CN115015652A - Method and system for improving electron current detection performance - Google Patents
Method and system for improving electron current detection performance Download PDFInfo
- Publication number
- CN115015652A CN115015652A CN202210631212.4A CN202210631212A CN115015652A CN 115015652 A CN115015652 A CN 115015652A CN 202210631212 A CN202210631212 A CN 202210631212A CN 115015652 A CN115015652 A CN 115015652A
- Authority
- CN
- China
- Prior art keywords
- current
- sampling
- channel
- signal
- avr
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R29/00—Arrangements for measuring or indicating electric quantities not covered by groups G01R19/00 - G01R27/00
- G01R29/24—Arrangements for measuring quantities of charge
Abstract
The invention discloses a method for improving the detection performance of electron current, which comprises the following steps: step 1, multi-channel simultaneous sampling detection beam signals; step 2, filtering the beam current signal by using a triaxial cable and a differential operational amplifier; step 3, improving the beam signal quality; step 4, calculating the charge quantity information of the beam current signal; the step 3 of improving the beam signal quality comprises a multi-channel cooperative control method, a sampling wild value elimination method based on threshold judgment, a sliding window filtering method and a dynamic self-checking calibration method; in the step 4, the calculation of the electric charge amount of the beam current signal is completed through an integrating circuit; the invention improves the quality of the beam flow signal by combining software and hardware, and the software mode is a sampling wild value elimination method, a sliding window filtering method, a multi-channel cooperative control method and a dynamic self-checking calibration method.
Description
Technical Field
The invention relates to the field of detection, in particular to a method and a system for improving the detection performance of electron current.
Background
The beam quality is a symbol of the performance of the accelerator, along with the development of the accelerator technology, the demand of high-quality beam clusters in the field of the accelerator is obviously increased, and an advanced beam diagnosis method is an important means for improving the beam cluster quality. The charge quantity and the beam intensity of the beam are important parameter indexes of the accelerator physics, and the integral value of the beam intensity is the charge quantity of the beam group.
The size and the stability degree of the beam group charge quantity are important characteristics of the high-quality beam, and the high-quality beam reflects the stability of a microwave system and a laser system and the emittance performance of the beam.
Therefore, measuring and detecting the amount of charge is an important task in beam diagnostic technology.
The beam measuring technology relates to various disciplines of precision machinery, fast and slow electronics, optics, microwaves, vacuum, accelerator physics and the like. Modern accelerators such as fourth generation light sources, international linear colliders, high current proton accelerators and the like develop towards the directions of low emittance, short beam length, high current and the like, and the high requirements on the beam measurement technology and the progress depending on modern industry and science and technology promote the rapid development of the beam measurement technology, particularly the application and the rapid development of the laser technology, the broadband high-frequency fast electronics technology, the non-blocking detection technology and various feedback technologies in the field of beam measurement.
In nuclear physics experimental measurement, the interaction between particles and substances is finally converted into measurable physical quantities, such as light, charge, current and the like, by a detector.
In a commonly used accelerator beam diagnostic device, because a probe interacts with beam particles in a sampling process and an electron blocking process plays a main role, signals output by most devices are multipath weak current signals, the amplitudes of the signals are usually nA and pA, the signals are very easily interfered by the outside, and the measurement is not accurate enough, so the measurement difficulty is very high.
Disclosure of Invention
The invention aims to: a method and system for improving electron current detection performance are provided to solve the above problems in the prior art.
The technical scheme is as follows: a method of improving electron flow detection performance, comprising:
step 1, multi-channel simultaneous sampling detection beam signals;
step 2, filtering the beam current signal by using a three-coaxial cable and a differential operational amplifier;
step 3, improving the beam signal quality;
step 4, calculating the charge quantity information of the beam current signal;
the step 3 of improving the beam signal quality comprises a multi-channel cooperative control method, a sampling wild value elimination method based on threshold judgment, a sliding window filtering method and a dynamic self-checking calibration method;
in the step 4, the calculation of the electric charge amount of the beam current signal is completed through an integrating circuit;
for the integration circuit, the relationship between the output voltage U and the charge amount Q is
Q＝UC
The integrated charge Q of the current i (t) over time over a period of time is:
in the formula, C is an integration capacitor, the amount of charge collected in the integration time can be measured by measuring the magnitude of the integration voltage through the ADC, dt represents the integration of higher mathematics to time, and the average current i in the period is:
i＝Q/(t 1 -t 2 )
the measuring range of the weak current preamplifier is divided into 1nA, 10nA, 100nA, 1 muA, 10 muA and 100 muA;
6 ranges, and output voltage of 0-10V corresponds to each range.
In practice, the current-to-voltage converter (IVC) is an impedance transformer that converts a weak current signal into a voltage signal, and has a high input impedance and a low output impedance.
Because the present application is the detection and processing of weak signal multi-channel signals.
How to reduce interference and noise and ensure the accuracy and precision of measurement is very difficult, so a sampling wild value rejection method, a sliding window filtering method, a multi-channel cooperative control method and a dynamic self-checking calibration method are designed to ensure the accuracy of measurement.
In the signal transmission process, the unshielded cable has an antenna effect, so that not only can signals be radiated to the outside, but also the interference of external signals is easily received, the electromagnetic interference of normal signals is easily caused, and the problems of signal distortion, noise increase and the like are caused.
