A pulsed direct sampling system and method for particle radiation measurements

Abstract

The present application belongs to the field of particle radiation measurement technology and related electronics, and particularly relates to a pulse direct sampling system and method for particle radiation measurement. The system comprises a charge conversion module, a signal conditioning output module and an AD acquisition module. The charge conversion module acquires the particle radiation charge signal output from the front end, converts it into a unipolar pulse signal and outputs it to the signal conditioning output module. The signal conditioning output module comprises a slow shaping submodule and a fast shaping submodule. The slow shaping submodule filters, shapes and amplifies the unipolar pulse signal and outputs it to the AD acquisition module. The fast shaping submodule filters, shapes and amplifies the unipolar pulse signal and outputs it as a trigger signal to the AD acquisition module. After receiving the trigger signal, the AD acquisition module directly samples the signal output by the slow shaping submodule according to the time difference between the signals output by the slow shaping submodule and the fast shaping submodule after waiting for a corresponding time.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of particle radiation measurement technology and related electronics, in particular to a pulse direct sampling system and method for particle radiation measurement. BACKGROUND

[0002] The peak holding circuit is an important part of the electronics of particle radiation detection instrument. After the pulse signal output by the sensor is processed by the charge-sensitive preamplifier and the main amplifier, a peak signal holding circuit is generally used, and then the peak value is sampled by the ADC. This not only increases the size and power consumption of the instrument, but also causes the linearity of the voltage pulse signal to deteriorate after the peak value is held. If the peak holding circuit is cancelled and a high-speed ADC is directly used for fast sampling and peak searching, it means that higher requirements are put forward to the ADC, including sampling rate, resolution, etc., which directly leads to an increase in power consumption and cost, and is not suitable for general low-power and small-sized particle radiation detection instruments. Therefore, the peak holding circuit affects the sampling accuracy and pulse count rate of the particle radiation detection instrument, and it is also difficult to realize the miniaturization of the instrument structure and the low power consumption of the energy consumption. SUMMARY

[0003] The purpose of the present application is to solve the above-mentioned defects in the prior art. The present application provides a pulse direct sampling circuit and method for particle radiation measurement, which is particularly based on a pulse signal fast and slow shaping circuit and an ADC direct sampling method. The detection pulse direct sampling circuit and method provided by the present application overcome the performance decline in sampling accuracy, pulse count rate, etc. caused by the peak holding circuit, and the defects in miniaturization and low power consumption, etc. It also overcomes the high cost and high power consumption caused by directly using a high-speed ADC for fast sampling and peak searching.

[0004] To achieve the above-mentioned purpose, the present application realizes the technical scheme as follows.

[0005] The present application provides a pulse direct sampling system for particle radiation measurement, which comprises a charge conversion module, a signal conditioning output module and an AD acquisition module, wherein,

[0006] The charge conversion module is used to acquire the particle radiation charge signal output by the front end, convert it into a unipolar pulse signal, and output it to the signal conditioning output module;

[0007] The signal conditioning output module comprises a slow shaping submodule and a fast shaping submodule, wherein the slow shaping submodule is used to filter and shape and amplify the unipolar pulse signal and output it to the AD acquisition module; and the fast shaping submodule is used to filter and shape and amplify the unipolar pulse signal and output it as a trigger signal to the AD acquisition module;

[0008] The AD acquisition module is configured to, after receiving the trigger signal, according to a time difference between output signals of the slow shaping sub-module and the fast shaping sub-module, directly sample the signal output by the slow shaping sub-module after waiting for a corresponding time.

[0009] As an improvement of the above technical solution, the charge conversion module sequentially comprises a charge-sensitive preamplifier and a pole-zero cancellation circuit, wherein,

[0010] The charge-sensitive preamplifier is configured to receive a charge signal formed by particle radiation to a front-end sensor, convert the charge signal into a bipolar pulse signal, and output the bipolar pulse signal to the pole-zero cancellation circuit.

[0011] The pole-zero cancellation circuit is configured to convert the bipolar pulse signal output by the charge-sensitive preamplifier into a unipolar pulse signal, and output the unipolar pulse signal to a signal conditioning and output module.

[0012] As an improvement of the above technical solution, a time constant τ of the charge-sensitive preamplifier and a time constant τ0 of the pole-zero cancellation circuit satisfy: f

[0013] τ f = τ0.

[0014] As an improvement of the above technical solution, the slow shaping sub-module sequentially comprises a slow shaping circuit, a first main amplifier, and an output buffer, wherein,

[0015] The slow shaping circuit is configured to filter and shape the unipolar pulse signal, and output the unipolar pulse signal to the first main amplifier.

