Radiation dose measurement device and method based on cesium copper iodide scintillator

Abstract

The present application relates to a kind of radiation dose measuring device and method, specifically, a kind of radiation dose measuring device and method based on cesium copper iodine scintillator.Solve the technical problems that the device is complex, technical requirement is high, not suitable for conventional dose measurement, cannot give the measurement result in real time and measurement result is susceptible to environmental influences such as air pressure, temperature, humidity in the commonly used gamma radiation dose technology.The radiation dose measuring device of the present application includes cesium copper iodine single crystal scintillator, photoelectric conversion device arranged on the light path of cesium copper iodine single crystal scintillator and the measurement unit connected with the electrical signal output end of photoelectric conversion device through signal cable;Cesium copper iodine single crystal scintillator is used to convert the energy deposited in it by gamma rays into fluorescent signal.The present application produces interaction and emits fluorescent signal by irradiating cesium copper iodine single crystal scintillator with gamma rays, photoelectric conversion device receives fluorescent signal and converts optical signal into electrical signal, and realizes the accurate measurement of gamma ray dose.

Description

TECHNICAL FIELD

[0001] The present application relates to a radiation dose measuring device and method, in particular to a radiation dose measuring device and method based on cesium copper iodine scintillator. BACKGROUND

[0002] Radiation dose refers to the energy (absorbed dose) imparted to matter or tissue by ionizing radiation. In theory, any effect produced in the irradiated material that has a definite relationship with the absorbed radiation energy can be used to determine the radiation dose, such as ionization, heating, luminescence (excitation), and various physical changes, such as oxidation-reduction, cleavage, polymerization, crosslinking, color change, viscosity change, and many other chemical changes or changes in the physical properties of the system caused thereby. Radiation dose includes exposure, specific energy release, absorbed dose, and dose equivalent, etc.

[0003] Commonly used methods for measuring gamma radiation dose mainly include calorimetric method, chemical method, ionization method and thermoluminescence method. The calorimetric method can directly measure the absorbed dose, and is suitable for making reference / standard devices, but the device system is complex, the technical requirements are high, and it is not suitable for routine dose measurement; the chemical method is a passive dose measurement method, which often uses aqueous solution system, has wide measurement range and high upper limit of measurement (up to the order of magnitude of 10,000 Gy), and is suitable for high dose measurement; the thermoluminescence method has high sensitivity, the measurement range spans 6-7 orders of magnitude, and the lower limit of measurement is μGy, which is mainly used for personal dose and environmental dose measurement, and is a passive measurement method, which cannot give real-time measurement results; the ionization method has high precision, good stability and easy operation, and is a general absorbed dose measurement method, which is often used as a standard in the field of radiotherapy and radiation protection, but the ionization chamber needs an external electric field, and is affected by environmental temperature / pressure.

[0004] Gamma radiation dose is generally divided into four grades of environmental grade, protection grade, treatment grade and processing grade according to the dose rate, and the dose rate range and parameters of different grades are shown in the following table:

[0005] Table 1 Photonic external exposure dose rate classification

[0006] Class Dose rate Basic quantity Calibration quantity In situ Environmental class 10 nGy / h ~ 10 mGy / h [00000D1] a ]]> D a ]]> [00000D3] a ]]> Protection class 10 μSv / h ~ 10 Sv / h K a ]]> H * (d), H'(d), H p (d)]]> H * (d), H'(d), H p (d)]]> Therapeutic class 10 mGy / h ~ 10 kGy / h K a ]]> K a , D w ]] K a , D w ]] Processing class 10 Gy / h ~ 10 MGy / h <![CDATA[D a ]]> <![CDATA[D a ]]> D a ]]>

[0007] In the prior art, the most commonly used device for measuring the therapeutic level of gamma dose rate is a graphite cavity ionization chamber, which has high sensitivity and high precision, and is often used as a standard measuring instrument for gamma radiation dose (treatment level). The graphite cavity ionization chamber measures the gamma ray dose based on the ionization effect of gas, and requires an external electric field to form a stable ionization current, with a high voltage of about ± 500 V. The disadvantage is that during measurement, the cavity is in communication with the environment, and the gas quality is affected by the ambient temperature and air pressure, so the measurement result needs to be corrected for ambient temperature / air pressure, making the measurement process complex, with high technical requirements, and the accuracy of the measurement result is easily affected. Research has found that low-dimensional (zero-dimensional, one-dimensional, two-dimensional, three-dimensional) halide perovskites have excellent characteristics of high effective atomic number and high light yield (more than 20,000 photons / MeV), and are expected to play a huge role in gamma dose monitoring. SUMMARY

[0008] The purpose of the present application is to solve the technical problems of the current commonly used gamma radiation dose measurement technology, such as complex device, high technical requirements, not suitable for routine dose measurement, unable to give real-time measurement results, and measurement results easily affected by environmental factors such as air pressure, temperature, and humidity, and to provide a radiation dose measurement device and method based on cesium copper iodine scintillator.

[0009] The concept of the present application is to use a large-size block of cesium copper iodine single crystal as a gamma ray scintillator, interact with gamma rays, achieve effective attenuation and energy absorption of gamma rays, and generate a fluorescence signal. The photoelectric conversion device is arranged on the light path of the cesium copper iodine single crystal scintillator, and the photoelectric effect of the photoelectric conversion device converts the light signal into an electrical signal, and then the measurement unit collects and records the electrical signal, realizing the measurement of gamma ray radiation dose.

[0010] The technical solution of the present application is:

[0011] A radiation dose measurement device based on a cesium copper iodine scintillator, characterized in that it comprises a cesium copper iodine single crystal scintillator, a photoelectric conversion device arranged on the light path of the cesium copper iodine single crystal scintillator, and a measurement unit connected to the electrical signal output end of the photoelectric conversion device through a signal cable.

[0012] The cesium copper iodine single crystal scintillator is used to convert the radiation dose of gamma rays into a fluorescence signal.

[0013] The cesium copper iodine single crystal scintillator is irradiated by gamma rays to produce interaction and emit a fluorescence signal, the photoelectric conversion device receives the fluorescence signal and converts it into an electrical signal, and the measurement unit records the electrical signal in the photoelectric conversion device.

[0014] Further, the photoelectric conversion device adopts a semiconductor heterojunction device or a photoelectric cell, and the semiconductor heterojunction device works in a self-powered mode with zero bias voltage, and the dose rate level of the radiation dose of the gamma rays is a therapeutic level or above;

[0015] Alternatively, the photoelectric conversion device adopts a photomultiplier tube, and the dose rate level of the radiation dose of the gamma rays is an environmental level or a protection level.

[0016] Further, the cesium copper iodine single crystal scintillator is an undoped cesium copper iodine single crystal Cs3Cu2I5 or a doped cesium copper iodine single crystal Cs3Cu2I5:X, X being a metal doping element.

[0017] Further, the doped cesium copper iodine single crystal scintillator is a Tl-doped cesium copper iodine single crystal Cs3Cu2I5:Tl or a Na-doped cesium copper iodine single crystal Cs3Cu2I5:Na.

[0018] Further, a shielding shell is further included, and the cesium copper iodine single crystal scintillator and the photoelectric conversion device are arranged in the shielding shell, and a through hole is arranged on the sidewall of the shielding shell for a signal cable to pass through.

[0019] Further, the cesium copper iodine single crystal scintillator is in close contact with the photoelectric conversion device.

[0020] Further, the measurement unit is any one of a table power supply, an electrometer, and an amplitude analyzer.

[0021] Further, the diameter of the cesium copper iodine single crystal scintillator is φ3-50 mm, and the thickness is 1-100 mm; and the size of the semiconductor heterojunction device is 3×3-50×50 mm. 2 .

[0022] A radiation dose measurement method based on a cesium copper iodine scintillator, based on the above-mentioned radiation dose measurement device based on a cesium copper iodine scintillator, and the special feature is that it comprises the following steps:

[0023] S1) Obtain the intercept and slope of the dose response linear function of the measurement device

[0024] S1.1) Install the measurement device, place the cesium copper iodine single crystal scintillator in a known dose rate gamma radiation field, turn on the gamma source, and irradiate the cesium copper iodine single crystal scintillator with gamma rays, and record the electrical signal through the measurement unit;

[0025] S1.2) After a set time, turn off the gamma source;

[0026] S1.3) Obtain the intercept a and the slope b by using the known dose rate and the corresponding electrical signal through the following formula:

[0027] y=a+bx

[0028] x is the dose rate, unit: Gy / h;

[0029] y is the current, unit: nA;

[0030] a and b are the intercept and slope of the dose response linear function, respectively;

[0031] S2) The cesium copper iodine single crystal scintillator is placed in the gamma radiation field of the radiation dose rate to be measured, the gamma source is turned on, the gamma rays irradiate the cesium copper iodine single crystal scintillator, and the electric signal is recorded by the measuring unit;

[0032] S3) After reaching the set time, the gamma source is turned off;

[0033] S4) The formula in step S1.3) and the intercept and slope are used to calculate the radiation dose rate to be measured by the electric signal obtained in step S2).

