A Passive Calibration Method, System, Device and Product for a Scintillator Detector

Abstract

The present invention provides a passive calibration method, system, device and product for a scintillator detector, relating to the field of radiation detection. The method includes: using the scintillator detector to detect a reference radiation source to obtain a corresponding reference counting rate; replacing the reference radiation source with a reference light source, and using the scintillator detector to detect the reference light source multiple times to obtain corresponding multiple light source counting rates; determining a reference calibration coefficient of the scintillator detector under a first reference voltage and the condition of the reference radiation source according to the reference counting rate and the radioactivity of the reference radiation source; determining calibration coefficients of the scintillator detector under multiple different voltage conditions according to the proportional relationship between the multiple light source counting rates and the reference calibration coefficient. This method can use the reference light source to replace the use of the radiation source to calibrate the scintillator detector, so as to achieve the effect of passive calibration.

Description

Technical Field

[0001] The present invention relates to the field of radiation detection, and in particular, to a passive calibration method, system, device and product for a scintillator detector. Background Art

[0002] A scintillator detector is one of the key devices in the field of radiation detection. Generally, a scintillator detector includes a photomultiplier tube and a scintillator (which can also be called a scintillator crystal). The working principle of a scintillator detector is that rays interact with the scintillator, causing the scintillator atoms to be excited and release visible light or near-ultraviolet light when de-exciting. Subsequently, it is received by the photomultiplier tube and converted into an electrical signal, and finally the detection of radioactive rays is completed after processing. Among them, a photomultiplier tube is a vacuum optoelectronic device, and its working principle is based on the theories of the photoelectric effect, secondary electron emission, and electron optics. Its working process is: photons incident on the photocathode generate photoelectrons, and the photoelectrons enter the secondary emission multiplier through the electron optical input system, the number of electrons is multiplied, and finally the anode collects electrons to form an anode current or voltage signal.

[0003] The detection efficiency of a scintillator detector is relatively high and the response speed is fast. Moreover, the scintillator detector needs to be calibrated in advance during use. At present, the calibration process of the scintillator detector needs to rely on a metrology institute, and a large dose of radioactive source needs to be used for calibration multiple times. That is to say, currently, a known radioactive source is used to calibrate the detection performance of the scintillator detector. For example, after calibrating the scintillator detector by using standard sources such as cobalt-60 and cesium-137 and drawing an energy calibration curve by correlating the pulse amplitude of the standard source with the known energy, the calibrated scintillator detector is then used to detect an unknown radioactive source. Summary of the Invention

[0004] In view of this, an object of the present invention is to provide a passive calibration method, system, device and product for a scintillator detector, which can use a reference light source to calibrate the scintillator detector instead of using a radioactive source, so as to achieve the effect of passive calibration, and further reduce the contact between people and the radioactive source, improve the calibration efficiency and reduce the harm to the human body.

[0005] In order to achieve the above object, the technical solutions adopted in the embodiments of the present invention are as follows:

[0006] In a first aspect, the present invention provides a passive calibration method for a scintillator detector, the method comprising: detecting a reference radiation source using the scintillator detector to obtain a corresponding reference count rate; wherein, when detecting the reference radiation source, the working voltage of the scintillator detector is set to a first reference voltage; replacing the reference radiation source with a reference light source, and using the scintillator detector to detect the reference light source multiple times to obtain a corresponding plurality of light source count rates; wherein, the brightness value of the reference light source is set to a fixed value during the detection process of the scintillator detector, and when detecting the reference light source multiple times, the working voltage of the scintillator detector is sequentially set to a plurality of different voltages, and the plurality of different voltages includes the first reference voltage; determining a reference calibration coefficient of the scintillator detector under the conditions of the first reference voltage and the reference radiation source according to the reference count rate and the radioactivity of the reference radiation source; determining calibration coefficients of the scintillator detector under a plurality of different voltage conditions according to the proportional relationship between the plurality of light source count rates and the reference calibration coefficient.

[0007] In an alternative embodiment, the light source count rate corresponding to the first reference voltage among the plurality of light source count rates is the light source reference count rate; wherein, the step of determining calibration coefficients of the scintillator detector under a plurality of different voltage conditions according to the proportional relationship between the plurality of light source count rates and the reference calibration coefficient includes the following steps: determining the proportional relationship between the light source reference count rate and other light source count rates among the plurality of light source count rates; determining calibration coefficients of the scintillator detector under a plurality of different voltage conditions according to the proportional relationship and the reference calibration coefficient.

