High-integration-level signal reading module for neutron proportional counter tube

Abstract

The invention provides a high-integration-level signal reading module for a neutron proportional counter tube, and belongs to the technical field of neutron detection, the high-integration-level signal reading module comprises stacked double-layer circuit boards, and the upper circuit board and the lower circuit board are connected through pin interfaces; the upper circuit board is provided with a signal processing circuit which is used for reading, amplifying, discriminating and shaping signals of the neutron proportional counter tube. The lower-layer circuit board is provided with a positive and negative dual-power-supply support circuit which provides + / -3.3 V power supply support for the signal processing circuit of the upper-layer circuit board. The module supplies power through the lower-layer power panel, and the lower-layer circuit board supplies positive and negative power to the upper-layer circuit board after completing power conversion. Signals are input through the IPX interface of the upper-layer circuit board and are output through the other IPX interface after being processed. The charge sensitive pre-amplifier, the broadband voltage amplifier, the pulse discriminator circuit, the pulse shaping circuit and the power management module are integrated in the same module, so that the real integrated design is realized.

Description

Technical Field

[0001] The present invention provides a highly integrated signal readout module for a neutron proportional counter tube, belonging to the technical field of neutron detection. Background Art

[0002] The application of neutron detection technology in modern science and technology has been widely penetrated into many fields such as energy, medical treatment, industry, national defense, and basic scientific research. In these core national industries, neutron technology plays an irreplaceable key role. For example, in nuclear power generation, neutron detection is used for the monitoring and control of reactors; in the medical field, such as neutron radiotherapy, accurate neutron dose monitoring is crucial; in industrial non-destructive testing, neutron imaging can be used to detect the internal structure of complex materials; while in the field of national defense and security, neutron detectors are relied on for the detection of nuclear materials and radiation monitoring.

[0003] Due to the radioactivity of neutron beams, neutron radiation may pose a threat to human health. Therefore, to ensure the safe application of nuclear technology, the detection and acquisition of neutron energy spectra and the accurate monitoring of neutron doses have become key technical links that need to be urgently solved in the development of various industries.

[0004] In the design of neutron detectors, the neutron proportional counter tube is a common detection medium, and it detects neutrons through the following principle: when neutrons enter the sensitive volume of the detector, they react with the atomic nuclei in the detection medium, such as (n,α) or (n,p) reactions, thereby generating secondary charged particles. These charged particles are quickly collected under the action of high voltage and form a readable nuclear pulse signal in the external circuit. This detection principle makes the proportional counter have high sensitivity and reliability in neutron radiation monitoring.

[0005] Although the existing neutron proportional counter technology has been relatively mature, there are still various challenges in the signal readout and processing circuits:

[0006] 1. Low integration and insufficient flexibility: Currently, the signal readout circuits of neutron detectors on the market are usually tailored for specific usage scenarios and are highly coupled with other functional modules. Although this specialized design can meet the requirements of a single scenario, it is difficult to flexibly adjust once the application environment changes. For example, although Amptek's solution has made certain attempts in modularization, its functional integration is still insufficient, and users need to design or purchase additional modules separately to achieve complete signal processing functions such as signal discrimination and pulse shaping. This not only increases the complexity of the system but also increases the difficulty of subsequent maintenance and fault troubleshooting.

[0007] 2. Large in size and difficult to be portable: Although the charge-sensitive preamplifier of ORTEC company has good sensitivity, due to its large size, it is difficult to be applied to portable detection devices. In addition, its function is single, and subsequent signal processing modules (such as pulse discrimination and shaping) still need to rely on external circuits or independent devices to achieve. This design not only occupies more space and power consumption, but also increases the integration difficulty of the system.

