CN105301627B - A kind of energy spectrum analysis method, energy spectrum analysis system and gamma-ray detection system - Google Patents
A kind of energy spectrum analysis method, energy spectrum analysis system and gamma-ray detection system Download PDFInfo
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Abstract
The present invention relates to a kind of energy spectrum analysis methods, it includes converting particle energy to inceptive impulse signal, by the inceptive impulse signal processing at step pulse signal, it further includes being converted into rectangular pulse signal after the step pulse signal is carried out pulse shaping, it is a definite value to make the impulse amplitude of rectangular pulse signal, the impulse amplitude of the pulse width and step pulse signal that make rectangular pulse signal is at correspondence, the pulse width and corresponding step-by-step counting for measuring rectangular pulse signal obtain its pulse width spectra, then pulse width spectra is converted to by pulse amplitude spectrum according to the correspondence of rectangular pulse width and step pulse amplitude, or pulse width spectra is converted directly into the power spectrum of particle according to the correspondence of rectangular pulse width and particle energy.The invention further relates to a kind of energy spectrum analysis system and a kind of gamma-ray detection systems.The present invention solves the problems, such as energy spectrum analysis process in the prior art because being difficult to improve integrated level comprising complicated A/D conversion circuits.
Description
Technical field
The present invention relates to particle detector, specifically a kind of energy spectrum analysis method, energy spectrum analysis system and gamma ray are visited
Examining system.
Background technology
For particle detector, most important two physical quantitys are exactly energy and flux, to the two physical quantitys into
The system of row statistical analysis is exactly the energy spectrum analysis system of particle detector, that is, usually said multi-channel analyzer.Particle
Detector converts particle energy to electronic pulse signal, and a particle generally produces a pulse, and the amplitude of pulse, which corresponds to, sinks
Long-pending particle energy, and umber of pulse then corresponds to population, and step-by-step counting, i.e., so-called multiple tracks are carried out according to the size of impulse amplitude
Analysis may finally be obtained by the population statistical result of Energy distribution to get to the power spectrum of particle.
It can be seen that energy spectrum analysis system or so-called multi-channel analyzer, essence is pulse amplitude spectrum analysis system,
Two basic measurement tasks are mainly completed, is to be counted to pulse first, followed by impulse amplitude is detected.Power spectrum
The performance boost of analysis system is also mainly reflected in two aspects：One is improving counting rate, i.e. counting rate；The second is improving
Amplitude detection precision, i.e. energy resolution.
Although the energy spectrum analysis system of early stage is the simulation spectroscopy systems analyzed based on analog signal, with computer sum number
The rapid development of word technology, modern energy spectrum analysis system are then all based on the digital spectroscopy systems of Digital Signal Analysis.Relatively
For, digital spectroscopy systems are more convenient for carrying out storage, processing and the transmission of power spectrum.
In order to realize the accurate measurement of impulse amplitude, it is necessary to be shaped accordingly to impulse waveform, main purpose is
Make top flattening while compressed pulse widths.Currently, there are mainly two types of typical energy spectrum analysis systems：One is being based on
Simulate the molding energy spectrum analysis system of quasi- Gauss, flow diagram as shown in Figure 1, the system to the rate request of analog-to-digital conversion not
Height, but the multilevel simulation circuit for filtering and shaping is needed, thus it is unfavorable for the integrated of system；Another kind is based on number
The energy spectrum analysis system of trapezoidal shaping, shown in flow diagram 2, the analog front circuit which needs is greatly simplified, thus
Be very beneficial for the system integration, but the requirement higher to A/D converter, it usually needs at a high speed with high-precision A/D converter.
It can be seen that above-mentioned existing energy spectrum analysis system is all based on the direct measurement of impulse amplitude, thus needs essence
Close and complicated A/D conversion circuits, therefore, however it remains the problem of integrated level is difficult to improve.
Invention content
The present invention makes in view of the above-mentioned problems, its object is to solve in the prior art energy spectrum analysis system because
The problem of to be difficult to improve integrated level comprising complicated A/D conversion circuits.
Technical scheme is as follows：
A kind of energy spectrum analysis method includes the steps that converting particle energy to inceptive impulse signal, further includes as follows
Step：
1. the inceptive impulse signal is made step pulse by integrating enhanced processing as step pulse signal Au (t)
The amplitude A of signal is corresponding with particle energy E.
2. being converted into rectangular pulse signal after step pulse signal is carried out pulse shaping, make the pulse of rectangular pulse signal
Amplitude is a definite value, and the impulse amplitude A of the pulse width W for making rectangular pulse signal and step pulse signal are closed in one-to-one correspondence
System.
3. measuring the pulse width of rectangular pulse signal and carrying out step-by-step counting to rectangular pulse signal, according to one measured
Series of pulses width and the statistical result of corresponding step-by-step counting obtain pulse width spectra.
4. pulse width spectra is converted to impulse amplitude according to the correspondence of rectangular pulse width and step pulse amplitude
It composes, or pulse width spectra is converted directly into the power spectrum of particle according to the correspondence of rectangular pulse width and particle energy.
Further, the step method that 2. middle step pulse signal is converted into rectangular pulse signal includes following step
Suddenly：
a：By step pulse signal Au (t) by amplifying and forming is converted into shaped pulse signal h (A, t), wherein h
The pulse width and impulse amplitude of (A, t) are limited nonzero value.
b：It converts the shaped pulse signal h (A, t) that step a is obtained to rectangular pulse letter using threshold value comparison method is determined
Number, the impulse amplitude of the rectangular pulse signal is certain value, pulse width W and the step pulse signal of the rectangular pulse signal
Amplitude A is at continuous monotonic functional relationship W=F (A).
Further, the shaped pulse signal in the step a has functional form Af (t), and wherein A is step pulse
The impulse amplitude of signal, f (t) are impulse functions linearly or nonlinearly, which has non-zero and be limited pulse
Width and impulse amplitude, and the rising edge on peak value of pulse both sides and failing edge are respectively continuous monotonic function f1(t) and f2(t)。
The step b's determines the T that rising edge threshold value in threshold value comparison method is non-zero1, failing edge threshold value is the T of non-zero2, to
The width W of rectangular pulse signal and the amplitude A of step pulse signal are obtained into fixed functional relation
Further, the shaped pulse signal in the step a has functional form f (t/A), and wherein A is step pulse
The impulse amplitude of signal, f (t/A) are impulse functions linearly or nonlinearly, which has non-zero and be limited arteries and veins
Width and impulse amplitude are rushed, and the rising edge on peak value of pulse both sides and failing edge are respectively continuous monotonic function f1(t/A) and f2
(t/A)。
b：The rising edge threshold value in threshold value comparison method of determining of the step b is T1, failing edge threshold value is T2, to obtain rectangle arteries and veins
The width W of signal and the amplitude A of step pulse signal are rushed into fixed linear functional relation
Further, the shaped pulse signal is linear triangular pulse or trapezoidal pulse, or is nonlinear
Exponential decay pulse or quasi- Gaussian pulse.
It is corresponding with a kind of energy spectrum analysis system with above-mentioned energy spectrum analysis method comprising the reception for converting particle energy is visited
Head, receiving transducer are used to convert particle energy to inceptive impulse current signal, further include preamplifier, pole-zero cancellation electricity
Road, pulse former, the programmable logic chip determined threshold comparator or trigger and include counter or timer.Its
In, inceptive impulse signal is impulse amplitude step pulse corresponding with particle energy by integrating enhanced processing by preamplifier
Signal；Pole-zero cancellation circuit is for converting step pulse signal to exponential decay pulse signal and amplifying signal amplitude；Arteries and veins
Punching forming circuit is used to convert exponential decay pulse signal to the shaped pulse signal with certain pulse width and amplitude, fixed
Threshold comparator or trigger are used to convert the shaped pulse signal to rectangular pulse signal, make the pulse width of the rectangular pulse
Degree is fixed value, and the pulse width of the rectangular pulse is made to be equal to pulse width of the shaped pulse signal at threshold value；It is programmable to patrol
Pulse width and step-by-step counting that chip is used to measure rectangular pulse signal are collected, and wide according to a series of pulses obtained are measured
Degree and corresponding counting are worth to pulse width spectra, can be by pulse finally by the correspondence of pulse width and impulse amplitude
Width spectrum is converted to pulse amplitude spectrum, or is directly turned pulse width spectra according to the correspondence of pulse width and particle energy
It is changed to the power spectrum of particle.
Further, time domain waveform of the pulse former using shock response and the impulse waveform phase one after forming
The quasi- triangular pulse wave-shaping circuit caused.
Further, the quasi- triangular pulse wave-shaping circuit will be referred to using the logarithm operation pulse amplifying circuit of simulation
Number decaying pulse signal is converted to the right angled triangle pulse of linear attenuation.
The process that further programmable logic chip carries out pulse width detection is：Rectangular pulse signal is led to first
Cross d type flip flop and clock signal synchronization；Then step-by-step counting is carried out to clock signal with rectangular pulse signal control counter, then
Count value represents the pulse width of rectangular pulse signal.Programmable logic chip carry out step-by-step counting process be：According to rectangle
The correspondence W=F (A) of the pulse width of pulse and the impulse amplitude of step pulse, the pulse width of rectangular pulse signal
Count value is segmented W by functional relation linearly or nonlinearlyn=F (An) and An+1=An+ Δ, wherein n are non-negative integer, and Δ is
Fixed value makes each section of pulse width W correspond to a storage address, wherein Wn≤W<Wn+1, it is just right often to obtain a storage address
The storage value of the address adds 1, is measured and sequentially reads the data of all storage address afterwards and obtain linear pulse width spectra.
A kind of gamma-ray detection system is corresponding with using above-mentioned energy spectrum analysis method comprising receive consolidating for gammaphoton
State semiconductor detector, further includes charge sensitive preamplifier, pole-zero cancellation circuit, quasi- triangle or exponential damping type
Pulse former, the programmable logic chip determined threshold comparator and include counter or timer.Charge-sensitive is preposition
Amplifier carries out integral amplification to the pulsed photocurrent that solid state semiconductor detector exports, it is made to be converted to step pulse signal；
Step pulse signal is converted to exponential decay pulse signal and is amplified to signal amplitude by pole-zero cancellation circuit；Pulse shaping
Exponential decay pulse signal shaping is the pulse signal of finite pulse width by circuit；Determining threshold comparator or trigger will shape
Pulse signal afterwards is converted to the rectangular pulse of respective pulses width；Programmable logic chip measures the pulse width of rectangular pulse
And step-by-step counting, and pulse width spectra is obtained according to a series of corresponding step-by-step counting of pulse widths measured, finally according to arteries and veins
The correspondence of width and impulse amplitude and particle energy is rushed, the pulse amplitude spectrum and power spectrum of gammaphoton can be finally obtained.
The present invention proposes the energy spectrum analysis scheme based on pulse width, using the linearly or nonlinearly manufacturing process of pulse,
Convert impulse amplitude to corresponding pulse width, then pulse-width measures, and the indirect of impulse amplitude is realized with this
It measures.
According to nonlinear amplitude-pulse width conversion method, it is possible, firstly, to using existing pulse shaping technique, because forming
Shape circuit is not required to otherwise designed；Secondly, can in programmable logic chip by digital operational circuit by nonlinear pulse
Width is converted to linear impulse amplitude, and computational accuracy is very high.
According to linear amplitude-pulse width conversion method, first, transformational relation is simple, passes through the design of pulse former
It can be appreciated that can be to avoid Fitting Analysis；Secondly, conversion accuracy is high, since linear circuit is analog circuit and digital circuit
Mainstream, technical maturity is high, and stability is good, it can be achieved that higher accuracy of detection；Again, the threshold range of pulse width is intercepted
It is wider, zero threshold value theoretically may be implemented, which in turns increases the amounts of the precision of pulse width detection and impulse amplitude detection
Journey；Finally, due to eliminate the long problem of nonlinear pulse hangover, pulse width smaller, pulse pile-up problem is opposite to be mitigated, meter
Digit rate can accomplish higher.
The energy spectrum analysis system and gamma-ray detection system of the present invention does not need traditional sampling hold circuit and A/D
Conversion circuit improves circuit response speed to enormously simplify circuit structure, and higher integrated level may be implemented.Pulse
Rectangular pulse after forming not only maintains the amplitude information, threshold information and count information of pulse signal, but also can be with single line
Transmission, thus the extension of port number easy to implement.Since counter or timer are the most basic units of digital circuit, in FPGA
There is a large amount of circuit resource in equal digit chips, thus can efficiently be realized using existing digit chip highly integrated.
Description of the drawings
Fig. 1 is in background technology based on the flow diagram for simulating the quasi- molding energy spectrum analysis system of Gauss；
Fig. 2 is the flow diagram of the energy spectrum analysis system based on digital trapezoidal shaping in background technology；
Fig. 3 is the flow diagram of the energy spectrum analysis system of the present invention；
Fig. 4 is a kind of flow diagram of specific embodiment in energy spectrum analysis system of the present invention；
Fig. 5 is the flow diagram of another specific embodiment in energy spectrum analysis system of the present invention.
Specific implementation mode
The invention will be further described with reference to the accompanying drawings and examples.
The thinking of the present invention is to avoid in the prior art directly measuring impulse amplitude, is thus avoided at a high speed and high-precision
The A/D converter of degree, and change by converting impulse amplitude to pulse width, pulse width is obtained indirectly by measuring pulse width spectra
Degree spectrum.
For particle detector, what is exported after preposition amplification is typically step pulse (including approximate step pulse) letter
Number, this pulse signal is suitble to amplitude detection, but is not suitable for pulse width detection.Therefore it needs to carry out pulse to the pulse signal
Forming is handled, to obtain being suitble to the pulse signal of pulse width detection.Flow diagram such as Fig. 3 of the energy spectrum analysis system of the present invention
It is shown, the prior art is pressed first and receives particle, is converted particle energy to inceptive impulse signal, is then processed into step arteries and veins
Signal Au (t) is rushed, keeps the amplitude A of step pulse signal corresponding with particle energy E.Then it is rectangle arteries and veins by its pulse shaping
Rush signal.During pulse shaping, it is a definite value to make the impulse amplitude of rectangular pulse signal, makes the pulse of rectangular pulse signal
The impulse amplitude A of width W and step pulse signal is in one-to-one relationship.The rectangular pulse signal is actually both simulation letter
Number and digital signal because its pulse width is the analogue value, and impulse amplitude is then digital value (only height divide), because
This, rectangular pulse signal can be directly accessed digital circuit, and pulse width can pass through conventional timer or counter
It measures, passes through the step-by-step counting for analyzing each pulse width, obtain pulse width spectra.And according to rectangular pulse width and step
The correspondence of impulse amplitude, pulse width spectra may finally be converted to pulse amplitude spectrum, or according to rectangular pulse width and
Pulse width spectra is converted directly into the power spectrum of particle by the correspondence of particle energy.
The method that step pulse signal is converted into rectangular pulse signal includes the following steps：
a：By step pulse signal Au (t) by amplifying and forming is converted into shaped pulse signal h (A, t), wherein h
The pulse width and impulse amplitude of (A, t) are non-zero finite value.
b：It converts the shaped pulse signal h (A, t) that step a is obtained to rectangular pulse letter using threshold value comparison method is determined
Number, the impulse amplitude of the rectangular pulse signal is certain value, pulse width W and the step pulse signal of the rectangular pulse signal
Amplitude A is at continuous monotonic functional relationship W=F (A).
Under the thinking of above-mentioned forming method, the following two kinds specific algorithm can be selected to shape.
Algorithm one：Shaped pulse signal has functional form Af (t), and wherein A is the impulse amplitude of step pulse signal,
F (t) is impulse function linearly or nonlinearly, which has non-zero and be limited pulse width and impulse amplitude,
And the rising edge and failing edge on peak value of pulse both sides are respectively continuous monotonic function f1(t) and f2(t).Determine threshold value comparison method
Middle rising edge threshold value is the T of non-zero1, failing edge threshold value is the T of non-zero2, to obtain the width W and step of rectangular pulse signal
The amplitude A of pulse signal is at fixed functional relation
Algorithm two：Shaped pulse signal has functional form f (t/A), and wherein A is the impulse amplitude of step pulse signal, f
(t/A) it is impulse function linearly or nonlinearly, which has non-zero and is limited pulse width and impulse amplitude,
And the rising edge and failing edge on peak value of pulse both sides are respectively continuous monotonic function f1(t/A) and f2(t/A).Determine threshold value comparison
Rising edge threshold value is the T of non-zero in method1, failing edge threshold value is the T of non-zero2, to obtain the width W of rectangular pulse signal with
The amplitude A of step pulse signal is at fixed linear functional relation
In order to shape final rectangular pulse signal, generally require and be first amplified step pulse signal, then at
Shape is that there are the pulse signals of correspondence for impulse amplitude and pulse width, then by comparing device or trigger by shaped pulse
Be converted to the rectangular pulse of respective pulses width.Linear transformation and non-can be substantially divided into according to the transformational relation of amplitude-pulsewidth
Linear transformation two major classes, wherein triangular pulse and trapezoidal pulse are typical linear transformation waveform, and exponential decay pulse and standard
Gaussian pulse is then typical non-linear conversion waveform, it is contemplated that simplicity, substantivity and the high-precision of measurement, preferably by
Amplitude and the linear PULSE SHAPING METHODS FOR HIGH of pulsewidth.For the sake of simplicity, it is declined individually below with triangular pulse forming and index
The gamma ray spectroscopy analysis system for subtracting pulse shaping is illustrated as technology case study on implementation, but the relevant technologies are easily generalized to
Linear and nonlinear pulse width conversion based on other impulse waveforms and pulse width measure system, application are not limited to described specific
Case.
Corresponding above-mentioned energy spectrum analysis method, can obtain a kind of energy spectrum analysis system, and receiving transducer is used for particle energy
Amount is converted into inceptive impulse current signal, further includes preamplifier, pole-zero cancellation circuit, pulse former, determines threshold value
Comparator or trigger and the programmable logic chip for including counter or timer.
Wherein, inceptive impulse signal is that impulse amplitude is corresponding with particle energy by integrating enhanced processing by preamplifier
Step pulse signal；Pole-zero cancellation circuit is used to convert step pulse signal to exponential decay pulse signal and by signal width
Value amplification；Pulse former is for converting exponential decay pulse signal in the forming arteries and veins with certain pulse width and amplitude
Signal is rushed, threshold comparator is determined for converting the shaped pulse signal to rectangular pulse signal, makes the pulse of the rectangular pulse
Amplitude is fixed value, and the pulse width of the rectangular pulse is made to be equal to pulse width of the shaped pulse signal at threshold value；It is programmable
Logic chip is used to measure pulse width and the step-by-step counting of rectangular pulse signal, and a series of pulses obtained according to measurement
Width and corresponding counting are worth to pulse width spectra, can be by arteries and veins finally by the correspondence of pulse width and impulse amplitude
It rushes width spectrum and is converted to pulse amplitude spectrum, or according to the correspondence of pulse width and particle energy directly by pulse width spectra
Be converted to the power spectrum of particle.
Above-mentioned pulse former is using the time domain waveform of the shock response standard three consistent with the impulse waveform after forming
Angle pulse former.But, quasi- triangular pulse forming can also use peak holding circuit combination constant-current charge or electric discharge electricity
The triangular pulse forming of right angle or on-right angle may be implemented in road；Or the logarithm operation pulse amplifying circuit using simulation,
Exponential decay pulse signal is converted to the right angled triangle pulse of linear attenuation by it.
Programmable logic chip carry out pulse width detection process can be：Rectangular pulse signal is touched by D first
Send out device and clock signal synchronization；Then by the rectangular pulse signal after synchronizing and clock signal phase with acquisitions time span is square
The clock signal of shape pulse width；Pulsimeter finally is carried out to the clock signal of the rectangular pulse width duration of acquisition with counter
Number, count value represent the pulse width of rectangular pulse signal.
Programmable logic chip carry out pulse width detection process may be：With rectangular pulse signal control counter
Step-by-step counting is carried out to clock signal, count value represents the pulse width of rectangular pulse signal.
Programmable logic chip carry out step-by-step counting process can be：The pulse width count value of rectangular pulse signal
Storage address is converted to by linear relationship, a storage address is often obtained and 1 just is added to the storage value of the address, be measured rear suitable
The data that sequence reads the memory obtain pulse width spectra.
Programmable logic chip carry out step-by-step counting process may be：According to the pulse width and step of rectangular pulse
The correspondence W=F (A) of the impulse amplitude of pulse presses the pulse width count value of rectangular pulse signal linearly or nonlinearly
Functional relation be segmented Wn=F (An) and An+1=An+ Δ, wherein n are non-negative integer, and Δ is fixed value, makes each section of pulse
Width (Wn≤W<Wn+1As soon as) storage address is corresponded to, it often obtains a storage address and 1 is added to the storage value of the address, measure
The data for sequentially reading the memory after the completion obtain linear pulse width spectra, i.e. pulse width in the pulse width spectra
Impulse amplitude with step pulse is linear relationship.
Programmable logic chip carry out step-by-step counting process can also be：According to the pulse width and step of rectangular pulse
The pulse width count value W of rectangular pulse signal is inverse function operation A by the correspondence W=F (A) of the impulse amplitude of pulse
=F-1(W) impulse amplitude is converted to, impulse amplitude A is then converted into storage address by linear relationship, often obtains a storage
Address just adds 1 to the storage value of the address, is measured and sequentially reads the data of the memory afterwards and obtain pulse amplitude spectrum.
The heterogeneous linear energy spectrum analysis system illustrated the present invention with nonlinear amplitude-pulse width conversion below.
The flow chart of energy spectrum analysis system based on linear triangular pulse forming is as shown in figure 4, it realizes that process is as follows：
a：Particle is received using semiconductor detector, and particle energy is converted to initial pulse current.
b：Initial pulse current is converted to by approximate step pulse signal using charge sensitive preamplifier.
c：Step pulse signal is converted by exponential decay pulse signal, i.e., usually said point using pole-zero cancellation circuit
Pulse signal, the pulsewidth of pulse signal is by compression in the process and amplitude is amplified.
d：Exponential decay pulse is converted using the quasi- triangular pulse wave-shaping circuit that shock response is approximately right angled triangle
For triangular pulse, and the pulse width of triangular pulse and its impulse amplitude are linear.
e：Triangular pulse is converted to by rectangle arteries and veins using the single limit or hysteresis loop comparator of fixed threshold (can be close to zero)
The amplitude of punching, rectangular pulse is standardized digital signal amplitude, and pulse width corresponds to the triangular pulse width at threshold value.
f：Rectangular pulse signal is shaped as by a synchronous rectangular pulse signal using the d type flip flop inside fpga chip,
Rising edge synch of the rising edge and failing edge of the synchronization rectangular pulse with fpga chip internal clocking.
g：Using the AND gate circuit inside fpga chip by synchronous rectangular pulse signal and clock signal phase with, output when
Between length be equal to rectangular pulse width clock pulses.
h：The clock pulses for being equal to rectangular pulse width to duration using the counter inside fpga chip is counted, and is counted
Numerical value is rectangular pulse width.
i：The count value of pulse width is converted to the storage address of fpga chip internal storage, conversion regime is one
(or per adjacent several) pulse width values correspond to a storage address, and storage address with pulse width values sequentially
(or successively decreasing).
j：Detect storage address validity (such as whether being zero), often obtain one effectively storage address just in memory
The storage value of appropriate address carries out plus 1 operation.
k：At the end of time of measuring, the data order stored in memory is read, and storage address is converted into pulse
Width value, you can obtain pulse width spectra.
l：It finally, can be wide by pulse according to the linear relationship of rectangular pulse width and step pulse amplitude and particle energy
Degree spectrum is converted to pulse amplitude spectrum and particle spectrum.
Energy spectrum analysis system based on the forming of nonlinear exponential decay pulse.Flow chart is as shown in figure 5, its principle stream
Journey is as follows：
a：Particle is received using semiconductor detector, and particle energy is converted to initial pulse current.
b：Initial pulse current is converted to by approximate step pulse signal using charge sensitive preamplifier.
c：Step pulse signal is converted by exponential decay pulse signal using pole-zero cancellation circuit, the exponential decay pulse
Time constant be certain value.
d：Exponential decay pulse is converted to by rectangular pulse, square using the single limit or hysteresis loop comparator of fixed threshold (non-zero)
The amplitude of shape pulse is standardized digital signal amplitude, and pulse width corresponds to the exponential decay pulse width at threshold value.
e：The counter that CPLD chip interiors are controlled using rectangular pulse counts clock pulses, gate time length
As rectangular pulse width, thus the count value of counter corresponds to rectangular pulse width.
f：Rectangular pulse width value is converted to the storage address of CPLD chip interior memories, conversion regime is by linear
(or logarithm) mode is segmented pulse width values, and each section of pulse width values correspond to a storage address, and storage address is with arteries and veins
Rush width value sequentially (or successively decreasing).
g：Detect storage address validity (such as whether being zero), often obtain one effectively storage address just in memory
The storage value of appropriate address carries out plus 1 operation.
h：At the end of time of measuring, the data order stored in memory is read, and storage address is pressed into linear mode
It is reconverted into pulse width values, you can obtain pulse width spectra.
i：Finally, right according to the pulse width of exponential decay pulse and the logarithm (or linear) of impulse amplitude and particle energy
It should be related to, pulse width spectra can be converted to pulse amplitude spectrum and particle spectrum.
Above-mentioned energy spectrum analysis method and system is applied in gamma-ray detection system, the solid-state half of gammaphoton is received
Conductor detector, pole-zero cancellation circuit, pulse former, determines threshold comparator and includes meter charge sensitive preamplifier
The programmable logic chip of number device or timer.The pulsed light that charge sensitive preamplifier exports solid state semiconductor detector
Electric current carries out integral amplification, it is made to be converted to step pulse signal.
When pulse former is the linear impulsives wave-shaping circuit such as triangle or trapezoidal pulse wave-shaping circuit, pole-zero cancellation
Step pulse signal is converted to exponential decay pulse signal and is amplified to signal amplitude by circuit, linear impulsive wave-shaping circuit
Exponential decay pulse is configured to linear (waveform) pulse, threshold comparator is determined and linear (waveform) pulse signal is converted into correspondence
The rectangular pulse of pulse width, include counter or timer programmable logic chip measure rectangular pulse pulse width and
Step-by-step counting, and pulse width spectra is obtained according to a series of corresponding step-by-step counting of pulse widths measured, finally according to pulse
The linear relationship of width and impulse amplitude and particle energy can finally obtain the pulse amplitude spectrum and power spectrum of gammaphoton.
When pulse former be the one kind such as exponential decay pulse or quasi- Gaussian particle filter circuit nonlinear pulse at
When shape circuit, step pulse signal is converted to exponential decay pulse signal and is put to signal amplitude by pole-zero cancellation circuit
Greatly, exponential decay pulse is configured to non-linear (waveform) pulse by nonlinear pulse wave-shaping circuit, and determining threshold comparator will be non-thread
Property (waveform) pulse signal is converted to the rectangular pulse of respective pulses width, includes the programmable logic core of counter or timer
Piece measures pulse width and the step-by-step counting of rectangular pulse, by a series of pulse widths measured by nonlinear function mode point
Section so that pulse width is corresponding with linear amplitude, and the step-by-step counting corresponding to each section obtains pulse width spectra, most
Afterwards according to the linear relationship of pulse width and impulse amplitude and particle energy, the pulse amplitude spectrum of gammaphoton can be finally obtained
And power spectrum.
Claims (8)
1. a kind of energy spectrum analysis method includes the steps that converting particle energy to inceptive impulse signal, which is characterized in that also wrap
Include following steps：
1. the inceptive impulse signal is made step pulse signal by integrating enhanced processing as step pulse signal Au (t)
Amplitude A it is corresponding with particle energy E；
2. being converted into rectangular pulse signal after step pulse signal is carried out pulse shaping, make the impulse amplitude of rectangular pulse signal
For a definite value, the impulse amplitude A of the pulse width W for making rectangular pulse signal and step pulse signal is in one-to-one relationship；
3. it measures the pulse width of rectangular pulse signal and step-by-step counting is carried out to rectangular pulse signal, it is a series of according to what is measured
Pulse width and the statistical result of corresponding step-by-step counting obtain pulse width spectra；
4. pulse width spectra is converted to by pulse amplitude spectrum according to the correspondence of rectangular pulse width and step pulse amplitude, or
Pulse width spectra is converted directly into the power spectrum of particle according to the correspondence of rectangular pulse width and particle energy by person；
The step method that 2. middle step pulse signal is converted into rectangular pulse signal includes the following steps：
a：By step pulse signal Au (t) by amplifying and forming is converted into shaped pulse signal h (A, t), wherein h (A, t)
Pulse width and impulse amplitude be limited nonzero value；
b：It converts the shaped pulse signal h (A, t) that step a is obtained to rectangular pulse signal using threshold value comparison method is determined, it should
The impulse amplitude of rectangular pulse signal is certain value, the amplitude A of the pulse width W and step pulse signal of the rectangular pulse signal
At continuous monotonic functional relationship W=F (A)；
Shaped pulse signal in the step a has functional form Af (t), and wherein A is the pulse width of step pulse signal
Degree, f (t) are impulse functions linearly or nonlinearly, which has non-zero and be limited pulse width and pulse width
Degree, and the rising edge on peak value of pulse both sides and failing edge are respectively continuous monotonic function f1(t) and f2(t)；
The step b's determines the T that rising edge threshold value in threshold value comparison method is non-zero1, failing edge threshold value is the T of non-zero2, to obtain
The width W of the rectangular pulse signal and amplitude A of step pulse signal is at fixed functional relation
T indicates the time.
2. a kind of energy spectrum analysis method includes the steps that converting particle energy to inceptive impulse signal, which is characterized in that also wrap
Include following steps：
1. the inceptive impulse signal is made step pulse signal by integrating enhanced processing as step pulse signal Au (t)
Amplitude A it is corresponding with particle energy E；
2. being converted into rectangular pulse signal after step pulse signal is carried out pulse shaping, make the impulse amplitude of rectangular pulse signal
For a definite value, the impulse amplitude A of the pulse width W for making rectangular pulse signal and step pulse signal is in one-to-one relationship；
3. it measures the pulse width of rectangular pulse signal and step-by-step counting is carried out to rectangular pulse signal, it is a series of according to what is measured
Pulse width and the statistical result of corresponding step-by-step counting obtain pulse width spectra；
4. pulse width spectra is converted to by pulse amplitude spectrum according to the correspondence of rectangular pulse width and step pulse amplitude, or
Pulse width spectra is converted directly into the power spectrum of particle according to the correspondence of rectangular pulse width and particle energy by person；
The step method that 2. middle step pulse signal is converted into rectangular pulse signal includes the following steps：
a：By step pulse signal Au (t) by amplifying and forming is converted into shaped pulse signal h (A, t), wherein h (A, t)
Pulse width and impulse amplitude be limited nonzero value；
b：It converts the shaped pulse signal h (A, t) that step a is obtained to rectangular pulse signal using threshold value comparison method is determined, it should
The impulse amplitude of rectangular pulse signal is certain value, the amplitude A of the pulse width W and step pulse signal of the rectangular pulse signal
At continuous monotonic functional relationship W=F (A)；
Shaped pulse signal in the step a has functional form f (t/A), and wherein A is the pulse width of step pulse signal
Degree, f (t/A) are impulse functions linearly or nonlinearly, which has non-zero and be limited pulse width and pulse
Amplitude, and the rising edge on peak value of pulse both sides and failing edge are respectively continuous monotonic function f1(t/A) and f2(t/A)；
The rising edge threshold value in threshold value comparison method of determining of the step b is T1, failing edge threshold value is T2, to obtain rectangular pulse
The width W of the signal and amplitude A of step pulse signal is at fixed linear functional relation
T indicates the time.
3. a kind of energy spectrum analysis method according to claim 1 or 2, it is characterised in that：The shaped pulse signal is line
Property triangular pulse signal or trapezoidal pulse signal, or believe for nonlinear exponential decay pulse signal or quasi- Gaussian pulse
Number.