[0008] In an alternative embodiment, the radioactivity of the reference radiation source meets the requirements of an exempt source.

[0009] In an alternative embodiment, the numerical options for the first reference voltage include: the highest working voltage of the scintillator detector, and the numerical options for the minimum voltage among the plurality of different voltages include: the lowest working voltage of the scintillator detector.

[0010] In an alternative embodiment, the scintillator detector includes: a photomultiplier tube, a scintillator crystal, and a divider board; the light incident end of the photomultiplier tube is coupled to the coupling surface of the scintillator crystal, the voltage input end of the photomultiplier tube is connected to the divider board, and the divider board is connected to a control board; the reference light source includes a light emitting element, a support board, and a temperature sensor assembled together; wherein, the light emitting element and the temperature sensor are both arranged on the first board surface of the support board, and the board surface shape of the support board matches the shape of the detection end of the scintillator crystal, and the contact pins of the light emitting element and the contact pins of the temperature sensor are both arranged on the side of the first board surface.

[0011] In an alternative embodiment, during the process of detecting the reference light source by using the scintillator detector, the first plate surface is coupled to the detection end, and the light-emitting element and the temperature sensor are connected to the control board through their respective contact pins.

[0012] In an alternative embodiment, the method according to the first aspect further includes: detecting the reference light source by using the scintillator detector under a plurality of different temperature conditions to obtain a corresponding plurality of test count rates; wherein the brightness value of the reference light source is set to a fixed value during the detection process of the scintillator detector; determining a correction relationship between temperature and count rate according to the count differences between the plurality of different temperature conditions, the plurality of test count rates and a preset count standard value; and performing temperature compensation on the plurality of light source count rates by using the correction relationship between temperature and count rate.

[0013] In a second aspect, the present invention provides a passive calibration system for a scintillator detector, including: a control board, a scintillator detector, and a reference light source; the control board is configured to control the scintillator detector and the reference light source to implement the method according to any one of the embodiments in the first aspect.

[0014] In a third aspect, the present invention provides a passive calibration device for a scintillator detector, including a module configured to execute the method according to any one of the embodiments in the first aspect.

[0015] In a fourth aspect, the present invention provides a computer program product, including computer instructions, which, when running on a passive calibration device of a scintillator detector, cause the device to execute the method according to any one of the embodiments in the first aspect.

[0016] In a fifth aspect, the present invention provides a computer-readable storage medium, including instructions, which, when running on a passive calibration device of a scintillator detector, cause the passive calibration device of the scintillator detector to implement the method according to any one of the embodiments in the first aspect.

[0017] In the method described in the first aspect above, it can be understood that the content includes the following:

[0018] After obtaining the corresponding reference counting rate by using the reference radiation source, the reference radiation source is replaced with a reference light source to obtain the corresponding multiple light source counting rates. In this way, on the basis of reducing the usage times and duration of the radiation source (that is, the purpose can be achieved by only using the standard radiation source once), the reference light source can be used to replace the radiation source to realize the calibration coefficients of the scintillation detectors under multiple other voltages, and then complete the full-range calibration of the scintillation detectors within the entire voltage adjustment range. Among them, compared with the existing calibration methods, the embodiments of the present invention do not need to conduct experiments in the China Institute of Atomic Energy, which improves the efficiency of radiation source calibration. In summary, the embodiments of the present invention can use the reference light source to replace the radiation source to calibrate the scintillation detector, so as to achieve the effect of passive calibration, and then can reduce the contact between people and the radiation source, improve the calibration efficiency and reduce the harm to the human body.

[0019] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following specifically enumerates the embodiments of the present invention and, in conjunction with the accompanying drawings, makes a detailed description as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required to be used in the embodiments of the present invention. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0021] Figure 1 FIG. [X] is a schematic structural diagram of a passive calibration system for a scintillation detector provided by an embodiment of the present invention;

[0022] Figure 2 FIG. [Y] is another schematic structural diagram of a passive calibration system for a scintillation detector provided by an embodiment of the present invention;

[0023] Figure 3 FIG. [Z] is a schematic structural diagram of a reference light source provided by an embodiment of the present invention;

[0024] Figure 4 FIG. [W] is a schematic flowchart of a passive calibration method for a scintillation detector provided by an embodiment of the present invention;

[0025] Figure 5 FIG. [V] is a functional module diagram of a passive calibration device for a scintillation detector provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. Generally, the components of the embodiments of the present invention described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0027] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0028] It should be noted that similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0029] It should be noted that, without conflict, the features in the embodiments of the present invention can be combined with each other.