The coaxial cable adopts structures such as a metal outer conductor and the like to enhance the shielding performance of the cable.
In consideration of the detection of weak signals corresponding to the present invention, it is necessary to consider selecting a coaxial cable with good enough shielding performance as much as possible and control the transmission impedance of the cable as much as possible (the coaxial cable has excellent impedance control performance).
The tri-coaxial cable is provided with an additional shielding layer, and the shielding protection effect can realize the shielding effectiveness better than that of the common coaxial cable.
The radio frequency triaxial connector is used for connecting a triaxial cable, has higher shielding performance compared with a common shielding connector, and can be used in occasions with high shielding requirements for transmission of weak signals.
The noise introduced by the system is thus greatly reduced.
The invention improves the beam signal quality by combining software and hardware, wherein the hardware mode is to use multi-channel simultaneous sampling to detect beam signals, match with a triaxial cable to transmit signals, use an operational amplifier in a differential mode to suppress environmental noise and remove common mode interference of a system, and filter by an RC filter consisting of a resistor and a capacitor. And the software mode is used for finishing the work of improving the quality of the beam current signals by a sampling wild value elimination method, a sliding window filtering method, a multi-channel cooperative control method and a dynamic self-checking calibration method.
In a further embodiment, the multi-channel cooperative control method includes:
based on a multi-channel simultaneous sampling technology, an AD circuit with synchronous trigger sampling capability is designed and used, and data are subjected to cooperative processing by utilizing multi-channel acquired data;
because the beam current passes through each beam current observation channel in sequence in the beam current channel, and the change of the beam current among the channels is small, the beam current signals of each channel are positioned at different positions of the beam current, and the waveform has strong correlation;
in order to reduce noise, the switching time of the integrating circuit is matched as much as possible, and the switching time needs to be dynamically adjusted according to different beams;
let the sampling signal of the ith channel be S i (k)；
The method comprises the following steps: correlating the received signal of the ith channel with the received signal of the 1 st channel;
step two: obtaining a correlation result R i (n) maximum value R max ；
Step three: maximum value R is judged max Whether greater than a correlation threshold;
if the value is larger than the preset value, the next step is carried out;
otherwise, returning to the first step;
step four: record R i Maximum value R in (n) max Is in the position N, i.e. R i (N)＝R max If N is the number of delayed sampling points of the current channel relative to the first channel;
step five: calculating delay time to be N x T, wherein T is ADC sampling period;
step six: whether the current delay time and the last delay time are less than T;
when the current channel is smaller than T, the delay adjustment processing of the integral switch of the current channel is finished;
otherwise, adjusting the delay time and returning to the first step;
and the synchronism of the sampled data is ensured through a synchronous triggering mechanism of the sampled data.
Considering that the local bias current of the system changes along with the conditions of temperature, pressure and the like, so that the output signal of the system also changes when no beam current passes through, the bias current of the integrating circuit, the offset voltage, the noise voltage and the like exist, and the influence of the leakage current of the integrating capacitor influences the read signal of the electronic current measuring circuit, so that the dynamic self-checking calibration method is designed to complete calibration.
In a further embodiment, the sample outlier culling method comprises:
let the sampling data of the signal of a single channel at each time be S i (k) The threshold reference window is M;
obtaining AVR for the first M data of the k sampling data left (k)；
Obtaining AVR for M data after the k-th sampling data right (k)；
The maximum threshold value of the current sampling point is Thr max (k)＝max{AVR left (k)，AVR right (k)}；
When the value S of the sampling point i (k) Greater than Thr max (k) If yes, the outlier is judged, the outlier is eliminated, and the outlier is updated to max { AVR } left (k)，AVR right (k)}；
The minimum threshold value of the current sampling point is Thr min (k)＝min{AVR left (k)，AVR right (k)}；
When the value S of the sampling point i (k) Less than Thr min (k) If yes, judging the outlier, eliminating the outlier, and updating the outlier to min { AVR } lef t(k)，AVR right (k)}。
In a further embodiment, the sliding window filtering method comprises:
the effective output signals are sorted and extracted by adopting a filtering algorithm to obtain the output signals after noise signals are removed, so that the precision and the accuracy of the method are effectively improved;
the sliding window filtering realizes the filtering processing of beam signals;
setting the width of a sliding window as K, setting K buffer areas for storing sampling data, and updating and storing the current sampling data S once according to a count value K (K is 0, 1, K-1) for reflecting the real-time change of a signal i (k) When the kth point is sampled currently, the new information of the current sampling period is used for covering the same position information of the previous sampling period, each time the new number is sampled, only one old data in the buffer area is covered, and other N-1 data are unchanged;
the recurrence formula of the sliding window average filter is:
wherein
Is the filtered result;
the average value is calculated by adopting a pointer moving method, so that high-efficiency calculation is realized, and the robustness of the calculation result is also ensured.
