Radiation detection device, control method, and computer program

Abstract

Provided are a radiation detection device, a control method, and a computer program capable of appropriately adjusting the temperature of a radiation detection element.　The radiation detection device comprises: a sample chamber inside which a sample is disposed; a radiation detection element that is disposed inside the sample chamber and is for detecting radiation generated from the sample; an atmosphere adjustment unit that adjusts the atmosphere inside the sample chamber to either a state in which the inside of the sample chamber is depressurized or a state in which a predetermined gas is introduced into the sample chamber; a temperature adjustment unit that adjusts the temperature of the radiation detection element; and a control unit. When the atmosphere adjustment unit adjusts the atmosphere inside the sample chamber to the state in which the predetermined gas is introduced, the control unit causes the temperature adjustment unit to adjust the temperature of the radiation detection element to a higher temperature than when the atmosphere adjustment unit adjusts the atmosphere inside the sample chamber to the state in which the inside of the sample chamber is depressurized.

Description

Radiation detection device, control method, and computer program

[0001] The present invention relates to a radiation detection device, a control method, and a computer program for detecting radiation.

[0002] Radiation detection, which detects radiation emitted from a sample, is often performed in a reduced pressure atmosphere to improve detection sensitivity. Some samples are undesirable for placement in a reduced pressure atmosphere, such as powders that may scatter under reduced pressure, samples containing water, samples that cannot be dried, or samples that expand and burst in a reduced pressure atmosphere (e.g., biological samples). To enable highly sensitive radiation detection for such samples, a specific gas, such as helium, which absorbs radiation less than air, may be introduced into the sample chamber. Patent Document 1 discloses a radiation detection device that introduces helium into the sample chamber.

[0003] Patent No. 5874613

[0004] Some radiation detectors include a radiation detection element using a semiconductor. To increase the radiation detection sensitivity, the radiation detection element is often used in a cooled state. Because the thermal conductivity of gases such as helium is higher than that of a reduced-pressure atmosphere, a large amount of heat flows into the radiation detection element from the outside during cooling in a specific gas. Therefore, high cooling performance is required to cool the radiation detection element in a specific gas to a temperature at which it can be cooled in a reduced-pressure atmosphere. If the temperature of the radiation detection element is adjusted to a temperature at which it can be cooled in a specific gas, it is not possible to increase the detection sensitivity when detecting radiation in a reduced-pressure atmosphere.

[0005] The present invention has been made in consideration of the above circumstances, and its object is to provide a radiation detection device, a control method, and a computer program that can appropriately adjust the temperature of a radiation detection element.

[0006] A radiation detection device according to one aspect of the present invention comprises a sample chamber in which a sample is placed, a radiation detection element placed in the sample chamber for detecting radiation emitted from the sample, an atmosphere adjustment unit that adjusts the atmosphere inside the sample chamber to one of a state in which the interior of the sample chamber is reduced in pressure and a state in which a predetermined gas is introduced into the interior of the sample chamber, a temperature adjustment unit that adjusts the temperature of the radiation detection element, and a control unit, wherein when the atmosphere adjustment unit adjusts the atmosphere inside the sample chamber to a state in which the predetermined gas is introduced, the control unit causes the temperature adjustment unit to adjust the temperature of the radiation detection element to a higher temperature than when the atmosphere adjustment unit adjusts the atmosphere inside the sample chamber to a state in which the interior of the sample chamber is reduced in pressure.

[0007] In one aspect of the present invention, a radiation detection device adjusts the atmosphere inside a sample chamber to one of two states: a state in which the inside of the sample chamber is depressurized, and a state in which a predetermined gas is introduced into the sample chamber. The radiation detection device adjusts the temperature of the radiation detection element when the predetermined gas is introduced into the sample chamber to a temperature higher than the temperature when the inside of the sample chamber is depressurized. When the predetermined gas is introduced into the sample chamber, the radiation detection element is less likely to be cooled than when the inside of the sample chamber is depressurized. However, by adjusting the temperature of the radiation detection element to a temperature higher than when the inside of the sample chamber is depressurized, it becomes possible to appropriately adjust the temperature of the radiation detection element even when the predetermined gas is introduced into the sample chamber.

[0008] In one form of the radiation detection device of the present invention, the control unit receives an instruction to adjust the atmosphere inside the sample chamber to either a state where the inside of the sample chamber is depressurized or a state where the specified gas is introduced into the sample chamber, and when receiving an instruction to adjust the atmosphere inside the sample chamber to a state where the inside of the sample chamber is depressurized, the control unit sets the target value of the temperature of the radiation detection element to be adjusted by the temperature adjustment unit to a specified first temperature, and when receiving an instruction to adjust the atmosphere inside the sample chamber to a state where the specified gas is introduced into the sample chamber, the control unit sets the target value of the temperature of the radiation detection element to be adjusted by the temperature adjustment unit to a specified second temperature which is higher than the first temperature.

[0009] In one aspect of the present invention, when a radiation detection device receives an instruction to adjust the atmosphere inside the sample chamber to a reduced pressure state, the radiation detection device sets a target value of the temperature of the radiation detection element to be adjusted to a predetermined first temperature. Also, when a radiation detection device receives an instruction to adjust the atmosphere inside the sample chamber to a state in which a predetermined gas has been introduced into the sample chamber, the radiation detection device sets a target value of the temperature of the radiation detection element to be adjusted to a predetermined second temperature higher than the first temperature. Therefore, the radiation detection device adjusts the radiation detection element to the first temperature when the inside of the sample chamber is reduced pressure, and adjusts the radiation detection element to the second temperature higher than the first temperature when the predetermined gas has been introduced into the sample chamber.

[0010] A radiation detection device according to one embodiment of the present invention further includes a signal processing unit that determines the intensity of a signal generated in response to radiation incident on the radiation detection element, and the control unit adjusts the value of a parameter of the signal processing unit to a value corresponding to the temperature of the radiation detection element to be adjusted by the temperature adjustment unit.

[0011] In one aspect of the present invention, a radiation detection device adjusts, in accordance with the temperature of the radiation detection element, the value of a parameter of a signal processing unit that determines the intensity of a signal generated in response to radiation incident on the radiation detection element. The generated signal changes depending on the temperature of the radiation detection element. By adjusting the value of the parameter in accordance with the temperature, it becomes possible to accurately determine the intensity of the signal in response to radiation.

[0012] In a radiation detection device according to one embodiment of the present invention, when the control unit receives an instruction to adjust the atmosphere inside the sample chamber to either a state in which the inside of the sample chamber is depressurized or a state in which the specified gas is introduced into the inside of the sample chamber, the control unit sets the atmosphere inside the sample chamber to be adjusted by the atmosphere adjustment unit in accordance with the received instruction.

[0013] In one aspect of the present invention, the radiation detection device receives an instruction to adjust the atmosphere inside the sample chamber to either a state where the inside of the sample chamber is depressurized or a state where a predetermined gas is introduced into the sample chamber, and sets the atmosphere in accordance with the received instruction, making it possible to adjust the atmosphere inside the sample chamber in accordance with an instruction from a user.

[0014] In a radiation detection device according to one aspect of the present invention, the atmosphere adjustment unit includes a pressure reduction unit that reduces the pressure inside the sample chamber, a gas supply unit that supplies the specified gas into the sample chamber, and a valve that connects either the pressure reduction unit or the gas supply unit to the sample chamber.

