EP3984336A1 - Cibles liquides pour la production de particules nucléaires - Google Patents
Cibles liquides pour la production de particules nucléairesInfo
- Publication number
- EP3984336A1 EP3984336A1 EP20734653.7A EP20734653A EP3984336A1 EP 3984336 A1 EP3984336 A1 EP 3984336A1 EP 20734653 A EP20734653 A EP 20734653A EP 3984336 A1 EP3984336 A1 EP 3984336A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- shell
- target
- particles
- target material
- rotation
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000002245 particle Substances 0.000 title claims abstract description 111
- 239000007788 liquid Substances 0.000 title claims abstract description 103
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 20
- 239000013077 target material Substances 0.000 claims abstract description 72
- 230000003993 interaction Effects 0.000 claims abstract description 9
- 238000005119 centrifugation Methods 0.000 claims abstract description 8
- 239000012530 fluid Substances 0.000 claims abstract description 7
- 229910052744 lithium Inorganic materials 0.000 claims description 58
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 56
- 239000000463 material Substances 0.000 claims description 13
- 238000000034 method Methods 0.000 claims description 9
- 238000006243 chemical reaction Methods 0.000 description 16
- 238000010586 diagram Methods 0.000 description 9
- 239000007787 solid Substances 0.000 description 9
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 6
- 229910052750 molybdenum Inorganic materials 0.000 description 6
- 239000011733 molybdenum Substances 0.000 description 6
- 238000001816 cooling Methods 0.000 description 4
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- 238000002560 therapeutic procedure Methods 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 2
- 208000019155 Radiation injury Diseases 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 150000001572 beryllium Chemical class 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 229910052796 boron Inorganic materials 0.000 description 2
- 238000003889 chemical engineering Methods 0.000 description 2
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- 150000003839 salts Chemical class 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
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- ZOXJGFHDIHLPTG-BJUDXGSMSA-N Boron-10 Chemical compound [10B] ZOXJGFHDIHLPTG-BJUDXGSMSA-N 0.000 description 1
- 206010028980 Neoplasm Diseases 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 1
- 230000009471 action Effects 0.000 description 1
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- 238000004458 analytical method Methods 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
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- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 125000004435 hydrogen atom Chemical class [H]* 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
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- 238000009659 non-destructive testing Methods 0.000 description 1
- 238000009377 nuclear transmutation Methods 0.000 description 1
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- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
- 229910052724 xenon Inorganic materials 0.000 description 1
- FHNFHKCVQCLJFQ-UHFFFAOYSA-N xenon atom Chemical compound [Xe] FHNFHKCVQCLJFQ-UHFFFAOYSA-N 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
- H05H6/00—Targets for producing nuclear reactions
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21G—CONVERSION OF CHEMICAL ELEMENTS; RADIOACTIVE SOURCES
- G21G4/00—Radioactive sources
- G21G4/02—Neutron sources
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
- H05H3/00—Production or acceleration of neutral particle beams, e.g. molecular or atomic beams
- H05H3/06—Generating neutron beams
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
- A61N5/00—Radiation therapy
- A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
- A61N2005/1085—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy characterised by the type of particles applied to the patient
- A61N2005/109—Neutrons
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
- H05H6/00—Targets for producing nuclear reactions
- H05H2006/007—Radiation protection arrangements, e.g. screens
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/10—Nuclear fusion reactors
Definitions
- the present invention relates to liquid targets for the production of nuclear particles and to systems incorporating such targets. It relates in particular to targets for the generation of neutron fields.
- nuclear particles e.g. neutrons, protons, alpha particles
- a specific nuclear reaction resulting from the interaction of a beam of incident particles that are already known to be produced (e.g. protons, deuterons or other nuclei atomic) on targets formed by a material allowing the specific nuclear reaction.
- BNCT synchrom for “Boron Neutron Capture Therapy”
- a neutron energy for the irradiation of the patient of between approximately 0.5 eV and 10 keV.
- the nuclear reaction 7 Li (p, n) 7 Be of protons with an energy E> 1.88 MeV on lithium used as target material is known in particular.
