A temperature calibration device for thermoluminescence measurement systems

Abstract

This invention discloses a temperature calibration device for a thermoluminescence measurement system, belonging to the field of thermoluminescence measurement technology. The device includes a sample assembly connected to a photomultiplier tube assembly, which is linked to an intelligent control module. The intelligent control module is connected to a heating device, which is in turn connected to the sample assembly. The intelligent control module includes a temperature detection and heating control circuit and a signal processing and intelligent control circuit. It calculates the cumulative CPS value and average CPS value of each thermoluminescent sheet in the sample assembly based on pulse signals, thereby calculating the relative error of each thermoluminescent sheet. Based on the relative error, it generates a heating control signal and outputs it to the heating device to adjust the heating temperature and perform different temperature compensations on each thermoluminescent sheet, ensuring the overall sample assembly is always in optimal operating condition. This invention improves the reliability of the system measurement by adding a temperature calibration function.

Description

Technical Field

[0001] This invention relates to the field of thermoluminescence measurement technology, and more particularly to a temperature calibration device for a thermoluminescence measurement system. Background Technology

[0002] Thermoluminescence measurement systems are used to measure the cumulative dose of thermoluminescent (HLM) sheets worn on the human body. An internal heating device raises the temperature of the HLM sheet to (240℃±1)℃, releasing the accumulated radiation dose as light. The greater the accumulated radiation dose, the stronger the luminescence intensity. The light emitted by the HLM sheet is received by a photomultiplier tube array, generating a pulsed current signal. This pulsed current signal is then processed by the acquisition and analysis device of the HLM measurement system. In actual use, due to oxidation of the metal surface or changes in the assembly state of the temperature sensor, the actual heating temperature of the HLM sheet may deviate from the controlled heating temperature. This can lead to insufficient heating, resulting in abnormal readings and further causing significant errors in the system's measurement results. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a temperature calibration device for a thermoluminescence measurement system. By designing a method for simultaneous measurement of multiple samples, individual temperature control of samples, and intelligent temperature calibration, it has the advantages of reducing measurement errors and improving the accuracy of system readings.

[0004] The objective of this invention is achieved through the following technical solution: a temperature calibration device for a thermoluminescence measurement system, comprising a sample assembly, wherein the sample assembly is connected to a photomultiplier tube assembly, the photomultiplier tube assembly is connected to an intelligent control module, the intelligent control module is connected to a heating device, and the heating device is connected to the sample assembly;

[0005] The sample assembly includes multiple thermoluminescent sheets, which are respectively arranged in multiple assembly areas separated by heat insulation material in the assembly groove, so as to realize independent heating of each thermoluminescent sheet.

[0006] The photomultiplier tube assembly includes multiple photomultiplier tubes, each configured to receive light signals emitted by a thermoluminescent sheet and convert the light signals into pulse signals; the pulse signals are output to the intelligent control module via a connector.

[0007] The intelligent control module includes a temperature detection and heating control circuit and a signal processing and intelligent control circuit. It is used to calculate the cumulative CPS value and average CPS value of each thermoluminescent sheet according to the pulse signal, thereby calculating the relative error of each thermoluminescent sheet, and generating a heating control signal based on the relative error and outputting it to the heating device to adjust the heating temperature to perform different temperature compensations on each thermoluminescent sheet, so that the overall sample combination is always in the optimal working state.

[0008] The heating device is used to heat each thermoluminescent sheet according to the heating control signal. It includes multiple heating sheets, each of which is equipped with a temperature detection unit. The heating sheet and the temperature detection unit are connected to a temperature detection and heating control circuit.

[0009] Preferably, a pressure plate is provided on the side of the thermoluminescent sheet away from the assembly groove, and the pressure plate is fixed to the assembly groove by screws.

[0010] Preferably, the photomultiplier tube assembly further includes a metal casing, which is used to shield the photomultiplier tube from light.

[0011] Preferably, the temperature detection and heating control circuit includes resistors R1, R2, R3, R4, R5, R6, R7, R8, and R9; capacitors C1, C2, C3, and C4; an instrumentation amplifier D1; a thyristor optocoupler U1; a thyristor Q1; and a field-effect transistor Q2. Specifically, capacitors C1, C2, and C4, resistors R2 and R4 form a first-order common-mode interference low-pass filter; instrumentation amplifier D1 and resistor R1 form an amplifier circuit; resistor R3 and capacitor C3 form a first-order differential-mode interference low-pass filter; and resistors R5, R6, R7, R8, and R9, the field-effect transistor Q2, the thyristor optocoupler U1, and the thyristor Q1 form a heating control circuit.