4. a kind of energy spectrum analysis system for realizing claims 1 or 2 the method includes the receiving transducer of conversion particle energy,
Receiving transducer is used to convert particle energy to inceptive impulse current signal, it is characterised in that：Further include preamplifier, pole zero
Cancellation circuit, pulse former, the programmable logic chip determined threshold comparator and include counter or timer；
Wherein, inceptive impulse signal is impulse amplitude rank corresponding with particle energy by integrating enhanced processing by preamplifier
Jump pulse signal；Pole-zero cancellation circuit is for converting step pulse signal to exponential decay pulse signal and putting signal amplitude
Greatly；Pulse former is used to convert exponential decay pulse signal to be believed with the shaped pulse of certain pulse width and amplitude
Number, determine threshold comparator or trigger is used to convert the shaped pulse signal to rectangular pulse signal, makes the rectangular pulse
Impulse amplitude is fixed value, and the pulse width of the rectangular pulse is made to be equal to pulse width of the shaped pulse signal at threshold value；It can
Programmed logic chip is used to measure pulse width and the step-by-step counting of rectangular pulse signal, and according to measure obtained it is a series of
Pulse width and corresponding counting are worth to pulse width spectra, can be with finally by the correspondence of pulse width and impulse amplitude
Pulse width spectra is converted into pulse amplitude spectrum, or directly that pulse is wide according to the correspondence of pulse width and particle energy
Degree spectrum is converted to the power spectrum of particle.
5. energy spectrum analysis system according to claim 4, it is characterised in that：The pulse former uses shock response
The time domain waveform quasi- triangular pulse wave-shaping circuit consistent with the impulse waveform after forming.
6. a kind of energy spectrum analysis system according to claim 5, it is characterised in that：The quasi- triangular pulse wave-shaping circuit is adopted
With the logarithm operation pulse amplifying circuit of simulation, exponential decay pulse signal is converted to the right angled triangle arteries and veins of linear attenuation
Punching.
7. a kind of energy spectrum analysis system according to claim 4, it is characterised in that：
Programmable logic chip carry out pulse width detection process be：First by rectangular pulse signal by d type flip flop and when
Clock signal synchronizes；Then step-by-step counting is carried out to clock signal with rectangular pulse signal control counter, then count value represents square
The pulse width of shaped pulse signal；
Programmable logic chip carry out step-by-step counting process be：According to the pulse of the pulse width of rectangular pulse and step pulse
The pulse width count value of rectangular pulse signal is pressed functional relation linearly or nonlinearly by the correspondence W=F (A) of amplitude
It is segmented Wn=F (An) and An+1=An+ Δ, wherein n are non-negative integer, and Δ is fixed value, and each section of pulse width W is made to correspond to one
A storage address, wherein Wn≤ W ＜ Wn+1, often obtain a storage address and 1 just added to the storage value of the address, after being measured
The data that sequence reads all storage address obtain linear pulse width spectra.
8. a kind of gamma-ray detection system based on linear pulse width measure using 2 the method for claims 1 or 2, including connect
Receive the solid state semiconductor detector of gammaphoton, it is characterised in that：Further include charge sensitive preamplifier, pole-zero cancellation electricity
Road, quasi- triangle or exponential damping type pulse former, determine threshold comparator and include counter or timer can
Programmed logic chip；
Charge sensitive preamplifier carries out integral amplification to the pulsed photocurrent that solid state semiconductor detector exports, and makes its conversion
For step pulse signal；Pole-zero cancellation circuit by step pulse signal be converted to exponential decay pulse signal and to signal amplitude into
Row amplification；Exponential decay pulse signal shaping is the pulse signal of finite pulse width by pulse former；Determine threshold value comparison
Pulse signal after forming is converted to the rectangular pulse of respective pulses width by device or trigger；Programmable logic chip measures square
The pulse width of shape pulse and step-by-step counting, and it is wide according to a series of corresponding step-by-step counting of pulse widths measured to obtain pulse
Degree spectrum, finally according to the correspondence of pulse width and impulse amplitude and particle energy, can finally obtain the arteries and veins of gammaphoton
Rush amplitude spectrum and power spectrum.
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| CN110308476B (en) * | 2019-07-31 | 2021-01-08 | 北京大学 | Particle radiation detection method and detection device |
| CN110609050B (en) * | 2019-09-25 | 2021-05-25 | 成都理工大学 | Method and system for eliminating X-ray fluorescence spectrum peak tailing |
| CN112327347B (en) * | 2020-10-29 | 2022-11-18 | 中广核久源（成都）科技有限公司 | Digital nuclear pulse forming system with adjustable curvature |
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