CN107272049B - Digital n- γ discriminating method based on pulse width - Google Patents

Digital n- γ discriminating method based on pulse width Download PDF

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CN107272049B
CN107272049B CN201710569098.6A CN201710569098A CN107272049B CN 107272049 B CN107272049 B CN 107272049B CN 201710569098 A CN201710569098 A CN 201710569098A CN 107272049 B CN107272049 B CN 107272049B
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point
digital waveform
amplitude
pulse
4n
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CN201710569098.6A
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CN107272049A (en
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王琦标
庹先国
邓超
沈统
李怀良
冷阳春
石睿
李金夫
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成都理工大学
四川理工学院
西南科技大学
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Abstract

The invention discloses a kind of digital n- γ discriminating method based on pulse width, comprising: carried out using detector and capture card from trigger-type digital waveform S in mixed radiation fieldnIt samples and stores;Digital waveform S will be samplednCubic spline interpolation processing is carried out, the digital waveform S of 4 sampling points is obtained4n;Digital waveform S4nIt is handled through First derivative spectrograply, obtains digital waveform S4nPeak point P and peak value Vp;Calculate maximum white noise VnWith activation threshold value VTRatio R, and also be pulse start-stop point amplitude VsWith peak value VpRatio;Using ratio R, counter push away obtains start-stop point amplitude Vs, and determine the starting point K and cut off Q of pulse;Width between starting point K and cut off Q is pulse width W, obtains n- γ using pulse width W and screens result.The discriminating method, which has many advantages, such as that calculating is easy, excludes subjective parameters setting, to be influenced, it is accurate to screen, in radiation detection technology field with very high practical value and promotional value.

Description

Digital n- γ discriminating method based on pulse width

Technical field

The present invention relates to radiation detection technology fields, and in particular to the digital n- γ discriminating method based on pulse width.

Background technique

Since neutron discovery, it has been widely used in radiation detection field.In mixed radiation field, gamma-rays and neutron It is also most important two kinds of rays that n, which is most common in radiation field, also the same in the occasion of neutron since two kinds of rays are not charged With the presence of gamma-rays, neutron detector is also sensitive to gamma-rays, and gamma ray detector can be to neutron-sensitive.Therefore, n- γ is screened Technology is to improve single radionetric survey precision in mixed radiation field, reduces one of the key of neutron (or gamma-rays) background.

N- γ examination is when generating different charged particles in detector using neutron and gamma-rays to cause different decaying Between speed component ratio, to the difference of impulse waveform occur.Currently, the most common number n- γ discriminating method is that charge compares Method screens incoming particle by fast component (or slow component) charge of impulse waveform and the proportional difference of total electrical charge, and this method is not Foot place be, need specify 3 parameter calculated charge ratios, i.e., total electrical charge integral starting point, total electrical charge integral cut off and Fast component charge integration cut off (or slow composition charge integration starting point), these three parameters directly determine the quality that n- γ is screened The factor.Due to the specified not stringent reference standard of these three parameters, needs repeatedly to optimize determination according to quality factor, lead Cause calculating process cumbersome, and the quality factor that n- γ is screened is larger by subjective impact.

Patent publication No. be CN201620788584.8 Chinese patent disclose it is a kind of digitize neutron spectrometer neutron, γ discrimination system, uses pulse fall time to screen algorithm, and pulse signal peak atenuation is discriminated to different proportion time difference Δ t Other neutron and gamma-rays are artificially set by setting the one-to-one correspondence mapping relations of maximum value X% and maximum value Y% time difference Fixed maximum value X% and maximum value Y% is changing value, and optimal value could be obtained by needing to carry out repeatedly calculation optimization.This method The calculating process for the quality factor that optimization n- γ is screened is simplified to a certain extent, but two parameters set are without stringent ginseng Standard is examined, still needs to optimize calculating, it is cumbersome there is no solving the problems, such as to calculate.

To sum up, it is necessary to n- γ screening techniques be proposed to improve, to obtain easy discriminating method.

Summary of the invention

The purpose of the present invention is to provide a kind of digital n- γ discriminating method based on pulse width, mainly solves existing skill Examination algorithm present in art specifies parameter more, and calculating is complex, and quality factor optimization process is biggish by subjective impact Problem.