In a further embodiment, the dynamic self-test calibration method comprises the steps of matching a calibration circuit of a discharge resistor through a DAC chip;
the controller sets the output voltage U of the DAC cal ；
Through a discharge resistor R cal (such as 10G omega) and then calibrating the integrating circuit to control the output of the integrating voltage to be zero when no input signal exists, thereby eliminating the problem of local voltageThe influence of system noise such as bias current on the measurement result improves the measurement accuracy; calibration current I cal Comprises the following steps:
I cal ＝U cal /R cal
the circuit needs to be calibrated before the charge measurement starts, the electronics also needs to be calibrated daily in the actual working process,
in the calibration process, firstly, no other signal is connected into the integrating circuit, and then the integrating voltage U in delta t time is collected 0 Comprises the following steps: u shape 0 ＝ADC end -ADC start
In the formula, ADC end Integrating voltage collected by the ADC for a sampling end point;
ADC start integrating voltage collected for a sampling starting point;
only the calibration current needs to be guaranteed:
I cal ＝-U 0 /Δt
namely:
U cal ＝-R cal U 0 /Δt
the calibration process of the circuit can be completed.
A system for improving electron flow detection performance, comprising:
the device comprises an electronic flow measuring unit, a control unit and an interface unit;
the electron flow measuring unit consists of a plurality of electron flow detection groups, each electron flow detection group consists of four plugboard type electron flow detection channels, and each plugboard type electron flow detection channel comprises a detector and a transconductance amplifier;
the electron current detection group is communicated with the AD collector;
the transconductance amplifier is an operational amplifier in a differential mode.
The operational amplifier adopting the differential mode restrains the environmental noise and removes the common mode interference of the system.
The amplifier adopts a gating integration mode, and controls an integration time constant and discharge under the driving of a synchronous trigger signal.
In a further embodiment, the control unit comprises a control module, a range switching module, a display module and a network communication module;
the control module is communicated with the range switching module; the range switching module is communicated with the electron current detection channel;
the control module is communicated with the display module and the network communication module.
In a further embodiment, the control module comprises a controller, a display control board is arranged in the controller, and the range switching module comprises a range switching controller;
the display module comprises an LCD screen;
the AD collector is communicated with the controller;
the controller is also communicated with a plurality of comparators which are used for judging the magnitude of the input signal.
In a further embodiment, the interface unit is in communication with the controller, and the interface unit is configured to turn on the amplifying circuit, the comparing circuit, and the latch triggering circuit to form the final TTL interlock signal.
Aiming at the design requirements of multiple channels, the invention designs a 1-32 channel cuttable electron current detection combination and a multi-combination cooperative working mode.
Through the plug-in board type electron current detection channels, each plug-in board is provided with 4 electron current detection channels, and 8 channels can be combined into a 3U combination of 32 channels.
If the detection signal is more in demand, the detection signal can be integrated by combining a plurality of 3U combinations.
The software processing algorithm realizes the collaborative filtering of a plurality of combinations, and simultaneously performs data processing and collaborative data result display.
Has the advantages that: the invention discloses a method and a system for improving the detection performance of electron current, wherein the improvement of the beam current signal quality is completed in a soft and hard combination mode, and the software mode is a sampling wild value elimination method, a sliding window filtering method, a multi-channel cooperative control method and a dynamic self-checking calibration method; the hardware mode is to use a multi-channel to simultaneously sample and detect beam signals, match with a triaxial cable to transmit signals, use an operational amplifier in a differential mode to suppress environmental noise, remove common mode interference of a system, and simultaneously perform filtering through an RC filter consisting of a resistor and a capacitor to improve the quality of the beam signals, so that detected data are more accurate, and the detection difficulty is reduced.
Drawings
Fig. 1 is a schematic diagram of the system structure of the present invention.
FIG. 2 is a software process diagram of the present invention.
Figure 3 is a schematic of the multi-channel co-operation of the present invention.
FIG. 4 is a schematic diagram of the multi-channel co-processing of the present invention.
FIG. 5 is a schematic diagram of a gated integration circuit of the present invention.
Fig. 6 is a schematic view of a low noise 50 ohm triaxial cable according to the present invention.
Detailed Description
The present invention relates to a method and system for improving electron flow detection performance, which is explained in the following by means of specific embodiments.
A method of improving electron flow detection performance, comprising:
step 1, multi-channel simultaneous sampling detection beam signals;
step 2, filtering the beam current signal by using a triaxial cable and a differential operational amplifier;
step 3, improving the beam signal quality through a sampling wild value elimination method, a sliding window filtering method, a multi-channel cooperative control method and a dynamic self-checking calibration method based on threshold judgment;
in a further embodiment, the multi-channel cooperative control method includes:
based on a multi-channel simultaneous sampling technology, an AD circuit with synchronous trigger sampling capability is designed and used, and data are subjected to cooperative processing by utilizing multi-channel acquired data;
because the beam current passes through each beam current observation channel in sequence in the beam current channel, and the change of the beam current among the channels is small, the beam current signals of each channel are positioned at different positions of the beam current, and the waveforms of the beam current signals have strong correlation;
in order to reduce noise, the switching time of the integrating circuit is matched as much as possible, and the switching time needs to be dynamically adjusted according to different beams;
let the sampling signal of the ith channel be S i (k)；
The method comprises the following steps: correlating the received signal of the ith channel with the received signal of the 1 st channel;
step two: obtaining a correlation result R i (n) maximum value R max ；
Step three: maximum value R is judged max Whether greater than a correlation threshold;
if the value is larger than the preset value, the next step is carried out;
otherwise, returning to the first step;
step four: record R i Maximum value R in (n) max In the position N, i.e. R i (N)＝R max If N is the number of delayed sampling points of the current channel relative to the first channel;
step five: calculating delay time to be N x T, wherein T is ADC sampling period;
step six: whether the current delay time and the last delay time are less than T;
when the current channel is smaller than T, the delay adjustment processing of the integral switch of the current channel is finished;
otherwise, adjusting the delay time and returning to the first step;
and the synchronism of the sampled data is ensured through a synchronous triggering mechanism of the sampled data.
