Nuclear radiation detection equipment and signal conditioning circuit thereof

Abstract

The invention relates to nuclear radiation detection equipment and a signal conditioning circuit thereof, and the circuit comprises a pre-amplification unit which is used for amplifying and isolating a detection signal and outputting a first amplified signal; the filtering forming unit is connected with the pre-amplification unit and is used for conditioning the first amplified signal into a narrow pulse signal; the main amplifying unit is connected with the filtering and forming unit and is used for conditioning the narrow pulse signal into a second amplified signal; and the discrimination unit is connected with the main amplification unit and is used for discriminating the pulses to be counted and the noise of the second amplified signal and outputting a counting signal representing the number of the pulses to be counted and the number of the noise of the second amplified signal. According to the invention, accumulation of pulse signals at a high counting rate can be eliminated, the energy spectrum resolution is improved, and interference caused by tiny vibration is eliminated.

Description

Technical Field

[0001] This invention relates to the field of nuclear radiation detection technology, and in particular to a nuclear radiation detection device and its signal conditioning circuit. Background Technology

[0002] Nuclear power plants release various types of particles or radiation (such as alpha rays, beta rays, gamma rays, and X-rays) during operation. Long-term or high-dose exposure to this radiation can lead to serious consequences such as cell damage, genetic mutations, and organ dysfunction, even endangering life. Therefore, developing technologies and equipment capable of real-time and accurate radiation dose detection is of great significance for protecting public health and the safety of the radiation environment.

[0003] Currently, commonly used nuclear radiation detection instruments typically convert physical signals into electrical signals using sensors, then count the number of pulses in the electrical signal to calculate the radiation dose. However, traditional signal processing methods often suffer from limitations such as limited gain, insufficient noise suppression, and small dynamic range. This leads to pulse signal accumulation at high count rates and false counts caused by minute vibrations, making it difficult to achieve high-precision and high-reliability radiation dose monitoring in complex environments, which is detrimental to nuclear power plant safety. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a nuclear radiation detection device and its signal conditioning circuit.

[0005] The technical solution adopted by this invention to solve its technical problem is: to construct a signal conditioning circuit for use in nuclear radiation detection equipment, wherein the nuclear radiation detection equipment includes a detector for detecting nuclear radiation particles and outputting a detection signal, and the signal conditioning circuit includes: A preamplifier unit is used to amplify and isolate the detection signal and output a first amplified signal; A filtering shaping unit, connected to the preamplifier unit, is used to condition the first amplified signal into a narrow pulse signal. The main amplification unit, connected to the filter shaping unit, is used to condition the narrow pulse signal into a second amplified signal. The discrimination unit, connected to the main amplification unit, is used to discriminate the pulses to be counted and noise in the second amplified signal, and output a counting signal representing the number of pulses to be counted and the number of noise in the second amplified signal.

[0006] Preferably, the preamplifier unit includes: A preamplifier is used to amplify the detection signal and output a first amplified signal; A voltage follower, connected to the preamplifier, is used to isolate the first amplified signal.

[0007] Preferably, the preamplifier includes a first operational amplifier U1, a first capacitor C1, a second capacitor C2, a third capacitor C3, a first resistor R1, and a second resistor R2; The inverting input of the first operational amplifier U1 is connected to the detection signal via the first capacitor C1. The inverting input of the first operational amplifier U1 is connected to the output of the first operational amplifier U1 via the second capacitor C2. The non-inverting input of the first operational amplifier U1 is connected to a first DC voltage via the second resistor R2. The non-inverting input of the first operational amplifier U1 is also grounded via the third capacitor C3. The output of the first operational amplifier U1 outputs the first amplified signal. The first operational amplifier U1, the first capacitor C1, the second capacitor C2, and the second resistor R2 constitute a first amplification circuit. The first amplification circuit provides a bias voltage to the detection signal through the first DC voltage and amplifies the AC component in the detection signal. The first resistor R1 is connected in parallel with the second capacitor C2 so that the first amplifier circuit can establish a stable operating point.

