HK1158811B

HK1158811B - Device and method for producing medical isotopes

Info

Publication number: HK1158811B
Application number: HK11113063.2A
Authority: HK
Inventors: G．皮费尔
Original assignee: 阳光技术有限责任公司
Priority date: 2008-05-02
Filing date: 2009-05-01
Publication date: 2016-08-26

Description

Apparatus and method for producing medical isotopes

Information on related applications

This application claims priority from co-pending U.S. provisional application No.61/050,096 filed on 2.5/2008, according to 35u.s.c.section119(e), the contents of which are incorporated herein by reference in their entirety.

Background

The present invention relates to an apparatus and method for producing medical isotopes. More particularly, the present invention relates to an apparatus and method for producing neutron produced (neutrongated) medical isotopes with or without a subcritical reactor and Low Enriched Uranium (LEU).

Radioisotopes are commonly used by physicians in nuclear medicine. The most commonly used isotope of these isotopes is⁹⁹Mo。⁹⁹Most of the source of Mo is obtained from High Enriched Uranium (HEU). The high concentration of HEL used is sufficient to produce nuclear weapons. Export of HEU from the United states to facilitate production of the desired⁹⁹And Mo. It is desirable to produce what is needed without the use of an HEU⁹⁹Mo。

Disclosure of Invention

In one embodiment, the present invention provides a hybrid reactor for producing medical isotopes. The reactor includes: an ion source for generating an ion beam from a gas; a target chamber comprising a target that interacts with the ion beam to produce neutrons; and an activation chamber located proximate the target chamber and comprising a parent material that interacts with neutrons to produce the medical isotope by a fission reaction. An attenuator is positioned proximate the activation chamber and is selected to maintain the fission reaction at a subcritical level, a reflector is positioned proximate the target chamber and is selected to reflect neutrons toward the activation chamber, and a moderator (modulator) substantially surrounds the activation chamber, the attenuator, and the reflector.

In another embodiment, the present invention provides a hybrid reactor for producing medical isotopes. The reactor includes: including a fusion portion that substantially surrounds a long target path of a space. The fusion portion is used to generate a neutron flux within the target path. The reflector substantially surrounds the long target path and is arranged to reflect a portion of the neutron flux towards the space. An activation chamber is located within the space and includes parent material that reacts with a portion of the neutron flux to produce a medical isotope during the fission reaction. An attenuator is located within the activation chamber and is selected to maintain the fission reaction at a subcritical level, and the moderator substantially surrounds the activation chamber, the attenuator, and the reflector.

In another embodiment, the invention provides a method of producing a medical isotope. The method includes exciting a gas to generate an ion beam, accelerating the ion beam, and passing the accelerated ion beam through a long target path including a target gas. The target gas and ions react by fusion reaction to produce neutrons. The method also includes reflecting a portion of the neutrons with a reflector substantially surrounding the long target path, positioning a parent material within an activation chamber adjacent the long target path, and maintaining a fission reaction between the portion of the neutrons and the parent material to produce the medical isotope. The method also includes positioning an attenuator adjacent to the activation chamber and converting a portion of the neutrons into thermal neutrons within the attenuator to enhance the fission reaction within the activation chamber.

In yet another embodiment, the present invention provides a method of producing a medical isotope. The method includes exciting a gas to generate an ion beam, accelerating the ion beam, and passing the accelerated ion beam through a substantially linear target path including a target gas. The target gas and ions react by fusion reactions to produce free neutrons. The method also includes reflecting a portion of the free neutrons with a reflector located radially outward of the target path, positioning the parent material within an activation chamber adjacent the target path, and reacting the free neutrons and the parent material to produce the medical isotope without the use of fissile material.

Other aspects and embodiments of the invention will become apparent by consideration of the detailed description and accompanying drawings.

Drawings

The invention may be better understood and appreciated by reference to the detailed description of specific embodiments presented herein in conjunction with the appended drawings, of which:

FIG. 1 is a first view of a generator having a magnetic target chamber;

FIG. 2 is a second view of a generator with a magnetic target chamber;

FIG. 3 is a first view of a generator with a linear target chamber;

FIG. 4 is a first view of an ion source;

FIG. 5 is a cross-sectional view of an ion source;

FIG. 6 is a first view of the accelerator;

FIG. 7 is a cross-sectional view of the accelerator;

FIG. 8 is a first view of a differential pumping;

FIG. 9 is a cross-sectional view of a differential pump;

FIG. 10 is a first view of a gas filtration system;

FIG. 11 is a first view of a magnetic end station;

FIG. 12 is a cross-sectional view of a magnetic target chamber;

FIG. 13 is a first view of a linear end station;

FIG. 14 is a cross-sectional view of a linear target chamber, shown for production¹⁸F and¹³an exemplary isotope production system of N;

FIG. 15 is a first view of a generator with a linear target chamber and a synchronous high speed pump;

fig. 16 is a cross-sectional view of the synchronous high-speed pump in an extraction state, which allows the ion beam to pass;

fig. 17 is a cross-sectional view of the synchronous high-speed pump in a suppressed state, which does not allow the ion beam to pass therethrough;

FIG. 18 is a schematic diagram of one embodiment of a generator and controller with a linear target chamber and a synchronous high speed pump;

FIG. 19 is a graph showing that at 10 torr gas pressure and 25 deg.C³He gas pair²Stopping power of H ions, a plot of stopping power (keV/μm) versus ion energy (keV);

FIG. 20 is a graph showing that at 10 torr gas pressure and 25 deg.C³He gas pair²Stopping power of H ions, a plot of stopping power (keV/μm) versus ion energy (keV);

FIG. 21 shows 100mA of incident light at 10 Torr²H beam impact³A graph of the relationship between fusion reaction rate (reaction number/sec) and ion beam incident energy (keV) for He target;

FIG. 22 is a perspective view of a hybrid reactor including a fusion portion and a fission portion adapted to produce medical isotopes;

FIG. 23 is a perspective view of another version of a hybrid reactor including a fusion portion and a fission portion adapted to produce medical isotopes;

FIG. 24 is a side schematic view of a fission reactor, showing different layers of material;

FIG. 25 is a top schematic view of the fission reactor of FIG. 24, showing different layers of material;

FIG. 26 is a side schematic view of another fission reactor, showing different layers of material;

FIG. 27 is a top schematic view of the fission reactor of FIG. 26, showing different layers of material;

FIG. 28 is a side schematic view of another fission reactor showing different layers of material and being particularly suitable for use with a fission reactor⁹⁸Formation of Mo⁹⁹Mo; and

fig. 29 is a top schematic view of the fission reactor of fig. 28, showing different layers of material.

Detailed Description

Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of "including," "comprising," or "having" and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms "mounted," "connected," "supported," and "coupled" and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, "connected" and "coupled" are not restricted to physical or mechanical connections or couplings.

Before explaining at least one embodiment, it is to be understood that the invention is not limited in its application to the details illustrated by the examples below. Such descriptions and examples are not intended to limit the scope of the invention as set forth in the appended claims. The invention is capable of other embodiments or of being practiced or carried out in various ways.

In the present disclosure, various aspects of the invention may be set forth in a range format. It is to be understood that the description in range format is merely for convenience and brevity and should not be construed as a strict limitation on the scope of the invention. Thus, it will be understood by those skilled in the art that, for all purposes, particularly in terms of providing a written description, all ranges disclosed herein likewise encompass any possible subrange or combination of subranges thereof, as well as all integer and fractional values within that range. As just one example, the range of 20% to 40% may be broken down into 20% to 32.5% and 32.5% to 40%, 20% to 27.5% and 27.5% to 40%, etc. Any listed range can be readily considered as sufficiently describing the same range and allowing the same range to be broken down into at least two halves, three halves, four halves, five halves, ten halves, etc. As a non-limiting example, each range discussed herein may be readily broken down into a lower third, a middle third, an upper third, and so forth. In addition, it will be further understood by those within the art that all terms, such as "up to," "at least," "greater than," "less than," "more than," and the like, include the stated number and refer to ranges that can be resolved into subranges in turn, as described above. Likewise, all ratios disclosed herein also include all sub-ratios falling within the broader range of ratios. These are merely examples of what is specifically referred to. In addition, the phrases "range between" a first indicating number and "a second indicating number" and "range from" the first indicating number "to" the second indicating number "may be used interchangeably herein.

Terms such as "substantially", "about", "approximately", and the like, are used herein to describe features and characteristics that may deviate from ideal or stated circumstances without significantly affecting the performance of the device. For example, "substantially parallel" may be used to describe features that are ideally parallel, but may deviate by an angle of up to 20 ° as long as the deviation does not have a significant adverse effect on the device. Similarly, "substantially linear" may include a slightly curved path or a slightly convoluted path, so long as deviations from straightness do not significantly adversely affect device performance.

Fig. 22 shows an arrangement of a mixing reactor 5a that is well suited for producing medical isotopes. Before proceeding, it is to be noted that the term "hybrid reactor" as used herein refers to a reactor including a fusion portion and a fission portion. In particular, the reactor 5a shown is very suitable for being constructed of⁹⁸Mo or from LEU solutions⁹⁹And Mo. Hybrid reactor 5a includes a fusion portion 10 and a fission portion 8 that cooperate to produce the desired isotopes. In the structure shown in fig. 22, ten individual fusion portions 10 are used. Each fusion portion 10 is arranged as a magnetic fusion portion 10 and functions as a neutron source, as described with reference to fig. 1 and 2. Of course, other arrangements can use fewer fusion portions 10, more fusion portions 10, or other arrangements of fusion portions, as desired.

Fig. 23 shows another arrangement of a mixing reactor 5b that is well suited for producing medical isotopes. In the structure shown in fig. 23, the linear fusion portion 11 functions as a neutron source, as described with reference to fig. 3 and 4. In the structure shown in fig. 23, the linear fusion portions 11 are arranged such that five fusion portions 11 are located at one end of the fission portion 8 and five fusion portions 11 are located at the opposite end of the fission portion 8. Of course, other arrangements can be used, using other numbers of fusion portions 11 or other arrangements of fusion portions, if desired.

As shown in fig. 1-3, each fusion portion 10, 11 provides a compact device that can function as a high energy proton or neutron source. In one embodiment of the present invention,fusion portions 10, 11 utilize²H-³The He (deuterium-helium 3) fusion reaction produces protons, which can then be used to produce other isotopes. In another embodiment, the fusion portions 10, 11 are formed by changing the basic reactions²H-³H、²H-²H or³H-³The H reacts to act as a neutron source.

In view of the deficiencies inherent in conventional types of proton or neutron sources, the fusion portions 10, 11 provide novel high energy proton or neutron sources (sometimes collectively referred to herein as ion sources, but also referred to as particle sources) that can be used to produce medical isotopes. Each fusion portion 10, 11 produces a fusion reaction using a small amount of energy, which then produces energetic protons or neutrons that can be used for isotope production. The use of a small amount of energy may allow the device to be more compact than the conventional devices described above.

Each fusion portion 10, 11 suitably produces protons that can be used to produce other isotopes, including but not limited to¹⁸F、¹¹C、¹⁵O、¹³N、⁶³Zn、¹²⁴I and many other isotopes. By varying the fuel type, each fusion can also be used to generate high-flux homogeneous neutrons, which can be used to generate isotopes, including but not limited to¹³¹I、¹³³Xe、¹¹¹In、¹²⁵I、⁹⁹Mo (its decay is^99mTc) and many other isotopes. Also, each fusion portion 10, 11 provides a novel compact high energy proton or neutron source for, for example, producing medical isotopes, which has many advantages over the proton or neutron sources mentioned above.

Generally, each fusion portion 10, 11 provides a device for producing protons or neutrons, which in turn are suitable for producing various radionuclides (or radioisotopes). Referring to fig. 1 and 2, each magnetic fusion portion 10 includes a plasma source 20 (which may suitably include a radio frequency driven ion generator and/or antenna 24), an accelerator 30 (which is suitably driven by electrodes), and a target system (which includes a target chamber 60). In the case of proton-based radioisotope production, the apparatus may further include an isotope extraction system 90. An rf-driven plasma source 20 generates and aligns an ion beam along a predetermined trajectory, wherein the ion source 20 includes an inlet for entry of a first fluid. The electrode drive accelerator 30 receives and accelerates the ion beam to produce an accelerated ion beam. The target system receives the accelerated ion beam. The target system comprises a nuclear particle-derived (e.g., proton-derived or neutron-derived) target material that reacts with the accelerated ion beam and emits nuclear particles, i.e., protons or neutrons. For radioisotope production, the target system may have sidewalls that are permeable to nuclear particles. The isotope extraction system 90 is disposed near or within the target system and contains isotope-derived materials that react with nuclear particles to produce radionuclides (or radioisotopes).

It should be noted that although a radio frequency driven ion generator or ion source is described herein, other systems and devices are equally well suited for generating the desired ions. For example, other configurations may utilize a direct current arc ion source in place of or in addition to a radio frequency driven ion generator or ion source. Still other configurations may use hot cathode ion sources, cold cathode ion sources, laser ion sources, field emission sources and/or field evaporation sources in place of or in addition to direct current arc ion sources and/or radio frequency driven ion generators or ion sources. Thus, the present invention should not be limited to configurations using radio frequency driven ion generators or ion sources.

As discussed herein, the fusion portions can be arranged in a magnetic configuration 10 and/or a linear configuration 11. The six main parts or components of the device are connected as shown in fig. 1 and 2 for the magnetic configuration 10 and as shown in fig. 3 for the linear configuration 11. Each fusion portion (whether arranged in a magnetic arrangement or a linear arrangement) includes an ion source generally indicated at 20, an accelerator 30, a differential pumping system 40, a target system including a target chamber 60 for the magnetic configuration 10 or a target chamber 70 for the linear configuration 11, an ion confinement system generally indicated at 80, and an isotope extraction system generally indicated at 90. Each fusion portion can additionally include a gas filtration system 50. Instead of or in addition to the differential pumping system 40, each fusion section may also include a synchronous high speed pump 100. The pump 100 is particularly useful for linear configurations of the target chamber.

The ion source 20 (fig. 4 and 5) includes a vacuum chamber 25, a Radio Frequency (RF) antenna 24, and an ion injector 26 having an ion injector first stage 23 and an ion injector final stage 35 (fig. 6). A magnet (not shown) may be included to allow the ion source to operate in a high density helical mode to generate a high density plasma 22 for more ion flow. The field strength of the magnet is suitably from about 50G to about 6000G, suitably from about 100G to about 5000G. The magnets may be oriented to produce an axial field (north-south pole direction parallel to the ion beam path) or a cusp field (cuspfield) (north-south pole direction perpendicular to the ion beam path and inner poles alternating between north and south poles for adjacent magnets). The axial field may produce a helical pattern (dense plasma) while the cusp field may produce a dense plasma, but not a helical induction pattern. The gas inlet 21 is located at one end of the vacuum chamber 25 and the first stage 23 of the ion injector 26 is located at the other end. The gas inlet 21 provides one of the desired fuel types, which may include¹H₂、²H₂、³H₂、³He. And¹¹b, or may comprise¹H、²H、³H、³He and¹¹B. the gas flow at the inlet 21 is suitably regulated by a mass flow controller (not shown) which may be user controlled or automatically controlled. The radio frequency antenna 24 is suitably wound outside the vacuum chamber 25. Alternatively, the rf antenna 24 may be located inside the vacuum chamber 25. Suitably, the rf antenna 24 is in close proximity to the vacuum chamber such that the rf radiation emitted by the rf antenna 24 excites the contents (i.e. fuel gas) of the vacuum chamber 25, e.g. forming a plasma. The rf antenna 24 includes a tube 27 having one or more turns. The rf tube or wire 27 may be made of a conductive and bendable material, for example, copper, aluminum, or stainless steel.

The ion injector 26 comprises one or more shaping (shaped) stages (23, 35). Each stage of the ion ejector includes an accelerating electrode 32 suitably made of a conductive material, which may include metals and alloys to provide effective collimation of the ion beam. For example, the electrodes are suitably made of a conductive metal having a low sputtering coefficient, e.g., tungsten. Other suitable materials may include aluminum, steel, stainless steel, graphite, molybdenum, tantalum, and the like. The rf antenna 24 has one end connected to the output of an rf impedance matching circuit (not shown) and the other end connected to ground. The rf impedance matching circuit may frequency tune the antenna to match the desired impedance of the generator and establish rf resonance. The radio frequency antenna 24 suitably generates a wide range of radio frequency frequencies including, but not limited to, 0Hz to tens of kHz, to tens of MHz, to GHz or more. The rf antenna 24 may be water cooled by an external water cooler (not shown) so that it can tolerate high power dissipation with minimal change in resistance. The matching circuit in the ring of rf antennas 24 may be connected to an rf energy generator (not shown). The ion source 20, matching circuit and rf energy generator may be floating (insulated from ground) at the highest accelerator potential or slightly higher, and this potential may be obtained by electrical connection to a high voltage power supply. The rf energy generator may be remotely adjustable so that the beam intensity may be controlled by a user, or alternatively, by a computer system. A radio frequency antenna 24 connected to a vacuum chamber 25 suitably positively ionizes the fuel to produce an ion beam. Alternative means for generating ions are well known to those skilled in the art and may include microwave discharge, electron impact ionization and laser ionization.

Accelerator 30 (fig. 6 and 7) suitably includes a vacuum chamber 36 connected at one end to ion source 20 by an ion source docking flange 31 and at the other end to a differentially pumped system 40 by a differentially pumped docking flange 33. The first stage of the accelerator is also the final stage of the ion injector 26. At least one circular accelerating electrode 32 (suitably 3 to 50, more suitably 3 to 20) may be spaced along the axis of the accelerator vacuum chamber 36 and pass through the accelerator vacuum chamber 36 while allowing the vacuum envelope to be maintained. The accelerating electrodes 32 have holes through their centers (smaller than the accelerator chamber holes) and are suitably all at the longitudinal axis of the accelerator vacuum chamber (from the exit)From the source end to the differential pump end) to pass the ion beam. The minimum diameter of the aperture in the accelerating electrode 32 increases with the ion beam intensity or beams, and may be from about 1mm to about 20cm in diameter, suitably from about 1mm to about 6cm in diameter. The outer vacuum chamber 36, accelerating electrode 32, may be connected to an anti-corona ring 34, which reduces the electric field and minimizes corona discharge. The rings may be immersed in dielectric oil or insulating dielectric gas, e.g. SF₆In (1). Suitably, the differential pump docking flange 33 (which facilitates connection to the differential pump section 40) is located at the accelerator outlet.

