A signal processing system and method for a radiation detector based on a MOS transistor

Abstract

The present invention relates to a radiation detector signal processing system and method based on MOS tubes. The system includes: a power supply generation module, an analog signal processing module and a digital signal acquisition processing module. The power supply generation module provides a new power supply method, converting positive voltage into negative voltage to power the last stage DY8 of the photomultiplier tube dynode; the analog signal processing module converts the negative current pulse signal into a voltage difference signal; the digital signal acquisition processing module collects the analog signal processing module signal and converts it into a digital signal for identification and processing. The present invention solves the noise caused by the coupling capacitor used in the positive high voltage power supply mode to separate the positive high voltage from the detector output signal, and solves the problem of ballistic loss, baseline offset and noise introduced by complex signal processing in traditional nuclear electronic circuits.

Description

Technical Field

[0001] The present invention relates to the technical field of nuclear electronics, and in particular to a radiation detector signal processing system and method based on MOS tubes. Background Art

[0002] At present, the application of microelectronics technology in the field of nuclear electronics, especially the application of ASIC technology, has brought nuclear electronics technology into a new stage, that is, readout chipization, where all functions can be fully realized in a custom chip. Nuclear signal measurement belongs to the category of weak signal detection. According to the Friis formula, the preamplifier is the first-stage amplifier of the nuclear radiation measurement system, and its noise performance determines the detection resolution of the front-end electronics; that is, the noise level of the preamplifier directly determines the weakness of the signal that can be detected by the entire nuclear radiation measurement system. Therefore, low-noise preamplifiers are an important development direction for nuclear electronics, especially front-end nuclear electronics. In addition, nuclear electronics based on analog signal processing are usually implemented using complex analog circuits. With the increasing development of digital signal processing technology and semiconductor technology, ADC technology has also developed rapidly, and its performance indicators are becoming more and more superior. Nuclear electronics based on digital signal processing has begun to be put on the agenda. At present, the circuit structure of nuclear electronics based on modern digital signal processing basically adopts the front-end electronics system (preamplifier, pole-zero phase cancellation, filter shaping, main amplifier) ​​+ ADC architecture. Therefore, low-noise front-end electronics system and high-speed data acquisition are two directions for the future development of nuclear electronics.

[0003] The signal processing process in the classic nuclear electronic circuit mainly includes preamplifier, spectrometer amplifier, multi-channel analyzer, etc. The processing process is complicated, and it is easy to introduce noise during the processing and the ballistic loss problem cannot be avoided. Figure 8 The figure below shows the signal waveform of the classic nuclear electronic circuit signal processing circuit and related processes.

[0004] The physical characteristics of radiation sensors are described as the integration of the current source over time. The charge generated is proportional to the energy of the particle entering the detector. Classical nuclear electronic circuits usually integrate the current source over time and transfer the charge product to an integrating capacitor. At the same time, a large discharge resistor is used to discharge the accumulated charge. However, since the value of the discharge resistor is large and fixed, it is very likely to cause pulse accumulation when many rays enter the detection material at the same time, that is, only particle pulses of a certain frequency are allowed, and it will cause problems such as ballistic loss.

[0005] The working principle of scintillation radiation detector is that scintillating material emits photons after absorbing radiation energy, and the photomultiplier tube converts the photons into electrons and multiplies the electrons into a large number of electrons by a constant factor, so that the radiation detector outputs a current pulse signal whose charge is proportional to the radiation energy. The classic radiation detector signal processing method is to use RC integration circuit and amplifier circuit to integrate and amplify the current pulse signal at the preamplifier. Since the resistance in the RC integration circuit will introduce an exponential discharge coefficient, the voltage signal waveform obtained by integration has a serious tail. This tail is very likely to cause pulse accumulation and inevitably cause problems such as ballistic loss. Therefore, the classic radiation detector signal processing method uses a series of filtering and shaping circuits to correct the voltage signal waveform. Considering that the filtering and shaping circuit is easy to introduce electronic noise, the design of the classic radiation detector signal processing system is extremely complex. Summary of the invention

[0006] In order to overcome the shortcomings of the prior art, the purpose of the present invention is to provide a radiation detector signal processing system and method based on MOS tubes. The present invention solves the noise caused by the coupling capacitor used to separate the positive high voltage from the detector output signal in the positive high voltage power supply mode, and at the same time solves the problems of ballistic loss, baseline offset and noise introduced by complex signal processing in traditional nuclear electronic circuits.