Considering that the local bias current of the system changes with the conditions of temperature, pressure and the like, so that the output signal of the system also changes when no beam current passes through, the bias current of the integrating circuit, the offset voltage, the noise voltage and the like exist, and the influence of the leakage current of the integrating capacitor can influence the read signal of the electronic current measuring circuit, so that a dynamic self-checking calibration method is designed to complete calibration.
In a further embodiment, the sample outlier culling method comprises:
let the sampling data of the signal of a single channel at each time be S i (k) The threshold reference window is M;
obtaining AVR for the first M data of the k sampling data left (k)；
Obtaining AVR for M data after the k-th sampling data right (k)；
The maximum threshold value of the current sampling point is Thr max (k)＝max{AVR left (k)，AVR right (k)}；
When the value S of the sampling point i (k) Greater than Thr max (k) If yes, the outlier is judged, the outlier is eliminated, and the outlier is updated to max { AVR } left (k)，AVR right (k)}；
The minimum threshold value of the current sampling point is Thr min (k)＝min{AVR left (k)，AVR right (k)}；
When the value S of the sampling point i (k) Is less than Thr min (k) If yes, judging the outlier, eliminating the outlier, and updating the outlier to min { AVR } left (k)，AVR right (k)}。
In a further embodiment, the sliding window filtering method comprises:
the effective output signals are sorted and extracted by adopting a filtering algorithm to obtain the output signals after noise signals are removed, so that the precision and the accuracy of the method are effectively improved;
the sliding window filtering realizes the filtering processing of beam signals;
setting the width of the sliding window as K, and setting K buffer areas for storing sampling data as real-time response signalsThe current sampling data S is updated and stored once by the count value K (K is 0, 1.., K-1) when changed i (k) When the kth point is sampled currently, the new information of the current sampling period is used for covering the same position information of the previous sampling period, each time the new number is sampled, only one old data in the buffer area is covered, and other N-1 data are unchanged;
the recurrence formula of the sliding window average filter is:
wherein
Is the filtered result;
the average value is calculated by adopting a method of moving the pointer, so that the high-efficiency calculation is realized, and the robustness of the calculation result is also ensured.
In a further embodiment, the dynamic self-test calibration method comprises the steps of matching a calibration circuit of a discharge resistor through a DAC chip;
the controller sets the output voltage U of the DAC cal ；
Through a discharge resistor R cal After (for example, 10G omega), the integral circuit is calibrated, and the integral voltage output is controlled to be zero when no input signal exists, so that the influence of system noise such as local bias current on the measurement result can be eliminated, and the measurement accuracy is improved; calibration current I cal Comprises the following steps:
I cal ＝U cal /R cal
the circuit needs to be calibrated before the charge measurement starts, the electronics also needs to be calibrated daily in the actual working process,
in the calibration process, firstly, no other signal is connected into the integrating circuit, and then, the integrating voltage U in delta t time is collected 0 Comprises the following steps: u shape 0 ＝ADC end -ADC start
In the formula, ADC end Integrating voltage collected by the ADC for a sampling end point;
ADC start integrating voltage collected for a sampling starting point;
only the calibration current needs to be guaranteed:
I cal ＝-U 0 /Δt
namely:
U cal ＝-R cal U 0 /Δt
the calibration process of the circuit can be completed.
Step 4, calculating the charge amount information of the beam current signal, and finishing the charge amount calculation of the beam current signal through an integrating circuit; for the integration circuit, the relationship between the output voltage U and the amount of charge Q is
Q＝UC
The integrated charge Q of the current i (t) over time is:
in the formula, C is an integrating capacitor, the amount of charge collected in the integrating time can be measured by measuring the magnitude of the integrating voltage through the ADC, and the average current i in the integrating time is:
i＝Q/(t 1 -t 2 )
the measuring range of the weak current preamplifier is divided into 1nA, 10nA, 100nA, 1 muA, 10 muA and 100 muA;
6 ranges, and output voltage of 0-10V corresponds to each range.
In practice, the current-to-voltage converter (IVC) is an impedance transformer that converts a weak current signal into a voltage signal, and has a high input impedance and a low output impedance.
Because the present application is the detection and processing of weak signal multi-channel signals.
How to reduce interference and noise and ensure the accuracy and precision of measurement is very difficult, so a sampling wild value rejection method, a sliding window filtering method, a multi-channel cooperative control method and a dynamic self-checking calibration method are designed to ensure the accuracy of measurement.
In the signal transmission process, the unshielded cable has an antenna effect, so that not only can signals be radiated to the outside, but also the interference of external signals is easily received, the electromagnetic interference of normal signals is easily caused, and the problems of signal distortion, noise increase and the like are caused.
The coaxial cable adopts structures such as a metal outer conductor and the like to enhance the shielding performance of the cable.
Considering that the invention is corresponding to the detection of weak signals, the coaxial cable with good shielding performance needs to be selected as much as possible, and the transmission impedance of the cable is controlled as well as much as possible (the coaxial cable has excellent impedance control performance).
The tri-coaxial cable is provided with an additional shielding layer, and the shielding protection effect can realize the shielding effectiveness better than that of the common coaxial cable.
