CN103336293B - A kind of method optimizing liquid scintillation bulk detector examination neutron and gamma ability - Google Patents
A kind of method optimizing liquid scintillation bulk detector examination neutron and gamma ability Download PDFInfo
- Publication number
- CN103336293B CN103336293B CN201310214857.9A CN201310214857A CN103336293B CN 103336293 B CN103336293 B CN 103336293B CN 201310214857 A CN201310214857 A CN 201310214857A CN 103336293 B CN103336293 B CN 103336293B
- Authority
- CN
- China
- Prior art keywords
- signal
- photomultiplier
- detector
- photon
- neutron
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Abstract
The present invention relates to a kind of method optimizing liquid scintillation bulk detector examination neutron and gamma ability, belong to Particel Detection Methods field.The method is first by Monte-carlo Simulation particle photon production process in time in liquid scintillator, then obtains the output signal of single photon at photomultiplier by single photon experiment; The photon sequence that produces of random selecting simulation and single photon are in the output signal convolution of photomultiplier again, to realize the actualization of light signal.By the overall process of simulated light pulse at photomultiplier, obtain a kind of liquid scintillation bulk detector and can assess in the design phase ability that different liquid dodges detector examination neutron and gamma; The parameter of dodging detector by changing designed liquid optimizes designed liquid sudden strain of a muscle detector, and then improves its speed of screening neutron and gamma and precision.
Description
Technical field
The present invention relates to the technology that a kind of detector screens neutron and gamma, particularly a kind of liquid scintillation bulk detector of optimizing improves the method that it screens neutron and gamma ray ability, belongs to Particel Detection Methods field.
Background technology
1931, English physicist James Chadwick found through experiments the existence of neutron (n).After this, between decades, neutron detection technology obtains extensive and deep investigation and application.Current, neutron detection technology has been widely used in the fields such as well logging, contraband detecting, environmental radiation detection, medical science and military affairs.But, due to the reason such as radiative capture of the inelastic scattering in neutron and surrounding environment, degraded neutron, there is the occasion of neutron nearly all along with a large amount of gamma (γ) ray background.And many neutron detectors are also very sensitive to gamma ray, therefore in order to get rid of gamma-ray interference, neutron and gamma discrimination just become a gordian technique of neutron detection.
Performance is screened because liquid scintillation bulk detector has good characteristic sum neutron/gamma (n/ γ) ray time response, and be easy to be prepared into various shape and size, be therefore suitable for the neutron detection in neutron/gamma (n/ γ) mixing field.Neutron and gamma-ray photon, all in electric neutrality, can be detected by producing secondary charged particle with liquid scintillator effect.For liquid scintillation bulk detector, the development of neutron and gamma discriminating method adapts with the development of electron device and signal processing technology.
At present, in analog signal processing method prevailing period, traditional neutron and gamma discriminating method mainly adopt method pulse rise time, Charge comparison method etc. all based on analogue technique.But these have realizing circuit complexity based on the method for analogue technique, the defect such as low and poor stability of pulse percent of pass.In recent years, along with increasing substantially of digital signal processor (DSP) processing speed, the appearance of high-speed AD converter (ADC), the high speed development of field programmable gate array (FPGA), neutron and gamma discriminating method are just towards the future development of digitized signal disposal route.For this reason, Chinese scholars proposes the discriminating method based on Digital Signal Processing such as neural network, pulsed gradient method (PGA), Wavelet Transform, correlation method, substantially increases the ability of neutron and gamma examination thus.And the digitalized processing method such as pulsed gradient method (PGA), neural network and Wavelet Transform, filtering is shaping, the function such as baseline restorer, pole-zero compensation and pulse amplitude analysis to utilize the digital signal processors such as high-speed AD converter (ADC), digital signal processor (DSP), field programmable gate array (FPGA) to complete.It eliminates a large amount of hardware components compared with analog signal processing method, and greatly can improve speed and the precision of neutron and gamma examination; But generally can obtain satisfied result with analog signal processing method.Then more targeted based on digitized signal disposal route, such as wavelet transformation discriminating method has higher frequency resolution and lower time sense in low frequency part, and just in time contrary at HFS, there is higher time sense and lower frequency resolution.The present invention considers based on this point just, in conjunction with the advantage of analog signal processing method and digitized signal disposal route, by optimizing designed liquid scintillation bulk detector to the actualization of particle overall process in liquid scintillation bulk detector, improve to reach a kind of method that it screens neutron and gamma ray ability.