[0034] Compared with the prior art, the beneficial effects of the present application are:

[0035] 1、The measuring device of the present application adopts a cesium copper iodine single crystal with high luminous yield, has high energy conversion efficiency, and can realize high detection efficiency of gamma rays. In addition, the performance of core components such as the cesium copper iodine single crystal scintillator and the photoelectric conversion device is not affected by environmental temperature, humidity and air pressure, so that the gamma radiation dose measurement results of the device can be free from the influence of environmental temperature, humidity and air pressure.

[0036] 2、The measuring device of the present application selects a cesium copper iodine single crystal scintillator, which is safe, non-toxic and easy to use.

[0037] 3、The gamma radiation dose measuring device of the present application is composed of a cesium copper iodine single crystal scintillator, a photoelectric conversion device, a measuring unit and a signal cable, and has simple principle, compact structure, simple portability and low cost.

[0038] 4、The measuring device of the present application can realize gamma radiation dose measurement of different levels by selecting appropriate photoelectric conversion devices.

[0039] 5、The measuring device of the present application adopts a semiconductor heterojunction device when measuring the therapeutic level of gamma radiation dose, and works in a self-powered mode without external bias, which can realize high-efficiency photoelectric signal conversion, solve the problem of unstable sensitivity caused by external electric field, and further solve the problems of inaccurate measurement results and high energy consumption.

[0040] 6、The measuring device of the present application, when measuring the therapeutic level radiation dose, selects a gamma radiation dose detector composed of a semiconductor heterojunction device and cesium copper iodine (Cs3Cu2I5) scintillator, etc., can realize a large dynamic response range, the dark current is not higher than 3pA, the theoretical detection limit is lower than 10.2mGy / h, in the range of 10mGy / h-10kGy / h, the signal current of the measuring device is linearly responsive to the dose rate, the linear correlation coefficient is not lower than 0.9999, and the measurement range spans more than 7 orders of magnitude.

[0041] 7、The measuring device of the present application, when measuring the therapeutic level radiation dose, selects a gamma radiation dose detector composed of a semiconductor heterojunction device and cesium copper iodine (Cs3Cu2I5) scintillator, etc., compared with the traditional scintillator detector using a photomultiplier tube, does not need a high-voltage power supply, a voltage divider, etc., the structure is simplified, and the semiconductor heterojunction device is much lower in price than the photomultiplier tube, so the manufacturing cost of the measuring device is greatly reduced.

[0042] 8、The measuring device of the present application can dope cesium copper iodine (Cs3Cu2I5) to enhance the performance of the initial material, further improve the light yield, and improve the sensitivity, especially for the measurement of weak signals. Among them, the cesium copper iodine single crystal doped with Tl (thallium) (Cs3Cu2I5:Tl) shows obvious improvement in the light yield caused by radiation.

[0043] 9、The measuring device of the present application places the cesium copper iodine single crystal scintillator and the photoelectric conversion device in the shielding shell, which can reduce electromagnetic interference.

[0044] 10、The measuring device of the present application, the cesium copper iodine single crystal scintillator and the photoelectric conversion device are arranged in close contact, the transmission efficiency is high when in close contact, and the sensitivity is relatively high.

[0045] 11、The cesium copper iodine single crystal scintillator in the measuring device of the present application is a single crystal with a diameter of φ3-50mm and a thickness of 1-100mm, the measurement result is accurate, and the size range is easy to prepare and low in cost.

[0046] 12、The measuring method of the present application is simple to operate, fast and efficient in the measurement process, the measurement range spans 7 orders of magnitude, the measurement result is accurate and reliable, has excellent dose response linearity, and the linear correlation coefficient is greater than 0.9999. BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 1 It is a structural schematic view of the radiation dose measuring device based on the cesium copper iodine scintillator of the present application;

[0048] Figure 2 It is a working principle view of the radiation dose measuring device based on the cesium copper iodine scintillator of the present application;

[0049] Figure 3A structure schematic diagram of an embodiment of a radiation dose measuring device based on a cesium copper iodine scintillator according to the present application;

[0050] Figure 4 A dose response linear fitting curve diagram obtained by a radiation dose measuring method based on a cesium copper iodine scintillator according to the present application.

[0051] Reference signs are:

[0052] 1 - cesium copper iodine single crystal scintillator, 2 - photoelectric conversion device, 3 - measuring unit, 4 - shielding shell. DETAILED DESCRIPTION

[0053] The present application will be described in detail below with the aid of the accompanying drawings and embodiments.

[0054] The present application belongs to the category of scintillation detectors, and the measuring principle is to measure the dose through the average current of the total output of the scintillator light. The scintillator is divided into inorganic scintillator and organic scintillator. The inorganic scintillator includes NaI(Tl), CsI(Tl), CsI(Na), ZnS(Ag), LaBr3(Ce), etc. The organic scintillator is mostly aromatic hydrocarbons. The commonly used inorganic scintillators are NaI(Tl), CsI(Na), and LaBr3(Ce), which have the advantages of high luminous efficiency and normal temperature use, and the disadvantages of being easily deliquesced in air and needing to be sealed to prevent moisture. The organic scintillator has short light decay time, low light yield, and low atomic number atoms, which is suitable for measuring beta rays and neutrons, and has small interaction probability with gamma rays. The traditional scintillation detector system for gamma ray measurement is composed of a sodium iodide scintillator or a cesium iodide scintillator, a light guide, a photomultiplier tube, a high-voltage power supply, a voltage divider, and a measuring unit, etc., which is suitable for low dose rate measurement. When working, the photomultiplier tube works at a high voltage of 600V-1500V, and the series resistance voltage divider supplies power. The light conversion efficiency and gain are easily changed with the working bias voltage, which causes the response sensitivity of the detector to be unstable. The present application selects a high light yield cesium copper iodine single crystal scintillator combined with a semiconductor heterojunction device without external bias voltage, which can well avoid the problem of unstable response sensitivity caused by high working bias voltage, and reduce energy consumption.

[0055] Cs3Cu2I5 single crystal is a zero-dimensional (0D) perovskite scintillator, and its luminescence mechanism is self-trapped exciton emission. The Cs3Cu2I5 single crystal has many excellent luminescence characteristics, including the realization of blue light emission (the luminescence center is 440 nm), a large Stokes shift (about 120 nm), a high effective atomic number, a high luminescence yield (32000 photons / MeV), a small self-absorption, a long luminescence decay time (about 900 ns), and the like. The emission spectrum of the Cs3Cu2I5 single crystal is in the visible light range, and the spectral response matching with a photoelectric conversion device is good, which is beneficial to the improvement of the photoelectric conversion efficiency. Meanwhile, the Cs and I atoms contained in the Cs3Cu2I5 single crystal are high atomic number atoms, and the interaction probability with gamma rays is high. The density (4.51 g / cm 3 ) of the Cs3Cu2I5 single crystal is large, and the gamma ray stopping power is strong. The Cs3Cu2I5 single crystal is used as a scintillator for gamma radiation dose measurement, and the energy conversion efficiency is high, and the high detection efficiency of gamma rays can be realized. In addition, the Cs3Cu2I5 single crystal scintillator is a transparent solid-state material, and has the characteristics of not being easy to deliquesce, strong stability, and not being easy to be affected by the environment such as air pressure, temperature, and humidity. Therefore, the Cs3Cu2I5 single crystal is a preferred material for stable gamma radiation dose measurement.

[0056] The application provides a radiation dose measurement device based on a Cs3Cu2I5 scintillator, as shown in the figure, which comprises a Cs3Cu2I5 single crystal scintillator 1, a photoelectric conversion device 2 arranged on a light emission path of the Cs3Cu2I5 single crystal scintillator 1, and a measurement unit 3 connected with an electrical signal output end of the photoelectric conversion device 2 through a signal cable. Figure 1

[0057] The Cs3Cu2I5 single crystal scintillator 1 is a new type of perovskite scintillator material, and its luminescence mechanism is self-trapped exciton emission. The Cs3Cu2I5 single crystal scintillator 1 can realize blue light emission (the luminescence center is 440 nm) and a large Stokes shift (about 120 nm). Meanwhile, the Cs3Cu2I5 single crystal scintillator 1 has a high luminescence yield (about 32000 photons / MeV), and contains Cs and I atoms which are high atomic number atoms and have a high interaction probability with gamma rays. The density (4.51 g / cm 3 ) of the Cs3Cu2I5 single crystal scintillator 1 is large, and the gamma ray stopping power is strong, so that the high detection efficiency of gamma rays can be realized. The emission spectrum of the Cs3Cu2I5 single crystal scintillator 1 is in the visible light range, and the spectral response matching with the photoelectric conversion device is good, so that the high photoelectric conversion efficiency can be realized. The luminescence decay time of the Cs3Cu2I5 single crystal scintillator 1 is long, about 900 ns. As a new type of scintillator material, the Cs3Cu2I5 single crystal scintillator 1 can be combined with the photoelectric conversion device to form a measurement device, and can be well used for stable X or gamma radiation dose measurement. In the application, the gamma radiation dose measurement is mainly described. In addition, the Cs3Cu2I5 single crystal scintillator 1 is a transparent solid-state material, is not easy to absorb moisture, is not deliquescent, and has good air stability, so that the technical problem that the radiation dose measurement result is easy to be affected by the environment such as air pressure, temperature, and humidity in the prior art can be avoided. ​

[0058] The cesium copper iodine single crystal scintillator 1 in the present application can be a doped cesium copper iodine single crystal (Cs3Cu2I5:X) or an undoped cesium copper iodine single crystal (Cs3Cu2I5), which is selected according to the intensity of the object. The undoped cesium copper iodine single crystal (Cs3Cu2I5) can be used for the measurement of ordinary intensity gamma radiation, and the light yield of the undoped cesium copper iodine single crystal (Cs3Cu2I5) is about 32000 photons / MeV; the measurement of gamma radiation with smaller intensity can be performed by doping with a corresponding metal element to improve the light yield of the scintillator and thus improve the sensitivity of the scintillator measurement. For example, the light yield of the cesium copper iodine single crystal (Cs3Cu2I5:Tl) doped with Tl (thallium) can be as high as 90000 photons / MeV. The diameter of the cesium copper iodine single crystal scintillator is φ3-50mm, and the thickness is 1-100mm. If the size of the single crystal is too small, the measurement signal is weak, and the signal-to-noise ratio cannot meet the measurement requirements; if the size of the single crystal is too large, the preparation is difficult, and the cost is high. In the embodiment, the diameter of the cesium copper iodine single crystal scintillator is preferably φ25mm, and the thickness is 20mm.

[0059] The photoelectric conversion device 2 is arranged on the light-emitting light path of the cesium copper iodine single crystal scintillator 1, and is used for receiving the fluorescent signal of the cesium copper iodine single crystal scintillator 1, converting the light signal into an electric signal, and connecting with the measurement unit 3. The cesium copper iodine single crystal scintillator 1 and the photoelectric conversion device 2 can be arranged in contact or not in contact, and are preferably arranged in close contact, because the transmission efficiency is relatively high when they are in close contact. In other embodiments, in a strong gamma radiation field, the cesium copper iodine single crystal scintillator 1 and the photoelectric conversion device 2 can also be placed at a certain angle (20°-70°). When they are arranged at an angle, the sensitivity will be correspondingly reduced according to the size of the angle. The larger the angle, the more the sensitivity is reduced, because the larger the angle, the less the light signal received by the photoelectric conversion device from the scintillator, and the lower the photoelectric conversion efficiency.

[0060] The device of the present application can be used for the measurement of gamma radiation dose rate of different levels. When used, a suitable photoelectric conversion device 2 needs to be selected according to the level of the gamma radiation dose rate. For example, when the gamma radiation dose rate level is the environmental level or the protection level, the radiation dose rate is small, and the signal is weak, so the photoelectric conversion device 2 can be a photomultiplier tube; when the gamma radiation dose rate level is the treatment level and above, the radiation dose rate is large, and the signal is strong, so the photoelectric conversion device 2 can be a semiconductor heterojunction device or a phototube.

[0061] The embodiment of the device of the present application is mainly described in detail for the gamma radiation dose rate level of the treatment level, and the photoelectric conversion device 2 is a semiconductor heterojunction device. The size of the semiconductor heterojunction device is 3× 2The use of semiconductor heterojunction devices as photoelectric conversion devices has the following advantages: 1) Semiconductor heterojunction devices can achieve high-efficiency photoelectric conversion of visible light in the range of 300–600 nm, i.e., high quantum efficiency; 2) They can operate in self-powered mode without external bias voltage, achieving high-efficiency conversion of photoelectric signals, while also simplifying operation, reducing energy consumption, and improving electrical safety; 3) In self-powered mode, the charge collection efficiency (CCE) of semiconductor heterojunction devices is 85% of that in the 20V–100V mode, achieving high detection efficiency for gamma rays; 4) They can achieve… High signal-to-noise ratio: At 100V, the dark current of the semiconductor heterojunction device is 10–5000 nA, and at 0V, the dark current is no higher than 3 pA. High signal-to-noise ratio can be achieved when measuring gamma dose using zero bias. 5) When the semiconductor heterojunction device operates in self-powered mode, the dark current is in the pA range. Compared to a 100V bias, the dark current is reduced by 20–400 times, which can greatly extend the lower limit of the gamma dose measurement range. The theoretical detection limit is below 10.2 mGy / h, achieving a large dynamic response range. In the range of 10 mGy / h to 10 kGy / h, the signal current of the measuring device responds linearly to the dose rate. Figure 4 As shown, the linear correlation coefficient is not less than 0.9999, and the measurement range spans more than 7 orders of magnitude; 6) Semiconductor heterojunction devices are not sensitive to light, and no light-avoidance operation is required, which improves the convenience of operation.

[0062] The measurement unit 3 is used to record the electrical signal of the photoelectric conversion device 2, and can be a benchtop power supply, an electrometer, or an amplitude analyzer.

[0063] To reduce electromagnetic interference, in other embodiments, a shielding shell 4 is also provided. The shielding shell 4 is made of copper and has two signal cable through holes on its side. Figure 3 As shown, the cesium copper iodine single crystal scintillator 1 and the photoelectric conversion device 2 are placed inside the shielding shell 4, and the side wall of the shielding shell 4 is provided with a through hole for the signal cable of the photoelectric conversion device 2 to pass through.

[0064] The principle of the device of the present invention is as follows: Figure 2 As shown: A novel perovskite cesium copper iodide single crystal material is used as a scintillator and placed in a gamma radiation field. When gamma rays irradiate the cesium copper iodide single crystal scintillator 1, they interact with each other, resulting in the photoelectric effect / Compton effect / electron pair effect, producing secondary high-energy electrons. These secondary high-energy electrons collide with electrons in the cesium copper iodide scintillator, producing conduction band electrons. During de-excitation, conduction band electrons and valence band holes undergo radiative recombination, emitting a fluorescence signal. The photoelectric conversion device 2 receives the fluorescence signal and converts it into an electrical signal. The measurement unit 3 records the electrical signal in the photoelectric conversion device 2. The gamma radiation dose information is then obtained by back-calculating the measured electrical signal using the following formula.

[0065] y = a + bx

[0066] x is the dose rate, unit: Gy / h;

[0067] y is the current, unit: nA;

[0068] a and b are the intercept and slope of the dose response linear function, respectively.

[0069] The gamma radiation dose measuring device has the advantages of wide measuring range, spanning 7 orders of magnitude, linear dose response, good repeatability, and being unaffected by environmental factors such as temperature, humidity, and air pressure.

[0070] The application also provides a method for measuring gamma radiation dose using the above device, comprising the following steps:

[0071] S1) Obtain the intercept and slope of the dose response linear function of the measuring device

[0072] S1.1) Install the measuring device, place the cesium copper iodine single crystal scintillator 1 in a known dose rate gamma radiation field, turn on the gamma source, and irradiate the cesium copper iodine single crystal scintillator with gamma rays, and record the electrical signal through the measuring unit;

[0073] S1.2) After reaching the set time, turn off the gamma source;

[0074] S1.3) Use the known dose rate and corresponding electrical signal to fit the dose response linear function by the following formula to obtain the intercept a and slope b:

[0075] y = a + bx

[0076] x is the dose rate, unit: Gy / h;

[0077] y is the current, unit: nA;

[0078] a and b are the intercept and slope of the dose response linear function, respectively.

[0079] As Figure 4 shown, the intercept a and slope b in this embodiment are 0.048 and 2.45, respectively, and the linear correlation coefficient is 0.9999.

[0080] S2) Place the cesium copper iodine single crystal scintillator 1 in a gamma radiation field of the radiation dose to be measured, turn on the gamma source, and irradiate the cesium copper iodine single crystal scintillator with gamma rays, and record the electrical signal through the measuring unit;

[0081] S3) After reaching the set time, turn off the gamma source;

[0082] S4) Use the formula of step S1.3) and the intercept and slope to calculate the radiation dose rate to be measured from the electrical signal of step S2).

Claims

1. A method for measuring radiation dose based on cesium copper iodine scintillator, implemented based on a device for measuring radiation dose based on cesium copper iodine scintillator, the device comprising a cesium copper iodine single crystal scintillator (1), a photoelectric conversion device (2) arranged on a light path of the cesium copper iodine single crystal scintillator (1), and a measuring unit (3) connected to an electrical signal output end of the photoelectric conversion device (2) through a signal cable; the cesium copper iodine single crystal scintillator (1) is used to convert a radiation dose of gamma rays into a fluorescent signal; gamma rays irradiate the cesium copper iodine single crystal scintillator (1) to generate interaction and emit a fluorescent signal, the photoelectric conversion device (2) receives the fluorescent signal and converts the fluorescent signal into an electrical signal, and the measuring unit (3) records the electrical signal in the photoelectric conversion device (2); the photoelectric conversion device (2) is a semiconductor heterojunction device or a phototube, and the semiconductor heterojunction device operates in a self-powered mode with zero bias voltage; and the method comprises the following steps: S1) obtaining an intercept and a slope of a dose response linear function of the measuring device; S1.1) installing the measuring device, placing the cesium copper iodine single crystal scintillator (1) in a gamma radiation field with a known dose rate, turning on a gamma source, irradiating the cesium copper iodine single crystal scintillator (1) with gamma rays, and recording an electrical signal by the measuring unit (3); S1.2) turning off the gamma source after a set time; S1.3) obtaining the intercept a and the slope b by linear fitting of the known dose rate and the corresponding electrical signal according to the following formula: y=a+bx, wherein x is the dose rate, unit: Gy / h; y is the current, unit: nA; a and b are respectively the intercept and the slope of the dose response linear function; S2) placing the cesium copper iodine single crystal scintillator (1) in a gamma radiation field with a to-be-measured radiation dose rate, turning on the gamma source, irradiating the cesium copper iodine single crystal scintillator (1) with gamma rays, and recording an electrical signal by the measuring unit (3); S3) turning off the gamma source after a set time; and S4) calculating the to-be-measured radiation dose rate by the electrical signal obtained in step S2) according to the formula in step S1.3) and the intercept and the slope. 2.The method according to claim 1, characterized in that: the cesium copper iodine single crystal scintillator (1) is undoped cesium copper iodine single crystal Cs3Cu2I5 or doped cesium copper iodine single crystal Cs3Cu2I5:X, wherein X is a metal doping element. 3.The method according to claim 2, characterized in that: the doped cesium copper iodine single crystal scintillator is Tl-doped cesium copper iodine single crystal Cs3Cu2I5:Tl or Na-doped cesium copper iodine single crystal Cs3Cu2I5:Na. 4.The method according to claim 3, characterized in that: further comprising a shielding shell (4); and the shielding shell (4) is used to place the cesium copper iodine single crystal scintillator (1) and the photoelectric conversion device (2), and a through hole is arranged on a side wall of the shielding shell (4) for the signal cable to pass through. characterized in that ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 5. The method for measuring radiation dose based on cesium-copper-iodine scintillator according to claim 4, characterized in that: the cesium-copper-iodine single crystal scintillator (1) is in close contact with a photoelectric conversion device (2).

6. The method for measuring radiation dose based on cesium-copper-iodine scintillator according to claim 5, characterized in that: the measuring unit (3) is any one of a table power supply, an electrometer and an amplitude analyzer.

7. The method for measuring radiation dose based on cesium-copper-iodine scintillator according to claim 6, characterized in that: the diameter of the cesium-copper-iodine single crystal scintillator (1) is φ3-50mm, and the thickness is 1-100mm. The semiconductor heterojunction device has a size of 3 x 3 to 50 x 50 mm 2 .

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