Each accelerating electrode 32 of accelerator 30 may be biased by a high voltage power supply (not shown) or a resistive divider network (not shown), as is known to those skilled in the art. For most cases, the voltage divider can be the most suitable configuration due to its simplicity. In configurations having a resistive voltage divider network, the ion source terminal of the accelerator may be connected to a high voltage power supply and the second to last accelerator electrode 32 may be grounded. The intermediate voltage of the accelerator electrode 32 may be set by a resistor divider. The final stage of the accelerator is suitably negatively biased by the last accelerating electrode to prevent electrons from the target chamber from flowing back into the accelerator 30.

In an alternative embodiment, a linear accelerator (e.g., a radio frequency quadrupole) may be used in place of accelerator 30 as described above. The linear accelerator is less efficient and larger in size than the accelerator 30 described above. The linear accelerator may be connected to the ion source 20 at a first end and to the differentially pumped system 40 at the other end. The linac may use radio frequencies instead of dc and high voltage to achieve high particle energy, and they may be constructed as known in the art.

The differentially pumped system 40 (fig. 8 and 9) includes a pressure reducing baffle 42, which suitably separates the differentially pumped system 40 into at least one stage. Each pressure reduction barrier 42 suitably comprises a thin solid plate or one or more long thin tubes, typically 1 to 10cm in diameter with a small hole in the centre, suitably about 0.1mm to about 10cm in diameter, more suitably about 1mm to about 6 cm. Each stage comprises a vacuum chamber 44, an associated reduced pressure barrier 42 and a vacuum pump 17, each vacuum pump having a vacuum pump exhaust 41. Each vacuum chamber 44 may have one or more, suitably 1 to 4 vacuum pumps 17, depending on whether the vacuum chamber 44 is a 3, 4, 5 or 6 port vacuum chamber. Two of the ports of the vacuum chamber 44 are suitably oriented on a beamline (beamline) and are used for ion beam entry and exit from the differentially pumped system 40. The port of each vacuum chamber 44 may also be located at the same location as the pressure-reducing baffle 42. The remaining ports of each vacuum chamber 44 are connected to a vacuum pump 17, suitably by a cf (flat) flange, or may be connected to various instrumentation or control devices. Exhaust from the vacuum pump 17 is supplied through a vacuum pump exhaust 41 to an additional vacuum pump or compressor (not shown if required) and to the gas filtration system 50. Alternatively, this additional vacuum pump may be located between the gas filtration system 50 and the target chamber 60 or 70, if desired. Additional compression stages, if present, may be located between vacuum pump 17 and filtration system 50. One end of the differential pumping section is connected to the accelerator 30 through an accelerator docking flange 45, and the other end at the beam outlet 46 is connected to the target chamber (60 or 70) through a target chamber docking flange 43. The differentially pumped system 40 may also include turbulence generating devices (not shown) to disrupt laminar flow. The turbulence generating device may restrict fluid flow and may include surface protrusions or other features or combinations thereof to disrupt laminar flow. Turbulent flow is typically slower than laminar flow and thus can reduce the rate of fluid leakage from the target chamber into the differential pumping section.

In some configurations, the pressure reducing baffle 42 is replaced or enhanced by a plasma window (plasma window). The plasma window includes apertures similar to those used for the pressure relief baffle. However, a dense plasma is formed over the aperture to restrict gas flow through the aperture while still allowing the ion beam to pass through. A magnetic or electric field is formed in or near the aperture to hold the plasma in place.

The gas filtration system 50 is suitably connected at its vacuum pump isolation valve 51 to the vacuum pump exhaust 41 of the differentially pumped system 40 or to an additional compressor (not shown). The gas filtration system 50 (fig. 10) includes one or more pressure chambers or "traps" (13, 15) through which the exhaust of the vacuum pump exhaust 41 flows. The trap suitably captures fluid impurities that may escape the target chamber or ion source, where they may leak into the system from the atmosphere, for example. The trap can be cooled to cryogenic temperatures using liquid nitrogen (LN trap, 15). In this way, the cold liquid traps 13, 15 suitably liquefy and retain gases, such as atmospheric contaminants, in the traps 13, 15. After flowing through the one or more LN traps 15 connected in series, the gas suitably flows to a titanium getter (getter) trap 13, which adsorbs contaminating hydrogen gas, such as deuterium, that may escape the target chamber or ion source and otherwise contaminate the target chamber. The outlet of getter trap 13 is connected to a target chamber 60 or 70, suitably through a target chamber isolation valve 52 of gas filtration system 50. The gas filtration system 50 can be removed from the apparatus 10 as a whole if one wants to have the gas constantly flow into the system and exhaust it through the vacuum pump exhaust 41 to another vacuum pump exhaust (not shown) and out of the system. Without the gas filtration system 50, the operation of the apparatus 10 would not change substantially. The apparatus 10 as a neutron source may not include the getter trap 13 of the gas filtration system 50.

Vacuum pump isolation valve 51 and target chamber isolation valve 52 may facilitate isolation of gas filtration system 50 from the rest of the apparatus and may be connected to an external pump (not shown) through pump-out valve 53 when the trap is saturated with gas. Thus, if the vacuum pump isolation valve 51 and the target chamber isolation valve 52 are closed, the pump-out valve 53 can be opened to pump out impurities.

The end chamber 60 (fig. 11 and 12 for the magnetic system 10) or the end chamber 70 (fig. 13 and 14 for the linear system 11) may be filled with a target gas to a pressure of about 0 to about 100 torr, about 100 mtorr to about 30 torr, suitably about 0.1 to about 10 torr, suitably about 100 mtorr to about 30 torr. The particular geometry of the end station 60 or 70 may vary depending on its primary application and may include many variations. For a linear system 14, the end station may suitably be a cylinder having a length of about 10cm to about 5m and a diameter of about 5mm to about 100 cm. When used in a hybrid reactor, the target chamber is arranged to provide an activation column (activator) in its centre. The fusion portion is arranged to direct the beam through the target chamber, but outside the activation column. Thus, the beam travels substantially within the annular space. Suitably, for a linear system 14, the end station 70 may be about 0.1m to about 2m in length and may be about 30 to 50cm in diameter.

The target chamber 60 may resemble a thick pancake (pancake) with a height of about 10cm to about 1m and a diameter of about 10cm to about 10m for the magnetic system 12. Suitably, for the magnet system 12, the end station 60 may be about 20cm to about 50cm in height and about 50cm in diameter. For a magnetic target chamber 60, a pair of permanent or electromagnets (ion-confining magnets 12) may be located on the surface of the pancake, outside the vacuum wall or around the outer diameter of the target chamber (see fig. 11 and 12). The magnets are suitably made of materials including, but not limited to, copper and aluminum, or superconductors for electromagnets or NdFeB. The poles of the magnets are oriented such that they produce an axial magnetic field within the target chamber volume. The magnetic field is suitably controlled by means of a magnetic circuit comprising a high permeability magnetic material, such as 1010 steel, mu-metal or other material. The size of the magnetic target chamber and the magnetic beam energy determine the field strength according to equation (1):

for deuterons, where r is in meters, E is the beam energy in eV, and B is the magnetic field strength in gauss. The magnets may be oriented parallel to the flat surface of the pancake and polarized such that the magnetic field is perpendicular to the beam direction from the accelerator 30, i.e., the magnets may be mounted to the top and bottom of the target chamber to recirculate ions. In another embodiment using a magnetic end station 60, additional magnets are suitably provided on the top and bottom of the end station to create a mirror magnetic field at either end (top and bottom) of the magnetic end station, which creates a local area of stronger magnetic field at both ends of the end station, creating a mirror effect, which causes the ion beam to be reflected off the end away from the end station. These additional magnets, which generate the mirror magnetic field, may be permanent magnets or electromagnets. It is also desirable to provide a stronger magnetic field near the radial edge of the end station to produce a similar mirror effect. Also, shaped magnetic circuits (shaped magnetic circuits) or additional magnets may be used to provide the strong magnetic field required. One end of the target chamber is operatively connected to the differential pumping system 40 through the differential pumping docking flange 33, and the gas recirculation port 62 allows gas from the gas filtration system 50 to re-enter the target chamber. The target chamber may also include feed-through ports (not shown) to allow connection of various isotope production equipment.

In the magnetic configuration of the target chamber 60, the magnetic field confines ions in the target chamber. In the linear configuration of the target chamber 70, the injected ions are confined by the target gas. When used as a proton or neutron source, the target chamber may require safeguards to protect the operator of the device from radiation, which safeguards may be provided by a concrete wall suitably at least one foot thick. Alternatively, the apparatus may be stored underground or in a steel cement shelter, remote from the user, or water or other fluid, or a combination thereof, may be used as a protective measure.

The differential pumping system 40 and the gas filtration system 50 may be housed in the end station 60 or 70. The differential pumping system 40 is adapted to provide an ion beam and the gas filtration system 50 supplies a flow of filtered gas to fill the target chamber. Additionally, in the case of isotope production, a vacuum feedthrough (not shown) may be mounted to the target chamber 60 or 70 to allow the isotope extraction system 90 to be connected to the outside.

The isotope extraction system 90, including the isotope production system 63, can have any of a variety of configurations to provide parent compounds or materials and remove isotopes produced in or near the target chamber. For example, the isotope production system 63 can include an activation tube 64 (fig. 12 and 14) that is a close-wound solenoid that fits snugly within a cylindrical target chamber and has a wall 65. Alternatively, in the case of a pancake-type target chamber with an ion confinement system 80, it may include a solenoid (helix) covering the device along the circumference of the target chamber and two coils (spirals) located on the top and bottom surfaces of the pancake, respectively, and all connected in series. The walls 65 of the activation tube 64 used in these configurations are strong enough to prevent rupture, but thin enough that protons in excess of 14MeV (about 10 to 20MeV) can pass through them, while still retaining most of their energy. Depending on the material, the thickness of the tube wall is about 0.01mm to about 1mm, suitably about 0.1 mm. The tube wall is suitably made of a material that does not produce neutrons. The thin walled tube may be made of a material such as aluminum, carbon, copper, titanium, or stainless steel. A feed-through (not shown) may connect the activation tube 64 to the outside of the system, where the fluid enriched in the daughter compound or product compound may flow to a heat exchanger (not shown) for cooling and a chemical separator (not shown) to separate the daughter compound or product isotopic compound from the mixture of parent compound, daughter compound and impurities.

In another configuration, as shown in FIG. 15, a high speed pump 100 is located between the accelerator 30 and the target chamber 60 or 70. The high-speed pump 100 may replace the differential pumping system 40 and/or the gas filtration system 50. The high speed pump suitably includes one or more blades or rotors 102 and a timing signal 104 operatively connected to a controller 108. The high speed pump may be synchronized with the ion beam from the accelerator section such that when the gap 106 is aligned with the ion beam, one or more ion beams are allowed to pass through at least one gap 106 located between the blades 102 or in the blades 102. The timing signal 104 may be formed by placing one or more marks along the pump shaft or on at least one of the vanes. The label may be an optical, magnetic or other suitable label known in the art. The timing signal 104 can indicate the position of the vane 102 or gap 106 and whether a gap aligned with the ion beam exists to allow the ion beam to pass from the first stage 35 of the accelerator 30 through the high speed pump 100 to the end station 60 or 70. The timing signal 104 may be used as a gate pulse switch for the ion beam extraction voltage to allow the ion beam to exit the ion source 20 and accelerator 30 and enter the high speed pump 100. As it flows through the system from the ion source 20 to the accelerator 30, high speed pump 100 and end station 60 or 70, the beam may be on for a period of time while the ion beam is aligned with the gap 106, and then off before and during misalignment of the ion beam with the gap 106. The coordination of the timing signal 104 and the ion beam may be coordinated by a controller 108. In one embodiment of the controller 108 (fig. 18), the controller 108 may include a pulse processing unit 110, a high voltage isolation unit 112, and a high speed switch 114 to control the voltage of the accelerator 30 between a suppression voltage (ion beam off; difference may be 5-10kV) and an extraction voltage (ion beam on; difference may be 20 kV). The timing signal 104 suitably generates a logic pulse that is delayed in time or other logic or suitable means known in the art. The pulse processing unit 110 may alter the turbine of the high speed pump to accommodate the time delay, and the high speed switch 114 may be a MOSFET switch or other suitable switching technology known in the art. The high voltage isolation unit 112 may be a fiber optic connection or other suitable connection known in the art. For example, the timing signal 104 may indicate whether the gap 106 is present only once per revolution of the blade 102, and a single pulse may signal a set of electronics via the controller 108 to generate a set of n pulses per revolution of the blade, where there are n gaps in one revolution of the blade. Alternatively, the timing signal 104 may indicate to each of the m gaps, during a revolution of the blade whether a gap 106 exists, and the m pulses may be separately signaled by the controller 108 to a set of electronics to produce one pulse per revolution of the blade, where there are m gaps in one revolution of the blade. The logic pulse may be communicated or coordinated by the controller 108 to the first stage of the accelerator section 35 (ion extractor) such that the logic pulse triggers the first stage of the accelerator section 35 to change from a suppression state to an extraction state and vice versa. For example, if the accelerator is +300kV, the first stage of the accelerator 35 may be biased to +295kV when the gap 106 is not present in the high speed pump 100, so that the positive ion beam does not flow from +295kV to +300kV, and the first stage of the accelerator 35 may be biased to +310kV when the gap 106 is present in the high speed pump 100, so that the ion beam passes through the accelerator 30 and through the gap 106 in the high speed pump 100 to the target chamber 60 or 70. The voltage difference between the inhibit and extract states may be a small variation, for example from about 1kV to about 50kV, suitably from about 10kV to about 20 kV. Small voltage variations may facilitate fast transitions between the inhibit (fig. 17) and extract (fig. 16) states. Timing signal 104 and controller 108 may operate by any suitable means known in the art including, but not limited to, semiconductors and optical fibers. The time period for which the ion beam is switched on and off depends on factors such as the rotational speed of the blade 102, the number of blades or gaps 106, and the size of the blades or gaps.

Isotopes for use in PET scanning¹⁸F and¹³n can be generated from nuclear reactions within each fusion portion using the arrangement shown in fig. 12 and 14. These isotopes can be separated from their parent isotopes by proton bombardment (b)¹⁸O (for)¹⁸F) And¹⁶o (for)¹³N)) is generated. The parent source may be a fluid, such as water (H)₂ ¹⁸O or H₂ ¹⁶O) which can be flowed through the isotope production system by the action of an external pumping system (not shown) and reacted with energetic protons in the target chamber to produce the desired daughter compound. To generate to¹⁸F or¹³N, water (respectively, H)₂ ¹⁸O or H₂ ¹⁶O) flows through the isotope production system 63, the energetic protons produced by the fusion reaction described above can pass through the walls of the tube 64 and strike the parent compound, resulting in production¹⁸F or¹³N (p, α) in a closed system, for example, the isotope-enriched water may then be circulated through a heat exchanger (not shown) to cool the fluid and then into a chemical filter (not shown), such as an ion exchange resin, to separate the isotopes from the fluid the water mixture may then be recirculated into the target chamber (60 or 70), while the isotopes are stored in the filter, syringe, or other suitable means known in the art, until sufficient isotopology is generated for imaging or other procedures.

Although tubular coils are described above, there are many other coils that can be used to produce the same or other radionuclidesA geometric shape. For example, the isotope production system 63 may suitably be a parallel loop or a flat plate with ribs. In another embodiment, the water jacket may be attached to the vacuum chamber wall. For the¹⁸F or¹³N production coils may be replaced by any number of thin-walled geometries, including thin windows, or by solid materials that contain high oxygen concentrations and that may be removed and disposed of after deterioration. Other isotopes may be produced by other means.

With reference to fig. 1 and 3, the operation of the fusion portion will now be described. Before one of the fusion portions is operated, the corresponding target chamber 60 or 70 is operated by first making, for example³The target gas of He is suitably filled by flowing it through the ion source 20 with the power supply disconnected in advance, allowing the gas to flow through the apparatus 10 and into the target chamber. In operation, e.g.²H₂Enters the ion source 20 and is positively ionized by the rf field to form a plasma 22. As plasma 22 within vacuum chamber 25 diffuses toward ion injector 26, plasma 22 begins to be affected by the more negative potential in accelerator 30. This accelerates the cations toward the target chamber 60 or 70. The acceleration electrodes 32 of each stage (23 and 25) in the ion source 20 collimate one or more ion beams such that each ion beam has a nearly uniform ion beam pattern across the first stage of the accelerator 30. Alternatively, the first stage of the accelerator 30 may enable pulsing or on/off switching of the ion beam. As the beam continues through the accelerator 30 it acquires additional energy at each stage, reaching up to 5MeV, up to 1MeV, suitably up to 500keV, suitably 50keV to 5MeV, suitably 50keV to 500keV, and suitably 0 to 10Amps, suitably 10 to 100mAmps, on reaching the last stage of the accelerator 30. The potential is provided by an external power source (not shown) capable of generating the desired voltage. Some neutral gas from ion source 20 may also leak into accelerator 30, but the pressure in accelerator 30 is kept to a minimum by differentially pumped system 40 or synchronous high speed pump 100 to avoid overpressure and system failure. The beam continues at high velocity into the differential pump 40 where it passes through stages of lower pressure, short path length with minimal interaction. It follows from hereInto the target chamber 60 or 70, impinges on the high density target gas, suitably 0 to 100 torr, suitably 100 millitorr to 30 torr, suitably 5 to 20 torr, decelerates and undergoes a nuclear reaction. The emitted nuclear particles may be about 0.3MeV to about 30MeV protons, suitably about 10MeV to about 20MeV protons, or about 0.1MeV to about 30MeV neutrons, suitably about 2MeV to about 20MeV neutrons.

In the embodiment of the linear target chamber 70, the ion beam continues in an approximately straight line and strikes the high density target gas to cause nuclear reactions to occur until the ion beam stops.

In the embodiment of the magnetic target chamber 60, the ion beam is bent into an approximately helical path, with a radius of orbit (for deuterium ions,²H) given by equation (2):

wherein r is the radius of the track expressed in cm, T_iIs the ion energy in eV and B is the magnetic field strength in gauss. For a 500keV deuterium beam and a 5kG magnetic field strength, the orbit radius is about 20.4cm and is suitably adapted within a chamber having a radius of 25 cm. Although ion neutralization may occur, the rate at which re-ionization occurs is much faster, and the ions exist as ions for most of their time.

Once trapped in the magnetic field, the ions orbit until the ion beam stops, achieving very long path lengths within the short chamber. The magnetic end station 60 can also operate at lower pressures due to the increased path length relative to the linear end station 70. Thus, the magnetic end station 60 is a more suitable configuration. The magnetic end-station can be smaller than the linear end-station and still maintain a long path length because the beam can circulate many times within the same space. Fusion products will be more concentrated in the smaller chamber. As explained, the magnetic target chamber can operate at a lower pressure than the linear target chamber, relieving the pumping system because the longer path length can achieve the same total number of collisions with the lower pressure gas as with the short path length and high pressure gas of the linac chamber.

Gas can flow out of the target chamber and into the differentially pumped system 40 due to the pressure gradient between the accelerator 30 and the target chamber 60 or 70. The vacuum pump 17 can rapidly remove the gas, achieving a reduced pressure of about 10 to 100 times or more. This "blow-by" gas is then filtered and recirculated through the gas filtration system 50 and pumped back into the target chamber, providing more efficient operation. Alternatively, the high speed pump 100 may be oriented to direct the flow in a direction back to the target chamber, preventing gas from flowing out of the target chamber.

Although the invention described herein relates to a hybrid reactor, the fusion portion alone can be used to produce certain isotopes. If so desired, the isotope extraction system 90 described herein is inserted into the target chamber 60 or 70. The device allows the interaction of energetic protons with the parent nucleus of the desired isotope. For generation of¹⁸F or¹³N, the target may be water-based (for¹³N is¹⁶O, to¹⁸F is that¹⁸O) and will flow through the thin walled tube. The wall thickness is thin enough so that the 14.7MeV protons produced by the fusion reaction pass through them without losing too much energy, allowing them to change the parent isotope to the desired daughter isotope. Rich in¹³N or¹⁸The water of F is then filtered and cooled by an external system. Other isotopes may also be produced, for example¹²⁴I (made of¹²⁴Te or others),¹¹C (from)¹⁴N or¹¹B or others),¹⁵O (from¹⁵N or others) and⁶³and Zn. In configurations where fissile sections are used to produce the desired isotopes, the isotope extraction system 90 may be omitted.

If the desired product is protons for other purposes, the target chamber 60 or 70 may be connected to another device to provide high energy protons for these applications. For example, the fusion portion can be used as an ion source for proton therapy, in which a proton beam is accelerated and used to irradiate cancer cells.

If the desired product is a neutron, hardware such as the isotope extraction system 90 is not required, as the neutron can pass through the vacuum system walls with little attenuation. For neutron production, the fuel in the injector is converted to deuterium or tritium, wherein the target material is converted to tritium or deuterium, respectively. Can produce up to about 10¹⁵Neutron production of a number of neutrons per second or more. In addition, the getter trap 13 may be eliminated. The parent isotopic compound can be disposed about the target chamber 60 or 70 and the released neutrons can convert the parent isotopic compound to the desired daughter isotopic compound. Alternatively, the isotope extraction system may still or additionally be used within or near the target chamber. Moderators (not shown) that slow down neutrons may be used to increase the efficiency of neutron interaction. The moderator in neutronics terminology may be any material that slows the speed of neutrons. Suitable moderators can be made of low atomic weight materials that are unlikely to absorb thermal neutrons. For example, to composed of⁹⁸Production of Mo parent compound⁹⁹Mo, a water reducer may be used.⁹⁹Mo decays to^99mTc, which can be used in medical imaging procedures. Other isotopes may also be produced, for example¹³¹I、¹³³Xe、¹¹¹In and¹²⁵I. when used as a neutron source, the fusion portion may include a protective measure such as concrete or fluid (e.g., water) having a thickness of at least one foot to protect the operator from radiation. Alternatively, the neutron source may be stored underground to protect operators from radiation. The invention operates and operates in the same manner in the neutron mode as described above.

The fusion rate of the beam impinging on the thick target gas can be calculated. The incremental fusion rate for an ion beam impinging on a thick target gas is given by equation (3):

where df (E) is the fusion rate (number of reactions/sec), n, expressed as a differential energy interval dE_bIs the target gas density (number of particles/m)³)，I_ionIs an ion current (A), e is 1.6022 × 10^-19Coulomb/fundamental charge of a particle, σ (E) is the energy-dependent cross-section (m)²) Dl is the path length increment of particle energy E. Because the particle decelerates once within the target, the particle is only at energy E over the infinitesimal path length.

To calculate the total fusion rate from the beam stopped in the gas, equation (2) is put at E from the particle energy_iIs integrated over the entire particle path length from its maximum to the particle stop, as shown in equation (4):

wherein, F (E)_i) Is the initial energy E of the stop in the gas target_iThe total fusion rate of the beam. To solve this equation, the path length increment dl is found from the energy. The relationship is determined by the stopping power of the gas, which is an experimentally measured function, and can be fitted by various types of functions. These integrals are numerically solved because these fits, as well as the fits of the fusion cross-sections, tend to be complex. For use at 10 torr and 25 ℃ in³Data for deuterium rejection in He gas was obtained by the computer program "stoppingrangeofionsinmat" (SRIM; james ziegler, www.srim.org) and is shown in fig. 19.

Equations are used to predict the intermediate values. A polynomial fit of the tenth order was performed using the data shown in fig. 19. The coefficients are shown in table 1, and the resulting fitted curve using the best fit polynomial is shown in fig. 20.

TABLE 1

Coefficient of order
	10 -1.416621E-27
9 3.815365E-24
	8 -4.444877E-21
7 2.932194E-18
	6 -1.203915E-15
5 3.184518E-13
	4 -5.434029E-11
3 5.847578E-09
	2 -3.832260E-07
1 1.498854E-05
	0 -8.529514E-05

From these data, it can be seen that the fit is fairly accurate over the range of energies considered. This relationship allows the path length increment dl to be related to the energy interval increment by the polynomial listed in the table above. To solve this numerically, it is appropriate to choose a fixed length step or a fixed energy step and calculate how much energy the particle loses or how far it goes within that step. Since the fusion rate in equation (4) is expressed in terms of dl, a fixed length step is the method used. The recursive relationship for the particle energy E as it passes through the target is equation (5):

E_n+1＝E_n-S(E)*dl(5)

where n is the current step size (n-0 is the initial step size, E)₀Initial particle energy), E_n+1Is the energy in the next increment step, s (e) is the polynomial shown above relating particle energy to stopping power, dl is the size of the increment step. For the form of energy increment shown above, E is expressed in keV and dl in μm.

This formula gives a way to determine the energy of the particle as it passes through the plasma, which is important because it facilitates the estimation of the fusion cross-section at each energy and allows the fusion rate to be calculated in any incremental step. The fusion rate per step in the numerical case is given by equation (6):

to calculate the total fusion rate, the equation pair E_nUntil E is 0 (or n dl range) as shown in equation (7):

this fusion rate is referred to as "thick target yield". To solve this, the initial energy is determined and a small step size dl is selected. The fusion rate in the interval dl at full energy is calculated. Subsequently, the next longer energy is calculated and the process is repeated. This continues until the particles stop in the gas.

For a single ionized deuterium beam impinging on a 10 Torr helium-3 gas background at room temperature at an energy of 500keV and an intensity of 100mA, the calculated fusion rate is about 2x10¹³The number of polymeric molecules/second produced the same number of high energy protons (equivalent to 3. mu.A protons). Such levels are sufficient to produce medical isotopes, as known to those skilled in the art. FIG. 21 shows a graph of the fusion rate at which a 100mA incident deuterium beam strikes a 10 Torr helium-3 target.

The fusion portions described herein can be used in a variety of different applications. According to one configuration, the fusion section acts as a proton source to denature materials including nuclear waste and fissile material. The fusion portion can also be used to embed protons in the material to improve physical properties. For example, the fusion portion can be used for gemstone coloring. The fusion portion also provides a neutron source that can be used for neutron radiography. As a neutron source, the fusion portion can be used to detect nuclear weapons. For example, as a neutron source, the fusion portion can be used to detect specialized nuclear materials, which are materials that can be used to generate nuclear explosions, such as Pu,²³³U and is rich in²³³U or²³⁵U is used as a material. As a neutron source, fusion can detect subsurface features, including but not limited to tunnels, production wells, and subsurface isotope features, by generating neutron pulses and measuring the reflection and/or refraction of neutrons from materials. The fusion can be used as a neutron source in Neutron Activation Analysis (NAA), which can determine the elemental composition of a material. For example,NAA can be used to detect trace elements in the picogram range. As a neutron source, the fusion portion can also detect materials including, but not limited to, stealth materials, explosives, drugs, and biologics by determining the atomic composition of the material. The fusion portion can also be used as a driving device for a subcritical reactor.

The operation and use of the fusion portions 10, 11 is further illustrated by the following examples, which should not be construed as limiting the scope of the invention.

The fusion portions 10, 11 can be arranged in a magnetic configuration 10 to function as a neutron source. In this arrangement, initially, the system 10 is clean and empty, containing 10^-9At or below vacuum, the high speed pump 17 will increase to a certain speed (two stages, each stage being a turbomolecular pump). Approximately 25-30 standard cubic centimeters of gas (deuterium used to generate neutrons) will flow into the target chamber 60 to generate the target gas. Once the target gas is formed, i.e., when the specified volume of gas has flowed into the system and the pressure in the target chamber 60 reaches about 0.5 Torr, the valve will open, which allows a flow of deuterium from 0.5 to 1sccm (standard cubic centimeters per minute) to flow from the target chamber 60 into the ion source 20. This gas will be rapidly recirculated through the system, generating approximately the following pressures: in the ion source 20, the pressure is a few millitorr; in the accelerator 30, the pressure is about 20 μ torr; in the pump stage closest to the accelerator, the pressure is<20 micro torr; in the pumping stage closest to the target chamber, the pressure is about 50 mtorr; in the end station 60, the pressure is about 0.5 torr. After these conditions are established, the ion source 20 is energized (using deuterium) by bringing the rf power source (coupled to the rf antenna 24 through the rf matching circuit) to approximately 10-30 MHz. The power value will rise from zero to about 500W, resulting in a density of about 10¹¹Number of particles/cm³Dense deuterium plasma. The ion extraction voltage will be increased to provide the required ion current (about 10mA) and focusing. The accelerator voltage is then increased to 300kV, accelerating the ion beam through the throttle and into the target chamber 60. The end station 60 will be charged with a magnetic field of about 5000 gauss (or 0.5 tesla), which causes the ion beam to recirculate. The ion beam is cycled approximately 10 times before dropping to a negligibly low energy.

When recycled, the ion beam nucleates with the target gas, producing 4 × 10 for D¹⁰To 9 × 10¹⁰Number of neutrons per second. These neutrons will pass through the target chamber 60 and be detected using a suitable nuclear detection instrument.

Neutral gas leaking from the target chamber 60 into the differential pumping section 40 will flow through the high speed pump 17, through the cold traps 13, 15 and back into the target chamber 60. The cold traps 13, 15 will remove the heavier gases, which in time could contaminate the system with very small leaks.

The fusion portion 11 can also be arranged in a linear configuration to act as a neutron source. In this arrangement, initially, the system is clean and empty, containing 10^-9At or below vacuum, the high speed pump 17 will increase to a certain speed (three stages, where the two closest to the accelerator are turbo-molecular pumps and the third is another different pump, such as a roots blower). Approximately 1000 standard cubic centimeters of deuterium gas will flow into the target chamber 70 to produce the target gas. Once the target gas is formed, the valve will open, which allows a gas flow of 0.5 to 1sccm (standard cubic centimeters per minute) from the target chamber 70 into the ion source 20. This gas will be rapidly recirculated through the system, generating approximately the following pressures: in the ion source 20, the pressure is a few millitorr; in the accelerator 30, the pressure is about 20 μ torr; in the pump stage closest to the accelerator, the pressure is<20 micro torr; in the central pumping stage, the pressure is about 50 mtorr; in the pumping stage closest to the target chamber 70, the pressure is about 500 millitorr; in the target chamber 70, the pressure is about 20 torr.

After these conditions are established, the ion source 20 is energized (using deuterium) by bringing the RF power source (coupled to the RF antenna 24 through the RF matching circuit) to approximately 10-30 MHz. The power value will rise from zero to about 500W, resulting in a density of about 10¹¹Number of particles/cm³Dense deuterium plasma. The ion extraction voltage will be increased to provide the required ion current (about 10mA) and focusing. The accelerator voltage is then increased to 300kV, accelerating the ion beam through the throttle and into the target chamber 70. The target chamber 70 is a linear vacuum chamber in which the beam is descendingTo a negligible low energy by about 1 meter.

When passing through the target gas, the beam will undergo a nuclear reaction, yielding 4 × 10¹⁰To 9 × 10¹⁰Number of neutrons per second. These neutrons will pass through the target chamber 70 and be detected using a suitable nuclear detection instrument.

Neutral gas leaking from the target chamber 70 into the differential pumping section 40 will flow through the high speed pump 17, through the cold traps 13, 15 and back into the target chamber 70. The cold traps 13, 15 will remove the heavier gases, which in time could contaminate the system with very small leaks.

In another configuration, the fusion portion 10 is arranged in a magnetic configuration and can act as a proton source. In this configuration, initially, the system is clean and empty, containing 10^-9At or below vacuum, the high speed pump 17 will increase to a certain speed (two stages, each stage being a turbomolecular pump). Approximately 25-30 standard cubic centimeters of gas (approximately half each of the mixture of deuterium and helium-3 used to generate protons) will flow into the target chamber 60 to generate the target gas. Once the target gas is formed, i.e., when the specified volume of gas has flowed into the system and the pressure in the target chamber 60 reaches about 0.5 Torr, the valve is opened, which allows a flow of deuterium from 0.5 to 1sccm (standard cubic centimeters per minute) to flow from the target chamber 60 into the ion source 20. This gas will be rapidly recirculated through the system, generating approximately the following pressures: in the ion source 20, the pressure is a few millitorr; in the accelerator 30, the pressure is about 20 μ torr; in the pumping stage closest to accelerator 30, the pressure is<20 micro torr; in the pumping stage closest to the target chamber 60, the pressure is about 50 millitorr; in the end station 60, the pressure is about 0.5 torr. After these conditions are established, the ion source 20 is energized (using deuterium) by bringing the rf power source (coupled to the rf antenna 24 through the rf matching circuit) to approximately 10-30 MHz. The power value will rise from zero to about 500W, resulting in a density of about 10¹¹Number of particles/cm³Dense deuterium plasma. The ion extraction voltage will be increased to provide the required ion current (about 10mA) and focusing. The accelerator voltage is then increased to 300kV, accelerating the ion beam through the throttle and into the target chamber 60. The target chamber 60 is filled with about 5A magnetic field of 000 gauss (or 0.5 tesla) which causes the ion beam to recirculate. The ion beam is cycled approximately 10 times before dropping to a negligibly low energy.

When recycled, the ion beam nuclear reacts with the target gas to produce 1 × 10¹¹To up to about 5 × 10¹¹Number of protons per second. These protons will pass through the tubes of the isotope extraction system and be detected using a suitable nuclear detection instrument.

In another configuration, the fusion portion 11 is arranged in a linear configuration and can act as a proton source. In this configuration, initially, the system is clean and empty, containing 10^-9At or below vacuum, the high speed pump 17 will increase to a certain speed (three stages, where the two closest to the accelerator are turbo-molecular pumps and the third is another different pump, such as a roots blower). Approximately half of each of the approximately 1000 standard cubic centimeters of deuterium and helium-3 gas will flow into the target chamber 70 to produce the target gas. Once the target gas is formed, the valve will open, which allows a gas flow of 0.5 to 1sccm (standard cubic centimeters per minute) from the target chamber 70 into the ion source 20. This gas will be rapidly recirculated through the system, generating approximately the following pressures: in the ion source 20, the pressure is a few millitorr; in the accelerator 30, the pressure is about 20 μ torr; in the pumping stage closest to accelerator 30, the pressure is<20 micro torr; in the central pumping stage, the pressure is about 50 mtorr; in the pumping stage closest to the target chamber 70, the pressure is about 500 millitorr; in the target chamber 70, the pressure is about 20 torr.

After these conditions are established, the ion source 20 is energized (using deuterium) by bringing the rf power source (coupled to the rf antenna 24 through the rf matching circuit) to approximately 10-30 MHz. The power value will rise from zero to about 500W, resulting in a density of about 10¹¹Number of particles/cm³Dense deuterium plasma. The ion extraction voltage will be increased to provide the required ion current (about 10mA) and focusing. The accelerator voltage is then increased to 300kV, accelerating the ion beam through the throttle and into the target chamber 70. The target chamber 70 is a linear vacuum chamber in which the beam travels approximately 1 meter before dropping to a negligible low energy.

When passing through the target gas, the beam will undergo a nuclear reaction, yielding 1 × 10¹¹To up to about 5 × 10¹¹Number of protons per second. These protons will pass through the walls of the isotope extraction system and be detected using a suitable nuclear detection instrument.

In another configuration, the fusion portions 10, 11 are arranged in a magnetic or linear configuration and serve as a source of neutrons for isotope production. The system will operate in the manner discussed above with reference to the magnetic or linear end station 70. Solid test specimens, e.g. mother materials⁹⁸A solid foil of Mo is placed against the target chamber 60, 70. Neutrons generated in the target chamber 60, 70 will pass through the wall of the target chamber 60, 70 and interact with⁹⁸Mo parent material reacts to produce⁹⁹Mo, which can decay to metastable⁹⁹Tn。⁹⁹Mo will be detected using appropriate instrumentation and techniques known in the art.

In other configurations, the fusion portions 10, 11 are arranged as a source of protons for isotope production. In these configurations, the fusion portions 10, 11 operate as described above with reference to the magnetic target chamber 60 or the linear target chamber 70. The system includes an isotope extraction system located within the target chamber 60, 70. Parent material (e.g., comprising H)₂ ¹⁶O water) will flow through the isotope extraction system. Protons generated in the target chamber will pass through the walls of the isotope extraction system and¹⁶o reacts to produce¹³And N is added. Extraction from parent or other materials using ion exchange resins¹³And N, a product material.¹³N will be detected using appropriate instrumentation and techniques known in the art.

In summary, each fusion portion 10, 11 provides, among other things, a compact high-energy proton or neutron source. The above description merely illustrates the principle of the fusion portions 10, 11. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the fusion portions 10, 11 to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, as required or desired.

As shown in fig. 22 and 23, the fissile sections 400a, 400b of the hybrid reactors 5a, 5b are located adjacent to the target chambers 60, 70 of the multiple fusion sections 10, 11. The fusion portions 10, 11 are arranged such that a reaction space 405 is defined within the target chambers 60, 70. In particular, ion trajectories within the target chamber 60, 70 do not enter the reaction space 405, and therefore, the material to be irradiated may be placed within the space. In order to further increase the neutron flux, a plurality of fusion portions 10, 11 are superimposed on one another, wherein advantageously up to ten neutron sources. As shown in fig. 22, the hybrid reactor 5a includes fission portions 400a and fusion portions 10 in a magnetic arrangement to create a plurality of stacked target chambers 60 that are pancake shaped but in which the ion beam flows along a circular path. Thus, to place the material to be irradiated, a reaction space 405 within the annular path may be used.

Fig. 23 shows a linear arrangement of fusion portions 11 coupled to fission portion 400b to define hybrid reactor 5 b. In this configuration, the ion beam is directed along a plurality of substantially parallel, spaced apart linear paths positioned in the annular target chamber 70. The reaction space 405 located in the annular target chamber 70 is suitable for placing the material to be irradiated. It is therefore apparent that the fissile sections 400a, 400b described with reference to fig. 24-29 can be used in a magnetic or linear configuration of the fusion sections 10, 11.

Referring to fig. 22 and 23, fissile sections 400a, 400b include a substantially cylindrical activation column 410 (sometimes referred to as an activation cell) located in a canister 415 containing moderator/reflector materialThe agent/reflector material is selected to reduce radiation escaping from the fissures 400a, 400b during operation. The activation column 410 is positioned in the target chamber 60, 70 where the fusion reaction takes place. The end station 60, 70 is about 1m high. The beryllium layer 420 can surround the target chamber 60, 70. The moderator is typically D₂O or H₂And O. Additionally, a gas regeneration system 425 is located on the top of the tank 415. An aperture 430 located in the center of the gas regeneration system 425 extends into the activation column 410 where a subcritical assembly 435 comprising the LEU mixture and/or other parent material may be located. In a preferred construction, the aperture 430 has a radius of about 10cm and a length of about 1 m.

Each fusion portion 10, 11 is arranged to emit high energy neutrons from the target chamber. Neutrons emitted by the fusion portions 10, 11 are emitted isotropically, while high-energy neutrons entering the activation column 410 pass through the activation column with little interaction. The target chamber is surrounded by 10-15cm of beryllium 420, which multiplies the fast neutron flux by a factor of about 2. The neutrons then enter the moderator where they are slowed to thermal energy and reflected back into the activation chamber 410.

It is estimated that the neutron production rate from this configuration is about 10¹⁵n/s (estimated source intensity of 10 for a single fusion portion 10, 11 operating at 500kV and 100mA¹⁴n/s and ten such devices in the illustrated configuration), the calculated total volumetric flux in the activation chamber 410 is 2.35 × 10 with an uncertainty of 0.0094¹²n/cm²Heat flux (less than 0.1eV) 1.34 × 10 with uncertainty 0.0122/s¹²n/cm²And s. As described below, this neutron rate is greatly increased by the presence of LEU.

As described with reference to fig. 1 and 3, the fusion portions 10, 11 can be arranged in a magnetic arrangement or a linear arrangement. A practical advantage of the magnetic arrangement of the fusion portions 10, 11 is that they achieve long path lengths in lower pressure gases. To effectively use the linear configuration, the target gas must be cooled and the pressure must be maintained at a high level. One example of such a configuration has several deuterium beam lines launched axially into the target chamber 70 from above and below the device, as shown in fig. 23. Although the target chamber 70 may need to operate at pressures up to 10 torr in order to achieve this successfully, it is a simpler, efficient method for the fusion portions 10, 11.

The main simplification of the linear configuration is that the components required to establish the magnetic field to direct the beam in a spiral or helical manner are not required. The lack of components required to create the magnetic field makes the device less expensive and the magnet does not function in attenuating the neutron flux. However, in some configurations, the magnetic field is used to collimate the ion beam generated by the linear arrangement of the fusion portions 11, as described below.

In order to produce as end product a product having a high specific activity⁹⁹Mo, which should be made of chemically different materials so that it can be easily separated. The most common way is by neutron bombardment²³⁵And U is cracked. The fusion portions 10, 11 described previously produce enough neutrons to produce a large number without additional reactions⁹⁹Mo, but if already present in the device²³⁵U, significantly, is placed in providing neutron multiplication and providing for production⁹⁹The target structure of Mo. Neutrons produced by fission can be enhanced⁹⁹The specific activity of Mo plays an important role and can improve the total system⁹⁹And (6) Mo output. Multiplication factor k_effInvolving multiplication by the formula 1/(1-k)_eff). This product result can lead to an increase in the overall yield and specific activity of the final product by as much as 5-10 fold. k is a radical of_effIs a strong function of LEU density and moderator configuration.

May exist of and H₂O (or D)₂O) several subcritical configurations of subcritical assemblies 435 composed of bound LEU (20% rich) targets. All of these configurations are inserted into the previously described reaction chamber space 405. One part of the construction comprises a LEU foil, an aqueous solution of a uranium salt dissolved in water, an encapsulated UO₂Powders, and the like. Aqueous solutions are very popular due to the excellent moderating effect on neutrons, but present challenges from a criticality standpoint. To ensure subcritical operating conditions, the critical constant k_effShould remain in0.95 or less. Other control features can be easily added to reduce k when obtaining a critical state_eff. These control features include, but are not limited to, control rods, injectable inhibitors, or pressure relief valves that empty the moderator and reduce criticality.

Aqueous solutions of uranium offer great advantages for downstream chemical processing. In addition, they are easy to cool and provide an excellent combination of fuel and moderator. With uranium nitrate solution-UO₂(NO₃)₂Initial studies were conducted, but other solutions such as uranium sulfate and the like are also contemplated. In one configuration, the salinity of the solution is about every 100gH₂O contained 66g of salt. The solution is located in the activation chamber 410 as shown in fig. 24 and 25. In addition to the solution, at the center of the activation chamber 410 filled with pure water is a cylinder 500 having a smaller diameter. The water cylinder body allows k_effThe value of (c) is reduced so that the device remains subcritical while still allowing the use of large quantities of LEU solution.

In the aqueous solution layout schematic shown in fig. 24 and 25, the centermost barrel 500 contains pure water and is surrounded by an aqueous mixture of uranium nitrate contained between a tube and a cylindrical wall 505 that cooperate to define a substantially annular space 510. The target chamber 60, 70 is the closest outer layer and is likewise annular. The pure water, the water mixture of uranium nitrate, and the target chamber 60, 70 are surrounded by a Be multiplier/reflector 420. In this case, the outermost layer 520 is a large amount D contained in the tank 415₂O。D₂The O acts as a moderator to reduce radiation leakage from the fissures 400a, 400 b. Fig. 26-29 show similar structural components, but containing different materials within a portion or all of the volume, as shown in these particular figures.

A common method of irradiating uranium is to form it into pellets of uranium dioxide or to load uranium dioxide powder into a container. They are inserted into the reactor and irradiated prior to removal and processing. Despite the UO now in use₂The powder utilizes HEU, but preferably LEU is used. In a preferred configuration, the use provides K_eff<LE of 0.95U and H₂A mixture of O.

FIGS. 26 and 27 show an activation column 410, which includes a position D₂UO in O homogeneous solution₂. The central cylinder 500 in this configuration is filled with H₂The same is true for O525, the outermost layer 530 (only a portion of which is shown). First annular space 535 contains 18% LEU (20% enriched) and 82% D₂A solution of O. The second annular layer 540 is substantially evacuated, consistent with the fusion portion target chambers 60, 70. The central cylinder 500, the first annular space 535 and the second annular space 540 are surrounded by a Be layer 420, which acts as a multiplier and neutron reflector.

In another configuration, the extraction of uranium is carried out by chemically dissolving the LEU foil in a modified Cintichem process⁹⁹And Mo. In this method, a thin foil containing uranium is placed in a high flux region of a nuclear reactor, irradiated for a period of time, and subsequently removed. The foils are dissolved in various solutions and treated by a variety of chemical methods.

From the safety, non-diffusion and health perspectives, produce⁹⁹A suitable method for Mo is to use the parent material⁹⁸Mo undergoes an (n, gamma) reaction. This occurs without contamination by plutonium or other cracked products⁹⁹And Mo. Production by this method does not require a stable feed of any form of uranium. Has the disadvantage that it is difficult to make⁹⁹Mo Slave master⁹⁸Mo segregation, which results in⁹⁹Low specific activity of Mo in the generator. Furthermore, if rich is used⁹⁸Mo is relatively expensive. However, in improving the low specific activity⁹⁹High purity of Mo extraction^99mConsiderable progress has been made in new elutriation methods for Tc, which will become a cost-effective option in the near future. For such production in the hybrid reactors 5a, 5b shown here, a fixed subcritical assembly 435 of LEU may be used to increase neutron flux (mostly UO)₂) But can be connected with a nut⁹⁸And isolating Mo. The subcritical assembly 435 is still inside the fusion portion 10, 11,⁹⁹the Mo activation column is located within the subcritical apparatus 435.

In a preferred construction of the device according to the invention,⁹⁸mo occupies 20% (by volume) of the activated column 410. As shown in FIGS. 28 and 29, the centermost cylinder 500 contains 20%⁹⁸Mo and H₂A homogeneous mixture of O. The first annular layer 555 includes a subcritical arrangement 435 and is comprised of 18% LEU (20% enriched)/D₂And O mixture. The second annular layer 560 is substantially evacuated, consistent with the fusion portion target chambers 60, 70. The central cylinder 500, the first annular space 555 and the second annular space 560 are surrounded by a Be layer 420, which acts as a multiplier and neutron reflector. The outermost layer 570 (only a portion of which is shown) contains water, which reduces the amount of radiation escaping from the fissures 5a, 5 b.

For the LEU case, 10 at fusion portions 10, 11¹⁵In the case of n/s operation, the productivity and specific activity of Mo are determined by calculating 6% of the fission yield. Also calculate K for various configurations_eff. Table 1 summarizes the results of these calculations. Is formed by⁹⁸Production of Mo, determined using (n, γ) counts (tally)⁹⁹Productivity of Mo. The table below shows the production rates for different target configurations in the mixing reactors 5a, 5 b.

Despite the generation of⁹⁹The specific activity of Mo is relatively stable for all sub-critical cases, but some configurations can yield much higher overall productivity. This is because these configurations allow for the use of significantly greater amounts of parent material. It is also worth noting that⁹⁹In terms of the total amount of Mo, is composed of⁹⁸Mo production⁹⁹Mo is as good a process as produced by LEU. However, the LEU method is easier to implement because it makes it easier to do⁹⁹Separating Mo from fission products (and separating it from fission products⁹⁸Mo separation) which allows obtaining a high specific activity after separation⁹⁹Mo。

In use⁹⁸Mo production⁹⁹In the Mo configuration, the subcritical assembly 435 may be completely removed. However,the specific activity of the final product is much lower if the subcritical assembly 435 is removed. However, there are some cases that show that advanced generators can be utilized by⁹⁸Low specific activity resulting from Mo irradiation. The specific activity produced by the mixing reactors 5a, 5b without subcritical multiplication is sufficiently high for some processes. Furthermore, the use of several production facilities that allow for a non-fission process may still suffice for the United states⁹⁹Total requirement of Mo.

For example, in one configuration of a reactor where fusion only occurs, the subcritical assembly 435 is omitted, and⁹⁸mo is located within the activation column 410. To improve⁹⁹Production of Mo, using a higher energy ion beam produced by the linear arrangement of the fusion portion 11. The ion beam is preferably operated at a power level of about ten times that required by the above-described structure. To this end, a magnetic field is established to collimate the beam and to suppress unwanted scattering of the beam. The magnetic field is arranged such that it is parallel to the beam and substantially surrounds the accelerator 30 and the pumping system 40, but does not necessarily extend into the end station 70. Using this arrangement provides the required neutron flux without the multiplication effect produced by the subcritical assembly 435. One advantage of this arrangement is that uranium is not required to produce the required isotopes.

Thus, the present invention provides, among other things, a novel and useful hybrid reactor 5a, 5b for use in the production of medical isotopes. The structure of the mixing reactors 5a, 5b as described above and shown in the figures is given by way of illustration only and not as a limitation of the inventive concept and principles. Various features and advantages of the invention are set forth in the following claims.

Claims

1. A hybrid reactor for producing medical isotopes, the hybrid reactor comprising:

an ion source for generating an ion beam from a gas;

a target chamber comprising a target that interacts with the ion beam to produce neutrons; and

an activation chamber located proximate to the target chamber and comprising a parent material that interacts with neutrons to produce the medical isotope by a fission reaction;

an attenuator positioned proximate the activation chamber and selected to maintain the fission reaction at a subcritical level;

a reflector positioned proximate the target chamber and selected to reflect neutrons toward the activation chamber; and

a moderator substantially surrounding the activation chamber, the attenuator, and the reflector.

2. The hybrid reactor of claim 1, wherein the ion beam is generated using radio frequency resonance.

3. The hybrid reactor of claim 1, further comprising an accelerator positioned between the ion source and the target chamber for accelerating ions of the ion beam.

4. The hybrid reactor of claim 1, wherein the gas comprises one of deuterium and tritium and the target comprises the other of deuterium and tritium.

5. The hybrid reactor of claim 1, wherein the target chamber defines a substantially linear long target path.

6. The hybrid reactor of claim 5, further comprising at least one magnet positioned to define a magnetic field that collimates the ion beam within at least a portion of the long target path.

7. The hybrid reactor of claim 1, wherein the target chamber defines a substantially helical long target path.

8. The hybrid reactor of claim 7, further comprising at least one magnet positioned to define a magnetic field that directs the ion beam along a helical path.

9. The hybrid reactor of claim 1, wherein the ion source and the target chamber together at least partially define one of a plurality of fusion reactors.

10. The mixing reactor of claim 9, wherein the target chamber of each of the plurality of fusion reactors cooperate to substantially surround a cylindrical space.

11. The mixing reactor of claim 10, wherein the activation chamber is substantially annular and is located within the cylindrical space.

12. The hybrid reactor of claim 1, wherein the parent material is low-consistency²³⁵U and the medical isotope is⁹⁹Mo。

13. The hybrid reactor of claim 1, wherein the parent material is uranium or a uranium salt and is in aqueous solution.

14. The hybrid reactor of claim 1, wherein the attenuator is located inside the annular activation chamber and the reflector substantially surrounds the plurality of target chambers.

15. A hybrid reactor for producing medical isotopes, the hybrid reactor comprising:

a fusion portion comprising a long target path disposed within a target chamber substantially surrounding a space, the fusion portion for generating a neutron flux within the target chamber;

a reflector located outside the target chamber and arranged to reflect a portion of the neutron flux towards the space;

an activation chamber located within the space and comprising a parent material that reacts with a portion of the neutron flux to produce a medical isotope during the fission reaction;

an attenuator located within the activation chamber and selected to maintain the fission reaction at a subcritical level; and

16. The hybrid reactor of claim 15, wherein the fusion reactor includes a radio frequency antenna for generating an ion beam from the gas.

17. The hybrid reactor of claim 16, further comprising an accelerator positioned to receive the ion beam and accelerate the ion beam toward a target path, the target path comprising a target material.

18. The hybrid reactor of claim 17, wherein the gas comprises one of deuterium and tritium and the target material comprises the other of deuterium and tritium.

19. The hybrid reactor of claim 15, wherein the target path is substantially linear.

20. The hybrid reactor of claim 19, further comprising at least one magnet positioned to define a magnetic field that collimates the ion beam within at least a portion of the target path.

21. The hybrid reactor of claim 15, wherein the target path is substantially helical.

22. The hybrid reactor of claim 21, further comprising at least one magnet positioned to define a magnetic field that directs the ion beam along a helical target path.

23. The hybrid reactor of claim 15, wherein the parent material is low-consistency²³⁵U and the medical isotope is⁹⁹Mo。

24. The hybrid reactor of claim 15, wherein the parent material is uranium or a uranium salt and is in aqueous solution.

25. The hybrid reactor of claim 15, wherein the fusion reactor is one of a plurality of fusion reactors, each fusion reactor including a target path substantially surrounding a portion of the space.

26. The mixing reactor of claim 25, wherein the activation chamber is substantially annular.

27. The hybrid reactor of claim 26, wherein the attenuator is located inside the annular activation chamber and the reflector substantially surrounds the plurality of target paths.