Patent Application
20240212875
The present invention relates to a nuclear target, a method for inducing a nuclear reaction by means of the nuclear target and controlled nuclear reactions. In a preferred embodiment, the method for creating isotopes is performed using a laser-driven accelerator.
In another embodiments, the present invention relates to exothermic nuclear reactions and a method for converting nuclear energy into heat, a method for creating radioisotopes, in particular radiopharmaceuticals, and a method for treating burnt nuclear fuel, more specifically, a method for transmutation of nuclear fission products.
In another embodiment, the present invention relates to a device capable of carrying out the methods disclosed herein.
There are plurality of radioisotopes that are currently being utilized in medicine, energy or diagnostic methods using ionizing radiation. Some radioisotopes, in particular those used in medicine, often have a relatively short half-life. Therefore, there is a general need for a method for producing radioisotopes either at the particular place, where they are intended to be utilized, or at a place in relatively close distance. On the other hand, the products of fission reactions of 235U have a half-life of several decades. Therefore, there is a need for a method for transmuting radioactive material (waste) that is the final product of a fission nuclear reaction, preferably treating the waste at the place where they are going to be utilized, or at a place relatively close thereto.
There is also a continuing need to provide a clean energy source. One way to achieve such a clean energy source is to use exothermic nuclear reactions. According to the state of the art, there are two technical directions how to achieve energy production therefrom. One is nuclear fission, the other is nuclear fusion.
Laser is commonly used in industrial, scientific, and engineering applications.
However, it is still new to controlled nuclear reactions, as there is still a number of technical gaps that need to be addressed.
US 2016/0172065 discloses a nuclear target, system and method for creating isotopes thereof. The target contains a hollow, wherein a laser beam is focused into the hollow, creating plasma on the surface of the nuclear target. The target is then, but still during the plasma state, irradiated with a beam of projectile particles, such as protons. The target material and the type of particles are chosen according to the need of the nuclear reaction. Disclosed examples are, for example, 14N(p,α)11C; 11B(p,n)11C; 18O(p,n)18F; 20Ne(d,n)18F—as disclosed by the patent application; 16O(p,α)13N; 13C(p,n)13N; 14N(d,n)15O; 15N(p,n)15O.
According to US2016/0172065, the system comprises:
The use of the system according to US 2016/0172065 is exclusively disclosed for the creation of radioisotopes. The present solution is also very energy-demanding and lossless energy generation is impossible in the context of the present state of the art.
Another disclosed solution for generating high-energy particles for controlled nuclear 50 reactions using a high-intensity laser is US 2002/0172317. The apparatus contains two planar targets. The primary target, containing a thin Mylar film, is irradiated with a laser beam. Upon laser bombardment, the first target emits energetic particles, such as protons or deuterons, emitted towards the secondary target. The secondary target contains 10B, thereby inducing nuclear reactions due to proton or deuteron radiation emitted from the primary target.
An example of a disclosed nuclear target, apparatus and method for controlling fusion nuclear reactions is EP2833365. The target is planar and comprises two layers. The first layer comprises hydrogen-enriched silicon so that protons are emitted into the second layer upon the laser pulse irradiation. The second layer comprises boron, which in certain embodiments induces an exothermic nuclear reaction.
There are also capsule-shaped targets, as disclosed, for example, in US20120114088, wherein a compression of the envelope of the nuclear target occurs as a result of the mechanism of the laser radiation. Once atomic nuclei reach a certain distance, they fuse within a given target.
However, the above mentioned solutions provide low efficiency in the manufacturing of radioisotopes, since the target must always be supplied with a substantial part of energy, e.g. by means of laser radiation and/or external heating. In the case, in which the device is to lead to the fusion of nuclei, it is technically difficult to achieve the desired density of the generated plasma. Due to the growing application of radioisotopes in various fields of technology, there is a growing need for their generation using controlled nuclear reactions. The technical problem, which the present invention solves to a certain extent, lies in the method of more efficient generation of radioisotopes, or a more effective method for inducing a nuclear reaction.
The first embodiment of the present invention relates to a nuclear target suitable for increasing the efficiency to induce nuclear reactions, and thus also for the production of radioisotopes, in particular radiopharmaceuticals, or transmutation of burnt nuclear fuel and/or as means able to effectively induce exothermic nuclear reactions with significant thermal energy production.
The nuclear target according to the present invention, and as defined by claim 1, has the character of a bulk of material, comprising a hollow, wherein the shape of the hollow is preferably optimized with respect to the intention of the secondary nuclear reactions. The nuclear target is made of material comprising precursors. In a certain embodiment, the precursor may be implanted in the solid material of the target, while in another embodiment, the precursor may be placed in the hollow of the target in solid (e.g. powder), liquid, or gaseous form. In another embodiment, at least part of the nuclear target consists of the precursor. In another preferred embodiments, it is possible to combine the localization of the precursors as mentioned above, i.e. to provide powder precursor into the hollow of the nuclear target, while at least part of the nuclear target surrounding the hollow consists of the same or further precursor.