[0016] The first main amplifier is configured to amplify the voltage signal output by the slow shaping circuit in an inverting amplification manner, and output the voltage signal to the output buffer.

[0017] The output buffer is configured to output the voltage signal to the AD acquisition module in a voltage follower manner.

[0018] As an improvement of the above technical solution, the fast shaping sub-module sequentially comprises a slow shaping circuit and a second main amplifier, wherein,

[0019] The fast shaping circuit is configured to filter and shape the unipolar pulse signal, and output the unipolar pulse signal to the second main amplifier.

[0020] The second main amplifier is configured to amplify the voltage signal output by the fast shaping circuit in an inverting amplification manner, and output the voltage signal to the AD acquisition module as a trigger signal.

[0021] As an improvement of the above technical solution, the output signals of the fast shaping sub-module and the slow shaping sub-module have different time constants.​

[0022] As an improvement of the above technical solution, the time constant τ of the fast shaping sub-module output signal q And the time constant τ of the slow shaping sub-module output signal s Satisfy:

[0023] τ q =kτ s

[0024] Wherein, k is a set coefficient, taking 0.1-0.3.

[0025] As an improvement of the above technical solution, the calculation formula of the corresponding waiting time ΔT is:

[0026] ΔT=N·Δ∶

[0027] Wherein, N is a constant, Δ∶=∶ s -τ q .

[0028] The present application proposes a pulse direct sampling method for particle radiation measurement, which is realized based on the pulse direct sampling system for particle radiation measurement described above, and the method comprises:

[0029] The charge conversion module receives the charge signal formed by the particle radiation to the front-end sensor, converts it into a unipolar pulse signal, and outputs it to the signal conditioning output module;

[0030] The slow shaping sub-module of the signal conditioning output module filters and shapes the unipolar pulse signal and amplifies it, and outputs it to the AD acquisition module; the fast shaping sub-module of the signal conditioning output module filters and shapes the unipolar pulse signal and amplifies it, and outputs it to the AD acquisition module as a trigger signal;

[0031] After receiving the trigger signal, the AD acquisition module directly samples the signal output by the slow shaping sub-module after waiting for a corresponding time according to the time difference between the output signals of the slow shaping sub-module and the fast shaping sub-module.

[0032] As an improvement of the above technical solution, the direct sampling of the signal output by the slow shaping sub-module after waiting for a corresponding time comprises:

[0033] Sampling the signal output by the slow shaping sub-module continuously n times;

[0034] Comparing the n times of sampling signals, taking the maximum value as the peak value of the slow shaping sub-module output signal.

[0035] Compared with the prior art, the present application has the following advantages:

[0036] The pulse direct sampling circuit and method of the present application adopts fast and slow shaping circuits and an ADC direct sampling method, which not only overcomes the performance decline of sampling accuracy, pulse counting rate and other performances caused by the peak holding circuit, and the defects of difficult miniaturization and low power consumption, but also overcomes the high cost and high power consumption caused by the fast sampling peak search method of directly using a high-speed ADC. In addition, the pulse direct sampling circuit and method can be widely applied to charged particle measurement with a deposition energy greater than 25keV. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 is the overall composition block diagram of the system of the present application.

[0038] Figure 2 is a pulse direct sampling circuit connection block diagram for particle radiation measurement provided by an embodiment of the present application;

[0039] Figure 3 is a pulse direct sampling method flow chart for particle radiation measurement provided by an embodiment of the present application. DETAILED DESCRIPTION

[0040] The technical solutions of the present application will be described in detail below in combination with the drawings and embodiments.

[0041] As shown in Figure 1 , it is the overall composition block diagram of the circuit of the present application.

[0042] The pulse direct sampling system for particle radiation measurement of the present application comprises a charge conversion module, a signal conditioning output module and an AD acquisition module; wherein,

[0043] The signal conversion module is used to receive the charge signal formed by the particle radiation to the front-end sensor, convert it into a unipolar pulse signal, and output it to the signal conditioning output module;

[0044] The signal conditioning output module comprises a slow shaping sub-module and a fast shaping sub-module, wherein the slow shaping sub-module is used to filter and shape and amplify the unipolar pulse signal, and output it to the AD acquisition module; the fast shaping sub-module is used to filter and shape and amplify the unipolar pulse signal, and output it as a trigger signal to the AD acquisition module;

[0045] The AD acquisition module is used to directly sample the signal output by the slow shaping sub-module after waiting for a corresponding time according to the time difference of the signals output by the slow shaping sub-module and the fast shaping sub-module after receiving the trigger signal.

[0046] The charge conversion module comprises, in sequence, a charge-sensitive preamplifier circuit and a pole-zero cancellation circuit; wherein,

[0047] The charge-sensitive preamplifier is used for collecting the charge signal of particle radiation, voltage conversion of the charge signal to obtain a bipolar pulse signal, and output to the pole-zero cancellation circuit.

[0048] The pole-zero cancellation circuit is used for converting the bipolar pulse signal output by the charge-sensitive preamplifier into a unipolar pulse signal and outputting the unipolar pulse signal to the signal conditioning and output module.

[0049] The slow shaping sub-module sequentially comprises a slow shaping circuit, a first main amplifier and an output buffer.

[0050] The slow shaping circuit is used for filtering and shaping the unipolar pulse signal and outputting the unipolar pulse signal to the first main amplifier.

[0051] The first main amplifier is used for performing amplitude amplification on the voltage signal output by the slow shaping circuit in an inverting amplification mode and outputting the voltage signal to the output buffer.

[0052] The output buffer is used for outputting the signal to the AD acquisition module in a voltage follower mode.

[0053] The fast shaping sub-module sequentially comprises a slow shaping circuit and a second main amplifier.

[0054] The fast shaping circuit is used for filtering and shaping the unipolar pulse signal and outputting the unipolar pulse signal to the second main amplifier.

[0055] The second main amplifier is used for performing amplitude amplification on the voltage signal output by the fast shaping circuit in an inverting amplification mode and outputting the voltage signal to the AD acquisition module as a trigger signal.

[0056] As shown in FIG. 1, a pulse direct sampling circuit connection block diagram for particle radiation measurement is provided for Embodiment 1 of the present application. Figure 2 The direct sampling circuit comprises a charge-sensitive preamplifier, a pole-zero cancellation circuit, a slow shaping circuit, a first main amplifier, an output buffer, a fast shaping circuit and a second main amplifier.

[0057] The charge-sensitive preamplifier is connected to the pole-zero cancellation circuit.

[0058] The pole-zero cancellation circuit is connected to the fast shaping circuit and the slow shaping circuit.

[0059] The slow shaping circuit is connected to the first main amplifier.

[0060] The fast shaping circuit is connected to the second main amplifier.

[0061] The first main amplifier is connected to the output buffer.

[0062] As one of the improvements of the above technical solutions, the charge-sensitive preamplifier converts the charge signal generated by the charged particles depositing energy in the detector into a voltage signal and outputs the voltage signal to the pole-zero cancellation circuit.

[0063] As one of the improvements of the above technical solutions, the pole-zero cancellation circuit converts the bipolar pulse signal output by the charge-sensitive preamplifier into a unipolar signal and outputs the unipolar signal to the fast shaping circuit and the slow shaping circuit, respectively.

[0064] As one of the improvements of the above technical solutions, the slow shaping circuit filters and shapes the unipolar pulse signal output by the pole-zero cancellation circuit and outputs the signal to the first main amplifier.

[0065] As one of the improvements of the above technical solutions, the fast shaping circuit filters and shapes the unipolar pulse signal output by the pole-zero cancellation circuit and outputs the signal to the second main amplifier.

[0066] As one of the improvements of the above technical solutions, the fast shaping circuit and the slow shaping circuit output signals with different time constants.

[0067] As one of the improvements of the above technical solutions, the first main amplifier adopts an inverting amplification mode to amplify the voltage signal output by the slow shaping circuit in amplitude and outputs the signal to the output buffer.

[0068] As one of the improvements of the above technical solutions, the second main amplifier adopts an inverting amplification mode to amplify the voltage signal output by the fast shaping circuit in amplitude and outputs the signal.

[0069] As one of the improvements of the above technical solutions, the output buffer adopts a voltage follower mode and outputs the signal.

[0070] The pulse direct sampling method for particle radiation measurement is based on the different time constants of the output signals of the fast shaping circuit and the slow shaping circuit, and the fast shaping signal output by the second main amplifier is used as a trigger to start the rear-end AD sampler.

[0071] According to the time difference of the output signals of the fast shaping circuit and the slow shaping circuit, the AD sampler is started after waiting for a corresponding time and directly samples the signal output by the output buffer.

[0072] Based on the comparison of the ADC sampling signals, the maximum value is taken as the peak value of the output signal of the slow shaping circuit.