[0008] Preferably, the filter shaping unit includes a third operational amplifier U3, a fourth resistor R4, a fifth resistor R5, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a fifth capacitor C5, a sixth capacitor C6, a seventh capacitor C7, an eighth capacitor C8, a ninth capacitor C9, and a tenth capacitor C10. The inverting input of the third operational amplifier U3 is connected to the first terminal of the fourth resistor R4 via the sixth capacitor C6 and the fifth resistor R5. The second terminal of the fourth resistor R4 is connected to the preamplifier unit. The inverting input of the third operational amplifier U3 is also connected to the first terminal of the fourth resistor R4 via the fifth capacitor C5. The inverting input of the third operational amplifier U3 is also connected to the output terminal of the third operational amplifier U3 via the seventh resistor R7. The seventh capacitor C7 is connected in parallel with the seventh resistor R7. The non-inverting input of the third operational amplifier U3 is connected to the first DC voltage via the eighth resistor R8 and grounded via the eighth capacitor C8. The output terminal of the third operational amplifier U3 is connected to the first terminal of the tenth resistor R10 via the ninth resistor R9 and the tenth capacitor C10. The node formed by the connection of the ninth resistor R9 and the tenth capacitor C10 is grounded via the ninth capacitor C9. The second terminal of the tenth resistor R10 is connected to the main amplifier unit.

[0009] Preferably, the main amplification unit includes a fourth operational amplifier U4, an eleventh resistor R11, and a twelfth resistor R12; The inverting input of the fourth operational amplifier U4 is connected to the filtering and shaping unit. The inverting input of the fourth operational amplifier U4 is connected to the output of the fourth operational amplifier U4 via the eleventh resistor R11. The eleventh capacitor C11 is connected in parallel with the eleventh resistor R11. The non-inverting input of the fourth operational amplifier U4 is connected to the first DC voltage via the twelfth resistor R12. The fourth operational amplifier U4, the eleventh resistor R11, and the twelfth resistor R12 constitute a second amplification circuit for amplifying the amplitude of the narrow pulse signal. The second amplification circuit outputs the second amplified signal through the output of the fourth operational amplifier U4.

[0010] Preferably, the main amplification unit further includes a twelfth capacitor C12 and a thirteenth resistor R13; The twelfth capacitor C12 is connected in parallel with the eleventh resistor R11 to suppress high-frequency noise and prevent high-frequency oscillation. The thirteenth resistor R13 is connected between the output of the fourth operational amplifier U4 and the discrimination unit to increase the output impedance of the second amplified signal.

[0011] Preferably, the screening unit includes: The pulse to be counted discrimination unit is connected to the main amplification unit and is used to discern the pulses to be counted in the second amplified signal and output a first counting signal for determining the number of the pulses to be counted. The noise discrimination unit, connected to the main amplification unit, is used to discriminate noise in the second amplified signal and output a second counting signal to determine the amount of noise in the second amplified signal.

[0012] Preferably, the pulse discrimination unit includes a first comparator U5, a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16, a seventeenth resistor R17, and a thirteenth capacitor C13; The inverting input of the first comparator U5 is connected to the main amplification unit to receive the second amplified signal. The non-inverting input of the first comparator U5 is connected to the ground via the sixteenth resistor R16 and to the second DC voltage via the fifteenth resistor R15 and the fourteenth resistor R14. The output of the first comparator U5 is connected to the first terminal of the seventeenth resistor R17. The fourteenth resistor R14, the fifteenth resistor R15, and the sixteenth resistor R16 constitute a voltage divider circuit that divides the second DC voltage into a first voltage divider signal. The first comparator U5 compares the second amplified signal with the first voltage divider signal and outputs the first counting signal through the second terminal of the seventeenth resistor R17. The thirteenth capacitor C13 is connected in parallel with the sixteenth resistor R16 to suppress high-frequency noise.

[0013] Preferably, the noise discrimination unit includes a second comparator U6, an eighteenth resistor R18, a nineteenth resistor R19, a twentieth resistor R20, a twenty-first resistor R21, and a fourteenth capacitor C14; The non-inverting input of the second comparator U6 is connected to the main amplification unit to receive the second amplified signal. The inverting input of the second comparator U6 is connected to the second DC voltage via the nineteenth resistor R19 and the twentieth resistor R20, and via the eighteenth resistor R18. The output of the second comparator U6 is connected to the first terminal of the eleventh resistor R21. The eighteenth resistor R18, the nineteenth resistor R19, and the twentieth resistor R20 constitute a voltage divider circuit that divides the second DC voltage into a second voltage divider signal. The second comparator U6 compares the second amplified signal with the second voltage divider signal and outputs the second counting signal through the second terminal of the eleventh resistor R21. The fourteenth capacitor C14 is connected between the inverting input of the second comparator U6 and ground to suppress high-frequency noise.

