CN102109607B - Fast neutron detection method, substance identification methods and neutron detector - Google Patents
Fast neutron detection method, substance identification methods and neutron detector Download PDFInfo
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- CN102109607B CN102109607B CN2009102443573A CN200910244357A CN102109607B CN 102109607 B CN102109607 B CN 102109607B CN 2009102443573 A CN2009102443573 A CN 2009102443573A CN 200910244357 A CN200910244357 A CN 200910244357A CN 102109607 B CN102109607 B CN 102109607B
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Abstract
The invention discloses a fast neutron detection method, which is used for detecting fast neutrons with X-rays, and comprises the following steps: passing the fast neutrons through a neutron slowing body to absorb the X-rays and slow the fast neutrons into thermal neutrons; and detecting the thermal neutrons by using a thermal neutron detector to obtain the information on the fast neutrons. The invention also discloses a method for identifying substances by using photoneutrons, a method for identifying substances by using X-rays and the photoneutrons, and a neutron detector. The neutron detector comprises the neutron slowing body which is suitable for absorbing the X-rays therein and slowing the fast neutrons into the thermal neutrons; and the thermal neutron detector which is suitable for detecting the thermal neutrons to obtain the information on the fast neutrons. In the invention, the interference of the X-rays with the fast neutron measurement can be eliminated by arranging the neutron slowing body, so the accuracy of the neutron measurement is improved. And as the attenuation information of the X-rays and the attenuation information of the neutrons, which are different, are obtained at the same time, the capability of identifying detected objects is improved.
Description
Technical field
The present invention relates generally to and utilizes X ray and neutron to carry out the field of safety detection, relate more specifically to X ray the fast-neutron detection method, utilize the method for photoneutron recognition material, utilize method and the neutron detector of X ray and photoneutron recognition material simultaneously.
Background technology
Along with development economic and society, the range of application of safety detection technology is more and more wider, such as subway station, airport, bank, market etc., almost is seen everywhere.Safety detection technology has a variety of, it is a kind of technology that has obtained part Study that the photoneutron that wherein utilizes accelerator to produce carries out safety detection technology, having had the people utilizing photoneutron to carry out having done deep work aspect the ultimate analysis---the X ray bombardment that this method utilizes high-energy electron accelerator to produce comprises heavy water, berylliums etc. produce photoneutron at interior target with low photoneutron reaction threshold value, the photoneutron that produces reacts with some nucleic in the detected object, can emit and have distinctive gamma-rays, consist of by analyzing gamma-ray power spectrum, just can consist of the element of object to be detected and judge, thereby reach the purpose that material is identified.This method have can the recognition element kind special advantage, but its effect aspect image quality is relatively poor, has certain deficiency aspect the fusion mutually with radioscopic image.
Therefore another scheme has appearred, utilize the transmission information with differential declines characteristic of X ray and photoneutron to carry out imaging, simultaneously can access x-ray imaging and neutron transmission imaging two width of cloth images, by to X ray dampening information and neutron attenuation Information fusion, can improve the recognition capability to object to be detected.But this scheme also is in the principle stage, enable to realize, must solve a problem: how under the high power pulse of X ray, to realize the measurement to photoneutron? because photoneutron follows X ray to produce, although optical neutron converting target plays certain X ray shielding action, it is very many that but the X ray that enters neutron detector remains, and generally can think to surpass 4 magnitudes.Although neutron detector can be selected neutron-sensitive detector, but because the quantity of X ray is many excessively, no matter how insensitive this detector to X ray, generalized case is still X ray and has formed huge signal in neutron detector, significantly surpassed the signal that neutron detector forms therein, this reality so that obtaining of neutron transmission information can't finish.The present invention will address this problem exactly.
Summary of the invention
One of purpose of the present invention provides a kind of fast-neutron detection method, and the interference that the method is measured fast neutron by getting rid of X ray can be surveyed the fast neutron with X ray, thereby can improve the accuracy about the information of fast neutron.
Two of purpose of the present invention provides the method for utilizing the photoneutron recognition material, and the method can be got rid of the interference of the X ray of following photoneutron, therefore can improve the ability of recognition material.
Three of purpose of the present invention provides the method for utilizing simultaneously X ray and photoneutron recognition material, with the ability of further raising recognition material.
Four of purpose of the present invention provides the neutron detector that can detect with the fast neutron of X ray, and this neutron detector can be got rid of the interference that X ray is measured fast neutron, thereby improves the accuracy about the information of fast neutron.
The first purpose of the present invention is achieved by following scheme: a kind of fast-neutron detection method, be used for to survey the fast neutron with X ray, the method comprising the steps of: make described fast neutron by the moderation of neutrons body take absorption of x-rays and with Moderation of the fast neutrons as thermal neutron; With survey thermal neutron with thermal neutron detector to obtain the information about fast neutron.X ray will be absorbed by this slow body through for several times collision in the moderation of neutrons body afterwards, fast neutron can be thermal neutron by this slow body and by slowing down then, because X ray does not exist, survey like this thermal neutron and just can not be subject to the interference of X ray, thereby can improve the accuracy about the information of fast neutron.
As a preferred embodiment of fast-neutron detection method of the present invention, fast neutron was present in scattering thermal neutron in the environment through the thermal neutron shield with shielding first before entering the moderation of neutrons body.
The second purpose of the present invention is achieved by following scheme: a kind of method of utilizing the photoneutron recognition material comprises step: bombard optical neutron converting target to produce photoneutron with X ray; Guide described photoneutron transmission object to be detected; With the photoneutron that passes described object to be detected with the neutron detector detection; And comprise: the photoneutron that described object to be detected is passed in first guiding enter the moderation of neutrons body take absorption follow the X ray of described photoneutron and with described photoneutron slowing down as thermal neutron; Survey described thermal neutron to obtain the neutron transmission dampening information of the described material of identification by the thermal neutron detector in the described neutron detector again.
The 3rd purpose of the present invention is achieved by following scheme: a kind of method of utilizing simultaneously X ray and photoneutron recognition material comprises step: provide X ray; Guide the direct transmission object to be detected of first's X ray, and pass the X ray of described object to be detected to obtain the Transmission Attenuation information of described X ray with the X-ray detector detection; Guiding second portion X ray bombardment optical neutron converting target to be producing the photoneutron that is used for the transmission object to be detected, and surveys photoneutron by described object to be detected with the Transmission Attenuation information of acquisition photoneutron with neutron detector; In conjunction with the Transmission Attenuation information of the Transmission Attenuation information of described photoneutron and described X ray to identify the material of described object to be detected; The method also comprise first guiding pass the photoneutron of described object to be detected enter the moderation of neutrons body take absorption follow the X ray of described photoneutron and with described photoneutron slowing down as thermal neutron; Survey described thermal neutron to obtain the Transmission Attenuation information of described photoneutron by the thermal neutron detector in the described neutron detector again.Follow the X ray of photoneutron owing to crossed the moderation of neutrons bulk absorption, thereby got rid of the interference of X ray to neutron measurement, therefore can improve the accuracy of neutron transmission dampening information.In addition, utilize simultaneously the different X ray of attenuation characteristic and photoneutron to come inspected object, to obtain simultaneously two kinds of different Transmission Attenuation information, improved thus the recognition capability to inspected object.
The 4th purpose of the present invention is achieved by following scheme: a kind of neutron detector comprises: the moderation of neutrons body, and it is suitable for absorbing the X ray by wherein, and is thermal neutron with described Moderation of the fast neutrons; And thermal neutron detector, it is suitable for surveying described thermal neutron to obtain the information about neutron.This neutron detector by can absorption of x-rays allow fast neutron by and be the moderation of neutrons body of thermal neutron with this Moderation of the fast neutrons, can get rid of the interference of X ray, thereby improve the accuracy of measuring neutron information.
As a preferred embodiment of neutron detector of the present invention, neutron detector also comprises the thermal neutron shield, and it is suitable for shielding the scattering thermal neutron that is present in the environment.
Reach with reference to the accompanying drawings by reading following detailed description, other purposes of the present invention and advantage will become clearly.
Description of drawings
Fig. 1 is for producing the synoptic diagram of photoneutron;
Fig. 2 is the measurement sequential of photoneutron;
Fig. 3 is according to the synoptic diagram that utilizes simultaneously the method for X ray and photoneutron recognition material of the present invention;
Fig. 4 is the synoptic diagram according to an embodiment of neutron detector of the present invention.
Embodiment
As shown in Figure 1, one of known fast neutron producing method is exactly that the beam bombardment electric target 11 that is at first provided by electron accelerator produces X ray, bombards optical neutron converting target 12 to produce photoneutron with X ray again.The photoneutron target of generally using all is the nucleic with low light neutron threshold value, for example
9Be and
2H, therefore, beryllium target and heavy water target act on the neutron conversion body usually, and wherein, the reaction type of beryllium target can represent with following formula: γ+
9Be →
8Be+n, threshold value: 1.67MeV (1) wherein, γ represents photon, n represents neutron, the energy of neutron is determined by the difference of the energy of photon and the threshold of reaction.The reaction type of heavy water target then can represent with following formula: γ+
2H →
1H+n, threshold value: 2.223MeV (2) by above-mentioned reaction equation (1) and (2) as can be known, photoneutron follows X ray to produce, and it is generally acknowledged that the generation of photoneutron is identical with the generation of X ray constantly constantly.
Because the energy of this photoneutron to (specifically the energy by accelerator determines) between several MeV, therefore belongs to fast neutron at hundreds of keV.Although optical neutron converting target plays certain shielding action to X ray, still have a large amount of X ray to follow photoneutron.If with this photoneutron of neutron detector direct detection, a large amount of X ray also can enter neutron detector.Because photoneutron and X ray are produced simultaneously, and electron accelerator is to work under pulse condition, pulsewidth is the magnitude of μ s, therefore photoneutron and X ray can fly to neutron detector from optical neutron converting target in the time simultaneously at very short (usually less than 1 μ s), and namely neutron detector also can measure X ray when measuring neutron.Owing to the quantity of the X ray that enters neutron detector is very many, generally can exceed 4 magnitudes, therefore no matter how insensitive neutron detector is to X ray, X ray still can form huge signal in neutron detector, and sort signal significantly surpasses the signal that neutron forms in neutron detector, thereby the measurement to photoneutron causes severe jamming, causes neutron detector can't obtain information about photoneutron.
Known X ray and photoneutron have different qualities in material: ● X ray will be by material absorbing through after for several times collision, and its time-to-live in material has only solved the interference that X ray is measured photoneutron in the magnitude of ns; ● photoneutron generally will pass through a large amount of collisions in material just can be by material absorbing.According to the difference of material, the collision frequency of photoneutron can not wait from tens times to several thousand times, can not wait to tens ms from several μ s from the time.By the different behavioral trait of these two kinds of rays as can be known: if suitable moderation of neutrons structure is set, allow neutron in this slow body, slow down.Because it is that thermal neutron usually need to be greater than the time of several μ s that photoneutron is slowed down by fast neutron, therefore when photoneutron is thermal neutron by slowing down, the X ray pulse has not existed, measure with the detector of the thermal neutron sensitivity photoneutron after to slowing down this moment, just can obtain the information about photoneutron, and can not be subject to the interference of X ray.
An embodiment as fast-neutron detection method of the present invention, the moderation of neutrons body that photoneutron is entered made by tygon take absorption of x-rays and with the photoneutron slowing down as thermal neutron, the reusable heat neutron detector is measured thermal neutron, thereby obtains the relevant information of photoneutron.Wherein, thermal neutron detector is conventional, therefore is not described in detail at this.The area of thermal neutron detector is larger, can form the enough large solid angles that absorb thermal neutron.In other embodiments, the moderation of neutrons body also can be made by the polymkeric substance of graphite, other alkene polymer or other hydrogenous material; Thermal neutron detector then can adopt
10B,
6Other neutron-absorbing nucleic such as Li.
Fig. 2 has shown the measurement sequential of photoneutron.The duration t of X ray pulse 1 in the moderation of neutrons body as can see from Figure 2
X, being generally 4 μ s, photoneutron can't be measured within this time period.At t
XAlso has afterwards a t
dTime, this time is to recover the time of returning for the photoneutron detector from the impact of X ray pulse, this time is generally at tens μ s, such as 45 μ s.At t
dAfterwards, owing to there has not been the impact of X ray, be exactly the Measuring Time of photoneutron this moment, the t that provides among the figure
nBe exactly the Measuring Time of thermal neutron, generally at 1000 μ s, this shows, the transfer delay time of thermal neutron should be greater than the duration of X ray in slow body.T given here
X, t
d, t
nDeng all being typical case's time, can finely tune according to the situation of detector in the real work.Like this, in a recurrence interval T, the measurement that postpones photoneutron by the moderation of neutrons body is the method that thermal neutron is measured thermal neutron again with the photoneutron slowing down to avoid X ray simultaneously, obtains the relevant information of photoneutron.After next pulse begins, repeat above-mentioned steps, so just can obtain continuously the relevant information of photoneutron.
As a preferred embodiment of fast-neutron detection method of the present invention, photoneutron was present in scattering thermal neutron in the environment through the thermal neutron shield with shielding first before entering the moderation of neutrons body.Like this, just can avoid thermal neutron in the environment to the interference of neutron measurement.The thermal neutron shield also is conventional, therefore is not described in detail at this.
Fast-neutron detection method according to above-mentioned the invention provides the method for utilizing the photoneutron recognition material.As a preferred embodiment of the method, contain optical neutron converting target to produce photoneutron with the X ray bombardment first; Again with neutron collimator guiding photoneutron transmission object to be detected; Then the guiding photoneutron that passes object to be detected enters the moderation of neutrons body so that follow the X ray of photoneutron to be absorbed in the moderation of neutrons body, and photoneutron is thermal neutron by slowing down in the moderation of neutrons body simultaneously; Measure thermal neutron with the Transmission Attenuation information of acquisition photoneutron in object to be detected by thermal neutron detector at last, thereby reach the purpose of the contained material of identification object to be detected by this Transmission Attenuation information.
An embodiment who is more preferably as the method for utilizing the photoneutron recognition material, before the photoneutron that passes object to be detected enters the moderation of neutrons body, be present in scattering thermal neutron in the environment through the thermal neutron shield with shielding first, to avoid the scattering thermal neutron to the interference of neutron measurement.
According to above-mentioned fast-neutron detection method, the present invention also provides the method for utilizing simultaneously X ray and photoneutron recognition material.Fig. 3 has shown the synoptic diagram of the method for utilizing simultaneously X ray and two kinds of transmission information recognition materials of photoneutron.Because photoneutron reaction can be converted to photoneutron with useless X ray, therefore, utilizes an electron accelerator just can obtain simultaneously two kinds of rays.If adopt two kinds of detectors to come respectively detecting x-ray and photoneutron, utilize the differential declines characteristic of two kinds of rays in object, can improve the recognition capability to object to be detected.In Fig. 2, electronics bombardment electric target 11 produces X ray, and first's X ray is passing object to be detected through after the x-ray collimator 32, and is measured by X-ray detector, obtains the X ray dampening information; In the front of electric target 11, placed an optical neutron converting target 12, make the second portion X ray be converted to photoneutron at this, photoneutron is through penetrating object to be detected 33 after the neutron collimator 31; The photoneutron that passes object to be detected 33 is introduced into thermal neutron shield in the neutron detector 34 with the scattering thermal neutron in the shielding environment; Then photoneutron enters in the moderation of neutrons body in the neutron detector 34 so that follow the X ray of photoneutron to disappear, and to make the photoneutron slowing down be thermal neutron; This thermal neutron arrives the thermal neutron detector in the neutron detector 34 at last, and thus, thermal neutron detector has obtained the Transmission Attenuation information of photoneutron in object to be detected.What need to indicate is that the moderation of neutrons body surrounds thermal neutron detector fully, so in absorption of x-rays and slowing down photoneutron, the moderation of neutrons body also plays the effect of shielding to the thermal neutron of scattering in the environment.
By in conjunction with X ray and photoneutron dampening information, can realize the identification to object to be detected.Following formula (3) has reflected how two kinds of dampening informations are combined to carry out a kind of mode that material is identified.
Wherein, t is the thickness of object to be detected; μ
n(t) be the attenuation coefficient of photoneutron; μ
X(t) be the attenuation coefficient of X ray; I
n(t) be that the incident light neutron is at the intensity at object to be detected thickness t place, I
n(0) then is the not decay intensity of incident light neutron; I
X(t) be that incident X-rays is at the intensity at object to be detected thickness t place, I
X(0) then is the not decay intensity of incident X-rays.On the equation right side, denominator reflected thickness be the object of t to the attenuation multiple of X ray intensity, molecule has reflected that then the object of same thickness is to the attenuation multiple of neutron transmitted intensity; Utilize its ratio V (t), can be that the attribute of the object of t is judged to thickness, thereby realize the identification to substance classes.
Fig. 4 has shown the synoptic diagram of an embodiment of above-mentioned neutron detector.As shown in the figure, neutron detector 34 comprises thermal neutron shield 341, tygon moderation of neutrons body 342 and thermal neutron detector 343.Thermal neutron shield 341 is positioned at the porch (1) that the incident light neutron enters neutron detector 34, passes the black arrow representative of thermal neutron shield 341 from the incident light neutron of object to be detected.Thermal neutron shield 341 can be eliminated scattering thermal neutron in the environment to the impact of incident light neutron.Moderation of neutrons body 342 surrounds thermal neutron detector 343 fully, and therefore, moderation of neutrons body 342 not only can sponge the X ray in the incident light neutron, and is thermal neutron with the photoneutron slowing down, but also plays the effect of the scattering thermal neutron in the shielding environment.Slow body is generally selected has hydrogenous material, and such as the polymkeric substance of alkene, graphite also is a kind of selection.Thermal neutron detector is generally selected 3He, and 10B, 6Li etc. are the neutron-absorbing nucleic, and type photodetector is conventional, but wish that its area is larger, to form the enough large solid angles that absorb thermal neutron.
Photoneutron penetrates after the object to be detected by after the outgoing of photoneutron target, forms the incident photoneutron and enters neutron detector 34.Owing to there is the thermal neutron of scattering in the environment, can consist of and disturb, therefore before photoneutron enters detector 34 inside, at first pass through the absorption of thermal neutron shield 341, enter like this fast photoneutron that is only reflection photoneutron dampening information in material of surveying 34 inside.These fast neutrons carry out slowing down in slow body 342, obtained delay on the time simultaneously, thereby avoided the interference of X ray pulse.When neutron is thermal neutron by slowing down, just can be measured by thermal neutron detector 343, this moment, the count value of thermal neutron detector 343 just reflected the dampening information of photoneutron in object to be detected.
Although described exemplary embodiments of the present invention, should be understood that and the invention is not restricted to these embodiment, concerning the professional and technical personnel, various changes and modifications of the present invention can both realize, but these are all within the spirit and scope of claim of the present invention.
Claims (20)
1. a fast-neutron detection method is used for surveying the fast neutron with X ray, and described fast neutron is produced by pulsed X-ray bombardment optical neutron converting target, it is characterized in that the method comprises the steps:
Make described fast neutron by the moderation of neutrons body take absorb described X ray and with described Moderation of the fast neutrons as thermal neutron; With
Survey described thermal neutron with the information of acquisition about described fast neutron with thermal neutron detector,
Wherein, the transfer delay time of described thermal neutron is greater than the duration of described X ray in described moderation of neutrons body.
2. method according to claim 1 is characterized in that: described fast neutron was present in scattering thermal neutron in the environment through the thermal neutron shield with shielding first before entering described moderation of neutrons body.
3. method according to claim 1, it is characterized in that: described moderation of neutrons body is made by the polymkeric substance of hydrogenous material.
4. method according to claim 1, it is characterized in that: described moderation of neutrons body is made by alkene polymer.
5. method according to claim 1, it is characterized in that: described moderation of neutrons body is made by graphite.
6. method according to claim 1, it is characterized in that: described thermal neutron detector is selected the neutron-absorbing nucleic in following group:
3He,
10B,
6Li.
7. method according to claim 1, it is characterized in that: the area of described thermal neutron detector forms the solid angle of enough absorption thermal neutrons.
8. a method of utilizing the photoneutron recognition material comprises the steps:
Bombard optical neutron converting target to produce photoneutron with pulsed X-ray;
Guide described photoneutron transmission object to be detected; With
Survey the photoneutron that passes described object to be detected with neutron detector;
It is characterized in that:
The photoneutron that described object to be detected is passed in first guiding enter the moderation of neutrons body take absorption follow the X ray of described photoneutron and with described photoneutron slowing down as thermal neutron; With
Survey described thermal neutron with the neutron transmission dampening information of the described material of acquisition identification by the thermal neutron detector in the described neutron detector again,
Wherein, the transfer delay time of described thermal neutron is greater than the duration of described X ray in described moderation of neutrons body.
9. method according to claim 8 is characterized in that: described photoneutron was present in scattering thermal neutron in the environment through the thermal neutron shield with shielding first before by described moderation of neutrons body.
10. it is characterized in that according to claim 8 or 9 described methods: described photoneutron is by the described object to be detected of neutron collimator guiding transmission.
11. a method of utilizing simultaneously X ray and photoneutron recognition material comprises step:
Pulsed X-ray is provided;
Guide the direct transmission object to be detected of first's X ray, and pass the X ray of described object to be detected to obtain the Transmission Attenuation information of described X ray with the X-ray detector detection;
Guiding second portion X ray bombardment optical neutron converting target to be producing the photoneutron that is used for the transmission object to be detected, and surveys photoneutron by described object to be detected with the Transmission Attenuation information of acquisition photoneutron with neutron detector;
In conjunction with the Transmission Attenuation information of the Transmission Attenuation information of described photoneutron and described X ray to identify the material of described object to be detected;
It is characterized in that:
The photoneutron that described object to be detected is passed in first guiding enter the moderation of neutrons body take absorption follow the X ray of described photoneutron and with described photoneutron slowing down as thermal neutron; With
Survey described thermal neutron obtaining the Transmission Attenuation information of described photoneutron by the thermal neutron detector in the described neutron detector again,
Wherein, the transfer delay time of described thermal neutron is greater than the duration of described X ray in described moderation of neutrons body.
12. method according to claim 11 is characterized in that: described photoneutron was present in scattering thermal neutron in the environment through the thermal neutron shield with shielding first before by described moderation of neutrons body.
13. according to claim 11 or 12 described methods, it is characterized in that: described photoneutron is by the described object to be detected of neutron collimator guiding transmission.
14. according to claim 11 or 12 described methods, it is characterized in that: described first X ray is by the described object to be detected of x-ray collimator guiding transmission.
15. according to claim 11 or 12 described methods, it is characterized in that: the nucleic of described optical neutron converting target is
9Be or
2H.
16. according to claim 11 or 12 described methods, it is characterized in that: described X ray is produced by x ray generator, and described x ray generator comprises that electronics adds the bundle device.
17. a neutron detector comprises:
The moderation of neutrons body, its be used for slowing down by pulsed X-ray bombardment optical neutron converting target produce with the fast neutron of X ray to be converted into thermal neutron; With
Thermal neutron detector, it is suitable for surveying described thermal neutron with the information of acquisition about described fast neutron,
Wherein, the transfer delay time of described thermal neutron is greater than the duration of described X ray in described moderation of neutrons body.
18. neutron detector according to claim 17 is characterized in that: also comprise the thermal neutron shield, it is suitable for shielding the scattering thermal neutron that is present in the environment.
19. according to claim 17 or 18 described neutron detectors, it is characterized in that: described moderation of neutrons body surrounds described thermal neutron detector.
20. according to claim 17 or 18 described neutron detectors, it is characterized in that: described moderation of neutrons body also is suitable for shielding the scattering thermal neutron that is present in the environment.
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| CN2009102443573A CN102109607B (en) | 2009-12-29 | 2009-12-29 | Fast neutron detection method, substance identification methods and neutron detector |
| PCT/CN2010/001137 WO2011079495A1 (en) | 2009-12-29 | 2010-07-26 | Fast neutron detection method, substance discrimination method and neutron detector |
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| CN104237270A (en) * | 2014-09-26 | 2014-12-24 | 同方威视技术股份有限公司 | Method and device for imaging object through photoneutron transmission |
| CN106938124B (en) * | 2016-01-04 | 2019-10-01 | 南京中硼联康医疗科技有限公司 | The slow material of neutron |
| CN108398709A (en) * | 2017-02-08 | 2018-08-14 | 中国辐射防护研究院 | A kind of optical fiber radiation probe |
| CN106908830B (en) * | 2017-02-16 | 2018-10-02 | 中国科学院合肥物质科学研究院 | The measuring system of neutron flux is measured under a kind of intense radiation hot conditions |
| CN110779939B (en) * | 2018-07-11 | 2020-12-29 | 同方威视技术股份有限公司 | Dual-mode detection method, controller and system |
| CN114264681A (en) * | 2021-12-29 | 2022-04-01 | 清华大学 | Method and system for analyzing gold ore grade |
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| RU2406171C1 (en) * | 2007-06-21 | 2010-12-10 | Цингхуа Унивесити | Radiation to photoneutron converting target |
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2009
- 2009-12-29 CN CN2009102443573A patent/CN102109607B/en active Active
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1959387A (en) * | 2005-11-03 | 2007-05-09 | 清华大学 | Method and apparatus for recognizing materials by using fast neutrons and continuum X rays |
| CN201286191Y (en) * | 2008-06-19 | 2009-08-05 | 清华大学 | Optical neutron converting target |
Non-Patent Citations (1)
| Title |
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| JP特开平2-82188A 1990.03.22 |
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| WO2011079495A1 (en) | 2011-07-07 |
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