- a proton (or a deuton) collides with a lithium nucleus ( 7 Li) to form a beryllium nucleus ( 7 Be) with ejection of a neutron of energy between 25 keV and 785 keV.
- a moderator is then used to reduce the energy of the neutrons.
- the 7 Be nucleus formed during the nuclear reaction is unstable with a half-life of 53 days; it decays by electronic capture, emitting a gamma of 478 keV, harmful from a radiation protection point of view. We therefore seek to control the quantity of 7 Be present in the target.
- the depth of penetration into the target material may be greater or lesser. In the case of low energies, this penetration is low and the energy transfer of the beam takes place in the subsurface which creates a significant heating of the target material. There is therefore an interest in working with thin target materials to distribute part of the heat provided by the beam of incident particles in the target material. As solid thin films present problems of stability and deterioration under beam, “liquid” targets represent an interesting solution for high powers.
- the reaction 7 Li (p, n) 7 Be described above can be obtained from a target based on solid lithium.
- a target comprises a thin layer of solid lithium arranged on a support and on which strikes a beam of particles originating from a particle accelerator.
- the integrity of the layer and its adhesion to the support must be guaranteed by the continuous evacuation of a thermal power of more than 3 kW / cm 2 .
- Lithium having a low melting point (180.5 ° C) the lifespan of a solid lithium-based target is limited in time and the target must therefore be changed very regularly.
- Liquid lithium-based targets have also been developed. Liquid lithium can withstand higher temperatures compared to solid lithium. As a result, compared to a solid lithium-based target, the problems associated with the integrity of the layer, its resistance to the support and its maintenance at very low temperature ( ⁇ 180 ° C.) are solved.
- targets based on liquid lithium are described in particular in Halfon et al. [Ref 1] and Kobayashi et al. [Ref 2]
- the targets based on liquid lithium described in the aforementioned references comprise a circulation of liquid lithium in closed conduits with, at the level of the arrival of the particle beam, an open and curved zone on which the lithium forms a web of several hundred microns up to 1.5 mm.
- the lithium flow rate in the pipes is sufficient to establish a high speed scrolling of the layer of liquid in front of the beam (7 m / s in the case of the target disclosed in [Ref 1], up to 30 m / s in the case of the target disclosed in [Ref 2]), so that the temperature of the web remains acceptable to limit the evaporation of lithium.
- the 7 Be produced by the reaction 7 Li (p, n) 7 Be contributes to creating a not insignificant quantity of a radioactive species ( 7 Be); this results in a possible activation of the loop materials containing the circulating lithium.
- a solution to overcome the problems of radiotoxicity of the 7 Be produced, described for example in [Ref 1], is to use a cold trap at the level of the lithium reservoir to condense the 7 Be in the solid state in the reservoir. This configuration involves protecting the reservoir more particularly from a radiological point of view.
- An objective of the present description is to provide a new liquid target which allows better compactness of the installation and a reduced quantity of target material, in particular for the generation of neutron fields, while allowing excellent heat removal.
- the present description relates to a liquid target for the production of nuclear particles, comprising:
- a shell formed by a surface of revolution and mounted in rotation about an axis of rotation coincident with an axis of revolution of said shell;
- a reservoir comprising a target material in the liquid state in operation, said target material being suitable for the production of said nuclear particles;
- a target material lifting device configured to drive, in operation, the target material from the reservoir to an upper surface of the hull
- a gutter formed along an outer perimeter of the hull and configured to receive, in operation, droplets from a web of target material induced by centrifugation on said upper surface of the hull, when rotating shell,
- At least one return duct forming a fluid connection between said gutter and said reservoir
- an inlet duct configured to bring, in operation, a beam of accelerated particles into an impact zone of said particles accelerated with the shell, said impact zone being located on said upper surface of the shell, the interaction of said particles accelerated with target material circulating on said upper surface of the shell generating said nuclear particles.
- a target according to the present description thus makes it possible to obtain, by centrifugation, a sheet of target material in the liquid state, formed in a device operating in closed circulation. This results, in particular compared to the liquid targets described in the state of the art, a reduction in the bulk of the installation necessary for the operation of the target and a limitation of the volume of liquid required.
- the impact zone of the particles accelerated with the target is a zone situated on the upper surface of the shell
- a sheet of target material is generated in the target according to the present description. with which the accelerated particles directly interact.
- the sheet of target material thus generated on the upper surface of the shell is sufficiently thick so that excellent heat dissipation is obtained both by conduction in the shell which supports it and by convection via the liquid; it is therefore possible to withstand high beam powers of incident particles without degradation and to produce higher nuclear particle fluxes.
- the target according to the present description can operate, in use, in a "horizontal" configuration, that is to say with an axis of rotation of the shell arranged vertically. Such an arrangement allows the target material in the liquid state projected in the gutter to be directly injected back into the reservoir by gravity without using additional energy.
- nuclear particle is understood to mean any particle which can be produced by a nuclear reaction, for example neutrons, protons, alpha particles.
- accelerated particle beam in the present description is understood to mean particles, for example protons or deuterons, which bombarded on a given target material, make it possible to produce nuclear particles.
- the target material comprises fluids which, in operation and at very low temperatures, are in the liquid state, such as hydrogen, nitrogen, argon or xenon.
- the target material comprises materials, for example metallic lithium or fluorinated molten salts, which in operation and at high temperature, are in the liquid state.
- the liquid target is suitable for the generation of neutron fields and the target material is for example metallic lithium which, in operation, is in the liquid state.
- the target In the case of neutron production, the target is generally surrounded by a neutron moderator; the compactness of the target according to the present description makes it possible to keep all the lithium in a thermal neutron zone backscattered by the moderator around him. This allows the transmutation of 7 Be by the reaction 7 Be (n th , p) 7 Li, the product obtained being none other than the initial 7 Li. This eliminates the need for a 7 Be trap and self-regeneration of the liquid lithium is obtained.
- the shell is formed from molybdenum or from a molybdenum-based alloy (for example TZM based on molybdenum (99.5%) with zirconium and titanium), or steel or a combination of these two materials.
- a molybdenum-based alloy for example TZM based on molybdenum (99.5%) with zirconium and titanium
- different materials can be used for the shell, the materials being chosen not to exhibit a reaction with the target material in the liquid state at the temperature of use.
- the shell can be formed from carbon-based materials for target materials including molten fluorinated salts.
- the surface of revolution forming said shell comprises at least a first frustoconical portion, the apex of which is located on the axis of rotation and which has a given apex half-angle.
- Other shapes can be considered for said first portion, such as for example a shape having a curved profile along a meridian plane (or plane containing the axis of revolution).
- the half-angle at the top of said frustoconical portion is between 0 ° and 90 °, advantageously between 40 ° and 50 °.
- a radius r of the first portion (for example frustoconical or curved) at a given point is defined in a plane perpendicular to the axis of rotation of the shell, by a distance between said axis of rotation and said point .
- a radius of the first portion at the level of the impact zone is between 15 cm and 45 cm.
- the surface of revolution forming said shell comprises at least a first portion and a second portion forming a base to which said first portion is connected.
- the base is flat or tapered.
- the first portion is connected to said base by a connecting fillet ensuring a continuous slope variation between said base and said first portion; This ensures that the upper surface of the shell over which the liquid target material is spread in operation does not include any connection which could disturb the flow of the liquid.
- a radius of curvature of the fillet is between 5 mm and 50 mm.
- said first portion and said base are in one piece.
- said first portion and said base may be formed of two parts assembled by screwing or welding.
- the device for lifting the target material comprises one or more fins or a rotor, configured to be driven in rotation about an axis integral with the axis of rotation of shell.
- the spinning of the hull causes the liquid to circulate through the centrifugal effect as soon as the liquid has risen to the level of the upper surface of the hull without requiring another pumping mechanism for the liquid.
- said system for lifting the target material comprises a pump interposed between one end of the return duct and the reservoir.
- This device is more complex but can however make it possible to eliminate the correlation between the flow rate and the speed of rotation.
- the target further comprises a plate arranged above the shell, said plate making it possible in particular to limit the total surface of liquid in direct communication with the vacuum near the arrival zone of the beam.
- Said plate can be fixed, or rotating and integral with the shell.
- the target further comprises a fixed upper envelope arranged to envelop, at least partially, said upper surface of the shell.
- the target further comprises a fixed lower envelope arranged to envelop, at least partially, a lower surface of the shell opposite said upper surface.
- said lower envelope is integral with the reservoir. Said upper and / or lower envelopes make it possible to confine the vapors originating from the target material in the liquid state and to condense them on their walls.
- said upper envelope is traversed by said inlet duct allowing said beam of accelerated particles to be brought into said impact zone.
- said upper casing comprises one or more openings for pumping the target material in the liquid state and / or the passage of a device for driving the rotation of the shell if
- the gutter is integral with the upper casing, and is formed so as to encompass said outer periphery of the shell and to curl under the lower surface of the shell, opposite said upper surface.
- said upper and lower envelopes are connected, at least locally, by means of said gutter.
- the tank comprises an opening for the passage of a device for driving the rotation of the hull if
- the drive is done from the bottom, that is to say from the side of the lower surface of the hull, opposite to the upper surface. Said opening is then arranged to ensure a sealed passage of the drive device.
- the reservoir and / or the upper and / or lower envelopes are formed from a material comprising molybdenum, stainless steel or a combination of the two materials.
- the target comprises a plurality of return ducts between the gutter and the reservoir, for example between 2 and 8.
- Said return duct (s) can be of various shapes (circular section, ovoid , etc.) and with variable cross-sectional areas.
- the target is configured to accept a stable rotational speed of the hull with a speed between 300 and 800 revolutions / min.
- the total volume of target material in liquid state in a target is determined depending on the geometry of the system and the speed of nominal rotation selected for operation.
- the volume of liquid in the closed circulation system is between 2 and 5 liters, that is to say a volume nearly 3 times lower than the liquid volume required in targets based on liquid lithium known from the state of the art.
- the target is configured to produce, in operation, a web of target material in the liquid state having a thickness of between 50 ⁇ m and 5 mm.
- a thickness of between 80 ⁇ m and 140 ⁇ m, for example between 80 ⁇ m and 100 ⁇ m will be chosen in that it makes it possible to locate the maximum loss of energy, and therefore of heating. , in the surface area of the shell and not in the liquid lithium layer.
- too thin lithium thicknesses may lead to local dewetting of lithium on the surface of the hull.
- the inlet duct for the particle beam is arranged in a plane containing the axis of rotation of the shell. This configuration corresponds to a minimum deformation of the shape of the impact zone of the beam with respect to the section of the latter.
- the inlet duct for the particle beam is arranged in a plane tangential to a circumference of rotation at the level of the impact zone. This configuration corresponds to a significant deformation of the impact zone of the beam with respect to the section thereof.
- angles defining the orientation of the inlet duct with respect to the impact zone can be chosen to minimize the residence time of the target material at the end. liquid state under the accelerated particle beam.
- the inlet duct of the accelerated particle beam is equipped with a rapid beam shutter system.
- the inlet duct of the accelerated particle beam is equipped with a condenser.
- the target further comprises a device for preheating target material at the level of the reservoir.
- the target further comprises a device for preheating at least part of the upper casing and / or of the lower casing and / or of the reservoir.
- the target further comprises a cooling system.
- the target further comprises an enclosure configured to create at the impact zone a vacuum compatible with the generation of said nuclear particles.
- the present description relates to a system for producing nuclear particles comprising:
- a source of particles adapted to produce, upon interaction with a target material, said nuclear particles
- a particle accelerator configured to receive a beam of particles from said source and form a beam of accelerated particles; a target according to the first aspect comprising said target material and configured to receive, at the inlet duct, said beam of accelerated particles and generate at the impact zone said nuclear particles.
- the production system further comprises a neutron moderator arranged around the target.
- the source of particles emits protons or deuterons.
- the present description relates to a method for producing nuclear particles by means of a production system according to the second aspect.
- said method comprises:
- the method further comprises, in the case of solid target materials at ordinary temperature, a step of preheating the reservoir containing the target material and / or various elements of the target.
- the preheating step then allows the circulation of the liquid even in the absence of the thermal power transmitted by the accelerated particle beam, in the case of solid target material at room temperature.
- the method may alternatively comprise regulation of the cooling.
- the method further comprises cooling the target in the presence of the beam of accelerated particles, with a gradual stopping of the preheating, in correlation with the thermal power transmitted to the system by the latter.
- the speed of rotation of the shell is between 300 and 800 revolutions / min.
- the upward flow speed of the liquid on said upper surface of the shell is between 1 m / s and 3 m / s.
- the upward speed is defined as the speed of movement of the sheet of liquid relative to the hull.
- the tangential velocity of the liquid at the impact zone is between 5 m / s and 40 m / s.
- FIG. 1 schematically shows an example of a nuclear particle generation system according to the present description.
- FIG. 2 is a diagram illustrating the principle of a liquid target according to the present description.
- FIG. 3 A represents a diagram illustrating a first example of a shell in a target according to the present description.
- FIG. 3B represents a diagram illustrating a second example of a shell in a target according to the present description
- FIG. 4 represents a diagram illustrating an example of a liquid target according to the present description.
- FIG. 5 is a diagram showing the flow of liquid in the example target illustrated in FIG. 4.
- FIG. 6A represents a diagram describing the angular identification (b and c) of the arrival position of the particle beam with respect to the axis of rotation of the shell.
- FIG. 1 generally illustrates elements of a system 10 for producing nuclear particles in accordance with the present description.
- the system 10 comprises a source of particles 11, for example a source of protons or a source of deuterons, a particle accelerator 13 to form from the particles emitted by the source 11 a beam of accelerated particles and a target 15, the target 15 allowing, in operation, the interaction between the beam of accelerated particles and a sheet of target material in the liquid state to generate the nuclear particles.
- the target is also arranged within a vacuum chamber (not shown) compatible with the voids required for the particle beams.
- the target material can be metallic lithium, in the liquid state for temperatures above 180 ° C.
- the incident particles can be, according to one example, protons: a proton collides with a lithium nucleus ( 7 Li) to form by means of a nuclear reaction a beryllium nucleus ( 7 Be) with ejection of a neutron d energy between 25 keV and 785 keV.
- the incident particles are deuterons: a deuteron collides with a lithium nucleus ( 7 Li) to form, by means of a nuclear reaction, two 4 He nuclei.
- the system 10 can also comprise, all around the target 15, a moderating medium (not shown) to reduce the energy of the neutrons of the neutron field thus generated.
- the moderator comprises, for example, a hydrogenated medium (polyethylene or other).
- the moderator slows down the neutrons by allowing their backscattering towards target 15.
- these neutrons will interact with 7 Be, the product of the 7 Li (p, n) 7 Be reaction.
- the 7 Be transmutes into 7 Li according to the reaction 7 Be (n th , p) 7 Li.
- the product obtained is none other than the initial 7 Li which therefore corresponds self-regeneration of lithium. This allows do away with the need for a 7 Be trap and thus eliminate the risk
- FIG. 2 is a diagram illustrating the operating principle of a liquid target 20 according to an example of the present description.
- the target 20 shown schematically comprises a shell 24 formed by a surface of revolution and mounted in rotation about an axis of rotation 21 coincident with an axis of revolution of said shell.
- the shell comprises a frustoconical portion 242 whose apex is located on the axis of rotation and which has a given apex half-angle.
- the target 20 further comprises a reservoir (not shown in FIG. 2) comprising a target material in the liquid state in operation, for example lithium, and a device for lifting the target material (not shown in FIG. 2). ) configured to drive, in operation, the liquid state target material from the reservoir to the upper surface 244 of the rotating shell.
- An inlet duct (not shown in FIG. 2) makes it possible to bring, in operation, a beam of accelerated particles into an impact zone of the shell, the interaction of said accelerated particles with the target material in circulation on said upper surface of the shell generating nuclear particles by nuclear reaction. As illustrated in FIG.
- a liquid lithium thickness is sought at the level of the impact zone of less than 140 ⁇ m but sufficient not to fall within a range liable to generate dewetting of the film due to local fluctuations.
- this thickness is between 100 ⁇ m and 140 ⁇ m.
- a shell profile with a frustoconical portion allows an analytical calculation of the thickness of the liquid layer 22 as a function of parameters comprising: the apex half-angle a of the frustoconical portion, the speed of rotation co of the shell, the radius r of the frustoconical portion at the level of the impact zone and the flow of the liquid. These calculations can be based on the publications of S. V. Kralshevsky et al. (Ref. [5, 6]). In the particular case of recirculating targets based on a lifting system connected to the axis of rotation, the flow rate is not an independent parameter but is related to the speed of rotation of the hull.
- FIG. 3 A and 3B show two examples of portions of a shell 34 with profiles in a different meridian plane.
- the shell comprises a first portion 342 and a second portion 341 forming a base to which the first portion is connected.
- the sheet of liquid (not shown in FIGS. 3A, 3B) forms on an upper surface 344 of the shell and undergoes, in operation, an upward movement along the first portion 342. towards an outer periphery 345 of the shell.
- the surface 346 opposite the upper surface 344 is referred to as the lower surface of the shell.
- the first portion 342 is frustoconical.
- the base 341 and the frustoconical portion 342 are connected by a fillet 343 ensuring a smooth angular transition between these two portions to disturb as little as possible.
- the fillet 343 is characterized for example by a radius of curvature of between 5 mm and 50 mm.
- the shell is not necessarily composed of frustoconical elements and can be formed by a surface of revolution, the curvature of which changes regularly, as shown in FIG. 3B.
- the first portion 342 has a curved profile in a meridian plane containing the axis of revolution 31. In a target with a shell as shown in FIG.
- FIG. 4 represents a diagram illustrating a target 40 according to an example of the present description, for example, but not exclusively, a target based on liquid lithium.
- the target 40 comprises an axisymmetric shell 34 rotating about an axis of rotation 31 with a frustoconical portion 342 connected to a base 341, as in the example of FIG. 3 A.
- the shell further comprises in this example a third portion 440 forming a tubular extension immersed in a reservoir 46 comprising a target material in the liquid state in operation.
- the shell is formed from a material comprising, according to exemplary embodiments, molybdenum and / or a steel or a combination of the two materials.
- the target 40 further comprises an upper casing 452, fixed, arranged to at least partially envelop the upper surface 344 of the shell 34 on which, in operation, a sheet of target material in the liquid state is formed.
- the upper casing 452 aims to confine the vapors from the sheet of liquid formed, in operation, on the upper surface 344 of the hull.
- the target 40 further comprises a fixed lower envelope 451 which envelops the lower surface 346 of the shell 34 opposite the upper surface 344 on which the sheet of liquid is formed.
- a device for recovering the target material in the liquid state comprises a gutter 457 arranged on the outer periphery 345 of the shell and configured to receive, in operation, droplets originating from the sheet of target material induced by centrifugation, on the upper surface 344 of the shell.
- the projections of liquid induced by centrifugation of the liquid following the setting in rotation of the shell are received in the gutter 457.
- the lower casing 451 and the upper casing 452 are connected through the gutter.
- the gutter 457 is integral with the upper casing 452; more specifically, the gutter is formed in this example by folding one end of the upper casing 452 so as to encompass the outer rim 345 and to curl under the lower surface 344 of the hull.
- the target 40 further includes a reservoir 46 configured to contain, in operation, the target material in the liquid state
- the reservoir 46 is formed by a protuberance of the lower casing 451.
- the reservoir 46 is independent of the lower casing 451 and is made of a different material with a connection located at the bottom. level of a connection zone 462 between the reservoir and the lower casing. In normal operation, one will seek to ensure that the level of the liquid does not reach the connection zone 462 at the risk of being sucked by the centrifugal effect by the lower surface of the shell 346.
- the assembly comprising the lower casing 451, the upper casing 452 and the reservoir 46 in this example form a fixed casing 45.
- the casing 45 is made, for example, of stainless steel and / or a molybdenum-based alloy.
- a preheater (not shown in FIG. 4) may be provided at the reservoir 46 for preheating the target material before operation and interaction with the accelerated particle beam. Preheating can be useful in the case of a target material such as metallic lithium which occurs in a liquid state at temperatures above ambient temperatures.
- the target 40 also comprises an inlet duct 49 for a beam of accelerated particles 50.
- the inlet duct is arranged around the periphery of an opening 48 opening out through the upper casing 452; it defines by its orientation the impact zone on the rotating shell, as will be explained by means of FIGS 6A - 6C.
- the shape of the incident beam is defined upstream at the accelerator 13 (FIG. 1).
- the casing 45 and the inlet duct 49 are integral.
- a window (not shown in FIG. 4) can be used to separate the vacuum at the impact zone and the atmosphere of the target. Such a window is possible for example in cases where the energy of the beam allows it (sufficient transmission through the window).
- the transmission through a window would be insufficient and the inlet duct 49 of the particle beam can be equipped with a system of. rapid shut-off and / or a condenser (not shown in FIG. 4).
- the target 40 also comprises a device 47 for lifting the liquid from the reservoir 46 to the upper surface 344 of the shell 34.
- the lifting device 47 is inserted partially or totally in the tubular extension 440 of the shell 34 immersed in the reservoir.
- the extension 440 rotates at the same time as the hull and the lifting system.
- the extension 440 can be surrounded by a fixed tube, not shown in FIG. 4, making it possible to limit the propagation of the rotational movement of the tubular extension 440 of the shell 34 and of the lifting system, to all the liquid in the tank.
- the lifting device 47 is integral with the
- the lifting device comprises, for example, a fin system 471 or a suitable version of a centrifugal rotor. In this way, the rotation of the shell automatically causes the target material to rise to a liquid state.
- the gutter 457 is connected to the reservoir 46 by at least one return duct 43 forming a fluid connection between the two elements.
- the target material in the liquid state projected in the gutter is directly reinjected into the reservoir 46 by gravity without using additional energy for it.
- return conduits 43 make it possible to symmetrize the flows inside the reservoir.
- the return conduits 43 are for example 4 in number and are located at 90 ° to each other.
- the number of return conduits 43, their respective sizes and their positions can change without changing the subject of the present description. Support systems and stiffening of the assembly (shell, liquid return lines and envelopes) are not shown.
- the target 40 can comprise a plate 459 arranged above the hull.
- the plate 459 makes it possible in particular to limit the total liquid surface in direct communication with the vacuum near the arrival area of the beam. Said plate can be fixed, or rotating in this case integral with the shell.
- the target 40 may also include one or more preheating and / or cooling devices, for example at the level of the casings and return lines 43, depending on the target material used and / or one or more condensing devices, for example. for the condensation of lithium vapors.
- the lifting device 47 brings the target material in the liquid state, for example liquid lithium, to the center of the shell 34 so as to form a sheet of liquid as explained by means of FIG. 2.
- the rotation of the shell 34 at an angular speed w extends by centrifugal effect the sheet of liquid.
- the sheet of liquid then flows from the center to the outside of the portion
- the sheet thus formed extends over the entire upper surface 344 of the shell 34.
- the gyration causes the sheet to extend to the outer perimeter 345 of the shell 34 and to be projected into the gutter 457.
- the sheet liquid projected into the gutter is directly reinjected into the reservoir by gravity by means of return conduits 43 without using additional energy.
- the target 40 integrated into a generation system 10 as described for example by means of FIG. 1, makes it possible to implement a process for the production of nuclear particles, for example the generation of a neutron field in the case of using lithium as target material.
- the method comprises a preliminary step of obtaining a vacuum of sufficient quality around the target 40, by means of the vacuum chamber 42, then the setting in rotation of the shell 34 and of the control device. lifting 47 to form the sheet of liquid (22, FIG. 2).
- the admission of the beam of accelerated particles 50 coming from the particle accelerator 13 is then carried out in the inlet duct 49.
- the method may also include a preliminary step of preheating the reservoir 46 and / or parts of the casing. 45 and return lines 43.
- FIG. 5 is a diagram showing in more detail the circulation of the liquid in the example of target illustrated in FIG. 4 with the passage of the web 22 under the bundle area and the subsequent recovery of the fluid through the gutter 457.
- the web may remain whole after its detachment from the support shell or else stand break up into ligaments or droplets.
- FIGS. 6A to 6C illustrate more precisely the shape of the beam impact zone in different configurations of the inlet duct.
- the inlet duct of the particle beam is arranged such that the accelerated particle beam (indicated by a bold arrow in FIGS 6A to 6C) is incident in a direction of space indicated by the angles b and c.
- This configuration corresponds to a minimum of deformation of the impact zone of the beam compared to the section of the latter.
- This configuration corresponds to a significant deformation of the impact zone of the beam with respect to the section thereof.
- the target for the generation of nuclear particles comprises different variants, modifications and improvements which will be evident to those skilled in the art, it being understood that these different variants, modifications and improvements are within the scope of the invention as defined by the claims which follow.
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Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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FR1906353A FR3097401B1 (fr) | 2019-06-14 | 2019-06-14 | Cibles liquides pour la production de particules nucléaires |
PCT/EP2020/065875 WO2020249524A1 (fr) | 2019-06-14 | 2020-06-08 | Cibles liquides pour la production de particules nucléaires |
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EP3984336A1 true EP3984336A1 (fr) | 2022-04-20 |
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EP20734653.7A Pending EP3984336A1 (fr) | 2019-06-14 | 2020-06-08 | Cibles liquides pour la production de particules nucléaires |
Country Status (5)
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US (1) | US20220304135A1 (fr) |
EP (1) | EP3984336A1 (fr) |
JP (1) | JP2022543968A (fr) |
FR (1) | FR3097401B1 (fr) |
WO (1) | WO2020249524A1 (fr) |
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WO2023095818A1 (fr) * | 2021-11-24 | 2023-06-01 | 金属技研株式会社 | Procédé de production de radionucléides, dispositif de maintien de cible pour irradiation par faisceau quantique, système et cible |
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Publication number | Priority date | Publication date | Assignee | Title |
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US3733490A (en) * | 1971-01-08 | 1973-05-15 | En Atomique | Rotary target for electrostatic accelerator which operates as a neutron generator |
US3993910A (en) * | 1975-12-02 | 1976-11-23 | The United States Of America As Represented By The United States Energy Research & Development Administration | Liquid lithium target as a high intensity, high energy neutron source |
US5392319A (en) * | 1992-12-22 | 1995-02-21 | Eggers & Associates, Inc. | Accelerator-based neutron irradiation |
US5870447A (en) * | 1996-12-30 | 1999-02-09 | Brookhaven Science Associates | Method and apparatus for generating low energy nuclear particles |
CN104853515B (zh) * | 2015-06-12 | 2017-07-04 | 中国科学院近代物理研究所 | 上旋式液态无窗中子散裂靶件的自由液面形成构件 |
CN109257864B (zh) * | 2018-11-19 | 2024-07-02 | 中国科学院近代物理研究所 | 一种上旋式液态金属无窗散裂靶构件 |
-
2019
- 2019-06-14 FR FR1906353A patent/FR3097401B1/fr active Active
-
2020
- 2020-06-08 US US17/596,613 patent/US20220304135A1/en active Pending
- 2020-06-08 EP EP20734653.7A patent/EP3984336A1/fr active Pending
- 2020-06-08 WO PCT/EP2020/065875 patent/WO2020249524A1/fr active Application Filing
- 2020-06-08 JP JP2021574756A patent/JP2022543968A/ja active Pending
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FR3097401A1 (fr) | 2020-12-18 |
US20220304135A1 (en) | 2022-09-22 |
JP2022543968A (ja) | 2022-10-17 |
FR3097401B1 (fr) | 2021-10-01 |
WO2020249524A1 (fr) | 2020-12-17 |
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