[0030] The embodiments of the present invention provide a technical solution, which includes: a passive calibration method, system, device, and product for a scintillation detector. The following will explain the technical solution provided by the present invention with reference to the accompanying drawings.

[0031] First, a passive calibration system for a scintillation detector provided by the embodiments of the present invention is introduced, which includes a scintillation detector and a reference light source.

[0032] In some embodiments, please refer to Figure 1 , Figure 1 which is a structural block diagram of a passive calibration system for a scintillation detector provided by the embodiments of the present invention. In Figure 1 , the passive calibration system 100 of the scintillation detector includes a scintillation detector and a reference light source 210. Among them, the scintillation detector includes a photomultiplier tube 110, a scintillation crystal 120, and a housing 140.

[0033] In some other possible embodiments, please refer to Figure 2 , Figure 2 which is another structural block diagram of a passive calibration system for a scintillation detector provided by the embodiments of the present invention. In Figure 2 , the passive calibration system of the scintillation detector includes: a scintillation detector, a reference light source 210, and a control board 150.

[0034] Among them, the scintillator detector includes: a photomultiplier tube 110, a scintillator crystal 120, a divider board 130, and a housing 140. Among them, the light incident end of the photomultiplier tube 110 is coupled to the coupling surface of the scintillator crystal 120, the voltage input end of the photomultiplier tube 110 is connected to the divider board 130, and the divider board 130 is connected to the control board 150.

[0035] The reference light source 210 includes: a support plate 211, a temperature sensor 212, and a light-emitting element 213 assembled together. Among them, the light-emitting element 213 and the temperature sensor 212 are both arranged on the first board surface of the support plate 211, and the shape of the board surface of the support plate 211 matches the shape of the detection end of the scintillator crystal 120. The contact pins of the light-emitting element 213 and the contact pins of the temperature sensor 212 are both arranged on the side of the first board surface of the support plate 211.

[0036] The control board 150 includes: a temperature sensor control module, a lamp control and signal acquisition module, and a high-voltage output module.

[0037] In the process of detecting the reference light source 210 by using the scintillator detector, the first board surface of the support plate 211 is coupled to the detection end of the scintillator crystal 120, and the light-emitting element 213 and the temperature sensor 212 are connected to the control board 150 through their respective contact pins.

[0038] In the above Figure 1 , Figure 2 :

[0039] The types of scintillator detectors can include sodium iodide (NaI) scintillator detectors, cesium iodide (CsI) scintillator detectors, etc., which can detect various rays, such as gamma rays, and convert the ray energy into visible light signals.

[0040] The reference light source 210 can provide a stable and adjustable standard light signal for the scintillator detector, which is used to simulate the light signal generated by the scintillator under the action of rays, so as to realize the passive scale calibration of the detector. Among them, the light-emitting element 213 can be, for example, a light-emitting diode (LED), and this is not limited.

[0041] In an alternative embodiment, the shape of the photomultiplier tube 110 is cylindrical, the top is the voltage input end (connected to the divider board 130), and the bottom is the light incident end. Optionally, in order to match the shape of the photomultiplier tube 110, the scintillator crystal 120 can be set to be cylindrical.

[0042] In the above Figure 1 or Figure 2 On this basis, please refer to Figure 3 , Figure 3A schematic structural diagram of a reference light source provided by an embodiment of the present invention. The reference light source may include: a support plate 211, a temperature sensor 212, a light-emitting element 213, a side 214, a contact pin 215, and a contact pin 216. The temperature sensor 212 is an optional component and is represented by a dashed line in the figure.

[0043] The side 214 may refer to a concentric circular area at the outermost periphery of the first plate surface of the support plate 211, and the shape can be referred to Figure 3 as shown.

[0044] The contact pin 215 and the contact pin 216 may be respectively set as the power-on pins (VCC, GND) of the light-emitting element 213. Figure 3 The contact pins of the temperature sensor 212 are not shown in the figure. In some possible embodiments, the contact pins of the temperature sensor 212 may also be set in the side 214 to facilitate the cooperative installation between the reference light source 210 and the scintillator crystal 120.

[0045] When both the photomultiplier tube 110 and the scintillator crystal 120 are set to be cylindrical, the shape of the support plate 211 may also be set to a matching cylindrical shape. Among them, the temperature sensor 212, the light-emitting element 213, the contact pin 215, and the contact pin 216 can all be set on the first plate surface of the support plate 211. This first plate surface can be used to couple with the detection end of the scintillator crystal 120, and the size and shape of the first plate surface can match that of the detection end, for example, they are the same in size and shape.