The precursor is formed by a specific predetermined isotope which, upon collision with a projectile particle, forms the desired product of a nuclear reaction, such as a radioisotope. The material of the nuclear target, more specifically the precursor, or a plurality of precursors, is selected for the nuclear reaction of the precursor(s) and the projectile particle(s) to achieve the final product(s), most often radioisotopes. The nuclear target further comprising at least one opening for the passage of a beam of projectile particles. The nuclear target is further equipped with a hollow in the bulk of the material located behind the opening, used for the incidence of projectile particles.
Projectile particles passing through the opening and incident on the hollow of the bulk of the material are either elastically scattered on at least one nucleus/nuclei of the isotope in the hollow, or the desired nuclear reaction with the isotope occurs 50 depending on the energy of the projectile particle. Some projectile particles may be reflected back—out of the hollow, wherein the reflected particles generate losses.
Losses can be minimized by the shape of the hollow, in particular, the geometry—by the position of the opening and the hollow. The elastic scattering of projectile particles on isotopes/nuclei in the hollow provides at least two technical effects. The first technical effect leads to the dissipation of energy inside the hollow, and thereby to the heating of the nuclear target material. The second technical effect relates to the transfer of kinetic energy to the target/isotope nuclei, which can thus exceed the threshold energy of the desired reactions.
The above-mentioned technical effects then provide a synergistic technical effect relating to the increased efficiency of radioisotope production or the yield of another desired nuclear reaction, for example the frequency of exothermic reactions or transmuted nuclei.
As mentioned above, the nuclear target is formed by a bulk of material, wherein the shape of the hollow is optimized with respect to the course of the desired nuclear reactions. In a certain embodiment, the bulk of the material can be a single bulk. In another embodiment, the single bulk can be divided into a plurality of segments. In another embodiment, the opening of the target facing the hollow may be slightly curved and/or contain a texture, in particular on the inner side of the hollow. However, the nuclear target must always contain at least one opening, preferably only one opening, for having projectile particles enter into the hollow of the nuclear target. Thus, the hollow of the nuclear target is never completely surrounded by the material containing the precursor(s) and isotopes on which the projectile particle is elastically scattered. The above preferred embodiment of only one opening provides the advantage of effectively trapping the scattered projectile particles, secondary particles and precursor particles accelerated by them. The probability of projectile particles escaping from the hollow, due to backscattering, can be minimized by a suitable geometry of the shape of the hollow.
The hollow can be of any shape. In a certain embodiment, the shape of the hollow may be part of an ellipsoid or a sphere. The optimized shape of the hollow, preferably of a more complex shape, can be generated by means of segments which form a single bulk upon their connection. In a preferred embodiment, the hollow comprises at least two parts. The first part consists of a narrower passage, while the second part consists of a wider and larger space. The first part can be in the shape of a cylinder, block or polyhedron, while the second part then follows seamlessly in the shape of a part of an ellipsoid, sphere or, for example, polyhedron. The geometry of the hollow, which is divided into at least two parts, offers the technical advantage of effectively trapping the projectile particles in the hollow, while considerably limiting the backscattering of the same. In a more preferred embodiment, the cross-sectional size of the first part of the hollow corresponds to the transverse size of the beam of projectile particles.
In the context of the present invention, a precursor refers to an atomic nucleus that interacts with a projectile particle, in particular there is a collision of a projectile particle with the atomic nucleus, with the interaction resulting in an induced nuclear reaction.
The end or intermediate product may be a radioisotope that further decay, for example, by an alpha, beta, and/or gamma decay, wherein the decay is further utilized in a particular industrial application. Intermediates may also be neutrons necessary for achieving the desired nuclear reactions. In a certain embodiment, the precursor may be implemented in the material, for example, by ion-atom implementation, or CVD, or PVD by atomic deposition onto a substrate. In another embodiment, the nuclear target can consist of precursor material surrounding the hollow, wherein at least one isotope, on which a projection particle is scattered, is presented in the material of the nuclear target. In another embodiment, the precursor may form part of the hollow so as to fill the precursor to a certain volume. In another embodiment, the 50 precursor may be included in both the material and the cavity filling. In this case, the precursor need not necessarily be one particular, but the first precursor may be implemented in the wall of the hollow or can form the hollow, while the second precursor may be part of the filling. The precursor may be, for example, 10B; 11B; natural mixture of boron; 13C; 14N; 15N; 16O; 18O; 20Ne; radiopharmaceuticals of 99Mo, 186W, fission reaction products, 233U, 235U, 239Pu. In a certain embodiment, the bulk of the material of the nuclear target can be manufactured from the respective precursor material.
Projectile particles are particles that bombard the nuclear target. Projectile particles can be, for example, protons, neutrons, deuterons, α-particles, light ions—for example 14C, 16O, medium-heavy ions (e.g. 27Al) or even heavy nuclei such as 197Au in case of use and depending on the material of the laser target. Projectile particles can be produced by state-of-the art accelerators or can be emitted by radioisotopes, e.g.
AmBe or PuBe or can be produced by laser driven accelerator.
The isotopes, on which elastic scattering with the projectile particles occur, may be the nuclei of the nuclear target, nuclei of the precursor and nuclei of the secondary products of the reactions already occurred if the energy of the projectile particles does not correspond to the resonant width of the allowed channels. If the precursor is not implemented in the material of the nuclear target, it is desirable that the possible reaction of the projectile and secondary particles with the nuclear target nuclei is the elastic scattering. These particles are thus partially reflected back and can interact with the nuclei of the precursor. For example, a tungsten nuclear target contains 180W,182W183W184W and 186W isotopes, wherein, in the case of protons as projectile particles with a proton energy of up to 6 MeV, practically only elastic scattering occurs.
The energy of the protons can dissipate through a multiple elastic scattering until it reaches resonant energy of some possible reaction with the precursor.
The induced nuclear reaction in the context of the present invention may be a nuclear transmutation, a spallation or fission nuclear reaction, a fusion reaction, or a compound nucleus reaction. Examples of suitable induced nuclear reactions are given below.
In a preferred embodiment, the nuclear target is further equipped with a laser target emitting projectile particles upon laser irradiation. The laser target can preferably be placed on the nuclear target opening. In another embodiment, the laser target may be positioned in front of the opening of the nuclear target to create space between the laser target emitting the projectile particles and the nuclear target opening. The space can be preferably used to filter out other particles formed by the laser irradiation of the laser target. In another embodiment, the opening between the laser target and the nuclear target may be closed and filled with a fluid, such as a fluid containing precursor nuclei. The embodiment disclosed above with the laser target further provides an advantage in the case of a nuclear target material comprising an electrically conductive material. A laser pulse emitted by, for example, a high-power pulsed laser may cause the generation of an electric current inside an electrically conductive nuclear target. In this case, the inset of the laser target is preferably in terms of a certain isolation of electromagnetic radiation affecting the electrically conductive nuclear target. In one embodiment, the parameters of the laser pulse can be taken from EP2833365.
In a certain embodiment, the material of the nuclear target may be suitably selected to consist only of a material containing exactly two isotopes. The first isotope is a precursor, and the second isotope is an isotope on which projectile particles are elastically scattered. The technical advantage of this embodiment is that only two interactions occur in the hollow of the nuclear target immediately after irradiation. The first interaction induces a nuclear reaction of the precursor with the projectile particle.
The second interaction represents elastic scattering of the projectile on the isotope. Thus, the efficiency of induction of the nuclear reaction or production of radioisotopes is enhanced. After some time, however, due to the nuclear interaction with the 50 precursor, the products hereof appear, also entering into the ongoing interactions.
In another embodiment, the laser target material can be preferably selected to comprise multiple isotopes. If a laser target consists of multiple isotopes, their emitted ions forming projectile particles will interact with the nuclear target in a certain sequence. This can be used to influence the kinetics of the ongoing reactions. The 55 above sequence of incident projectile particles providing a sequence of induced nuclear reactions in the hollow of the nuclear target can be ensured by making a nuclear target provided with an inset laser target. The size of the inset can be advantageously selected according to reaction kinetics.
In accordance with the IAEA convention, hereinafter, we will use the so-called abbreviated notation of nuclear reactions, i.e. the reaction projectile P+target T→emitted particle X+residual nucleus Ras T (P, X) R. The isotopes 1H, 2H, 3H and 4He are accordingly labelled, when they act in the reaction as a target, i.e. a precursor, or a residual nucleus. 2H and 3H are sometimes labelled in accordance with the convention as D and T, respectively. If the isotopes 1H, 2H, 3H and 4He appear as projectile or emitted particles, we will denote them in accordance with the convention of p, d, t and a, respectively. Other isotopes are labelled by default in all roles in the reaction.
In another preferred embodiment, the inner wall of the hollow is provided with a layer comprising material emitting secondary projectile particles, which are emitted from this layer upon the interaction of the primary projectile particle or another particle with sufficient momentum. In another embodiment, the hollow can be provided, in its volume, with a material capable of emitting secondary projectile particles upon an interaction of the projectile and/or another particle. The above approaches may also be combined. Examples of such materials are: 1H, 2H which, for practical reasons, may be present in the form of compounds, e.g. polyethylene or HDPE (high density polyethylene). The inner wall of the hollow does not have to be entirely covered with this layer; only a covered part is sufficient. The advantage of this embodiment is the chain growth of the projectile particles in the hollow. The primary projectile particles and the secondary projectile particles need not be the same. For example, the primary projectile particle may be a proton and the secondary projectile particle may be, for instance, an alpha particle or a neutron.
In another preferred embodiment, the nuclear target can be provided with a plurality of openings following on the corresponding plurality of hollows. This preferred embodiment represents an advantage in the continuous operation of induced exothermic nuclear reactions and/or the production of radioisotopes. The nuclear target can be placed on a motorized holder which moves with the nuclear target in any direction and/or rotates it. As soon as a sufficient amount of radioisotopes is produced according to the corresponding induced nuclear reaction, or the entire precursor in the hollow of the nuclear target is consumed, the nuclear target is moved so that the incident projectile particles fall into the next hollow or hollows containing still unconsumed precursor.
In another preferred embodiment, the material of the nuclear target or the precursors may be selected according to the respective industrial application. In a certain embodiment being advantageous for radioisotope production, the following precursors 11B, 98Mo, 186W, or a mixture of precursors 98Mo and 2H, may be selected.
In another embodiment being advantageous for the production of isotopes suitable for diagnostic methods using ionizing radiation, precursors may be selected from the following group of 185Re, 187Re or a natural mixture of NatRe. In another embodiment being advantageous for industrial applications of spent nuclear waste transmutation, a nuclear target precursor is selected, or the material of the nuclear target is made up of isotopes with a longer half-life. Such isotopes include the fission products of 233U, 235U, 239Pu. In this case, it is also suitable to use as an additional precursor a material also providing neutrons after being irradiated with projectile particles, e.g. 2H upon irradiation with protons or 3H upon irradiation with deuterons. In another embodiment, preferred for the conversion of nuclear energy into heat, 2H, 6Li, 7Li, 10B, 11B, 15N or a mixture thereof is selected as the precursor.
In another preferred embodiment, a luminophore or scintillator can be applied to the opening and/or into a part of the hollow. The luminophore, or scintillator, brings a dual technical function. The first function consists in controlling the emission of radioactive 55 particles from the hollow of the nuclear target. Emissions of radioactive particles need not necessarily be subatomic or atomic particles but may also form a macroscopic part of the hollow which, due to the reaction mechanism, has ejected part of the material out of the hollow. The second technical function consists in controlling the focusing of the beam of projectile particles and the deposition thereof into the hollow of the nuclear target, or in controlling the optimal shape of the same.
A second embodiment of the present invention relates to a method for inducing a nuclear reaction as defined by claim 12. The method according to the present invention is fully universal and can be applied to a number of industrial issues, which are mentioned above.
The method includes a step of providing a beam of projectile particles incident on a nuclear target from a precursor-containing material bulk. The nature of the invention for carrying out this method is characterized in that the beam of projectile particles is focused into the hollow of the nuclear target, with the projectile particles being elastically scattered on the nuclei of at least one isotope inside the hollow; the elastic scattering preferably occurs on the isotopes contained in the hollow fill and/or on the isotopes of the wall of the nuclear target. The projectile particles are elastically scattered until they induce a nuclear reaction on the precursor, or until the occurrence of an interaction between the projectile particle and the precursor.
In a preferred embodiment, the projectile particles are generated in a laser-controlled accelerator. A laser-controlled accelerator is generally considered to be a more compact and cheaper option compared to commonly used accelerators.
In another preferred embodiment, radiopharmaceuticals can be produced by the method of the invention, wherein the projectile particles and precursors are selected according to the following nuclear reactions 11B(p,n)11C, 98Mo(p,n)99mTc, 186W(p,n)186Re or a mixture of precursors 98Mo and 2H to induce simultaneous reactions of 2H(d,n+p)2H and/or 2H(d,n)3He with a subsequent reaction of 98Mo(p,n)99mTc and 98Mo(n,Y)99mTc, when using projectiles d. Reactions of 185Re(n,γ)186Re, 187Re(n,γ)188Re are also possible, again in a preferred embodiment using deuterium as a projectile particle, more preferably deuterium generated from a laser target and/or deuterium present in the hollow of the nuclear target and activated by an elastic collision with any projectile particle.
In another preferred embodiment, the nuclei of the spent nuclear waste can be transmuted by the method, wherein the projectile particles and precursors are selected according to the following nuclear reactions 233U(p,fission), 235U(p,fission), 239Pu(p,fission), and, in particular, 233U(n,fission), 235U(n,fission), 239Pu(n,fission), or 60Co(n,γ)61Co. During fission induced by neutrons, neutrons must be produced by the interaction of neutrons as projectile particles with the precursor. In a certain embodiment, neutron production can be achieved, for example, by an additional projectile particle and a precursor containing deuterons. In the interaction of the particles of this embodiment, reactions of 2H(d,n)3He and/or 2H(d,n+p)2H, or 2H(d,p)3H and subsequently of 2H(t,n)4He occur, or the precursor will contain tritium 3H, wherein a reaction of 3H(d,n)4He occurs.
In another preferred embodiment, nuclear energy can be converted into heat by the method, wherein the projectile particles and precursors are selected according to the following nuclear reactions 3He(d,p)4He, 6Li(d,α)4He, 7Li(p,α)4He, 10B(p,α)7Be, 11B(p,2α)4He, 15N(p,α)12C or 6Li(p, 3He)4He followed by secondary reactions 6Li(3He,2α)1H a 3He(3He,2p)4He. Other possible reactions include 3H(d,n)4He, 2H(t,n)4He, 2H(n,γ)3H, 6Li(n3He)4He, 10B(n,α)7Li, 7Be(n,p)7Li, 13C(n,γ)14c, 14N(n,p)14c, 17O(n,O)14O 21Ne(n,α)18O, 22Na(n,p)22Ne or 37Ar(n,α)34S. In a more preferred 50 embodiment, heat is conducted from the nuclear target using a heat exchanger.
A third embodiment of the present invention relates to a device suitable, i.e. not exclusively used, for carrying out the method according to the second embodiment of the present invention, or preferred embodiments. The device is defined in claim 19.
The device comprises a projectile particle source and a nuclear target according to 55 the present invention, wherein the projectile particle source is configured to deposit projectile particles into the hollow of the nuclear target according to the present invention.
In a preferred embodiment, the device comprises a nuclear and a laser target, wherein the nuclear target is a nuclear target according to the present invention and the laser target is capable of emitting projectile particles upon laser pulse strike. The laser target can be solid-state, such as the laser target disclosed in EP2833365, or a gas jet target can also be used, using the laser-wakefield acceleration phenomenon.
In other preferred embodiments, the device is configured to carry out the methods according to the present invention.
Radioisotopes are produced by bombarding or irradiating a nuclear target 1 comprising precursor(s) 21 or 22 and/or 23. Precursor 21 and/or 22 and/or 23 refers to, and is generally known in the art, an atomic nucleus that interacts with a projectile particle 3 to achieve the final product. The final product is often an unstable radioisotope that further decays by alpha, beta and/or gamma decay. The generation of products by induced nuclear reactions according to the present invention takes 50 place substantially inside the hollow 12 of the nuclear target 1, wherein at least a portion of the precursors 21 and/or 22 and/or 23 present/comprised in the hollow 12 interact with projectile particles 3 and form the final product by nuclear reactions. In most cases, the product formed, most often a radioisotope, is consequently mixed with another material forming the nuclear target 1, wherein the untransformed precursor 21 and/or 22 and/or 23 remains randomly distributed in said nuclear target 1. Certain portion of the converted precursors 21 and/or 22 and/or 23 to the final product(s) can be separated using chemical methods. An example of a chemical method for separating converted radioisotopes consists in dissolving the nuclear target 1, or the content of the hollow 12 of the target 1, in a strong acid, followed by filtration of radioisotopes and precipitation thereof.
The nuclear target 1 according to the present invention comprises at least one nucleus of the precursor 21 or 22 in the envelope of the nuclear target 1 and/or the precursor 23 inside the hollow 12, which is transformed into the product nucleus by the nuclear reaction; and an isotope 4 on which the projectile particle 3 is elastically scattered until the interaction with the nucleus of the precursor 21 and/or 22 and/or 23. In the case of the example according to
According to another example of an embodiment, the nuclear target 1 may contain a natural mixture of boron, i.e. 20% of 10B and 80% of 11B, as the nuclei of the precursor 21 and/or 22 and/or 23.
In another embodiment, the nuclear target 1 can be enriched, for example a target having 10B with up to 90% in concentration, thereby inducing an appropriate reaction scheme according to the nuclear reaction mentioned above. It is also possible to select the distribution of precursors 21 and/or 22 and/or 23, e.g. a higher concentration of precursors 21 and/or 22 and/or 23 at the edges of the nuclear target 1 in accordance with its intended use. It is also possible to use two types of precursors 21 and/or 22 and/or 23, or a simultaneous placement, for example, the arrangement according to
The nuclear target 1 may be substantially of a planar shape, being provided with an opening 11 and a hollow 12 in a bulk of material located behind the opening 11. The hollow 12 can take any shape.
In the preferred embodiment schematically illustrated in
Another advantage of the hollow 12 having parts 121 and 122 is characterized in that it is not necessary for the beam 3 of projectile particles 3 to be focused perpendicularly to the nuclear target 1. The beam of projectile particles 3 can be deposited into the hollow 12, e.g. according to
The opening 11 of the nuclear target 1 serves for the entry of projectile particles 3, such as protons, deuterons, light nuclei, which can be accelerated in commonly used particle accelerators. In another embodiment, laser-controlled accelerators may be used. In another embodiment, a collimated beam of projectile particles 3 from static emitters, such as AmBe, RaBe or PuBe, can also be used. In the case of neutrons used as projectile particles 3, it is also possible to use spallation sources or a collimated beam of neutron coming from a fission reactor. The projectile particles 3 pass through the opening 11 of the nuclear target 1 and are deposited in the cavity 12 thereof. Ideally, there are exactly two possible interactions occurring in the hollow 12. The first interaction consists of the induced nuclear reaction of the projectile particle 3 with the precursor 21 and/or 22 and/or 23, wherein the projectile particle 3 and the precursor 21 and/or 22 and/or 23 are suitably selected according to the industrial application. In the latter case of the desired interaction, the projectile 50 particles 3 are elastically scattered on the isotopes 4, wherein the kinetic energy of the projectile particles 3 is dissipated until the projectile particle 3 interacts with the desired nuclear reaction selected from possible interaction channels and a nuclear reaction occurs on the precursor 21 and/or 22 and/or 23.
The volume of the nuclear target 1, the thicknesses of the walls of the nuclear target 1, the size and shape of the hollow 12, the distribution of the precursors 21 and/or 22 and/or 23, and other commonly needed parameters of the nuclear target 1 are appropriately selected according to the desired nuclear reaction and relevant industrial application. Commonly used computer programs can be used to determine the above parameters.
The final product of the reaction of the projectile particles 3 with the nuclei of the precursor 21 and/or 22 and/or 23 may be, for example, radioisotopes used in radiation therapy, radioisotopes used for imaging in medical applications and/or diagnostics of materials. In another embodiment, the final product may be a stable isotope 4 having a short and/or medium half-life. In another embodiment, the final product may be a stable isotope 4 made in exothermic nuclear reaction, which can then be converted to heat 9 in a heat convertor 91.
In the embodiments according to
Preferred embodiments provided with a laser target 5 are capable of providing a high-energy beam of hadron particles, such as protons, light nuclei, heavy nuclei (e.g. Au) 50 or neutrons, but also an electron beam without the need for complex beam-transport. The preferred embodiment illustrated in
In another preferred embodiment, the material of the laser target 5, structure and thickness thereof can be selected so that a suitably selected focus of the laser pulse (pulse cross-section) using the TNSA mechanism leads to the production of optimal spectrum of projectile particles, both in intensity and the energy spectrum of the particles. In a certain example of the embodiment, the isotopic composition of the nuclear target 1 is selected to consist of exactly two isotopes. The first isotope is a precursor 21 and/or 22 and/or 23, which is localized in the envelope and/or hollow 12 of the nuclear target 1. The second isotope is a nucleus on which the projectile particles 3 are elastically scattered. This embodiment provides an advantage in that immediately after the bombardment of the projectile particles 3, only the interaction with precursor 21 and/or 22 and/or 23 is allowed, or the projectile particles 3 are elastically scattered on the isotopes 4 until they interact with the nucleus of the precursor 21 and/or 22 and/or 23. In the next phase, products of ongoing nuclear reactions with projectile particles 3 may also enter the process. These may by, for instance, ions with a smaller mass-to-charge ratio, which reach the hollow 12 with a certain delay, as reported by Torrisi, Lorenzo & Cavallaro, Stefano & Cutroneo, M. & Krasa, Josef & Klir, Daniel. (2014). D-D nuclear fusion induced by laser-generated plasma at 1016 W cm-2 intensity. Physica Scripta. 2014. 014026. 10.1088/0031-8949/2014/T161/014026. Ultimately, the yield of the nuclear reaction increases.
In the example illustrated in
More specifically, for example, the technical function of the layer 32 according to the embodiment illustrated on
This example can be used, for example, in the case of exothermic nuclear reactions with a heat exchanger 91 located around the nuclear target 1. Another advantage of this embodiment is characterized in that the nuclear target 1 can form an endless band which is irradiated by one source of projectile particles 3, wherein the nuclear target 1 moves in the direction 7 as necessary.
The above-mentioned embodiments can be combined with the preferred nuclear reactions selected in accordance with the use of the present invention. In one embodiment, a nuclear target 1 further provided with a laser target 5 can be used, for example consisting of a layer 50 of polymer (CD2)n-polyethylene, where hydrogen nuclei are replaced by deuterium nuclei, e.g. according to Torris, L. and Cutroneo, M., “Triple nuclear reactions (d, n) in laser-generated plasma from deuterated targets”, Physics of Plasmas, vol. 24, no. 6. 2017. doi: 10.1063/1.4984997. The nuclear target 1 can be made of tungsten and is filled with precursors 21 or 22 and 23 of 6LiD and/or 7LiD or NatLiD. A beam of accelerated deuterons, carbon nuclei and proton admixture, which forms a beam of projectile particles 3 that is emitted from the laser target 5 towards the hollow 12 of the nuclear target 1. The projectile particles 3 collide with the 55 nuclei of the precursor 21 and/or 22 and/or 23 contained in the hollow 12 of the nuclear target 1. This induces the respective nuclear reactions inside the hollow 12 of the nuclear target 1, which in the case of the D-D and Li-D (7Li(d,n)8Be) reactions produce neutrons. The projectile particles 3, which do not collide with the nuclei of the precursor 21 and/or 22 and/or 23, are elastically scattered on the isotopes 4, or on the nuclei of the products of the occurred reactions of the projectile particles 3 with the precursor 21 and/or 22 and/or 23 until the respective nuclear reaction occurs on precursor 21 and/or 22 and/or 23.
In another example, the laser target 5 may consist of a layer 50 of HDPE. According to this example, accelerated projectile particles 3, protons, are generated from the laser target 5, leading to an induced nuclear reaction with the precursor 21 and/or 22 and/or 23 in the form of, for instance, powdered amorphous 10B and/or 11B or NatB. In this example, the following reactions are possible: 11B(p,n)11C with the ongoing parallel reactions of 11B(p,α)8Be and 10B(p,α)7Be. The resulting radioisotopes can then be chemically separated, with one of the resulting products, namely 11C, being a pure positron emitter with a half-life of 20 minutes and can be used for medical diagnostics or diagnostics of defects in materials. In another embodiment, the laser target 5 can be a layer 50 of a polymer film (CD2)n capable of emitting deuterons, wherein 185Re, 187Re, or a natural mixture of NatRe may be used as the precursor 21 and/or 22 and/or 23 in the nuclear target 1. Natural rhenium consists of two isotopes, 185Re and 187Re in a ratio of 37.4: 62.6. According to this example, projectile particles 3, deuterons, are generated from the laser target 5, and if deuterons are contained in the precursor 21 and/or 22 and/or 23 in the hollow 12 of the nuclear target 1, the nuclear reactions of 2H(d,n)3He or 2H(d,n+p)2H lead to the production of neutrons and, subsequently, the reactions of 185Re(n, y)186Re, 187Re(n,y)188Re lead to the production of 186Re and 188Re radionuclides with half-lives of 90 and 17 hours, used in medicine like 99mTc. In another example, it is possible to use the reactions 3He(d,p)4He, 6Li(d,α)4He, 7Li(p,α)4He, 10B(p,α)7Be, 11B(p,2α)4He, 15N(p,α)12C or 6Li(p,3He)4He followed by secondary reactions 3He(6Li,2α)1H and 3He(3He,2p)4He for the purpose of inducing an exothermic nuclear reaction. Other possible exothermic nuclear reactions include 3H(d,n)4He, 2H(n,γ)3H, 6Li(n3He)4He, 10B(n,α)7Li, 7Be(n,p)7Li, 13C(n,γ)14c, 14N(n,p)14c, 17O(n,O)14O 21Ne(n,α)18O, 22Na(n,p)22Ne or 37Ar(n,α)34S. The released energy can be converted into heat 9.
In the following examples of the embodiments, the invention discloses methods for inducing nuclear reactions. In a first step, a beam of projectile particles 3 is provided.
The projectile particles 3, in a preferred embodiment, have a spectrum and intensity optimized with respect to the desired reactions. These projectile particles 3 are deposited in the hollow 12 of the nuclear target 1 containing the nuclei of the precursors 21 and/or 22 and/or 23. The projectile particles 3 either induce a nuclear 50 reaction or are elastically scattered on the isotope 4 of the material from which the nuclear target 1 is made. In a certain step of the method of the invention, after the induced reaction is burned up, the radioisotope production method ends or may be repeated; the repetition may occur in the same hollow 12 of the nuclear target 1, or the nuclear target 1 may be further moved and the projectile particles 3 are focused into a new hollow 12 containing previously unconsumed precursors 21 and/or 22 and/or 23.
One way to detect the number of nuclear reactions that have occurred on the precursor 21 and/or 22 and/or 23 is to measure the ionizing radiation emanating from the nuclear target 1. In one embodiment, nuclear reactions 10B(p,α)7Be can be used, thereby detecting gamma radiation from de-excitation of 7Be. Monitoring of gamma radiation can then serve as an indicator of the number of induced nuclear reactions.
The accelerated projectile particles 3 can also be positive ions that can induce nuclear fusion or nuclear fission with other materials inside the hollow 12 of the nuclear target 1.
In a certain example, by combining the materials of the irradiated nuclear target 1, preferably by generating accelerated projectile particles 3 by means of the laser target 5, it is possible to induce many reactions other than those mentioned above.
Another combinations include collisions of protons, as high energy projectile particles 3 with high energy, with the nuclei of 16O of the precursor 21 and/or 22 and/or 23. The collision may induce a nuclear reaction of 16O(p,α)13N, wherein 13N is a short half-life radioisotope that may further decay by alpha decay.
In another embodiment, protons, as accelerated projectile particles 3, collide with a nuclear target 1 containing nuclei 18O of the precursor 21 and/or 22 and/or 23, thereby inducing a nuclear fusion 18O(p, n)18F, wherein 18F is a radioisotope with a half-life of 109 minutes.
In another example, protons, as accelerated projectile particles 3, collide with a nuclear target 1 containing 10B, which induces a nuclear reaction of 10B(p,α)7Be, wherein 7Be is a radioisotope with a half-life of 53 days.
In another example, protons, as accelerated projectile particles 3, collide with a nuclear target 1 containing 15N, which induces a nuclear reaction of 15N(p,n)15O, wherein 15O is a radioisotope with a short half-life.
By using other projectile particles 3, or using another laser target 5, it is possible to generate positive ion projectile particles 3. In a certain embodiment, it may be a high-energy deuteron falling into the hollow 12 of the nuclear target 1 containing the nuclei of 12C of the precursor 21 and/or 22 and/or 23 which may induce a nuclear reaction of 12C(d,n)13N, wherein 13N is a radioisotope with a short half-life.
In another example, the collision of deuterons, as accelerated projectile particles 3, with the nucleus of 14N of the precursor 21 and/or 22 and/or 23 may induce a nuclear reaction of 14N(d,n)15O, wherein 150 is a radioisotope with a short half-life.
In another example, the collision of deuterons, as accelerated projectile particles 3, with the nucleus of 20Ne of the precursor 21 and/or 22 and/or 23 may induce a nuclear reaction of 20Ne(d,α)18F, wherein 18F is a radioisotope with a short half-life.
In other examples, a neutron can be used as the projectile particle 3, wherein it can either be accelerated by a two-stage laser target 5, where protons generated in the first laser target fall on the second laser target made of, for instance, LiF. Further, as part of the deuteron, stripping reactions are used in the reactions with the precursor 21 and/or 22 and/or 23, neutrons can be produced directly in the hollow 12, for example by means of 2H(d,n)3He, 2H(d,n+p)2H reactions and, in particular, 3H(d,n)4He.
In another embodiment, neutrons can also be used as projectile particles 3 for nuclear fission according to the scheme by means of the 2H(d,n)3He, 2H(d,n+p)2H reactions and, in particular, 3H(d,n)4He.
In another example, the nuclear target 1 can be enriched with nuclei of burnt nuclear 50 fuel or made from the material of burnt nuclear fuel, wherein a tritium precursor 23 bombarded with projectile particles 3—deuterons—is placed in the hollow 12, forming a neutron pulse that fissions nuclei of heavy nuclei in 233U(n,fission), 235U(n,fission), 239Pu(n,fission) reactions.
In another example of the embodiment—schematically illustrated according to
An experimental setup was dedicated to behaviour of the nuclear target according to the present invention. A schematic drawings corresponding to the experimental proof are shown in
The experimental setup, as shown in
In the experiment, the laser shots were directed to the hollows covered by MYLAR foil. According to the inventor's observation, the laser shots do not produce any effect of the tungsten surface of the nuclear target, irrespective of the energy of the laser pulse. It was especially evident on target #2, where laser shot missed the hollow and hit tungsten surface. The coumarin fill was not ejected from the hollow by laser shot, therefore it can be efficiently used for monitoring of nuclear reaction therein.
The powdery target material with low atomic number Z allows sufficiently long mean free path for re-scattering of both projectile and secondary particles, which leads to dissipation of beam energy within certain volume of the target. Contrary to this, high Z tungsten body of the target with large Coulomb barrier reflects the beam particles without any apparent changes of the target body at given beam parameters. The inventor further provides post-experimental analysis for each hollow, which was intended for a shot. The representative examples are shown in
The present invention finds application in several industries, as, to some extent, it represents a universal method for inducing nuclear reactions. In a certain industrial application, the present invention can be used for producing radioisotopes, particularly radiopharmaceuticals. In another industrial application, the present invention can be used for transmutation of burnt nuclear fuel so that hazardous nuclear waste is converted to stable isotopes, or at least isotopes with a short half-life. In a third, but not last, industrial application, the present invention can be used to produce heat from a controlled nuclear reaction.
| Number | Date | Country | Kind |
|---|---|---|---|
| PV 2021-189 | Apr 2021 | CZ | national |
| LU 102817 | Jun 2021 | LU | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CZ2022/050041 | 4/19/2022 | WO |