[0073] Embodiment 2

[0074] As shown in Figure 3 FIG. 1 is a flowchart of a pulse direct sampling method for particle radiation measurement according to Embodiment 2 of the present application.

[0075] The working steps of the pulse direct acquisition method for particle radiation measurement include:

[0076] Step 1) Calculate the time constant of the charge-sensitive preamplifier, as follows:

[0077] : f = C f · R f

[0078] Wherein, C f is of the order of pF, and R f is of the order of MΩ.

[0079] The time constant of the pole-zero cancellation circuit is calculated as follows:

[0080] τ0 = C0·R0

[0081] According to the pole-zero cancellation principle, the resistance and capacitance parameters are selected as follows:

[0082] τ f = τ0

[0083] Wherein, C0 is of the order of tens of nF, and R0 is of the order of 10 4 Ω.

[0084] Step 2) Calculate the time constant of the slow shaping circuit, as follows:

[0085] τ s = C 1a · R 1a = C 1b · R 1b

[0086] Wherein, τ s is of the order of microseconds (uS), C 1a , C 1b is of the order of tens to hundreds of pF, and R 1a , R 1b is of the order of several k to several tens of kΩ.

[0087] Step 3) Calculate the time constant of the fast shaping circuit, as follows:

[0088] τ q = C 2a · R 2a = C 2b · R 2b

[0089] Wherein, τ q is of the order of hundreds of nS, C 2a , C 2b is of the order of tens to hundreds of pF, and R 2a , R 2bFor several k to several tens of kΩ order.

[0090] Step 4) According to steps 2) and 3), the fast and slow shaping time constants are required to meet the following conditions:

[0091] τ q =(0.1~0.3)τ s

[0092] For the charge-sensitive preamplifier received by the silicon semiconductor detector of the front end, τ s Generally selected as 1~2 microseconds.

[0093] Step 5) According to steps 2) and 3), the shaping time difference of the fast and slow shaping circuits is calculated, that is,

[0094] Δτ=τ s -τ q

[0095] Step 6) According to step 5), the ADC acquisition waiting time is calculated, and the calculation method is as follows:

[0096] ΔT=N·Δτ

[0097] Wherein, N is a constant, generally 3~5.

[0098] Step 7) According to the fast shaping signal output by step 3), the starting signal of the trigger rear-end ADC collector is taken as the starting signal, and after waiting for the acquisition waiting time ΔT calculated in step 6), the ADC collector continuously samples the output signal of the output buffer, and the sampling number n is generally selected n≥3.

[0099] Step 8) The ADC sampling signal is compared, and the maximum value is taken as the peak value of the slow shaping circuit output signal.

[0100] From the above specific description of the present application, it can be seen that the pulse direct sampling circuit and method of the present application adopts fast and slow shaping circuits and ADC direct sampling method, which not only overcomes the performance decline of sampling accuracy, pulse counting rate and other performances caused by the peak holding circuit, and the difficulty in realizing miniaturization, low power consumption and other defects, but also overcomes the high cost and high power consumption caused by directly using high-speed ADC fast sampling peak search method. In addition, the pulse direct sampling circuit and method can be widely applied to charged particle measurement with a deposition energy greater than 25keV.

[0101] The present application relates to a kind of pulse direct acquisition circuit and method for particle radiation measurement, including charge sensitive preamplifier, pole zero cancellation circuit, slow shaping circuit, first main amplifier, output buffer, fast shaping circuit, second main amplifier;The charge sensitive preamplifier carries out voltage conversion to the charge signal generated by the energy deposited in detector by charged particle incidence in front end input and exports;The pole zero cancellation circuit converts the bipolar pulse signal exported by charge sensitive preamplifier into unipolar pulse output;The slow shaping circuit is filtered to the unipolar pulse exported by pole zero cancellation circuit and exports;The main amplifier 1 is amplified to the voltage signal exported by slow shaping circuit and exports;The fast shaping circuit is filtered to the unipolar voltage pulse exported by pole zero cancellation circuit and exports;The second main amplifier is amplified to the voltage signal exported by fast shaping circuit and exports;The output buffer is impedance matched to the voltage signal exported by first main amplifier and exports;This pulse direct acquisition circuit and method can realize the measurement to the charged particle of deposited energy greater than 25keV.

[0102] Finally, it should be explained that the above examples are only used to illustrate the technical solutions of the present application, but not limited. Although the present application is described in detail with reference to the examples, those skilled in the art should understand that the technical solutions of the present application are modified or replaced by equivalent, without departing from the spirit and scope of the present application, which should be covered in the scope of claims of the present application.

Claims

1. A pulse direct sampling system for particle radiation measurement, characterized in that, The system includes: a charge conversion module, a signal conditioning and output module, and an AD acquisition module; wherein... The charge conversion module is used to collect the particle radiation charge signal output from the front end, convert it into a unipolar pulse signal, and output it to the signal conditioning output module. The signal conditioning output module includes a slow shaping submodule and a fast shaping submodule. The slow shaping submodule is used to filter, shape, and amplify the unipolar pulse signal and output it to the AD acquisition module. The fast shaping submodule is used to filter, shape, and amplify the unipolar pulse signal and output it as a trigger signal to the AD acquisition module. The AD acquisition module is used to directly sample the signal output by the slow forming submodule after receiving the trigger signal, based on the time difference between the output signals of the slow forming submodule and the fast forming submodule, and after waiting for a corresponding time.

2. The pulse direct sampling system for particle radiation measurement according to claim 1, characterized in that, The charge conversion module comprises, in sequence, a charge-sensitive preamplifier circuit and a zero-phase cancellation circuit; wherein... The charge-sensitive preamplifier circuit is used to receive the charge signal formed by particle radiation to the front-end sensor, convert it into a voltage to obtain a bipolar pulse signal, and output it to the zero-pole cancellation circuit. The zero-pole cancellation circuit is used to convert the bipolar pulse signal output by the charge-sensitive preamplifier circuit into a unipolar pulse signal and output it to the signal conditioning output module.

3. The pulse direct sampling system for particle radiation measurement according to claim 2, characterized in that, The time constant τ of the charge-sensitive preamplifier circuit f The time constant τ0 of the pole-zero cancellation circuit satisfies: t f = τ0.

4. The pulse direct sampling system for particle radiation measurement according to claim 1, characterized in that, The slow-shaping submodule sequentially includes: a slow-shaping circuit, a first main amplifier, and an output buffer; wherein... The slow shaping circuit is used to filter and shape the unipolar pulse signal and output it to the first main amplifier. The first main amplifier is used to amplify the voltage signal output by the slow-shaping circuit using an inverting amplification method and output it to the output buffer. The output buffer is used to output the signal to the AD acquisition module in a voltage follower manner.

5. The pulse direct sampling system for particle radiation measurement according to claim 1, characterized in that, The fast prototyping submodule sequentially includes: a slow prototyping circuit and a second main amplifier; wherein... The fast prototyping circuit is used to filter and shape the unipolar pulse signal and output it to the second main amplifier. The second main amplifier is used to amplify the voltage signal output by the fast forming circuit using an inverting amplification method, and output it as a trigger signal to the AD acquisition module.

6. The pulse direct sampling system for particle radiation measurement according to claim 1, characterized in that, The fast forming submodule and the slow forming submodule output signals with different time constants.

7. The pulse direct sampling system for particle radiation measurement according to claim 1 or 6, characterized in that, The time constant τ of the output signal of the rapid prototyping submodule q The time constant τ of the output signal of the slow forming submodule s satisfy: t q =kτ s Where k is a set coefficient, ranging from 0.1 to 0.

3.

8. The pulse direct sampling system for particle radiation measurement according to claim 7, characterized in that, The formula for calculating the corresponding waiting time ΔT is: ΔT=N·Δτ Where N is a constant, Δτ=τ s -τ q .

9. A pulse direct sampling method for particle radiation measurement, implemented based on the pulse direct sampling system for particle radiation measurement according to any one of claims 1-8, characterized in that, The method includes: The charge conversion module receives the charge signal generated by particle radiation to the front-end sensor, converts it into a unipolar pulse signal, and outputs it to the signal conditioning output module; The slow-shaping submodule of the signal conditioning output module filters, shapes, and amplifies the unipolar pulse signal and outputs it to the AD acquisition module; the fast-shaping submodule of the signal conditioning output module filters, shapes, and amplifies the unipolar pulse signal and outputs it as a trigger signal to the AD acquisition module. After receiving the trigger signal, the AD acquisition module directly samples the signal output by the slow forming submodule based on the time difference between the output signals of the slow forming submodule and the fast forming submodule, and waits for the corresponding time.

10. The pulse direct sampling method for particle radiation measurement according to claim 9, characterized in that, The step of directly sampling the signal output by the slow-forming submodule after waiting for a corresponding time includes: The signal output by the slow forming submodule is sampled n times consecutively. The signal is compared n times, and the maximum value is taken as the peak value of the output signal of the slow forming submodule.

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