[0046] Among them, since the contact pins of the temperature sensor 212 and the light-emitting element 213 can both be located on the side 214 of the first plate surface, when installing and matching the reference light source 210 with the scintillator crystal 120, it is convenient for the connection between the temperature sensor 212 and the light-emitting element 213 and the control board 150.

[0047] In an optional embodiment, the reference light source 210 can be integrally encapsulated and the irradiation port of the light-emitting element 213 can be left by punching. Then, the first plate surface of the reference light source 210 can be coupled to the detection end (for example, in a bonding form of coupling). In this way, the reference light source 210 can be a whole cylinder without protruding positions, avoiding the problem of abnormal repeatability of test counting caused by the light source shaking due to the movement of slight external force.

[0048] Refer to the above Figure 1 、 Figure 2 、 Figure 3, during the process of implementing the method embodiment provided in this application, specifically during the process of using the scintillation detector to detect the reference light source 210 multiple times, the position of the reference light source 210 is set to remain fixed relative to the scintillation detector, so as to avoid scale deviation caused by the change of the position of the reference light source 210 affecting the illumination situation.

[0049] During the process of using the scintillation detector to detect the reference light source 210 multiple times, the temperature sensor 212 and the light-emitting element 213 can be connected to the control board 150 using their respective contact pins. In this way, the control board 150 can control the temperature sensor 212 and the light-emitting element 213, and control the photomultiplier tube 110 through the voltage dividing board 130, so as to implement the method embodiment provided in this application. More specifically, the temperature sensor module in the control board 150 can control the temperature sensor 212, the lamp control and signal acquisition module can control the reference light source 210 and implement the signal acquisition function, and the high-voltage output module can implement the power supply control for the voltage dividing board 130 and / or the reference light source 210. That is to say, Figure 2 , Figure 3 In this application embodiment, the respective signal terminals of the temperature sensor 212 and the light-emitting element 213 can be connected to the control board 150 to perform counting, temperature reading, and control of the lamp brightness.

[0050] Based on the passive calibration system of the scintillation detector provided above (including Figure 1 , Figure 2 , Figure 3 ), the embodiment of the present invention provides a passive calibration method for the scintillation detector, which can be applied to the passive calibration system of the above-mentioned scintillation detector. Among them, the passive calibration method of the scintillation detector can be executed by, for example, the control board 150 therein to achieve the effect of calibrating the scintillation detector using a reference light source instead of a radioactive source, achieving the effect of passive calibration.

[0051] Please refer to Figure 4 , Figure 4 , which is a schematic flowchart of a passive calibration method for a scintillation detector provided by an embodiment of the present invention. This method may include the following steps S110 - S140. The following will be described in sequence:

[0052] S110, use the scintillation detector to detect the reference radioactive source to obtain the corresponding reference count rate.

[0053] Specifically, the reference radioactive source can be placed at a predetermined position, and the scintillation detector is used to detect the reference radioactive source. And when detecting the reference radioactive source, the working voltage of the scintillation detector is set to the first reference voltage.

[0054] Optionally, the setting position of the reference radiation source can be set to be consistent with the position of the light-emitting element 213 in the reference light source 210. That is to say, when the scintillation detector performs detection, the position of the reference radiation source relative to the scintillation detector is consistent with the position of the light-emitting element 213 relative to the scintillation detector.

[0055] Optionally, the radioactivity of the reference radiation source meets the requirements of an exempt source. In other words, the type options of the reference radiation source include: exempt radiation source.

[0056] Among them, an exempt radiation source refers to a radiation source that is judged based on key elements such as the activity and radioactive concentration of radioactive substances. When the radiation hazard is extremely small, no special radiation protection measures need to be taken. This exemption situation is mostly applicable to situations where the activity and concentration of radioactive substances are extremely low, or the radiation source only involves short-term and short-distance exposure. For example, a Cs-137 source with an activity below 1*10^5 can be considered to meet the requirements of an exempt source and belongs to an exempt radiation source.

[0057] S120. Replace the reference radiation source with a reference light source, and use the scintillation detector to detect the reference light source multiple times to obtain corresponding multiple light source count rates.

[0058] This replacement can be understood as a position replacement. That is to say, after completing step S110, the reference radiation source can be removed, and then the reference light source is assembled with the scintillation detector. And before and after the replacement, the position of the reference radiation source relative to the scintillation detector is consistent with the position of the light-emitting element 213 relative to the scintillation detector.

