Portable large-area alpha-beta detection system

Abstract

The embodiment of the invention discloses a portable large-area alpha and beta detection system. The system comprises a signal detection unit, wherein the signal detection unit comprises a large-area composite scintillator; the large-area composite scintillator is formed by compounding a plastic scintillator layer and a ZnS coating attached to the surface of the plastic scintillator layer, and the surface of the ZnS coating is covered with a light-proof film; a reflection cabin; the reflection bin is provided with an inner reflection wall in an elliptical paraboloid shape, the reflection bin is arranged above the large-area composite scintillator, and a closed light chamber is formed between the inner reflection wall of the reflection bin and a plastic scintillator layer of the large-area composite scintillator; a hemispherical lens; the hemispherical lens comprises a plane end and a spherical end; the hemispherical lens is arranged at the geometric center part of the reflection bin, and the spherical end extends into the reflection bin; and the photoelectric converter is arranged at the plane end of the hemispherical lens.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of radioactive detection, and particularly relates to a portable large-area alpha-beta detection system. BACKGROUND

[0002] At present, the detection of alpha-beta radioactivity has low resolution accuracy and poor stability, and the detection instrument is large and inconvenient to use. SUMMARY

[0003] Therefore, some embodiments disclose a portable large-area alpha-beta detection system, which comprises a signal detection unit, and the signal detection unit comprises:

[0004] a large-area composite scintillator; the large-area composite scintillator is composed of a plastic scintillator layer and a ZnS coating layer attached to the surface of the plastic scintillator layer, and the surface of the ZnS coating layer is covered with a light-proof film;

[0005] a reflection chamber; the reflection chamber has an inner reflection wall in the shape of an elliptic paraboloid, and the reflection chamber is arranged above the large-area composite scintillator to form a sealed light chamber between the inner reflection wall and the plastic scintillator layer of the large-area composite scintillator; the geometric center of the plastic scintillator layer is taken as the origin of the coordinate system, and the elliptic paraboloid shape of the inner reflection wall is represented as:

[0006]

[0007] wherein x and y are horizontal coordinates, and z is a vertical coordinate;

[0008] a hemispherical lens; the hemispherical lens comprises a planar end and a spherical end; the hemispherical lens is arranged at the geometric center of the reflection chamber, and the spherical end extends into the interior of the reflection chamber;

[0009] a photoelectric converter arranged at the planar end of the hemispherical lens.

[0010] Further, some embodiments disclose a portable large-area alpha-beta detection system, wherein the thickness of the plastic scintillator layer is between 0.5 and 1 mm, the surface roughness Ra is between 0.005 and 0.02 μm, and the reflectivity of light with a wavelength of 380-750 nm is 90-95%.

[0011] Some embodiments disclose a portable large-area alpha-beta detection system, wherein the area of the large-area composite scintillator is much larger than the projection area of the hemispherical lens.

[0012] Some embodiments disclose a portable large-area alpha-beta detection system, wherein the light-proof film is an aluminum-coated film with a thickness of 3-6 μm.

[0013] Some embodiments of the portable large-area αβ detection system also include a front-end processing circuit unit for processing the photoelectric signal output by the detection unit; the front-end processing circuit unit includes a first-stage in-phase proportional amplifier circuit module, a second-stage in-phase proportional amplifier circuit module, and a hysteresis comparison amplifier circuit module connected in sequence.

[0014] The first-stage inverting proportional amplifier circuit module includes:

[0015] First operational amplifier U1;

[0016] A resistor R19 is set between the inverting input terminal and the output terminal of the first operational amplifier U1; a connecting resistor R24 ​​is set at the inverting input terminal, and resistor R24 ​​is grounded.

[0017] The positive input terminal of the first operational amplifier U1 is connected to a resistor R8, which is connected to the input signal. Resistor R8 is further connected to resistor R6, which is connected to resistors R4 and R5. Resistor R4 is further grounded, and resistor R5 is further connected to the positive voltage terminal of the first operational amplifier U1.

[0018] The negative voltage terminal of the first operational amplifier U1 is grounded;

[0019] The second-stage non-inverting amplifier circuit module includes:

[0020] Second operational amplifier U2;

[0021] The non-inverting input terminal of the second operational amplifier U2 is connected to a resistor R12, and a capacitor C10 is connected to the resistor R12. The capacitor C10 is connected to the output terminal of the first non-inverting proportional amplifier circuit module. A resistor R15 is connected between the resistor R12 and the capacitor C10, and the resistor R15 is grounded.

[0022] A resistor R20 is set between the inverting input terminal and the output terminal of the second operational amplifier U2; a connecting resistor R23 is set at the inverting input terminal, and resistor R23 is grounded.

[0023] The positive voltage terminal of the second operational amplifier U2 is connected to the power supply VCC_A, and the negative voltage terminal is grounded.

[0024] The hysteresis comparator circuit module includes:

[0025] Third operational amplifier U3;

[0026] The inverting input of the third operational amplifier U3 is set with resistor R14, and resistor R14 is connected to DAC_TH1.

[0027] A connecting resistor R7 is provided between the positive input terminal and the output terminal of the third operational amplifier U3. A connecting resistor R13 is further provided between resistor R7 and the output terminal of the second inverting proportional amplifier circuit module.

[0028] The positive voltage terminal of the third operational amplifier U3 is connected to the power supply VCC_A, and the negative voltage terminal is grounded.

[0029] The sixth port of the third operational amplifier U3 is grounded.

[0030] Some embodiments of the portable large-area αβ detection system also include a main control circuit unit; the main control circuit unit is configured to process the pulse signal output by the front-end processing circuit unit; the pulse signal processing method distinguishes α particles and β particles by comparing the width of the level pulses.

[0031] Some embodiments of the portable large-area αβ detection system disclose a pulse signal processing method that specifically includes:

[0032] A pulse level signal was detected at the input terminal;

[0033] Determine if it is a high-level signal;

[0034] If not, continue to detect the input level signal;

[0035] If yes, the timer starts counting down and checks if the pulse width of the high-level pulse signal is greater than the time width threshold. If yes, it is determined to be an alpha particle, and the alpha channel accumulates; if no, it is determined to be a beta particle, and the beta channel accumulates.

[0036] By statistically analyzing the cumulative values ​​of the β and α channels every 1 second, the cps values ​​of α and β particles can be calculated.

[0037] The portable large-area αβ detection system disclosed in some embodiments also includes:

[0038] A housing is used to house the signal detection unit, the front-end processing circuit unit, and the main control circuit unit; a display screen is provided on the housing.

[0039] A handle is provided and connected to one end of the housing, and the interior of the handle has a chamber for housing the battery;

[0040] An alarm component, located inside the housing, is configured to issue an alarm signal when the number of alpha particles or beta particles exceeds a set alarm threshold.

[0041] The portable large-area αβ detection system disclosed in this invention achieves simultaneous detection of α and β rays on the surface of an object by employing a large-area composite scintillator; it achieves effective differentiation of α and β ray signals through a time-width discrimination method; and it enables detection of a large area by a single small-area photodetector through a specific light collection chamber, effectively reducing system cost and simplifying back-end circuitry and structure. The composite scintillator is solid-state and can operate without inflation, making it suitable for portable radiation detection. Attached Figure Description

[0042] Figure 1 , One Schematic diagram of the portable large-area αβ detection system disclosed in these embodiments;

[0043] Figure 2 , One Some embodiments disclose schematic diagrams of the signal detection unit structure;

[0044] Figure 3 , One Some embodiments disclose schematic diagrams of the shape of an elliptic paraboloid;

[0045] Figure 4 , One Some embodiments disclose schematic diagrams of the front-end processing circuit unit structure;

[0046] Figure 5 , One A schematic diagram of the comparison of α and β signals disclosed in some embodiments.

[0047] Figure Labels

[0048] Detailed Implementation

[0049] The term "embodiment" used herein, as an example, is not necessarily to be construed as superior to or better than other embodiments. Performance testing in these embodiments of the invention, unless otherwise specified, employs conventional testing methods in the art. It should be understood that the terminology used in these embodiments is merely for describing particular implementations and is not intended to limit the scope of the disclosure of these embodiments.

[0050] Unless otherwise stated, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the embodiments of this invention pertain; other experimental methods and technical means not specifically noted in the embodiments of this invention refer to experimental methods and technical means commonly used by one of ordinary skill in the art.

[0051] The terms “basic” and “approximately” as used herein are used to describe small fluctuations. For example, they can mean less than or equal to ±5%, such as less than or equal to ±2%, such as less than or equal to ±1%, such as less than or equal to ±0.5%, such as less than or equal to ±0.2%, such as less than or equal to ±0.1%, such as less than or equal to ±0.05%. Numerical data presented or expressed in range format herein are used for convenience and brevity only, and should therefore be interpreted flexibly to include not only the explicitly listed values ​​that define the range, but also all independent values ​​or subranges contained within that range. For example, a numerical range of “1–5%” should be interpreted to include not only the explicitly listed values ​​from 1% to 5%, but also the independent values ​​and subranges within the indicated range. Thus, this numerical range includes independent values ​​such as 2%, 3.5%, and 4%, and subranges such as 1%–3%, 2%–4%, and 3%–5%, etc. This principle also applies to ranges that list only one value. Furthermore, this interpretation applies regardless of the width of the range or the characteristics described.

[0052] In this document, including in the claims, conjunctions such as "comprising," "including," "with," "having," "containing," "involving," and "accommodating" are understood to be open-ended, meaning "including but not limited to." Only the conjunctions "consisting of" and "composed of" are closed conjunctions.

[0053] To better illustrate the content of this invention, numerous specific details are provided in the following detailed embodiments. Those skilled in the art should understand that the invention can be practiced even without certain specific details. In the embodiments, some methods, means, instruments, and devices well-known to those skilled in the art are not described in detail, in order to highlight the spirit of the invention.

[0054] Without conflict, the technical features disclosed in the embodiments of the present invention can be combined arbitrarily, and the resulting technical solution belongs to the content disclosed in the embodiments of the present invention.

[0055] The technical details are further illustrated below with reference to the embodiments and accompanying drawings.

[0056] In some implementations, such as Figure 1As shown, the portable large-area αβ detection system includes: a signal detection unit 1 for detecting α and β radiation signals, a front-end processing circuit unit 2 for processing the detected radiation signals, and a main control circuit unit 3; a housing 4 is positioned above the signal detection unit 1, the front-end processing circuit unit 2, and the main control circuit unit 3; the housing has an opening at the bottom, and the signal detection unit 1 is located at the opening at the bottom of the housing 4; a handle 5 is connected to one end of the housing 4, and the handle 5 has an internal cavity containing a battery 6; typically, the housing can be made of plastic or metal; if a plastic housing is used, the inside of the housing needs to be coated with conductive paint to prevent external electromagnetic interference; an indicator light 41 is located at the front of the top of the housing, a display screen 42 is located in the middle, and a button 43 is located at the rear; a vibration motor 7 is located inside the housing 4 near the handle; wherein, the indicator light... 41 is an alarm indicator light; when the number of alpha or beta particles detected exceeds the set alarm threshold, this indicator light will flash red. Display screen 42 displays measured values, historical data, and menu information. Front-end processing circuit unit 2 amplifies and compares the electrical signal output from the detection unit, then outputs a level pulse signal. Main control circuit unit 3 controls the vibration motor, indicator lights, buttons, and display screen, and performs time analysis and counting statistics on the level pulse signal output from the front-end processing circuit unit. Button 43 consists of a power switch, a menu button, and a display interface switching button, used to operate the content displayed on the screen. The handle can be used for one-handed grip. Battery 6 powers the entire system. Vibration motor 7 is a vibration alarm component; when the number of alpha or beta particles detected exceeds the set alarm threshold, the vibration motor will vibrate to trigger an alarm.

[0057] In some implementations, such as Figure 2 As shown, the signal detection unit includes:

[0058] Large-area composite scintillator 11; The large-area composite scintillator 11 is composed of a plastic scintillator layer 111 and a ZnS coating 112 attached to the surface of the plastic scintillator layer, and the surface of the ZnS coating 112 is covered with a light-shielding film 113.

[0059] In some embodiments, the thickness of the plastic scintillator layer is between 0.5 and 1 mm, the surface roughness Ra is between 0.005 and 0.02 μm, and the reflectivity to light with wavelengths of 380 to 750 nm is 90% to 95%.

[0060] In some embodiments, the light-shielding film is an aluminum-plated film with a thickness of 3~6μm;

[0061] Reflective chamber 12; The reflective chamber 12 has an inner reflective wall in the shape of an elliptical parabola. The reflective chamber 12 is disposed above the large-area composite scintillator 11, and a sealed light chamber is formed between the inner reflective wall of the reflective chamber 12 and the plastic scintillator layer 111 of the large-area composite scintillator 11.

[0062] Typically, the bottom edge of the reflective surface on the inner wall of a sealed light chamber is rounded, with the upper end of the rounded surface tangent to the main body of the reflective surface and the lower end perpendicular to the light-emitting surface, thus achieving the sealing of the light chamber.

[0063] With the geometric center of the plastic scintillator layer as the origin of the coordinate system, the elliptic parabolic shape of the inner reflecting wall is represented as:

[0064]

[0065] Where x and y are the horizontal coordinates, and z is the vertical coordinate;

[0066] Hemispherical lens 13; hemispherical lens 13 includes a planar end and a spherical end; hemispherical lens 13 is located at the geometric center of the reflection chamber 12, and the spherical end extends into the interior of the reflection chamber; typically, the area of ​​the large-area composite scintillator is much larger than the projected area of ​​the hemispherical lens.

[0067] The photoelectric converter 14 is located at the planar end of the hemispherical lens.

[0068] Typically, the photoelectric converter can be a photomultiplier tube (PMT) or a silicon photomultiplier tube (SiPM). One end of the hemispherical lens is flat, and the other end is spherical. The spherical end extends into the optical chamber, and the photoelectric converter is placed at the flat end. The photosensitive surface of the photoelectric converter is in close contact with the flat end of the lens and coupled with optical silicone grease. The sealed optical chamber is filled with air, and the inner wall of the optical chamber is an arc-shaped reflective surface used to collect as much light as possible emitted from the surface of the composite scintillator into the hemispherical lens. Generally, taking any point on the surface of the composite scintillator as a light source, after being collected by the lens, the uniformity of light collection from all points is greater than 50%. To achieve this goal, the shape of the inner wall of the optical chamber in this application is specifically designed. Simultaneously, the reflective surface uses an enhanced aluminum reflective coating, achieving a reflectivity ≥96% in the visible light band (380~750nm).

[0069] In some embodiments, the inner wall of the light chamber is shaped like an elliptic parabola, mathematically described as follows:

[0070]

[0071] The origin of the coordinate system is located at the geometric center of the composite scintillator surface, i.e., (0,0,0); the Z-axis is vertically upward, and the surface plane of the composite scintillator is located in the Z=0 plane; x and y are horizontal coordinates, with ranges of [-50,50] mm and [-85,85] mm, respectively.

[0072] In some embodiments, the shape of the elliptic parabola is as follows: Figure 3 As shown; the upper reflecting surface is an elliptic parabola, and the center of the hemispherical lens is located on the reflecting surface; the projection of the center of the lens onto the lower composite scintillator emitting plane coincides with the center of the composite scintillator emitting plane.

[0073] Typically, radiation particles incident on a composite scintillator deposit energy, causing ionization excitation of atoms (or ions, molecules) within the scintillator. The excited particles then de-excite, emitting scintillating photons with wavelengths close to visible light. The scintillator medium is transparent to its own emitted light and does not exhibit self-absorption. Specifically, the detection efficiency of a plastic scintillator layer for β-rays can reach 90%–99%, and with sufficient thickness, it also exhibits relatively high detection efficiency for γ-rays. To prevent γ-rays in the environment from depositing energy in the plastic scintillator and creating background counts, the thickness of the plastic scintillator is generally controlled between 0.5 and 1 mm to ensure that the β-ray background is below 15 cps. To prevent light loss from the optical chamber due to light loss on the inner surface of the plastic scintillator, the surface roughness Ra is required to be between 0.005 and 0.02 μm, with a reflectivity of 90%–95% (380–750 nm). The ZnS coating is applied to one side of the plastic scintillator by spraying. Since the range of alpha rays in ZnS is only a few micrometers, a ZnS coating with a thickness of a few tens of micrometers can achieve a detection efficiency of 95-99% for alpha rays. The light-shielding film is used to block visible light while minimizing the obstruction of alpha particles. Generally, an aluminum-plated film is used, and the thickness of a single layer is generally 3-6 μm.

[0074] In some embodiments, the front-end processing circuit unit includes a first-stage inverting proportional amplifier circuit module, a second-stage inverting proportional amplifier circuit module, and a hysteresis comparator amplifier circuit module connected in sequence.

[0075] like Figure 4 As shown, the first-stage non-inverting proportional amplifier circuit module includes: a first operational amplifier U1; a resistor R19 is provided between the inverting input terminal and the output terminal of the first operational amplifier U1; a resistor R24 ​​is provided connected to the inverting input terminal, and the resistor R24 ​​is grounded; a resistor R8 is connected to the non-inverting input terminal of the first operational amplifier, and the resistor R8 is connected to the input signal; a resistor R6 is further provided between the resistor R8 and the resistors R4 and R5, wherein the resistor R4 is further grounded, and the resistor R5 is further connected to the positive voltage terminal of the first operational amplifier U1; the negative voltage terminal of the first operational amplifier U1 is grounded; the voltage amplification factor formula of the first non-inverting proportional amplifier circuit module is:

[0076]

[0077] The second-stage non-inverting proportional amplifier circuit module includes: a second operational amplifier U2; a resistor R12 is connected to the non-inverting input terminal of the second operational amplifier U2, and a capacitor C10 is connected to the resistor R12, with the capacitor C10 connected to the output terminal of the first non-inverting proportional amplifier circuit module; a resistor R15 is connected between the resistor R12 and the capacitor C10, and the resistor R15 is grounded; a resistor R20 is connected between the inverting input terminal and the output terminal of the second operational amplifier U2; a resistor R23 is connected to the inverting input terminal, and the resistor R23 is grounded; the positive voltage terminal of the second operational amplifier U2 is connected to power supply VCC_A, and the negative voltage terminal is grounded; the voltage amplification factor formula of the second non-inverting proportional amplifier circuit module is:

[0078]

[0079] The hysteresis comparator circuit module includes: a third operational amplifier U3; a resistor R14 is set at the inverting input terminal of the third operational amplifier U3, and the resistor R14 is connected to DAC_TH1; a resistor R7 is set between the non-inverting input terminal and the output terminal of the third operational amplifier U3, and the resistor R7 is further connected to a resistor R13, which is connected to the output terminal of the second non-inverting proportional amplifier circuit module; the positive voltage terminal of the third operational amplifier U3 is connected to the power supply VCC_A, and the negative voltage terminal is grounded; the sixth port of the third operational amplifier U3 is grounded.

[0080] Typically, the front-end processing circuit unit is used to distinguish between alpha and beta signals based on signal width, while preserving complete timing information while eliminating noise. Specifically, the first-stage inverting proportional amplifier module performs primary amplification of the signal from the photoelectric converter input at the sin terminal, and the second-stage inverting proportional amplifier module adjusts the amplification factor to the appropriate level.

[0081] Typically, the core function of a non-inverting proportional amplifier is to amplify the input signal without inversion, fully preserving the pulse widths of the α and β signals. The input signal is connected to the non-inverting input of the op-amp, and the output signal is fed back to the inverting input through a resistor divider, satisfying the ideal op-amp characteristics of "virtual short" (V+ = V−) and "virtual open" (input current is 0).

[0082] In the first-stage non-inverting proportional amplifier circuit module, Sin is the signal input terminal. Resistors R4, R5, and R6 form a DC bias circuit, which can realize the signal level boosting, raising the negative voltage part to the range of 0~Vcc. U1 is the first-stage operational amplifier, resistor R19 is the feedback resistor, and R24 is the inverting input terminal grounding resistor.

[0083] A capacitor C10 is used for coupling between the first-stage forward proportional amplifier circuit and the second-stage forward proportional amplifier circuit to remove the DC bias of the first-stage amplifier circuit output; resistor R15 is a grounding resistor used to discharge the charge of capacitor C10. Resistor R12 is a current-limiting resistor at the signal input terminal of the second-stage forward proportional amplifier circuit module, resistor R20 is a feedback resistor of the second-stage amplifier circuit, and R25 is a grounding resistor for the inverting input of the second-stage amplifier circuit.

[0084] In the hysteresis comparator circuit module, the pulse signal output from the second-stage amplifier circuit enters the positive input terminal of the third operational amplifier U3 after passing through the current-limiting resistor R13. DAC_TH1 is the comparison threshold voltage, which is controlled by the MCU and connected to the negative input terminal of the third operational amplifier U3 after passing through the current-limiting resistor R14. When the positive pulse signal voltage is higher than the comparison threshold voltage, the third operational amplifier U3 outputs a high level TIM0. Due to the presence of the positive feedback resistor R7, when the pulse signal is lower than the comparator threshold voltage, the output state of U3 does not change; instead, when the pulse signal voltage is lower than the comparator threshold voltage by a certain value, U3 outputs a low level. Therefore, this hysteresis comparator circuit module has two threshold voltages: an upper threshold U+ and a lower threshold U-. When the input signal is higher than the upper threshold, the output jumps to a high level. When the input signal is lower than the lower threshold, the output jumps to a low level. This dual-threshold design can avoid the output voltage generating multiple level pulse signals when the input signal has slight jitter near the threshold value, thereby improving the anti-interference capability.

[0085] Some embodiments of the portable large-area αβ detection system also include a main control circuit unit; the main control circuit unit is configured to process pulse signals output by a front-end processing circuit unit; the pulse signal processing method distinguishes α particles and β particles by comparing the widths of the level pulses; such as Figure 5 As shown, the time widths of the β and α signals differ. Under the same threshold, the pulse width of the α signal output by the comparator is greater than that of the β signal. Therefore, α particles and β particles can be well distinguished by measuring the pulse width.

[0086] Some embodiments of the portable large-area αβ detection system disclose a pulse signal processing method that specifically includes:

[0087] A pulse level signal was detected at the input terminal;

[0088] Determine if it is a high-level signal;

[0089] If not, continue to detect the input level signal;

[0090] If yes, the timer starts counting down and checks if the pulse width of the high-level pulse signal is greater than the time width threshold. If yes, it is determined to be an alpha particle, and the alpha channel accumulates; if no, it is determined to be a beta particle, and the beta channel accumulates.

[0091] By statistically analyzing the cumulative values ​​of the β and α channels every 1 second, the cps values ​​of α and β particles can be calculated.

[0092] The portable large-area αβ detection system disclosed in this invention achieves simultaneous detection of α and β rays on the surface of an object by employing a large-area composite scintillator; it achieves effective differentiation of α and β ray signals through a time-width discrimination method; and it enables detection of a large area by a single small-area photodetector through a specific light collection chamber, effectively reducing system cost and simplifying back-end circuitry and structure. The composite scintillator is solid-state and can operate without inflation, making it suitable for portable radiation detection.

[0093] The technical solutions and technical details disclosed in the embodiments of this invention are merely illustrative of the inventive concept of this invention and do not constitute a limitation on the technical solutions of the embodiments of this invention. Any conventional changes, substitutions, or combinations made to the technical details disclosed in the embodiments of this invention have the same inventive concept as this invention and are within the protection scope of the claims of this invention.

Claims

1. A portable large-area αβ detection system, characterized in that, Includes a signal detection unit, the signal detection unit comprising: A large-area composite scintillator; the large-area composite scintillator is composed of a plastic scintillator layer and a ZnS coating attached to the surface of the plastic scintillator layer, and the surface of the ZnS coating is covered with a light-shielding film; A reflective chamber; the reflective chamber has an inner reflective wall in the shape of an elliptic paraboloid, the reflective chamber is disposed above the large-area composite scintillator, and a sealed optical chamber is formed between the inner reflective wall of the reflective chamber and the plastic scintillator layer of the large-area composite scintillator; with the geometric center of the plastic scintillator layer as the origin of the coordinate system, the elliptic paraboloid shape of the inner reflective wall is represented as: Where x and y are the horizontal coordinates, and z is the vertical coordinate; A hemispherical lens; the hemispherical lens includes a planar end and a spherical end; the hemispherical lens is disposed at the geometric center of the reflective chamber, and the spherical end extends into the interior of the reflective chamber; A photoelectric converter is disposed at the planar end of the hemispherical lens.

2. The portable large-area αβ detection system according to claim 1, characterized in that, The thickness of the plastic scintillator layer is between 0.5 and 1 mm, the surface roughness Ra is between 0.005 and 0.02 μm, and the reflectivity of light with wavelengths of 380 to 750 nm is 90 to 95%.

3. The portable large-area αβ detection system according to claim 1, characterized in that, The area of ​​the large-area composite scintillator is much larger than the projected area of ​​the hemispherical lens.

4. The portable large-area αβ detection system according to claim 1, characterized in that, The light-shielding film is an aluminum-plated film with a thickness of 3~6μm.

5. The portable large-area αβ detection system according to claim 1, characterized in that... It also includes a front-end processing circuit unit for processing the photoelectric signal output by the detection unit; the front-end processing circuit unit includes a first-stage in-phase proportional amplifier circuit module, a second-stage in-phase proportional amplifier circuit module, and a hysteresis comparison amplifier circuit module connected in sequence. The first-stage inverting proportional amplifier circuit module includes: First operational amplifier U1; A resistor R19 is set between the inverting input terminal and the output terminal of the first operational amplifier U1; a connecting resistor R24 ​​is set at the inverting input terminal, and resistor R24 ​​is grounded. The positive input terminal of the first operational amplifier U1 is connected to a resistor R8, which is connected to the input signal. Resistor R8 is further connected to resistor R6, which is connected to resistors R4 and R5. Resistor R4 is further grounded, and resistor R5 is further connected to the positive voltage terminal of the first U1. The negative voltage terminal of the first operational amplifier U1 is grounded; The second-stage inverting amplifier circuit module includes: Second operational amplifier U2; The non-inverting input terminal of the second operational amplifier U2 is connected to a resistor R12, and a capacitor C10 is connected to the resistor R12. The capacitor C10 is connected to the output terminal of the first non-inverting proportional amplifier circuit module. A resistor R15 is connected between the resistor R12 and the capacitor C10, and the resistor R15 is grounded. A resistor R20 is set between the inverting input terminal and the output terminal of the second operational amplifier U2; a connecting resistor R23 is set at the inverting input terminal, and resistor R23 is grounded. The positive voltage terminal of the second operational amplifier U2 is connected to the power supply VCC_A, and the negative voltage terminal is grounded. The hysteresis comparator circuit module includes: Third operational amplifier U3; The inverting input of the third operational amplifier U3 is set with resistor R14, and resistor R14 is connected to DAC_TH1. A connecting resistor R7 is provided between the positive input terminal and the output terminal of the third operational amplifier U3. A connecting resistor R13 is further provided between resistor R7 and the output terminal of the second inverting proportional amplifier circuit module. The positive voltage terminal of the third operational amplifier U3 is connected to the power supply VCC_A, and the negative voltage terminal is grounded. The sixth port of the third operational amplifier U3 is grounded.

6. The portable large-area αβ detection system according to claim 5, characterized in that... It also includes a main control circuit unit; the main control circuit unit is configured to process the pulse signal output by the front-end processing circuit unit; the pulse signal processing method distinguishes between α particles and β particles by comparing the width of the level pulses.

7. The portable large-area αβ detection system according to claim 6, wherein the pulse signal processing method specifically includes: A pulse level signal was detected at the input terminal; Determine if it is a high-level signal; If not, continue to detect the input level signal; If yes, the timer starts counting down and checks if the pulse width of the high-level pulse signal is greater than the time width threshold. If yes, it is determined to be an alpha particle, and the alpha channel accumulates; if no, it is determined to be a beta particle, and the beta channel accumulates. By statistically analyzing the cumulative values ​​of the β and α channels every 1 second, the cps values ​​of α and β particles can be calculated.

8. The portable large-area αβ detection system according to claim 7, characterized in that, Also includes: A housing is used to house the signal detection unit, the front-end processing circuit unit, and the main control circuit unit; a display screen is provided on the housing. A handle is provided and connected to one end of the housing, and the interior of the handle has a chamber for housing the battery; An alarm component, located inside the housing, is configured to issue an alarm signal when the number of alpha particles or beta particles exceeds a set alarm threshold.

Images