
a placing step of placing a thermally conductive sheet on the thermoluminescent sheet;
a heating step of heating the thermoluminescent sheet at a temperature increase rate of 15° C./min or less;
an imaging step of reading fluorescence emitted from the thermoluminescent sheet heated in the heating step,
In the heating step, a heating section is brought into contact with the thermally conductive sheet, and the thermoluminescent sheet is heated by the heating section via the thermally conductive sheet,
The material of the thermally conductive sheet is polytetrafluoroethylene or fluororubber,
The heating step includes:
a first heating step of raising the temperature of the thermoluminescent sheet to 100°C;
After the first heating step, a second heating step of increasing the temperature of the thermoluminescent sheet to 200° C. or more at a temperature increase rate of 15° C./min or less,
In the first heating step, the temperature of the thermoluminescent sheet is increased to 100°C at a temperature increase rate higher than 15°C/min.
How to read thermoluminescent sheets. The thermoluminescent sheet reading method according to claim 1 , wherein in the second heating step, the temperature of the thermoluminescent sheet is increased over 8 minutes or more so that the temperature of the thermoluminescent sheet becomes 200° C. or higher. The thermoluminescent sheet reading method according to claim 1 or 2 , wherein the thermally conductive sheet has a thickness of 0.5 mm or more. The thermoluminescent sheet reading method according to any one of claims 1 to 3 , wherein the thermally conductive sheet is black. a glass plate having translucency that transmits the fluorescence emitted from the thermoluminescent sheet; a thermally conductive sheet having a thickness of 0.5 mm or more; and a state in which the thermoluminescent sheet is sandwiched between the glass plate and the thermally conductive sheet. a frame body that supports the glass plate and the thermally conductive sheet so as to be switchable between a state in which they are not sandwiched, and a cassette in which the material of the thermally conductive sheet is polytetrafluoroethylene or fluororubber;
a heating unit that comes into contact with the thermally conductive sheet and heats the thermoluminescent sheet via the thermally conductive sheet;
an imaging unit that reads fluorescence emitted from the thermoluminescent sheet ,
The heating section is
a first heating step of raising the temperature of the thermoluminescent sheet to 100°C;
After the first heating step, perform a second heating step of increasing the temperature of the thermoluminescent sheet to 200° C. or more at a temperature increase rate of 15° C./min or less,
In the first heating step, the temperature of the thermoluminescent sheet is increased to 100°C at a temperature increase rate higher than 15°C/min.
Thermoluminescent sheet reader. The thermoluminescent sheet reading device according to claim 5 , wherein the thermally conductive sheet is black.

Images