EP1202322B1 - Capteur pour détecter des particules neutres, en particulier des neutrons, avec un boîtier rempli de gaz - Google Patents

Capteur pour détecter des particules neutres, en particulier des neutrons, avec un boîtier rempli de gaz Download PDF

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Publication number
EP1202322B1
EP1202322B1 EP00122360A EP00122360A EP1202322B1 EP 1202322 B1 EP1202322 B1 EP 1202322B1 EP 00122360 A EP00122360 A EP 00122360A EP 00122360 A EP00122360 A EP 00122360A EP 1202322 B1 EP1202322 B1 EP 1202322B1
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EP
European Patent Office
Prior art keywords
converter
detector
layer
drift
conductive layer
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EP00122360A
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German (de)
English (en)
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EP1202322A1 (fr
Inventor
Martin Dr. Klein
Christian Dr. Schmidt
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Universitaet Heidelberg
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Universitaet Heidelberg
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Priority to DE50009131T priority Critical patent/DE50009131D1/de
Priority to EP00122360A priority patent/EP1202322B1/fr
Priority to AT00122360T priority patent/ATE286302T1/de
Priority to US10/047,556 priority patent/US7635849B2/en
Publication of EP1202322A1 publication Critical patent/EP1202322A1/fr
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J47/00—Tubes for determining the presence, intensity, density or energy of radiation or particles
    • H01J47/12—Neutron detector tubes, e.g. BF3 tubes
    • H01J47/1205—Neutron detector tubes, e.g. BF3 tubes using nuclear reactions of the type (n, alpha) in solid materials, e.g. Boron-10 (n,alpha) Lithium-7, Lithium-6 (n, alpha)Hydrogen-3
    • H01J47/1211—Ionisation chambers

Definitions

  • the invention relates to a detector for the detection of electrically neutral particles according to claim 1, and a detection method for the detection of electrically neutral particles according to claim 10.
  • thermal and cold neutrons are an important method in science (e.g. physical, chemical, biological and medical applications) and technology (e.g. non-destructive material testing). It is fundamental for all areas of application in science and technology the proof, ie the detection of such neutrons, as a result of which detectors and detection methods for neutrons have become of great economic importance in recent decades.
  • the detection of neutrons can only be achieved via a nuclear reaction using a so-called neutron converter.
  • the neutrons are captured or absorbed by the atomic nuclei of the converter, whereupon these nuclei spontaneously decay.
  • conversion products can then be detected on the basis of their ionizing effect.
  • the gas helium-3 whose atomic nuclei consist of two protons and one neutron, has mainly been used to detect neutrons.
  • This helium isotope is added to the actual counting gas of the detector in predetermined amounts in so-called gas detectors.
  • Neutrons to be detected are absorbed by the helium-3 nuclei, which subsequently decay spontaneously according to the nuclear reaction 3 He + 1 n ⁇ 3 H + 1 p + 764 keV, the tritium nucleus a quarter and the proton receives three quarters of the reaction energy.
  • these conversion products have an ionizing effect on the counting gas of such a gas detector.
  • Such neutron detectors in the form of conventional gas detectors with helium-3 as a neutron converter have considerable disadvantages.
  • a detection of neutrons over large detection areas can only be realized with the help of large, matrix-like detector arrangements, which consist of a large number of small individual detectors, due to the design restrictions of the pressure vessels.
  • the IN5 neutron spectrometer from the Laue-Langevin Institute in Grenoble has 1400 individual helium-3 neutron detectors for angle-resolved neutron detection (cf. "The yellowbook guide to neutron research facilities at ILL", Institut Laue-Langevin, Grenoble, December 1997).
  • the spatial resolution of approximately 2 cm ⁇ 10 cm and the typical acceptance of count rates of 10,000 detected neutrons per second and cm 2 of such a neutron detector are very unsatisfactory.
  • the poor resolution and the low count rate acceptance can be improved by a combination of helium-3 as a converter with a so-called microstrip detector (MSGC) to approximately 2 mm x 2 mm and one million neutrons per second and cm 2 (cf. Vellettaz et al., "Twodimensional gaseous microstrip detector for thermal neutrons ", Nuclear Instruments and Methods A 392 (1997), pages 73 to 79).
  • MSGC microstrip detector
  • Neutron scintillation detectors are also known for the detection of neutrons.
  • a solid neutron converter is admixed with a solid or liquid scintillator, for example in the form of a fine powder (cf. GB Spector et al., "Advances in terbium-doped, lithium-loaded scintillator glass development", Nuclear Instruments and Methods A 326 (1993), pages 526 to 530).
  • the conversion products that result from a neutron detection reaction deposit their energy in the scintillator.
  • the light then emitted by the scintillator is then detected in a location-sensitive manner using a suitable light detection system.
  • Such detectors have typical detection efficiencies of 20% to 40%.
  • the detector according to the invention is designed for the detection of electrically neutral particles, in particular neutrons, and other neutral particles, in particular photons.
  • the principle of detection is based on the fact that the neutral particles interact with a converter device which generates conversion products on the basis of this interaction (for example a nuclear reaction).
  • the converter device preferably contains a solid converter material.
  • the conversion products subsequently ionize the counting gas or the gas with which the detector housing is at least partially filled and which at least partially surrounds the converter device.
  • they are fed to a reading device under the influence of an electrical drift field.
  • the detector has a drift field generation device, which can in particular be provided separately from the converter device and the readout device.
  • the drift field generating device can also be included to generate the drift field, so that the drift field generation device can be implemented in particular by a special configuration of the converter and readout device.
  • the at least one converter device is designed to be charge-transparent, ie it has a high transmission coefficient for the electrically charged particles. The electrically charged particles can preferably pass through the converter device while maintaining their location information.
  • the converter device has a plurality of passages, preferably arranged in a matrix, for the electrically charged particles.
  • the passages can be designed, for example, as geometrically designed openings or holes in the converter device.
  • a passage can also be formed by a charge-transparent zone which has a small interaction cross-section for the electrically charged particles in comparison with the adjacent material, so as to have a high transmission coefficient for the charged particles.
  • the converter device particularly preferably has a regular matrix of circular openings.
  • the passages have a minimum diameter between 10 ⁇ m to 1000 ⁇ m, preferably 25 ⁇ m to 500 ⁇ m and a minimum distance from one another of 10 ⁇ m to 500 ⁇ m, preferably 15 ⁇ m to 300 ⁇ m.
  • the detector has a multiplicity, preferably 2 to 20, most preferably 10, of converter devices arranged cascaded (one behind the other).
  • the converter devices can in each case be spaced apart from one another in a stack-like manner in the detector housing, so that the counting gas is located between the converter devices.
  • Due to the charge transparency of the converter devices the charged particles generated by the conversion products, the detection of which enables the detection of the neutral particles, can be moved through the cascade of the converter devices to the readout device by means of the drift field.
  • the use of cascaded converter devices in the detector according to the invention accordingly enables an enormous increase in the available interaction area for the electrically neutral particles and thus a considerable increase in the detection sensitivity.
  • a region of the converter device which is active for the conversion of the electrically neutral particles is preferably designed in a planar manner, in particular in a planar manner, and is preferably arranged essentially perpendicularly in the drift field.
  • This surface or layer-like structure of the converter device enables a further improvement of the surface to volume ratio of the converter device. This is because, although the (solid) converter material is typically sensitive to the neutral particles to be detected in the entire volume, the conversion products often only have a relatively short range in the converter material and can therefore only escape from it if they are sufficiently close to its surface , to achieve a high detection sensitivity, it is advantageous to have the largest possible converter area available for detection for a given converter volume or mass.
  • the converter device is arranged substantially vertically in the drift field. Accordingly, the average field direction of the drift field is advantageously essentially parallel to the surface normal of the flat converter device. An inclined arrangement of the converter device is also possible as long as the plane of the flat converter device does not run parallel to the drift field.
  • the drift field generating device has a flat, optionally structured drift electrode in order to generate the drift field between the drift electrode and the readout device.
  • the drift electrode is negatively biased with respect to the readout device.
  • the drift electrode can be dispensed with if its function is taken over by an electrode layer of the converter device.
  • the converter device comprises a first and second conductive layer, which are electrically insulated from one another by an insulator layer arranged between them, and at least one converter layer preferably arranged on the first and / or second conductive layer.
  • the converter device thus has a layer structure.
  • a plastic film in particular polyimide film, is used as the insulator layer.
  • Kapton films have proven particularly effective (Kapton is a trademark of DUPONT).
  • the two conductive layers are electrically insulated from one another by this insulating layer.
  • the conductive layers are preferably metal layers which have been applied directly to the insulating layer by a coating process. Copper layers are particularly suitable for the conductive layers.
  • the layer-like converter device further comprises a converter layer, which is preferably arranged on the surface of the first and / or second conductive layer facing away from the insulator layer. Equally, however, the converter layer can also be arranged between one of the, in particular, thin and structured conductive layers and the insulator layer his. If the converter layer can be designed as a conductive layer, an additional conductive layer of the converter device can be dispensed with.
  • Such a particularly preferred layer-like converter device can be produced by means of so-called GEM (gas electron multiplier) films, as described, for example, in US Pat. No. 6,011,265 and in the publication by F. Sauli in Nucl. Inst. And Methods A 386 (1997) pages 531 to 543.
  • GEM gas electron multiplier
  • These GEM foils described in the specified publications are Kapton foils coated on both sides with copper, which were developed by F. Sauli at CERN in 1997.
  • a regular hole structure is etched into these GEM foils by means of a photolithographic process, the top and bottom surfaces of the foils not being electrically connected to one another.
  • the layered converter device described differs from the GEM foils proposed by F. Sauli in particular in the converter layer additionally present.
  • the GEM films in the applications discussed in the cited documents are operated exclusively in a gas amplification mode. Field strengths of this type are built up between the two conductive layers by means of suitable electrical circuitry, so that the primary electrons increase in avalanches, so that the foils represent a "gas electron multiplier" (GEM).
  • GEM gas electron multiplier
  • the converter devices according to the present invention are preferably not operated in such a gas amplification mode, but rather only the charge-transparent property of the GEM films exploited.
  • the converter device is designed such that a potential difference that supports the drift process can be applied between the first and the second conductive layer.
  • the first and second conductive layers of the converter device are electrically connected to one another via a converter field generating device.
  • the converter field generation device enables the generation of an electrical drift field, which can act in addition to the drift field generated by the drift field generation device. This ensures that the electrically charged particles can be passed efficiently through the converter device.
  • the (fixed) converter layer preferably contains a neutron converter layer, so that the detector is suitable for the detection of neutrons, the neutron converter layer containing in particular lithium-6, boron-10, gadolinium-155, gadotinium-157 and / or uranium-235. If UV and / or X-ray photons are to be detected as neutral particles, Csl in particular can be considered as the material for the photon converter layer.
  • the converter layer has a layer thickness of 0.1 ⁇ m to 10 ⁇ m, preferably for a neutron converter layer consisting essentially of boron-10 between 0.5 ⁇ m to 3 ⁇ m, most preferably approximately 1 ⁇ m
  • the first and second conductive layer has a layer thickness of 0.1 ⁇ m to 20 ⁇ m, preferably 0.2 ⁇ m to 10 ⁇ m
  • the insulator layer has a layer thickness of 10 ⁇ m to 500 ⁇ m, preferably 25 ⁇ m to 100 ⁇ m.
  • the converter device for a detector for the detection of electrically neutral particles, in particular neutrons comprises a first and second conductive layer which are electrically insulated from one another by an insulator layer arranged between them, and at least one (fixed) converter layer preferably arranged on the first and / or second conductive layer , wherein the converter device has a plurality of passages, preferably arranged in a matrix, for electrically charged particles.
  • a converter layer can be used in conjunction with a conventional gas detector simple and highly sensitive detection of neutral particles, especially neutrons, can be used.
  • the converter device is introduced into the drift field of the gas detector. It is particularly preferred not to use a single converter device, but rather a “stack” of cascaded converter devices, as a result of which the detection sensitivity can be increased enormously.
  • the converter device preferably contains a neutron converter material, so that the converter device is designed for a detector for the detection of neutrons, the neutron converter material in particular containing lithium-6, boron-10, gadolinium-155, gadoliniuim-157 and / or uranium-235.
  • the neutron converter layer preferably contains at least one neutron converter material mentioned above.
  • the converter device according to the invention can in particular be produced from a so-called GEM film, to which an additional converter layer is applied.
  • a boron-10 layer can be evaporated onto a GEM film by means of electron beam evaporation of a boron-10 powder or granulate.
  • Claim 10 describes a detection method for the detection of electrically neutral particles, in particular neutrons, according to the present invention.
  • the charge-transparent design of the converter device allows the charged particles to be passed through the converter device (s) without losing their location information. It follows from the charge transparency that the place of production of the charged particles in the counting gas is mapped or directed undistorted by the converter device (s) to the preferably location-sensitive reading device.
  • FIG. 1 shows a highly schematic sectional view
  • FIG. 2 shows schematic perspective views of a detector for the detection of neutrons according to one embodiment of the invention. The construction of the detector is first described with reference to FIGS. 1 and 2.
  • a gas (not shown) or counting gas is introduced via a gas supply 12.
  • a gas discharge 14 is also provided for venting the detector housing. All counting gases common for gas detectors can be used. It is only necessary that the conversion products formed in the nuclear reaction to be described later have an ionizing effect on the gas. Mixtures of argon with one or more of the components CO 2 (10-90% content), CF 4 , dimethyl ether, isobutane and CH 4 have proven to be particularly suitable. In contrast to conventional helium-3 neutron detectors, it is not necessary that the counting gas be kept under high pressure, but can advantageously be introduced into the detector housing 10 under normal pressure.
  • An entry window 16 is embedded in the top of the detector housing 10. Since the detector shown is preferably not operated with an increased counting gas pressure, the entrance window 16 can be made very thin, so that it has only a small cross section for the absorption of the incident neutrons. In addition, the incident neutrons are deflected only very slightly through the thin entrance window.
  • a drift electrode 18 Arranged in or near the entry window 16 in the detector housing 10 is a drift electrode 18, which is part of a drift field generating device. An electrical drift field for electrically charged particles can be applied between the drift electrode 18 and a read-out device 19 to be described later, a negative voltage being applied to the drift electrode 19 with respect to the read-out device 19.
  • a layer 20 of a solid neutron converter for example a boron-10 layer, can optionally be attached to the drift electrode 18.
  • the drift field generating device comprises the drift electrode 18 as the first electrode and the readout device as the (structured) second electrode.
  • the drift electrode 18 can also be taken over by a conductive layer of the converter device 22 adjacent thereto, so that the drift electrode 18 can be dispensed with.
  • the converter devices 22 are essentially located in the drift field generated between the drift electrode 18 and the readout device 19.
  • the converter devices 22 are preferably constructed in layers and consist, for example, of a so-called GEM film (see above), which is coated on one or both sides with a fixed converter layer 24 - here a neutron converter layer made of boron-10.
  • the converter layer 24 is preferably applied essentially homogeneously, but the converter layer 24 is also only in regions or can be applied in different layer thicknesses.
  • Each of the converter devices 22 comprises an insulator layer 26, for example a polyimide film.
  • Kapton films have proven particularly successful (Kapton is a trademark of DUPONT).
  • the insulator layer 26 is coated on both sides with a conductive material, for example copper, so that it is arranged between a first conductive layer 28 and a second conductive layer 30.
  • the two electrically conductive layers 28 and 30 are electrically insulated from one another by the insulator layer 26.
  • the converter device 22 has a multiplicity of passages 32 arranged in a matrix, through which electrically charged particles can drift in a manner to be described. The arrangement pattern of these passages 32, which the converter devices 22 pass through in the normal direction of the layer plane, is shown schematically in FIG.
  • the GEM foils gas electron multiplier foils described in the cited documents are concerned essentially around Kapton foils coated with copper on both sides, which were developed by F. Sauli at CERN in 1997. A regular hole structure is etched into these GEM foils using a photolithographic process, the top and bottom sides of the foils not being electrically connected to one another.
  • the readout device 19 is arranged opposite the entry window 16 and the drift electrode 18 in the detector housing 10 such that the cascaded converter devices 22 are arranged in a stack-like manner therebetween.
  • the surface normals of the entry window 16, the drift electrode 18, the converter devices 22 and the readout device 19 preferably coincide essentially.
  • the mean field direction of the electrical drift field between adjacent converter devices 22 is essentially perpendicular to the layer planes of the converter devices 22, so that it follows the longitudinal axis of the hole-like passages 32.
  • the drift electrode 18 and the readout device 19 are spaced apart from the converter devices 22, the space being filled by the counting gas.
  • reading device 19 All conventional detector systems with which charged particles, in particular electrons, can be detected can be used as reading device 19.
  • comb-like or interdigital intermeshing electrode structures can be used as readout device 19, which are shown schematically in FIG. 2a and FIG. 2b.
  • multi-wire gas chambers or similar detectors can also be used.
  • detection electronics not shown.
  • FIG. 2c In addition to comb-like and interdigital readout structures (cf. FIGS. 2a and 2b), which only provide the location information in one dimension, readout structures which are crossed to one another and which provide a spatial resolution in two spatial dimensions are equally interesting.
  • a modified read-out device 19 is shown schematically in FIG. 2c.
  • two read-out structures crossed to one another are arranged on the top and bottom of a carrier plate.
  • ring-shaped read-out structures are interesting, since they integrate over the entire azimuth angle and the entire one
  • FIG. 2d Such an reading device 19 ′′ with an annular read-out structure is shown in FIG. 2d.
  • FIG. 4 (a) is a schematic sectional view of a preferred support device 36, with which a large number of converter devices 22 arranged in cascade fashion can be attached in the detector housing 10.
  • the carrying device 36 has four fastening supports 38, for example made of a ceramic material, which are fixed to a base plate 40.
  • a corner section of a substantially rectangular clamping frame 42 is attached to each of the fastening supports 38.
  • the tenter frame 42 has an upper 44 and a lower 46 frame member.
  • the frame elements 44 and 46 consist of a conductive material, for example stainless steel. Between the frame elements 44, 46, one of the converter devices 22 is held under such a mechanical tensile stress that it is fixed essentially smoothly and without folds. Between the respective layer sides of the converter device 22 and the frame elements 44 and 46, U-shaped insulating elements 48, for example Kapton foils, are introduced, which only allow direct contact between the frame elements 44, 46 and the respective layer sides of the converter device 22. As a result, the converter device can be held in the clamping frame 42 such that its upper frame element 44 is electrically connected to the first conductive layer 24 and its lower frame element 46 to the second conductive layer, while the frame elements 44 and 46 are insulated from one another.
  • the neutrons to be detected are at least partially absorbed by the converter layers 24 of the converter devices 22. If the converter layer 24 consists essentially of isotopically pure boron-10, which has been found to be particularly suitable, the boron-10 nucleus spontaneously breaks down into an ⁇ -particle and a lithium-7 nucleus after absorption of the neutron. Because the momentum of the absorbed neutron is comparatively is small and therefore negligible, the ⁇ -particle and the lithium-7 core will fly apart in opposite directions due to the conservation of momentum. At least one of these conversion products will therefore move away from the layer level of the converter device 22 or from the converter layer 24 and ionize the counting gas. As a result, free electrons in particular are generated in the counting gas.
  • Such ionization traces of the conversion products are shown schematically in FIG.
  • the primary electrons generated by this process represent the signal actually to be detected.
  • the charge cloud of the primary electrons is subtracted from the electrical drift field, which is applied between the drift electrode 18 and the readout device 19, in the direction of the readout device 19.
  • the generated electrons have to pass one or more of the conversion devices 22 in order to reach the readout device 19. This is made possible by the charge transparency of the converter devices 22, which allows the primary electrons to reach the readout device 19 without losing their location information, so that by means of a spatially resolved detection of these electrons by the readout device 19, the ionization site of the counting gas - and thus the Absorption site of the neutron to be detected - can be closed.
  • GEM films have charge-transparent properties when suitably connected electrically.
  • the electric field lines of the drift field constrict in the area of the passages 32 of the converter devices 22 when a potential difference supporting the drift process is applied between the first conductive layer 28 and the second conductive layer 30.
  • the electrical field lines expand symmetrically again.
  • a primary electron which was generated by the ionizing effect of a conversion product in the counting gas, follows the course of one of the field lines shown in FIG. 3 and can thus pass through the passage 32 upon receipt of its location information by one or more converter devices 22 are "smuggled".
  • the described construction of the embodiments of the detector for neutrons according to the invention advantageously allows the use of a fixed neutron converter.
  • Such solid neutron converters for example converter layers made of boron-10, are much more suitable for efficient detection of neutrons for fundamental reasons, since the density of the converter atoms in a solid neutron converter is about 1000 times greater than in gaseous converters and thus a considerably higher cross section for neutrons.
  • the use of solid converter materials leads to detection problems of the loaded conversion products. To a large extent, these already get stuck in the converter material itself and can only release their energy to a surrounding detection medium (for example a counting gas) to a limited extent. Only conversion products originating from surface layers can be proven effectively.
  • the advantage of a tightly packed neutron absorber in the form of a solid body is therefore due to the lack of conventional neutron detectors The probability of the charged fragments escaping into the surrounding detection medium is nullified.
  • the counting gas can be used under normal pressure, so that no pressure vessel is necessary. Operation at normal pressure in turn enables the construction of detectors of any size and with various shapes.
  • neutron detectors which comprise converter devices 22 arranged in cascade, has proven to be particularly advantageous. This makes it possible to provide a particularly favorable ratio of the surface of a converter layer to its converter volume.
  • the use of fixed neutron converters regularly leads to problems with the detection of the loaded conversion products. A large part of these conversion products already get stuck in the fixed converter itself and can only transfer their energy to a surrounding detection medium, such as e.g. deliver a counting gas. Only conversion products originating from surface layers can be proven effectively. Under certain circumstances, the advantage of a densely packed neutron absorber in the form of a solid body can thus be negated by the low probability of the conversion products escaping into the surrounding detection medium.
  • the charge-transparent design of the converter devices 22 according to the invention makes it possible to use a plurality of converter devices 22 in a cascade fashion in order to duplicate or improve the detection efficiency.
  • the actual ionization signal, ie the primary electrons formed can penetrate the converter devices 22 due to the transparency of the charge, while maintaining their location information, so that the entire electron signal can be used to detect the absorbed neutrons.
  • boron-10 is used as the converter material in the converter layers 24 of a detector according to the invention, which comprises 10 cascaded converter devices 22 coated on both sides, one obtains For example, a detection efficiency of 75% for 2 meV neutrons, 50% for 25 meV neutrons, 35% for 100 meV neutrons and about 25% for 200 meV neutrons.
  • the primary charge which is generated in the cascade of the charge-transparent converter devices 22, can - as described - be detected by any electrode array as an embodiment of the read-out device 19. Due to the type and shape of the read-out device 19, the spatial resolution capacity is obtained in a simple manner. The shape and duration of typical charge pulses result in a typical acceptance rate of around 10 million neutrons per second and pixel. The size of a pixel and thus the spatial resolution is limited to about 2 mm x 2 mm by the range of the loaded conversion products at normal count rates under normal pressure. Thus, the detector concept according to the invention presented here has an approximately 1000 times greater rate acceptance per pixel and a 10 times better linear spatial resolution than previous helium-3 gas detectors for neutrons.
  • the detector according to the invention makes it possible to dispense with the use of materials with a high atomic number. This results in an inherent insensitivity to gamma and X-rays. If, for example, boron-10 is used as an active converter material, the signals can also be discriminated against the remaining X-ray and gamma background due to the shape of the pulse height spectrum.
  • the detector according to the invention in its embodiment as a neutron detector is consequently insensitive to gamma and X-radiation.
  • the converter devices 22 can in particular be produced in a simple manner from conventional GEM films in which one or preferably both surfaces of the GEM film are provided with converter layers 24.
  • a layer thickness of approx. 3 ⁇ m of the boron-10 layer represents an optimum for the ratio of the neutron absorption probability and the probability of escape of the loaded conversion products from the fixed converter into the counting gas, since the maximum range of the loaded conversion products in boron-10 only is about 3.5 ⁇ m.

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  • Chemical & Material Sciences (AREA)
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Claims (10)

  1. Capteur pour détecter des particules électriquement neutres, en particulier des neutrons avec
    - un boîtier de capteur (10) rempli au moins par zones de gaz de comptage,
    - au moins un dispositif de convertisseurs (22) disposé dans le boîtier de capteur (10) qui génère des produits de conversion du fait d'une absorption des particules neutres à détecter, les produits de conversion générant dans le gaz de comptage des particules électriquement chargées,
    - au moins un dispositif de lecture (19) pour la détection des particules électriquement chargées et
    - au moins un dispositif de constitution d'un champ de dérive (18) pour constituer dans au moins une zone de volume du gaz de comptage un tel champ de dérive électrique pour les particules électriquement chargées que les particules électriquement chargées dérivent au moins partiellement vers le dispositif de lecture (19),
       dans lequel le dispositif de convertisseurs (22) est disposé de telle façon dans le boîtier de capteur (10) qu'il soit au moins partiellement traversé par le champ de dérive, le dispositif de convertisseurs (22) comprend une première couche conductrice (28) et une deuxième couche conductrice (30), qui font l'objet d'une isolation électrique réciproque par une couche isolante (26) disposée entre elles, ainsi qu'au moins une couche de convertisseurs (24) disposée de préférence sur la première couche conductrice (28) et/ou sur la deuxième couche conductrice (30) et le dispositif de convertisseurs (22) est conçu de telle façon qu'une différence de potentiel entre la première couche conductrice (28) et la deuxième couche conductrice (30), qui assiste l'opération de dérive, puisse être appliquée, caractérisé en ce que le dispositif de convertisseurs comprend une pluralité de passages (32) pour les particules électriquement chargées, qui sont de préférence disposés à la manière d'une matrice, et en ce que le capteur comprend une pluralité de dispositifs de convertisseurs (22) disposés en cascade.
  2. Capteur selon la revendication 1, caractérisé en ce que la différence de potentiel pouvant être appliquée entre la première couche conductrice (28) et la deuxième couche conductrice (30) et qui assiste l'opération de dérive est conçue de telle façon que les produits de conversion traversent les dispositifs de convertisseurs respectifs (22) avec un effet renforcé qui est sensiblement égal à 1.
  3. Capteur selon la revendication 1 ou 2, caractérisé en ce que les passages (32) ont un diamètre minimal situé entre 10 µm et jusqu'à 1000 µm, de préférence de 25 µm à 500 µm, et un espacement minimal de 10 µm à 500 µm, de préférence de 50 µm à 300 µm.
  4. Capteur selon l'une quelconque des revendications précédentes, caractérisé en ce que le capteur comprend de préférence un nombre de dispositifs de convertisseurs (22) disposés en cascade qui est de 2 à 20 et qui est de la manière la plus préférée de 10.
  5. Capteur selon l'une quelconque des revendications précédentes, caractérisé en ce qu'une zone du dispositif de convertisseurs (22) qui est active pour la conversion est conçue de manière plane et est de préférence disposée sensiblement dans le sens perpendiculaire dans le champ de dérive.
  6. Capteur selon l'une quelconque des revendications précédentes, caractérisé en ce que le dispositif de constitution d'un champ de dérive (18) comprend une électrode de dérive (18) plane et éventuellement structurée qui sert à produire le champ de dérive (18) entre l'électrode de dérive (18) et le dispositif de lecture (19).
  7. Capteur selon l'une quelconque des revendications précédentes, caractérisé en ce que la première couche conductrice (28) et la deuxième couche conductrice (30) sont reliées électriquement avec un dispositif de constitution de champ de convertisseurs.
  8. Capteur selon l'une quelconque des revendications précédentes, caractérisé en ce que la couche de convertisseurs (24) est une couche de convertisseurs de neutrons, qui contient en particulier du lithium 6, du bore 10, du gadolinium 155, du gadolinium 157 et/ou de l'uranium 235.
  9. Capteur selon l'une quelconque des revendications précédentes, caractérisé en ce que la couche de convertisseurs (24) a une épaisseur de couche de 0,1 µm à 10 µm, de préférence, pour une couche de convertisseurs de neutrons se composant pour l'essentiel de bore 10, entre 0,5 µm et 3 µm, et de la manière la plus préférée d'environ 1 µm, en ce que la première couche conductrice et la deuxième couche conductrice ont une épaisseur de couche de 0,1 µm à 20 µm, de préférence de 0,2 µm à 10 µm, et en ce que la couche d'isolation a une épaisseur de couche de 10 µm à 500 µm, de préférence de 25 µm à 100 µm.
  10. Procédé de détection pour détecter des particules électriquement neutres, en particulier des neutrons, avec les étapes suivantes :
    - Interception des particules électriquement neutres à détecter à l'aide d'une pluralité de dispositifs de convertisseurs (22) qui sont disposés en cascade et qui génèrent des produits de conversion lors de l'absorption des particules neutres ;
    - Constitution de particules électriquement chargées dans un gaz de comptage à l'aide des produits de conversion ;
    - Evacuation, dans un champ de dérive électrique, des particules électriquement chargées vers un dispositif de lecture (19), alors que le champ de dérive est assisté par un potentiel électrique appliqué entre une première couche conductrice (28) et une deuxième couche conductrice (30) du dispositif de convertisseurs (22), et alors que les particules électriquement chargées sont au moins partiellement dirigées à travers une pluralité de passages (32) se trouvant dans le dispositif de convertisseurs (22) et qui sont de préférence disposés à la manière d'une matrice et
    - Détection des particules électriquement chargées dans le dispositif de lecture (19).
EP00122360A 2000-10-24 2000-10-24 Capteur pour détecter des particules neutres, en particulier des neutrons, avec un boîtier rempli de gaz Expired - Lifetime EP1202322B1 (fr)

Priority Applications (4)

Application Number Priority Date Filing Date Title
DE50009131T DE50009131D1 (de) 2000-10-24 2000-10-24 Detektor zum Nachweis elektrisch neutraler Teilchen, insbesondere Neutronen, unter Benutzung eines mit einem Zählgas gefüllten Gehäuses
EP00122360A EP1202322B1 (fr) 2000-10-24 2000-10-24 Capteur pour détecter des particules neutres, en particulier des neutrons, avec un boîtier rempli de gaz
AT00122360T ATE286302T1 (de) 2000-10-24 2000-10-24 Detektor zum nachweis elektrisch neutraler teilchen, insbesondere neutronen, unter benutzung eines mit einem zählgas gefüllten gehäuses
US10/047,556 US7635849B2 (en) 2000-10-24 2001-10-23 Detector

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP00122360A EP1202322B1 (fr) 2000-10-24 2000-10-24 Capteur pour détecter des particules neutres, en particulier des neutrons, avec un boîtier rempli de gaz

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EP1202322A1 EP1202322A1 (fr) 2002-05-02
EP1202322B1 true EP1202322B1 (fr) 2004-12-29

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US (1) US7635849B2 (fr)
EP (1) EP1202322B1 (fr)
AT (1) ATE286302T1 (fr)
DE (1) DE50009131D1 (fr)

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US7157718B2 (en) * 2004-04-30 2007-01-02 The Regents Of The University Of Michigan Microfabricated radiation detector assemblies methods of making and using same and interface circuit for use therewith
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Also Published As

Publication number Publication date
US20020139935A1 (en) 2002-10-03
DE50009131D1 (de) 2005-02-03
ATE286302T1 (de) 2005-01-15
EP1202322A1 (fr) 2002-05-02
US7635849B2 (en) 2009-12-22

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