[0059] Among them, the brightness value of the reference light source is set to a fixed value during the detection process of the scintillation detector, and during multiple detections of the reference light source, the working voltage of the scintillation detector is sequentially set to multiple different voltages, and the first reference voltage is included in the multiple different voltages.

[0060] The selection principle of the light-emitting element 213 in the reference light source is: according to the photomultiplier tube (PMT) used in the scintillation detector, the maximum sensitivity wavelength of the PMT currently used in radiation measurement is 420nm. Then, the light-emitting element 213 can be selected according to the purpose of the detector used. For example, the light wavelength of the light-emitting element 213 can be between 390nm and 420nm.

[0061] The multiple different voltages can be determined according to the range of the scintillation detector.

[0062] In some alternative embodiments, the numerical options of the first reference voltage include: the maximum operating voltage of the scintillation detector, or the first reference voltage can be set to the maximum operating voltage of the scintillation detector; the numerical options of the minimum voltage among the multiple different voltages include: the minimum operating voltage of the scintillation detector, or the minimum voltage among the multiple different voltages can be set to the minimum operating voltage of the scintillation detector.

[0063] Specifically, the multiple different voltages can be selected according to the recommended manual of the PMT used. Among them, the highest voltage among the multiple different voltages needs to be determined according to the manual to prevent damage to the PMT after setting it too high; there is no limit to the lowest voltage, and generally 200V can reach the upper limit of the range.

[0064] For example, the first reference voltage can be set to 1000V, and the multiple different voltages can be set in sequence as: 1000V, 800V, 600V, 400V, 200V.

[0065] In some alternative embodiments, the first reference voltage among the multiple different voltages is the highest voltage, or rather, the first reference voltage is the highest voltage among the multiple different voltages. The counting rate sensitivity of the scintillation detector is different at different operating voltages. As the operating voltage increases, the sensitivity of the scintillation detector will increase accordingly. Since the sensitivity of the scintillation detector is relatively high when the voltage is relatively high, by setting the first reference voltage as the highest voltage among the multiple different voltages, the reference radiation source can be selected as an exempt source (low dose rate) for calibration to obtain the reference calibration coefficient.

[0066] S130. Determine the reference calibration coefficient of the scintillation detector under the first reference voltage and the reference radiation source according to the reference counting rate and the radioactivity of the reference radiation source.

[0067] In an alternative embodiment, the calibration coefficient = the agreed true value / the counting rate. That is to say, the reference calibration coefficient of the scintillation detector under the first reference voltage and the reference radiation source is: the agreed true value of the reference radiation source / the reference counting rate.

[0068] S140. Determine the calibration coefficients of the scintillation detector under multiple different voltage conditions according to the proportional relationship between the multiple light source counting rates and the reference calibration coefficient.

[0069] Since there is a certain proportional relationship between the calibration coefficients at different voltages, when the calibration coefficient at one voltage is known, the calibration coefficients of the remaining voltages can be calculated according to the proportional relationship between the light source counting rates at different voltages. Then, further based on the reference calibration coefficient of the reference radiation source, the calibration coefficients at the remaining voltages can be obtained synchronously, thereby realizing the calibration at high doses.

[0070] In an alternative embodiment, the light source count rate corresponding to the first reference voltage among the multiple light source count rates can be denoted as the light source reference count rate. In this case, S140, determining the calibration coefficients of the scintillation detector under multiple different voltage conditions according to the proportional relationship between the multiple light source count rates and the reference scale coefficient may include the following steps S141 - S142:

[0071] Step S141, determining the proportional relationship between the light source reference count rate and other light source count rates among the multiple light source count rates.

[0072] Step S142, determining the calibration coefficients of the scintillation detector under multiple different voltage conditions according to the proportional relationship and the reference scale coefficient.

[0073] The following will take Table 1 as an example to illustrate the above steps S141 - S142:

[0074] Table 1 is a table of light source count rates and reference count rates under multiple voltage conditions. Among them, Table 1 records that the working voltage is at intervals of 200V, with the highest voltage (1000V) as the reference, and records the ratio between the count rates of the PMT at different voltages and the count rate at the highest voltage under the same reference light source. And the calibration conditions in Table 1 are: the reference radiation source is set as an exempt source, and the agreed true value of the exempt source is 10u.

[0075] Table 1

[0076]

[0077] The specific test process of the above Table 1 may include the following steps:

[0078] 1. Record the count rate of the exempt source (10u) at 1000V, and calculate the calibration coefficient (10 / 100 = 0.1).

[0079] 2. Record the count rate of the reference light source at 1000V, and calculate the corresponding agreed true value according to the calibration coefficient at 1000V.