[0008] 3. Complex circuit design and difficult to maintain: The signal processing system of existing neutron detectors usually consists of multiple discrete modules, with complex circuit structure, many interfaces, and is vulnerable to the influence of external electromagnetic interference, reducing the accuracy and reliability of signal processing. This complexity increases the debugging and maintenance costs of the system, and at the same time limits the adaptability and scalability of the system. Summary of the Invention

[0009] To solve the above technical problems, the present invention proposes a highly integrated signal readout module for neutron proportional counters. Through highly integrated modular design and optimized circuit layout, the present invention overcomes the deficiencies of low integration, large size, and single function in the prior art, greatly improves the efficiency and reliability of the neutron detection system, and at the same time greatly reduces the weight and volume in portable applications. This solution provides a more efficient and reliable technical path for neutron proportional counter signal processing and has broad application prospects.

[0010] The specific technical solution is as follows:

[0011] A highly integrated signal readout module for neutron proportional counters, including a stacked double-layer circuit board, and connecting the upper and lower circuit boards through a pin interface;

[0012] The upper circuit board is provided with a signal processing circuit for realizing the reading, amplification, discrimination, and shaping of neutron proportional counter signals;

[0013] The lower circuit board is provided with a positive and negative dual-power support circuit to provide ±3.3V power support for the signal processing circuit on the upper circuit board.

[0014] The module is powered by the lower power supply board. After the lower circuit board completes power conversion, it provides positive and negative power supplies to the upper circuit board. The signal is input through the IPX interface on the upper circuit board. After signal processing is completed, it is output through another IPX interface.

[0015] The positive and negative power supplies of the lower circuit board adopt power chips, supporting 2.7V to 5.5V voltage input, and ±1.5V to ±5V dual-channel independent adjustable and low-noise positive and negative outputs.

[0016] The signal processing circuit on the upper circuit board includes a preamplification circuit, a signal main amplification circuit, a pulse discrimination circuit, and a pulse shaping circuit;

[0017] The preamplifier of the original signal input preamplification circuit completes the preliminary amplification and impedance conversion of the signal, improving the signal-to-noise ratio of the signal; the processed signal is input from the preamplifier of the preamplification circuit to the signal amplifier of the signal main amplification circuit, amplifying the pulse signal to an amplitude that can be processed by the subsequent pulse discrimination circuit and further improving the signal-to-noise ratio; the pulse discrimination circuit is a hysteresis comparator, converting the analog signal into high and low level signals, and the pulse discrimination circuit is provided with a comparison voltage by a voltage reference chip to ensure the stability of the voltage; the high and low level signals pass through the monostable flip-flop of the pulse shaping circuit and are shaped into digital level signals with consistent pulse widths.

[0018] Specifically:

[0019] The preamplifier of the preamplification circuit takes the OPA354 operational amplifier as the core, and a 1pF feedback capacitor and a feedback resistor jointly constitute a capacitive-resistive feedback charge-sensitive preamplifier.

[0020] The main amplifier in the signal main amplification circuit is an AD8065 chip.

[0021] The core of the pulse discrimination circuit is a hysteresis comparator, realizing the signal conversion from an analog signal to a level signal. The TLV3201 high-speed comparator is used as the core device of the command comparator, and a reference voltage chip is used as the input of the non-inverting terminal.

[0022] In the pulse shaping circuit, a stage of monostable flip-flop is added at the back end of the hysteresis comparator. After receiving the level change of the previous-stage hysteresis comparator, the monostable flip-flop jumps from the stable low-level state to the unstable high-level state, maintains for a period of time and then returns to the stable low-level state.

[0023] The present invention is specifically used for the signal readout and processing of neutron proportional counters. Compared with the existing solutions, the present invention integrates a charge-sensitive preamplifier, a broadband voltage amplifier, a pulse discrimination circuit, a pulse shaping circuit and a power management module in the same module, realizing an integrated design in the true sense. Its main technical advantages include:

[0024] 1. Modularity and high integration: By integrating each functional module into a compact module, the design of the signal processing system of the neutron detector is significantly simplified, and the external connection and debugging work are reduced. This not only improves the reliability of the system, but also enhances the flexibility and portability of the detector.

[0025] 2. Small size, suitable for portable applications: The present invention adopts an optimized circuit layout and a miniaturized package, greatly reducing the volume of the entire module, making it suitable for application in portable neutron detection equipment. Compared with the larger-sized solutions on the market, the present invention can better meet the application requirements of being lightweight and mobile.

[0026] 3. Single power supply to reduce power consumption: By integrating a power management circuit, this module only requires a single power supply, greatly simplifying the system design and effectively reducing the overall power consumption, making it suitable for battery-powered portable devices.

[0027] 4. Anti-interference design to improve signal processing stability: High-performance RF connectors are designed at the signal input and output interfaces, enhancing the anti-interference ability of the system and ensuring high-precision signal processing ability even in complex electromagnetic environments. Description of the Drawings

[0028] Figure 1 is the physical diagram of the module of the present invention;

[0029] Figure 2 is the power supply schematic diagram of the present invention;

[0030] Figure 3 is the functional architecture diagram of the signal processing circuit of the present invention;

[0031] Figure 4 is the circuit diagram of the capacitive-resistive feedback charge-sensitive preamplifier of the present invention;

[0032] Figure 5 is the circuit diagram of the signal main amplifier of the present invention;

[0033] Figure 6 is the circuit diagram of the hysteresis comparator (pulse discrimination circuit) of the present invention;

[0034] Figure 7 is the circuit diagram of the pulse shaping circuit of the present invention. Detailed Embodiments

[0035] A highly integrated signal readout module for a neutron proportional counter tube provided by the present invention adopts a double-layer circuit board stack, and the upper and lower circuit boards are tightly connected through a pin interface to form a complete signal processing module; as Figure 1 shown.

[0036] The upper circuit board is a signal processing circuit for realizing the reading, amplification, discrimination and shaping of the neutron proportional counter tube signal; the lower circuit board is a positive and negative dual-power support circuit for providing ±3.3V power support for the upper signal processing circuit.

[0037] Both the upper and lower boards are 3cm × 3cm. After the whole board is stacked, it forms a complete module. The module is powered by the lower power supply board. After the power supply board completes the power conversion, it provides positive and negative power supplies to the upper signal processing board. The signal is input through the IPX interface on the upper layer. After the signal processing is completed, it is output through another IPX interface.

[0038] Detailed introduction:

[0039] For the positive and negative power supplies of the lower - layer circuit board, dedicated power chips are used, which support a voltage input of 2.7V to 5.5V and have dual - independent adjustable and low - noise positive and negative outputs of ±1.5V to ±5V. In the present invention, the two - way outputs are set to +3.3V and -3.3V. Its schematic diagram is as Figure 2 shown.

[0040] The function of the signal - processing circuit on the upper - layer circuit board consists of four parts, namely the pre - amplifier circuit, the main signal amplifier circuit, the pulse discrimination circuit, and the pulse shaping circuit. Its functional architecture is as Figure 3 shown. The original signal is input into the pre - amplifier circuit to complete the preliminary amplification and impedance conversion of the signal, improving the signal - to - noise ratio of the signal; the processed signal is input from the pre - amplifier circuit to the main signal amplifier circuit, which amplifies the pulse signal to an amplitude that can be processed by the subsequent pulse discrimination circuit and further improves the signal - to - noise ratio; the pulse discrimination circuit is a hysteresis comparator, which can convert the analog signal into high - and - low - level signals. The pulse discrimination circuit is provided with a comparison voltage by a voltage reference chip to ensure the stability of the voltage; the high - and - low - level signals are shaped into digital - level signals with a consistent pulse width via a monostable flip - flop.

[0041] Specifically:

[0042] Realization of the pre - amplifier circuit: The pre - amplifier is centered around the OPA354 operational amplifier. The charge is integrated through a 1pF feedback capacitor, and the feedback resistor is R2. The two together form a resistor - capacitor feedback - type charge - sensitive pre - amplifier, as Figure 4 shown.

[0043] Realization of the main signal amplifier circuit: The main amplifier is the AD8065 chip, and the amplification factor is (R6 + R7) / R7. In this design, the amplification factor is set to 3 times. The design diagram is as Figure 5 shown.