[0007] To achieve the above object, the present invention provides the following solution: To achieve the above object, the present invention provides the following solution:

[0008] A radiation detector signal processing system based on MOS tubes, comprising: a photomultiplier tube, a power generation module, an analog signal processing module and a digital signal acquisition processing module;

[0009] The photomultiplier tube comprises: a cathode K of the photomultiplier tube, an anode P of the photomultiplier tube, a multiplier electrode and a voltage divider circuit;

[0010] The power supply generation module includes: an external power supply, a first voltage stabilizer, a second voltage stabilizer, a third voltage stabilizer, a fourth voltage stabilizer, a boost circuit, a shaping filter circuit, and a power isolation module;

[0011] The external power source is connected to the first voltage stabilizer, so that the external power source is stabilized by the first voltage stabilizer to obtain a first DC voltage source;

[0012] The first DC voltage source is connected to the second voltage stabilizer; the DC voltage source is stabilized by the second voltage stabilizer to obtain a second DC voltage source;

[0013] The first DC voltage source is connected to the power isolation module and is used to generate a first isolated DC voltage source;

[0014] The first isolated DC voltage source is connected to the third voltage stabilizer, and the first DC isolated DC voltage source is stabilized by the third voltage stabilizer to obtain a second module power supply;

[0015] The first isolated DC voltage source is connected to the fourth voltage stabilizer, and the first DC isolated DC voltage source is stabilized by the fourth voltage stabilizer to obtain a third module power supply;

[0016] The first DC voltage source generates a positive high voltage power supply through the boost circuit and the shaping filter circuit;

[0017] An anode of the positive high-voltage power source generated by the first DC voltage source is connected to the ground of the first isolated DC voltage source, and is used to convert the positive high-voltage power source into a negative high-voltage power source;

[0018] The negative high voltage is connected to the last stage DY8 of the dynode of the photomultiplier tube, and is used to provide the voltage required by the dynode. The ground of the first DC voltage source is connected to the cathode K of the photomultiplier tube.

[0019] The power isolation module includes: a power isolator;

[0020] The power isolator is used to isolate the ground of the 5V DC power supply and the ground of the 5V isolated DC power supply;

[0021] The analog signal processing module includes: a MOS tube, a first capacitor and an amplifier;

[0022] Pin 2 of the MOS tube Q1 is connected to the anode of the power supply VDDA, pin 3 of the MOS tube Q1 is connected to the amplifier, the first capacitor is connected in parallel between pins 2 and 3 of the MOS tube Q1, and a negative current pulse signal is connected to pin 3 of Q1;

[0023] The first capacitor is charged by the MOS tube Q1, and different negative electric pulse signals pass through the first capacitor, the first capacitor is discharged, a voltage drop is obtained to obtain a voltage difference signal, and the voltage difference is amplified to obtain an amplified voltage difference;

[0024] The digital signal acquisition and processing module includes: a chip and a digital isolator;

[0025] The chip is connected to the amplifier and the digital isolator respectively, and is used for collecting voltage difference analog signals, converting the analog signals into digital signals, processing the digital signals, and finally transmitting data.

[0026] Preferably, the chip includes a PeakClear output signal;

[0027] The PeakClear output signal is connected to pin No. 13 of the chip, and the PeakClear output signal is connected to pin No. 1 of the MOS tube Q1 to control the conduction of the MOS tube Q1 to charge the first capacitor.

[0028] Preferably, pins 2 and 3 of the digital isolator are connected to pins 20 and 19 of the chip respectively;

[0029] Pin 8 of the digital isolator is connected to the first DC voltage source, pin 1 of the digital isolator is connected to the power supply of the third module, pin 5 of the digital isolator is connected to the ground of the first DC voltage source, and pin 4 of the digital isolator is connected to the ground of the first isolated DC voltage source. The digital isolator is used to isolate the ground of the first DC voltage source from the ground of the first isolated DC voltage source to facilitate stable data transmission.

[0030] Preferably, the boost circuit comprises: a transformer and a converter;

[0031] The transformer and the converter are respectively connected to the first DC voltage source, and are used to convert and boost the first DC voltage source.

[0032] Preferably, it includes:

[0033] The second module power supply is used to supply power to the analog signal processing module;

[0034] The third module power supply is a 3V3 power supply, which is used to supply power to the digital signal acquisition and processing module.