[0014] In addition, the present invention also constructs a nuclear radiation detection device, including the signal conditioning circuit described above.

[0015] The technical solution of this invention filters and conditions the detection signal to output a counting signal that can accurately determine the number of nuclear radiation particles. It also eliminates the accumulation of pulse signals at high count rates, improves the energy spectrum resolution, and eliminates interference caused by minute vibrations, thus playing a positive role in improving the measurement accuracy of nuclear radiation detection equipment. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings: Figure 1 This is a circuit structure block diagram of the signal conditioning circuit in some embodiments of the present invention; Figure 2 This is a circuit schematic diagram of the preamplifier unit, the filter shaping unit, and the main amplifier unit in some embodiments of the present invention; Figure 3 This is a circuit schematic diagram of the pulse discrimination unit to be counted in some embodiments of the present invention; Figure 4 This is a circuit diagram of the noise discrimination unit in some embodiments of the present invention. Detailed Implementation

[0017] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0018] It should be noted that the flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily need to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0019] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0020] Figure 1 This is a circuit block diagram of a signal conditioning circuit in some embodiments of the present invention. This signal conditioning circuit is applied to existing nuclear radiation detection equipment, which may include a detector and a counter. The detector detects nuclear radiation particles and outputs a detection signal characterizing the number of nuclear radiation particles, while the counter calculates the number of nuclear radiation particles based on the count signal. By filtering and conditioning the detection signal, this signal conditioning circuit not only accurately determines the number of nuclear radiation particles through a count signal, but also eliminates the accumulation of pulse signals at high count rates, improves energy spectrum resolution, and eliminates interference caused by minute vibrations, thus playing a positive role in improving the measurement accuracy of nuclear radiation detection equipment.

[0021] like Figure 1 As shown, the signal conditioning circuit may include a preamplifier unit 1, a filter shaping unit 2, a main amplifier unit 3, and a discrimination unit 4.

[0022] The preamplifier unit 1 is connected to the detector to receive the detection signal output by the detector. The preamplifier unit 1 is used to amplify and isolate the detection signal and output the first amplified signal. It should be noted that the function of the preamplifier unit 1 is to initially amplify the characteristic signals (including effective signals and noise) of the detection signal so that the subsequent circuits can process and distinguish them, while isolating the amplified signal can prevent inter-stage crosstalk.

[0023] In some embodiments, such as Figure 2 As shown, the preamplifier unit 1 may include a preamplifier and a voltage follower.

[0024] The preamplifier is connected to the detector to receive the detection signal output by the detector. The preamplifier is used to amplify the detection signal and output the first amplified signal.

[0025] Furthermore, such as Figure 2 As shown, the preamplifier may include a first operational amplifier U1, a first capacitor C1, a second capacitor C2, a third capacitor C3, a first resistor R1, and a second resistor R2.

[0026] The inverting input of the first operational amplifier U1 is connected to the detection signal (S1) via the first capacitor C1. The inverting input of the first operational amplifier U1 is connected to its output via the second capacitor C2. The non-inverting input of the first operational amplifier U1 is connected to the first DC voltage (VBias) via the second resistor R2. The non-inverting input of the first operational amplifier U1 is also grounded via the third capacitor C3. The output of the first operational amplifier U1 outputs the first amplified signal. The first operational amplifier U1, the first capacitor C1, the second capacitor C2, and the second resistor R2 constitute the first amplification circuit. The first amplification circuit provides a bias voltage to the detection signal through the first DC voltage and amplifies the AC component in the detection signal. The first resistor R1 and the second capacitor C2 are connected in parallel to establish a stable operating point for the first amplification circuit.

[0027] Since the effective signal in the detection signal is an AC signal, this embodiment uses a first capacitor C1 and a second capacitor C2 to form a feedback loop. The gain coefficient of the first amplifier circuit can be adjusted by changing the values ​​of the first capacitor C1 and the second capacitor C2. Using a first DC voltage to provide the bias voltage avoids distortion of negative voltage or low voltage characteristic signals in the AC signal. The first resistor R1 provides a DC feedback bypass, preventing saturation amplification caused by the input bias current and offset voltage of the first operational amplifier U1, thus establishing a stable operating point. The second resistor R2 is preferably a high-value resistor, which increases the input impedance of the non-inverting input of the first operational amplifier U1, making the voltage at the non-inverting input of the first operational amplifier U1 as close as possible to the first DC voltage, thus improving the overall circuit stability. The third capacitor C3 is used to filter the voltage signal input to the non-inverting input of the first operational amplifier U1, further improving circuit stability.