To achieve the goals above, The technical solution adopted by the invention is as follows:

Digital n- γ discriminating method based on pulse width, is mainly resulted in using the die-away time difference of different particles Corresponding pulses decay to required time difference when identical amplitude proportion, and it is wide that this difference can intuitively be embodied in pulse On degree.Therefore n- γ examination can effectively be carried out according to pulse width, the specific steps are as follows:

Step 1: being carried out using detector and capture card from trigger-type digital waveform S in mixed radiation fieldnSampling is simultaneously Storage, digital waveform SnFor activation threshold value VTPreceding m point and activation threshold value VTN-m point afterwards, wherein m is greater than 0, n and is greater than m.

Step 2: digital waveform S will be samplednCubic spline interpolation processing is carried out, the digital waveform of 4 sampling points is obtained S4n

Step 3: digital waveform S4nIt is handled through First derivative spectrograply, obtains digital waveform S4nPeak point P and peak value Vp

Step 4: by digital waveform S4nPreceding 2m point maximum amplitude as maximum white noise Vn

Step 5: calculating maximum white noise VnWith activation threshold value VTRatio R, and R is also pulse start-stop point amplitude VsWith peak Value VpRatio.

Step 6: counter push away obtains pulse start-stop point amplitude V using ratio Rs, and determine the starting point K and cut off of pulse Q, the specific steps are as follows:

(1) from digital waveform S4nPeak point P be moved to the left point by point, and successively with pulse start-stop point amplitude VsCompare, if Starting point amplitude VK≤ pulse start-stop point amplitude VsWhen, then K point is starting point, otherwise continues to compare to the left;

(2) from digital waveform S4nPeak point P move right point by point, and successively with pulse start-stop point amplitude VsCompare, if Cut off amplitude VQ≤ pulse start-stop point amplitude VsWhen, then Q point is cut off, otherwise continues to compare to the right.

Wherein, the width between starting point K and cut off Q is pulse width W.

Finally, being distributed using the pulse width W, obtains n- γ and screen result.

Compared with prior art, the invention has the following advantages:

(1) present invention is in such a way that detector and capture card trigger digit pulse wave, by the digit pulse wave of generation into The processing of row cubic spline interpolation, only sets a parameter on waveform, i.e., maximum white noise VnWith activation threshold value VTRatio R, In, activation threshold value VTTo determine parameter when impulse waveform use, ratio R only with maximum white noise VnIt is related, arbitrary point amplitude and arteries and veins Rush start-stop point amplitude VsComparison obtains pulse width W, using pulse width to realize that n- γ is screened, simplifies cumbersome parameter The calculating process of optimization.

(2) moreover, pulse start-stop point amplitude VsWith peak VpValue ratio R only by the maximum white noise of sample waveform and touching It sends out threshold value and determines that quality factor are poor caused by can effectively avoid because of subjective factor, n- γ examination is impacted.

(3) present invention is using easy discriminating method, the result screened compared with the Charge comparison method of existing maturation, The peak value of two kinds of particles can be more differentiated, and screens that process is more simple, and quality factor are not influenced by subjective setup parameter, the party Method, which has many advantages, such as that calculating is easy, excludes subjective parameters setting, to be influenced, it is accurate to screen, in radiation detection technology field with very high Practical value and promotional value.

Detailed description of the invention

Fig. 1 is the schematic diagram of the digital n- γ discriminating method based on pulse width.

Fig. 2 is the flow chart of the digital n- γ discriminating method based on pulse width.

Fig. 3 is that the hangover integral charge of Charge comparison method and total mark charge compare distribution map.

Fig. 4 is the charge that is obtained using Charge comparison method than the 2D distribution map with pulse amplitude

Fig. 5 is the pulse width distribution map of the digital n- γ discriminating method based on pulse width.

Fig. 6 is the pulse width of the digital n- γ discriminating method based on pulse width and the 2D distribution map of pulse amplitude.

Specific embodiment

Present invention will be further explained below with reference to the attached drawings and examples, and embodiments of the present invention include but is not limited to The following example.

Embodiment

As shown in Figure 1, neutron pulse waveform S1 and gamma-ray burst waveform S2 decay to it is corresponding when identical amplitude proportion Time point is different, i.e. time t' and time t, the difference of different particle die-away times are intuitively embodied on pulse width W, according to The difference of pulse width W can effectively carry out n- γ examination.

As shown in Fig. 2, the digital n- γ discriminating method based on pulse width, discriminating method include the following steps:

Step 1: being carried out using detector and capture card from trigger-type digital waveform S in mixed radiation fieldnSampling is simultaneously Storage, digital waveform SnFor activation threshold value VTPreceding m point and activation threshold value VTN-m point afterwards, wherein m is greater than 0, n and is greater than m.

Step 2: digital waveform S will be samplednCubic spline interpolation processing is carried out, the digital waveform of 4 sampling points is obtained S4n

Step 3: digital waveform S4nIt is handled through First derivative spectrograply, obtains digital waveform S4nPeak point P and peak value Vp

Step 4: by digital waveform S4nPreceding 2m point maximum amplitude as maximum white noise Vn

Step 5: calculating maximum white noise VnWith activation threshold value VTRatio R, and R is also pulse start-stop point amplitude VsWith peak Value VpRatio.

Step 6: counter push away obtains pulse start-stop point amplitude V using ratio Rs, and determine the starting point K and cut off of pulse Q, the specific steps are as follows:

(1) from digital waveform S4nPeak point P be moved to the left point by point, and successively with pulse start-stop point amplitude VsCompare, if Starting point amplitude VK≤ pulse start-stop point amplitude VsWhen, then K point is starting point, otherwise continues to compare to the left;

(2) from digital waveform S4nPeak point P move right point by point, and successively with pulse start-stop point amplitude VsCompare, if Cut off amplitude VQ≤ pulse start-stop point amplitude VsWhen, then Q point is cut off, otherwise continues to compare to the right.

Wherein, the width between starting point K and cut off Q is pulse width W.

Finally, being distributed using the pulse width W, obtains n- γ and screen result.

Experimental data use EJ299-33A detector electron energy on the phot-neutron source of 7MeV by 2.5Gs/s's Digital oscilloscope sampling measures.Wherein, the hangover integral charge and total mark charge that Fig. 3 is Charge comparison method are than distribution map, Fig. 5 For pulse width distribution map of the invention, Fig. 4 is the charge that is obtained using Charge comparison method than the 2D distribution map with pulse amplitude, Fig. 6 is the 2D distribution map using pulse width and pulse amplitude of the invention, can be seen that the method for the present invention more from comparison diagram The peak value of two kinds of particles can be differentiated, n- γ examination quality factor are higher, it is more easy to screen process, and quality factor are not by subjectivity Setup parameter influences.

Above-described embodiment is merely a preferred embodiment of the present invention, and it is not intended to limit the protection scope of the present invention, as long as using Design principle of the invention, and the non-creative variation worked and made is carried out on this basis, it should belong to of the invention Within protection scope.

Claims (1)

1. the digital n- γ discriminating method based on pulse width, which comprises the steps of:
(I) it in mixed radiation field, is carried out using detector and capture card from trigger-type digital waveform SnIt samples and stores;It is described Digital waveform SnFor activation threshold value VTPreceding m point and activation threshold value VTN-m point afterwards, wherein m is greater than 0, n and is greater than m;
(II) by the sampling digital waveform SnCubic spline interpolation processing is carried out, the digital waveform S of 4 sampling points is obtained4n
(III) the digital waveform S4nIt is handled through First derivative spectrograply, obtains digital waveform S4nPeak point P and peak value Vp
(IV) by digital waveform S4nPreceding 2m point maximum amplitude as maximum white noise Vn
(V) setup algorithm maximum white noise VnWith activation threshold value VTRatio R, and R is also pulse start-stop point amplitude VsWith peak value Vp Ratio;
(VI) ratio R is utilized, counter push away obtains pulse start-stop point amplitude Vs, and determine the starting point K and cut off Q of pulse, from Digital waveform S4nPeak point P be moved to the left point by point, and successively with pulse start-stop point amplitude VsCompare, if starting point amplitude VK≤ Pulse start-stop point amplitude VsWhen, then K point is starting point, otherwise continues to compare to the left, from digital waveform S4nPeak point P point by point to Move right, and successively with start-stop point amplitude VsCompare, if cut off amplitude VQ≤ pulse start-stop point amplitude VsWhen, then Q point is cut-off Otherwise point continues to compare to the right;Width between the starting point K and the cut off Q is pulse width W;
(VII) it is distributed using the pulse width W, obtains n- γ and screen result.
CN201710569098.6A 2017-07-13 2017-07-13 Digital n- γ discriminating method based on pulse width CN107272049B (en)

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CN108627867A (en) * 2018-03-14 2018-10-09 中国人民解放军火箭军工程大学 A kind of real-time discrimination systems of digitlization n- γ
CN108490477A (en) * 2018-03-14 2018-09-04 中国人民解放军火箭军工程大学 A kind of n- γ pulses discriminating methods and system based on improvement centroid algorithm

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