[0035] A radiation detector signal processing method based on MOS tube, characterized by comprising:

[0036] Using an external power source to obtain a first DC voltage source through voltage stabilization by a first voltage stabilizer;

[0037] The DC voltage source is stabilized by a second voltage stabilizer to obtain a second DC voltage source;

[0038] Using the first DC voltage source and the power isolation module to generate a first isolated DC voltage source;

[0039] The first DC isolation DC voltage source is stabilized by a third voltage stabilizer to obtain a second module power supply;

[0040] The third module power supply is obtained by stabilizing the first DC isolation DC voltage source through a fourth voltage stabilizer;

[0041] Using a first DC voltage source to generate a positive high voltage power supply via a boost circuit and a shaping filter circuit;

[0042] Connecting the anode of the positive high-voltage power source generated by the first DC voltage source to the ground of the first isolated DC voltage source to convert the positive high-voltage power source into a negative high-voltage power source;

[0043] Use negative high voltage to connect the last stage DY8 of the dynode of the photomultiplier tube to provide the voltage required by the dynode;

[0044] Use a power isolator to isolate the ground of the 5V DC power supply and the ground of the 5V isolated DC power supply;

[0045] The first capacitor is charged by the MOS tube Q1, and different negative electric pulse signals pass through the first capacitor, the first capacitor is discharged, and the voltage drop is obtained to obtain a voltage difference signal, and the voltage difference is amplified to obtain an amplified voltage difference;

[0046] The chip is used with an amplifier and a digital isolator to collect voltage difference analog signals, convert the analog signals into digital signals and process them, and finally transmit data.

[0047] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0048] The present invention provides a radiation detector signal processing system and method based on MOS tube, which uses a positive high voltage generated by a classical nuclear electronic circuit to be isolated from another power supply by a power isolation module, and then the positive electrode of the high voltage is connected to the cathode of another power supply. This method not only solves the noise, baseline offset and other related problems caused by the coupling capacitor used to separate the positive high voltage from the detector output signal in the positive high voltage power supply mode, but also has the advantages of simplicity and low cost compared to other negative high voltage circuits or power supplies; the present application abandons the method of processing detector signals in classical nuclear electronic circuits, but uses the switching characteristics and capacitance characteristics of MOS tubes to convert the current pulse signal of the detector into a voltage difference, and then uses a digital method to identify the signal. This method converts the signal into a voltage difference, simplifies the complex processing process of the signal (such as pre-amplification, pole-zero phase cancellation, filtering and shaping, etc.), and solves the problem of easy introduction of noise by electronic components in complex signal processing circuits; the present application uses a voltage difference to represent the energy of the ion for signal identification, which is different from the voltage representing the energy of the ion in the classical nuclear electronic circuit, and solves the problems of ballistic loss, statistical error and quantization error in the classical nuclear electronic circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0050] Figure 1 A negative high voltage generation flow chart of the system in the embodiment provided by the present invention;

[0051] Figure 2 A flowchart of analog signal processing of a system in an embodiment provided by the present invention;

[0052] Figure 3 A digital signal processing flow chart of a system in an embodiment provided by the present invention;

[0053] Figure 4 A schematic diagram showing the improvement of digital signal processing in the embodiment of the present invention;

[0054] Figure 5 A circuit structure diagram of a voltage module of a system in an embodiment of the present invention;

[0055] Figure 6 The PMT voltage divider circuit and signal output circuit in the embodiment provided by the present invention;

[0056] Figure 7 A structural diagram of an analog signal processing circuit of a system in an embodiment of the present invention;

[0057] Figure 8 A circuit structure diagram of a classic nuclear electronic circuit signal processing circuit in an embodiment provided by the present invention;

[0058] Fig. 9 A structural diagram of a digital signal processing circuit of a system in an embodiment of the present invention;

[0059] Fig.10 A flowchart of the working principle of the classical nuclear electronic circuit signal processing in the embodiment provided by the present invention;

[0060] Fig.11 The waveforms of the negative charge signal and the integrated capacitance signal output by the detector in the embodiment provided by the present invention;

[0061] Fig.12 The waveforms of PeakClear, detector negative charge output and integrated capacitance signal in the embodiment provided by the present invention.

[0062] Explanation of symbols:

[0063] U1: second voltage regulator; U2: chip; U4: digital isolator; U5: amplifier; U6: first voltage regulator; J10: power isolation module; U11: fourth voltage regulator; U12: third voltage regulator; Q1: MOS tube; C18: first capacitor; 5V_HV: first DC power supply; Vin_PRT: external power supply; 5V_MCU: first isolated DC power supply; VDDA: second module power supply; 3V3_MCU: third module power supply. DETAILED DESCRIPTION

[0064] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0065] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0066] The terms "first", "second", "third" and "fourth" in the specification and claims of the present application and the drawings are used to distinguish different objects rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a series of steps, processes, methods, etc. are not limited to the listed steps, but may optionally include steps that are not listed, or may optionally include other step elements inherent to these processes, methods, products or devices.