[0012] The first ends of resistors R2 and R4 are connected to the temperature detection unit. The second end of resistor R2 is connected to the positive input terminal of instrumentation amplifier D1, and the first ends of capacitors C1 and C2. The second end of resistor R4 is connected to the second end of capacitor C2, the first end of capacitor C4, and the negative input terminal of instrumentation amplifier D1. The second ends of capacitors C1 and C4 are connected to ground (GND). Pin 8 of instrumentation amplifier D1 is connected to the first end of resistor R1, and the second end of resistor R1 is connected to pin 1 of instrumentation amplifier D1. The output terminal of instrumentation amplifier D1 is connected to the first end of resistor R3. The second end of resistor R3 is connected to the first end of capacitor C3 and the microcontroller, outputting the temperature feedback signal to the microcontroller. The second end of capacitor C3 is connected to ground (GND).

[0013] The first terminal of resistor R7 receives the PWM signal, and the second terminal of resistor R7 is connected to the first terminal of resistor R9 and the gate of MOSFET Q2. The drain of MOSFET Q2 is connected to pin 2 of SCR optocoupler U1, and the source of MOSFET Q2 and the second terminal of resistor R9 are connected to ground (GND). Pin 1 of SCR optocoupler U1 is connected to the first terminal of resistor R5, pin 4 of SCR optocoupler U1 is connected to pin 3 of SCR Q1 and the first terminal of resistor R8, and pin 6 of SCR optocoupler U1 is connected to the first terminal of resistor R6. The second terminal of resistor R5 is connected to the power supply. The second terminal of resistor R6 is connected to the 220VAC live wire and pin 2 of SCR Q1. Pin 1 of SCR Q1 is connected to the second terminal of resistor R8 and the first terminal of heating element. The second terminal of heating element is connected to the 220VAC neutral wire.

[0014] Preferably, the signal processing and intelligent control circuit includes resistors R11, R12, R13, R14, R15, and R16, capacitor C11, operational amplifier D1A, operational amplifier D1B, comparator D2, and a microcontroller; wherein resistors R11, R12, and operational amplifier D1A form an I / V conversion circuit, resistors R13, R15, and R16 and operational amplifier D1B form a non-inverting amplifier, and capacitor C11 and resistor R14 form a first-order high-pass filter;

[0015] The first terminal of resistor R12 receives the pulse signal output by the photomultiplier tube assembly. The second terminal of resistor R12 is connected to the inverting input terminal of operational amplifier D1A and the first terminal of resistor R11. The output terminal of operational amplifier D1A is connected to the second terminal of resistor R11 and the first terminal of resistor R13. The non-inverting input terminal of operational amplifier D1A is connected to analog ground AGND. The second terminal of resistor R13 is connected to the non-inverting input terminal of operational amplifier D1B. The output terminal of operational amplifier D1B is connected to capacitor C11 and the first terminal of resistor R16. The inverting input terminal of operational amplifier D1B is connected to the first terminal of resistor R15 and... The second terminal of resistor R16; the second terminal of resistor R15 is connected to analog ground AGND; the second terminal of capacitor C11 is connected to the first terminal of resistor R14 and the negative input terminal of comparator D2; the second terminal of resistor R14 is connected to analog ground AGND; the comparison threshold Vref is set through the positive input terminal of comparator D2, and the output terminal of comparator D2 outputs a square wave signal to the microcontroller; the microcontroller corrects the PWM signal in real time according to the received multi-channel square wave signals and temperature feedback signals, thereby adjusting the heating temperature to perform different temperature compensations on each thermoluminescent sheet, so that the overall sample combination is always in the optimal working state.

[0016] Preferably, the control logic of the microcontroller is as follows: first, calculate the cumulative CPS value of each channel during the acquisition period. CPS累积 Then calculate CPS 累积 Average CPS value CPS AVG Next, the relative error of each channel was calculated. Determine the relative error I Whether it is within the preset range, if there is a relative error I For channels exceeding the preset range, adjust the target temperature of the abnormal channel, correct the corresponding PWM signal, and perform further judgment and correction until the relative error of all channels is corrected. I All requirements are met.

[0017] Preferably, the preset range is ±10%.

[0018] Preferably, the heating device further includes a mounting base, the heating element is disposed on the mounting base, and a pressure plate is disposed on the side of the temperature detection unit away from the mounting base. The pressure plate is fixed to the mounting base by a plurality of screws. The mounting base is made of heat-insulating material.

[0019] Preferably, the heating element is a ceramic heating element, and the temperature detection unit is a platinum resistance thermometer.

[0020] Preferably, four thermoluminescent sheets, four photomultiplier tubes, four heating elements, and four temperature detection units are provided.

[0021] The beneficial effects of this invention are:

[0022] 1) By adding a temperature calibration function, the problem of large system measurement error caused by the deviation between the actual heating temperature of the thermoluminescent sheet and the controlled heating temperature due to metal oxidation or changes in the assembly state of the temperature sensor has been optimized, thus improving the reliability of the system measurement.

[0023] 2) By using an intelligent control module to calculate and compare the cumulative count rate (CPS) values ​​of multiple channels in real time, the system can accurately sense whether the actual temperature of each thermoluminescent sheet meets the standard. When an abnormal CPS value of a certain channel is detected due to insufficient heating, the system can automatically adjust the temperature setpoint of that channel and dynamically control the heating circuit through a PWM signal to achieve precise temperature compensation. This closed-loop calibration mechanism based on measurement result feedback ensures effective correction of temperature drift caused by uncontrollable factors such as metal oxidation and changes in the heating state of platinum resistance thermometers. This fundamentally guarantees that each reading is taken at the optimal temperature, thereby greatly improving the accuracy and reliability of dose measurement results.

[0024] 3) This invention utilizes multiple thermoluminescent plates to increase the sample throughput in a single measurement. More importantly, the intelligent control module performs consistency calibration on multiple channels, eliminating inherent temperature differences between channels and ensuring that all samples are measured under highly consistent temperature conditions. This avoids systematic errors caused by uneven temperature fields between channels, providing a solid foundation for accurate comparison of batch samples and improving the consistency of overall measurement results.

[0025] 4) In the temperature detection circuit, differential-mode and common-mode filters were designed to effectively suppress interference and ensure that the temperature signal acquired by the platinum resistance thermometer is pure and accurate. In the signal processing circuit, the weak pulse current signal generated by the photomultiplier tube is converted into a regular square wave signal (CPS_PLUS) through I / V conversion, amplification, high-pass filtering, and comparator circuits, facilitating accurate counting by the microcontroller. The optimized design of these underlying circuits provides high-quality, low-noise input data for the upper-level intelligent calibration, which is the fundamental guarantee for the entire system to achieve high-precision calibration. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the device principle of the present invention;

[0027] Figure 2 Here is a diagram of the sample assembly structure;

[0028] Figure 3 This is a diagram of a photomultiplier tube assembly structure;

[0029] Figure 4 This is a structural diagram of the heating device;

[0030] Figure 5 This is a schematic diagram of a temperature detection and heating control circuit.

[0031] Figure 6 This is a schematic diagram of a signal processing and intelligent control circuit.

[0032] Figure 7 This is a flowchart of the microcontroller control logic. Detailed Implementation

[0033] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] See Figures 1-7The present invention provides a technical solution: a temperature calibration device for a thermoluminescence measurement system, comprising a sample assembly, wherein the sample assembly is connected to a photomultiplier tube assembly, the photomultiplier tube assembly is connected to an intelligent control module, the intelligent control module is connected to a heating device, and the heating device is connected to the sample assembly;

[0035] The sample assembly includes multiple thermoluminescent sheets, which are respectively arranged in multiple assembly areas separated by heat insulation material in the assembly groove, so as to realize independent heating of each thermoluminescent sheet.

[0036] The photomultiplier tube assembly includes multiple photomultiplier tubes, each configured to receive light signals emitted by a thermoluminescent sheet and convert the light signals into pulse signals; the pulse signals are output to the intelligent control module via a connector.

[0037] The intelligent control module includes a temperature detection and heating control circuit and a signal processing and intelligent control circuit. It is used to calculate the cumulative CPS value and average CPS value of each thermoluminescent sheet according to the pulse signal, thereby calculating the relative error of each thermoluminescent sheet, and generating a heating control signal based on the relative error and outputting it to the heating device to adjust the heating temperature to perform different temperature compensations on each thermoluminescent sheet, so that the overall sample combination is always in the optimal working state.

[0038] The heating device is used to heat each thermoluminescent sheet according to the heating control signal. It includes multiple heating sheets, each of which is equipped with a temperature detection unit. The heating sheet and the temperature detection unit are connected to a temperature detection and heating control circuit.

[0039] In this embodiment, the working principle is as follows: the heating device heats the sample assembly (containing 4 thermoluminescent wafers), and the sample assembly emits light; the light emitted by the sample assembly is received by the photomultiplier tube assembly (containing 4 photomultiplier tubes); the photomultiplier tube assembly converts the received light signal into a pulse current signal; the pulse current signal is transmitted to the signal control circuit; the signal control circuit performs I / V conversion and amplification of the pulse current signal, and simultaneously converts the pulse voltage signal into a square wave signal through a comparator; the microcontroller calculates the CPS value of the square wave signal and accumulates it in the reading device; it determines whether the CPS values ​​of the 4 channels are abnormal; if abnormal, the microcontroller changes the target value of the TEMP-PT1000A of the abnormal channel, thus changing its actual temperature; the actual heating temperature is changed by controlling the frequency of the PWM signal; the thermoluminescent wafer assembly is heated again to confirm whether the data is abnormal; the above steps are repeated until the data is normal.

[0040] In some embodiments, a pressure plate is provided on the side of the thermoluminescent sheet away from the assembly groove, and the pressure plate is fixed to the assembly groove by screws.

[0041] In this embodiment, as Figure 2 As shown, the sample assembly includes four thermoluminescent wafers, an assembly slot, a pressure plate, and screws. The four thermoluminescent wafers are assembled into the assembly slot, and the pressure plate is fixed to the assembly slot with screws. The bottom of the assembly slot is made of stainless steel, and the bottom area is divided into four sections by heat-insulating material, allowing the four thermoluminescent wafers to be heated independently without affecting each other.

[0042] In some embodiments, the photomultiplier tube assembly further includes a metal casing for shielding the photomultiplier tube from light.

[0043] In this embodiment, as Figure 3 As shown, the photomultiplier tube assembly includes four photomultiplier tubes, a metal casing, and connectors. Each of the four photomultiplier tubes receives light signals emitted from four thermoluminescent sheets. The metal casing is used for light shielding of the photomultiplier tubes. The connectors are used to extract the pulse signals generated by the photomultiplier tubes.

[0044] In some embodiments, the temperature detection and heating control circuit includes resistors R1, R2, R3, R4, R5, R6, R7, R8, and R9; capacitors C1, C2, C3, and C4; an instrumentation amplifier D1; a thyristor optocoupler U1; a thyristor Q1; and a field-effect transistor Q2. Specifically, capacitors C1, C2, and C4, resistors R2 and R4 form a first-order common-mode interference low-pass filter; instrumentation amplifier D1 and resistor R1 form an amplifier circuit; resistor R3 and capacitor C3 form a first-order differential-mode interference low-pass filter; and resistors R5, R6, R7, R8, and R9, the field-effect transistor Q2, the thyristor optocoupler U1, and the thyristor Q1 form a heating control circuit.

[0045] The first ends of resistors R2 and R4 are connected to the temperature detection unit. The second end of resistor R2 is connected to the positive input terminal of instrumentation amplifier D1, and the first ends of capacitors C1 and C2. The second end of resistor R4 is connected to the second end of capacitor C2, the first end of capacitor C4, and the negative input terminal of instrumentation amplifier D1. The second ends of capacitors C1 and C4 are connected to ground (GND). Pin 8 of instrumentation amplifier D1 is connected to the first end of resistor R1, and the second end of resistor R1 is connected to pin 1 of instrumentation amplifier D1. The output terminal of instrumentation amplifier D1 is connected to the first end of resistor R3. The second end of resistor R3 is connected to the first end of capacitor C3 and the microcontroller, outputting the temperature feedback signal to the microcontroller. The second end of capacitor C3 is connected to ground (GND).

[0046] The first terminal of resistor R7 receives the PWM signal, and the second terminal of resistor R7 is connected to the first terminal of resistor R9 and the gate of MOSFET Q2. The drain of MOSFET Q2 is connected to pin 2 of SCR optocoupler U1, and the source of MOSFET Q2 and the second terminal of resistor R9 are connected to ground (GND). Pin 1 of SCR optocoupler U1 is connected to the first terminal of resistor R5, pin 4 of SCR optocoupler U1 is connected to pin 3 of SCR Q1 and the first terminal of resistor R8, and pin 6 of SCR optocoupler U1 is connected to the first terminal of resistor R6. The second terminal of resistor R5 is connected to the power supply. The second terminal of resistor R6 is connected to the 220VAC live wire and pin 2 of SCR Q1. Pin 1 of SCR Q1 is connected to the second terminal of resistor R8 and the first terminal of heating element. The second terminal of heating element is connected to the 220VAC neutral wire.

[0047] In this embodiment, as Figure 5 As shown, to detect the temperature of the ceramic heating element, the two ends of the platinum resistance thermometer PT1000 are connected to PT1000+ and PT1000-. To reduce the influence of differential-mode and common-mode interference on the voltage U across the platinum resistance thermometer PT1000, a first-order low-pass filter for differential-mode and common-mode interference is designed. The first-order low-pass filter for common-mode interference includes capacitors C1, C2, and C4, and resistors R2 and R4. Capacitors C1 and C4 have the same capacitance, and resistors R2 and R4 have the same resistance value and are equal to... R Differential mode interference cutoff frequency Common-mode interference cutoff frequency To amplify the voltage across the platinum resistance thermometer PT1000, an amplifier circuit is designed, comprising an instrumentation amplifier D1 and a resistor R1. The amplification factor A = 49.4kΩ / R1+1, and the output voltage U1 at pin 6 of the instrumentation amplifier D1 = A•U. To reduce the impact of differential-mode interference on the signal, a first-order low-pass filter for differential-mode interference is designed, including a resistor R3 and a capacitor C3, with a cutoff frequency of... .

[0048] A PWM wave is used to control the conduction of the SCR optocoupler, further controlling the conduction time of the 220VAC circuit, thereby controlling the temperature of the ceramic heating element. Resistors R5, R6, R7, R8, and R9, along with MOSFET Q2, SCR optocoupler U1, and SCR Q1, form the heating control circuit. When the PWM wave is high, MOSFET Q2 conducts, and pins 1 and 2 of SCR optocoupler U1 are forward-biased, causing pins 4 and 6 of SCR optocoupler U1 to conduct at the zero point of the 220VAC circuit. The 220VAC voltage is divided by resistors R6 and R8, causing SCR Q1 to conduct, and the 220VAC is directly applied to the ceramic heating element, achieving heating. When the 220VAC crosses zero, SCR Q1 is cut off. A high PWM wave is required to trigger SCR Q1 to conduct again.

[0049] In some embodiments, the signal processing and intelligent control circuit includes resistors R11, R12, R13, R14, R15, and R16, capacitor C11, operational amplifier D1A, operational amplifier D1B, comparator D2, and a microcontroller; wherein resistors R11, R12, and operational amplifier D1A form an I / V conversion circuit, resistors R13, R15, and R16 and operational amplifier D1B form a non-inverting amplifier, and capacitor C11 and resistor R14 form a first-order high-pass filter;

[0050] The first terminal of resistor R12 receives the pulse signal output by the photomultiplier tube assembly. The second terminal of resistor R12 is connected to the inverting input terminal of operational amplifier D1A and the first terminal of resistor R11. The output terminal of operational amplifier D1A is connected to the second terminal of resistor R11 and the first terminal of resistor R13. The non-inverting input terminal of operational amplifier D1A is connected to analog ground AGND. The second terminal of resistor R13 is connected to the non-inverting input terminal of operational amplifier D1B. The output terminal of operational amplifier D1B is connected to capacitor C11 and the first terminal of resistor R16. The inverting input terminal of operational amplifier D1B is connected to the first terminal of resistor R15 and... The second terminal of resistor R16; the second terminal of resistor R15 is connected to analog ground AGND; the second terminal of capacitor C11 is connected to the first terminal of resistor R14 and the negative input terminal of comparator D2; the second terminal of resistor R14 is connected to analog ground AGND; the comparison threshold Vref is set through the positive input terminal of comparator D2, and the output terminal of comparator D2 outputs a square wave signal to the microcontroller; the microcontroller corrects the PWM signal in real time according to the received multi-channel square wave signals and temperature feedback signals, thereby adjusting the heating temperature to perform different temperature compensations on each thermoluminescent sheet, so that the overall sample combination is always in the optimal working state.

[0051] In this embodiment, as Figure 6As shown, the pulse signal generated by the photomultiplier tube combination is input to the PLUS. To convert the pulse current signal into a pulse voltage signal, an I / V conversion circuit is designed, including resistors R11 and R12, and operational amplifier D1A. Resistor R12 is used for impedance matching. Assuming the current value of the PLUS is I, after passing through the I / V conversion circuit, the output voltage U at pin 1 of D1A is U = I•R11. To amplify the voltage value, a non-inverting amplifier is designed, including resistors R13, R15, and R16, and operational amplifier D1B. The amplification factor A = 1 + R16 / R15. The 7-pin D1B... The output voltage U1 = A•U is set at the pin. A first-order high-pass filter is designed to filter out DC signals, including capacitor C11 and resistor R14. A comparator circuit is designed to convert the pulse voltage signal into a square wave signal, including comparator D2. The comparison threshold Vref is set, and the output square wave signal is CPS_PLUS. Four output square wave signals CPS_PLUS1, CPS_PLUS2, CPS_PLUS3, and CPS_PLUS4 and four output temperature signals TEMP-PT1000A-1, TEMP-PT1000A-2, TEMP-PT1000A-3, and TEMP-PT1000A-4 are input to the microcontroller. The microcontroller outputs four temperature control signals PWM1, PWM2, PWM3, and PWM4.

[0052] In some embodiments, the control logic of the microcontroller is as follows: first, calculate the cumulative CPS value of each channel during the acquisition period. CPS 累积 Then calculate CPS 累积 Average CPS value CPS AVG Next, the relative error of each channel was calculated. Determine the relative error I Whether it is within the preset range, if there is a relative error I For channels exceeding the preset range, adjust the target temperature of the abnormal channel, correct the corresponding PWM signal, and perform further judgment and correction until the relative error of all channels is corrected. I All requirements are met.

[0053] In this embodiment, as Figure 7 As shown, the microcontroller first calculates the cumulative CPS values ​​of the four channels during the acquisition period, and then calculates the average of the four cumulative CPS values. CPS AVG Calculate the relative error of each channel value. Determine relative error IWhether it is within ±10%; if there are channels exceeding the error range, the software needs to change the temperature corresponding to the target value of the TEMP-PT1000A for the channel. In actual testing, due to the attachment on the surface of the ceramic sheet or the loosening of the structure of the platinum resistance under long-term high temperature, the actual heating temperature of the thermoluminescent sheet will decrease. Therefore, the target value of TEMP-PT1000A needs to be increased to further increase its actual corresponding temperature value. In order to actually increase the temperature value of the ceramic heating sheet, the frequency of the control signal PWM wave needs to be increased. In order to confirm whether the control signal PWM is reasonable, the cumulative CPS value of the four channels within the acquisition time period needs to be calculated again by the microcontroller, and the relative error of each channel value needs to be calculated until it meets the requirements.

[0054] In some embodiments, the preset range is ±10%.

[0055] In some embodiments, the heating device further includes a mounting base, the heating element is disposed on the mounting base, and a pressure plate is disposed on the side of the temperature detection unit away from the mounting base, the pressure plate being fixed to the mounting base by a plurality of screws; the mounting base is made of heat-insulating material.

[0056] In this embodiment, as Figure 4 As shown, the heating device consists of four ceramic heating elements, a mounting base, a platinum resistance thermometer, a pressure plate, and screws. The four ceramic heating elements are primarily used for the independent heating of the four thermoluminescent plates. The mounting base is mainly used for mounting the four ceramic heating elements; it employs heat-insulating material to reduce heat conduction and improve the heat utilization efficiency of the ceramic heating elements. The platinum resistance thermometer is mainly used to detect the temperature of the four ceramic heating elements. The pressure plate is fixed to the mounting base with screws.

[0057] In some embodiments, the heating element is a ceramic heating element, and the temperature detection unit is a platinum resistance thermometer.

[0058] In some embodiments, four thermoluminescent sheets, four photomultiplier tubes, four heating elements, and four temperature detection units are provided.

[0059] The above description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the concept described herein through the above teachings or related technologies or knowledge. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A temperature calibration apparatus for a thermoluminescence measurement system, characterized by: The sample combination is connected with a photomultiplier combination, the photomultiplier combination is connected with an intelligent control module, the intelligent control module is connected with a heating device, and the heating device is connected with the sample combination. The sample combination comprises a plurality of thermoluminescence sheets arranged in a plurality of assembly areas in the assembly groove and separated by a heat insulation material, so as to realize independent heating of each thermoluminescence sheet. The photomultiplier combination comprises a plurality of photomultipliers configured to receive light signals emitted by each thermoluminescence sheet and convert the light signals into pulse signals, and the pulse signals are output to the intelligent control module through a connector. The intelligent control module comprises a temperature detection and heating control circuit and a signal processing and intelligent control circuit, which is used for calculating the cumulative CPS value and the average CPS value of each thermoluminescence sheet according to the pulse signal, calculating the relative error of each thermoluminescence sheet, and generating a heating control signal based on the relative error and outputting the heating control signal to the heating device to adjust the heating temperature and perform different temperature compensation for each thermoluminescence sheet, so that the overall sample combination is always in an optimal working state. The heating device is used for heating each thermoluminescence sheet according to the heating control signal, and comprises a plurality of heating sheets, each of which is provided with a temperature detection unit, and the heating sheet and the temperature detection unit are connected with the temperature detection and heating control circuit.

2. The temperature calibration apparatus for a thermoluminescence measurement system according to claim 1, characterized by: The thermoluminescence sheet is provided with a pressing sheet on the side away from the assembly groove, and the pressing sheet is fixed on the assembly groove by a screw.

3. The temperature calibration apparatus for a thermoluminescence measurement system according to claim 1, characterized by: The photomultiplier combination further comprises a metal cover for light shielding treatment of the photomultiplier.

4. The temperature calibration apparatus for a thermoluminescence measurement system according to claim 1, characterized by: The temperature detection and heating control circuit comprises resistors R1, R2, R3, R4, R5, R6, R7, R8, R9, capacitors C1, C2, C3, C4, an instrument amplifier D1, a silicon controlled photocoupler U1, a silicon controlled Q1 and a field effect tube Q2; wherein the capacitors C1, C2, C4, the resistor R2 and the resistor R4 constitute a common mode interference first-order low-pass filter, the instrument amplifier D1 and the resistor R1 constitute an amplification circuit, the resistor R3 and the capacitor C3 constitute a differential mode interference first-order low-pass filter, the resistors R5, R6, R7, R8, R9, the field effect tube Q2, the silicon controlled photocoupler U1 and the silicon controlled Q1 constitute a heating control circuit. The first end of the resistance R2 and the resistance R4 is connected with the temperature detection unit, the second end of the resistance R2 is connected with the positive input end of the instrument amplifier D1, the first end of the capacitor C1 and the capacitor C2; the second end of the resistance R4 is connected with the second end of the capacitor C2, the first end of the capacitor C4 and the negative input end of the instrument amplifier D1; the second end of the capacitor C1 and the capacitor C4 is connected with the ground GND; the pin 8 of the instrument amplifier D1 is connected with the first end of the resistance R1, the second end of the resistance R1 is connected with the pin 1 of the instrument amplifier D1; the output end of the instrument amplifier D1 is connected with the first end of the resistance R3, the second end of the resistance R3 is connected with the first end of the capacitor C3 and the single-chip microcomputer, and the temperature feedback signal is output to the single-chip microcomputer; the second end of the capacitor C3 is connected with the ground GND; The first end of the resistance R7 receives the PWM signal, and the second end of the resistance R7 is connected with the first end of the resistance R9 and the gate of the field effect transistor Q2; the drain of the field effect transistor Q2 is connected with the pin 2 of the silicon controlled photocoupler U1, and the source of the field effect transistor Q2 and the second end of the resistance R9 are connected with the ground GND; the pin 1 of the silicon controlled photocoupler U1 is connected with the first end of the resistance R5, the pin 4 of the silicon controlled photocoupler U1 is connected with the pin 3 of the silicon controlled Q1 and the first end of the resistance R8, and the pin 6 of the silicon controlled photocoupler U1 is connected with the first end of the resistance R6; the second end of the resistance R5 is connected with the power supply; the second end of the resistance R6 is connected with the live wire of 220VAC and the pin 2 of the silicon controlled Q1; the pin 1 of the silicon controlled Q1 is connected with the second end of the resistance R8 and the first end of the heating sheet; and the second end of the heating sheet is connected with the zero line of 220VAC.