[0044] Realization of the pulse discrimination circuit: The core of the pulse discrimination circuit is a hysteresis comparator, which can realize the signal conversion from analog signal to level signal. The hysteresis comparator has upper and lower double thresholds and has good anti - interference performance. In this design, the TLV3201 high - speed comparator is used as the core device of the hysteresis comparator. At the same time, to stabilize the upper and lower thresholds, a reference voltage chip is selected as the input of the non - inverting terminal in the design, as Figure 6 shown.

[0045] Implementation of the pulse shaping circuit: Since the pulse width of the output level of the hysteresis comparator is unstable, a monostable flip-flop is added at the back end of the hysteresis comparator. In the present invention, after receiving the level change of the previous-stage hysteresis comparator, the monostable flip-flop will jump from the stable low-level state to the unstable high-level state, and return to the stable low-level state after maintaining for a period of time. The duration of the high-level pulse is determined by C4 and R14. In the present invention, the pulse duration is set to 6 μs, as Figure 7 shown.

Claims

1. A highly integrated signal readout module for a neutron proportional counter tube, characterized in that: It includes a stacked double-layer circuit board, and the upper and lower layers of the circuit board are connected through a pin interface; The upper circuit board is provided with a signal processing circuit for realizing the reading, amplification, identification and shaping of the neutron proportional counter tube signal; The lower circuit board is equipped with a positive and negative dual power supply support circuit to provide ±3.3V power supply support for the signal processing circuit of the upper circuit board; The module is powered by the lower power board. After the lower circuit board completes the power conversion, it provides positive and negative power to the upper circuit board. The signal input is input through the IPX interface of the upper circuit board. After the signal processing is completed, it is output through another IPX interface.

2. A highly integrated signal readout module for a neutron proportional counter tube according to claim 1, characterized in that: The positive and negative power supplies of the lower circuit board adopt a power chip, which supports 2.7V to 5.5V voltage input, ±1.5V to ±5V dual-channel independently adjustable, low-noise positive and negative output.

3. A highly integrated signal readout module for a neutron proportional counter tube according to claim 1, characterized in that: The signal processing circuit of the upper circuit board includes a preamplifier circuit, a signal main amplifier circuit, a pulse discrimination circuit and a pulse shaping circuit; The original signal is input into the preamplifier of the preamplifier circuit to complete the initial amplification and impedance conversion of the signal, thereby improving the signal-to-noise ratio of the signal; the processed signal is input into the signal amplifier of the main signal amplifier circuit by the preamplifier of the preamplifier circuit, thereby amplifying the pulse signal to an amplitude that can be processed by the subsequent pulse discrimination circuit, thereby further improving the signal-to-noise ratio; the pulse discrimination circuit is a hysteresis comparator, which converts the analog signal into high and low level signals, and the pulse discrimination circuit is provided with a comparison voltage by a voltage reference chip to ensure voltage stability; the high and low level signals are shaped into digital level signals with consistent pulse widths via the monostable trigger of the pulse shaping circuit.

4. A highly integrated signal readout module for a neutron proportional counter tube according to claim 3, characterized in that: The preamplifier of the preamplifier circuit is based on the OPA354 operational amplifier, and a 1pF feedback capacitor and a feedback resistor together constitute a resistance-capacitance feedback charge-sensitive preamplifier.

5. The highly integrated signal readout module for a neutron proportional counter tube according to claim 3, characterized in that: The main amplifier in the signal main amplification circuit is an AD8065 chip.

6. The highly integrated signal readout module for a neutron proportional counter tube according to claim 3, characterized in that: The core of the pulse discrimination circuit is a hysteresis comparator, which realizes the signal conversion from analog signal to level signal; the TLV3201 high-speed comparator is used as the core device of the command comparator, and the reference voltage chip is used as the input of the in-phase terminal.

7. The highly integrated signal readout module for a neutron proportional counter tube according to claim 3, characterized in that: In the pulse shaping circuit, a monostable trigger is added at the rear end of the command comparator. After receiving the level change of the front hysteresis comparator, the monostable trigger jumps from a stable low level state to an unstable high level state, and returns to a stable low level state after maintaining it for a period of time.

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