[0067] The purpose of the present invention is to provide a radiation detector signal processing system and method based on MOS tubes. The present invention solves the problems of noise and baseline offset caused by coupling capacitors used to separate positive high voltage from detector output signals in a positive high voltage power supply mode, and noise easily introduced by electronic components in complex signal processing circuits.

[0068] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0069] like Figure 1-12As shown, the present invention provides a radiation detector signal processing system based on MOS tube, characterized in that it includes: a photomultiplier tube, a power generation module, an analog signal processing module and a digital signal acquisition and processing module;

[0070] The photomultiplier tube comprises: a cathode K of the photomultiplier tube, an anode P of the photomultiplier tube, a multiplier electrode, and a voltage divider circuit;

[0071] The power supply generation module includes: an external power supply, a first voltage stabilizer, a second voltage stabilizer, a third voltage stabilizer, a fourth voltage stabilizer, a boost circuit, a shaping filter circuit, and a power isolation module;

[0072] The external power source is connected to the first voltage stabilizer, so that the external power source is stabilized by the first voltage stabilizer to obtain a first DC voltage source;

[0073] The first DC voltage source is connected to the second voltage stabilizer; the DC voltage source is stabilized by the second voltage stabilizer to obtain a second DC voltage source;

[0074] The first DC voltage source is connected to the power isolation module and is used to generate a first isolated DC voltage source;

[0075] The first isolated DC voltage source is connected to the third voltage regulator, and is used for obtaining a second module power supply by stabilizing the first DC isolated DC voltage source through the third voltage regulator, and the second module power supply is an analog power supply;

[0076] The first isolated DC voltage source is connected to the fourth voltage regulator, and is used for obtaining a third module power supply by stabilizing the first DC isolated DC voltage source through the fourth voltage regulator, wherein the third module power supply is a digital power supply;

[0077] The first DC voltage source generates a positive high voltage power supply through the boost circuit and the shaping filter circuit;

[0078] An anode of the positive high-voltage power source generated by the first DC voltage source is connected to the ground of the first isolated DC voltage source, and is used to convert the positive high-voltage power source into a negative high-voltage power source;

[0079] The negative high voltage is connected to the last stage DY8 of the dynode of the photomultiplier tube, and is used to provide the voltage required by the dynode. The ground of the first DC voltage source is connected to the cathode K of the photomultiplier tube.

[0080] The power isolation module includes: a power isolator;

[0081] The power isolator is used to isolate the ground of the 5V DC power supply and the ground of the 5V isolated DC power supply.

[0082] The specific process is as follows: Figure 5 As shown, the anode Vin_PRT of the external power supply is connected to the voltage regulator U6 to generate a 5V DC power supply (5V_HV), and the 5V DC power supply (5V_HV) is connected to the power isolation module J10. The ground of the power supply is connected to pin 1 of J10, and the anode of the power supply is connected to pin 2 of J10. At the same time, a capacitor is connected in series between the power anode access point of pin 2 of J10 and the ground of the power supply. A 5V isolated DC power supply (5V_MCU) is generated between pins 3 and 4 of J10. Pin 3 is the ground of the generated 5V isolated DC power supply (5V_MCU), and pin 4 is the anode of the generated 5V isolated DC power supply (5V_MCU). A capacitor is connected in series between pins 3 and 4. The anode PMT_HV_OUT of the positive high-voltage power supply obtained by the 5V DC power supply (5V_HV) through the boost circuit is connected to the ground of the 5V isolated DC power supply (5V_MCU), thereby converting the positive high voltage into a negative high voltage. The anode of the 5V DC power supply (5V_HV) is connected to the pin 8 of the digital isolator U4, and the ground of the 5V DC power supply (5V_HV) is connected to the pin 5 of the digital isolator U4. The power supply circuit part uses the power isolator to provide a new negative voltage generation method. The innovation of this method is to use the power isolator to generate a 5V isolated DC power supply (5V_MCU) isolated from the positive high-voltage DC power supply, and then connect the anode of the positive high-voltage DC power supply to the ground of the isolated 5V DC power supply (5V_MCU), thereby converting the positive high voltage into negative high voltage. At the same time, the digital isolator is used to eliminate the influence of the ground of the isolated 5V DC power supply connected to the positive high-voltage DC power supply on the communication between the system and the outside.

[0083] The analog signal processing module includes: a MOS tube, a first capacitor, and an amplifier;

[0084] Pin 2 of the MOS tube Q1 is connected to the anode of the power supply VDDA, pin 3 of the MOS tube Q1 is connected to the amplifier, pins 2 and 3 of the MOS tube Q1 are connected in parallel to the first capacitor, a negative current pulse signal is connected to pin 3 of the MOS tube Q1, and pin 1 of the MOS tube Q1 is connected to the PeakClear output signal to control the conduction of the MOS tube Q1 and charge the first capacitor;

[0085] The first capacitor is charged by the MOS tube Q1, discharged by the negative electric pulse signal, and a voltage drop is obtained to obtain a voltage difference signal; the amplifier amplifies the voltage difference signal;

[0086] The specific process is as follows: Figure 7As shown, Q1 is a MOS tube, Q1's pin 1 is connected to U2's pin 13, Q1's pin 2 is connected to the anode of the power supply VDDA, and capacitor C19 is connected between Q1's pin 2 and the ground of VDDA, and Q1's pin 3 is connected to U5's pin 3. Q1's pins 2 and 3 are connected in parallel to the first capacitor, and the negative current pulse signal PMT_signal output by the detector is connected to Q1's pin 3. U5's pin 1 is connected to U2's pin 5, and resistors R11 and R16 are connected in series to the circuit to determine the amplifier's gain. In the integration process of the negative charge signal output by the detector on the first integrating capacitor, considering the breakdown voltage of the capacitor, the integral voltage on the capacitor cannot be accumulated indefinitely. The analog signal processing circuit of the system utilizes the charging and discharging characteristics of the capacitor. When the negative current pulse signal output by the detector passes through the capacitor, the capacitor loses the corresponding amount of charge. The negative charge signal output by the detector is integrated on the first integrating capacitor to generate a negative voltage, thereby reducing the voltage on the first integrating capacitor, thus converting the negative charge signal into a changing voltage signal on the integrating capacitor C18. Each negative current pulse signal converted into a voltage difference signal will consume the corresponding amount of charge on the capacitor. In order to maintain sufficient charge on the capacitor at all times, the switching characteristics of the MOS tube Q1 are utilized to charge the first integrating capacitor with the power supply VDDA so that the voltage on the first integrating capacitor is equal to VDDA, thereby restoring the charge on the capacitor. Fig. 9As shown, PeakClear is a signal controlled and output by the chip, and PeakClear is connected to the 13th pin of the chip. A threshold Threshold and a fixed time period t2 are set manually. There are two cases when the negative rectangular pulse signal PeakClear is output from the 13th pin of the chip: the first case is that in the t2 time period, the voltage value on the first integral capacitor is less than the threshold Threshold after being amplified by the operational amplifier U5, and the chip will send out a negative rectangular pulse signal PeakClear; the second case is that in the t2 time period, the voltage value on the first integral capacitor is always greater than the threshold Threshold after being amplified by the operational amplifier U5, but when the time interval reaches t2. The chip will also send out a negative rectangular pulse signal PeakClear, which turns on the MOS tube, so that the voltage on the first integral capacitor is equal to VDDA. ADC_COMP_IN is the signal after the voltage signal on the first integral capacitor is amplified by the operational amplifier U5. ADC_COMP_IN is connected to the 5th pin of the chip. The chip performs analog-to-digital conversion on ADC_COMP_IN, and then processes the converted digital signal. At the same time, the chip judges the two situations of the negative rectangular pulse signal PeakClear output by pin 13 of the chip in the previous step according to the converted digital signal and the corresponding time, and judges whether to output the negative rectangular pulse signal through pin 13 to charge the first integral capacitor.

[0087] The digital signal acquisition and processing module includes: chip U2 and digital isolator;

[0088] The chip is connected to the amplifier and the digital isolator respectively, and is used for collecting voltage difference analog signals, converting the analog signals into digital signals, processing the digital signals, and finally transmitting data.

[0089] Further, pins 2 and 3 of the digital isolator are connected to pins 20 and 19 of the chip respectively;

[0090] Pin 8 of the digital isolator is connected to the first DC voltage source, pin 1 of the digital isolator is connected to the third module power supply, pin 5 of the digital isolator is connected to the ground of the first DC voltage source, pin 4 of the digital isolator is connected to the ground of the first isolated DC voltage source, and the digital isolator is used to isolate the ground of the first DC voltage source from the ground of the first isolated DC voltage source to facilitate stable data transmission;

[0091] Specifically: Fig. 9As shown, the 5V isolated DC power supply (5V_MCU) is connected to the regulator U11 to generate the power supply 3V3_MCU to power the module. Pin 1 of Q1 is connected to pin 13 of U2, and pin 1 of U5 is connected to pin 5 of U2. Pin 8 of U4 is connected to the anode of the 5V DC power supply (5V_HV), and the pin is connected to the ground of the 5V DC power supply (5V_HV) through capacitor C72. Pin 5 of U4 is connected to the ground of the 5V DC power supply (5V_HV). Pin 1 of U4 is connected to the anode of the power supply 3V3_MCU, and the pin is connected to the ground of the power supply 3V3_MCU through capacitor C9. Pin 2 of U4 is connected to pin 20 of U2, pin 3 of U4 is connected to pin 19 of U2, and pin 4 of U4 is connected to the ground of the power supply 3V3_MCU. The digital signal processing circuit of the system first uses U2 to digitize the signal, and then uses digital signal processing technology to process the digital signal. At the same time, using U4, the system communicates with the outside world and transmits processed signals.

[0092] Further, the boost circuit includes: a transformer and a converter;

[0093] The transformer and the converter are respectively connected to the first DC voltage source, and are used to convert and boost the first DC voltage source;

[0094] The model of the transformer is: Z2w, and the model of the converter is: LT3580.

[0095] Further, including:

[0096] The second module power supply supplies power to the analog signal processing module;

[0097] The third module power supply is a 3V3 power supply, which supplies power to the digital signal acquisition and processing module.

[0098] Further, including:

[0099] The model of the digital isolator is: ADuM1201AR.

[0100] This embodiment also provides a radiation detector signal processing method based on a MOS tube, including:

[0101] Using an external power source to obtain a first DC voltage source through voltage stabilization by a first voltage stabilizer;

[0102] The DC voltage source is stabilized by a second voltage stabilizer to obtain a second DC voltage source;

[0103] Using the first DC voltage source and the power isolation module to generate a first isolated DC voltage source;

[0104] The first DC isolation DC voltage source is stabilized by a third voltage stabilizer to obtain a second module power supply;

[0105] The third module power supply is obtained by stabilizing the first DC isolation DC voltage source through a fourth voltage stabilizer;

[0106] Using a first DC voltage source to generate a positive high voltage power supply via a boost circuit and a shaping filter circuit;

[0107] Connecting the anode of the positive high-voltage power source generated by the first DC voltage source to the ground of the first isolated DC voltage source to convert the positive high-voltage power source into a negative high-voltage power source;

[0108] Use negative high voltage to connect the last stage DY8 of the dynode of the photomultiplier tube to provide the voltage required by the dynode;

[0109] Use a power isolator to isolate the ground of the 5V DC power supply and the ground of the 5V isolated DC power supply;

[0110] The first capacitor is charged by the MOS tube Q1, and different negative electric pulse signals pass through the first capacitor, the first capacitor is discharged, and the voltage drop is obtained to obtain a voltage difference signal, and the voltage difference is amplified to obtain an amplified voltage difference;

[0111] The chip is used with an amplifier and a digital isolator to collect voltage difference analog signals, convert the analog signals into digital signals and process them, and finally transmit data.

[0112] The negative electrical pulse signal is converted into a voltage difference signal through the MOS tube switching characteristics; Figure 4 As shown, the peak extraction of quasi-Gaussian signals in traditional nuclear electronic circuits will introduce statistical errors, and quantization errors will be introduced in the process of digital signal processing of quasi-Gaussian signals. Compared with traditional nuclear electronic circuits, nuclear electronic circuits based on MOS tubes eliminate statistical errors and quantization errors by performing digital signal processing on the voltage difference signal (voltage difference = baseline - peak line).

[0113] Figure 6 The PMT voltage divider circuit and signal output circuit in the embodiment provided by the present invention are shown in this part. Figure 5 and Figure 7 The connection between them, K is the cathode of the photomultiplier tube, DY1 to DY8 are the dynodes, and P is the anode. The ground of PMT_HV_OUT and PMT_signal are connected together. The digital labels 1, 2, 3, etc. are the pins of the photomultiplier tube (PMT). PMT_HV_OUT provides voltage to the dynode of the photomultiplier tube (PMT) through a voltage divider circuit, and PMT_signal is the signal output by the photomultiplier tube (PMT).

[0114] Specifically: The system's workflow is as follows: Figure 1-4As shown, in the power supply circuit part, the external power supply passes through the voltage stabilizing circuit to become a 5V DC power supply, the 5V DC power supply obtains positive high voltage through the boost circuit, and the 5V DC power supply generates a 5V isolated DC power supply through the power isolation module. The anode of the positive high voltage is connected to the ground of the 5V isolated DC power supply to convert the positive high voltage into negative high voltage. The 5V isolated DC power supply powers the detector output signal processing circuit. In the detector output signal processing circuit part, the detector signal is first processed by the analog signal processing module, and then the processed signal is transmitted to the digital signal processing module for final processing. The power supply of the digital signal processing module and the 5V DC power supply in the power supply circuit module are connected to the digital isolator to ensure communication between the digital signal processing module and the outside.