[0080] 3. Record at intervals of 200V, and record the count rates of the same reference light source at each stage. Calculate the ratio of the count at each voltage segment to the count at 1000V, and then calculate the count values at each stage according to this ratio.

[0081] 4. Calculate the calibration coefficients of each voltage segment.

[0082] For example, the calibration coefficient at 800V = the ratio of the count rates under the voltage conditions of 1000V and 800V * the calibration coefficient at 1000V, and so on to calculate the calibration coefficients of all voltage segments. Among them, the assumed premise of Table 1 is the PMT working voltage range: 1000V - 200V.

[0083] The following is a detailed description:

[0084] According to Table 1, using the above step S110, the counting rate corresponding to 1000V (i.e., the reference counting rate) can be obtained as 100, so that the calibration coefficient (reference calibration coefficient) of the scintillation detector under the conditions of 1000V (the first reference voltage) and the exemption source can be determined as 10u / 100 = 0.1. Then, corresponding to the above step S141, the proportional relationships between the counting rates under the conditions of 1000V (reference light source), 800V, 600V, 400V, and 200V can be determined as follows: 2, 4, 40, 2000.

[0085] Furthermore, corresponding to the above step S142, based on the condition of 1000V, the calibration coefficient can be obtained with reference to the above reference calibration coefficient of 0.1; furthermore, according to the proportional relationships between the counting rates under the conditions of 1000V (reference light source) and other voltage conditions and this reference calibration coefficient, it can be calculated that: the calibration coefficient under the condition of 800V is 0.1 * 2 = 0.2; the calibration coefficient under the condition of 600V is 0.1 * 4 = 0.4; the calibration coefficient under the condition of 400V is 0.1 * 40 = 4; the calibration coefficient under the condition of 200V is 0.1 * 2000 = 2000. That is to say, the calibration coefficient under a certain voltage condition = the ratio of the reference counting rate of the light source to the counting rate of the light source under this voltage condition * the reference calibration coefficient.

[0086] Among them, the description of the above conventional true value is as follows: Fix the position of the scintillation detector, and the conventional true value of the exemption source can be considered the same under the condition of ensuring the same distance and position.

[0087] Since the brightness of the reference light source 210 is affected by temperature, different brightnesses will cause different counting rates and thus affect the measurement results. To solve this problem, optionally, on the basis of the provided method embodiment, the method may further include the following steps 1.1 - step 1.3 to perform temperature compensation and correct the influence of temperature on the reference light source 210. Figure 4 Based on the provided method embodiment, the method may further include the following steps 1.1 - step 1.3 to perform temperature compensation and correct the influence of temperature on the reference light source 210.

[0088] Step 1.1, under multiple different temperature conditions, use the scintillation detector to detect the reference light source 210 to obtain corresponding multiple test counting rates.

[0089] Among them, the brightness value of the reference light source 210 is set to a fixed value during the detection process of the scintillation detector.

[0090] Optionally, the ranges of multiple different temperature conditions here can be 10°C - 40°C. Also, at a certain temperature condition, the holding duration for detecting the reference light source 210 using the scintillation detector is preferably 4 h or longer, and the temperature data for the last 2 h is taken for the count rate data to ensure that the temperature of the probe is as constant as possible.

[0091] It can be understood that the brightness value setting of the reference light source 210 is achieved by adjusting its voltage / current. Therefore, setting the brightness value to a fixed value here can be understood as: fixing the voltage / current of the reference light source 210 to a certain value so that its brightness value is set to a fixed value. However, the actual brightness of the reference light source 210 is still affected by temperature.

[0092] Step 1.2: Determine the correction relationship between temperature and count rate according to the count differences between multiple different temperature conditions, multiple measured count rates, and the preset count standard value.

[0093] Among them, the count differences between multiple different temperature conditions, multiple measured count rates, and the preset count standard value can represent: the deviation values between the measured count rates obtained under multiple different temperature conditions and a preset standard count rate. The preset count standard value refers to the count rate that the scintillation detector should measure for the reference light source under normal temperature and constant temperature.

[0094] The following takes Table 2 as an example to explain Steps 1.1 and 1.2. Table 2 shows the measured count rates under different temperature conditions and the corresponding data.

[0095] Table 2

[0096]

[0097] According to Table 2, it can be determined that the count difference between the measured count rate corresponding to T1 and the preset count standard value is ΔCPS1 = Cps1 - cps_b1. In this way, using the data T1, T2, T3 in Table 2 and the corresponding ΔCPS1, ΔCPS2, ΔCPS3, the correction relationship between temperature and count rate can be determined (for example, determined by a fitting algorithm). Specifically, the correction relationship between temperature and count rate includes: the count difference between the measured count rate under a certain temperature condition and the preset count standard value.