The radio frequency triaxial connector is used for connecting a triaxial cable, has higher shielding performance compared with a common shielding connector, and can be used in occasions with high shielding requirements for transmission of weak signals.
The noise introduced by the system is thus greatly reduced.
The invention improves the beam signal quality by combining software and hardware, wherein the hardware mode is to use multi-channel simultaneous sampling to detect beam signals, match with a triaxial cable to transmit signals, use an operational amplifier in a differential mode to suppress environmental noise and remove common mode interference of a system, and filter by an RC filter consisting of a resistor and a capacitor. And the software mode is used for finishing the work of improving the quality of the beam current signal by a sampling wild value elimination method, a sliding window filtering method, a multi-channel cooperative control method and a dynamic self-checking calibration method.
A system for improving electron flow detection performance, comprising:
the device comprises an electronic flow measuring unit, a control unit and an interface unit;
the electron flow measuring unit consists of a plurality of electron flow detection groups, each electron flow detection group consists of four plugboard type electron flow detection channels, and each plugboard type electron flow detection channel comprises a detector and a transconductance amplifier;
the electron current detection group is communicated with the AD collector;
the transconductance amplifier is an operational amplifier in a differential mode.
The operational amplifier adopting the differential mode restrains the environmental noise and removes the common mode interference of the system.
The amplifier adopts a gate-control integration mode, and controls an integration time constant and discharge under the driving of a synchronous trigger signal.
In a further embodiment, the control unit comprises a control module, a range switching module, a display module and a network communication module;
the control module is communicated with the range switching module; the range switching module is communicated with the electron current detection channel;
the control module is communicated with the display module and the network communication module.
In a further embodiment, the control module comprises a controller, a display control board is arranged in the controller, and the range switching module comprises a range switching controller;
the display module comprises an LCD screen;
the AD collector is communicated with the controller;
the controller is also communicated with a plurality of comparators.
In a further embodiment, the interface unit is in communication with the controller, and the interface unit is configured to turn on the amplifying circuit, the comparing circuit, and the latch triggering circuit to form the final TTL interlock signal.
Aiming at the design requirements of multiple channels, the invention designs a 1-32 channel cuttable electron current detection combination and a multi-combination cooperative working mode.
Through the plug-in board type electron current detection channels, each plug-in board is provided with 4 electron current detection channels, and 8 channels can be combined into a 3U combination of 32 channels.
If the detection signal is more in demand, the detection signal can be integrated by combining a plurality of 3U combinations. The software processing algorithm realizes the collaborative filtering of a plurality of combinations, and simultaneously performs data processing and collaborative data result display.
Description of the working principle: the beam signals are simultaneously sampled and detected by multiple channels, and the beam signals are filtered by using a triaxial cable and an operational amplifier in a differential mode;
judging the size of an input signal by matching a multichannel cooperative control method with a comparator, designing and using an AD circuit with synchronous trigger sampling capability when simultaneously sampling in multiple channels, and performing cooperative processing on data by using the acquired data in the multiple channels;
because the beam current passes through each beam current observation channel in sequence in the beam current channel, and the change of the beam current among the channels is small, the beam current signals of each channel are positioned at different positions of the beam current, and the waveform has strong correlation;
in order to reduce noise, the switching time of the integrating circuit is matched as much as possible, and the switching time needs to be dynamically adjusted according to different beams;
let the sampling signal of the ith channel be S i (k)；
The method comprises the following steps: correlating the received signal of the ith channel with the received signal of the 1 st channel;
step two: obtaining a correlation result R i (n) maximum value R max ；
Step three: maximum value R is judged max Whether it is greater than a correlation threshold;
if the value is larger than the preset value, the next step is carried out;
otherwise, returning to the first step;
step four: record R i Maximum value R in (n) max Is in the position N, i.e. R i (N)＝R max If N is the number of delayed sampling points of the current channel relative to the first channel;
step five: calculating delay time to be N x T, wherein T is ADC sampling period;
step six: whether the current delay time and the last delay time are less than T;
when the current channel is smaller than T, the delay adjustment processing of the integral switch of the current channel is finished;
otherwise, adjusting the delay time and returning to the first step;
and the synchronism of the sampled data is ensured through a synchronous triggering mechanism of the sampled data.
Then improving the beam signal quality by a sampling wild value elimination method, a sliding window filtering method and a dynamic self-checking calibration method based on threshold judgment; finally, the over-integration circuit completes the calculation of the charge quantity information of the beam current signal;
when the sampling wild value is eliminated, the sampling data of the signal of a single channel at each moment is set as S i (k) The threshold reference window is M; obtaining AVR for the first M data of the k sampling data left (k) (ii) a Obtaining AVR for M data after the k-th sampling data riggght (k)；
The maximum threshold value of the current sampling point is Thr max (k)＝max{AVR left (k)，AVR right (k)}；
When the value S of the sampling point i (k) Greater than Thr max (k) If yes, judging the outlier, eliminating the outlier, and updating the outlier to max { AVR } left (k)，AVR right (k)}；
The minimum threshold value of the current sampling point is Thr min (k)＝min{AVR left (k)，AVR right (k)}；
When the value S of the sampling point i (k) Is less than Thr min (k) If yes, judging the outlier, eliminating the outlier, and updating the outlier to min { AVR } left (k)，AVR right (k)}。
In the sliding window filtering process, the effective output signals are sorted and extracted by adopting a filtering algorithm to obtain the output signals after noise signals are removed, so that the precision and the accuracy of the method are effectively improved;
the sliding window filtering realizes the filtering processing of beam signals;
setting the width of a sliding window as K, setting K buffer areas for storing sampling data, and updating and storing the current sampling data S once according to a count value K (K is 0, 1, K-1) for reflecting the real-time change of a signal i (k) That is, when the kth point is currently sampled, the new information of the current sampling period is used to cover the same position information of the previous sampling period, each time the new number is sampled, only one old data in the buffer is covered, and other new numbers are coveredN-1 data was unchanged; the average value is calculated by adopting a method of moving the pointer, so that the high-efficiency calculation is realized, and the robustness of the calculation result is also ensured.