[0115] The specific steps are as follows: Step 1: This part converts the external power supply into the power supply required by the system. First, the external power supply Vin_PRT is converted into 5V_HV, U1 converts 5V_HV into a 3.3V DC voltage source, and the transformer T1 uses the DC / DC converter U14 to boost the voltage obtained by 5V_HV and the variable voltage difference between 5V_HV, and then passes through the voltage doubler rectifier circuit composed of capacitors and diodes and the filter circuit composed of capacitors and resistors to obtain the corresponding positive high voltage. 5V_HV is connected to the power isolation module J10 to generate a DC power supply 5V_MCU isolated from it. Finally, the anode of the positive high voltage is connected to the ground of 5V_MCU to form a negative high voltage, and then connected to the probe of the detector. The voltage source 5V_HV and 3.3V are grounded with the external power supply Vin_PRT, but isolated from 5V_MCU. The model of T1 is Z2w, the model of U14 is LT3580, the model of J10 is PDSE1-S5-S5, and the model of U1 is MCP1700-3002E. Step 2: 5V_MCU is stepped down by U12 to obtain the power supply VDDA. The model of U12 is BU33TD3WG. PeakClear is the signal sent by the chip to control the switch of the MOS tube, PMT_signal is the signal sent by the detector, and ADC_COMP_IN is the port connected to the chip analog-to-digital converter. The model of MOS tube Q1 is DMG2307L or DMG1013T.

[0116] Step 3: Use U11 to convert 5V_MCU to 3V3_MCU. . U4 is a digital isolation module. Since the power supply 5V_MCU of the chip is isolated from the outside, and the ground of 5V_MCU is connected to the anode of the positive high voltage, the digital isolation module can achieve electrical insulation between the system and external devices, and provide a safe channel for the chip to communicate with the outside world. The other parts are the components of the normal operation of the chip. ADC_COMP_IN is connected to the corresponding pin of the chip. The chip digitizes the analog signal, then processes the digital signal for identification, and finally transmits the identified signal to the host computer. Among them, the model of U2 is STM32G431, the model of U4 is ADuM1201AR, and the model of U11 is MCP1700-3002E. First Figure 5 The circuit in the system provides voltage for the system. The negative high voltage provides the operating voltage for the photomultiplier tube (PMT) in the system, and then Figure 7 After receiving the current pulse signal from the detector, the circuit converts the current pulse signal into a voltage difference signal by utilizing the switching characteristics of the MOS tube and the charging and discharging characteristics of the capacitor and amplifying the voltage difference signal through the amplifier.

[0117] The beneficial effects of the present invention are as follows:

[0118] Convert the positive high voltage into negative high voltage, and use digital isolators to eliminate the impact of the ground-connected positive high voltage DC power supply of the isolated 5V DC power supply on the circuit. This method uses power isolators to provide a new way to generate negative voltage for nuclear electronic circuits;

[0119] The analog signal processing method in this system converts the negative current pulse signal output by the detector into a voltage difference signal through a MOSFET transistor, avoiding ballistic loss, filtering and shaping the pulse signal, baseline recovery and other complex processing processes, and reducing the influence of electronic components in the analog circuit on the signal;

[0120] The present invention can effectively identify signals. The signal processing part of the system adopts a method combining analog signal processing technology with digital signal processing technology, simplifies the hardware circuit, reduces power, solves the noise and other problems caused by the hardware circuit, and improves the stability and anti-interference of the system.

[0121] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0122] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A radiation detector signal processing system based on MOS tube, the radiation detector comprising: Photomultiplier tube, power supply generation module, characterized in that the signal processing system includes: an analog signal processing module and a digital signal acquisition processing module; The photomultiplier tube comprises: a cathode K of the photomultiplier tube, an anode P of the photomultiplier tube, a multiplier electrode and a voltage divider circuit; The power supply generation module includes: an external power supply, a first voltage stabilizer, a second voltage stabilizer, a third voltage stabilizer, a fourth voltage stabilizer, a boost circuit, a shaping filter circuit, and a power isolation module; The external power source is connected to the first voltage stabilizer, so that the external power source is stabilized by the first voltage stabilizer to obtain a first DC voltage source; The first DC voltage source is connected to the second voltage stabilizer; the first DC voltage source is stabilized by the second voltage stabilizer to obtain a second DC voltage source; The first DC voltage source is connected to the power isolation module and is used to generate a first isolated DC voltage source; The first isolated DC voltage source is connected to the third voltage stabilizer, so that the first isolated DC voltage source is stabilized by the third voltage stabilizer to obtain a second module power supply; The first isolated DC voltage source is connected to the fourth voltage stabilizer, so that the first isolated DC voltage source is stabilized by the fourth voltage stabilizer to obtain a third module power supply; The first DC voltage source generates a positive high voltage power supply through the boost circuit and the shaping filter circuit; An anode of the positive high-voltage power source generated by the first DC voltage source is connected to the ground of the first isolated DC voltage source, and is used to convert the positive high-voltage power source into a negative high-voltage power source; The negative high voltage is connected to the last stage DY8 of the dynode of the photomultiplier tube, and is used to provide the voltage required by the dynode. The ground of the first DC voltage source is connected to the cathode K of the photomultiplier tube. The power isolation module includes: a power isolator; The power isolator is used to isolate the ground of the 5V DC power supply and the ground of the 5V isolated DC power supply; The analog signal processing module includes: a MOS tube, a first capacitor and an amplifier; Pin 2 of the MOS tube Q1 is connected to the anode of the power supply VDDA, pin 3 of the MOS tube Q1 is connected to the amplifier, pins 2 and 3 of the MOS tube Q1 are connected in parallel to the first capacitor, and the negative current pulse signal PMT_signal output by the photomultiplier tube is connected to pin 3 of Q1; The first capacitor is charged by the MOS tube Q1, and the different negative current pulse signals PMT_signal pass through the first capacitor, the first capacitor is discharged, the voltage drop is obtained to obtain a voltage difference signal, and the voltage difference is amplified to obtain an amplified voltage difference; The digital signal acquisition and processing module includes: a chip and a digital isolator; The chip is connected to the amplifier and the digital isolator respectively, and is used for collecting voltage difference analog signals, converting the analog signals into digital signals, processing the digital signals, and finally transmitting data.

2. The radiation detector signal processing system based on MOS tube according to claim 1, characterized in that: The chip includes a PeakClear output signal; The PeakClear output signal is connected to pin No. 13 of the chip, and the PeakClear output signal is connected to pin No. 1 of the MOS tube Q1 to control the conduction of the MOS tube Q1 to charge the first capacitor.

3. The radiation detector signal processing system based on MOS tube according to claim 1, characterized in that: Pins 2 and 3 of the digital isolator are connected to pins 20 and 19 of the chip respectively; Pin 8 of the digital isolator is connected to the first DC voltage source, pin 1 of the digital isolator is connected to the power supply of the third module, pin 5 of the digital isolator is connected to the ground of the first DC voltage source, and pin 4 of the digital isolator is connected to the ground of the first isolated DC voltage source. The digital isolator is used to isolate the ground of the first DC voltage source from the ground of the first isolated DC voltage source to facilitate stable data transmission.

4. The radiation detector signal processing system based on MOS tube according to claim 1, characterized in that: The boost circuit comprises: a transformer and a converter; The transformer and the converter are respectively connected to the first DC voltage source and are used to convert and boost the first DC voltage source.

5. The radiation detector signal processing system based on MOS tube according to claim 1, characterized in that: include: The second module power supply is used to supply power to the analog signal processing module; The third module power supply is a 3V3 power supply, which is used to supply power to the digital signal acquisition and processing module.

6. A radiation detector signal processing method based on MOS tube, applied to the system according to any one of claims 1 to 5, characterized in that: include: Using an external power source to obtain a first DC voltage source through voltage stabilization by a first voltage stabilizer; The first DC voltage source is stabilized by a second voltage stabilizer to obtain a second DC voltage source; Using the first DC voltage source and the power isolation module to generate a first isolated DC voltage source; The first isolated DC voltage source is used to obtain a second module power supply through voltage stabilization by a third voltage stabilizer; The third module power supply is obtained by utilizing the first isolated DC voltage source and stabilizing it through a fourth voltage stabilizer; Using a first DC voltage source to generate a positive high voltage power supply via a boost circuit and a shaping filter circuit; Connecting the anode of the positive high-voltage power source generated by the first DC voltage source to the ground of the first isolated DC voltage source to convert the positive high-voltage power source into a negative high-voltage power source; Use negative high voltage to connect the last stage DY8 of the dynode of the photomultiplier tube to provide the voltage required by the dynode; Use a power isolator to isolate the ground of the 5V DC power supply and the ground of the 5V isolated DC power supply; The first capacitor is charged by the MOS tube Q1, and different negative electric pulse signals pass through the first capacitor, the first capacitor is discharged, and the voltage drop is obtained to obtain a voltage difference signal, and the voltage difference is amplified to obtain an amplified voltage difference; The chip is used with an amplifier and a digital isolator to collect voltage difference analog signals, convert the analog signals into digital signals and process them, and finally transmit data.

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