[0015] In one aspect of the present invention, the atmosphere adjustment unit includes a pressure reduction unit, a gas supply unit that supplies a predetermined gas into the inside of the sample chamber, and a valve that connects either the pressure reduction unit or the gas supply unit to the sample chamber. The radiation detection device adjusts the atmosphere inside the sample chamber by operating the pressure reduction unit, the gas supply unit, and the valve in accordance with the setting of the atmosphere inside the sample chamber to be adjusted.

[0016] A radiation detection device according to one aspect of the present invention further includes a housing that houses the radiation detection element therein, the housing having an unblocked opening.

[0017] In one embodiment of the present invention, the radiation detection element is accommodated in a housing, and the housing has an opening that is not covered by a window material. Radiation that passes through the opening is incident on the radiation detection element and is detected. The radiation detection device can detect radiation that is too low in energy to pass through the window material.

[0018] A radiation detection device according to one aspect of the present invention is characterized in that it further includes an irradiation unit that irradiates the sample with radiation, a spectrum generation unit that generates a spectrum of the radiation detected using the radiation detection element, and a display unit that displays the spectrum generated by the spectrum generation unit.

[0019] In one aspect of the present invention, the radiation detection device irradiates a sample with radiation, generates a spectrum of the radiation emitted from the sample, and displays the generated spectrum on a display unit, allowing a user to check the spectrum of the radiation emitted from the sample.

[0020] In one aspect of the radiation detection device of the present invention, the control unit changes the range of radiation energy indicated by the spectrum displayed by the display unit in accordance with the atmosphere inside the sample chamber.

[0021] In one aspect of the present invention, the radiation detection device changes the energy range shown in the spectrum when radiation is detected with the sample chamber pressure reduced and when helium is introduced into the sample chamber. Specifically, the radiation detection device increases the minimum energy value shown in the spectrum when radiation is detected with helium introduced into the sample chamber. Data in the low energy range, which is increasingly affected by noise as the temperature increases, is no longer included in the spectrum, and unreliable data is removed from the spectrum.

[0022] A control method according to one embodiment of the present invention is a method for controlling a radiation detection device comprising: a sample chamber in which a sample is placed; a radiation detection element placed in the sample chamber for detecting radiation emitted from the sample; an atmosphere adjustment unit that adjusts the atmosphere inside the sample chamber to one of a state in which the interior of the sample chamber is reduced in pressure and a state in which a predetermined gas is introduced into the interior of the sample chamber; and a temperature adjustment unit that adjusts the temperature of the radiation detection element, wherein when the atmosphere adjustment unit adjusts the atmosphere inside the sample chamber to a state in which the predetermined gas has been introduced, the control method is characterized in that when the atmosphere adjustment unit adjusts the atmosphere inside the sample chamber to a state in which the interior of the sample chamber is reduced in pressure, the temperature adjustment unit adjusts the temperature of the radiation detection element to a higher temperature than when the atmosphere adjustment unit adjusts the atmosphere inside the sample chamber to a state in which the interior of the sample chamber is reduced in pressure.

[0023] A computer program according to one aspect of the present invention causes a computer to control a radiation detection device including a sample chamber in which a sample is placed, a radiation detection element placed in the sample chamber for detecting radiation emitted from the sample, an atmosphere adjustment unit that adjusts the atmosphere inside the sample chamber to one of a state in which the inside of the sample chamber is reduced in pressure and a state in which a predetermined gas is introduced into the sample chamber, and a temperature adjustment unit that adjusts the temperature of the radiation detection element, to receive an instruction to adjust the atmosphere inside the sample chamber to one of a state in which the inside of the sample chamber is reduced in pressure and a state in which the predetermined gas is introduced into the sample chamber, and to execute a process of setting a target value of the temperature of the radiation detection element to a predetermined first temperature when the instruction to adjust the atmosphere inside the sample chamber to a state in which the predetermined gas is introduced into the sample chamber is received, and setting the target value of the temperature of the radiation detection element to a predetermined second temperature that is higher than the first temperature when the instruction to adjust the atmosphere inside the sample chamber to a state in which the predetermined gas is introduced into the sample chamber is received.

[0024] In one aspect of the present invention, the radiation detection device is controlled to adjust the atmosphere inside the sample chamber to one of a reduced pressure state and a state in which a predetermined gas is introduced into the sample chamber. The radiation detection device is controlled to adjust the temperature of the radiation detection element when the predetermined gas is introduced into the sample chamber to a higher temperature than when the pressure inside the sample chamber is reduced. Even when the predetermined gas is introduced into the sample chamber, it is possible to appropriately adjust the temperature of the radiation detection element.

[0025] According to the present invention, the temperature of the radiation detection element can be appropriately adjusted.

[0026] FIG. 1 is a block diagram showing an example of the functional configuration of a radiation detection device. FIG. 2 is a schematic cross-sectional view showing the configuration of a radiation detector. FIG. 3 is a schematic cross-sectional view showing a radiation detection element and a collimator. FIG. 4 is a block diagram showing an example of the internal configuration of a control unit. FIG. 5 is a conceptual diagram showing an example of the contents of temperature parameter data. FIG. 6 is a conceptual diagram showing an example of the contents of signal parameter data. FIG. 7 is a flowchart showing the procedure of a process for starting radiation detection executed by a control unit. FIG. 8 is a schematic diagram showing an example of a received image.

[0027] The present invention will be described in detail below with reference to the drawings illustrating embodiments thereof. FIG. 1 is a block diagram showing an example of the functional configuration of a radiation detection apparatus 100. The radiation detection apparatus 100 is, for example, an X-ray fluorescence analysis apparatus. The radiation detection apparatus 100 includes a sample stage 21 on which a sample 6 is placed, an irradiation unit 22 that irradiates the sample 6 with radiation such as an electron beam or X-rays, and a radiation detector 1. Radiation is irradiated from the irradiation unit 22 to the sample 6, causing characteristic X-rays such as fluorescent X-rays to be generated in the sample 6, and the radiation detector 1 detects the characteristic X-rays generated from the sample 6. In the drawing, the radiation and characteristic X-rays are indicated by arrows. Note that the radiation detection apparatus 100 may be configured to hold the sample 6 by a method other than placing it on the sample stage 21.

[0028] The radiation detection device 100 includes a sample chamber 2. The sample chamber 2 is box-shaped and has an openable and closable lid 20. The sample chamber 2 is closed when the lid 20 is closed. A sample stage 21, an irradiation unit 22, and a radiation detector 1 are arranged inside the sample chamber 2. The sample 6 is placed on the sample stage 21, thereby placing the sample 6 inside the sample chamber 2. The irradiation unit 22 may be configured to irradiate radiation from outside the sample chamber 2 to the sample 6 placed inside the sample chamber 2.

[0029] The radiation detector 1 includes a radiation detection element 11, a preamplifier 12, and a temperature sensor 13. A portion of the preamplifier 12 may be included inside the radiation detector 1, with the other portion being located outside the radiation detector 1. The temperature sensor 13 measures the temperature inside the radiation detector 1. For example, the temperature sensor 13 is configured using a thermistor or a thermocouple. The radiation detector 1 is connected to a voltage application unit 41 that applies a voltage required for radiation detection to the radiation detection element 11, a power supply unit 42 that supplies current and voltage to a Peltier element (described later) included in the radiation detector 1, and a signal processing unit 43. The voltage application unit 41 also applies a voltage required for the preamplifier 12 to operate to the preamplifier 12. An analysis unit 44 is connected to the signal processing unit 43. The analysis unit 44 is configured using a computer.

