Methods used for ion collection

Abstract

The present application provides a method for ion collection, the method comprising accelerating ions toward a carbon fiber lattice and trapping the ions in the carbon fiber lattice.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 251,397, filed on October 1, 2021, which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates generally to the field of heavy metal ion generation, such as for healthcare applications. More specifically, the present disclosure relates to improving the efficiency of collecting and constituting ions accelerated from an ion source at high extraction energies. Background Art

[0004] Prior art involving ion beams is generally intended to provide high energy collisions between the ion beam and a substrate material in order to cause changes in the substrate material. The ions in such systems themselves cannot be effectively retained in the substrate material, and they may be sputtered, sublimated, or scattered away. Such systems and methods do not provide efficient collection of the ions themselves. In contrast, one object of the present application is to collect ions of an ion beam as a constituent material that can be collected, stored, transported, used, etc., for example in healthcare applications. Summary of the invention

[0005] One embodiment of the present disclosure is a method. The method includes providing a carbon fiber lattice, accelerating ions toward the carbon fiber lattice, and trapping the ions in the carbon fiber lattice. The method may also include burning the carbon fiber lattice to obtain a residue including the ions.

[0006] The ions may be ytterbium ions. In some embodiments, the ions include ytterbium-176 ions, and the method further includes separating the ytterbium-176 ions from other isotopes prior to trapping the ions in the carbon fiber lattice.

[0007] In some embodiments, accelerating the ions toward the carbon fiber lattice includes providing the ions with energy greater than 100 V. Trapping the ions in the carbon fiber lattice may include decelerating the ions by deflecting the ions away from a plurality of carbon fibers of the carbon fiber lattice.

[0008] In some embodiments, the method includes increasing the area of ​​the carbon fiber lattice that traps ions by operating an actuator to rotate or translate the carbon fiber lattice. The method may also include providing multiple layers of fibrous carbon material. Providing the carbon fiber lattice may include arranging the carbon fibers in multiple directions.

[0009] Another embodiment of the present disclosure is an ion generation system. The ion generation system may include: an ion source configured to generate ions; a target, the target including a fiber lattice; and an electrode located between the ion source and the target substrate and configured to accelerate the ions toward the target substrate so that the ions are incident on the fiber lattice. The fiber lattice is configured to capture ions. The ions may be ytterbium ions, for example, including ytterbium-176 ions.

[0010] The fiber lattice may include a plurality of carbon fibers arranged in a plurality of directions. The target may include a plurality of layers of the fiber lattice. The fiber lattice may include graphite or carbon and may be configured to burn. After the fiber lattice burns, the fiber lattice may leave a residue including ions.

[0011] In some embodiments, the electrodes provide ions with an energy greater than 100 V. In some embodiments, the target includes a mount configured to releasably secure the fiber lattice in position relative to the mount. The ion generation system may include an actuator operable to rotate the target. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The present disclosure will be more fully understood through the following detailed description taken in conjunction with the accompanying drawings, in which like reference numerals refer to like elements, and in which:

[0013] Figure 1 is a schematic diagram of an ion generating system according to an illustrative embodiment.

[0014] Figure 2 is a schematic diagram of a target and voltage source for an ion generation system in an embodiment involving positive ions according to an illustrative embodiment.

[0015] Figure 3 is a schematic diagram of a target and voltage source for an ion generation system in an embodiment involving negative ions according to an illustrative embodiment.

[0016] Figure 4 is a block diagram of an ion generation system with a magnetic rotation device according to some embodiments.

[0017] Figure 5 is an exploded view of a fiber lattice of a target of an ion generation system according to some embodiments.

[0018] Figure 6 is a perspective view of a fiber lattice of a target of an ion generation system according to some embodiments.

[0019] Figure 7 is a top view of a target of an ion generation system according to some embodiments.

[0020] Figure 8is a top view of a fiber lattice of a target of an ion generation system according to some experimental results.

[0021] Fig. 9 is a top view of a fiber lattice of a target of an ion generation system according to some experimental results. DETAILED DESCRIPTION

[0022] Before turning to the drawings showing certain embodiments in detail, it should be understood that the present disclosure is not limited to the details or methods set forth in the specification or shown in the drawings. In addition, it should be understood that the terminology used herein is for descriptive purposes only and should not be regarded as limiting.

[0023] Referring generally to the accompanying drawings, systems and methods involving ion generation systems (e.g., heavy metal ion generation systems) according to various exemplary embodiments are shown. Specifically, the accompanying drawings generally illustrate systems and methods involving efficient collection of ions (e.g., heavy metal ions, such as ytterbium ions, including ytterbium-176 ions) at a target in an ion generation system such that the ions are reconstructed into a material (e.g., a material having a high concentration of ytterbium-176 or other desired isotopes), which can then be collected, stored, transported, used, etc. for various applications.

[0024] As described in detail below, ions are generated in an ion source and extracted from the ion source as an ion beam with a high extraction energy, for example, between 20 kV and 80 kV (for example, between 40 kV and 60 kV) (note that in this case, the ion kinetic energy is usually expressed in volts, one volt equals one joule / coulomb; in other conventions, these values ​​can be expressed in keV). The ion beam can pass through a magnetic analyzer and a mass-resolving aperture, which uses a magnetic field to sort the ions by momentum (or, if all generated ions have the same charge, sort by atomic mass), and the mass-resolving aperture is arranged relative to the ion beam and the magnetic analyzer to mainly allow the desired ions (for example, ions of the desired isotope) to pass, while preventing other ions from passing through the aperture. An ion beam having only the desired ions or a high percentage of the desired ions therefore passes through the aperture. Therefore, the mass-resolving aperture separates the desired ions or a high percentage of the desired ions. The target (target substrate, substrate, etc.) is positioned so that the desired ion beam is incident on the target.

[0025] The methods described herein provide a high rate of ion adhesion to the target and a low sputtering rate on the target, thereby increasing the percentage of ions that constitute neutral materials (e.g., of the desired isotope) and reducing the percentage of lost ions. The overall efficiency of the entire ion generation system (e.g., power and resource consumption per unit of produced material) is therefore improved. The accumulation of ions on other undesirable surfaces of the ion generation system (which may otherwise be caused by ion scattering) can also be minimized or prevented, thereby reducing downtime and maintenance of the ion generation system. In addition, the methods herein can reduce heat transfer to the target substrate (heat load on the target, thermal energy load on the target), thereby reducing or eliminating temperature management problems that may otherwise be caused by high-energy collisions at the target.

[0026] As described in detail below, by keeping the target at a voltage with the same polarity as the ion and slightly lower amplitude than the potential of the ion beam, some advantages of the present invention are partially and / or in some embodiments. When the ion beam approaches the target, the voltage of the target (and the electric field generated by the voltage) causes the energy of the ion beam to decrease. For example, the voltage of the target can be selected to (at least partially) offset the energy added to the ion beam provided by the extraction electrode, so that when the ion arrives at the target, the energy of the ion is reduced to thermal energy. In this case, the electronic stop (that is, the interaction between the ion and the target, and the interaction between the electron of the ion and the electron of the target substrate) and the nuclear stop (that is, the interaction between the nucleus of the ion and the nucleus of the target substrate) of the ion at the target are both reduced to zero or near zero levels. By reducing these interactions via the potential of the target, the ions are made to adhere to the target and form a film, rather than colliding with the target at high energy and sputtering or scattering.

[0027] The systems and methods described herein also provide a target material that is well suited for efficiently capturing ions incident thereon and being easily reduced to a residue having a high concentration of a desired isotope / atom (i.e., from an ion beam). Specifically, as described in detail below, a fiber lattice (e.g., a lattice, felt, mesh, etc. of carbon fibers (e.g., graphite fibers)) can be positioned so that an ion beam is incident thereon. For example, the fiber lattice captures ions and can easily burn (or undergo some other reaction) in the presence of oxygen to leave a residue having a high concentration of the desired isotope. During operation of the ion generation system, the fiber lattice can be rotated or translated relative to the beam to increase the collection capacity of the target before the operation needs to be suspended to harvest the desired isotope from the target. Therefore, the various concepts described below individually and collectively provide efficient collection of the desired isotope.

[0028] Reference now Figure 1, a block diagram of an ion generation system 100 according to an illustrative embodiment is shown. The ion generation system 100 includes an ion source 102, an extraction electrode 104, a magnetic analyzer 106, a mass resolving aperture 108, a target 110, and a voltage source 112 connected to a ground 114 and the target 110. The ion source 102, the extraction electrode 104, the magnetic analyzer 106, the mass resolving aperture 108, and the target 110 are arranged in sequence so that ions are generated at the ion source 102 and pass through the extraction electrode 104, the magnetic analyzer 106, and the mass resolving aperture 108 in sequence before reaching the target 110. As described in detail below, the ion generation system 100 is configured so that desired ions are efficiently collected at the target 110 as a constituted neutral material, which can be removed, stored, transported, etc., and ultimately used in some applications, such as healthcare applications.

[0029] The ion source 102 is configured to produce ions. For example, the ion source 102 can be configured as a Bernas or Freeman ion source, which includes a filament operable to emit electrons, which ionize the gas provided to the ion source 102, such as a heavy metal gas, such as ytterbium vapor. Other metals (Lu, Tc, etc. can also be used). The interaction between the electrons and the gas ionizes the gas to produce ions. In some embodiments, the ion source 102 produces positive ions (i.e., "cations": ions with positive polarity). In other embodiments, the ion source produces negative ions (i.e., "anions": ions with negative polarity). The ion source 102 includes an exit slit or hole so that ions can be extracted from the ion source 102. In some embodiments, the ion source 102 includes an auxiliary heater to protect the elements of the ion source 102 and improve the uniformity of the ions extracted from the ion source 102, for example, as described in detail in U.S. Provisional Patent Application No. 63 / 122,699 filed on December 8, 2020, the entire disclosure of which is incorporated herein by reference.

[0030] The extraction electrode 104 includes one or more electrodes configured and operated to provide an electric field to extract ions from the ion source 102. Because the ions have a charge of a first polarity (positive or negative in different embodiments), a voltage of opposite polarity at the extraction electrode 104 pulls the ions out of the ion source as an ion beam. The extraction electrode 104 may include one or more electrodes to accelerate the ion beam, decelerate the ion beam, shape the ion beam, aim the ion beam, etc. By providing an electric field that accelerates the ion beam away from the ion source 102, the extraction electrode 104 provides the ion beam with extraction energy of the same or similar magnitude as the voltage of the extraction electrode 104. For example, when the ion beam passes through the extraction electrode 104, an electrode with a voltage of 55 kV can provide an extraction energy of 55 kV to the ion beam (it should be noted that in this article, ion kinetic energy is generally expressed in volts, and one volt is equal to one joule / coulomb).

[0031] An ion beam having a high extraction energy is thus provided as an output of the extraction electrode 104. In various embodiments, the high extraction energy may be in a range between 20 kV and 80 kV, such as between 40 kV and 60 kV (e.g., 55 kV). In such embodiments, the voltage applied at the extraction electrode 104 may be selected to provide the ion beam with a desired extraction energy for a particular situation.

[0032] exist Figure 1 In the example of , the ion beam is passed from the extraction electrode 104 to the magnetic analyzer 106. In other embodiments, the magnetic analyzer 106 is omitted. The magnetic analyzer 106 is configured to provide a magnetic field that produces a magnetic force on the ion beam. The magnetic force on each ion can be approximately equal, but the ion beam can include ions of different isotopes, causing the mass of the ions to vary. The magnetic force provided by the magnetic analyzer 106 can cause the ions to be separated by mass. Therefore, after passing through the magnetic analyzer 106, different regions of the ion beam cross-section can include different isotopes, that is, ions of different masses.

[0033] exist Figure 1 In the figure, the ion beam is shown as being passed from the magnetic analyzer 106 to the mass resolving aperture 108, and the mass resolving aperture 108 is configured to prevent an undesirable subset of ions from passing through the mass resolving aperture 108 while allowing the desired ions to pass through the mass resolving aperture 108. Therefore, the mass resolving aperture 108 separates the desired ions or a high percentage of the desired ions. Specifically, the ions allowed to pass through the mass resolving aperture 108 are mainly ions of the desired isotope (or two desired isotopes), while the ions of one or more other isotopes are intercepted by the mass resolving aperture 108. This is achieved by positioning the mass resolving aperture 108 relative to the magnetic analyzer 106 to utilize the mass separation of isotopes achieved by the magnetic analyzer 106. In various embodiments, various geometric arrangements are possible. Therefore, in an example including the magnetic analyzer 106 and the mass resolving aperture 108, the ion beam arriving at the target 110 includes one or more high percentages of the desired isotopes and has a low percentage of different isotope ion contamination.

[0034] The ion beam from the mass resolving aperture 108 is incident on the target 110. The target 110 is configured to receive and collect ions of the ion beam. The target 110 may include a substrate material suitable for receiving and retaining ions, including making the ions as a film on the surface of the target 110 and / or embedded in the lattice structure of the target 110. For example, the substrate material of the target 110 may have a crystalline structure. As another example, the substrate material of the target 110 may include a carbon fiber material (e.g., a carbon fiber cloth). The material of the target 110 is also selected so that when ions are collected on the target 110, implanted into the target, or otherwise received at the target, the target 110 can be maintained at a substantially constant voltage. The material of the target 110 may be selected to help make the ions adhere to the target 110 or adhere to the target. The target 110 may be removable and replaceable in the ion generation system 100 to facilitate harvesting the ion material accumulated on the target 110 during the operation of the ion source 102.

[0035] Target 110 is shown coupled to voltage source 112, which is connected between target 110 and ground 114. Other components of ion generation system 100 include suitable electronic components, power supplies, etc. to achieve its operation. Voltage source 112 is configured to hold (place, establish, maintain, etc.) target 110 at a voltage (referred to herein as target voltage) of the same polarity as the ion beam. For example, Figures 2 to 3 As shown and discussed below, in the case where the ion source generates positive ions, the voltage source 112 provides a positive voltage to the target 110, and in the case where the ion source generates negative ions, the voltage source 112 provides a negative voltage to the target 110. In other embodiments, such as in Figures 2 to 3 In the example of FIG. 1 , target 110 is directly connected to ground so that target 110 is not biased.

[0036] The target voltage is preferably less than the extraction energy of the ion beam so that the ion beam can reach the target without being forced in the opposite direction by the target voltage, while being high enough to reduce the energy of the ion beam to a level small enough to minimize electron stopping and nuclear stopping of the ion beam at the target 110 (thereby minimizing scattering or sputtering that would otherwise be caused by high energy collisions between the ions and the target 110). For example, the target voltage can be less than the extraction energy by an amount corresponding to the thermal energy of the ions so that the energy of the ions is reduced to thermal energy just as the ions reach the target 110. In various embodiments, the target voltage is both less than the extraction energy and greater than 95% of the extraction energy, such as greater than 99% of the extraction energy (while also being less than the extraction energy). In some examples, the target voltage is about 100 V less than the extraction energy so that the ion beam has an energy of about 100 V when it reaches the target (e.g., the extraction energy minus the target voltage equals about 100 V). In one example, the extraction energy is 55 kV and the target voltage is 54.9 kV.

[0037] In some embodiments, the voltage source 112 and the target 110 are configured such that the voltage of the target 110 remains substantially constant throughout operation of the ion generation system 100 and when ions are collected on the target 110 (e.g., as a film on the target 110, embedded in the target 110) and are constituted as a neutral material (e.g., of a desired isotope). In some cases, to facilitate removal of constituted ionized material from the target 110, the target 110 can be removed from the ion generation system 100. In some such cases, the voltage source 112 is controlled to gradually reduce the target voltage to zero so that the target 110 can be disconnected from the voltage source 112 without destroying the ionized material collected thereon. In some embodiments, the target 110 (or a portion thereof) is removed for transport and further processing of the ionized material and replaced with a new target 110 (or a new portion thereof) for subsequent operation of the ion generation system 100. In other embodiments, ionized material may be removed from the target 110 and collected in a container (or other collection and holding device) so that the target 110 may be reused in subsequent operations of the ion generation system 100 to collect more ions.

[0038] Reference now Figure 2 , shows a schematic diagram of a target 110 and a voltage source 112 of an ion generation system 100 in an embodiment involving a positive ion beam 150 according to an exemplary embodiment. Figure 2 A positive ion beam 150 (ie, a positively charged ion beam) is shown aimed at and incident upon a target 110 .

[0039] Since the positive ion beam 150 has a positive polarity, the voltage of the target 110 also has a positive polarity. Figure 2 Target 110 is shown connected to the positive terminal of voltage source 112, while the negative terminal of voltage source 112 is connected to ground 114. Voltage source 112 maintains target 110 at a positive potential, ie, the same potential as the positive ion beam 150 polarity.

[0040] The positive potential of the target 110 provides an electric field that resists the movement of the ion beam 150 toward the target 110. The ion beam 150 must move through this electric field to reach the target 110. In this way, the kinetic energy of the ion beam 150 is converted into the potential of the ions in the electric field generated by the positive potential of the target 110. This can be thought of as being similar to the ions rolling "uphill" to reach the target 110. As described above, the target voltage is selected and maintained so that the positive ion beam 150 reaches a low energy, such as thermal energy, just as the positive ions reach the target 110. After being reduced to thermal energy, the positive ion beam 150 does not have additional kinetic energy that would cause it to move away from the target 110 or cause sputtering or scattering, and therefore, the ions of the positive ion beam 150 adhere to the target 110, for example, forming a positive ion film 151, such as Figure 2 shown.

[0041] Reference now Figure 3, shows a schematic diagram of a target 110 and a voltage source 112 of an ion generation system 100 in an embodiment involving a negative ion beam 152 according to an exemplary embodiment. Figure 2 A negative ion beam 152 (ie, a negatively charged ion beam) is shown aimed at and incident upon the target 110 .

[0042] Since the negative ion beam 152 has a negative polarity, the voltage of the target 110 also has a negative polarity. Figure 3 Target 110 is shown connected to the negative terminal of voltage source 112, while the positive terminal of voltage source 112 is connected to ground 114. Voltage source 112 maintains target 110 at a negative potential, ie, the same potential as negative ion beam 152 polarity.

[0043] The negative potential of the target 110 provides an electric field that resists the movement of the ion beam 152 toward the target 110. The ion beam 152 must move through this electric field to reach the target 110. In this way, the kinetic energy of the ion beam 152 is converted into the potential of the ions in the electric field generated by the negative potential of the target 110. This can be thought of as being similar to the ions rolling "uphill" to reach the target 110. As described above, the target voltage is selected and maintained so that the negative ion beam 152 reaches a low energy, such as thermal energy, just as the negative ion beam reaches the target 110. After being reduced to thermal energy, the negative ion beam 152 does not have additional kinetic energy that would cause it to move away from the target 110 or cause sputtering or scattering, and therefore, the ions of the negative ion beam 152 adhere to the target 110, for example, forming a negative ion film 153, such as Figure 3 shown.

[0044] The ion generation system 100 is thus configured to efficiently generate and collect ions as the ionized material of the composition. By setting the target 110 at the target voltage as described above, a high percentage of ions incident on the target 110 adhere to the target 110, such as forming a film on the target 110. Thus, the efficiency of the ion generation system 100 is improved by collecting a high percentage of the desired ions generated by the ion source 102. In addition, since the material is sputtered or scattered at a low rate or zero rate, it is also substantially prevented from accumulating on other unwanted surfaces in the ion generation system 100, thereby reducing downtime, cleaning, maintenance, etc. of the ion generation system 100. In addition, although the electronic stop or nuclear stop (i.e., collision between atoms) of high-energy ions at the target will cause the thermal energy of the target to increase greatly, the embodiments herein use the potential provided by the voltage source 112 to reduce the energy of the ions, thereby avoiding the accumulation of thermal energy at the target.

[0045] Reference now Figure 4 , shows a schematic diagram of an apparatus 200 including a vacuum chamber 202, an ion generation system 204, and a magnetic rotation device 206, according to some embodiments.

[0046] The ion generation system 204 is shown to include an ion beam generator 208 and a target 210. The ion beam generator 208 is configured to generate an ion beam and direct the ion beam to the target 210 so that the ion beam is incident on the target 210. For example, the ion beam generator 208 may include Figure 1 ion source 102, extraction electrode 104, magnetic analyzer 106 and / or mass resolving aperture 108. For example, target 210 may be configured to Figure 1 The target 110 is the same.

[0047] like Figure 4 As shown, the target 210 is coupled to the magnetic rotating device 206. The magnetic rotating device 206 includes an inner plate (first plate) 212, an outer plate (second plate) 214, and a motor 216. The inner plate 212 is located inside (inside, inside, contained therein) the vacuum chamber 202 and is positioned on the inner side 218 of the wall 220 of the vacuum chamber 202. The outer plate 214 is located outside (outside, outside, not contained therein) the vacuum chamber 202 and is positioned on the outer side 222 of the wall 220. The motor 216 is mechanically coupled to the outer plate 214. The target 210 is mechanically coupled to the inner plate 212.

[0048] The motor 216 is operable to drive the rotation of the outer plate 214. The motor 216 can be an electric motor, such as a stepper motor, which converts electricity into rotational movement. The motor 216 is coupled to the outer plate 214 so that the operation of the motor 216 applies a torque on the outer plate 214, causing the outer plate 214 to rotate around the axis of the outer plate 214. The rotary drive shaft of the motor 216 can be aligned with the axis of the outer plate 214 to directly transmit the torque to the outer plate 214, thereby causing the rotation of the outer plate 214. The motor 216 can be controllable to rotate the outer plate 214 at various speeds. In some embodiments, the motor 216 is operated to rotate the outer plate 214 at a speed of about one revolution per minute.

[0049] The outer plate 214 includes one or more magnets (eg, permanent magnets), and the inner plate 212 also includes one or more magnets (eg, permanent magnets) corresponding to the one or more magnets of the outer plate 214 . Figures 3 to 6 An exemplary arrangement of magnets in the inner plate 212 and the outer plate 214 is shown in and described with reference thereto. The magnets of the outer plate 214 and the inner plate 212 are arranged so that the outer plate 214 exerts an attractive force on the inner plate 212, and vice versa. For example, one or more magnets of the outer plate 214 can be arranged to have a positive magnetic polarity facing the wall 220, while one or more magnets of the inner plate 212 can be arranged to have a negative magnetic polarity facing the wall 220 (or vice versa), so that the magnets are attracted to each other and the magnetic force pulls the inner plate 212 and the outer plate 214 together. The magnets provide a magnetic field strong enough to exert an attractive force across the wall 220 of the vacuum chamber 202. In some embodiments, the wall 220 can be about half an inch thick.

[0050] Due to the magnetic attraction between the magnets of the outer plate 214 and the inner plate 212, the motor 216 rotates the outer plate 214 causing the inner plate 212 to rotate. In the example shown, due to the magnetic coupling between the inner plate 212 and the outer plate 214, the inner plate rotates to match the rotation of the outer plate. Thus, rotational movement and torque (e.g., angular kinetic energy) are transferred across the wall 220 of the vacuum chamber 202 without compromising the integrity of the hermetic seal of the vacuum chamber 202 (e.g., without requiring a mechanical joint between the inner plate 212 and the outer plate 214, which may be difficult to hermetically seal). Because, as Figure 4 As shown, target 210 is mounted on inner plate 212, and rotation of inner plate 212 causes rotation of target 210. Although the examples herein relate to rotation, in other embodiments, motor 216 is arranged to translate outer plate 214 (e.g., in one or two dimensions), thereby causing corresponding translation of inner plate 212 and target 210. Operation of motor 216 thus causes motion of target 210, such as rotation of target 210.

[0051] like Figure 4 As shown, the ion beam generator 208 directs the ion beam to the target 210 so that the ion beam is misaligned (offset, etc.) relative to the axis of rotation of the target 210. Therefore, when the target 210 is rotated by the operation of the magnetic rotating device 206, the point or area at which the ion beam is incident on the target 210 changes. The rotation of the target 210 over time causes the ion beam to be incident on different parts of the target 210 over time, thereby increasing the total area of ​​the target 210 exposed to the ion beam. The movement of the target 210 thereby allows the target 210 to be exposed to a larger area of ​​the ion beam and allows the target to capture ions and / or isotopes from the ion beam. Therefore, compared to an embodiment with a static target 210, the target 210 can capture more material, thereby allowing the device 200 to operate continuously for a longer time before the target is full (saturated, full capacity, etc.). Rotating the target can also help reduce temperature gradients on the target, which may be undesirable.

[0052] The magnetic rotation device 206 is also configured to provide heat transfer into or out of the vacuum chamber, for example to remove heat from the target 210 to manage its temperature. As shown, the inner plate 212 and the outer plate 214 are both positioned to contact the wall 220 of the vacuum chamber 202. The inner plate 212 and the outer plate 214 can include a material with high thermal conductivity (e.g., low resistance to heat flow therethrough), such as a metal such as steel. The wall 220 can be made of a similar material. The inner plate 212 and the outer plate 214 are in thermal contact with each other via the wall 220. This thermal contact is maintained by an attractive force between the magnets of the inner plate 212 and the outer plate 214, which can force the inner plate 212 and the outer plate 214 toward each other and contact the wall 220. The target 210 is shown as being located on the inner plate 212. A heat transfer path from the target 210 to the outer plate 214 is thereby provided.

[0053] In the illustrated embodiment, the apparatus 200 further includes a cooling system 224 in thermal communication with the outer plate 214. The cooling system 224 may include a refrigeration cycle (including, for example, a compressor, a condenser, an expansion valve, and an evaporator) configured to remove heat from the outer plate 214. For example, the cooling system 224 may provide a cooling fluid through one or more coils or other heat exchangers in thermal contact with the outer plate 214. The cooling of the outer plate 214 increases the heat flow away from the target 210, which may be desirable in embodiments where the collision of the ion beam with the target 210 provides thermal energy to the target 210. In other cases (e.g., other uses of the magnetic rotating device 206), the cooling system 224 may include or be replaced by a heating system configured to provide thermal energy to the outer plate 214 so as to transfer thermal energy (heat) to the vacuum chamber 202 via the inner plate 212.

[0054] Reference now Figure 5 , shows an exploded view of the target 110 (or target 210) or a portion thereof (e.g., a fiber lattice thereof) according to some embodiments. Figure 5 In the example of FIG. 1 , the target 110 includes a first lattice 400 and a second lattice 402, which form the target 110 into a fiber lattice. The first lattice 400 and the second lattice 402 can be stacked into layers to form the target 110. In other embodiments, other numbers of lattices (layers) (e.g., one, three, four, five, etc.) are included in the target 110. In various embodiments, the fiber lattice can be formed into a carbon felt or a carbon foam.

[0055] The first lattice 400 includes a plurality of fibers arranged in multiple directions (shown as two orthogonal directions). The plurality of fibers may be woven together or otherwise coupled to form the first lattice 400. The second lattice 402 also includes a plurality of fibers arranged in multiple directions (shown as two orthogonal directions) that are woven together or otherwise coupled to form the second lattice 402. The first lattice 400 and the second lattice 402 may be arranged relative to each other such that the fibers of the first lattice 400 are parallel to the fibers of the second lattice 402, or may be oriented differently such that the fibers of the first lattice 400 are at non-orthogonal angles relative to the fibers of the second lattice 402. In some embodiments, the first lattice 400 and the second lattice 402 appear substantially solid to the human eye, but are composed of fibers at a microscopic or smaller level.

[0056] The fibers of the first lattice 400 and the second lattice 402 may be made of carbon, for example Figure 5A first lattice 400 of carbon fibers and a second lattice 402 of carbon fibers are shown. In some embodiments, the fibers are made of graphite, for example such that some or all of the fibers of the first lattice 400 and the second lattice 402 are graphite fibers. The material of the fibers is preferably of high purity (e.g., greater than 95% carbon) such that when burned (in the presence of oxygen), the carbon fibers themselves leave little or no solid residue. When in a vacuum (e.g., when inside the vacuum chamber 202 during operation of the apparatus 200, there is substantially no oxygen present), the carbon fibers are configured to handle high temperatures (e.g., greater than 200° C., greater than 300° C., greater than 800° C.) without substantially deforming, melting, etc.

[0057] The first lattice 400 and the second lattice 402 are configured to capture ions incident thereon (eg, from Figure 4 ions of the ion beam provided by the ion beam generator 208 of the target). The arrangement of the plurality of fibers causes the ions to be deflected (scattered, collided, etc.) from the plurality of fibers as the kinetic energy of the ions decreases until the ions will reside at the target 110 (e.g., reduced to thermal energy) without being scattered from the target 110 after a single collision. The arrangement of the fibers is partially porous, allowing some ions to penetrate beyond the outer surface of the first lattice 400, thereby reducing the energy accumulated at the surface of the first lattice 400 and allowing the ions to be scattered multiple times without escaping the target 110 (e.g., evaporating from the target 110). Therefore, relative to a flat plate or block of material, the lattice structure provides an increased surface area and overlapping geometry, which can facilitate capturing a high percentage of ions incident on the target 110 (e.g., greater than 40%, greater than 90% in some arrangements). The first lattice 400 and the second lattice 402 thereby enable efficient collection of desired isotopes at the target 110.

[0058] The first lattice 400 and the second lattice 402 are also configured to burn (in the presence of oxygen) or otherwise react to leave (e.g., reduce to) a residue that includes a high concentration of the desired isotope. Figure 5 The fiber lattice configuration provides a target 110 having an increased surface area to mass ratio compared to a solid block or plate of carbon or graphite, which enables the first lattice 400 and the second lattice 402 to be burned relatively easily (e.g., compared to a solid block of graphite that would not normally burn). For example, during operation of the ion generation system 100, the target 110 captures the desired isotope (in Figure 5 400 and the second lattice 402 in the example of FIG. 40 ), while the target 110 is maintained in a vacuum without the presence of a large amount of oxygen (thereby preventing the target 110 from completely burning). The target 110 can then be removed from the vacuum (e.g., Figure 4The target 210 is removed from the vacuum chamber 202 in the example of ) for processing to extract isotopes from the fiber lattice. Outside the vacuum, there is oxygen, which can cause the carbon fibers to burn. The fiber lattice (e.g., the first lattice 400 and the second lattice 402) can then be burned to reduce the fiber lattice to a residue with a high concentration of the desired isotope. The carbon dissipates in the form of a gas after combustion, so that the remaining material has the desired isotope, which may be oxidized during the extraction process. For example, in some embodiments, ytterbium oxide powder (e.g., ytterbium oxide-176) is left as a powder (e.g., white powder) after the target is burned.

[0059] Reference now Figure 6 , shows a perspective view of a fiber lattice 500 of a target 110 (or target 210) according to some embodiments. The fiber lattice 500 can be used as Figure 5 The first lattice 400 and the second lattice 402 may be replaced, or in various embodiments may be replaced with Figure 5 The first lattice 400 and / or the second lattice 402 are used in combination.

[0060] like Figure 6 As shown, the fiber lattice 500 includes a plurality of fibers arranged in an entangled network such that the fiber lattice 500 can be characterized as an open-cell foam. Figure 5 In the example of FIG. 5 , the plurality of fibers may be carbon fibers and / or graphite fibers. The fiber lattice 500 is configured to capture ions (e.g., from Figure 2 ion beam generated by the ion beam generator 208 in the example of ), so that the desired isotope is collected in the fiber lattice 500. The fiber structure of the fiber lattice 500 can cause the ions to deviate from multiple fibers before settling in the fiber lattice 500, without being scattered from the fiber lattice 500 after one collision. The fiber lattice 500 also has a high surface area to mass ratio, which promotes easy combustion of the fiber lattice 500 to reduce the fiber lattice 500 to a residue with a high concentration of the desired isotope.

[0061] Reference now Figure 7 , shows a top view of a target 210 (or target 110) according to some embodiments. In the example shown, the target 210 is shown to include a first lattice 400 (which may include a second lattice 402 in some embodiments, for example, from Figure 7 from the perspective of being obscured behind the first lattice 400), a backplate 600, a mounting member 602 formed as a ring and positioned so that the first lattice 400 is located between the mounting member 602 and the backplate 600, and bolts 604 (or other connecting members, such as screws, clips, connectors, etc.) connecting the mounting member 602 to the backplate 600.

[0062] When the bolts 604 are tightened, the mounts 602 hold the first lattice 400 (or other fiber lattices, such as the fiber lattice 500) against the backing plate 600 so that the first lattice 400 is fixed in place relative to the backing plate 600. The bolts 604 can be loosened to release the first lattice 400 from the mounts 602 so that the first lattice 400 can be removed for harvesting the collected isotopes from the first lattice 400.

[0063] In some embodiments, the backplane 600 is coupled to Figure 4 The inner plate 212 of the magnetic rotating device 206 (actuator) is or is a part of it. In such embodiments, the operation of the motor 216 to drive the outer plate 214 causes the rotation of the inner plate 212, the backing plate 600, the mounting member 602 and the fiber lattice (e.g., the first lattice 400). As a result, the fiber lattice can be rotated about the axis, for example, to increase the surface area of ​​the fiber lattice (e.g., the first lattice 400) on which the ion beam is incident.

[0064] Figure 7 An example is shown in which an ytterbium ion beam having an energy of 60 kV is generated and directed toward the first lattice 400 such that the first lattice 400 captures the ytterbium ions / atoms. Figure 7 A combustion region 606 is shown where ytterbium is trapped by the first lattice 400. In the example shown, the ion beam causes partial combustion of the first lattice 400 during ion trapping. Figure 7 It is also shown that moving the first lattice 400 (eg, by rotating as described above) when an ion beam is incident upon the first lattice 400 can allow more of the first lattice 400 to be used to trap ions, thereby increasing the overall collection of desired isotopes / atoms.

[0065] Reference now Figure 8 , according to experimental results, the top of the first lattice 400 and the second lattice 402 (partially blocked by the first lattice 400) are shown. Figure 8 In the example of FIG. 7 , an ytterbium ion beam having an energy of about 5 kV is provided, which is incident on the first lattice 400 and the second lattice 402 (some ions pass through the first lattice 400 to the second lattice 402). The combustion region 700 shows where the ions are collected in the first lattice 400 and the second lattice 402. Figure 8 The experiment shows that ytterbium can be captured by the first lattice 400 and the second lattice 402. Figure 8 It is also shown that rotating the first lattice 400 and the second lattice 402 will expose more of the fiber lattice material to the ion beam to increase the overall collection of the desired isotope by the fiber lattice.

[0066] Reference now Fig. 9, according to another experimental result, the top of the first lattice 400 and the second lattice 402 (partially blocked by the first lattice 400) are shown. Fig. 9 In the example of FIG. 8 , an ytterbium ion beam having an energy of about 0.3 kV is provided, which is incident on the first lattice 400 and the second lattice 402 (some ions pass through the first lattice 400 to the second lattice 402). The combustion region 800 shows where the ions are collected in the first lattice 400 and the second lattice 402. Figures 8 to 9 In experiments with , a beam having an energy of approximately 0.3 kV provided increased capture (as evidenced by the larger combustion region 800 compared to combustion region 700) than a beam having an energy of approximately 5 kV. Figures 8 to 9 This illustrates the advantage of reducing the ion energy prior to collision with the target 110, as discussed above with reference to Figures 1 to 3 described. Fig. 9 It is also shown that rotating the first lattice 400 and the second lattice 402 will expose more fiber lattice material to the ion beam to increase the total collection of the desired isotope by the fiber lattice. Thus, the various features described herein facilitate efficient capture of the desired isotope / atom in the fiber lattice material, from which a residue rich in the desired particle can be readily obtained.

[0067] Although the above discussion gives a general overview of the physical principles associated with the operation of the ion generation system 100, the effect of the target voltage on the ion beam, etc., it should be understood that the behavior of the ion beam is complex and additional or alternative theoretical or experimental results may be used to provide further or alternative explanations of the various advantages of the systems and methods described herein. For example, experimental results have shown that providing a target voltage of the same polarity as the ion beam to the target 110 as described above provides the advantages described herein, and that the fiber lattice materials described herein provide efficient capture of desired isotopes (such as ytterbium-176).

[0068] As used herein, the terms "about," "approximately," "substantially," and similar terms are intended to have a broad meaning consistent with the common and recognized usage by those of ordinary skill in the art to which the subject matter of the present disclosure relates. Those skilled in the art who read the present disclosure should understand that these terms are intended to allow for the description of certain features described and claimed without limiting the scope of these features to the precise numerical values ​​or ideal geometries provided. Therefore, these terms should be interpreted as indicating that insubstantial or insignificant modifications or changes to the subject matter described and claimed are considered to be within the scope of the present disclosure as set forth in the appended claims.

[0069] As used herein, the term "connection" and its variations mean directly or indirectly connecting two components to each other. Such connection can be static (e.g., permanent or fixed) or movable (e.g., removable or releasable). Such connection can be achieved by directly connecting two components to each other, by using a separate intermediate member and any additional intermediate members connected to each other to connect two components to each other, or by using an intermediate member that is integrally formed into a single whole with one of the two components to connect two components to each other. If "connection" or its variations are modified by additional terms (e.g., direct connection), the general definition of "connection" provided above is modified by the simple language meaning of the additional terms (e.g., "direct connection" means that two components are connected without any separate intermediate member), resulting in a definition narrower than the general definition of "connection" provided above. Such connection can be mechanical, electrical or fluid.

[0070] References to the positions of elements herein (e.g., "top," "bottom," "above," "below") are only used to describe the orientation of various elements in the drawings. It should be noted that according to other exemplary embodiments, the orientation of different elements may be different, and such variations are also intended to be covered by the present disclosure.

[0071] Although the drawings and descriptions may illustrate a particular order of method steps, the order of these steps may be different from that depicted and described, unless otherwise specified above. In addition, two or more steps may be performed simultaneously or partially simultaneously, unless otherwise specified above. Such variations may depend on, for example, the software and hardware systems selected and the designer's choice. All such variations are within the scope of the present disclosure. Likewise, the software implementation of the described method may be accomplished using standard programming techniques with rule-based logic and other logic to accomplish various connection steps, processing steps, comparison steps, and decision steps.

Claims

1. A method for ion collection, comprising: accelerating a plurality of ytterbium ions toward a carbon fiber lattice; wherein at least a portion of the plurality of ytterbium ions are a plurality of ytterbium-176 ions; separating the plurality of ytterbium-176 ions from a plurality of ytterbium ions; as well as The plurality of ytterbium-176 ions are trapped in the carbon fiber lattice.

2. The method of claim 1, further comprising burning the carbon fiber lattice to obtain a residue comprising the plurality of ytterbium-176 ions.

3. The method of claim 1 , wherein separating the plurality of ytterbium-176 ions comprises: applying a magnetic field to the plurality of ytterbium ions using a magnetic analyzer, thereby mass separating the plurality of ytterbium ions; A mass resolving aperture located between the magnetic analyzer and the carbon fiber lattice is used to block a portion of the plurality of ytterbium ions, wherein the plurality of ytterbium-176 ions pass through the mass resolving aperture.

4. The method of claim 1, wherein accelerating the plurality of ytterbium ions toward the carbon fiber lattice comprises providing an energy greater than 100 V to the plurality of ytterbium ions.

5. The method of claim 1 , wherein trapping the plurality of ytterbium-176 ions in the carbon fiber lattice comprises decelerating the plurality of ytterbium-176 ions by deflecting the plurality of ytterbium-176 ions away from a plurality of carbon fibers of the carbon fiber lattice.

6. The method of claim 1, further comprising increasing an area of ​​the carbon fiber lattice that captures the plurality of ytterbium-176 ions by operating an actuator to rotate or translate the carbon fiber lattice.

7. The method of claim 1, wherein the carbon fiber lattice comprises multiple layers of fibrous carbon material.

8. The method of claim 1, wherein the carbon fiber lattice comprises carbon fibers arranged in multiple directions.

9. The method according to claim 1, wherein: Separating the plurality of ytterbium-176 ions from the plurality of ytterbium ions includes applying a magnetic field to the plurality of ytterbium ions using a magnetic analyzer, thereby mass separating the plurality of ytterbium ions.

10. The method according to claim 1, wherein: Separating the plurality of ytterbium-176 ions from the plurality of ytterbium ions includes blocking a portion of the plurality of ytterbium ions using a mass resolving aperture located between a magnetic analyzer and the carbon fiber lattice, wherein the plurality of ytterbium-176 ions pass through the mass resolving aperture.

11. The method according to claim 1, wherein: Trapping the plurality of ytterbium-176 ions in the carbon fiber lattice includes maintaining the carbon fiber lattice at a target voltage.

12. The method of claim 11, further comprising gradually decreasing the target voltage to zero before disconnecting the carbon fiber lattice from a voltage source.

13. The method of claim 1, further comprising removing the carbon fiber lattice and replacing the carbon fiber lattice with a new carbon fiber lattice.

14. The method of claim 1, further comprising removing the plurality of ytterbium-176 ions from the carbon fiber lattice; collecting the plurality of ytterbium-176 ions in a container; and reusing the carbon fiber lattice.

15. The method according to claim 6, wherein: Operating an actuator to rotate or translate the carbon fiber lattice further comprises mechanically coupling the carbon fiber lattice to an inner plate in the vacuum chamber and magnetically coupling the inner plate to an outer plate outside the vacuum chamber; Wherein the actuator drives a rotation or translation of the outer plate, which magnetically transfers the rotation or translation to the inner plate.

16. The method of claim 15, further comprising cooling the outer plate to increase heat flow away from the carbon fiber lattice.

17. The method of claim 15, further comprising heating the outer plate to increase heat flow to the carbon fiber lattice.

18. The method of claim 1, further comprising producing a plurality of ytterbium ions with an ion source.

19. The method according to claim 18, wherein: Producing the plurality of ytterbium ions includes emitting electrons from the filament to ionize ytterbium vapor.

Images