Pulse direct acquisition system and method for particle radiation measurement

Abstract

The invention belongs to the field of particle radiation measurement technologies and related electronics, and particularly relates to a pulse direct acquisition 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 collects particle radiation charge signals output by the front end, converts the particle radiation charge signals into unipolar pulse signals and outputs the unipolar pulse signals to the signal conditioning output module. The signal conditioning output module comprises a slow forming sub-module and a fast forming sub-module; the slow shaping sub-module performs filtering shaping and amplification on the unipolar pulse signal and outputs the unipolar pulse signal to the AD acquisition module; the fast shaping sub-module filters, shapes and amplifies the unipolar pulse signal, and outputs the unipolar pulse signal as a trigger signal to the AD acquisition module; and after receiving the trigger signal, the AD acquisition module directly samples the signal output by the slow forming sub-module after waiting for corresponding time according to the time difference of the signals output by the slow forming sub-module and the fast forming sub-module.

Description

Technical Field

[0001] The present invention relates to particle radiation measurement technology and related electronics fields, and in particular to a pulse direct sampling system and method for particle radiation measurement. Background Art

[0002] The peak hold circuit is an important part of the electronics of particle radiation detection instruments. After the pulse signal output by the sensor passes through the charge sensitive preamplifier and the main amplifier, it is generally necessary to use a peak signal holding circuit, and then the ADC performs peak sampling, which 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 hold. If the peak hold circuit is cancelled and the high-speed ADC fast sampling peak search method is directly adopted, it means that higher requirements are placed on the ADC, including sampling rate, resolution, etc., which directly leads to an increase in power consumption and cost, and is not suitable for the application of general low-power, miniaturized particle radiation detection instruments. Therefore, the peak hold circuit will affect the performance parameters of the particle radiation detection instrument, such as sampling accuracy and pulse counting rate, and it is also difficult to achieve the miniaturization of the instrument structure and low energy consumption. Summary of the invention

[0003] The purpose of the present invention is to solve the above-mentioned defects in the prior art. The present invention proposes a pulse direct sampling circuit and method for particle radiation measurement, which specifically relates to a method of direct sampling based on a fast and slow shaping circuit of a pulse signal and an ADC. The detection pulse direct sampling circuit and method provided by the present invention overcome the defects of the sampling accuracy, pulse counting rate and other performance degradation caused by the peak holding circuit, as well as the difficulty in achieving miniaturization and low power consumption. At the same time, it also overcomes the disadvantages of high cost and high power consumption caused by the direct use of a high-speed ADC fast sampling peak-finding method.

[0004] To achieve the above object, the present invention is implemented through the following technical solutions.

[0005] The present invention proposes a pulse direct sampling system for particle radiation measurement, the system comprising: a charge conversion module, a signal conditioning output module and an AD acquisition module; wherein:

[0006] The charge conversion module is used to collect 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 includes a slow shaping submodule and a fast shaping submodule, wherein 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 to the AD acquisition module as a trigger signal;

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

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

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

[0011] The pole-zero 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.

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

[0013] τ f =τ0.

[0014] As an improvement of the above technical solution, the slow shaping submodule comprises in sequence: a slow shaping circuit, a first main amplifier and an output buffer; wherein,

[0015] The slow shaping circuit is used to filter and shape the unipolar pulse signal and output it to the first main amplifier;

[0016] The first main amplifier is used to amplify the voltage signal output by the slow shaping circuit by adopting an inverting amplification method, and output it to the output buffer;

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

[0018] As an improvement of the above technical solution, the fast shaping submodule comprises in sequence: a slow shaping circuit and a second main amplifier; wherein,

[0019] The fast shaping circuit is used to filter and shape the unipolar pulse signal and output it to the second main amplifier;

[0020] The second main amplifier is used to amplify the voltage signal output by the fast shaping circuit by adopting an inverting amplification method, and output it 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 submodule and the slow shaping submodule have different time constants.

[0022] As an improvement of the above technical solution, the time constant τ of the output signal of the fast shaping submodule is q and the time constant τ of the output signal of the slow shaping submodule s satisfy:

[0023] τ q = kτ s

[0024] Wherein, k is the setting coefficient, which is between 0.1 and 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] Where N is a constant, Δ∶=∶ s -τ q .

[0028] The present invention proposes a pulse direct sampling method for particle radiation measurement, which is implemented based on one of the pulse direct sampling systems for particle radiation measurement described above. The method includes:

[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 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 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 forming submodule after waiting for a corresponding time according to the time difference between the output signals of the slow forming submodule and the fast forming submodule.

[0032] As an improvement of the above technical solution, directly sampling the signal output by the slow shaping submodule after waiting for a corresponding time includes:

[0033] The signal output by the slow shaping submodule is sampled continuously for n times;

[0034] The signals sampled n times are compared, and the maximum value is taken as the peak value of the output signal of the slow shaping submodule.

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

[0036] The pulse direct sampling circuit and method of the present invention adopt fast and slow shaping circuits and ADC direct sampling methods, which not only overcome the sampling accuracy, pulse counting rate and other performance degradation caused by the peak holding circuit, and the difficulty in achieving miniaturization and low power consumption, but also overcome the high cost and high power consumption caused by the direct use of high-speed ADC fast sampling peak search method. In addition, the pulse direct sampling circuit and method can be widely used in the measurement of charged particles with a deposition energy greater than 25keV. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

[0040] The technical solution of the present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0041] like Figure 1 As shown, it is a block diagram of the overall composition of the circuit of the present invention.

[0042] A pulse direct sampling system for particle radiation measurement of the present invention 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 includes a slow shaping submodule and a fast shaping submodule, wherein 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 to the AD acquisition module as a trigger signal;

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

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

[0047] The charge-sensitive preamplifier circuit is used to collect the charge signal radiated by the particles, convert it into a voltage to obtain a bipolar pulse signal, and output it to the pole-zero cancellation circuit;

[0048] The pole-zero 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.

[0049] The slow shaping submodule includes in sequence: a slow shaping circuit, a first main amplifier and an output buffer; wherein,

[0050] The slow shaping circuit is used to filter and shape the unipolar pulse signal and output it to the first main amplifier;

[0051] The first main amplifier is used to amplify the voltage signal output by the slow shaping circuit by adopting an inverting amplification method, and output it to the output buffer;

[0052] The output buffer is used to output the signal to the AD acquisition module in a voltage following manner.

[0053] The fast shaping submodule includes: a slow shaping circuit and a second main amplifier in sequence; wherein,

[0054] The fast shaping circuit is used to filter and shape the unipolar pulse signal and output it to the second main amplifier;

[0055] The second main amplifier is used to amplify the voltage signal output by the fast shaping circuit by adopting an inverting amplification method, and output it to the AD acquisition module as a trigger signal.

[0056] like Figure 2 As shown, it is a connection block diagram of a pulse direct sampling circuit for particle radiation measurement provided by Embodiment 1 of the present invention; 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 a pole-zero cancellation circuit;

[0058] The pole-zero cancellation circuit is connected to the fast forming circuit and the slow forming circuit respectively;

[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 solution, the charge sensitive preamplifier performs voltage conversion on the charge signal generated by the energy deposited by the charged particles in the detector inputted from the front end, and outputs it to the pole-zero phase cancellation circuit;

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

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

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

[0066] As one of the improvements of the above technical solution, the output signals of the fast shaping circuit and the slow shaping circuit have different time constants;

[0067] As one of the improvements of the above technical solution, the first main amplifier adopts an inverting amplification method to amplify the amplitude of the voltage signal output by the slow shaping circuit and output it to the output buffer;

[0068] As one of the improvements of the above technical solution, the second main amplifier adopts an inverting amplification method to amplify the amplitude of the voltage signal output by the fast shaping circuit and output it;

[0069] As one of the improvements of the above technical solution, the output buffer adopts a voltage following mode for output.

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

[0071] According to the time difference between the output signals of the fast and slow shaping circuits, after waiting for a corresponding time, the AD collector starts and directly samples the output signal of 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] Example 2

[0074] like Figure 3 As shown, it is a flow chart of a pulse direct sampling method for particle radiation measurement provided in Example 2 of the present invention.

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

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

[0077] : f =C f ·R f

[0078] Among them, C f is in the pF range, R f It is in the MΩ range.

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

[0080] τ0=C0·R0

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

[0082] τ f =τ0

[0083] Among them, C0 is tens of nF, R0 is 10 4 Ω level.

[0084] Step 2) Calculate the time constant of the slow forming circuit. The method and requirements are as follows:

[0085] τ s =C 1a ·R 1a =C 1b ·R 1b

[0086] Among them: s In microseconds (uS), C 1a , C 1b It is in the order of tens to hundreds of pF, R 1a , R 1b It is in the order of several kΩ to tens of kΩ.

[0087] Step 3) Calculate the time constant of the fast forming circuit. The method and requirements are as follows:

[0088] τ q =C 2a ·R 2a =C 2b ·R 2b

[0089] Among them, τ q It is in the order of several hundred nS, C 2a , C 2b It is in the order of tens to hundreds of pF, R 2a , R 2bIt is in the order of several kΩ to tens of kΩ.

[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 receiving the front-end silicon semiconductor detector, τ s The general choice is 1 to 2 microseconds.

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

[0094] Δτ=τ s -τ q

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

[0096] ΔT=N·Δτ

[0097] Wherein, N is a constant, and generally takes a value of 3 to 5.

[0098] Step 7) The fast forming signal outputted from step 3) is used as a start signal to trigger the back-end ADC collector. After waiting for the acquisition waiting time ΔT calculated from step 6), the ADC collector continuously samples the output signal of the output buffer. The sampling number n is generally selected to be n≥3.

[0099] Step 8) Compare the ADC sampling signals and take the maximum value as the peak value of the output signal of the slow shaping circuit.

[0100] From the above specific description of the present invention, it can be seen that the pulse direct sampling circuit and method of the present invention adopt fast and slow shaping circuits and ADC direct sampling methods, which not only overcome the sampling accuracy, pulse counting rate and other performance degradation caused by the peak holding circuit, as well as the difficulty in achieving miniaturization and low power consumption, but also overcome the high cost and high power consumption caused by the direct use of high-speed ADC fast sampling peak search method. In addition, the pulse direct sampling circuit and method can be widely used in the measurement of charged particles with a deposition energy greater than 25keV.

[0101] The invention relates to a pulse direct sampling circuit and method for particle radiation measurement, comprising 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; the charge sensitive preamplifier performs voltage conversion on a charge signal inputted from the front end and generated by the energy deposited in a detector by the incident charged particles, and outputs the same; the pole zero cancellation circuit converts the bipolar pulse signal outputted by the charge sensitive preamplifier into a unipolar pulse output; the slow shaping circuit performs filtering and shaping on the unipolar pulse outputted by the pole zero cancellation circuit, and outputs the same; the main amplifier 1 performs amplitude amplification on the voltage signal outputted by the slow shaping circuit, and outputs the same; the fast shaping circuit performs filtering and shaping on the unipolar voltage pulse outputted by the pole zero cancellation circuit, and outputs the same; the second main amplifier performs amplitude amplification on the voltage signal outputted by the fast shaping circuit, and outputs the same; the output buffer performs impedance matching on the voltage signal outputted by the first main amplifier, and outputs the same; the pulse direct sampling circuit and method can realize the measurement of charged particles with a deposition energy greater than 25keV.

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention is described in detail with reference to the embodiments, it should be understood by those skilled in the art that any modification or equivalent replacement of the technical solutions of the present invention does not depart from the spirit and scope of the technical solutions of the present invention and should be included in the scope of the claims of the present invention.

Claims

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

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

5. The pulse direct sampling system for particle radiation measurement according to claim 1, characterized in that: The fast shaping submodule includes: a slow shaping circuit and a second main amplifier in sequence; wherein, The fast shaping 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 shaping circuit by adopting an inverting amplification method, and output it to the AD acquisition module as a trigger signal.

6. The pulse direct sampling system for particle radiation measurement according to claim 1, characterized in that: The output signals of the fast shaping submodule and the slow shaping submodule have 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 fast shaping submodule q and the time constant τ of the output signal of the slow shaping submodule s satisfy: t q =kτ s Wherein, k is the setting coefficient, which is between 0.1 and 0.

3.

8. The pulse direct sampling system for particle radiation measurement according to claim 7, characterized in that: The calculation formula for 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 to 8, characterized in that: The method comprises: 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; 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 to the AD acquisition module as a trigger signal; After receiving the trigger signal, the AD acquisition module directly samples the signal output by the slow forming submodule after waiting for a corresponding time according to the time difference between the output signals of the slow forming submodule and the fast forming submodule.

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

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