Summary of the invention
Object of the present invention is exactly based on above-mentioned consideration, proposes a kind of liquid scintillation bulk detector of optimization to improve the method that it screens neutron and gamma ray ability.The method is first by Monte-carlo Simulation particle photon production process in time in liquid scintillator; Then the output signal of single photon at photomultiplier is obtained by single photon experiment; The photon sequence that produces of random selecting simulation and single photon are in the output signal convolution of photomultiplier again, to realize the actualization of light signal.By the overall process of simulated light pulse at photomultiplier, obtain a kind of liquid scintillation bulk detector and can assess in the design phase ability that different liquid dodges detector examination neutron and gamma; The parameter of dodging detector by changing designed liquid optimizes designed liquid sudden strain of a muscle detector, and then improves its speed of screening neutron and gamma and precision.
For achieving the above object, the present invention adopts the technical scheme be made up of following technical measures to realize.
A kind of liquid scintillation bulk detector of optimizing that the present invention proposes, to improve the method that it screens neutron and gamma ability, comprises following operation steps:
(1) Monte Carlo light signal is simulated
A) software Geant 4 model fluid scintillator detector is used;
B) generation of software Geant4 simulated photons is used;
(2) single photon experiment:
A) connect and debug instrument;
B) measure and observe the undesired signal that photomultiplier thermonoise and light leak produce;
Not luminous at light emitting diode, and collection signal under wrapping gobo situation, then undesired signal is obtained after the selection of shading treatment and threshold value;
C) input drive signal, measures the signal of photomultiplier;
D) single photoelectron data are gathered;
Adjustment light emitting diode luminance brightness, makes it decay, and when the change of photomultiplier amplitude output signal is little, gathers single photoelectron data;
E) data analysis;
Process matching is carried out to the single photoelectron data gathered and obtains single photon impulse response function;
(3) convolution of signal
A) get a little to single photon impulse response function;
B) use software Matlab to described step a) in taken point carry out interpolation and obtain single photon response function, choose and the point at the light signal same time interval that photon produces in time in liquid scintillation bulk detector described in step (1);
C) get light signal convolution in software Matlab that in single photon impulse response function and model fluid scintillator detector, photon produces in time at random, and the signal obtained with real particles respectively compares.
In technique scheme, step (1) a) described in model fluid scintillator detector, its concrete practice first arranges designed liquid scintillator detector size, form parameter, uses software Geant 4 to simulate and size described in designed liquid scintillation bulk detector, detector that shape is identical.
In technique scheme, step (1) b) described in the generation of simulated photons, its concrete practice arranges following parameter:
(I) arranges photon number, resolution, energy value, speed time parameter; According to liquid scintillation volume property used, " scintillator speed time parameter is than arranging " arranges required photon number, the resolution of scintillator, energy value, speed time parameter in simulation process;
(II) arranges border between photomultiplier and photoconduction and parameter thereof; Border experimentally between room condition setting photomultiplier and photoconduction is dielectric metal, and arranges its reflectivity, efficiency parameters; Obtain the Monte Carlo light signal that particle is simulated in liquid scintillator, be the point of series of equivalent time interval.
In technique scheme, step (2) a) described in debug each instrument used, its concrete practice is:
(I) debugs the drive singal of chronotron used, sets the frequency of described drive singal, width;
(II) makes camera bellows, optical attenuator, shielding external interference;
(III) sets high pressure used, is observed the signal output waveform of photomultiplier by oscillograph.
In technique scheme, step (2) c) described in measure the light signal of photomultiplier, its concrete practice is:
The drive singal of (I) opening time-delaying device, arranges frequency, high pressure used, is observed the signal output waveform of photomultiplier by oscillograph;
(II) changes the luminance brightness inciding photomultiplier by optical attenuation, the change of photomultiplier signal output waveform in observation oscilloscope;
(III) analyzes the impact of optical attenuation on signal.
In technique scheme, in step (3) a) described in get a little to single photon impulse response function, its concrete practice is:
(I) carries out described point and record by software digitizer to the single photon impulse response function image obtained in step (2);
(II) by the described point obtained in software Matlab by outside error, the point that obviously do not belong to single photon signal rejects.
In technique scheme, step (3) b) described in liquid scintillation bulk detector photon produce the point at signal same time interval in time, completed by step below:
(I) utilizes software Matlab method of interpolation fitting function;
(II) utilizes software Matlab to choose and the point at the signal same time interval that photon produces in time in liquid scintillation bulk detector.
Institute of the present invention tool has the following advantages and useful technique effect:
1, a kind of method optimizing liquid scintillation bulk detector examination neutron and gamma ray ability of the present invention, namely the ability that n/ γ screened by this detector can be assessed exactly, to be convenient to the liquid scintillation bulk detector doing ability neutron/gamma examination before making liquid scintillation bulk detector.
2, method of the present invention is simple, convenient, easy to implement, and applicability is wide, the liquid scintillation bulk detector that can be applied to any model.
3, because the inventive method just can be assessed the ability that it screens neutron and gamma before making liquid scintillation bulk detector, thus carry out optimal design liquid scintillation bulk detector by changing the designed parameter such as liquid scintillator detector size, shape, to improve it to the speed of n/ gamma-rays examination and precision.
Accompanying drawing explanation
The liquid scintillator panel detector structure schematic diagram that Fig. 1 the present invention simulates with software Geant4;
The particle of Fig. 2 the present invention simulation throws the structural representation in Fig. 1 into;
The photon of neutron in liquid scintillator of Fig. 3 the present invention simulation; Its horizontal ordinate is the time, and unit is 20ns; Ordinate is counting, and unit is individual;
The photon of gamma in liquid scintillator of Fig. 4 the present invention simulation; Its horizontal ordinate is the time, and unit is 20ns; Ordinate is counting, and unit is individual;
Fig. 5 the present invention single photon experimental circuit used structured flowchart;
The photomultiplier tube signal oscillogram that Fig. 6 the present invention is produced by the drive singal manually arranged;
The undesired signal figure that Fig. 7 photomultiplier thermonoise of the present invention and light leak produce;
The impact that Fig. 8 optical attenuation of the present invention outputs signal photomultiplier;
Schematic diagram is intercepted when Fig. 9 the present invention adopts Plot digitizer software described point to sample;
Figure 10 single photon signal figure of the present invention; Its horizontal ordinate is number of channels; Ordinate is counting;
Figure 11 photomultiplier single photon of the present invention spectrogram;
The contrast of Figure 12 neutron of the present invention and gamma convolution signal and actual signal, wherein (a) simulates gamma and true gamma ray comparison diagram; (b) simulation neutron and true neutron ray comparison diagram; (c) true gamma and true neutron ray comparison diagram; (d) simulation gamma and simulation neutron ray comparison diagram.
In figure, 1 is organic glass, and 2 is photoconduction, 3 is radioactive source, 4 particle sent for simulation signal generator and scattering particles, and 5 is part secondary, 6 is lead brick, and 7 is liquid scintillation bulk detector, and 8 is chronotron, 9 is fan-in fan-out plug-in unit, and 10 is camera bellows, and 11 is light emitting diode, 12 is photomultiplier, 13 put plug-in unit before fast, and 14 is quick digital-to-analog conversion plug-in unit, and 15 is oscillograph.
Embodiment
Below by embodiment, description concrete is further carried out to the present invention; what be necessary to herein means out is that the present embodiment is only for being further described invention; but any restriction that should not be understood as scope, the person skilled in the art in this field can do some nonessential improvement and adjustment according to the content of the invention described above.
Figure 1 shows that model fluid scintillator detector structural representation: its central cylindrical portion material is the organic glass 1 that 4mm is thick, two ends symmetric part is photoconduction 2, photoconduction 2 connects photomultiplier 12 both-end and meets read output signal, organic glass 1 is coupled with photoconduction 2 and between photoconduction 2 with photomultiplier 12 by silicone grease, to increase the collection efficiency of light.
Figure 2 shows that simulation particle throws the schematic diagram of liquid scintillation bulk detector into: wherein contain radioactive source 3, the particle that simulation signal generator sends and scattering particle 4, part secondary 5, lead brick 6, liquid scintillation bulk detector 7.
Single photon experimental circuit block diagram shown in Fig. 5, each instrument plug-in unit is by this experiment block diagram exact connect ion.Its experimentation is the drive singal of first manual adjustments chronotron 8, it is made up of two-way time delayed signal, one tunnel is used for the width of regulating impulse, another road is used for regulating the width between every two pulses and regulating impulse frequency, and end (end) termination of every road signal enters the triggering of beginning (start) end as another road on another road.Just sustainablely after manually starting provide drive singal, realize the function of similar pulse producer, unlike distinguishing regulating impulse frequency and pulse width here, the General Requirements signal period is much larger than pulse width; Can regulating impulse frequency eaily by the observation of oscillograph 15, chronotron 8 provides the square-wave signal of standard NIM signal and 800mV here; Setting its frequency is 2000Hz, and width is 35ns.
Camera bellows 10 used in experiment can form by airtight common cardboard cartons by small one and large one two.Little carton for installing photomultiplier 12, and photomultiplier 12 accept illumination penetrate one side carton on cut a hole, light emitting diode 11 is fixed in the middle of hole, for accepting the light that light emitting diode 11 sends.Certainly, in order to meet the requirement of single photoelectron experiment, need to decay to the light of light emitting diode 11, here common A4 printer paper doubling 4 times are used, one side sticks friction tape, another side subtend photomultiplier 12, light emitting diode 11 can be clipped in the middle selection thickness, reaches the effect of optical attenuation.During experiment, little carton is wrapped up two-layer gobo, be placed in large carton, then by large carton outer wrapping one deck gobo, so then can reach the effect of shielding ambient light interference, reduce experiment background.
The negative high voltage of photomultiplier 12 used is provided by NIM case, is connected on photomultiplier 12 photocathode, is chosen to be-1100V.
Below the output signal of embodiment simulation n/ γ under the instrument appointed condition of laboratory.
The EJ335 scintillator that the R5912-02 type photomultiplier that photomultiplier 12 used is Japanese Bin Song companies, scintillator are Japanese Bin Song companies;
High-voltage power supply N1470 used, negative high voltage power source NIM case; Put plug-in unit 13 before fast and adopt N978; Time delay plug-in unit and chronotron 8 adopt N93B; Fan-in fan-out plug-in unit 9 adopts N65 (FIFO), to be FADCY1721, RIGO be oscillograph 15 to Fast Modular number conversion plug-in unit 14; Light emitting diode 11 i.e. LED, the physical process, the software Matlab for convolution, the software Plot digitizer for described point that use existing software Geant 4 simulation particle to transport in material.
Embodiment
The present embodiment instrument appointed condition is described above, concrete operation step and implementation as follows:
(1) Monte Carlo light signal is simulated
A) utilization software Geant 4 model fluid scintillator detector is installed on computers
First setting designed its diameter of liquid scintillation bulk detector is 30cm, the long cylindrical detector for 40cm, uses software Geant 4 to simulate the liquid scintillation bulk detector identical with its size and dimension;
B) generation of using software Geant 4 simulated photons is installed on computers;
This time that simulation is liquid scintillator EJ331, wherein add the gadolinium that mass ratio is 0.5%, ability is captured with what improve neutron, according to the character of liquid scintillator used, parameter required in setting simulation process: the photon number that in liquid scintillator, unit energy produces is 11000./MeV, the mean fluctuation producing photon obeys a Gaussian distribution, and its resolution is set to 1.0, and the luminous speed in liquid scintillator, luminescence decay time constant are set to 3.8ns and 24.9ns;
Because the luminescence of liquid scintillator is relevant with particle types, when fast slow component being changed by particle types difference, it can be the scitillation process call method " scintillator speed time parameter is than arranging " (SetScintillationExcitationRatio) of every class particle, it arranges different fast slow components by for the luminescence of different particles, the speed time ratio of neutron is 0.752, and the speed time ratio of gamma is 0.799;
Border between photomultiplier 12 and photoconduction 2 is set to dielectric metal, arranging its reflectivity is 0, efficiency is 1, the photon then inciding photoelectric surface can be absorbed completely, obtain neutron, Monte Carlo light signal that gamma is simulated in liquid scintillator is respectively shown in Fig. 3 and Fig. 4, be the point of series of equivalent time interval.
(2) single photon experiment
A) connect and debug instrument;
According to connect shown in Fig. 5 and after having debugged each instrument, regulate time delayed signal, just observe by oscillograph 15 signal that photomultiplier 12 sends, due to be by chronotron 8 trigger light emitting diode 11 for LED luminous, and detect light signal by photomultiplier 12, so light signal all certain hour time delay appearance after the square-wave signal driven, one of them signal is chosen as shown in Figure 6 with oscillograph 15, square-wave signal is the said standard NIM signal as driving above, and another one signal is the signal output waveform of photomultiplier;
B) measure and observe the undesired signal that photomultiplier thermonoise and light leak produce;
Open NIM case, when not producing drive singal, LED is not luminous, now photomultiplier 12 is added to the high pressure of-1100V, some signals not having rule, amplitude not of uniform size that oscillograph 15 can be seen, these are the undesired signals because the thermonoise of photomultiplier and light leak produce; After having added gobo, can see that the quantity of undesired signal has obvious minimizing; Fig. 7 is that LED is not luminous, and the signal under adopting after wrapping gobo, can find out, through shading treatment, the noise signal of interference when-1100V, substantially all at below 100mV, as shown in Figure 6; Each the little lattice width setting oscillograph 15 is herein 20 μ s, be highly 100mV, and when actual measurement photomultiplier tube signal, setting each little lattice width is 20ns, highly constant, can see that undesired signal is relative or little, not be very large on measuring by the measurement impact driving the photomultiplier produced to output signal, namely there will not be too much spurious count;
C) input drive signal, measures the signal of photomultiplier;
The drive singal of (I) opening time-delaying device 8, arranges frequency, high pressure, the signal of observation oscilloscope 15;
The drive singal of manual unlocking chronotron 8, after this time delay plug-in unit N93B is just sustainable provides drive singal, and its frequency is 2000Hz, then adds the high pressure of-1100V to photomultiplier, is observed put plug-in unit 13 signal out by oscillograph before fast; When not taking optical attenuation measure, can see the signal of the superimposed pulses that a lot of amplitude is larger, its pulse amplitude values can be larger;
(II) changes the luminance brightness inciding photomultiplier by optical attenuation, the change of signal in observation oscilloscope;
When the thickness slowly increasing decay institute paper using changes the luminance brightness inciding photomultiplier, thus change photoelectronic generation probability, can see that output pulse amplitude value is in reduction; When luminance brightness is reduced to certain value, the change of photomultiplier amplitude output signal is little, and the example number that is associated with LED reduces very soon, now can think that single photoelectron example is relatively high;
(III) analyzes the impact of optical attenuation on signal;
The pulse signal that when not taking optical attenuation measure, photomultiplier exports is shown in (a) figure in Fig. 8, the amplitude of its every little lattice representative is 200mV, and (b) figure in Fig. 8 be depicted as single photoelectron example higher time, the amplitude of its every little lattice representative is 100mV, visible along with optical attenuation, the photon entering photomultiplier reduces, and the amplitude output signal of photomultiplier slowly reduces;
D) single photoelectron data are gathered
Under photomultiplier is all operated in the high pressure of-1100V, once need first high pressure to be reduced to 0 before image data on carrying out, carry out gather prepare after go up again, in order to avoid operating process not at that time high pressure human body is damaged; After oscillograph is observed the output signal of photomultiplier, the brightness of adjustment LED lamplight, after making it decay, the change of photomultiplier amplitude output signal is little, if can to observe in step (2) b), the c) phenomenon stated of step, then illustrating that each experimental apparatus all works in normal state, now doing adjusting slightly at the paper number for decaying, as change blocks the thickness of LED paper from 1 to 3, image data respectively; Only digital to analog converter FADC need be opened during image data, in computer, corresponding software arrange memory address;
Block before this experiment acquires LED respectively 9,8,7,6,5 paper time the photomultiplier signal that exports, each gather 100,000 data;
E) data analysis
By the data analysis process collected in the d) step, and draw the single photoelectron spectrum often organizing 100,000 data, so just can have conclusion more intuitively to the single photoelectron response of photomultiplier; This raw data is stored as bin form, under operating in ROOT environment, draws single photoelectron spectrum and matching, and draw the parameter such as peak-to valley ratio and resolution according to each spectrum of gained to data programmed process during analysis; The output signal of single photoelectron is approximately a Landau distribution, signal export and single photon spectrum as shown in Figure 10, the photomultiplier single photon spectrum recorded can by following exponential function matching background:
exp0(x)＝exp(p0+p1|x) (1)
And by following two Gaussian function fitting single photoelectron peak positions;
gaus1(x)＝p2/exp(-0.5*((x-p3)/p4)^2) (2)
gaus2(x)＝p5*exp(-0.5*((x-p6)/p7)^2) (3)
Last matched curve:
simul ation(x)＝expo(x)+gaus1(x)+gaus2(x) (4)
Wherein p0 to p7 corresponds to the fitting parameter in figure, exponential signal expo (x) characterizes noise spectrum, gaussian signal gaus1 (x) characterizes single photon spectrum, gaussian signal gaus2 (x) characterizes multi-photon spectrum, during sampling single photon pulses, the area integral of pulse equals the number of channels corresponding to single photoelectron spectrum peak.
(3) convolution of signal
A) get a little to single photon impulse response function;
(I) carries out described point and record by software digitizer to the single photon impulse Response Function image obtained in step (2);
Stochastic choice single photon signal, integration corresponds to the number of channels corresponding to single photon spectrum peak, utilizes software Plotdigitizer to carry out Sample point collection to single photon signal, and obtained point as shown in Figure 9, is recorded by sampling;
The described point that (II) obtains in software Matlab by outside error, the point that obviously do not belong to single photon signal rejects, fitting function;
The point obtained in software Matlab by outside error, the point that obviously do not belong to single photon signal rejects; Finally the data separate Matlab obtained is done fitting function, obtain impulse response function h (t) of single photon Landau distribution;
B) convolution comparing;
Respectively by the neutron of simulating in step (1) and the gamma convolution function conv (x1 by software Matlab, x2), single photon impulse response function h (t) and its signal g (t) that photon produces in time in liquid scintillation bulk detector are made convolution: it should be noted that, because the single photon signal gathered is lattice with 20ns, so also need the time interval of single photon impulse response to be consistent when convolution.
To simulate neutron and simulation gamma respectively, true neutron and true gamma are put together after normalization and compare, as shown in figure 12, wherein
represent simulation gamma ray,
represent true gamma ray,---represent simulation neutron ray,---represent true neutron ray; Change detector shape, size etc., obtain the ability that different detectors screens neutron and gamma, select a size liquid scintillator detector, thus optimize the examination neutron of liquid scintillation bulk detector and the detector of gamma.In the following Figure 12 of Comparative result pulse diagram a), b) figure: compare with real pulsion phase, the goodness of fit is relatively good; The size Selection optimum changing model fluid scintillator detector optimizes its examination neutron and gamma ability.In scintillator, the pulse fast composition share that gamma ray produces is little, slow composition share is many, neutron is then contrary, and therefore as shown in d figure in Figure 12, the rising edge of neutron and gamma ray almost overlaps, when first the negative edge of simulation neutron and simulation gamma is that neutron declines comparatively fast, then be that gamma declines comparatively fast, namely two lines have intersection point, and simulation neutron, simulation gamma ray are optimum time clear and legible.
List of references:
[1]I.Fedorko,S.Tokar.Simulation of Photomultiplier Response[J].ATL-TILECAL,1999,012:2-3。
[2] Soren JETTER, Dan DWYER. photomultiplier waveform modeling at the Daya Bayexperiment [J] .Chiness Physics C, 2012,36 (8): 734-735.
[3]S.Riggi,P.La Rocca.GEANT4simulation of plastic scintillator stripswith embedded optical fibers for a prototype of tomographic system[J].NuclearInstruments and Methods in Physics Research A,2010,624:585。
[4]EJ331-335GADOLINIUM LOADED LIQUID SCINTILLATORS.
http://www.ggg-tech.co.jp/naker/eljen/ej331.html。
[5]GANT4USE’S GUIDE。
[6] radiation detection and measurement [M]. Sichuan University, 102.
Claims (7)
1. optimize the method that liquid scintillation bulk detector screens neutron and gamma ability, it is characterized in that by Monte-carlo Simulation particle photon production process in time in liquid scintillator; Then the output signal of single photon at photomultiplier is obtained by single photon experiment; The photon sequence produced in random selecting model fluid scintillator detector again and the single photon signal convolution exported at photomultiplier, to realize the actualization of model fluid scintillator detector particle signal; And by regulating and optimize the parameter of liquid scintillation bulk detector, design with this and improve the ability that liquid scintillation bulk detector screens neutron and gamma; Comprise following operation steps:
(1) Monte Carlo light signal is simulated
A) software Geant 4 model fluid scintillator detector (7) is used;
B) generation of software Geant4 simulated photons is used;
(2) single photon experiment
A) connect and debug instrument;
B) measure and observe the undesired signal that photomultiplier (12) thermonoise and light leak produce;
Not luminous at light emitting diode (11), and collection signal under wrapping gobo situation, then undesired signal is obtained after the selection of shading treatment and threshold value;
C) input drive signal, measures the signal of photomultiplier (12);
D) single photoelectron data are gathered;
Adjustment light emitting diode (11) luminance brightness, makes it decay, and when the change of photomultiplier (12) amplitude output signal is little, gathers single photoelectron data;
E) data analysis;
Process matching is carried out to the single photoelectron data gathered and obtains single photon impulse response function;
(3) convolution of signal
A) get a little to single photon impulse response function;
B) use software Matlab to described step a) in taken point carry out interpolation and obtain single photon response function, choose and the point at the light signal same time interval that photon produces in time in liquid scintillation bulk detector described in step (1);
C) get light signal convolution in software Matlab that in single photon impulse response function and model fluid scintillator detector, photon produces in time at random, the signal that the signal after convolution and real particles obtain is compared.
2. method according to claim 1, it is characterized in that model fluid scintillator detector described in step (1) a), its concrete practice first arranges designed liquid scintillation bulk detector (7) size, form parameter, uses software Geant 4 to simulate and designed liquid scintillation bulk detector (7) described size, detector that shape is identical.
3. method according to claim 1, it is characterized in that the generation of simulated photons described in step (1) is b), its concrete practice arranges following parameter:
(I) arranges photon number, resolution, energy value, speed time parameter; According to liquid scintillation volume property used, required photon number, the resolution of scintillator, energy value, speed time parameter in simulation process are set;
(II) arranges border between photomultiplier and photoconduction and parameter thereof; Border experimentally between room condition setting photomultiplier (12) and photoconduction (2) is dielectric metal, and arranges its reflectivity, efficiency parameters; Obtain neutron, Monte Carlo light signal that gamma is simulated in liquid scintillator, be the point of series of equivalent time interval.
4. method according to claim 1, it is characterized in that debugging each instrument used described in step (2) is a), its concrete practice is:
(I) debugs the drive singal of chronotron used, sets the frequency of described drive singal, width;
(II) makes camera bellows, optical attenuator, shielding external interference;
(III) sets high pressure used, is observed the signal output waveform of photomultiplier by oscillograph.
5. method according to claim 1, it is characterized in that the light signal measuring photomultiplier described in step (2) is c), its concrete practice is:
The drive singal of (I) opening time-delaying device, arranges frequency, high pressure used, is observed the signal output waveform of photomultiplier by oscillograph;
(II) changes the luminance brightness inciding photomultiplier by optical attenuation, the change of photomultiplier signal output waveform in observation oscilloscope;
(III) analyzes the impact of optical attenuation on signal.
6. method according to claim 1, it is characterized in that getting a little to single photon impulse response function described in step (3) is a), its concrete practice is:
(I) carries out described point and record by software digitizer to the single photon impulse response function image obtained in step (2);
(II) by the described point obtained in software Matlab by outside error, the point that obviously do not belong to single photon signal rejects.
7. method according to claim 1, is characterized in that in liquid scintillation bulk detector described in step (3) is b), photon produces the point at signal same time interval in time, is completed by step below:
(I) utilizes software Matlab method of interpolation fitting function;
(II) utilizes software Matlab to choose and the point at the signal same time interval that photon produces in time in liquid scintillation bulk detector.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310214857.9A CN103336293B (en) | 2013-05-31 | 2013-05-31 | A kind of method optimizing liquid scintillation bulk detector examination neutron and gamma ability |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310214857.9A CN103336293B (en) | 2013-05-31 | 2013-05-31 | A kind of method optimizing liquid scintillation bulk detector examination neutron and gamma ability |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN103336293A CN103336293A (en) | 2013-10-02 |
| CN103336293B true CN103336293B (en) | 2015-09-16 |
Family
ID=49244496
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201310214857.9A Expired - Fee Related CN103336293B (en) | 2013-05-31 | 2013-05-31 | A kind of method optimizing liquid scintillation bulk detector examination neutron and gamma ability |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN103336293B (en) |
Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104898158B (en) * | 2014-03-04 | 2019-02-15 | 环境保护部核与辐射安全中心 | Neutron DE measurement method and measuring device |
| CN104898157B (en) * | 2014-03-04 | 2019-02-22 | 环境保护部核与辐射安全中心 | Neutron DE measuring device and measuring method |
| CN104678425B (en) * | 2015-02-02 | 2017-03-22 | 中国原子能科学研究院 | Fast-neutron multiple measuring-analyzing method based on liquid scintillation detector |
| CN107548426A (en) * | 2015-06-03 | 2018-01-05 | 哈利伯顿能源服务公司 | Pressure balance liquid scintillator for underground γ detections |
| CN105093261B (en) * | 2015-08-20 | 2018-08-24 | 中国原子能科学研究院 | A kind of neutron, the γ discrimination systems of digitlization neutron spectrometer |
| CN107450090A (en) | 2016-06-01 | 2017-12-08 | 南京中硼联康医疗科技有限公司 | Radiation dose measurement method |
| CN106597521A (en) * | 2016-12-28 | 2017-04-26 | 中国工程物理研究院激光聚变研究中心 | Fast neutron detector resisting interference of strong gamma rays and application method thereof |
| CN109143317B (en) * | 2017-06-16 | 2023-05-16 | 中国辐射防护研究院 | Neutron detection method and equipment for reducing gamma ray interference by using CsI scintillator |
| 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 |
| CN110515115B (en) * | 2018-05-22 | 2022-11-25 | 中国辐射防护研究院 | Evaluation method for solving peak area of gamma spectrum |
| CN109239765B (en) * | 2018-08-28 | 2022-10-11 | 南昌大学 | Nuclear-like pulse generation device and method |
| CN109669206A (en) * | 2019-03-03 | 2019-04-23 | 南昌华亮光电有限责任公司 | Circulating type liquid scintillator intelligence energy disperse spectroscopy system and its signal processing method |
| CN112505742B (en) * | 2020-11-07 | 2022-08-26 | 成都理工大学工程技术学院 | Digital n-gamma discrimination method based on falling edge integration |
| CN114152639A (en) * | 2021-11-19 | 2022-03-08 | 四川大学 | Gamma neutron activation analysis method capable of removing neutron interference |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101556331A (en) * | 2009-05-05 | 2009-10-14 | 西北核技术研究所 | Optical fiber coupling organic scintillating fiber pulse neutron probe |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011060166A2 (en) * | 2009-11-12 | 2011-05-19 | Saint-Gobain Cermics & Plastics, Inc. | Scintillation pixel design and method of operation |
| US20130112885A1 (en) * | 2010-07-21 | 2013-05-09 | Hiroshima University | Phoswich thermal neutron detector |
-
2013
- 2013-05-31 CN CN201310214857.9A patent/CN103336293B/en not_active Expired - Fee Related
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101556331A (en) * | 2009-05-05 | 2009-10-14 | 西北核技术研究所 | Optical fiber coupling organic scintillating fiber pulse neutron probe |
Non-Patent Citations (4)
| Title |
|---|
| Digital discrimination of neutrons and γ-rays in liquid scintillators using pulse gradient analysis;B. D’Mellow et al.;《Nuclear Instruments and Methods in Physics Research A》;20070721;第578卷(第1期);第191-197页 * |
| Measurements of (n,γ) neutron capture cross-sections with liquid scintillator detectors;J.N. Wilson et al.;《Nuclear Instruments and Methods in Physics Research A》;20031001;第511卷(第3期);第388-399页 * |
| 基于 Geant4 的射线探测仿真并行化研究;王力 等;《核电子学与探测技术》;20111130;第31卷(第11期);第1237-1240页 * |
| 提高塑料闪烁体n/γ 甄别能力的一种新途径;冯璟华 等;《核电子学与探测技术》;20110930;第31卷(第9期);第939-942页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN103336293A (en) | 2013-10-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103336293B (en) | A kind of method optimizing liquid scintillation bulk detector examination neutron and gamma ability | |
| Flaska et al. | Identification of shielded neutron sources with the liquid scintillator BC-501A using a digital pulse shape discrimination method | |
| CN106990429B (en) | Gamma and neutron dual-ray energy spectrum measuring device and measuring method | |
| CN103698801B (en) | The multilayer scintillation detector of high energy proton and neutron spectrum measurement and measuring method | |
| CN106547017A (en) | A kind of compound scintillator gamma ray spectrometer | |
| Joyce et al. | The design, build and test of a digital analyzer for mixed radiation fields | |
| CN105093261A (en) | Neutron and gamma ray discrimination system of digital neutron spectrometer | |
| CN106707059A (en) | Large-area micro channel plate type photomultiplier test apparatus and test method | |
| US11754729B2 (en) | Nuclear detection simulation device based on nanosecond light source and nuclear signal inversion technology | |
| Kindin et al. | Cherenkov water detector NEVOD: a new stage of development | |
| CN106226339A (en) | Neutron produces equipment, neutron imaging equipment and formation method | |
| Ely et al. | Final technical report for the neutron detection without helium-3 project | |
| CN103054594B (en) | A kind of Automatic trigger exposure circuit of flat panel detector | |
| CN106443758A (en) | Anticoincidence based positron annihilation detecting method and system | |
| Liao et al. | n/γ Pulse shape discrimination comparison of EJ301 and EJ339A liquid scintillation detectors | |
| Zhang et al. | Comparison on PMT waveform reconstructions with JUNO prototype | |
| CN102183778B (en) | A kind of scintillation detector | |
| CN103257357A (en) | Simplified digital corresponding Doppler broadening spectrum machine | |
| CN106154303B (en) | Signal processing apparatus and time detection device | |
| CN205176285U (en) | Anticoincidence output system of examineing | |
| CN105492929B (en) | Radiation detecting apparatus and radiation dose measurement processing method | |
| CN203720091U (en) | Biological weak light signal detection circuit | |
| Skulski et al. | FemtoDAQ: A low-cost digitizer for SiPM-based detector studies and its application to the HAWC detector upgrade | |
| Ruben et al. | A new four channel pulse shape discriminator | |
| Xing et al. | Simulation study of the neutron–gamma discrimination capability of a liquid scintillator neutron detector |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20150916 Termination date: 20170531 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |