Remote Sublimation Device

Abstract

A remotely controllable sublimation apparatus (300) including a crucible block (316) adapted to hold a crucible (307) containing a solid mixture including one or more radionuclides, a first heating block (350) with one or more first heating elements (358) configured to selectively generate heat having a first temperature sufficient to at least partially sublimate the solid mixture, and a collection vessel (312) coupled to the first heating block. The crucible block is movable between an open position and a closed position relative to the first heating block. When the crucible block is in the closed position, the one or more first heating elements are configured to heat the crucible block to a first temperature, thereby heating the solid mixture and generating a vapor that is collected by the collection vessel, leaving a solid residue in the crucible consisting essentially of only one or more radionuclides.

Description

[Technical field]

[0001] STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT The United States of America ("US") Government has rights in this invention pursuant to Contract No. DE-AC02-06CH11357 between the US Department of Energy and UChicago Argonne, LLC on behalf of Argonne National Laboratory.

[0002] FIELD OF THE DISCLOSURE This disclosure relates generally to sublimation, and more particularly to a sublimation apparatus that can be remotely controlled. [Background technology]

[0003] Nuclear medicine is a medical specialty that involves the use of small radioactive particles, known as radiopharmaceuticals, to diagnose and treat a variety of conditions, including various types of cancer, cardiac conditions (e.g., heart disease), and other disorders. These radiopharmaceuticals rely on a radionuclide as the active pharmaceutical ingredient. One such radionuclide, copper-67, when combined with a pharmaceutical, is effective in targeting and irradiating small tumors associated with, for example, non-Hodgkin's lymphoma and other types of cancer, without damaging surrounding healthy tissue.

[0004] Radionuclides, the active ingredient in radiopharmaceuticals, can be purified and isolated using a number of known methods. One such method, known as sublimation, involves selectively heating a solid mixture containing the desired radionuclide in such a way as to produce a metal vapor separated from a solid residue consisting essentially only of the desired radionuclide using a sublimation apparatus. More specifically, the solid mixture is positioned in a sublimation vessel and selectively heated therein, thereby producing a metal vapor, which is condensed and collected in a collection vessel coupled to the sublimation vessel and subject to vacuum pressure. Condensation and collection of the metal vapor leaves a solid residue consisting essentially only of the radionuclide in the sublimation vessel. The solid residue can then be removed and subjected to further chemical processing (e.g., dissolved in aqueous acid, separated from other trace metals using anion exchange) to fully purify and isolate the desired radionuclide. Meanwhile, the metal vapor solidified on the solid surface of the collection vessel (usually at a lower temperature from where it was sublimated) can be dissolved and recycled or reused as desired.

[0005] 1 and 2 illustrate one embodiment of a known sublimation apparatus 100 that includes a sublimation vessel 104 (containing the sublimated solids) and a collection vessel 108 (where the sublimated material is condensed and solidified). The sublimation vessel 104 takes the form of a plate 112 and a crucible 116 disposed on the plate 112 and containing a solid mixture containing one or more desired radionuclides. In this embodiment, the solid mixture is an isotopically enriched metal target containing zinc-68 (the target material) and copper-67, which is the desired radionuclide. The collection vessel 108 is mounted above the sublimation vessel 104 and includes a cylinder 120 and a plate 124 coupled to the cylinder 120. To secure the collection vessel 108 to the sublimation vessel 104 (and vice versa), the collection vessel 108 is positioned so that the cylinder 120 surrounds the crucible 116 and the plate 124 engages the plate 112 (and vice versa), with a gasket located between the plates creating a hermetic seal, then a number of bolts 128 are inserted into openings formed in each of the plates 112 and 124, and a number of nuts 132 are used to create the force needed to secure the number of bolts 128 in place and compress the gasket.

[0006] Once the collection vessel 108 is placed on the sublimation vessel 104, a vacuum is applied to the interior volume of the collection vessel 108 and the crucible 116 is heated to a specific temperature (in this case, about 650° C.) by a heating element (not shown) surrounding the lower portion of the sublimation apparatus 100 (where the crucible 116 is located). The zinc-68, which has a higher vapor pressure than that of copper-67 at this specific temperature, is then selectively and substantially converted to a vapor phase. The zinc-68 is then collected by and condensed within the collection vessel 108, thereby leaving a solid residue in the crucible 116 consisting essentially of only copper-67. Thus, the crucible 116 can be removed and the solid residue further processed to fully purify and isolate the copper-67, while the zinc-68 can be melted and recycled as discussed above.

[0007] While the sublimation apparatus 100 is effective in isolating copper-67 from isotopically enriched metal targets including, for example, zinc-68 and copper-67, it can be difficult to manipulate the components of the sublimation apparatus 100, particularly the bolts 128 and nuts 132, to ensure that the sublimation apparatus 100 has a vacuum-tight seal. For example, 90 inch-pounds of torque are required to properly install each of the bolts 128. The difficulty when working with large amounts of radioactive material is compounded by the fact that manipulation must be performed within a shielded environment (e.g., a hot cell), and manipulation is typically performed with a remote mechanical hand called a manipulator, which is effectively a hand-sized pincer that requires relatively little dexterity. Summary of the Invention

[0008] According to a first aspect, there is provided a sublimation apparatus adapted to be disposed in a shielded environment. The sublimation apparatus is configured to be remotely controlled from outside the shielded environment, the sublimation apparatus including: a crucible block adapted to hold a crucible including a solid mixture including one or more radionuclides; a first heating block including one or more first heating elements configured to selectively generate heat having a first temperature sufficient to at least partially sublimate the solid mixture; and a collection vessel coupled to the first heating block, the crucible block being movable relative to the first heating block between an open position in which the crucible block is spaced apart from the first heating block and the collection vessel and a closed position in which the crucible block is at least partially disposed within the first heating block and the collection vessel is in fluid communication with the crucible, the one or more first heating elements being configured to heat the crucible block to a first temperature when the crucible block is in the closed position, thereby heating the solid mixture and generating a vapor that is collected by the collection vessel and leaving a solid residue in the crucible consisting essentially of only the one or more radionuclides.

[0009] According to a second aspect, there is provided a sublimation apparatus adapted to be disposed in a shielded environment, the sublimation apparatus being configured to be remotely controlled from outside the shielded environment, the sublimation apparatus comprising: a crucible block adapted to hold a crucible containing a solid mixture including one or more radionuclides, a lower heating block including one or more lower heating elements configured to selectively generate heat having a first temperature sufficient to at least partially sublimate the solid mixture, an upper heating block thermally insulated from the lower heating block, and a collection vessel coupled to the upper heating block, the crucible block being configured to be insulated from the lower heating block and the collection vessel relative to the lower heating block. the crucible block is movable between an open position in which the crucible block is spaced from the vessel and a closed position in which the crucible block is at least partially disposed within the lower heating block and the collection vessel is in fluid communication with the crucible, wherein when the crucible block is in the closed position, the one or more lower heating elements are configured to heat the crucible block to a first temperature, thereby heating the solid mixture and generating vapor that is collected by the collection vessel and leaving a solid residue in the crucible consisting essentially only of the one or more radionuclides, and the upper heating block includes one or more upper heating elements configured to selectively generate heat having a second temperature sufficient to melt the vapor in the collection vessel.

[0010] According to a third aspect, there is provided a sublimation apparatus adapted to be disposed in a shielded environment, the sublimation apparatus being configured to be remotely controlled from outside the shielded environment, the sublimation apparatus comprising: a crucible block adapted to hold a crucible containing a solid mixture including one or more radionuclides, a lower heating block including one or more lower heating elements configured to selectively generate heat having a first temperature sufficient to at least partially sublimate the solid mixture, an upper heating block thermally insulated from the lower heating block, a collection vessel coupled to the upper heating block, the upper heating block including one or more upper heating elements configured to selectively generate heat to heat the collection vessel, and one or more cooling passages formed through the upper heating block, the one or more cooling passages being and one or more cooling passages configured to selectively direct a cooling fluid toward the collection vessel to facilitate condensation of the metal vapor, wherein the crucible block is movable relative to the lower heating block between an open position in which the crucible block is spaced from the lower heating block and the collection vessel and a closed position in which the crucible block is at least partially disposed within the lower heating block and the collection vessel is in fluid communication with the crucible, and when the crucible block is in the closed position, the one or more lower heating elements are configured to heat the crucible block to a first temperature, thereby heating the solid mixture and generating a vapor that is collected by the collection vessel and leaving a solid residue in the crucible consisting essentially of only one or more radioactive nuclides.

[0011] According to a fourth aspect, there is provided a sublimation apparatus adapted to be disposed in a shielded environment, the sublimation apparatus being configured to be remotely controlled from outside the shielded environment, the sublimation apparatus including a crucible block adapted to hold a crucible, a collection vessel containing vapor condensate, and a heating block coupled to the collection vessel and including one or more heating elements configured to selectively generate heat having a temperature sufficient to melt the vapor condensate in the collection vessel, the crucible block being movable relative to the heating block between an open position in which the crucible block is spaced apart from the heating block and the collection vessel, and a closed position in which the collection vessel is in fluid communication with the crucible, the one or more heating elements being configured to heat the heating block surrounding the collection vessel and the crucible block to a first temperature when the crucible block is in the closed position, thereby melting substantially all of the metal vapor in the collection vessel, and the crucible collecting the melted vapor condensate.

[0012] According to any one or more of the aforementioned first, second, third or fourth aspects, the sublimation apparatus may further comprise any one or more of the following preferred features.

[0013] In some forms, the sublimation apparatus further includes a second heating block thermally insulated from the first heating block, the first heating block including one or more first heating elements configured to selectively generate heat having a first temperature, and the second heating block including one or more second heating elements configured to selectively generate heat having a second temperature sufficient to melt the vapor collected by the collection vessel.

[0014] In some forms, when the crucible block is in the closed position, the crucible block is at least partially disposed within the first heating block, and the one or more first heating elements are configured to generate heat having a first temperature to heat the crucible block to the first temperature.

[0015] In some embodiments, a second heat block surrounds an upper portion of the collection vessel.

[0016] In some embodiments, the sublimation apparatus further includes one or more cooling passages formed directly adjacent to the second heating block, the one or more cooling passages configured to selectively direct a cooling fluid toward the collection vessel to facilitate condensation of the metal vapor.

[0017] In some embodiments, the crucible block further includes a sealing element configured to seal the crucible from the ambient environment when the crucible block is in the closed position.

[0018] In some embodiments, the sublimation apparatus further includes a compensator assembly operably coupled to the crucible block, the compensator assembly including one or more springs configured to apply a constant load to the sealing element.

[0019] In some embodiments, the sublimation apparatus further includes a drive assembly operatively coupled to the crucible block to move the crucible block between the open and closed positions.

[0020] In some forms, the drive assembly includes a jackscrew, a jackscrew shaft operably coupled to the jackscrew and to the crucible block, and a drive motor configured to drive the jackscrew to move the jackscrew shaft, thereby moving the crucible block between the open and closed positions.

[0021] In some configurations, the sublimation apparatus further includes a slip clutch disposed between the drive motor and the jackscrew.

[0022] In some embodiments, the sublimation apparatus further includes one or more cooling passages formed through the upper heating block, the one or more cooling passages configured to selectively direct a cooling fluid toward the collection vessel to facilitate condensation of the metal vapor.

[0023] In some embodiments, the sublimation apparatus further includes an air blower fluidly coupled to the one or more cooling passages and configured to direct cooling fluid to the one or more cooling passages.

[0024] In some embodiments, the sublimation apparatus further includes one or more exhaust passages formed between the upper heating block and the lower heating block, the one or more exhaust passages fluidly coupled to the one or more cooling passages to exhaust the cooling fluid.

[0025] In some embodiments, the crucible block further includes a compensator assembly operably coupled to the crucible block, the compensator assembly including one or more springs configured to apply a constant load to the sealing element.

[0026] In some embodiments, the second temperature is substantially equal to the first temperature.

[0027] In some embodiments, the second temperature is different from the first temperature. [Brief description of the drawings]

[0028] Embodiments of the present invention will now be described with reference to the accompanying drawings.

[0029] [Figure 1] 1 illustrates an embodiment of a known sublimation device. [Diagram 2] FIG. 2 illustrates a sublimation vessel of a known sublimation apparatus. [Diagram 3] FIG. 1 is a perspective view of an example of a sublimation apparatus constructed in accordance with the teachings of the present disclosure and disposed in a shielded environment. [Figure 4] Similar to FIG. 3, but with the occluded environment removed for clarity. [Diagram 5] FIG. 4 is a front view of FIG. [Figure 6] FIG. 6 is a perspective view of the heating block of the sublimation apparatus of FIGS. 3-5, with the insulating block removed for clarity. [Figure 7]FIG. 6 is a cross-sectional view of a heating block of the sublimation apparatus of FIGS. 3 to 5. [Figure 8] 6 illustrates the crucible block of the sublimation apparatus of FIGS. 3-5 in an open position. [Figure 9] FIG. 2 is a close-up view of the crucible block in an open position. [Figure 10] 6 illustrates the crucible block of the sublimation apparatus of FIGS. 3-5 in a closed position. [Figure 11] FIG. 2 is a close-up view of the crucible block in a closed position. [Figure 12] FIG. 6 is a perspective view of a compensator assembly of the sublimation apparatus of FIGS. 3-5. [Figure 13] FIG. 13 is a partial cross-sectional view of the compensator assembly of FIG. 12. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] The present disclosure generally relates to a sublimation apparatus that aims to address problems with the known sublimation apparatus 100 described above and other sublimation apparatuses and methods for producing and isolating one or more radionuclides. More specifically, the disclosed sublimation apparatus is configured to purify and isolate one or more radionuclides while being remotely controlled from outside the shielded environment in which the sublimation apparatus is disposed. In other words, the components of the disclosed sublimation apparatus do not need to be manipulated (e.g., to create a vacuum-tight seal) via a manipulator or manually by an operator within the shielded environment to perform the sublimation. Instead, the components of the disclosed sublimation apparatus can be fully remotely controlled by a remotely located controller or by an operator while the operator is disposed outside the shielded environment. Thus, the disclosed sublimation apparatus is easier to use and safer than the known sublimation apparatus. At the same time, the disclosed sublimation apparatus is as effective (if not more effective) as the known sublimation apparatus and, beneficially, allows for quick and easy adjustment of thermal conditions within the sublimation apparatus to optimize the sublimation process.

[0031] 3-13 illustrate one embodiment of a sublimation apparatus 300 constructed in accordance with the teachings of the present disclosure and disposed in a shielded environment 304 (shown only in FIG. 3). In this embodiment, the shielded environment 304 is a hot cell, i.e., a concrete bunker with thick walls that protect the surrounding environment from the radioactive materials used therein, although in other embodiments, the shielded environment can take different forms. The sublimation apparatus 300 generally includes a crucible block 316 configured to receive and hold a crucible 307 containing a solid mixture including one or more radionuclides, a first (or lower) heating block 350 including one or more first heating elements 358 configured to generate heat to selectively heat the crucible 307 as desired, a collection vessel 312 selectively coupled to the crucible block 316, and a second (or upper) heating block 354 including one or more second heating elements 362 configured to generate heat to selectively heat the collection vessel 312 as desired.

[0032] In this embodiment, the solid mixture preferably takes the form of an isotopically enriched metal target comprising zinc-68 and copper-67 (the desired radionuclides), although other solid mixtures may be used as well. Thus, at least in this embodiment, the sublimation apparatus 300 is configured to purify and substantially isolate copper-67 from an isotopically enriched metal target comprising zinc-68 and copper-67, all of which is remotely controlled from outside the shielded environment 304. To this end, the crucible block 316 is movable relative to the lower heating block 350 between an open position, as exemplified in FIGS. 8 and 9, in which the crucible block 316 is spaced apart from the lower heating block 350 and the collection vessel 312, and a closed position, as exemplified in FIGS. 10 and 11, in which the crucible block 316 is at least partially disposed within the lower heating block 350 and the collection vessel 312 is in fluid communication with the crucible 307. If it is desired to substantially sublimate the solid mixture, the crucible block 316 is positioned in a closed position and one or more first heating elements 358 are configured to heat the crucible 307 carried by the crucible block 316 to a first predetermined temperature that heats the solid mixture to produce a solid residue consisting essentially only of vapor (in this case, metallic vapor of zinc-68 that solidifies in the collection vessel 312) and the desired radionuclide (in this case, copper-67) in the crucible 307. In this example, heating the crucible 307 sublimes at least approximately 95% of the metallic zinc-68 in the solid mixture, such that the solid residue initially comprises approximately 5% of the metallic zinc-68 in the solid mixture, with the remaining solid residue being copper-67 and other trace metals. Thus, as used herein, "substantially sublimes" means that at least about 95% of the metallic material or materials to be sublimated is actually sublimated. On the other hand, when it is desired to substantially melt the sublimated components, the crucible block 316 is positioned in a closed position and one or more second heating elements 362 are configured to heat at least a portion of the collection vessel 312 to a second predetermined temperature that substantially melts the metal vapor and returns the liquefied metal to the crucible 307. Similarly, as used herein, "substantially melt" means that at least approximately 95% of the sublimated components that are melted are actually liquefied.

[0033] The crucible block 316 is generally configured to receive the crucible 307 and retain the crucible 307 as the crucible block 316 moves between open and closed positions. As best illustrated in Figures 6 and 7, the crucible block 316 is at least partially, if not completely, surrounded by an insulating block 318 such that the crucible block 316 is thermally insulated from the surrounding environment. As best illustrated in Figures 8-11, the crucible block 316 in this embodiment takes the form of an integral flange portion specifically configured to receive and retain the crucible 307 in this manner. To this end, the integral flange portion 316 has a peripheral wall 320 and a cavity 324 defined by the peripheral wall 320. The cavity 324 is sized to receive a portion of the crucible 307 therein, and the peripheral wall 320 is in turn configured to retain the crucible 307 in the cavity 324.

[0034] In this embodiment, the first heating block 350 and the second heating block 354 each define two heating zones that can operate independently of each other. One or more lower heating elements 358 introduced upwards are configured to selectively generate heat having a first predetermined temperature, which is sufficient to at least partially sublimate the solid mixture in the crucible 307. In some embodiments, for example, when the solid mixture is an isotopically enriched metal target including zinc-68 and copper-67, the first predetermined temperature is equal to about 650°C to 700°C, which is sufficient to substantially sublimate the zinc-68 in the solid mixture. However, in other embodiments, the first predetermined temperature can be less than 650°C (e.g., about 200°C or about 450°C), depending on the internal pressure. Similarly, one or more upper heating elements 362 introduced upwards are configured to selectively generate heat having a second predetermined temperature, which is sufficient to liquefy or melt the metal collected in 312. In some embodiments, the second predetermined temperature is equal to or substantially equal to the first predetermined temperature (e.g., between about 650° C. and 700° C.), while in other embodiments, the second predetermined temperature can be lower than the first predetermined temperature.

[0035] In this embodiment, the lower heating block 350 includes four lower heating elements 358 and the upper heating block 354 also includes four upper heating elements 362, although the exact number of lower heating elements 358 and upper heating elements 362 may vary. Each of the lower heating elements 358 and upper heating elements 362 preferably takes the form of a cartridge heater (e.g., having a rated power of 125 W) disposed in a pocket 364 formed in the lower heating block 350 or upper heating block 354, with the lower cartridge heater 358 being oriented generally horizontally (i.e., perpendicular to the longitudinal axis 366 of the sublimation apparatus 300) and the upper heating cartridge 362 being oriented generally vertically (i.e., parallel to the longitudinal axis 366). However, in other embodiments, the lower heating cartridges and / or upper heating cartridges may be arranged in a different manner and / or different heating elements may be used. For example, a heat pump, heat pipes, or electrical resistance wire may be used in place of the heating cartridges.

[0036] Thus, in this embodiment, the lower heating block 350 defines a first (or lower) heating zone configured to heat a first (or lower) portion of the sublimation apparatus 300 to a first predetermined temperature, and the upper heating block 354 defines a second (or upper) heating zone that is thermally insulated from the first heating zone and configured to heat a second (or upper) portion of the sublimation apparatus 300 to a second predetermined temperature. The second heating zone is generally insulated from the first heating zone (and vice versa) via a number of insulating blocks (e.g., made of marinite). In this embodiment, the number of insulating blocks includes four identical solid insulating blocks 368A surrounding the upper heating block 354 (and, more specifically, one or more upper heating elements 362), a partially open insulating block 368B surrounding the upper heating block 354, and a solid insulating block 368C surrounding the lower heating block 350. Preferably, the partially open block 368B is disposed between two adjacent solid insulating blocks 368A, as discussed in more detail below, although in some embodiments the partially open block 368B may be disposed between one of the solid insulating blocks 368A and the solid insulating block 368C. In any case, because the first and second heating zones are thermally insulated from one another, the first and second portions of the sublimation apparatus 300 may be heated to different temperatures at different times. For example, the first portion of the sublimation apparatus 300 may be heated (e.g., to a first temperature) while the second portion of the sublimation apparatus 300 is not heated (or is cooled). Similarly, the second portion of the sublimation apparatus 300 may be heated (e.g., to a second temperature) while the first portion of the sublimation apparatus 300 is not heated. If desired, the first and second zones may also be heated simultaneously (to the same temperature or different temperatures).

[0037] The collection vessel 312 is generally configured to collect metal vapor generated when the lower heating block 350 heats the solid mixture to a first predetermined temperature. As best illustrated in Figures 6 and 7, in this embodiment, the collection vessel 312 takes the form of a telescopic tube made of alumina (but can be made of another ceramic material or graphite) and has a first cylindrical portion 370 disposed in a second cylindrical portion 374 such that the first cylindrical portion 370 and the second cylindrical portion 374 are slidable relative to one another. The collection vessel 312 also includes a baffle 376 carried by the first cylindrical portion 370 and includes a plurality of holes that fluidly couple the first cylindrical portion 370 and the second cylindrical portion 374 (albeit to a limited extent due to the size of the holes). In this embodiment, the baffle 376 is located approximately halfway between the bottom end of the first cylindrical portion 370 and the top end of the second cylindrical portion 374, such that the baffle 376 is located approximately in the center of the upper heating block 354. However, in other embodiments, the baffle 376 can be located closer to the top end of the second cylindrical portion 374. For example, the baffle 376 can instead be located directly adjacent to the top end of the second cylindrical portion 374.

[0038] 6 and 7, the collection vessel 312 is disposed within a central opening 378 of the lower heating block 350 and a central opening 382 of the upper heating block 354 that is coaxial with the central opening 378, both extending along a longitudinal axis 366. The lower heating block 350 surrounds lower portions of both the first cylindrical portion 370 and the second cylindrical portion 374, as well as a portion of the crucible block 316 (when the crucible block 316 is in the closed position). Thus, when the lower heating element 358 generates heat, the lower heating element 358 is configured to heat at least lower portions of both the first cylindrical portion 370 and the second cylindrical portion 374, as well as the crucible block 316 (when the crucible block 316 is in the closed position), as discussed in more detail below. Meanwhile, the upper heating block 354 surrounds an upper portion of the first cylindrical portion 370 and at least a middle portion of the second cylindrical portion 374. Thus, when the upper heating element 362 generates heat, the upper heating element 362 is configured to heat at least an upper portion of the first cylindrical portion 370 and a middle portion of the second cylindrical portion 374, as will be discussed in more detail below.

[0039] Preferably, the sublimation apparatus 300 also includes means for selectively and controllably cooling the second heating zone (and more specifically, the upper portion of the first cylindrical portion 370), for example, to facilitate or accelerate the sublimation process when the first heating zone is heating the first (or lower) portion of the sublimation apparatus 300 to a first predetermined temperature. To this end, the means for selectively cooling the second heating zone can cool the second heating zone to one or more temperatures below the first predetermined temperature. In some embodiments, the means for selectively cooling the second heating zone can cool the second heating zone to a number of different temperatures that decrease as the second heating zone moves away from the lower heating block 350. For example, the means for selectively cooling the second heating zone can cool the second heating zone to four different temperatures, for example, below 30° C., below 50° C., below 70° C., and below 120° C., as the second heating zone moves away from the lower heating block 350. In any event, it will be appreciated that the temperature can be adjusted as necessary to control the sublimation process and the location within the collection vessel where the vapor condenses.

[0040] The sublimation apparatus 300 of this embodiment includes such means in the form of one or more cooling passages 400, an air blower 404, and one or more exhaust passages 408. Preferably, the sublimation apparatus 300 includes four cooling passages 400 generally disposed around the upper heating block 354 (see FIG. 6), although in other embodiments, the sublimation apparatus 300 may include more or fewer cooling passages 400. The one or more cooling passages 400 are defined between the upper heating block 354 and the insulating block 368 such that the one or more cooling passages 400 are directly adjacent to and thermally coupled to the upper heating block 354. The one or more cooling passages 400 then extend generally in a direction along the longitudinal axis 366. Meanwhile, the air blower 404 is fluidly coupled to the one or more cooling passages 400 and configured to selectively direct a cooling fluid, e.g., air or water from a cooling fluid source (not shown), to the sublimation apparatus 300 and the one or more cooling passages 400, thereby cooling the upper heating block 354 (as well as the upper portion of the first cylindrical portion 370). In this embodiment, the air blower 404 extends partially outwardly through the insulating block 368 at a location directly adjacent to the upper portion of the second cylindrical portion 374. Preferably, the sublimation apparatus 300 includes four exhaust passages 408 (see FIG. 6), although in other embodiments, the sublimation apparatus 300 may include more or fewer exhaust passages 408. The one or more exhaust passages 408 are fluidly coupled to the one or more cooling passages 400 to exhaust any cooling fluid provided to and flowing through the one or more cooling passages 400 (via the air blower 404). In this embodiment, one or more exhaust passages 408 are defined between the partially open insulating block 368B and the bottom solid insulating block 368A such that the one or more exhaust passages 408 are positioned upstream of the lower heating element 358. In this manner, any cooling fluid exhausted from the cooling passages 400 (and any heat subsequently drawn from the upper heating block 354) does not affect the temperature of the lower heating block 350 (or first heating zone).

[0041] As best illustrated in Figures 9 and 11, the sublimation apparatus 300 of this embodiment also includes a sealing element 500. The sealing element 500 is generally configured to seal the crucible 307 from within the lower heating block 350 and from the surrounding environment when the crucible block 316 is in the closed position. In this embodiment, the sealing element 500 takes the form of a grafoil gasket (e.g., a high purity grafoil gasket or a reactor grade grafoil gasket) that can withstand higher temperatures, such as the first predetermined temperature described herein, to partially sublimate the solid mixture contained in the crucible 307. However, in other embodiments, the sealing element 500 can instead take the form of a C-seal or other type of sealing element and / or can instead be made of aluminum or gold, for example. In any case, the sealing element 500 is carried by the crucible block 316 such that the sealing element 500 surrounds the peripheral wall 320 of the integral flange portion 316. Thus, when the crucible block 316 is in the closed position, the sealing element 500 sealingly engages with a bottom portion of the lower heating block 350 to prevent any material (or heat) (e.g., between the crucible block 316 and the lower heating block 350) from escaping the sublimation apparatus 300. As best illustrated in FIG. 11, the sealing engagement is enhanced by the fact that when the crucible block 316 is in the closed position, the sealing element 500 is sandwiched between first and second opposing protrusions 502 and 503 formed on the lower heating block 350 and the crucible block 316, respectively. In other embodiments, for example, when the sealing element 500 takes the form of a C-seal or other type of sealing element, the sealing element 500 may be disposed in a groove that helps to sandwich the sealing element 500 in a desired position.

[0042] 9 and 11, the sublimation apparatus 300 of this embodiment further includes a collar 504 and a spacer 508. The collar 504 is disposed in the collection vessel 312 (more specifically, matingly engaged with the first cylindrical portion 370) and acts as a barrier to prevent chemical reactions between the metal being sublimated (zinc-68 in this case) and the material of the lower heating block 350 (stainless steel in this case), which could damage components of the sublimation apparatus 300 and cause loss of the sublimated material. In this embodiment, the collar 504 matingly engages with a bottom portion of the first cylindrical portion 370 such that the collar 504 is fixedly disposed within the collection vessel 312. However, in other embodiments, the collar 504 can instead be movably disposed within the collection vessel 312 such that the collar 504 occupies a first position when the crucible block 316 is in the open position and the collar 504 occupies a second position when the crucible block 316 is in the closed position. Meanwhile, the spacer 508 is sized and positioned to help maintain the sealing element 500 in a desired position relative to the integral flange portion 316. In this embodiment, the spacer 508 matingly engages the collar 504 such that the spacer 508 is fixedly disposed between the sealing element 500 and the collar 504. The spacer 508 is then surrounded by the lower heating block 350, and the spacer 508 surrounds the peripheral wall 320 of the integral flange portion 316 (and, in turn, the crucible 307) when the crucible block 316 is in the closed position, as illustrated in FIG.

[0043] Optionally, the sublimation apparatus 300 of this embodiment further includes a funnel 512 coupled to the crucible 307 to help direct the sublimated (condensed metal vapor collected in the collection vessel 312) molten metal back to the crucible 307 (or to a new crucible 307) when desired. In this embodiment, the funnel 512 is coupled to the crucible 307 such that the funnel 512 receives and surrounds a portion of the peripheral wall 320. The funnel 512 is then movable with the crucible 307 (and the crucible block 316) relative to the collar 504 and the spacer 508 as the crucible block 316 is moved between the open and closed positions. The spacer 508 helps guide the funnel 512 (and the crucible 307) to the proper position as the crucible block 316 moves toward and into the open position. When the crucible block 316 reaches and is in the closed position shown in Figures 10 and 11, the funnel 512 is disposed within the collection vessel 312 and engages both the collar 504 and the spacer 508 such that the funnel 512 is disposed substantially between the collar 504 and the spacer 508. Conversely, when the crucible block 316 is in the open position shown in Figures 8 and 9, the funnel 512 is also disposed outside of the collection vessel 312 such that the funnel 512 is spaced apart from both the collar 504 and the spacer 508.

[0044] 12 and 13, the sublimation apparatus 300 of this embodiment further includes a compensator assembly 600 operably coupled to the crucible block 316. The compensator assembly 600 is generally configured to maintain a relatively constant load on the sealing element 500 to compensate for thermal expansion and sealing creep conditions during operation of the sublimation apparatus 300. In this embodiment, the compensator assembly 600 includes a plurality of compensator housing plates 608, two pairs of compensator springs 612, and upper and lower spring plates 616 and 620 for holding the compensator springs 612. The compensator housing plates 608 are coupled (e.g., bolted) together to form a housing for the springs 612. The compensator springs 612 are disposed within the housing such that the compensator springs 612 of each pair are concentrically arranged and one end of each compensator spring 612 is fixedly coupled to an upper spring plate 616 that is fixedly coupled to the housing. However, as best illustrated in Figures 12 and 13, the other end of each compensator spring 612 extends through a respective opening formed through a lower spring plate 616 that is movable within the housing to adjust the total load (i.e., spring force) generated by the pair of compensator springs 612.

[0045] The compensator assembly 600 of this embodiment also includes a shaft plate 624 and a pair of spring shafts 628 extending between and connecting a bottom one of the compensator housing plates 608 and the shaft plate 624. Each of the spring shafts 628 extends in a direction parallel to the longitudinal axis 366. As illustrated in FIGS. 12 and 13 , each of the spring shafts 628 is at least partially surrounded by a respective one of the pairs of compensator springs 612. Thus, the total load generated by the two pairs of compensator springs 612 is then transferred to the pair of spring shafts 624, which in turn transfer the total load to the shaft plate 624.

[0046] 4, 5, 8, and 10, the sublimation apparatus 300 of this embodiment also includes a plurality of compensator shafts 650 and a drive assembly 654. The plurality of compensator shafts 650 are generally configured to operatively couple the compensator assembly 600 to the crucible block 316. As best illustrated in these figures, the plurality of compensator shafts 650 are arranged such that a first end 658 of each shaft 650 is disposed in and secured to the lower heating block 350 and a second end 662 of each shaft 650 extends through and is secured to the shaft plate 624. With the multiple compensator shafts 650 fixed in this manner, the total load generated by the two pairs of compensator springs 612 and transmitted to the shaft plate 624 is similarly transmitted to the compensator shaft 650, which in turn applies a first force to the sealing element 500 in a first direction (in this case downward) away from the lower heating block 350. Each of the compensator shafts 650 extends in a direction parallel to the longitudinal axis 366 such that the crucible block 316 is movable along the multiple compensator shafts 650 (through openings formed in the crucible block 316) as the crucible block 316 moves between the open and closed positions.

[0047] Similar to the plurality of compensator shafts 650, a drive assembly 654 is also operatively coupled to the crucible block 316 for driving movement of the crucible block 316 along the plurality of compensator shafts 650 between open and closed positions. In this embodiment, the drive assembly 654 takes the form of a jack assembly including a jack tube 700, a jack plate 704, a jack shaft 708, an extension tube 712, and a screw jack 716, along with a drive motor 720 configured to drive the components of the jack assembly to achieve the desired movement of the crucible block 316. Additionally, the drive assembly 654 is configured to generate a second force applied to the sealing element 500 (via the jack tube 700) in a second direction (in this case upward) toward the lower heating block 350.

[0048] 4, 5, 8, and 9, the jack tube 700 is fixedly coupled to the crucible block 316 such that the jack tube 700 and the crucible block 316 move together along the longitudinal axis 366. More specifically, the jack tube 700 has a first end 720 that is fixedly coupled to a bottom surface of the integral flange portion 316. The jack tube 700 also has a second end 724 that is fixedly coupled to the jack plate 704 such that the jack tube 700 and the jack plate 704 also move together along the longitudinal axis 366. Although somewhat difficult to see, best seen in FIGS. 8 and 10, the jack plate 704 has a pair of shaft openings 728 that are sized to receive the pair of compensator shafts 650 that each extend through the pair of shaft openings 728.

[0049] The jack shaft 708 is fixedly coupled to the jack plate 704 such that the jack shaft 708 moves in unison with the jack plate 704 (and the jack tube 700 and the crucible block 316). More specifically, the jack shaft 708 has a first end that is fixedly coupled to a surface of the jack plate 704 opposite the second end 724 of the jack tube 700. Meanwhile, the jack shaft 708 has a second end that is movably (e.g., slidably) disposed within the extension tube 712, which is fixed in place (e.g., by the upper spring plate 616). Thus, the crucible block 316, the jack tube 700, the jack plate 704, and the jack shaft 708 can all be moved relative to the extension tube 712 by moving the second end of the jack shaft 708 further inward or further outward of the extension tube 712 along the longitudinal axis 366.

[0050] The jackscrew 716 is operably coupled to a portion of the jack shaft 708 in a known manner to control the position of the second end of the jack shaft 708 (and the crucible block 316) relative to the extension tube 712. Similarly, the drive motor 720 is operably coupled to the jackscrew 716 to control the position of the jackscrew 716 and, in turn, the second end of the jack shaft 708 relative to the extension tube 712. In this embodiment, the drive motor 720 is a direct current (DC) motor with a variable speed controller. However, in other embodiments, the drive motor 720 can be an alternating current motor. Additionally, in this embodiment, there is a large gear ratio from the drive motor 720 to the jack shaft 708 to prevent overloading by the jack assembly. Optionally, in this embodiment, the drive assembly 654 also includes a slip clutch disposed between the jackscrew 716 and the drive motor 720. The slip clutch helps control the torque between the jackscrew 716 and the drive motor 720 to further prevent overloading the jack assembly.

[0051] In some embodiments, such as the embodiment illustrated in Figures 3-13, the sublimation apparatus 300 includes a support structure 750 configured to hold and support the components of the sublimation apparatus 300. As best illustrated in Figures 4 and 5, the support structure 750 in this embodiment takes the form of a table having a number of legs 754, a first support 758 coupled to the number of legs 754, and a second support 762 coupled to the number of legs 754. As best illustrated in Figures 4 and 5, the compensator assembly 600 is generally disposed between the first support 758 and the second support 762. More specifically, a bottom housing plate 608 of the plurality of compensator housing plates 608 is directly coupled (e.g., bolted) to a first support 758, a top housing plate 608 of the plurality of compensator housing plates 608 is directly coupled (e.g., bolted) to a second support 762, and the remaining compensator housing plate 608, the pair of compensator springs 612, and the upper spring plate 616 and the lower spring plate 620 are disposed between the first support 758 and the second support 762. However, the second support 762 includes a pair of openings through which the pair of spring shafts 628 extend, respectively, such that the shaft plate 624 is disposed above the second support 762 and the pair of spring shafts 628 are partially disposed above the second support 762. On the other hand, the drive assembly 654 is generally coupled to and disposed above the second support 762. More specifically, the screw jack 716 and the drive motor 720 are directly coupled to the second support 762, the jack tube 700 and the jack plate 704 are disposed above the second support 762, and the jack shaft 708 and the extension tube 712 are disposed partially above the second support 762.

[0052] As discussed above, sublimation apparatus 300 is configured to purify and isolate one or more radionuclides (in this example, copper-67) while being remotely controlled from outside of shielded environment 304. To this end, sublimation apparatus 300 includes a local control system 800 communicatively connected (via a wired or wireless connection) to sublimation apparatus 300 to control operation of sublimation apparatus 300. More specifically, local control system 800 is configured to control the temperature and heating rate within sublimation apparatus 300 by controlling lower heating element 358, upper heating element 362, air blower 404, drive assembly 654, and other components (e.g., sensors, switches) of sublimation apparatus 300.

[0053] In this example, the local control system 800 includes a local controller 804, a number of sensors communicatively connected to the local controller 804, and a number of valves (e.g., a number of solenoid valves) communicatively connected to the local controller 804 to open, close, or otherwise regulate components of the sublimation apparatus 300. The local controller 804, preferably a J-KEM controller, is communicatively connected to the lower heating element 358, the upper heating element 362, the air blower 404, the drive motor 720, the number of sensors, and the number of valves such that the local controller 804 can control the operation of the sublimation apparatus 300. The local controller 804 can then be communicatively connected (via a wired or wireless connection) to a remotely located controller (e.g., a central controller located outside the shielded environment 304) and can be automatically controlled by the remotely located controller (e.g., a central controller located outside the shielded environment 304) or can be manually controlled by an operator located outside the shielded environment 304.

[0054] Sensors are generally coupled to components of the sublimation apparatus 300 to sense pressure, temperature, force, and other variables within the sublimation apparatus 300. In this embodiment, the sensors include load cells, thermocouples, and a pressure gauge to measure pressure within the collection vessel 312. Although not illustrated herein, the load cells are distributed throughout the compensator assembly 600 to detect the total load generated by the compensator assembly 600. Also not illustrated herein, thermocouples are disposed in the lower heating block 350 and the upper heating block 354 to detect the temperature and heating rate of the lower heating block 350 and the upper heating block 354, respectively. However, in other embodiments, the sensors may include different and / or additional sensors. In any case, the local controller 804 may collect data from the sensors employed in the sublimation apparatus 300 to ensure that the sublimation and dissolution process is being performed properly and for use in controlling the sublimation apparatus 300. For example, local controller 804 can use temperature data from thermocouples in lower heating block 350 and upper heating block 354 to adjust the temperature of heat generated by lower heating element 350 and upper heating element 354. The plurality of valves, also not illustrated herein, can include one or more valves for opening and closing collection vessel 312 to vacuum pressure or inert gas, as well as one or more valves for controlling jack screw 716, depending on the desired operation of sublimation apparatus 300. However, in other embodiments, the plurality of valves can include different and / or additional valves.

[0055] When it is desired to operate the sublimation apparatus 300 to purify and substantially isolate copper-67 (or other radiopharmaceutical) from the isotopically enriched metal target, including zinc-68 and copper-67 (or other metal target), contained in the crucible 307, the local controller 804 (in response to a request from a remotely located controller or a remotely located operator) generally moves the crucible block 316, including the crucible 307, from an open position to a closed position. The local controller 804 does this by actuating the drive motor 720, which drives the rotation of the jack screw 716 in a first direction (e.g., a clockwise direction) to move the jack shaft 708 upward from the position shown in Figures 8 and 9 to the position shown in Figures 10 and 11. The jack tube 700 and jack plate 704 move in unison with the jack shaft 708, thereby simultaneously moving the jack tube 700 and jack plate 704 upward from the position shown in Figures 8 and 9 to the position shown in Figures 10 and 11. The crucible block 316 also moves in unison with the jack tube 700, thereby simultaneously moving the crucible block 316 upward from the position shown in Figures 8 and 9 until the crucible block 316 reaches its closed position, as shown in Figures 10 and 11. As discussed above, when the crucible block 316 is in the closed position, the crucible block 316 is at least partially disposed within the lower heating block 350. More specifically, the integral flange portion 316 is disposed partially within the lower heating block 350 such that the lower heating element 358 is positioned directly adjacent to and substantially surrounding the crucible 307 carried by the integral flange portion 316. At the same time, the sealing element 500 sealingly engages with the bottom portion of the lower heating block 350 and the collection vessel 312 is in fluid communication with the crucible 307, thereby creating a sealed process chamber within the collection vessel 312 and sealing the crucible 307 from the ambient environment. The first and second forces, generated and applied by the compensator shaft 650 and the drive assembly 654, respectively, also help maintain this sealed process chamber as the sealing element 500 sealingly engages with the bottom portion of the lower heating block 350.Further, although not illustrated, it will be understood that at some point before the sublimation process begins, the collection vessel 312 is exposed to a dynamic or static vacuum by coupling a vacuum source to the second cylindrical portion 374 of the collection vessel 312.

[0056] The local controller 804 then activates the lower heating element 358, causing the lower heating element 358 to generate heat having a first temperature that heats the lower portion of the sublimation apparatus 300, particularly the integral flange portion 316 and the crucible 307, to a first predetermined temperature (monitored by a plurality of thermocouples). When the solid mixture contained in the crucible 307 is heated to the first predetermined temperature, substantially all (i.e., at least about 95%) of the zinc-68 in the solid mixture is converted to metal vapor that is collected by the collection vessel 312 and condensed within the collection vessel 312, particularly within an upper portion of the first cylindrical portion 370 of the collection vessel 312. The conversion of the zinc-68 to metal vapor leaves the crucible 307 with a solid residue consisting essentially only of copper-67 (copper-67 has a lower vapor pressure than zinc-68 at the first temperature and therefore is not converted to vapor).

[0057] Generally speaking, while the lower heating element 358 is generating heat having a first temperature that sublimes substantially all of the zinc-68, the local controller 804 keeps the upper heating element 362 off so that it does not provide any heat to the second heating zone. In some cases, it may be necessary to actually lower the temperature of the second heating zone to facilitate or accelerate the sublimation of the zinc-68. In these and other cases, the local controller 804 activates a means for selectively cooling the second heating zone. More specifically, the local controller 804 causes the air blower 404 to draw in a cooling fluid that is then routed through one or more cooling passages 400, thereby cooling the upper heating block 354 as well as the top portion of the first cylindrical portion 370. The cooling fluid is then pumped out of the second heating zone (and the sublimation device 300) via one or more exhaust passages 408.

[0058] Once the sublimation process is complete (i.e., substantially all of the zinc-68 has been sublimated, which in some cases may take a minimum of 100 minutes, but in other cases may take 200-230 minutes), the local controller 804 opens one or more valves to return the collection vessel 312 to ambient pressure, and then generally moves the crucible block 316 back from the closed position to the open position. The local controller 804 does this by again actuating the drive motor 720, but this time driving the rotation of the jack screw 716 in a second direction (e.g., counterclockwise), which causes the jack shaft 708 to move downwardly from the position shown in Figures 10 and 11 to the position shown in Figures 8 and 9. Moving the jack shaft 708 in this manner causes the jack plate 704, jack tube 700, and crucible block 316 to simultaneously move downwardly from the positions shown in Figures 10 and 11 to the positions shown in Figures 8 and 9. As discussed above, when the crucible block 316 is in the open position, the crucible block 316 is spaced from the lower heating block 350 and the collection vessel 312. Similarly, the jack tube 700 and jack plate 704 are spaced from the lower heating block 350 and the collection vessel 312, with the jack plate 704 located approximately midway between the lower heating block 350 and the shaft plate 624.

[0059] Once the crucible block 316 has returned to the open position, the crucible 307 can be removed (e.g., via a manipulator or other robotic means as described above) and the solid residue contained therein can be subjected to further processing to fully purify and isolate the copper-67. At the same time, if desired, the sublimation apparatus 300 can be operated to melt the zinc-68 condensed in the collection vessel 312 (more specifically, solidified on the inner sidewall of the first cylindrical portion 370) and collect the melted zinc-68 in a new crucible 307 placed on the crucible block 316. To this end, the local controller 804 again causes the crucible block 316 containing the new crucible 307 to return from the open position to the closed position as described above. The local controller 804 activates the upper heating element 362, causing the upper heating element 362 to generate heat having a second predetermined temperature that heats the upper portion of the sublimation apparatus 300, particularly the upper portion of the first cylindrical portion 370 and the middle portion of the second cylindrical portion 374, to a second predetermined temperature. The local controller 804 may also activate the lower heating element 358, causing the lower heating element 358 to generate heat having a first predetermined temperature sufficient to help melt at least the zinc-68 and that heats the lower portion of the sublimation apparatus 300, particularly the lower heating block 350, to a first predetermined temperature (which may be the same as or different from the second predetermined temperature). At some point before this occurs, the collection vessel 312 (particularly the second cylindrical portion 374) is filled with an inert gas, such as argon, helium, nitrogen (or any combination of these gases), or any combination of these gases mixed with hydrogen. The condensed zinc-68 in the collection vessel 312 is then heated, thereby converting substantially all of the zinc-68 from a solid to a liquid. The liquefied zinc-68 then falls into the collection vessel 312 and is directed by the collar 504 and funnel 512 into the new crucible 307. The liquefied zinc-68 collected by the new crucible 307 can then be solidified by allowing the system to return to ambient temperature and can then be recycled or reused in further production of radionuclides and further sublimation processes.

[0060] It will be understood that the sublimation and dissolution process described herein can be repeated any number of times with any number of different crucibles and different solid mixtures. It will also be recognized that the sublimation apparatus 300 can include numerous other components not specifically illustrated herein. In some embodiments, the sublimation apparatus 300 can include a fan to help maintain the compensator assembly 600 at ambient temperature.

[0061] The following list of aspects reflects various embodiments expressly contemplated by the present application. Those of ordinary skill in the art will readily appreciate that the following aspects are not intended to be limiting of the embodiments disclosed herein, nor are they exhaustive of all embodiments contemplated in light of the above disclosure, but instead are meant to be exemplary in nature.

[0062] Aspect 1. A sublimation apparatus adapted to be disposed in a shielded environment and configured to be remotely controlled from outside the shielded environment, the sublimation apparatus comprising: a crucible block adapted to hold a crucible containing a solid mixture including one or more radionuclides; a first heating block comprising one or more first heating elements configured to selectively generate heat having a first temperature sufficient to at least partially sublimate the solid mixture; and a collection vessel coupled to the first heating block, the crucible block being adapted to selectively generate heat having a first temperature sufficient to at least partially sublimate the solid mixture. and a sublimation apparatus movable between an open position in which the crucible block is spaced from the first heating block and the collection vessel and a closed position in which the crucible block is at least partially disposed within the first heating block and the collection vessel is in fluid communication with the crucible, and when the crucible block is in the closed position, one or more first heating elements are configured to heat the crucible block to a first temperature, thereby heating the solid mixture and generating a vapor that is collected by the collection vessel and leaving a solid residue in the crucible consisting essentially of one or more radionuclides.

[0063] Aspect 2. The sublimation apparatus of aspect 1, further comprising a second heating block thermally insulated from the first heating block, the first heating block comprising one or more first heating elements configured to selectively generate heat having a first temperature, and the second heating block comprising one or more second heating elements configured to selectively generate heat having a second temperature sufficient to dissolve the vapor condensate collected by the collection vessel.

[0064] Aspect 3. The sublimation apparatus of claim 2, wherein when the crucible block is in the closed position, the crucible block is at least partially disposed within the first heating block, and the one or more first heating elements are configured to generate heat having a first temperature to heat the crucible block to the first temperature.

[0065] Aspect 4. The sublimation apparatus of aspect 2 or 3, wherein a second heating block surrounds an upper portion of the collection vessel.

[0066] Embodiment 5. A sublimation apparatus as described in any one of embodiments 1 to 4, further comprising one or more cooling passages formed directly adjacent to the second heating block, the one or more cooling passages configured to selectively direct cooling fluid toward the collection vessel to facilitate condensation of the metal vapor.

[0067] Embodiment 6. The sublimation apparatus of any one of embodiments 1-5, wherein the crucible block further comprises a sealing element configured to seal the crucible from an ambient environment when the crucible block is in the closed position.

[0068] Embodiment 7. The sublimation apparatus of embodiment 6, further comprising a compensator assembly operably coupled to the crucible block, the compensator assembly comprising one or more springs configured to apply a constant load to the sealing element.

[0069] Aspect 8. The sublimation apparatus of aspect 7, further comprising a plurality of compensator shafts coupled to the first heating block and to the compensator assembly, wherein the crucible block is movable between an open position and a closed position relative to the first heating block via the plurality of compensator shafts.

[0070] Embodiment 9. The sublimation apparatus of any one of embodiments 1-8, further comprising a drive assembly operatively coupled to the crucible block to move the crucible block between the open and closed positions.

[0071] Aspect 10. The sublimation apparatus of aspect 9, wherein the drive assembly comprises a screw jack, a screw jack shaft operably coupled to the screw jack and to the crucible block, and a drive motor configured to drive the screw jack to move the screw jack shaft, thereby moving the crucible block between the open and closed positions.

[0072] Aspect 11. The sublimation apparatus of aspect 10, further comprising a slip clutch disposed between the drive motor and the screw jack.

[0073] Aspect 12. A sublimation apparatus adapted to be disposed in a shielded environment and configured to be remotely controlled from outside the shielded environment, the sublimation apparatus comprising: a crucible block adapted to hold a crucible containing a solid mixture including one or more radionuclides; a lower heating block, the lower heating block comprising one or more lower heating elements configured to selectively generate heat having a first temperature sufficient to at least partially sublimate the solid mixture; an upper heating block thermally insulated from the lower heating block; and a collection vessel coupled to the upper heating block, the crucible block being adapted to be insulated from the lower heating block relative to the lower heating block. and a lower heating block configured to selectively generate heat having a second temperature sufficient to melt the vapor in the collection vessel, the upper heating block being ...

[0074] Aspect 13. The sublimation apparatus of aspect 12, further comprising one or more cooling passages formed through the upper heating block, the one or more cooling passages configured to selectively direct cooling fluid toward the collection vessel to facilitate condensation of the metal vapor.

[0075] Aspect 14. The sublimation apparatus of aspect 13, further comprising an air blower fluidly coupled to the one or more cooling passages and configured to direct cooling fluid to the one or more cooling passages.

[0076] Aspect 15. A sublimation apparatus as described in aspect 13 or 14, further comprising one or more exhaust passages formed between the upper heating block and the lower heating block, the one or more exhaust passages being fluidly coupled to the one or more cooling passages to discharge a cooling fluid.

[0077] Embodiment 16. The sublimation apparatus of any one of embodiments 12-15, wherein the crucible block further comprises a sealing element configured to seal the crucible from an ambient environment when the crucible block is in the closed position.

[0078] Aspect 17. The sublimation apparatus of aspect 16, further comprising a compensator assembly operably coupled to the crucible block, the compensator assembly comprising one or more springs configured to apply a constant load to the sealing element.

[0079] Aspect 18. A sublimation apparatus as described in aspect 17, further comprising a plurality of compensator shafts coupled to the heating block and to the compensator assembly, wherein the crucible block is movable between an open position and a closed position relative to the heating block via the plurality of compensator shafts.

[0080] Aspect 19. The sublimation apparatus of aspect 12, further comprising a drive assembly operably coupled to the crucible block to move the crucible block between the open and closed positions.

[0081] Aspect 20. The sublimation apparatus of aspect 12, wherein the second temperature is substantially equal to the first temperature.

[0082] Aspect 21. A sublimation apparatus adapted to be disposed in a shielded environment and configured to be remotely controlled from outside the shielded environment, the sublimation apparatus comprising: a crucible block adapted to hold a crucible containing a solid mixture including one or more radionuclides; a lower heating block comprising one or more lower heating elements configured to selectively generate heat having a first temperature sufficient to at least partially sublimate the solid mixture; an upper heating block thermally insulated from the lower heating block; a collection vessel coupled to the upper heating block, the upper heating block comprising one or more upper heating elements configured to selectively generate heat to heat the collection vessel; and one or more cooling passages formed through the upper heating block. and one or more cooling passages configured to selectively direct a cooling fluid towards a collection vessel to facilitate condensation of the metal vapor, wherein the crucible block is movable relative to the lower heating block between an open position in which the crucible block is spaced apart from the lower heating block and the collection vessel and a closed position in which the crucible block is at least partially disposed within the lower heating block and the collection vessel is in fluid communication with the crucible, and wherein when the crucible block is in the closed position, the one or more lower heating elements are configured to heat the crucible block to a first temperature, thereby heating the solid mixture and generating a vapor that is collected by the collection vessel and leaving a solid residue in the crucible consisting essentially of only one or more radionuclides.

[0083] Aspect 22. A sublimation apparatus adapted to be disposed in a shielded environment and configured to be remotely controlled from outside the shielded environment, the sublimation apparatus comprising: a crucible block adapted to hold a crucible; a collection container containing vapor condensate; and a heating block coupled to the collection container and comprising one or more heating elements configured to selectively generate heat having a temperature sufficient to melt the vapor condensate in the collection container, wherein the crucible block is movable relative to the heating block between an open position in which the crucible block is spaced from the heating block and the collection container and a closed position in which the collection container is in fluid communication with the crucible, and wherein when the crucible block is in the closed position, the one or more heating elements are configured to heat the heating block surrounding the collection container and the crucible block to a first temperature, thereby melting substantially all of the metal vapor in the collection container and the crucible collecting the melted vapor condensate.

Claims

1. 1. A sublimation apparatus adapted to be disposed in a shielded environment and configured to be remotely controlled from outside the shielded environment, the sublimation apparatus comprising: a crucible block adapted to hold a crucible containing a solid mixture including one or more radionuclides; a first heating block comprising one or more first heating elements configured to selectively generate heat having a first temperature sufficient to at least partially sublimate the solid mixture; a collection container coupled to the first heating block; the crucible block is movable relative to the first heating block between an open position in which the crucible block is spaced from the first heating block and the collection vessel, and a closed position in which the crucible block is at least partially disposed within the first heating block and the collection vessel is in fluid communication with the crucible; a sublimation apparatus, wherein the one or more first heating elements are configured to heat the crucible block to the first temperature when the crucible block is in the closed position, thereby heating the solid mixture and producing a vapor that is collected by the collection vessel, leaving a solid residue in the crucible consisting essentially of the one or more radionuclides.

2. 10. The sublimation apparatus of claim 1, further comprising a second heating block thermally insulated from the first heating block, the second heating block comprising one or more second heating elements configured to selectively generate heat having a second temperature sufficient to melt the vapor condensate collected by the collection vessel.

3. 3. The sublimation apparatus of claim 2, wherein when the crucible block is in the closed position, the one or more second heating elements are configured to generate the heat having the second temperature to melt the vapor condensate collected by the collection vessel and return the melted vapor condensate to the crucible.

4. 3. The sublimation apparatus of claim 2, wherein the second heating block surrounds an upper portion of the collection vessel.

5. 5. The sublimation apparatus of claim 2 or 4, further comprising one or more cooling passages formed immediately adjacent to the second heating block, the one or more cooling passages configured to selectively direct cooling fluid toward the collection vessel to facilitate condensation of the vapor.

6. 5. A sublimation apparatus according to any one of claims 1 to 4, wherein the crucible block further comprises a sealing element configured to seal the crucible from the ambient environment when the crucible block is in the closed position.

7. 7. The sublimation apparatus of claim 6, further comprising a compensator assembly operably coupled to said crucible block, said compensator assembly comprising one or more springs configured to apply a constant load to said sealing element.

8. 8. The sublimation apparatus of claim 7, further comprising a plurality of compensator shafts coupled to the first heating block and to the compensator assembly, wherein the crucible block is movable between the open position and the closed position relative to the first heating block via the plurality of compensator shafts.

9. 9. The sublimation apparatus of any one of claims 1 to 4, 7 and 8, further comprising a drive assembly operatively coupled to said crucible block to move said crucible block between said open position and said closed position.

10. the drive assembly: A screw jack and a jackscrew shaft operably coupled to the jackscrew and to the crucible block; a drive motor configured to drive the jackscrew to move the jackscrew shaft and thereby move the crucible block between the open position and the closed position; a slip clutch installed between the drive motor and the screw jack; 10. The sublimation apparatus of claim 9, comprising:

11. 1. A sublimation apparatus adapted to be disposed in a shielded environment and configured to be remotely controlled from outside the shielded environment, the sublimation apparatus comprising: a crucible block adapted to hold a crucible containing a solid mixture including one or more radionuclides; a lower heating block comprising one or more lower heating elements configured to selectively generate heat having a first temperature sufficient to at least partially sublimate the solid mixture; an upper heating block thermally insulated from the lower heating block; a collection container coupled to the upper heating block; the crucible block is movable relative to the lower heating block between an open position in which the crucible block is spaced apart from the lower heating block and the collection vessel, and a closed position in which the crucible block is at least partially disposed within the lower heating block and the collection vessel is in fluid communication with the crucible; the one or more lower heating elements are configured to heat the crucible block to the first temperature when the crucible block is in the closed position, thereby heating the solid mixture and producing a vapor that is collected by the collection vessel, leaving a solid residue in the crucible consisting essentially of the one or more radionuclides; the upper heating block comprising one or more upper heating elements configured to selectively generate heat having a second temperature sufficient to melt the vapor condensate collected in the collection vessel.

12. 12. The sublimation apparatus of claim 11, further comprising one or more cooling passages formed through the upper heating block, the one or more cooling passages configured to selectively direct a cooling fluid toward the collection vessel to facilitate condensation of the vapor.

13. The sublimation apparatus of claim 12 , further comprising an air blower fluidly coupled to the one or more cooling passages and configured to direct the cooling fluid through the one or more cooling passages.

14. 14. The sublimation apparatus of claim 12 or 13, further comprising one or more exhaust passages formed between the upper heating block and the lower heating block, the one or more exhaust passages fluidly coupled to the one or more cooling passages to exhaust the cooling fluid.

15. Sublimation apparatus according to any one of claims 11 to 13, wherein the crucible block further comprises a sealing element configured to seal the crucible from the ambient environment when the crucible block is in the closed position.

16. 16. The sublimation apparatus of claim 15, further comprising a compensator assembly operably coupled to said crucible block, said compensator assembly comprising one or more springs configured to apply a constant load to said sealing element.

17. 17. The sublimation apparatus of claim 16, further comprising a plurality of compensator shafts coupled to the heating block and to the compensator assembly, wherein the crucible block is movable between the open position and the closed position relative to the heating block via the plurality of compensator shafts.

18. 18. The sublimation apparatus of any one of claims 11-13, 16 and 17, further comprising a drive assembly operatively coupled to said crucible block to move said crucible block between said open position and said closed position.

19. 18. The sublimation apparatus of claim 11, wherein the second temperature is substantially equal to the first temperature.

20. 1. A sublimation apparatus adapted to be disposed in a shielded environment and configured to be remotely controlled from outside the shielded environment, the sublimation apparatus comprising: a crucible block adapted to hold a crucible containing a solid mixture including one or more radionuclides; a lower heating block comprising one or more lower heating elements configured to selectively generate heat having a first temperature sufficient to at least partially sublimate the solid mixture; an upper heating block thermally insulated from the lower heating block; a collection container coupled to the upper heating block, the upper heating block including one or more upper heating elements configured to selectively generate heat to heat the collection container; one or more cooling passages formed through the upper heating block; the crucible block is movable relative to the lower heating block between an open position in which the crucible block is spaced apart from the lower heating block and the collection vessel, and a closed position in which the crucible block is at least partially disposed within the lower heating block and the collection vessel is in fluid communication with the crucible; the one or more lower heating elements are configured to heat the crucible block to the first temperature when the crucible block is in the closed position, thereby heating the solid mixture and producing a vapor that is collected by the collection vessel, leaving a solid residue in the crucible consisting essentially of the one or more radionuclides; The one or more cooling passages are configured to selectively direct cooling fluid toward the collection vessel to facilitate condensation of the vapor collected by the collection vessel.

21. 1. A sublimation apparatus adapted to be disposed in a shielded environment and configured to be remotely controlled from outside the shielded environment, the sublimation apparatus comprising: a crucible block adapted to hold a crucible; a collection vessel containing the steam condensate; a heating block coupled to the collection vessel and comprising one or more heating elements configured to selectively generate heat having a temperature sufficient to melt the vapor condensate within the collection vessel; the crucible block is movable relative to the heating block between an open position in which the crucible block is spaced from the heating block and the collection vessel, and a closed position in which the collection vessel is in fluid communication with the crucible; the one or more heating elements are configured to heat the collection vessel to the first temperature when the crucible block is in the closed position, thereby melting substantially all of the vapor condensate in the collection vessel; A sublimation apparatus wherein the crucible collects the molten vapor condensate.

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