[0030] The radiation detection device 100 includes a control unit 3. The control unit 3 is connected to the radiation detector 1, a voltage application unit 41, a power supply unit 42, a signal processing unit 43, and an analysis unit 44. The control unit 3 controls the operations of the irradiation unit 22, the radiation detector 1, the voltage application unit 41, the power supply unit 42, the signal processing unit 43, and the analysis unit 44. An operation unit 45 and a display unit 46 are connected to the control unit 3 and the analysis unit 44. The operation unit 45 receives input of information such as text by receiving operations from the user. The operation unit 45 is, for example, a touch panel, a keyboard, or a pointing device. The display unit 46 displays images. The display unit 46 is, for example, a liquid crystal display or an EL display (electroluminescent display).

[0031] Outside the sample chamber 2, there are arranged a pressure reduction unit 51 that reduces the pressure inside the sample chamber 2, a gas supply unit 52 that supplies a predetermined gas into the sample chamber 2, and a valve 53. In this embodiment, the predetermined gas is helium. The sample chamber 2 and the valve 53 are connected by piping. The valve 53 is connected to the pressure reduction unit 51 and the gas supply unit 52, respectively, by piping. The valve 53 selectively connects either the pressure reduction unit 51 or the gas supply unit 52 to the sample chamber 2. For example, the valve 53 is configured using a three-way valve. The valve 53 is a valve whose operation can be controlled externally, such as an electromagnetic valve. The valve 53 may be configured by multiple valves, and the pressure reduction unit 51 and the gas supply unit 52 may be individually connected to the sample chamber 2 via one of the valves.

[0032] The pressure reducing unit 51 is connected to the sample chamber 2 and reduces the pressure inside the sample chamber 2 while the sample chamber 2 is sealed. The pressure reducing unit 51 can also return the gas pressure inside the sample chamber 2 to the same pressure outside the sample chamber 2 by introducing air from outside the sample chamber 2 into the sample chamber 2. The pressure reducing unit 51 is configured using, for example, a vacuum pump and a leak valve. The gas supply unit 52 is connected to the sample chamber 2 and supplies a predetermined gas to the reduced pressure inside the sample chamber 2. The predetermined gas is a gas that absorbs radiation such as electron beams or X-rays less than air. Low radiation absorption means a low radiation absorption rate or a high radiation transmittance. In this embodiment, the predetermined gas is helium. The gas supply unit 52 is configured using, for example, a gas tank that stores helium and a solenoid valve.

[0033] The radiation detection device 100 is equipped with a gas pressure sensor 54 that measures the pressure of the gas (gas pressure) inside the sample chamber 2. The pressure reducing unit 51, the gas supply unit 52, the valve 53, and the gas pressure sensor 54 are connected to the control unit 3. The control unit 3 controls the operations of the pressure reducing unit 51, the valve 53, and the gas supply unit 52.

[0034] The pressure reducing unit 51, the valve 53, and the gas supply unit 52 correspond to an atmosphere adjusting unit that adjusts the atmosphere inside the sample chamber 2. The valve 53 connects the pressure reducing unit 51 to the sample chamber 2, and the pressure reducing unit 51 reduces the pressure inside the sample chamber 2, thereby reducing the pressure inside the sample chamber 2. The valve 53 connects the gas supply unit 52 to the sample chamber 2, and the gas supply unit 52 supplies helium into the sample chamber 2, thereby introducing helium into the sample chamber 2. For example, the sample chamber 2 may be provided with an exhaust hole, a pressure valve, or an open / close valve (not shown) for exhausting air pushed by helium from the gas supply unit 52. The air may be exhausted through a gap between the sample chamber 2 and the lid 20.

[0035] FIG. 2 is a schematic cross-sectional view showing the configuration of the radiation detector 1. The radiation detector 1 is an SDD (Silicon Drift Detector). The radiation detector 1 includes a housing 17 shaped like a cylinder with a truncated cone connected to one end. The housing 17 includes a plate-like bottom plate covered with a cap-like cover. An opening 171 is formed at the tip of the housing 17. The opening 171 does not include a window having a window material, and is not blocked. The radiation detection element 11, the collimator 14, the circuit board 15, the Peltier element 16, and the cold finger 18 are arranged inside the housing 17. The housing 17 accommodates the radiation detection element 11, the collimator 14, the circuit board 15, and the Peltier element 16. The housing 17 accommodates the radiation detection element 11, physically protects the radiation detection element 11, and blocks light in areas other than the opening 171. The shape of the housing 17 is not limited to the shape shown in FIG. 2, and may be any other shape as long as it can fulfill its function.

[0036] The Peltier element 16 is connected to a power supply unit 42 and is supplied with voltage and current from the power supply unit 42. When a voltage is supplied to the Peltier element 16, a temperature difference is generated between one end and the other end. One end serves as a heat absorption end that absorbs heat, and the other end serves as a heat dissipation end that releases heat. The Peltier element 16 and the power supply unit 42 correspond to a temperature adjustment unit.

[0037] The radiation detection element 11 is mounted on the surface of the circuit board 15, and is disposed at a position facing the opening 171. The collimator 14 is cylindrical with both ends open, and is made of a radiation-shielding material. The collimator 14 is disposed between the radiation detection element 11 and the opening 171. One end of the collimator 14 faces the opening 171, and the other end faces the surface of the radiation detection element 11. Radiation mainly passes through the opening 171 and enters the inside of the housing 17, and the collimator 14 blocks part of the radiation. The radiation detection element 11 detects radiation that is not blocked by the collimator 14 and enters the housing 17.

[0038] A circuit is formed on the circuit board 15, and a preamplifier 12 and a temperature sensor 13 are mounted on it. For example, the temperature sensor 13 is configured using a thermistor or a thermocouple. The temperature sensor 13 measures the temperature inside the radiation detector 1. The temperature sensor 13 is connected to the control unit 3. The temperature sensor 13 measures the temperature inside the radiation detector 1, thereby measuring the temperature of the radiation detection element 11. The temperature sensor 13 may be disposed at a position other than the position shown in FIG. 2 , such as a position in contact with the radiation detection element 11.

[0039] The back surface of the circuit board 15 is in thermal contact with one end of the Peltier element 16, either directly or via an intervening object. A shield plate for blocking radiation generated from the Peltier element 16 may be disposed between the circuit board 15 and the Peltier element 16. The other end of the Peltier element 16 is in thermal contact with the cold finger 18. The cold finger 18 has a flat portion with which the other end of the Peltier element 16 is in thermal contact, and a portion that penetrates the bottom plate of the housing 17.

[0040] When one end of the Peltier element 16 that is in thermal contact with the circuit board 15 serves as a heat absorption end, heat from the radiation detection element 11 is absorbed by the Peltier element 16 through the circuit board 15. The heat is transferred from the Peltier element 16 to the cold finger 18 and dissipated to the outside of the radiation detector 1 through the cold finger 18. In this way, the Peltier element 16 cools the radiation detection element 11. The power supply unit 42 is controlled by the control unit 3 to supply voltage and current to the Peltier element 16.

[0041] The radiation detector 1 has a plurality of lead pins 19 penetrating the bottom plate portion of the housing 17. The lead pins 19 are connected to the circuit board 15 by a method such as wire bonding. The application of voltage to the radiation detection element 11 by the voltage application unit 41, the supply of voltage and current to the Peltier element 16 by the power supply unit 42, and the output of a signal from the preamplifier 12 are all performed through the lead pins 19. The temperature sensor 13 is connected to the control unit 3 via the lead pins 19. The radiation detector 1 may further include other components.

[0042] FIG. 3 is a schematic cross-sectional view showing the radiation detection element 11 and the collimator 14. The radiation detection element 11 is a silicon drift type radiation detection element. The radiation detection element 11 is generally flat. The radiation detection element 11 includes a plate-shaped semiconductor portion 112 made of Si (silicon). The radiation detection element 11 has an incident surface 111 located on the incident side where radiation to be detected is incident, and an electrode surface 116 located on the back side of the incident surface 111. A portion of the incident surface 111 is covered with the collimator 14. The radiation detection element 11 is arranged so that the electrode surface 116 faces the circuit board 15 and the incident surface 111 faces the opening 171. An electrode layer 113 is provided on a portion of the semiconductor portion 112 on the incident surface 111 side.

[0043] A signal output electrode 115, which is an electrode that outputs a signal when radiation is detected, and a plurality of curved electrodes 114 that form multiple rings in a planar view are provided in a portion of the semiconductor portion 112 on the electrode surface 116 side. The plurality of curved electrodes 114 surround the signal output electrode 115, and the distances between the signal output electrode 115 and each curved electrode 114 vary. Although four curved electrodes 114 are shown in FIG. 3 , more curved electrodes 114 are actually provided. The innermost curved electrode 114 and the outermost curved electrode 114 are connected to a voltage application unit 41. The electrode layer 113 is also connected to the voltage application unit 41. When a voltage is applied from the voltage application unit 41 to the curved electrodes 114 and the electrode layer 113, an electric field (potential gradient) is generated inside the semiconductor portion 112, with the potential increasing toward the signal output electrode 115.

[0044] Radiation is irradiated from the irradiation unit 22 onto the sample 6, and characteristic X-rays such as fluorescent X-rays are generated in the sample 6 and enter the radiation detector 1. The radiation consisting of characteristic X-rays mainly passes through the opening 171 and enters the interior of the radiation detector 1. A portion of the radiation that enters the interior of the radiation detector 1 is blocked by the collimator 14. The radiation that is not blocked by the collimator 14 enters the radiation detection element 11. The radiation that enters the radiation detection element 11 enters the semiconductor portion 112. The radiation is absorbed in the semiconductor portion 112, and electrons and holes are generated in amounts corresponding to the energy of the absorbed radiation. In this embodiment, the electric field inside the semiconductor portion 112 causes electrons to move and flow into the signal output electrode 115. The signal output electrode 115 outputs a current signal according to the electrons that have flowed in.

[0045] The signal output electrode 115 is connected to the preamplifier 12. The signal output by the signal output electrode 115 is input to the preamplifier 12. The preamplifier 12 converts the current signal into a voltage signal. The preamplifier 12 is connected to the signal processing unit 43. When the preamplifier 12 outputs a signal, the radiation detector 1 outputs a signal having an intensity corresponding to the energy of the radiation to the signal processing unit 43.

[0046] The signal processing unit 43 receives the signal output by the radiation detector 1 and determines the signal intensity, thereby detecting the signal intensity corresponding to the energy of the radiation detected by the radiation detector 1. The signal processing unit 43 counts the signals by signal intensity, and outputs data indicating the relationship between the signal intensity and the count number to the analysis unit 44.

[0047] The analysis unit 44 receives data indicating the relationship between the signal intensity and the count number output by the signal processing unit 43. The analysis unit 44 generates a spectrum of the radiation incident on the radiation detector 1 based on the data from the signal processing unit 43. Since the signal intensity corresponds to the energy of the radiation and the count number corresponds to the number of times the radiation is detected, i.e., the intensity of the radiation, the spectrum of the radiation can be obtained from the relationship between the signal intensity and the count number. The spectrum represents the relationship between the energy of the radiation and the intensity of the radiation. The process of counting the signals output by the radiation detector 1 by signal intensity may be performed by the analysis unit 44 instead of the signal processing unit 43. The generation of the radiation spectrum may be performed by the signal processing unit 43. The analysis unit 44 stores spectral data representing the spectrum of the radiation. The analysis unit 44 corresponds to a spectrum generation unit.

[0048] The display unit 46 displays the spectrum of the radiation. The user can check the spectrum of the characteristic X-rays generated from the sample 6. The analysis unit 44 may further perform information processing based on the spectrum of the radiation. For example, the analysis unit 44 performs qualitative analysis or quantitative analysis of the elements contained in the sample 6 based on the spectrum of the characteristic X-rays from the sample 6.

[0049] FIG. 4 is a block diagram showing an example of the internal configuration of the control unit 3. The control unit 3 is configured using a computer such as a personal computer. The control unit 3 executes a control method. The control unit 3 includes a calculation unit 31, a memory 32, a reading unit 33, a storage unit 34, and an interface unit 35. The calculation unit 31 is a processor and is configured using, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), or a multi-core CPU. The calculation unit 31 may also be configured using a quantum computer. The memory 32 stores temporary data generated in conjunction with calculations. The memory 32 is, for example, a RAM (Random Access Memory). The reading unit 33 reads information from a recording medium 30 such as an optical disc or a portable memory. The storage unit 34 is non-volatile and is, for example, a hard disk or non-volatile semiconductor memory.

[0050] The calculation unit 31 causes the reading unit 33 to read the computer program 341 recorded on the recording medium 30, and stores the read computer program 341 in the storage unit 34. The calculation unit 31 executes processing required for the control unit 3 in accordance with the computer program 341. The computer program 341 may be a program product. The computer program 341 may be downloaded from outside the control unit 3. Alternatively, the computer program 341 may be pre-stored in the storage unit 34. In these cases, the control unit 3 does not need to include the reading unit 33.

[0051] The computer program 341 can be deployed to run on a single computer, or on multiple computers located at one site or distributed across multiple sites and interconnected by a communications network. That is, the control unit 3 may be configured with multiple computers, and the computer program 341 may run on multiple computers connected via a communications network. The control unit 3 may be configured using a cloud server. The control unit 3 and the analysis unit 44 may be configured with the same computer.

[0052] The processing of each step described below for executing the control method can be executed by multiple computers. The processing of each step can also be executed by different computers. The processing of each step can also be executed using a virtual machine. The processing of each step may be executed by multiple calculation units. The processing of each step may also be executed by different calculation units.

[0053] An operation unit 45 and a display unit 46 are connected to the control unit 3. Other parts of the radiation detection device 100 are connected to the interface unit 35. A user operates the operation unit 45 to input various instructions, such as an instruction to start measurement, to the control unit 3. The control unit 3 accepts the instructions input using the operation unit 45. The display unit 46 displays an image. The control unit 3 outputs information necessary for radiation detection by displaying an image including information on the display unit 46. The control unit 3 accepts information necessary for control by accepting signals from each part of the radiation detection device 100 through the interface unit 35. The control unit 3 controls the operation of each part by transmitting control signals to each part of the radiation detection device 100 through the interface unit 35.

[0054] In the radiation detection device 100, the opening 171 is not blocked by a window material, and radiation that passes through the opening 171 is detected. Since the detected radiation does not need to pass through a window material, the radiation detection device 100 can detect radiation that has low energy and cannot pass through a window material. In other words, the radiation detection device 100 has high sensitivity for detecting low-energy radiation. Furthermore, the radiation detection device 100 detects radiation with the radiation detection element 11 cooled by the Peltier element 16.

[0055] In the radiation detection device 100, radiation detection is often performed with the sample chamber 2 depressurized to improve detection sensitivity. However, if the sample 6 is a powder, there is a possibility that the sample 6 will scatter when the pressure is reduced. Furthermore, if the sample 6 is a liquid, there is a possibility that the sample 6 will evaporate when the pressure is reduced inside the sample chamber 2. As such, it is not desirable to place some samples 6 in a depressurized atmosphere. In addition, it is also not desirable to place samples that contain water, samples that cannot be dried, or samples that will expand and burst in a depressurized atmosphere (e.g., biological samples) in a depressurized atmosphere.

[0056] In the radiation detection device 100, when using a sample 6 that is not preferably placed in a reduced pressure atmosphere, radiation detection is performed with helium introduced into the sample chamber 2. In helium, there is a low possibility that powder will scatter and a low possibility that liquid will evaporate. Other samples that are not preferably placed in a reduced pressure atmosphere can also be maintained in helium. Therefore, even if the sample 6 is not preferably placed in a reduced pressure atmosphere, there is no problem in placing the sample 6 in helium. Because radiation absorption is lower in helium than in air, performing radiation detection in helium can improve detection sensitivity compared to performing radiation detection in air.

[0057] When helium is introduced into the sample chamber 2, it enters the radiation detector 1 through the opening 171. At this time, the air is almost entirely replaced with helium at least around the irradiation unit 22, the sample stage 21, and the radiation detector 1. As a result, radiation passes through the helium. Absorption of radiation is reduced compared to when radiation passes through air. Because the thermal conductivity of helium is higher than that of a reduced-pressure atmosphere, more heat flows into the radiation detection element 11 when the radiation detection element 11 is cooled by the Peltier element 16. Therefore, when helium is introduced into the sample chamber 2, the radiation detection element 11 is more difficult to cool than when the inside of the sample chamber 2 is reduced in pressure.

[0058] In this embodiment, when helium is introduced into the sample chamber 2, the control unit 3 adjusts the temperature of the radiation detection element 11 to a higher temperature than when the pressure inside the sample chamber 2 is reduced. The storage unit 34 stores temperature parameter data 342 that records parameters used to adjust the temperature of the radiation detection element 11.

[0059] FIG. 5 is a conceptual diagram illustrating an example of the temperature parameter data 342. The temperature parameter data 342 includes, as parameters, target temperature values ​​of the radiation detection element 11 to be adjusted using the Peltier element 16. The target temperature values ​​are predetermined for each of two types of atmospheres within the sample chamber 2. The atmosphere within the sample chamber 2 when the sample chamber 2 is depressurized is defined as a reduced-pressure atmosphere, and the atmosphere within the sample chamber 2 when helium is introduced into the sample chamber 2 is defined as a helium atmosphere. As target temperature values, a first temperature is recorded for the reduced-pressure atmosphere, and a second temperature is recorded for the helium atmosphere. The second temperature is higher than the first temperature. For example, the first temperature is −10° C. and the second temperature is +5° C. For example, the first temperature can range from −40° C. to −5° C., and the second temperature can range from 0° C. to +15° C. The temperature parameter data 342 may also include values ​​of other parameters for temperature adjustment.

[0060] The storage unit 34 also stores signal parameter data 343, which records parameters necessary for signal processing in which the signal processing unit 43 determines the intensity of the signal output from the radiation detector 1. FIG. 6 is a conceptual diagram showing an example of the contents of the signal parameter data 343. The zero point, gain, noise threshold, and waveform shaping time constant are recorded as parameters for each of the reduced pressure atmosphere and the helium atmosphere. The values ​​of each parameter are different for the reduced pressure atmosphere and the helium atmosphere. The value of each parameter is predetermined to a predetermined value corresponding to the temperature of the radiation detection element 11 to be adjusted when the atmosphere inside the sample chamber 2 is adjusted to a reduced pressure atmosphere, or a predetermined value corresponding to the temperature of the radiation detection element 11 to be adjusted when the atmosphere inside the sample chamber 2 is adjusted to a helium atmosphere.

[0061] The zero point is a value that determines which value of the signal is set as zero, the base point of intensity. When the temperature is high, leakage current not derived from radiation increases and the signal value rises, so the zero point is a larger value in a helium atmosphere than in a reduced pressure atmosphere. The gain is the gain when amplifying the signal from the radiation detector 1. Since the signal intensity differs depending on the temperature, the gain differs depending on the atmosphere. The noise threshold is a threshold for determining noise. A signal whose value or amplitude is less than the noise threshold is determined to be noise. When the temperature is high, the noise increases, so the noise threshold is a larger value in a helium atmosphere than in a reduced pressure atmosphere.

[0062] Each time an event occurs in which the radiation detection element 11 detects radiation, the radiation detector 1 outputs a staircase wave in which the signal value rises stepwise. Each time an event occurs, the signal value rises. The signal processing unit 43 determines the height of the step by which the signal value rises as the signal strength. Here, the signal processing unit 43 performs waveform shaping to shape the staircase wave into a trapezoidal wave, and determines the height of the trapezoidal wave to determine the step height. In waveform shaping, differentiation is performed on the signal during the period in which the signal value rises stepwise, which is included in the staircase wave, and smoothing is performed on the signal during the periods before and after the signal value rises, respectively. The time constant of waveform shaping is the time constant used by the signal processing unit 43 when performing waveform shaping.

[0063] The time constant for waveform shaping recorded in the signal parameter data 343 is, for example, HT (Holding Time), which is the length of time during which the signal value rises stepwise, or PT (Peaking Time), which is the length of time the signal is smoothed before and after the signal value rises. When the temperature changes, the slope of the signal value rise changes, and the time it takes for the signal value to reach its full rise also changes. The magnitude of noise also changes. Therefore, in order to appropriately differentiate and smooth the signal and accurately determine the step height, it is necessary to set HT and PT to appropriate values ​​according to the temperature. The signal parameter data 343 may record either HT or PT as the time constant for waveform shaping, or both HT and PT.

[0064] The value of each parameter recorded in the signal parameter data 343 is predetermined to a value that enables the signal processing unit 43 to accurately determine the signal intensity when the temperature of the radiation detection element 11 is adjusted to the respective temperature. The signal parameter data 343 may further record values ​​of other parameters for signal processing.

[0065] 7 is a flowchart showing the procedure of the process of starting radiation detection executed by the control unit 3. Hereinafter, steps are abbreviated as S. The control unit 3 executes the following process by the calculation unit 31 executing information processing in accordance with the computer program 341. With the sample 6 placed on the sample stage 21 and the lid unit 20 closed to close the sample chamber 2, the control unit 3 accepts an instruction to adjust the atmosphere (S1). In S1, the calculation unit 31 displays a reception image for accepting the instruction to adjust the atmosphere on the display unit 46, and the user operates the operation unit 45 to accept the instruction to adjust the atmosphere.

