CN2890900Y - Apparatus employing fast neutron and continuous energy spectrum X ray to recognize material - Google Patents

Abstract

A device for identifying materials by fast neutrons and continuant energy spectrum X-rays relates to a large object radiation imaging detecting technical field, wherein a fast neutron source and a continuant energy spectrum pulse X-ray source are equipped on one side of a detecting path with a neutron detector and an X-ray detector equipped on one side of the detecting path. The fast neutron source sends out straight neutron beams which pass through a neutron bean collimator, and the continuant energy spectrum pulse X-ray source sends out straight continuant energy spectrum X-rays through an X-ray bean collimator to penetrate the detected objects and then respectively adjusts to the neutron detector and the X-ray detector. The utility model adopts atom sequence related n-x curving equivalent with the detected objects to identify materials, and utilizes the high-penetration capacity of the continuant energy spectrum X-ray to identify materials when the containers are full or the detected objects are thick with simple equipments, clear imaging and high precision rate of real-time detecting.

Description

A kind of device that carries out material identification with fast neutron and continuum X ray

Technical field

The utility model relates to large object radiant image detection technique fields such as container, and the device of material identification is carried out in the continuum X ray decay of particularly directly measuring x-ray sources generations such as fast neutron and accelerator.

Background technology

Along with the sternness day by day of anti-terrorism situation, the radiant image container examination system with explosive, drugs, the automatic recognition function of thing of violating a ban becomes urgent market demand.The material identification technology of large objects such as existing container comprises X ray high-energy double-energy imaging technique, neutron activation technique and container CT, all more and more is subject to people's attention.

X ray high-energy double-energy imaging technique utilizes the attenuation degree difference of Compton effect and pair effect, judges the equivalent atom ordinal number of checking matter, thereby distinguishes different material.But disturb owing to exist between the high and low energy of continuous spectrum X ray that accelerator sends,, can only be used for distinguishing organism, inorganics, potpourri even add that energy reforming also can only reduce part and disturb.Isotope source can provide monoenergetic gamma rays, but capacity volume variance is too little, penetration power is too low, is not suitable for the detection and the material identification equipment of large objects such as container.

The neutron activation technique that is used for inspection of containers has 3 dimensional imaging PFNA systems based on time-of-flight method, but involve great expense, detection speed is too slow.Thermal capture γ penetration power is too low.Existing C f-252 neutron source inspection of containers device can not be done online real-time measurement, can only treat that other means are checked out suspicious object after, could carry out neutron activation to suspected locations and detect.

Container CT technology equipment needed thereby is too huge, and because speed can't be used for real-time measurement more slowly.

Australia CSIRO Minerals develops the device (CSIRO contraband scanner) of a kind of direct measurement monoenergetic fast neutron and monoenergetic gamma rays.What this device utilized attenuation coefficient recently distinguishes different materials, is used for explosive, the drugs of air container, the quality testing of violating a ban is surveyed.Compare with X ray high-energy double-energy technology, monoenergetic fast neutron and monoenergetic gamma rays dual intensity technologic material resolution characteristic are stronger.Compare with neutron activation technique, monoenergetic fast neutron and monoenergetic gamma rays dual intensity commercial measurement be a ray, survey the detection efficiency of the Secondary radiation that the school rate measures far above neutron activation technique, penetration power is much larger than thermal neutron.Compare with container CT, equipment volume is little, cost is low, can do real-time measurement.But this defective of utilizing attenuation coefficient recently to distinguish the monochromatic energy dual intensity technology maximum of different materials is it can only use the monoenergetic gamma rays source of isotope source as it.And isotope source is too low as inspection of containers device penetration power, spatial resolution is too poor, poor image quality, radiation safety difficult management.This device can only provide the low container scanning image of differentiating, and compares with the high-quality scan image that the LINAC container check system provides, and is difficult to the user and accepts.Because the gamma-rays penetration power is too low, expiring under the very thick situation of container or checking matter, can not carry out material identification, so also limited its range of application greatly.

Summary of the invention

In order to overcome above-mentioned deficiency of the prior art, the purpose of this utility model provides a kind of device that carries out material identification with fast neutron and continuum X ray.The utility model adopts only relevant with the equivalent atom ordinal number Z of tested object n-x curve to carry out material identification, the high penetrating power that utilizes continuum X ray and fast neutron to have, expiring under the very thick situation of container or checking matter, also can carry out material identification, have that equipment is simple, imaging is clear, detect the high characteristics of accuracy rate.

In order to reach above-mentioned goal of the invention, the technical solution of the utility model realizes as follows:

A kind ofly carry out a kind of device of material identification with fast neutron and continuum X ray, it comprises sense channel and tested object that can be placed on it.Its design feature is that it also comprises fast neutron source, continuum pulsed X-ray source, neutron detector and X-ray detector.Described fast neutron source and continuum pulsed X-ray source place a side of sense channel, and neutron detector and X-ray detector place the opposite side of sense channel.Fast neutron source is sent and the fast neutron bundle by neutron beam collimation device collimation and send in continuum pulsed X-ray source and the continuum X-ray beam by the X-ray beam collimating device collimation penetrates behind the tested object respectively over against neutron detector and X-ray detector.

In said apparatus, pulse fast neutron source or isotope neutron source that described fast neutron source adopts neutron generator to produce, described generation continuum pulsed X-ray source is electron linear accelerator or X-ray machine.

In said apparatus, described neutron scanning support that is formed by fast neutron source and neutron detector and the X-ray scanning frame that is formed by continuum x-ray source and X-ray detector are placed side by side in sense channel, make tested object earlier by the X-ray scanning frame again by the neutron scanning support.

A kind ofly carry out the another kind of device of material identification with fast neutron and continuum X ray, it comprises sense channel and tested object that can be placed on it.Its design feature is that it also comprises accelerator, neutron detector and the X-ray detector that can produce continuum pulsed X-ray source and phot-neutron source.Described accelerator places a side of sense channel, and neutron detector and X-ray detector place the opposite side of sense channel.The front end in the continuum pulsed X-ray source of described accelerator is equipped with binary channels shunting collimating apparatus, one road X-ray beam forms the continuum pulsed x-ray beam by the X-ray beam collimating apparatus in the binary channels shunting collimating apparatus, and another road X-ray beam enters in the photoneutron enhancing chamber and beats on photoneutron conversion intensifier target by the shunting collimating apparatus in the binary channels shunting collimating apparatus and produces photoneutron.Photoneutron is through strengthening the photoneutron passage formation photoneutron bundle that the chamber links to each other with photoneutron, and photoneutron bundle and continuum X-ray beam penetrate behind the tested object respectively over against neutron detector and X-ray detector.

In said apparatus, described continuum X-ray beam and the photoneutron bundle that is sent by continuum pulsed X-ray source forms X-ray scanning frame and neutron scanning support with X-ray detector and neutron detector respectively, placed side by side in sense channel, make tested object pass through the neutron scanning support again by the X-ray scanning frame earlier.

In said apparatus, the material of described photoneutron conversion intensifier target is a beryllium, photoneutron conversion intensifier target be shaped as circular arc, cylindrical, conical or L shaped.

In said apparatus, be provided with the bismuth filter plate between photoneutron conversion intensifier target in the described photoneutron enhancing chamber and the photoneutron passage.

In said apparatus, described photoneutron strengthens the chamber and adopts lead and graphite composite material to make.

The utility model is owing to adopted above-mentioned technical scheme, utilize, with the equivalent atom coefficient Z of the checking matter relevant n-x curve irrelevant with checking matter thickness of the different formations with continuum X ray transmission decay intensity of fast neutron to carry out material identification, equipment is simple, detection efficiency is high.Tested object is earlier by the X-ray scanning frame, the back is by the neutron scanning support, eliminated of the influence of the gamma-rays of neutron activation generation to the X-ray scanning image, and the launch time of gating pulse neutron beam launch time certain delay is arranged with respect to pulsed x-ray beam, can reduce the phase mutual interference like this, imaging is more clear.Neutron beam and X-ray beam all are narrow beams, have reduced diffuse transmission influence, are easy to protection, and can improve spatial resolution.The utility model also can carry out material identification expiring under the very thick situation of container or checking matter, can be used for explosive, the drugs of large objects such as container, container car, train, the article detections such as thing, special nuclear material of violating a ban.

Below in conjunction with the drawings and specific embodiments the utility model is described further.

Description of drawings

Fig. 1 is the structural representation of a kind of device for carrying out said of the utility model;

Fig. 2 is the structural representation of the another kind of device for carrying out said of the utility model;

Fig. 3 is the structural representation of neutron beam of the present utility model and X-ray beam emitter.

Embodiment

Embodiment one

Referring to Fig. 1, the utility model device comprises sense channel 32, tested object 34, fast neutron source 12, continuum pulsed X-ray source 22 that can be placed on it, neutron detector 18 and the X-ray detector 28 that respectively neutron and X ray is had high detection efficiency.Pulse fast neutron source or isotope fast neutron source that fast neutron source 12 adopts neutron generator to produce, continuum pulsed X-ray source 22 is electron linear accelerator or X-ray machine.Fast neutron source 12 and continuum pulsed X-ray source 22 place a side of sense channel 32, and neutron detector 18 and X-ray detector 28 place the opposite side of sense channel 32.Making fast neutron source 12 send and pass the fast neutron bundle 16 of neutron beam collimation device and continuum X-ray beam 26 that the X-ray beam collimating apparatus was sent and passed in continuum pulsed X-ray source 22 penetrates behind the tested object 34 respectively over against neutron detector 18 and X-ray detector 28.Formed neutron scanning support and X-ray scanning frame are placed at interval in sense channel 32 side by side, and make along tested object 34 traffic direction X-ray scanning framves preceding, neutron scanning support after.

Method step when the utility model device uses is:

1. neutron scanning support that fast neutron source 12 and neutron detector 18 formed and the X-ray scanning frame that formed by continuum x-ray source 22 and X-ray detector 28 are placed side by side in the direction of scanning, make tested object 34 pass through the neutron scanning support again by the X-ray scanning framves earlier.Fast neutron bundle 16 and continuum X-ray beam 26 that the continuum x-ray source 22 that pulse fast neutron source 12 that produces with neutron generator or isotope fast neutron source 12 and accelerator or X-ray machine produce launch respectively penetrate tested object 34, directly measure also difference scanning imagery of fast neutron bundle 16 and continuum X-ray beam 26 respectively with neutron detector 18 and X-ray detector 28.If what use is the pulse fast neutron source 12 that neutron generator produces, then requiring has launch time of the continuum x-ray source 22 that pulse fast neutron source 12 produces with respect to accelerator certain delay.

2. utilize fast neutron bundle 16 to carry out material identification with the different formed curve of continuum X-ray beam 26 decay.The method of material identification is: measuring the neutron intensity that penetrates tested object 34 with neutron detector 18 is T _n, measuring the X ray intensity that penetrates tested object with X-ray detector 28 is T _xWith c ₁=-lnT _x* scale is a horizontal ordinate, with c ₂=-lnT _n* scale is an ordinate, paired point (c ₁, c ₂) a formation n-x curve relevant with equivalent atom coefficient Z.The gray-scale value of a pixel of neutron scan image is searched the n-x curve corresponding to the average of the gray scale of one or several pixel of X-ray scanning image, represents different materials with different colours on scan image.

The above-mentioned T that uses _nAnd T _xThe method that obtains the equivalent atom ordinal number Z of checking matter 34 is:

Index law is observed in the decay of narrow beam monochromatic neutron beam in checking matter:

$I_n=I_n{e}^{-{\mathrm{\μ}}_{n}x}---\left(1\right)$

In the formula:

I _n: the transmission neutron beam intensity,

I _N0: the incident neutron beam intensity,

μ _n: checking matter is to the attenuation coefficient summation of incident neutron,

X: checking matter thickness,

The decay formula of narrow beam continuum neutron beam in checking matter:

$I_n={\∫}_0^{\mathrm{Enb}}{I}_{n0}\left(E\right)e^{-{\mathrm{\μ}}_n(E,Z)x}\mathrm{dE}---\left(2\right)$

In the formula:

I _N0(E): energy is the incident neutron beam intensity of E,

μ _n(E, Z): the equivalent atom coefficient be the checking matter of Z to energy be E neutron attenuation coefficient and,

E _Nb: the border energy of neutron beam,

The decay formula of narrow beam continuum X ray in tested object:

$I_x=\underset{0}{\overset{\mathrm{Exb}}{\∫}}{I}_{x0}\left(E\right)e^{-{\mathrm{\μ}}_x(E,Z)x}\mathrm{dE}---\left(3\right)$

In the formula:

Ix: the Transmission X ray beam intensity,

I _X0(E): energy is the incident X-rays beam intensity of E,

μ _x(E, Z): the equivalent atom coefficient be the checking matter of Z to energy be E X-ray beam attenuation coefficient and,

E _Xb: the border energy of X-ray beam,

Be all under the situation of continuum at neutron beam 16 and X-ray beam 26, material discerned with following nonlinear integral equation group:

$\left\{\begin{array}{c}{T}_n(E,x,Z)=\frac{{\∫}_0^{E_{\mathrm{nb}}}{I}_{n0}\left(E\right)e^{-{\mathrm{\μ}}_n(E,Z)x}\mathrm{dE}}{{\∫}_0^{E_{\mathrm{nb}}}{I}_{n0}\left(E\right)\mathrm{dE}}\\ T_x(E,x,Z)=\frac{{\∫}_0^{E_{\mathrm{xb}}}{I}_{x0}\left(E\right)e^{-{\mathrm{\μ}}_x(E,Z)x}\mathrm{dE}}{{\∫}_0^{E_{\mathrm{xb}}}{I}_{x0}\left(E\right)\mathrm{dE}}\end{array}\right.---\left(4\right)$

In the formula:

T _n(Z): expression equivalent atom ordinal number is that Z, thickness are that the material of x is the transparency of the neutron beam of Enb to the border energy for E, x,

T _x(Z): expression equivalent atom ordinal number is that Z, thickness are that the material of x is the transparency of the X-ray beam of Exb to the border energy for E, x,

At neutron beam 16 is monoenergetic E _n, and X-ray beam 26 is under the situation of continuum, with following nonlinear integral equation group material is discerned:

$\left\{\begin{array}{c}{T}_n(E_n,x,Z)=I_{n0}{e}^{-{\mathrm{\μ}}_n(E_n,Z)x}\\ T_x(E,x,Z)=\frac{{\∫}_0^{E_{\mathrm{xb}}}{I}_{x0}\left(E\right)e^{-{\mathrm{\μ}}_x(E,Z)x}\mathrm{dE}}{{\∫}_0^{E_{\mathrm{xb}}}{I}_{x0}\left(E\right)\mathrm{dE}}\end{array}\right.---\left(5\right)$

By finding the solution nonlinear integral equation group (4) or (5), cancellation checking matter 34 thickness x, the equivalent atom ordinal number Z of release checking matter 34.

The utility model is when carrying out material tests, can be by mobile neutron scanning support and X-ray scanning frame scan detection to container or other large object that is placed on the sense channel 32 simultaneously, also fixedly neutron scanning support and X-ray scanning frame detect and tested container or other large object are moved finish scanning on sense channel 32.

Embodiment two

Referring to Fig. 2 and Fig. 3, the utility model comprises sense channel 32, tested object 34 that can be placed on it, the accelerator 42 that can produce continuum pulsed X-ray source and phot-neutron source, neutron detector 18 and X-ray detector 28.Accelerator 42 places a side of sense channel 32, and neutron detector 18 and X-ray detector 28 place the opposite side of sense channel 32.The front end in the continuum pulsed X-ray source 22 of accelerator 42 is equipped with binary channels shunting collimating apparatus 52, the X-ray beam collimating apparatus that one road X-ray beam is shunted in the collimating apparatus 52 by binary channels forms continuum pulsed x-ray beam 26, and another road X-ray beam 58 enters in the photoneutron enhancing chamber 50 that employing is plumbous and the graphite composite material is made and by L shaped photoneutron conversion intensifier target 56 by the shunting collimating apparatus in the binary channels shunting collimating apparatus 52 and produces photoneutrons.Photoneutron forms photoneutron bundle 16 through bismuth filter plate 60 and the photoneutron passage 51 that photoneutron strengthens in the chamber 50, and photoneutron bundle 16 and continuum X-ray beam 26 penetrate tested object 34 backs over against neutron detector 18 and X-ray detector 28.The continuum X-ray beam 26 and the photoneutron bundle 16 that are sent by continuum pulsed X-ray source 22 form X-ray scanning frame and neutron scanning support with X-ray detector 28 and neutron detector 18 respectively, placed side by side in sense channel 32, preceding, the neutron scanning support is in back and separated by a distance along tested object traffic direction X-ray scanning frame.

Method step when the utility model device uses is identical with embodiment one, does not repeat them here.

Claims (8)

1, a kind of device that carries out material identification with fast neutron and continuum X ray, it comprises sense channel (32) and tested object (34) that can be placed on it, it is characterized in that, it also comprises fast neutron source (12), continuum pulsed X-ray source (22), neutron detector (18) and X-ray detector (28), described fast neutron source (12) and continuum pulsed X-ray source (22) place a side of sense channel (32), neutron detector (18) and X-ray detector (28) place the opposite side of sense channel (32), fast neutron source (12) are sent and the fast neutron bundle (16) by neutron beam collimation device collimation and send in continuum pulsed X-ray source (22) and the continuum X-ray beam (26) by the X-ray beam collimating device collimation penetrates behind the tested object (34) respectively over against neutron detector (18) and X-ray detector (28).

2, the device that carries out material identification with fast neutron and continuum X ray according to claim 1, it is characterized in that, pulse fast neutron source or isotope neutron source that described fast neutron source (12) adopts neutron generator to produce, described generation continuum pulsed X-ray source (22) is electron linear accelerator or X-ray machine.

3, the device that carries out material identification with fast neutron and continuum X ray according to claim 1 and 2, it is characterized in that, described neutron scanning support that is formed by fast neutron source (12) and neutron detector (18) and the X-ray scanning frame that is formed by continuum x-ray source (22) and X-ray detector (28) are placed side by side in sense channel (32), make tested object (34) earlier by the X-ray scanning frame again by the neutron scanning support.

4, a kind of device that carries out material identification with fast neutron and continuum X ray, it comprises sense channel (32) and tested object (34) that can be placed on it, it is characterized in that, it also comprises the accelerator (42) that can produce continuum pulsed X-ray source and phot-neutron source, neutron detector (18) and X-ray detector (28), described accelerator (42) places a side of sense channel (32), neutron detector (18) and X-ray detector (28) place the opposite side of sense channel (32), the front end in the continuum pulsed X-ray source (22) of described accelerator (42) is equipped with binary channels shunting collimating apparatus (52), the X-ray beam collimating device collimation that one road X-ray beam is shunted in the collimating apparatus (52) by binary channels forms continuum pulsed x-ray beam (26), another road X-ray beam (58) enters in the photoneutron enhancing chamber (50) by the shunting collimating apparatus in the binary channels shunting collimating apparatus (52) and beats at photoneutron conversion intensifier target (56) and upward produces photoneutron, photoneutron is through strengthening photoneutron passage (51) the formation photoneutron bundle (16) that chamber (50) links to each other with photoneutron, and photoneutron bundle (16) and continuum X-ray beam (26) penetrate behind the tested object (34) respectively over against neutron detector (18) and X-ray detector (28).

5, the device that carries out material identification with fast neutron and continuum X ray according to claim 4, it is characterized in that, described continuum X-ray beam (26) and the photoneutron bundle (16) that is sent by continuum pulsed X-ray source (22) forms X-ray scanning frame and neutron scanning support with X-ray detector (28) and neutron detector (18) respectively, placed side by side in sense channel (32), along making tested object (34) pass through the neutron scanning support again by the X-ray scanning frame earlier.

6, according to claim 4 or the 5 described devices that carry out material identification with fast neutron and continuum X ray, it is characterized in that, the material of described photoneutron conversion intensifier target (56) is a beryllium, photoneutron conversion intensifier target (56) be shaped as circular arc, cylindrical, conical or L shaped.

7, the device that carries out material identification with fast neutron and continuum X ray according to claim 6, it is characterized in that, be provided with bismuth filter plate (60) between photoneutron conversion intensifier target (56) in the described photoneutron enhancing chamber (50) and the photoneutron passage (51).

8, according to claim 7ly carry out the device of material identification with fast neutron and continuum X ray, it is characterized in that, described photoneutron strengthens chamber (50) and adopts plumbous and the graphite composite material is made.