CN111948698B - Satellite-borne intermediate-energy proton detector - Google Patents

Abstract

The invention discloses a medium energy proton detector, which comprises a probe and an electronics part, wherein the probe is used for outputting charge pulses of medium energy protons to the electronics part; the detection energy range of the intermediate energy proton is 20 KeV-5 MeV; and the electronic part is used for processing the received charge pulse and obtaining the energy of the intermediate energy protons by analyzing the amplitude of the pulse signal. The detector can realize that the detection range of the medium-energy protons is as low as 20KeV, the detector is upwards connected with the detection energy section of the high-energy protons, and the detector is downwards partially overlapped with the detection energy section of the plasma, so that full-spectrum seamless measurement, fine energy spectrum and high-direction resolution measurement can be realized, the energy transfer and distribution state change of space particles can be monitored, the detector has important significance for researching magnetic tail ground energy transportation and global radiation environment modeling, and meanwhile, the detector can early warn solar proton events.

Description

A spaceborne medium-energy proton detector

technical field

The invention relates to the field of aerospace, in particular to a space-borne medium-energy proton detector.

Background technique

Medium-energy proton detectors (energy range 20KeV～5MeV) are easily polluted by other particles and sunlight due to the extremely low deposition energy of the measured particles in the sensor (the lower limit of deposition energy is 10KeV), and it is difficult to realize them. on board.

The current similar loads are mainly high-energy particle detectors, including high-energy proton, electron, and heavy ion detectors. , the current particle radiation detector is generally at 10 ⁵ /s, which is very easy to reach saturation in space environmental events such as magnetic storms and solar proton events.

There are many reasons that restrict the development of this type of load to low-energy detection. In addition to the selection of sensors and front-end circuits, it also includes the design of noise suppression circuits, signal shaping circuits, high-voltage circuits, and anti-particle interference and anti-light pollution designs. , can not meet the design requirements of spaceborne.

Contents of the invention

The purpose of the present invention is to overcome the above-mentioned technical defects, and to design a medium-energy proton detector, which can be used on a satellite.

To achieve the above object, the present invention discloses a medium-energy proton detector, which includes a probe and an electronic part,

The probe is used to output the charge pulse of the medium-energy proton to the electronics part after the front-end signal processing; the detection energy range of the medium-energy proton is 20KeV～5MeV;

The electronics part is used to process the received charge pulse, and obtain the energy of the intermediate-energy proton by analyzing the amplitude of the pulse signal.

As an improvement of the above-mentioned device, the probe includes a probe housing and built-in three independent detection units and a front-end processing module, each detection unit is a "small hole imaging" structure, including a collimator, a deflection magnet, anti-scatter device and six-chip sensor;

The collimator is arranged on the outside of the probe housing, and is used to allow charged particles to enter the housing;

The deflection magnet is used to deflect the medium-energy electrons so that they cannot be incident on the sensor,

The anti-scattering device is used to reduce the amount of charged particles entering the sensor through reflection;

The six sensors are divided into three groups, each group has two sensors at the top and bottom, to achieve a detection field of view of 20°×20°, and the field of view of each detection unit is 20°×60°, and the detection field of view of the three detection units is spliced Finally, a detection range of 20°×180° is realized;

The front-end processing module includes 18 road pre-amplifier circuits and a common circuit board; the 18-way pre-amplifier circuits are connected to 18 sensors respectively, and 18 road shaping and main amplifier circuits are set on the common circuit board; the pre-amplifier circuits are used for The charge signal generated after the protons are incident on the sensor is converted into a voltage signal; the shaping and main amplifier circuit is used for shaping and amplifying the voltage signal.

As an improvement of the above-mentioned device, the sensor is an ion-implanted semiconductor sensor; in each group of sensors, one sensor is used as a pulse amplitude analyzer for the division of energy levels, and the other is used as an anti-coincidence detector to eliminate high-energy Interference with protons and energetic electrons.

As an improvement of the above-mentioned device, the electronics part includes: an electronics box and five built-in circuit boards, and the five circuit boards include: a first analog board, a second analog board, a power board, a digital board and motherboard;

The first analog board is used to set 12 peak protection circuits and 12 trigger circuits connected to 2 detection units; the second simulation board is used to set 6 peak protection circuits and 6 trigger circuits connected to 1 detection unit. One trigger circuit and one high voltage circuit;

The peak protection circuit is used to form a pulse height signal that can be collected from the voltage pulse signal output by the forming and main amplifier circuit; the trigger circuit is used to output a trigger signal according to when the signal amplitude exceeds a set threshold;

The power supply board is used to set the power supply circuit, convert the primary power supply provided by the satellite, and provide working voltage to each circuit;

The digital board is provided with 6 A/D collectors, FPGA, memory and 422 interface circuits; one detection unit corresponds to two A/D collectors; each A/D collector receives the trigger signal output by the trigger circuit , collect the pulse height signal output by the peak protection circuit corresponding to the trigger circuit; the FPGA is used to analyze the amplitude of the pulse height output by the 6 A/D collectors, determine the energy and energy level of the incident particle, and use It is used to package the data to form a complete data package, store it in the memory, and send it to the satellite platform through the 422 interface;

The motherboard is used to set the connectors corresponding to the other four circuit boards, and transmit signals between the circuit boards.

As an improvement of the above device, the probe housing and the electronics box are separated by a polyimide gasket with a thickness of 1mm, the probe housing is connected to the signal ground, and the electronics box is connected to the signal ground through a 5M ohm resistor.

As an improvement of the above-mentioned device, the electronic box is connected with external equipment through a 38-core connector, and performs power supply input and data output to the detector.

As an improvement of the above-mentioned device, a 26-core and a 38-core connector are reserved in the electronics box for connecting another probe in parallel through a cable.

The electronics box is connected with external equipment through a 38-core connector, and supplies power input and data output to the detector; the electronics box reserves a 26-core and a 38-core connector for connecting another probe in parallel through a cable .

The advantages of the present invention are:

1. The detector of the present invention realizes the energy lower limit measurement of 20KeV through electromagnetic compatibility design and circuit design;

2. The detector of the present invention realizes a counting rate of 10 ⁶ pieces/s through the design of the forming circuit;

3. The detector of the present invention effectively excludes protons and other particles outside the detection energy range, and is insensitive to optical signals;

4. The detector of the present invention adopts a combination of magnets, anti-scattering devices and sensors to achieve anti-particle interference;

5. The detector of the present invention can realize the detection range of medium-energy protons as low as 20KeV, connect upward with the detection energy range of high-energy protons, and partially overlap with the detection energy range of plasma downwards, and can realize seamless measurement of full-energy spectrum , fine energy spectrum, and high directional resolution measurement, so as to monitor the energy transfer and distribution state changes of space particles, which is of great significance for the study of geotropic energy transport in the magnetotail and the modeling of the global radiation environment. At the same time, it can provide early warning for solar proton events and current newspapers;

6. The medium-energy proton detectors of the present invention have been deployed on Fengyun-3 and No.4 satellites, as well as on aircraft such as the experimental cabin of my country's space station.

Description of drawings

Fig. 1 is a three-dimensional schematic diagram of a medium-energy proton detector of the present invention;

Fig. 2 is three views of the medium-energy proton detector of the present invention;

Fig. 3 is the schematic diagram of probe structure of the present invention;

Fig. 4 is a schematic block diagram of the detection unit of the medium-energy proton detector of the present invention;

Fig. 5 is the composition and connection relationship of the medium-energy proton detector of the present invention;

Fig. 6 is a block diagram of the electronic part of the medium-energy proton detector of the present invention;

Fig. 7 is a schematic diagram of key circuits of the medium-energy proton detector of the present invention.

Detailed ways

The technical solution of the present invention will be described in detail below in conjunction with the accompanying drawings.

1. Description of product indicators

Summary of energy proton detector indicators in Table 1

2. Composition and connection relationship

As shown in Fig. 1 and Fig. 2, the present invention provides a medium-energy proton detector, including a probe and an electronic part. The probe includes the probe housing and three independent detection units and their front-end signal processing circuits. The electronics part includes: the electronics box and five built-in circuit boards, which are used to process the output signals of the probe and are responsible for the external interface. Including data transmission and power input with external equipment.

The probe shell and the electronics box are separated by a polyimide gasket with a thickness of 1mm. The probe shell is connected to the signal ground, and the electronics box is connected to the signal ground through a 5M ohm resistor; the electronics box is connected to the external equipment through a 38-core connector. Connected to the machine for power input and data output; there is a 26-core and a 38-core connector in the electronics box, and another probe can be connected in parallel through the cable to achieve more directions of medium-energy proton detection.

As shown in Figure 3, each detection unit is a "small hole imaging" structure, including a collimator, a deflection magnet, an anti-scattering device, and six sensors; the collimator is set outside the probe housing for Charged particles enter the shell; the six sensors are divided into three groups, each group has two sensors above and below to achieve a detection field of view of 20°×20°, so the field of view of each detection unit is 20°×60°, three The detection field of view of the detection unit is spliced to achieve a detection range of 20°×180°.

The function of the deflection magnet is to eliminate the interference of the middle and low energy electrons on the measurement of the middle energy proton probe. For medium-energy protons and medium-energy electrons with the same energy, their energy loss in the silicon semiconductor sensor is the same, and they cannot be identified on the circuit. Therefore, a deflection magnet is used inside the instrument to deflect the medium-energy electrons, so that they cannot Incident into the silicon sensor, so as to achieve the purpose of eliminating interference.

The deflection magnet is a permanent magnetic magic ring structure, and the parameters are shown in Table 2:

Table 2: Magnet parameter table

parameter Inner diameter Outer diameter high field strength value 14mm 24mm 10mm 4000Gs

anti-scattering device to reduce the amount of charged particles entering the sensor by reflection;

The output signal of each detection unit enters the pre-amplification circuit, and the pre-amplification circuit converts it into a voltage signal and outputs it to the shaping circuit and the amplifying circuit. These circuits are arranged in the probe part, and the circuit of the detection unit is shown in Figure 4.

Ion-implanted semiconductor sensors have good energy resolution and are the mainstream sensors currently used. The specific indicators of the sensor are shown in Table 3. The sensor thickness is 300 μm. The area diameter of the sensor affects the geometric factor of the instrument, that is, the ability of the instrument to accept particles. The area of the sensor in the proton probe is 8×8mm.

Table 3: Sensor Characteristic Parameters

The sensors D1 and D2 of each group are connected to a separate amplifying circuit. The D1 sensor is used as a pulse amplitude analyzer for the division of energy levels, and D2 is used as an anti-coincidence detector to eliminate the interference of high-energy protons and high-energy electrons. The working mode of the sensor for D1·

Each sensor is connected to a set of electronic processing circuits, so there are 18 sets of electronic processing circuits in total. Electronics processing circuit includes pre-amplifier circuit, shaping and main amplifier circuit, peak protection circuit, power supply circuit, 6 A/D collectors, high-voltage circuit, FPGA, memory and 422 interface; as shown in Figure 5. One detection unit corresponds to two A/D collectors.

The electronics part of the intermediate-energy proton detector processes and collects the intermediate-energy particle signals output by the probe. The high voltage of the sensor is provided by the high voltage circuit. The basic process is to generate a charge signal after the medium-energy protons are incident on the sensor. The charge signal is converted into a voltage signal through the preamplifier circuit, forming and main amplifier circuit, and the signal is amplified at the same time, and then the voltage pulse The signal passes through the peak protection circuit to form a pulse height that can be collected, and the A/D collector collects the pulse height. The energy level to which the incident particles belong, and finally the data is packaged and processed by the FPGA to form a complete data package. The basic functions and data processing process of the electronics part are shown in Figure 6.

Electronics part includes: Electronics box and built-in five circuit boards, five circuit boards include: first analog board, second analog board, power board, digital board and motherboard;

The first analog board is used to set 12-way peak protection circuits and 12-way trigger circuits connected to 2 detection units; the second simulation board is used to set 6-way peak protection circuits and 6-way trigger circuits connected to 1 detection unit and One high voltage circuit;

The peak protection circuit is used to form the voltage pulse signal output by the forming and main amplifier circuit into a pulse height signal that can be collected; the trigger circuit is used to output a trigger signal when the signal amplitude exceeds the set threshold;

The power board is used to set the power circuit, convert the primary power provided by the satellite, and provide working voltage for each circuit;

The digital board is equipped with 6 A/D collectors, FPGA, memory and 422 interface circuits; one detection unit corresponds to two A/D collectors; after each A/D collector receives the trigger signal output by the trigger circuit, it The pulse height signal output by the peak protection circuit corresponding to the trigger circuit is collected; the FPGA is used to analyze the amplitude of the pulse height output by the 6 A/D collectors, determine the energy and energy level of the incident particles, and is also used to analyze the data. Packing and processing to form a complete data package, store it in the memory, and send it to the satellite platform through the 422 interface;

The motherboard is used to set the connectors corresponding to the other 4 circuit boards, and transmit signals between the circuit boards.

The use of main components of the medium-energy proton detector is shown in Table 4:

Table 4: List of main electronic components

serial number Component name Specifications 1 charge sensitive preamplifier A250F 2 filter shaping OP467AY 3 main amplifier OP467AY 4 Peak protection circuit MLT9821 5 Transformer (high voltage) HYL6267 6 trigger circuit AD8561 7 ADC acquisition B9243 8 power module SVSA2812D 9 power module SVSA285R2S 10 FPGA A54SX72A-CQ208B 11 storage 3DSR32M32VS8504 12 422 interface chip AM26C31MJB 13 422 interface chip AM26C32MJB

Front-end electronics are key to achieving detection metrics:

The signal of the detection unit (collimator + magnet + anti-scattering device + sensor + pre-amplifier circuit) is output to a common circuit board for shaping and amplification. The front-end circuit form is shown in Figure 7:

In the figure: Cf＝0.25pF, Rf＝1GΩ, R1＝R3＝R4＝R5＝1KΩ, R2＝20KΩ, C1＝C3＝200pF, C2＝10pF, C4＝100pF, τ＝0.2us

When t=2.4τ=0.48us, the signal reaches the maximum value, and the amplification factor of the front-end circuit:

A=1108mV/MeV

For a deposition energy of 10KeV, the signal output is 11mV, which can realize the measurement of the lower limit of energy. At this time, the signal is close to Gaussian waveform, the time period of the whole signal is 1us, and the counting rate of 10 ⁶ /s can be realized.

3. The detection process of the detector of the present invention is:

When the charged particles are injected into the three detection units through the three collimators, they first pass through the magnetic field of the permanent magnetic ring, and the low- and medium-energy electrons deviate from the sensor, and then deposit energy in each group of sensors to generate corresponding electron holes in the form of ionization. Yes, these electron-hole pairs are brought together to the output terminal under the action of a high-voltage electric field and generate a charge pulse. The charge pulse height is proportional to the energy deposited by the particles in the semiconductor detector. By analyzing the amplitude of the pulse signal generated by the energy deposited by the incident particles in each sensor, the type and energy of the incident particles can be judged.

The medium-energy proton detector of the present invention solves the following technical problems:

For the energy lower limit problem, the existing problems in the prior art are mainly insufficient electromagnetic compatibility design, and the background noise of the detector has reached more than 50KeV. 1. Starting from several aspects of high-voltage circuit design, the background noise of the detector is controlled at about 5KeV.

For the counting rate problem, previous similar detectors mainly use a shaping circuit with a long shaping time constant (generally greater than 2us in order to suppress noise) and a reset circuit with a fixed reset time (3us), so that the counting rate of the detector does not exceed 10 ⁵ A/s. The present invention redesigns the forming circuit, so that the forming time of the forming circuit is 0.5us, and at the same time, the reset signal is provided by the digital circuit, that is, the signal is reset by the FPGA immediately after the AD collection is completed, so that the processing time of the whole signal is 1us, like this Can make the counting rate increased to 10 ⁶ /s.

For the anti-particle interference problem, the low- and middle-energy electrons entering the detection field of view are deviated from the sensor by using a deflection magnet; at the same time, the anti-coincidence sensor is used to remove high-energy electrons and other types of particles that cannot be deviated.

For the problem of light pollution, by designing an appropriate sensor coating thickness, it can not only remove light pollution, but also minimize the energy loss in the coating.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than limit them. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that modifications or equivalent replacements to the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention, and all of them should be included in the scope of the present invention. within the scope of the claims.

Claims (5)

1. A medium-energy proton detector, characterized in that, the detector comprises a probe and an electronics part, The probe is used to output the charge pulse of the medium-energy proton to the electronics part after the front-end signal processing; the detection energy range of the medium-energy proton is 20KeV～5MeV; The electronic part is used to process the received charge pulse, and obtain the energy of the intermediate-energy proton by analyzing the amplitude of the pulse signal; The probe includes a probe housing and built-in three independent detection units and a front-end processing module. Each detection unit is a "small hole imaging" structure, including a collimator, a deflection magnet, an anti-scattering device and six sensor; The collimator is arranged on the outside of the probe housing, and is used to allow charged particles to enter the housing; The deflection magnet is used to deflect the medium-energy electrons so that they cannot be incident on the sensor, The anti-scattering device is used to reduce the amount of charged particles entering the sensor through reflection; The six sensors are divided into three groups, each group has two sensors at the top and bottom, to achieve a detection field of view of 20°×20°, and the field of view of each detection unit is 20°×60°, and the detection field of view of the three detection units is spliced Finally, a detection range of 20°×180° is realized; The front-end processing module includes 18 road pre-amplifier circuits and a common circuit board; the 18-way pre-amplifier circuits are connected to 18 sensors respectively, and 18 road shaping and main amplifier circuits are set on the common circuit board; the pre-amplifier circuits are used for The charge signal generated after the protons are incident on the sensor is converted into a voltage signal; the shaping and main amplifier circuit is used to shape and amplify the voltage signal; The electronics part includes: an electronics box and five built-in circuit boards, and the five circuit boards include: a first analog board, a second analog board, a power board, a digital board and a motherboard; The first analog board is used to set 12 peak protection circuits and 12 trigger circuits connected to 2 detection units; the second simulation board is used to set 6 peak protection circuits and 6 trigger circuits connected to 1 detection unit. One trigger circuit and one high voltage circuit; The peak protection circuit is used to form a pulse height signal that can be collected from the voltage pulse signal output by the forming and main amplifier circuit; the trigger circuit is used to output a trigger signal according to when the signal amplitude exceeds a set threshold; The power supply board is used to set the power supply circuit, convert the primary power supply provided by the satellite, and provide working voltage to each circuit; The digital board is provided with 6 A/D collectors, FPGA, memory and 422 interface circuits; one detection unit corresponds to two A/D collectors; each A/D collector receives the trigger signal output by the trigger circuit , collect the pulse height signal output by the peak protection circuit corresponding to the trigger circuit; the FPGA is used to analyze the amplitude of the pulse height output by the 6 A/D collectors, determine the energy and energy level of the incident particle, and use It is used to package the data to form a complete data package, store it in the memory, and send it to the satellite platform through the 422 interface; The motherboard is used to set the connectors corresponding to the other four circuit boards, and transmit signals between the circuit boards. 2. The medium-energy proton detector according to claim 1, characterized in that, the sensor is an ion-implanted semiconductor sensor; in each group of sensors, a slice of sensor is used as a pulse amplitude analyzer for the division of energy levels, and another One piece is used as an anti-coincidence detector to eliminate the interference of high-energy protons and high-energy electrons. 3. The medium-energy proton detector according to claim 1, characterized in that, the probe housing and the electronics box are separated by a polyimide gasket with a thickness of 1mm, the probe housing is connected to the signal ground, and the electronics box is connected to the ground. The school box is connected to the signal ground through a 5M ohm resistor. 4. The medium-energy proton detector according to claim 3, characterized in that the electronics box is connected to external equipment through a 38-core connector to provide power input and data output to the detector. 5. The medium-energy proton detector according to claim 3, wherein a 26-core and a 38-core connector are reserved in the electronics box for parallel connection of another probe through a cable.

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