[0066] 8 is a schematic diagram showing an example of a reception image. The calculation unit 31 generates a reception image for receiving a selection of either a reduced pressure atmosphere or a helium atmosphere as the atmosphere inside the sample chamber 2 to be adjusted, and displays the image on the display unit 46. "Vacuum" in FIG. 8 indicates a reduced pressure atmosphere, and "Helium" indicates a helium atmosphere. In the example shown in FIG. 8, the reception image includes an icon for selecting the reduced pressure atmosphere and an icon for selecting the helium atmosphere.

[0067] The user selects the atmosphere depending on the sample 6. If the sample 6 is a powder or liquid, for example, that is not suitable for placement in a reduced pressure atmosphere, the user selects a helium atmosphere. If the sample 6 is a sample that may be placed in a reduced pressure atmosphere, for example, the user selects a reduced pressure atmosphere. The atmosphere inside the sample chamber 2 to be adjusted is selected by designating one of the icons in response to the user operating the operation unit 45. Figure 8 shows an example in which a reduced pressure atmosphere is selected. In this way, the calculation unit 31 accepts an instruction to adjust the atmosphere inside the sample chamber 2 to either a reduced pressure atmosphere or a helium atmosphere. The received image may be an image other than the example shown in Figure 8. The control unit 3 may accept an instruction by a method other than a method using a received image.

[0068] The control unit 3 sets the atmosphere inside the sample chamber 2 to be adjusted (S2). In S2, the calculation unit 31 sets the atmosphere inside the sample chamber 2 to be adjusted to a reduced pressure atmosphere or a helium atmosphere in accordance with the instruction received in S1. For example, the calculation unit 31 stores in the memory 32 that the atmosphere inside the sample chamber 2 should be adjusted to a reduced pressure atmosphere or a helium atmosphere.

[0069] The control unit 3 sets a target temperature value of the radiation detection element 11 to be adjusted using the Peltier element 16 (S3). In S3, the calculation unit 31 selects a target temperature value corresponding to the instruction received in S1 from the target temperature values ​​recorded in the temperature parameter data 342, and sets the target temperature value to the selected target value. If an instruction to adjust the atmosphere inside the sample chamber 2 to a reduced pressure atmosphere is received in S1, the calculation unit 31 sets the target temperature value to the first temperature recorded for the reduced pressure atmosphere in the temperature parameter data 342. If an instruction to adjust the atmosphere inside the sample chamber 2 to a helium atmosphere is received in S1, the calculation unit 31 sets the target temperature value to the second temperature recorded for the helium atmosphere in the temperature parameter data 342. For example, the calculation unit 31 stores in the memory 32 that the target temperature value of the radiation detection element 11 to be adjusted should be the first temperature or the second temperature. The calculation unit 31 may set other parameters for temperature adjustment.

[0070] The control unit 3 sets parameters for signal processing by the signal processing unit 43 (S4). In S4, the calculation unit 31 selects parameter values ​​corresponding to the temperature of the radiation detection element 11 to be adjusted from the parameter values ​​recorded in the signal parameter data 343, and sets the parameter values ​​to the selected values. If the atmosphere inside the sample chamber 2 is set to be adjusted to a reduced pressure atmosphere, the calculation unit 31 sets the signal processing parameter values ​​to the values ​​recorded for the reduced pressure atmosphere in the signal parameter data 343. If the atmosphere inside the sample chamber 2 is set to be adjusted to a helium atmosphere, the calculation unit 31 sets the signal processing parameter values ​​to the values ​​recorded for the helium atmosphere in the signal parameter data 343. For example, the calculation unit 31 stores the signal processing parameter values ​​in the memory 32. Through the process of S4, the signal processing parameter values ​​are adjusted to values ​​that allow the signal processing unit 43 to accurately determine the signal intensity, depending on the temperature of the radiation detection element 11.

[0071] The control unit 3 then adjusts the atmosphere inside the sample chamber 2 (S5). In S5, when the setting is made to adjust the atmosphere inside the sample chamber 2 to a reduced pressure atmosphere, the calculation unit 31 sends a control signal to the valve 53, causing the valve 53 to connect the pressure reduction unit 51 to the sample chamber 2. The calculation unit 31 also sends a control signal to the pressure reduction unit 51 to operate it. The pressure reduction unit 51 reduces the pressure inside the sample chamber 2. The control unit 3 receives a signal indicating the gas pressure inside the sample chamber 2 measured by the gas pressure sensor 54. The calculation unit 31 operates the pressure reduction unit 51 until the gas pressure inside the sample chamber 2 measured by the gas pressure sensor 54 becomes equal to or lower than a predetermined pressure. In this way, the atmosphere inside the sample chamber 2 is adjusted to a reduced pressure atmosphere.

[0072] When the atmosphere inside the sample chamber 2 is set to be adjusted to a helium atmosphere, the calculation unit 31 sends a control signal to the valve 53, causing the valve 53 to connect the gas supply unit 52 to the sample chamber 2. The calculation unit 31 also sends a control signal to the gas supply unit 52, causing the gas supply unit 52 to operate. The gas supply unit 52 supplies helium into the sample chamber 2. The air is pushed out by the helium, and the helium is introduced into the sample chamber 2. In this way, the atmosphere inside the sample chamber 2 is adjusted to a helium atmosphere.

[0073] The control unit 3 then adjusts the temperature of the radiation detection element 11 using the Peltier element 16 (S6). In S6, the calculation unit 31 sends a control signal to the power supply unit 42, causing the power supply unit 42 to supply current and voltage to the Peltier element 16, thereby causing the Peltier element 16 to adjust the temperature of the radiation detection element 11. The control unit 3 receives a signal indicating the temperature measured by the temperature sensor 13. The calculation unit 31 identifies the temperature of the radiation detection element 11 based on the signal from the temperature sensor 13 and controls the operation of the power supply unit 42 so that the temperature of the radiation detection element 11 becomes the set target value. In this way, when the atmosphere inside the sample chamber 2 is adjusted to a reduced pressure atmosphere, the Peltier element 16 adjusts the temperature of the radiation detection element 11 to the first temperature. Furthermore, when the atmosphere inside the sample chamber 2 is adjusted to a helium atmosphere, the Peltier element 16 adjusts the temperature of the radiation detection element 11 to the second temperature.

[0074] The control unit 3 then starts radiation detection (S7). In S7, the calculation unit 31 sends a control signal to the voltage application unit 41, causing the voltage application unit 41 to apply a voltage required for radiation detection to the radiation detection elements 11. The application of voltage puts the radiation detection elements 11 in a state where they can detect radiation. The calculation unit 31 sends a control signal to the irradiation unit 22, causing the irradiation unit 22 to irradiate radiation. The irradiation unit 22 irradiates the sample 6 with radiation, and characteristic X-rays are generated from the sample 6. The radiation consisting of characteristic X-rays is incident on the radiation detection elements 11 in the radiation detector 1, and the radiation detection elements 11 output a current signal corresponding to the radiation, and the preamplifier 12 converts the current signal into a voltage signal.