[0098] In an optional embodiment, the correction relationship between temperature and count rate can be obtained by linear fitting. For example, ΔCPS = K * TP + B, where TP represents temperature, K and B are the values obtained by fitting, and ΔCPS represents the count difference between the measured count rate under the temperature condition TP and the preset count standard value.

[0099] Step 1.3: Perform temperature compensation on the counting rates of multiple light sources by using the corrected relationship between temperature and counting rate.

[0100] By using the corrected relationship between temperature and counting rate obtained in the above Step 1.2, temperature compensation can be performed on the counting rate of the light source. For example, assume that the counting rate CPS of a certain light source is collected under the temperature condition of TP. Then, the data of the counting rate CPS of this light source after temperature compensation is: CPS_t = CPS - (K * TP + B); where CPS_t represents the counting rate of the light source after temperature compensation, CPS represents the counting rate of the light source before temperature compensation, TP represents the temperature, and K and B are the values obtained by fitting.

[0101] It should be noted that this Step 1.3 can be executed during the execution of the above Step S120. Specifically, when using the scintillation detector to detect the reference light source multiple times and obtaining the corresponding multiple light source counting rates, Step 1.3 can be used to perform temperature compensation on the multiple light source counting rates and then output them.

[0102] Among them, since the temperature sensor 212 and the light-emitting element 213 are packaged together, the temperature change of the light-emitting element 213 can be accurately controlled.

[0103] In an alternative embodiment, the ranges of the multiple different temperature conditions in the above Steps 1.1 - 1.3 can be 10°C - 40°C. And, under a certain temperature condition, it is recommended that the holding duration for detecting the reference light source 210 by using the scintillation detector be 4 h or longer, and the temperature data of the last 2 h be taken for the counting rate data to ensure that the temperature of the probe is as constant as possible. In the above Steps 1.1 - 1.3, the brightness of the reference light source 210 is fixed so that its count remains at about 10000 cps. The test counting rate can be the average counting rate over a period of time.

[0104] It should be understood that in the above method embodiment, after obtaining the corresponding reference counting rate by using the reference radiation source, the reference radiation source is replaced with the reference light source 210 to obtain the corresponding multiple light source counting rates. In this way, on the basis of reducing the number of uses and the usage duration of the radiation source (that is, only using the standard radiation source once), the reference light source 210 can be used to replace the radiation source to implement the calibration coefficients of the scintillation detectors under other multiple voltages, and then complete the full-scale calibration of the scintillation detectors in the entire voltage adjustment range. In other words, the embodiment of the present invention can use the reference light source to replace the radiation source to calibrate the scintillation detector, so as to achieve the effect of passive calibration, and further reduce the contact between people and the radiation source, improve the calibration efficiency while reducing the harm to the human body.

[0105] In order to perform the corresponding steps in the above embodiments and various possible methods, a method for implementing a passive calibration device of a scintillator detector is given below. Figure 5 , Figure 5 The functional module diagram of a passive calibration device 300 of a scintillator detector provided in an embodiment of the present invention is shown. The passive calibration device 300 of the scintillator detector can be used to implement the above method embodiment. It should be noted that the basic principle and technical effect of the passive calibration device 300 of a scintillator detector provided in this embodiment are the same as those of the above embodiment. For the sake of brief description, for parts not mentioned in this embodiment, reference can be made to the corresponding contents in the above embodiment. The passive calibration device 300 of the scintillator detector may include: a transceiver module 310 and a processing module 320.

[0106] Optionally, the transceiver module 310 and the processing module 320 may be stored in a memory in the form of software or firmware or solidified in the memory provided by the present invention. Figure 2 The operating system (OS) of the control board 150 shown in the figure can be executed by the control board 150. Meanwhile, data and program codes required for executing the above units can be stored in the memory.

[0107] It is understandable that the transceiver module 310 and the processing module 320 can be used to support the control board 150 to perform the relevant steps in the above method embodiment, and / or other processes of the technology described herein, such as the above Figure 4 The method embodiments shown and the various method embodiments described above are not limited to this.

[0108] Of course, in an optional embodiment, the transceiver module 310 and the processing module 320 may also be adjusted and replaced by Figure 2 The temperature sensor control module, the light control and signal acquisition module, and the high voltage output module shown in the figure are used to perform the relevant steps in the above method embodiment and / or other processes used in the technology described in this article, such as the above Figure 4 The method embodiments shown and the various method embodiments described above are not limited to this.

[0109] Based on the above method embodiment, the embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the above method embodiment is executed. Specifically, the storage medium can be a general storage medium, such as a mobile disk, a hard disk, etc. When the computer program on the storage medium is executed, the method in the above embodiment can be executed.

[0110] Based on the above method embodiments, the present invention further provides a computer program product, including computer instructions, which can cause the device to execute as when the computer instructions run on the passive calibration device of the scintillation detector Figure 4 the method embodiments described above.

[0111] The above are only the embodiments of the present invention and are not intended to limit the protection scope of the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A passive calibration method for a scintillator detector, characterized in that: include: Detecting a reference radiation source using the scintillator detector to obtain a corresponding reference count rate; wherein the operating voltage of the scintillator detector is set to a first reference voltage when detecting the reference radiation source; The reference radiation source is replaced with a reference light source, and the reference light source is detected multiple times by the scintillator detector to obtain corresponding multiple light source count rates; wherein the brightness value of the reference light source is set to a constant value during the detection process of the scintillator detector, and the working voltage of the scintillator detector is sequentially set to multiple different voltages when the reference light source is detected multiple times, and the multiple different voltages include a first reference voltage; Determining a reference calibration coefficient of the scintillator detector under the conditions of the first reference voltage and the reference radiation source according to the reference count rate and the radioactivity of the reference radiation source; Determining the scale factor of the scintillator detector under multiple different voltage conditions according to the proportional relationship between the count rates of the multiple light sources and the reference scale factor; The light source count rate corresponding to the first reference voltage among the plurality of light source count rates is the light source reference count rate; Wherein, determining the scale factor of the scintillator detector under multiple different voltage conditions according to the proportional relationship between the count rates of the multiple light sources and the reference scale factor comprises the following steps: Determine a ratio between the light source reference count rate and other light source count rates among the plurality of light source count rates; The scale factor of the scintillator detector under a plurality of different voltage conditions is determined according to the ratio and the reference scale factor.

2. The passive calibration method of scintillator detector according to claim 1, characterized in that: The radioactivity of the reference radioactive source meets the requirements for exempted sources.

3. The passive calibration method of a scintillator detector according to claim 1, characterized in that: The numerical options of the first reference voltage include: the highest operating voltage of the scintillator detector, and the numerical options of the minimum voltage among the multiple different voltages include: the lowest operating voltage of the scintillator detector.

4. The passive calibration method of a scintillator detector according to claim 1, characterized in that: The scintillator detector comprises: a photomultiplier tube, a scintillator crystal, and a voltage divider plate; the light incident end of the photomultiplier tube is coupled to the coupling surface of the scintillator crystal, the voltage input end of the photomultiplier tube is connected to the voltage divider plate, and the voltage divider plate is connected to the control board; The reference light source includes a light-emitting element, a support plate, and a temperature sensor assembled together; wherein the light-emitting element and the temperature sensor are both arranged on a first plate surface of the support plate, and the plate surface shape of the support plate matches the shape of the detection end of the scintillator crystal, and the contact pins of the light-emitting element and the contact pins of the temperature sensor are both arranged on the side of the first plate surface of the support plate.

5. The passive calibration method of scintillator detector according to claim 4, characterized in that: In the process of detecting the reference light source by using the scintillator detector, the first board surface is coupled with the detection end, and the light emitting element and the temperature sensor are connected to the control board through their respective contact pins.

6. The passive calibration method of scintillator detector according to claim 4, characterized in that: The method further comprises: Under multiple different temperature conditions, the reference light source is detected by the scintillator detector to obtain multiple corresponding test count rates; wherein the brightness value of the reference light source is set to a constant value during the detection process of the scintillator detector; Determining a correction relationship between temperature and count rate according to the plurality of different temperature conditions, the plurality of test count rates and count differences between preset count standard values; The count rates of the multiple light sources are temperature compensated by utilizing the correction relationship between the temperature and the count rate.

7. A passive calibration system for a scintillator detector, characterized in that: include: Control board, scintillator detector and reference light source; The control board is used to control the scintillator detector and the reference light source to implement the method according to any one of claims 1 to 6.

8. A passive calibration device for a scintillator detector, characterized in that: The method comprises a module for executing the method as claimed in any one of claims 1 to 6.

9. A computer program product, characterized in that The invention comprises computer instructions, which, when being executed on a passive calibration device of a scintillator detector, cause the device to execute the method as claimed in any one of claims 1 to 6.

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