5. The temperature calibration apparatus for a thermoluminescence measurement system according to claim 1, characterized by: The signal processing and intelligent control circuit comprises resistance R11, resistance R12, resistance R13, resistance R14, resistance R15, resistance R16, capacitor C11, operational amplifier D1A, operational amplifier D1B, comparator D2 and single-chip microcomputer; wherein the resistance R11, the resistance R12 and the operational amplifier D1A constitute an I / V conversion circuit, the resistance R13, the resistance R15, the resistance R16 and the operational amplifier D1B constitute a non-inverting amplifier, and the capacitor C11 and the resistance R14 constitute a first-order high-pass filter. The first end of the resistor R12 receives the pulse signal of the combination output of the photomultiplier, and the second end of the resistor R12 is connected to the inverting input end of the operational amplifier D1A and the first end of the resistor R11; the output end of the operational amplifier D1A is connected to the second end of the resistor R11 and the first end of the resistor R13, and the non-inverting input end of the operational amplifier D1A is connected to the analog ground AGND; the second end of the resistor R13 is connected to the non-inverting input end of the operational amplifier D1B; the output end of the operational amplifier D1B is connected to the first end of the capacitor C11 and the resistor R16, and the inverting input end of the operational amplifier D1B is connected to the first end of the resistor R15 and the second end of the resistor R16; the second end of the resistor R15 is connected to the analog ground AGND; the second end of the capacitor C11 is connected to the first end of the resistor R14 and the negative input end of the comparator D2; the second end of the resistor R14 is connected to the analog ground AGND; the positive input end of the comparator D2 is set to a comparison threshold Vref, and the output end of the comparator D2 outputs a square wave signal to the single-chip microcomputer; the single-chip microcomputer corrects the PWM signal in real time according to the received multi-channel square wave signal and the temperature feedback signal, so as to adjust the heating temperature to perform different temperature compensation on each thermoluminescence sheet, so that the overall sample combination is always in an optimal working state.

6. The temperature calibration apparatus for a thermoluminescence measurement system according to claim 5, characterized by: The control logic of the single-chip microcomputer is: firstly, the accumulated CPS values of each channel in the collection period are calculated CPS 累积 ; then the average CPS values of CPS 累积 are calculated CPS AVG ; then the relative errors of each channel are calculated , and whether the relative errors I are within the preset range is judged; if there is a channel whose relative error I exceeds the preset range, the target temperature of the abnormal channel is adjusted, the corresponding PWM signal is corrected, and the re-judgment and correction are performed until the relative errors of all channels I meet the requirements.

7. The temperature calibration apparatus for a thermoluminescence measurement system according to claim 6, characterized by: The preset range is ±10%.

8. The temperature calibration apparatus for a thermoluminescence measurement system according to claim 1, characterized by: The heating device further comprises a mounting base, the heating sheet is arranged on the mounting base, a crimping sheet is arranged on the side away from the mounting base of the temperature detection unit, and the crimping sheet is fixed on the mounting base through a plurality of screws; and the mounting base is made of a heat insulation material.

9. The temperature calibration apparatus for a thermoluminescence measurement system according to claim 1, characterized by: The heating sheet is a ceramic heating sheet, and the temperature detection unit is a platinum resistance.

10. The temperature calibration device for a thermoluminescence measurement system according to any one of claims 1 to 9, characterized in that: The thermoluminescence sheet, the photomultiplier, the heating sheet and the temperature detection unit are all arranged in four.

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