[0075] The signal processing unit 43 performs signal processing by determining the signal intensity to detect the signal intensity corresponding to the radiation energy and counting the signals for each signal intensity. When performing signal processing, the signal processing unit 43 uses set values ​​as signal processing parameter values. For example, the control unit 3 inputs the set parameter values ​​to the signal processing unit 43, and the signal processing unit 43 performs signal processing using the input parameter values. The analysis unit 44 generates a radiation spectrum. In this way, characteristic X-rays emitted from the sample 6 are detected and a characteristic X-ray spectrum is generated.

[0076] The control unit 3 then outputs the generated spectrum of the radiation (S8). In S8, the calculation unit 31 outputs the spectrum of the radiation by displaying an image including the generated spectrum on the display unit 46. The spectrum represents the relationship between the energy and intensity of the radiation. For example, the horizontal axis of the spectrum represents the energy of the radiation, and the vertical axis represents the intensity (count number) of the radiation having each energy. At this time, the calculation unit 31 changes the energy range shown in the spectrum depending on whether the radiation is detected with the sample chamber 2 pressure reduced or with helium introduced into the sample chamber 2. Specifically, when the radiation is detected with helium introduced into the sample chamber 2, the calculation unit 31 increases the minimum energy value shown in the spectrum compared to when the radiation is detected with the sample chamber 2 pressure reduced.

[0077] When helium is introduced into the sample chamber 2, the temperature of the radiation detection element 11 is higher than when the sample chamber 2 is depressurized. This increases the noise contained in the signal output by the radiation detection element 11. When the radiation energy is low, the step height of the staircase wave is small, and the noise has a significant effect on the signal intensity determined by the signal processing unit 43, i.e., the radiation energy. Therefore, when helium is introduced into the sample chamber 2, the reliability of the radiation energy in the low-energy range is reduced compared to when the sample chamber 2 is depressurized. By increasing the minimum energy value indicated in the spectrum, data corresponding to energies below the minimum value are not included in the spectrum, and unreliable data is removed from the spectrum. In this way, when radiation is detected with helium introduced into the sample chamber 2, the control unit 3 can remove unreliable data from the spectrum by increasing the minimum energy value indicated in the spectrum, thereby suppressing deterioration in the reliability of the spectrum. The control unit 3 may also control the analysis unit 44 to adjust the energy range indicated in the spectrum according to the atmosphere when generating a radiation spectrum.

[0078] The analysis unit 44 may perform further analysis, such as qualitative analysis or quantitative analysis of elements contained in the sample 6, based on the spectrum of the radiation. In this case, the analysis unit 44 changes the range of radiation energy used in the analysis depending on whether the radiation is detected with the sample chamber 2 depressurized or with helium introduced into the sample chamber 2. Specifically, when the radiation is detected with helium introduced into the sample chamber 2, the analysis unit 44 increases the minimum value of the radiation energy used in the analysis compared to when the radiation is detected with the sample chamber 2 depressurized.

[0079] When helium is introduced into the sample chamber 2, the reliability of the radiation energy in the low energy range deteriorates compared to when the pressure inside the sample chamber 2 is reduced, and the reliability of the analysis results using data in the low energy range deteriorates. By increasing the minimum value of the radiation energy used in the analysis, data corresponding to energies below the minimum value will not be used in the analysis. This prevents the deterioration of the reliability of the analysis results based on the radiation spectrum. For example, the control unit 3 controls the analysis unit 44 to change the range of radiation energy used in the analysis depending on the atmosphere. The control unit 3 then ends the process of starting radiation detection.

[0080] As described above in detail, in this embodiment, the radiation detection device 100 adjusts the atmosphere inside the sample chamber 2 to one of two states: a state in which the inside of the sample chamber 2 is depressurized, and a state in which helium is introduced into the sample chamber 2. When the inside of the sample chamber 2 is depressurized, the radiation detection device 100 adjusts the temperature of the radiation detection element 11 to a first temperature, and when helium is introduced into the sample chamber 2, the radiation detection device 100 adjusts the temperature of the radiation detection element 11 to a second temperature higher than the first temperature.

[0081] Because the thermal conductivity of helium gas is higher than the thermal conductivity of a reduced-pressure atmosphere, the radiation detection element 11 is less likely to be cooled when helium is introduced into the sample chamber 2 than when the pressure inside the sample chamber 2 is reduced. The radiation detection device 100 adjusts the temperature of the radiation detection element 11 when helium is introduced into the sample chamber 2 to a higher temperature than the temperature of the radiation detection element 11 when the pressure inside the sample chamber 2 is reduced. Therefore, the radiation detection device 100 can appropriately adjust the temperature of the radiation detection element 11 even when helium is introduced into the sample chamber 2.

[0082] When helium is introduced into the sample chamber 2, if the radiation detection element 11 is to be cooled to a temperature equivalent to that when the sample chamber 2 is depressurized, the temperature adjustment unit including the Peltier element 16 requires high cooling performance. Improving the cooling performance of the temperature adjustment unit would result in an increase in size. In this embodiment, the temperature of the radiation detection element 11 when helium is introduced into the sample chamber 2 is adjusted to a higher temperature than the temperature of the radiation detection element 11 when the sample chamber 2 is depressurized, so there is no need to improve the cooling performance of the temperature adjustment unit. Since there is no need to improve the cooling performance of the temperature adjustment unit, an increase in size of the temperature adjustment unit can be prevented. Furthermore, an increase in cost due to improved cooling performance of the temperature adjustment unit can be prevented. When the sample chamber 2 is depressurized, the radiation detection device 100 adjusts the temperature of the radiation detection element 11 to a lower temperature than when helium is introduced into the sample chamber 2. Therefore, radiation detection sensitivity can be improved when detecting radiation when the sample chamber 2 is depressurized.

[0083] Furthermore, the radiation detection device 100 adjusts the values ​​of the signal processing parameters in the signal processing unit 43 according to the temperature of the radiation detection element 11 to be adjusted. The signal generated in response to radiation incident on the radiation detection element 11 changes depending on the temperature. By adjusting the values ​​of the signal processing parameters according to the temperature, it becomes possible to accurately determine the intensity of the signal generated at each temperature. Therefore, the radiation detection device 100 can accurately determine the intensity of the signal generated in response to radiation incident, and perform accurate radiation detection, both in a state where the inside of the sample chamber 2 is decompressed and in a state where helium is introduced into the sample chamber 2.

[0084] In this embodiment, the radiation detection device 100 is shown to have the voltage application unit 41 and the power supply unit 42 separately, but the voltage application unit 41 and the power supply unit 42 may be configured as an integrated unit. In this embodiment, an example is shown in which helium is used as the predetermined gas to be introduced into the sample chamber 2, but the predetermined gas may be a gas other than helium as long as it absorbs less radiation than air.

[0085] In this embodiment, the radiation detection element 11 is made of a semiconductor such as Si, but the radiation detection element 11 may be made of a semiconductor other than Si. In this embodiment, the radiation detection element 11 is made of a silicon drift type radiation detection element, but the radiation detection element 11 may be made of a semiconductor other than a silicon drift type radiation detection element. Therefore, the radiation detector 1 may be a radiation detector other than an SDD.

[0086] In the present embodiment, the radiation detector 1 includes the collimator 14, but the radiation detector 1 may not include the collimator 14. The radiation detector 1 may also not include the cold finger 18. In this embodiment, for example, the heat dissipation end of the Peltier element 16 contacts the housing 17 directly or via an intervening object, and heat is dissipated through the housing 17. The temperature adjustment unit may include a temperature adjustment mechanism other than the Peltier element 16. For example, the temperature adjustment unit may include a heater in addition to the Peltier element 16. The radiation detector 1 may not be provided with the opening 171, but may include a window having a window material, and detect radiation that has passed through the window. In the present embodiment, the radiation detection element 11 is housed in the housing 17, but the radiation detector 1 may not include the housing 17.

[0087] In this embodiment, a configuration has been shown in which radiation is irradiated onto the sample 6 and characteristic X-rays generated from the sample 6 are detected, but the radiation detection device 100 may be configured to detect other types of radiation. For example, the radiation detection device 100 may be configured to detect radiation that has passed through the sample 6 or radiation that has been reflected by the sample 6. The radiation detection device 100 may be configured to scan the sample 6 with radiation by changing the direction of the radiation or by moving the sample 6. In this embodiment, a configuration has been shown in which the radiation detection device 100 includes the irradiation unit 22, but the radiation detection device 100 may be configured not to include the irradiation unit 22.

[0088] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. In other words, embodiments obtained by combining technical means modified appropriately within the scope of the claims are also included in the technical scope of the present invention.

[0089] The matters described in each embodiment can be combined with each other. Furthermore, the independent claims and dependent claims described in the claims can be combined with each other in any and all combinations, regardless of the reference format. Furthermore, the claims use a format in which a claim references two or more other claims (multiple claim format), but this is not limited to this. A multiple claim (multi-multi claim) that references at least one other multiple claim may also be used.

[0090] REFERENCE SIGNS LIST 100 Radiation detection device 1 Radiation detector 11 Radiation detection element 16 Peltier element (temperature adjustment unit) 17 Housing 171 Opening 2 Sample chamber 22 Irradiation unit 3 Control unit 31 Calculation unit 341 Computer program 42 Power supply unit (temperature adjustment unit) 43 Signal processing unit 44 Analysis unit (spectrum generation unit) 46 Display unit 51 Pressure reduction unit (atmosphere adjustment unit) 52 Gas supply unit (atmosphere adjustment unit) 53 Valve (atmosphere adjustment unit)

Claims

1. A radiation detection device comprising: a sample chamber in which a sample is placed; a radiation detection element placed inside the sample chamber for detecting radiation generated from the sample; an atmosphere adjustment unit that adjusts the atmosphere inside the sample chamber to one of a state in which the inside of the sample chamber is reduced in pressure and a state in which a predetermined gas has been introduced into the inside of the sample chamber; a temperature adjustment unit that adjusts the temperature of the radiation detection element; and a control unit, wherein when the atmosphere adjustment unit adjusts the atmosphere inside the sample chamber to a state in which the predetermined gas has been introduced, the control unit causes the temperature adjustment unit to adjust the temperature of the radiation detection element to a higher temperature than when the atmosphere adjustment unit adjusts the atmosphere inside the sample chamber to a state in which the inside of the sample chamber is reduced in pressure.

2. The radiation detection device according to claim 1, characterized in that the control unit receives an instruction to adjust the atmosphere inside the sample chamber to either a state in which the inside of the sample chamber is depressurized or a state in which the specified gas has been introduced into the inside of the sample chamber, and when an instruction to adjust the atmosphere inside the sample chamber to a state in which the inside of the sample chamber is depressurized is received, the control unit sets a target value of the temperature of the radiation detection element to be adjusted by the temperature adjustment unit to a specified first temperature, and when an instruction to adjust the atmosphere inside the sample chamber to a state in which the specified gas has been introduced into the sample chamber is received, the control unit sets a target value of the temperature of the radiation detection element to be adjusted by the temperature adjustment unit to a specified second temperature which is higher than the first temperature.

3. The radiation detection device according to claim 1 or 2, further comprising a signal processing unit that determines the intensity of a signal generated in response to radiation being incident on the radiation detection element, and the control unit adjusts the parameter values ​​of the signal processing unit to values ​​corresponding to the temperature of the radiation detection element to be adjusted by the temperature adjustment unit.

4. A radiation detection device as described in any one of claims 1 to 3, characterized in that when the control unit receives an instruction to adjust the atmosphere inside the sample chamber to either a state in which the inside of the sample chamber is reduced in pressure or a state in which the specified gas is introduced into the inside of the sample chamber, the control unit sets the atmosphere inside the sample chamber to be adjusted by the atmosphere adjustment unit in accordance with the received instruction.

5. A radiation detection device as described in any one of claims 1 to 4, characterized in that the atmosphere adjustment unit has a pressure reduction unit that reduces the pressure inside the sample chamber, a gas supply unit that supplies the specified gas to the inside of the sample chamber, and a valve that connects either the pressure reduction unit or the gas supply unit to the sample chamber.

6. A radiation detection device according to any one of claims 1 to 5, further comprising a housing that houses the radiation detection element therein, the housing having an unblocked opening.

7. The radiation detection device according to any one of claims 1 to 6, further comprising: an irradiation unit which irradiates radiation onto the sample; a spectrum generation unit which generates a spectrum of the radiation detected using the radiation detection element; and a display unit which displays the spectrum generated by the spectrum generation unit.

8. The radiation detection device according to claim 7, characterized in that the control unit changes the range of radiation energy indicated by the spectrum displayed by the display unit in accordance with the atmosphere inside the sample chamber.

9. A method for controlling a radiation detection device comprising: a sample chamber in which a sample is placed; a radiation detection element placed inside the sample chamber for detecting radiation generated from the sample; an atmosphere adjustment unit for adjusting the atmosphere inside the sample chamber to one of a state in which the inside of the sample chamber is reduced in pressure and a state in which a predetermined gas is introduced into the inside of the sample chamber; and a temperature adjustment unit for adjusting the temperature of the radiation detection element, wherein when the atmosphere adjustment unit adjusts the atmosphere inside the sample chamber to a state in which the predetermined gas has been introduced, the control method causes the temperature adjustment unit to adjust the temperature of the radiation detection element to a higher temperature than when the atmosphere adjustment unit adjusts the atmosphere inside the sample chamber to a state in which the inside of the sample chamber is reduced in pressure.

10. A computer program for causing a computer to control a radiation detection device comprising: a sample chamber in which a sample is placed; a radiation detection element placed in the sample chamber for detecting radiation generated from the sample; an atmosphere adjustment unit for adjusting the atmosphere inside the sample chamber to one of a state in which the inside of the sample chamber is depressurized and a state in which a predetermined gas is introduced into the sample chamber; and a temperature adjustment unit for adjusting the temperature of the radiation detection element, the computer program causing the computer to execute a process of receiving an instruction to adjust the atmosphere inside the sample chamber to one of a state in which the inside of the sample chamber is depressurized and a state in which the predetermined gas is introduced into the sample chamber, setting a target value of the temperature of the radiation detection element to be adjusted by the temperature adjustment unit to a predetermined first temperature when the instruction to adjust the atmosphere inside the sample chamber to a state in which the inside of the sample chamber is depressurized and a state in which the predetermined gas is introduced into the sample chamber, and setting a target value of the temperature of the radiation detection element to be adjusted by the temperature adjustment unit to a predetermined second temperature higher than the first temperature when the instruction to adjust the atmosphere inside the sample chamber to a state in which the predetermined gas is introduced into the sample chamber is received.

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