[0028] The voltage follower is connected to the preamplifier and is used to isolate the first amplified signal.

[0029] Furthermore, such as Figure 2As shown, the voltage follower may include a second operational amplifier U2, a third resistor R3, and a fourth capacitor C4. One non-inverting input of the second operational amplifier U2 is connected to the output of the first operational amplifier U1 via the third resistor R3; the other non-inverting input of the second operational amplifier U2 is grounded via the fourth capacitor C4. The inverting input of the second operational amplifier U2 is connected to its output. The output of the second operational amplifier U2 is connected to the filter shaping unit 2 to input the isolated, amplified first signal to the filter shaping unit 2.

[0030] In this embodiment, the voltage follower serves as a signal buffer and isolates the preamplifier from the filter shaping unit 2. This not only prevents inter-stage crosstalk but also improves the load capacity of the first amplified signal and suppresses signal distortion caused by current shunting in subsequent stages. Furthermore, the third resistor R3 increases the input impedance (its function is similar to that of the second resistor R2). The fourth capacitor C4 acts as a filter.

[0031] The filtering and shaping unit 2 is connected to the preamplifier unit. The filtering and shaping unit 2 is used to condition the first amplified signal into a narrow pulse signal. The function of the filtering and shaping unit 2 is to perform pole-zero cancellation processing and filtering and shaping processing on the first amplified signal to obtain the narrow pulse signal. Pole-zero cancellation processing can adjust the signal undershoot, making the signal monotonically return to the baseline, thereby improving the effects of count rate overload and pulse amplitude superposition, and improving resolution and high count rate. After performing pole-zero cancellation processing, the filtering and shaping unit 2 further filters and shapes the signal to improve the signal-to-noise ratio, eliminate ballistic defects, and reduce pulse accumulation.

[0032] In some embodiments, such as Figure 2 As shown, the filter shaping unit 2 may include a third operational amplifier U3, a fourth resistor R4, a fifth resistor R5, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a fifth capacitor C5, a sixth capacitor C6, a seventh capacitor C7, an eighth capacitor C8, a ninth capacitor C9, and a tenth capacitor C10.

[0033] The inverting input of the third operational amplifier U3 is connected to the first terminal of the fourth resistor R4 via the sixth capacitor C6 and the fifth resistor R5. The second terminal of the fourth resistor R4 is connected to the preamplifier unit 1. The inverting input of the third operational amplifier U3 is also connected to the first terminal of the fourth resistor R4 via the fifth capacitor C5. The inverting input of the third operational amplifier U3 is also connected to the output of the third operational amplifier U3 via the seventh resistor R7. The seventh capacitor C7 and the seventh resistor R7 are connected in parallel. One of the non-inverting inputs of the third operational amplifier U3 is connected to the first DC voltage via the eighth resistor R8. The other non-inverting input is grounded via the eighth capacitor C8. The output of the third operational amplifier U3 is connected to the first terminal of the tenth resistor R10 via the ninth resistor R9 and the tenth capacitor C10. The node formed by the connection of the ninth resistor R9 and the tenth capacitor C10 is grounded via the ninth capacitor C9. The first terminal of the tenth resistor R10 is connected to the main amplifier unit 3.

[0034] In this embodiment, the third operational amplifier U3, the fifth capacitor C5, the sixth capacitor C6, the seventh capacitor C7, the eighth capacitor C8, the seventh resistor R7, the eighth resistor R8, the fourth resistor R4, and the fifth resistor R5 constitute a pole-zero cancellation circuit. The fifth capacitor C5, the sixth capacitor C6, the fourth resistor R4, and the fifth resistor R5 can generate a cancellation signal that cancels out the tail of the first amplified signal, thereby eliminating undershoot. The third operational amplifier U3, the seventh resistor R7, the eighth resistor R8, the seventh capacitor C7, and the eighth capacitor C8 constitute an inverting amplifier circuit. The amplification characteristics of the inverting amplifier circuit can enhance the effect of the cancellation signal, enabling rapid baseline recovery and effectively improving the effects of count rate overload and pulse amplitude superposition. The third operational amplifier U3, the seventh capacitor C7, the eighth capacitor C8, the ninth capacitor C9, the tenth capacitor C10, the seventh resistor R7, the eighth resistor R8, the ninth resistor R9, and the tenth resistor R10 constitute a filter shaping circuit. The ninth capacitor C9 and the ninth resistor R9 form a first-stage RC integrator network, and the tenth capacitor C10 and the tenth resistor R10 form an RC differentiator network. Together with the inverting amplifier circuit formed by the third operational amplifier U3, they complete the primary shaping, shaping the signal into an approximately symmetrical bell shape (Gaussian shape) in the time domain and forming a bandpass filter in the frequency domain to suppress high and low frequency noise. Understandably, the pole-zero cancellation circuit and the filter shaping circuit share the inverting amplifier circuit formed by the third operational amplifier U3, forming a unified structure with the advantage of simple circuit structure.

[0035] The main amplification unit 3 is connected to the filter shaping unit 2. The main amplification unit 3 is used to condition the narrow pulse signal into a second amplified signal.

[0036] In some embodiments, such as Figure 2As shown, the main amplification unit 3 may include a fourth operational amplifier U4, an eleventh capacitor C11, an eleventh resistor R11, and a twelfth resistor R12. The inverting input of the fourth operational amplifier U4 is connected to the second terminal of the tenth resistor R10 in the filter shaping unit 2. The inverting input of the fourth operational amplifier U4 is connected to the output of the fourth operational amplifier U4 via the eleventh resistor R11. The eleventh capacitor C11 is connected in parallel with the eleventh resistor R11. The non-inverting input of the fourth operational amplifier U4 is connected to a first DC voltage via the twelfth resistor R12. The fourth operational amplifier U4, the eleventh resistor R11, and the twelfth resistor R12 constitute a second amplification circuit for amplifying the amplitude of a narrow pulse signal. The second amplification circuit outputs a second amplified signal through the output of the fourth operational amplifier U4.

[0037] After the detection signal is processed by the preamplifier unit 1 and the filter shaping unit 2, most of the noise has been filtered out. Therefore, in this embodiment, the main amplification unit 3 can further amplify the amplitude of the narrow pulse signal so that the subsequent circuits can compare and distinguish it. Furthermore, the feedback network formed by the eleventh capacitor C11 and the eleventh resistor R11 not only stabilizes the pulse amplitude and controls the pulse width, but also shapes the signal into an approximately symmetrical bell shape (Gaussian shape) in the time domain, forming a bandpass filter in the frequency domain to suppress high and low frequency noise. The twelfth resistor R12 has a similar function to the second resistor R2. It forms a bandpass filter in the frequency domain to suppress high and low frequency noise, stabilize the pulse amplitude, and control the pulse width.

[0038] In some embodiments, such as Figure 2 As shown, the main amplification unit 3 may also include a twelfth capacitor C12 and a thirteenth resistor R13. The twelfth capacitor C12 is connected between the non-inverting input of the fourth operational amplifier U4 and ground to suppress high-frequency noise. The thirteenth resistor R13 is connected between the output of the fourth operational amplifier U4 and the discrimination unit 4 to increase the output impedance of the second amplified signal. Furthermore, after processing by the main amplification unit 3, the second amplified signal exhibits a Gaussian-like waveform, which improves the signal-to-noise ratio and aids in the subsequent circuitry's output discrimination.

[0039] The discrimination unit 4 is connected to the main amplification unit 3. The discrimination unit 4 is used to distinguish between the pulses to be counted and noise in the second amplified signal, and outputs a counting signal representing the number of pulses to be counted and the number of noise in the second amplified signal. The counting signal includes a first counting signal and a second counting signal.

[0040] In some embodiments, the discrimination unit 4 may include Figure 3 The pulse discrimination unit to be counted shown and Figure 4 The noise discrimination unit shown.

[0041] The pulse discrimination unit is connected to the main amplification unit 3. The pulse discrimination unit is used to discriminate the pulses to be counted in the second amplified signal and output a first counting signal to determine the number of pulses to be counted.

[0042] Furthermore, such as Figure 3 As shown, the pulse discrimination unit includes a first comparator U5, a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16, a seventeenth resistor R17, and a thirteenth capacitor C13. The inverting input of the first comparator U5 is connected to the main amplifier unit 3 to receive the second amplified signal (i.e., SIG). One path of the non-inverting input of the first comparator U5 is grounded through the sixteenth resistor R16, and the other path is connected to a second DC voltage (i.e., REF_2V5) through the fifteenth and fourteenth resistors R15 and R14. The output of the first comparator U5 is connected to the first terminal of the seventeenth resistor R17. The fourteenth, fifteenth, and sixteenth resistors R14, R15, and R16 form a voltage divider circuit that divides the second DC voltage into a first voltage divider signal. The first comparator U5 compares the second amplified signal with the first voltage divider signal and outputs the first counting signal through the second terminal of the seventeenth resistor R17. The thirteenth capacitor C13 is connected in parallel with the sixteenth resistor R16 to suppress high-frequency noise.

[0043] In this embodiment, the second amplified signal can be considered as a signal composed of multiple pulses to be counted. When a pulse to be counted arrives, the voltage of the second amplified signal is greater than the first voltage divider signal. At this time, the output of the first comparator U5 outputs a low level until the pulse to be counted has completely passed. Then, the voltage of the second amplified signal is less than the first voltage divider signal, and the first comparator U5 switches to output a high level. The pulse to be counted can be a valid pulse that represents the number of nuclear radiation particles (one valid pulse represents one nuclear radiation particle) or noise. Understandably, since both valid pulses and noise can make the second amplified signal exhibit a high level for a certain period of time, the number of pulses to be counted can be calculated based on the above principle. That is, when the counter in the nuclear radiation detection device detects that the first comparator U5 outputs a low-level signal for a certain period of time, the total number of pulses to be counted can be incremented by one.

[0044] In some embodiments, such as Figure 3 As shown, the pulse discrimination unit may further include a seventeenth capacitor C17, an eighteenth capacitor C18, and a nineteenth capacitor C19. The power supply of the first comparator U5 is connected to the third DC voltage. The power supply terminal of the first comparator U5 is grounded through the seventeenth capacitor C17. The eighteenth capacitor C18 and the nineteenth capacitor C19 are connected in parallel with the seventeenth capacitor C17. The seventeenth capacitor C17, the eighteenth capacitor C18, and the nineteenth capacitor C19 constitute a low-pass filter circuit to filter the third DC voltage, which helps to improve the output signal-to-noise ratio.

[0045] The noise discrimination unit is connected to the main amplification unit 3. The noise discrimination unit is used to identify the noise in the second amplified signal and output a second counting signal to determine the amount of noise in the second amplified signal.

[0046] Furthermore, such as Figure 4 As shown, the noise discrimination unit may include a second comparator U6, an eighteenth resistor R18, a nineteenth resistor R19, a twentieth resistor R20, a twenty-first resistor R21, and a fourteenth capacitor C14. The non-inverting input of the second comparator U6 is connected to the main amplifier unit 3 to receive the second amplified signal. One inverting input of the second comparator U6 is grounded via the nineteenth resistor R19 and the twentieth resistor R20, while the other inverting input is connected to a second DC voltage via the eighteenth resistor R18. The output of the second comparator U6 is connected to the first terminal of the twenty-first resistor R21. The eighteenth resistor R18, the nineteenth resistor R19, and the twentieth resistor R20 constitute a voltage divider circuit that divides the second DC voltage into a second divided voltage signal. The second comparator U6 compares the second amplified signal with the second divided voltage signal and outputs a second counting signal through the second terminal of the twenty-first resistor R21. The fourteenth capacitor C14 is connected between the inverting input of the second comparator U6 and ground to suppress high-frequency noise.

[0047] In this embodiment, when noise arrives, the voltage at the non-inverting input of the second comparator U6 is greater than the second voltage divider signal. At this time, the output of the second comparator U6 outputs a high level until the noise completely passes through, after which the second comparator U6 outputs a low level. Valid pulses are characterized by stable voltage amplitude and pulse width. After the detection signal passes through the preceding units (especially the filtering and shaping unit 2), most of the noise superimposed on the detection signal is filtered out. The remaining noise is usually interference caused by minor vibrations (typically originating from equipment vibration). Therefore, noise has a voltage amplitude significantly smaller than the valid pulse voltage amplitude. Based on this characteristic, setting the second voltage divider signal to a suitable value smaller than the first voltage divider signal is beneficial for the pulse discrimination unit to distinguish normal pulses and for the noise discrimination unit to distinguish noise. In other words, when the counter detects a high-level pulse output by the second comparator U6, it increments the total noise count by one. Further, by subtracting the total noise count from the total number of pulses to be counted, the total number of nuclear radiation particles can be obtained.

[0048] Due to the asymmetry in the internal structure and external circuitry of the first comparator U5 and the second comparator U6, an asymmetry in noise gain exists between the input ports (typically, the noise gain of the inverting input is slightly greater than that of the non-inverting input). Therefore, the processing capabilities for high-frequency signals differ when the reference voltage (i.e., the first and second voltage divider signals) is applied to the non-inverting and inverting inputs. In the first comparator U5, applying the second amplified signal through the inverting input fully utilizes its higher noise gain, helping to more accurately identify and count the pulses to be counted. In the second comparator U6, since the object to be identified is noise, which is a component of the second amplified signal, applying the second amplified signal through the non-inverting input effectively avoids the influence of other signals, helping to more accurately identify the noise within the second amplified signal.

[0049] It should be noted that the first to third DC voltages in this invention can be provided by existing voltage regulator circuits, which will not be elaborated here.

[0050] In some embodiments, the signal conditioning circuit may further include a counter connected to the discrimination unit, the counter being used to calculate the number of nuclear radiation particles based on the counting signal.

[0051] The present invention also provides a nuclear radiation detection device, including the signal conditioning circuit provided in the embodiments of the present invention.

[0052] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0053] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0054] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly by hardware, a software module executed by a processor, or a combination of both. The software module can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0055] It is understood that the above embodiments only illustrate preferred embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can freely combine the above technical features without departing from the concept of the present invention, and can also make several modifications and improvements, all of which fall within the protection scope of the present invention. Therefore, all equivalent transformations and modifications made with respect to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A signal conditioning circuit applied to a nuclear radiation detection device, the nuclear radiation detection device comprising a detector for detecting nuclear radiation particles and outputting a detection signal, characterized in that, The signal conditioning circuit includes: A preamplifier unit is used to amplify and isolate the detection signal and output a first amplified signal; A filtering shaping unit, connected to the preamplifier unit, is used to condition the first amplified signal into a narrow pulse signal. The main amplification unit, connected to the filter shaping unit, is used to condition the narrow pulse signal into a second amplified signal. The discrimination unit, connected to the main amplification unit, is used to discriminate the pulses to be counted and noise in the second amplified signal, and output a counting signal representing the number of pulses to be counted and the number of noise in the second amplified signal.

2. The signal conditioning circuit according to claim 1, characterized in that, The preamplifier unit includes: A preamplifier is used to amplify the detection signal and output a first amplified signal; A voltage follower, connected to the preamplifier, is used to isolate the first amplified signal.

3. The signal conditioning circuit according to claim 2, characterized in that, The preamplifier includes a first operational amplifier U1, a first capacitor C1, a second capacitor C2, a third capacitor C3, a first resistor R1, and a second resistor R2; The inverting input of the first operational amplifier U1 is connected to the detection signal via the first capacitor C1. The inverting input of the first operational amplifier U1 is connected to the output of the first operational amplifier U1 via the second capacitor C2. The non-inverting input of the first operational amplifier U1 is connected to a first DC voltage via the second resistor R2. The non-inverting input of the first operational amplifier U1 is also grounded via the third capacitor C3. The output of the first operational amplifier U1 outputs the first amplified signal. The first operational amplifier U1, the first capacitor C1, the second capacitor C2, and the second resistor R2 constitute a first amplification circuit. The first amplification circuit provides a bias voltage to the detection signal through the first DC voltage and amplifies the AC component in the detection signal. The first resistor R1 is connected in parallel with the second capacitor C2 so that the first amplifier circuit can establish a stable operating point.

4. The signal conditioning circuit according to claim 1, characterized in that, The filter shaping unit includes a third operational amplifier U3, a fourth resistor R4, a fifth resistor R5, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a fifth capacitor C5, a sixth capacitor C6, a seventh capacitor C7, an eighth capacitor C8, a ninth capacitor C9, and a tenth capacitor C10. The inverting input of the third operational amplifier U3 is connected to the first terminal of the fourth resistor R4 via the sixth capacitor C6 and the fifth resistor R5. The second terminal of the fourth resistor R4 is connected to the preamplifier unit. The inverting input of the third operational amplifier U3 is also connected to the first terminal of the fourth resistor R4 via the fifth capacitor C5. The inverting input of the third operational amplifier U3 is also connected to the output terminal of the third operational amplifier U3 via the seventh resistor R7. The seventh capacitor C7 is connected in parallel with the seventh resistor R7. The non-inverting input of the third operational amplifier U3 is connected to the first DC voltage via the eighth resistor R8 and grounded via the eighth capacitor C8. The output terminal of the third operational amplifier U3 is connected to the first terminal of the tenth resistor R10 via the ninth resistor R9 and the tenth capacitor C10. The node formed by the connection of the ninth resistor R9 and the tenth capacitor C10 is grounded via the ninth capacitor C9. The second terminal of the tenth resistor R10 is connected to the main amplifier unit.

5. The signal conditioning circuit according to claim 1, characterized in that, The main amplification unit includes a fourth operational amplifier U4, an eleventh capacitor C11, an eleventh resistor R11, and a twelfth resistor R12; The inverting input of the fourth operational amplifier U4 is connected to the filtering and shaping unit. The inverting input of the fourth operational amplifier U4 is connected to the output of the fourth operational amplifier U4 via the eleventh resistor R11. The eleventh capacitor C11 is connected in parallel with the eleventh resistor R11. The non-inverting input of the fourth operational amplifier U4 is connected to the first DC voltage via the twelfth resistor R12. The fourth operational amplifier U4, the eleventh resistor R11, and the twelfth resistor R12 constitute a second amplification circuit for amplifying the amplitude of the narrow pulse signal. The second amplification circuit outputs the second amplified signal through the output of the fourth operational amplifier U4.

6. The signal conditioning circuit according to claim 5, characterized in that, The main amplification unit also includes a twelfth capacitor C12 and a thirteenth resistor R13; The twelfth capacitor C12 is connected in parallel with the eleventh resistor R11 to suppress high-frequency noise and prevent high-frequency oscillation. The thirteenth resistor R13 is connected between the output of the fourth operational amplifier U4 and the discrimination unit to increase the output impedance of the second amplified signal.

7. The signal conditioning circuit according to any one of claims 1 to 6, characterized in that, The screening unit includes: The pulse to be counted discrimination unit is connected to the main amplification unit and is used to discern the pulses to be counted in the second amplified signal and output a first counting signal for determining the number of the pulses to be counted. The noise discrimination unit, connected to the main amplification unit, is used to discriminate noise in the second amplified signal and output a second counting signal to determine the amount of noise in the second amplified signal.

8. The signal conditioning circuit according to claim 7, characterized in that, The pulse discrimination unit includes a first comparator U5, a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16, a seventeenth resistor R17, and a thirteenth capacitor C13; The inverting input of the first comparator U5 is connected to the main amplification unit to receive the second amplified signal. The non-inverting input of the first comparator U5 is connected to the ground via the sixteenth resistor R16 and to the second DC voltage via the fifteenth resistor R15 and the fourteenth resistor R14. The output of the first comparator U5 is connected to the first terminal of the seventeenth resistor R17. The fourteenth resistor R14, the fifteenth resistor R15, and the sixteenth resistor R16 constitute a voltage divider circuit that divides the second DC voltage into a first voltage divider signal. The first comparator U5 compares the second amplified signal with the first voltage divider signal and outputs the first counting signal through the second terminal of the seventeenth resistor R17. The thirteenth capacitor C13 is connected in parallel with the sixteenth resistor R16 to suppress high-frequency noise.

9. The signal conditioning circuit according to claim 8, characterized in that, The noise discrimination unit includes a second comparator U6, an eighteenth resistor R18, a nineteenth resistor R19, a twentieth resistor R20, a twenty-first resistor R21, and a fourteenth capacitor C14; The non-inverting input of the second comparator U6 is connected to the main amplification unit to receive the second amplified signal. The inverting input of the second comparator U6 is connected to the second DC voltage via the nineteenth resistor R19 and the twentieth resistor R20, and via the eighteenth resistor R18. The output of the second comparator U6 is connected to the first terminal of the eleventh resistor R21. The eighteenth resistor R18, the nineteenth resistor R19, and the twentieth resistor R20 constitute a voltage divider circuit that divides the second DC voltage into a second voltage divider signal. The second comparator U6 compares the second amplified signal with the second voltage divider signal and outputs the second counting signal through the second terminal of the eleventh resistor R21. The fourteenth capacitor C14 is connected between the inverting input of the second comparator U6 and ground to suppress high-frequency noise.

10. A nuclear radiation detection device, characterized in that, Includes the signal conditioning circuit as described in any one of claims 1 to 9.

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