Considering that the local bias current of the system changes along with the conditions of temperature, pressure and the like, so that the output signal of the system also changes when no beam current passes through, the bias current of the integrating circuit, the offset voltage, the noise voltage and the like exist, and the influence of the leakage current of the integrating capacitor influences the read signal of the electronic current measuring circuit, so that the dynamic self-checking calibration method is designed to complete calibration.
The dynamic self-checking calibration method comprises the steps that a DAC chip is matched with a calibration circuit of a discharge resistor;
the controller sets the output voltage U of the DAC cal ；
Through a discharge resistor R cal After (for example, 10G omega), the integral circuit is calibrated, and the integral voltage output is controlled to be zero when no input signal exists, so that the influence of system noise such as local bias current on the measurement result can be eliminated, and the measurement accuracy is improved;
the circuit needs to be calibrated before charge measurement begins, daily calibration of electronics is needed in the actual working process, no other signals are firstly ensured to be connected into the integrating circuit in the calibration process, and then the integrating voltage U in delta t time is collected 0 The calibration process of the circuit can be completed only by ensuring the calibration current.
Finally, the charge quantity information of the beam current signal is calculated, and the charge quantity calculation of the beam current signal is completed through an integrating circuit;
the magnitude of the integrated voltage is measured through the ADC, so that the charge quantity collected together in the integration time can be measured;
the measuring range of the weak current preamplifier is divided into 1nA, 10nA, 100nA, 1 muA, 10 muA and 100 muA;
6 ranges, and output voltage of 0-10V corresponds to each range.
In practice, the current-to-voltage converter (IVC) is an impedance transformer that converts a weak current signal into a voltage signal, and has a high input impedance and a low output impedance.
Because the present application is the detection and processing of weak signal multi-channel signals.
The preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, however, the present invention is not limited to the specific details of the embodiments, and various equivalent changes can be made to the technical solution of the present invention within the technical idea of the present invention, and these equivalent changes are within the protection scope of the present invention.
Claims (9)
1. A method of improving electron flow detection performance, comprising:
step 1, multi-channel simultaneous sampling detection beam signals;
step 2, filtering the beam current signal by using a triaxial cable and a differential operational amplifier;
step 3, improving the beam signal quality;
step 4, calculating the charge quantity information of the beam current signal;
the method is characterized in that the step 3 of improving the beam signal quality comprises a multi-channel cooperative control method, a sampling wild value elimination method based on threshold judgment, a sliding window filtering method and a dynamic self-checking calibration method;
in the step 4, the charge quantity calculation of the beam current signal is completed through an integrating circuit;
for the integration circuit, the relationship between the output voltage U and the amount of charge Q is
Q＝UC
The integrated charge Q of the current i (t) over time is:
in the formula, C is an integrating capacitor, the amount of charge collected in the integrating time can be measured by measuring the magnitude of the integrating voltage through the ADC, and the average current i in the integrating time is:
i＝Q/(t 1 -t 2 )
the measuring range of the weak current preamplifier is divided into 1nA, 10nA, 100nA, 1 muA, 10 muA and 100 muA;
6 ranges, and output voltage of 0-10V corresponds to each range.
2. A method of improving electron flow detection according to claim 1, wherein: the multichannel cooperative control method comprises the following steps:
based on a multi-channel simultaneous sampling technology, an AD circuit with synchronous trigger sampling capability is designed and used, and data are subjected to cooperative processing by utilizing multi-channel acquired data;
because the beam current passes through each beam current observation channel in sequence in the beam current channel, and the change of the beam current among the channels is small, the beam current signals of each channel are positioned at different positions of the beam current, and the waveform has strong correlation;
in order to reduce noise, the switching time of the integrating circuit is matched as much as possible, and the switching time needs to be dynamically adjusted according to different beams;
let the sampling signal of the ith channel be S i (k)；
The method comprises the following steps: correlating the received signal of the ith channel with the received signal of the 1 st channel;
step two: obtaining a correlation result R i (n) maximum value R max ；
Step three: maximum value R is judged max Whether it is greater than a correlation threshold;
if the value is larger than the preset value, the next step is carried out;
otherwise, returning to the first step;
step four: record R i Maximum value R in (n) max Is in the position N, i.e. R i (N)＝R max If N is the number of delayed sampling points of the current channel relative to the first channel;
step five: calculating delay time to be N x T, wherein T is ADC sampling period;
step six: whether the current delay time and the last delay time are less than T;
when the current channel is smaller than T, the delay adjustment processing of the integral switch of the current channel is finished;
otherwise, adjusting the delay time and returning to the first step;
and the synchronism of the sampled data is ensured through a synchronous triggering mechanism of the sampled data.
3. A method of improving electron flow detection according to claim 1, wherein: the sampling outlier rejection method comprises the following steps:
let the sampling data of the signal of a single channel at each time be S i (k) The threshold reference window is M;
obtaining AVR for the first M data of the k sampling data left (k)；
Obtaining AVR for M data after the k-th sampling data right (k)；
The maximum threshold value of the current sampling point is Thr max (k)＝max{AVR left (k)，AVR right (k)}；
When the value S of the sampling point i (k) Greater than Thr max (k) If yes, the outlier is judged, the outlier is eliminated, and the outlier is updated to max { AVR } left (k)，AVR right (k)}；
The minimum threshold value of the current sampling point is Thr min (k)＝min{AVR left (k)，AVR right (k)}；
When the value S of the sampling point i (k) Is less than Thr min (k) If yes, judging as outlier, eliminating, and updating to min { AVR } left (k)，AVR right (k)}。
4. A method of improving electron flow detection according to claim 1, wherein: the sliding window filtering method includes:
the effective output signals are sorted and extracted by adopting a filtering algorithm to obtain the output signals after noise signals are removed, so that the precision and the accuracy of the method are effectively improved;
the sliding window filtering realizes the filtering processing of beam signals;
setting the width of a sliding window as K, setting K buffer areas for storing sampling data, and updating and storing the current sampling data S once according to a count value K (K is 0, 1, K-1) for reflecting the real-time change of a signal i (k) When the kth point is sampled currently, the new information of the current sampling period is used for covering the same position information of the previous sampling period, each time the new number is sampled, only one old data in the buffer area is covered, and other N-1 data are unchanged;
the recurrence formula of the sliding window average filter is:
wherein
Is the filtered result;
the average value is calculated by adopting a method of moving the pointer, so that the high-efficiency calculation is realized, and the robustness of the calculation result is also ensured.
5. A method of improving electron flow detection according to claim 1, wherein: the dynamic self-checking calibration method comprises the steps that a DAC chip is matched with a calibration circuit of a discharge resistor;
the controller sets the output voltage U of the DAC cal ；
Through a discharge resistor R cal Then the integral circuit is calibrated to control the integral voltage output to be zero when no input signal exists, thereby eliminating the input signalThe measurement accuracy is improved due to the influence of system noise such as local bias current on the measurement result; calibration current I cal Comprises the following steps:
I cal ＝U cal /R cal
the circuit needs to be calibrated before the charge measurement starts, the electronics also needs to be calibrated daily in the actual working process,
in the calibration process, firstly, no other signal is connected into the integrating circuit, and then the integrating voltage U in delta t time is collected 0 Comprises the following steps: u shape 0 ＝ADC end -ADC start
In the formula, ADC end Integrating voltage collected by the ADC for a sampling end point;
ADC start integrating voltage collected for a sampling starting point;
only the calibration current needs to be guaranteed:
I cal ＝-U 0 /Δt
namely:
U cal ＝-R cal U 0 /Δt
the calibration process of the circuit can be completed.
6. A system for improving electron flow detection performance, comprising:
the device comprises an electronic flow measuring unit, a control unit and an interface unit;
the electron flow measuring unit consists of a plurality of electron flow detection groups, each electron flow detection group consists of four plugboard type electron flow detection channels, and each plugboard type electron flow detection channel comprises a detector and a transconductance amplifier;
the electron current detection group is communicated with the AD collector;
the transconductance amplifier is an operational amplifier in a differential mode.
7. The system of claim 6, wherein: the control unit comprises a control module, a range switching module, a display module and a network communication module;
the control module is communicated with the range switching module; the range switching module is communicated with the electron current detection channel;
the control module is communicated with the display module and the network communication module.
8. The system of claim 7, wherein: the control module comprises a controller, a display control board is arranged in the controller, and the range switching module comprises a range switching controller;
the display module comprises an LCD screen;
the AD collector is communicated with the controller;
the controller is also communicated with a plurality of comparators.
9. The system of claim 6, wherein: the interface unit is in communication with the controller.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210631212.4A CN115015652B (en) | 2022-06-06 | 2022-06-06 | Method and system for improving electron flow detection performance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210631212.4A CN115015652B (en) | 2022-06-06 | 2022-06-06 | Method and system for improving electron flow detection performance |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115015652A true CN115015652A (en) | 2022-09-06 |
| CN115015652B CN115015652B (en) | 2023-09-19 |
Family
ID=83073408
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210631212.4A Active CN115015652B (en) | 2022-06-06 | 2022-06-06 | Method and system for improving electron flow detection performance |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115015652B (en) |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH408198A (en) * | 1963-07-08 | 1966-02-28 | Kistler Instrumente Ag | Measuring amplifier for measuring electrical charges |
| US5128622A (en) * | 1990-02-06 | 1992-07-07 | Murata Mfg. Co., Ltd. | Multi-channel electrostatic sensor apparatus |
| JPH05264623A (en) * | 1992-03-17 | 1993-10-12 | Murata Mfg Co Ltd | Multichannel electrostatic sensor device |
| JPH062253U (en) * | 1992-06-10 | 1994-01-14 | 株式会社村田製作所 | Multi-channel electrostatic sensor device |
| CN203432677U (en) * | 2013-07-26 | 2014-02-12 | 浙江大学 | Dynamic calibration device of eddy current sensor |
| CN103693211A (en) * | 2013-12-25 | 2014-04-02 | 北京航天测控技术有限公司 | Test method for helicopter rotating part signal and wireless collecting device therefor |
| CN107589316A (en) * | 2017-08-25 | 2018-01-16 | 中国科学院近代物理研究所 | Charge measurement circuit |
| CN107785959A (en) * | 2018-01-05 | 2018-03-09 | 宁波大叶园林设备股份有限公司 | Gardens machine lithium cell charging program and moving average filter method circuit |
| CN111175569A (en) * | 2020-02-20 | 2020-05-19 | 中国科学院上海应用物理研究所 | Extremely narrow beam signal peak amplitude extraction method based on broadband serialization |
-
2022
- 2022-06-06 CN CN202210631212.4A patent/CN115015652B/en active Active
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH408198A (en) * | 1963-07-08 | 1966-02-28 | Kistler Instrumente Ag | Measuring amplifier for measuring electrical charges |
| US5128622A (en) * | 1990-02-06 | 1992-07-07 | Murata Mfg. Co., Ltd. | Multi-channel electrostatic sensor apparatus |
| JPH05264623A (en) * | 1992-03-17 | 1993-10-12 | Murata Mfg Co Ltd | Multichannel electrostatic sensor device |
| JPH062253U (en) * | 1992-06-10 | 1994-01-14 | 株式会社村田製作所 | Multi-channel electrostatic sensor device |
| CN203432677U (en) * | 2013-07-26 | 2014-02-12 | 浙江大学 | Dynamic calibration device of eddy current sensor |
| CN103693211A (en) * | 2013-12-25 | 2014-04-02 | 北京航天测控技术有限公司 | Test method for helicopter rotating part signal and wireless collecting device therefor |
| CN107589316A (en) * | 2017-08-25 | 2018-01-16 | 中国科学院近代物理研究所 | Charge measurement circuit |
| CN107785959A (en) * | 2018-01-05 | 2018-03-09 | 宁波大叶园林设备股份有限公司 | Gardens machine lithium cell charging program and moving average filter method circuit |
| CN111175569A (en) * | 2020-02-20 | 2020-05-19 | 中国科学院上海应用物理研究所 | Extremely narrow beam signal peak amplitude extraction method based on broadband serialization |
Non-Patent Citations (1)
| Title |
|---|
| 王敏: "束流监测器多通道数据获取系统的设计", 《中国优秀硕士学位论文全文数据库》, no. 2, pages 25 - 30 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN115015652B (en) | 2023-09-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108919282A (en) | A kind of laser radar signal moment identification system | |
| CN110274921B (en) | Full-digital two-dimensional coincidence Doppler broadening system | |
| CN109188111A (en) | Superelevation field strength, ultrashort pulse, narrowband microwave radiation field measuring system and measurement method | |
| CN105223481A (en) | Based on the partial-discharge ultrahigh-frequency signal initial time defining method of difference energy function | |
| Karthik et al. | EMI developed test methodologies for short duration noises | |
| CN111665014B (en) | Hypersonic aircraft boundary layer electron density diagnostic system based on high-frequency electrostatic probe | |
| CN108120888A (en) | New cyclotron range stability measuring system | |
| CN113504414A (en) | Method and device for detecting plasma complex dielectric constant transient microwave transmission | |
| CN105301444A (en) | Single-port detection-based cable fault locating device | |
| CN113242192B (en) | Ultra-wideband compressed sensing system and method for multi-channel radio frequency direct acquisition | |
| CN115015652A (en) | Method and system for improving electron current detection performance | |
| CN113960523A (en) | Universal ultra-wideband correction direction-finding method and system based on FPGA | |
| CN207586422U (en) | A kind of laser ranging system of total regulation | |
| Hayano et al. | High resolution BPM for FFTB | |
| CN212905422U (en) | Broadband digital frequency measurement module | |
| CN112383863B (en) | Multichannel sonobuoy signal preprocessing system and method | |
| CN113804987A (en) | Optical undersampling multi-frequency calculation method based on remainder difference characteristic value | |
| CN110794376B (en) | Ultra-wideband impulse radar receiver sensitivity measuring technology | |
| CN106405341A (en) | Method used for reducing partial discharge ultrahigh frequency signal | |
| CN109613342B (en) | Carrier rocket electromagnetic radiation emission distributed measurement method | |
| CN208190636U (en) | For phased array antenna and poor angle measurement receiver | |
| CN111044970A (en) | Real-time high-precision direction finding method and system | |
| CN109495187A (en) | A kind of TOA essence estimation method based on Hilbert transform | |
| CN114114375B (en) | Plasma hot electron measurement system and measurement method | |
| CN219302555U (en) | Pulse power frequency measurement system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| CB02 | Change of applicant information |
Address after: No. 789 Dongsheng Road, Anzhen Street, Xishan District, Wuxi City, Jiangsu Province, 214000 Applicant after: Guodian Nuclear Power Technology (Wuxi) Technology Co.,Ltd. Address before: No. 15, Houshan South Road, New Century Industrial Park, Anzhen Street, Xishan District, Wuxi City, Jiangsu Province, 214104 Applicant before: Wuxi Nuclear Power Technology Co.,Ltd. |
|
| CB02 | Change of applicant information | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |