The present invention relates to systems and methods for radiation shielding.
Electronics are exposed to radiation in many different environments. For example, electronics in space (e.g., in satellites) are subject to space radiation such as cosmic rays or solar weather. Similarly, electronics near nuclear reactors and other radioactive terrestrial sources can also face radiation. Radiation, and in particular ionizing radiation, can damage electronics through a variety of mechanisms. Single event effects, for instance, can range from a relatively minor output error or bit flip to permanent hardware damage/failure. As such, many electronics are routinely threatened by exposure to radiation. Smaller electronic are at even higher risk as they can suffer radiation damage relatively quickly.
In one form, an apparatus for radiation shielding is provided. The apparatus includes a first housing element and a first plurality of magnetic elements arranged in a first array on the first housing element. The first array is configured to generate a first tapered magnetic field and, using the first tapered magnetic field, deflect incoming radiation away from a protected element.
In one example, the first plurality of magnetic elements includes a first plurality of multipole magnets. The first plurality of multipole magnets may include a first plurality of quadrupole magnets. In a first example, the first plurality of magnetic elements includes a first plurality of magnetic elements having octagonal cross-sections. In a second example, the first plurality of magnetic elements includes a first plurality of C-hairpin-shaped magnets. The first plurality of C-hairpin-shaped magnets may include a first plurality of nested or interlocking C-hairpin-shaped magnets.
In another example, the apparatus further comprises a second housing element and a second plurality of magnetic elements arranged on the second housing element in a second array between the first array and the protected element. The second array is configured to generate a second tapered magnetic field and, using the second tapered magnetic field, deflect the incoming radiation away from the protected element. The first and second arrays may be configured to generate a magnetic bottle to contain the radiation. Furthermore, the first tapered magnetic field may be crossed with the second magnetic field.
In another form, a method of radiation shielding is provided. The method includes the steps of positioning a first array of magnetic elements between an element to be protected and a radiation source; using the first array of magnetic elements to generate a first tapered magnetic field; and using the first tapered magnetic field, deflecting incoming radiation away from a protected element.
The array of the plurality of magnetic elements 220 is configured to generate a tapered magnetic field 230. In the example shown in
A radiation shield as described herein may be any suitable substantially two-dimensional shape (e.g., square, polygon, etc.), an example of which is illustrated in
The plurality of magnetic elements 220 may have poles in a common plane such that arrays of opposing pairs of north poles are symmetric about the center of wafer 292, with interleaved arrays of pairs of south poles. This magnetic fringing may distribute the magnetic field in the volume between opposing pole tips. The tapered magnetic field 230 may be produced by varying the strength and/or tilt of the plurality of magnetic elements 220 from the center to the edge of the wafer 292.
The plurality of magnetic elements 220 may be any suitable shape. For example, the plurality of magnets 220 may be generally circular, having an outer edge circumscribed by a generally circular component (e.g., wafer 292). Examples of other suitable shapes include gradients, cylinders, disks, etc. The plurality of magnetic elements 220 may have cross sections of any suitable regular polygon having any suitable number of sides. The plurality of magnetic elements 220 may also/alternatively have cross-sections of circular or any other suitable shape. Furthermore, the plurality of magnets 220 may include magnetic materials such as AlNiCo5, Sm2Co17, NdFeB, SrFe12O19, etc.
The plurality of magnetic elements 220 may be permanent or electromagnetic magnets. In one example, each magnetic element in the plurality of magnetic elements 220 may be individually controllable to provide dynamic flexibility to radiation shield 210/240. For example, individual control may enable the array of the plurality of magnetic elements 220 to generate tapered magnetic field 230 by producing combined dipole-quadrupole fields (e.g., dipole field strength and quadrupole field gradient). The array of the plurality of magnetic elements 220 may be matched in size and scale to anticipated external radiation intensity/source and payload sensitivities as appropriate.
Ring 320 may be any suitable material to secure spokes 330(1)-330(4) and windings 340(1)-340(4) without interfering with the magnetic field produced by magnetic element 310. Spokes 330(1)-330(4) may be magnetic yokes to enhance the magnetic field (e.g., permalloy 80/20). In one example, the magnetic yokes may be grown inside windings 340(1)-340(4). Windings 340(1)-340(4) may include any suitable conductor (e.g., copper). Windings 340(1)-340(4) may include an insulating/supporting material (e.g., dielectric) between the windings 340(1)-340(4) to prevent contact between/among the windings 340(1)-340(4).
Magnetic element 310 may be manufactured using combined fabrication techniques developed for integrated circuits and memory. Magnetic element 310 may also be separated by die singulation and packaged using flip chip methods. Alternatively, magnetic element 310 may be laser-machined into a permanent magnet array with spatially alternating magnetic fields.
Radiation shield 510 further includes a second plurality of magnetic elements 530 and housing element 535. The second plurality of magnetic elements 530 are arranged in a second array on housing element 535. The second array of the plurality of magnetic elements 530 is disposed between the first array of the plurality of magnetic elements 520 and the protected element 515. The plurality of magnetic elements 530 may be arranged in the second array by wafer 532. In this example, wafer 532 is wider than wafer 528, and the first array of the plurality of magnetic elements 520 is wider than the second array of the plurality of magnetic elements 530.
The first array of the plurality of magnetic elements 520 is configured to generate a tapered magnetic field 534. Tapered magnetic field 534 may be a magnetic vortex with a magnetic pinch near first plurality of magnetic elements 520. Using tapered magnetic field 534, the array of the plurality of magnetic elements 520 is further configured to deflect incoming radiation 505 away from protected element 515, as illustrated at 540. Similarly, the second array of the plurality of magnetic elements 530 is configured to generate a tapered magnetic field 545. Using tapered magnetic field 545, the array of the plurality of magnetic elements 530 is further configured to deflect incoming radiation 505 away from protected element 515, as illustrated at 550. The first array of the plurality of magnetic elements 520 and the second array of the plurality of magnetic elements 530 may be configured to generate a magnetic bottle 555 to contain/trap incoming radiation 505.
In one example, incoming radiation 505 includes particles having trajectories greater than and less than 5 degrees relative to the perpendicular direction to housing elements 525 and 535. The particles may have a velocity aimed at the first array of the plurality of magnetic elements 520. The first array of the plurality of magnetic elements 520 may deflect particles having trajectories greater than 5 degrees at angles greater than 30 degrees, as illustrated at 540. The first array of the plurality of magnetic elements 520 may also be arranged to form a gap 560 through which stronger incoming radiation 505 (e.g., particles having trajectories less than 5 degrees pass) may pass. The second array of the plurality of magnetic elements 530 may deflect particles having trajectories less than 5 degrees through weep holes in the first array of the plurality of magnetic elements 520 (e.g., similar to weep holes 296 and 298 as illustrated in
Radiation shield 610 further includes a second plurality of magnetic elements 635 and housing element 640. The second plurality of magnetic elements 635 are arranged in a second array on housing element 640. The second array of the plurality of magnetic elements 635 is disposed between the first array of the plurality of magnetic elements 620 and the protected element 615. The plurality of magnetic elements 635 may be arranged in the second array in a substantially ovular shape by wafer 640.
The first array of the plurality of magnetic elements 620 is configured to generate a tapered magnetic field 650. Using tapered magnetic field 650, the first array of the plurality of magnetic elements 620 is further configured to deflect incoming radiation 605 away from protected element 615. Similarly, the second array of the plurality of magnetic elements 635 is configured to generate a tapered magnetic field 655. Using tapered magnetic field 655, the second array of the plurality of magnetic elements 635 is further configured to deflect incoming radiation 605 away from protected element 615.
Tapered magnetic fields 650 and 655 may be cylindrically asymmetric. This may be accomplished by tilting housing element 640 with respect to housing elements 625 and 665. In one example, tapered magnetic field 650 may be crossed with tapered magnetic field 655. Because the first array of the plurality of magnetic elements 620 and the second array of the plurality of magnetic elements 635 both produce distorted magnetic funnels, toggling of the first array of the plurality of magnetic elements 620 and the second array of the plurality of magnetic elements 635 may enable control over the directionality of magnetic funnels. For example, varying the power supplied over the first array of the plurality of magnetic elements 620 may cause tapered magnetic field 650 to take on a specific shape/orientation.
Radiation shield 610 further includes a third plurality of magnetic elements 660 and housing element 665. The third plurality of magnetic elements 660 are arranged in a third array on housing element 665. The third array of the plurality of magnetic elements 635 is disposed between the second array of the plurality of magnetic elements 635 and the protected element 615. The plurality of magnetic elements 660 may be arranged in the third array by wafer 670. The third array of the plurality of magnetic elements 660 is configured to generate a tapered magnetic field 675. Using tapered magnetic field 675, the array of the plurality of magnetic elements 660 is further configured to deflect incoming radiation 605 away from protected element 615. The third array of the plurality of magnetic elements 660 and the second array of the plurality of magnetic elements 635 may be configured to generate a magnetic bottle 680 to contain/trap incoming radiation 605.
In one example, incoming radiation 605 with a trajectory greater than 5 degrees has a velocity aimed at the first array of the plurality of magnetic elements 620 and the second array of the plurality of magnetic elements 635, which deflect that incoming radiation 505 at angles greater than 30 degrees. The first array of the plurality of magnetic elements 620 may be arranged to form a gap 685 through which stronger incoming radiation 605 with a trajectory less than 5 degrees may pass. Similarly, the second array of the plurality of magnetic elements 635 may be arranged to form a gap 690 through which stronger incoming radiation 605 with a trajectory less than 5 degrees may pass. The third array of the plurality of magnetic elements 660 may deflect that incoming radiation 605 through weep holes in the first array of the plurality of magnetic elements 620 and/or weep holes in the first array of the plurality of magnetic elements 635 (e.g., similar to weep holes 296 and 298 as illustrated in
In one example, incoming radiation 810 is a sheet of incident electrons, and the magnetic field at the center of magnet element 820 is 1.9E-3 T. Electrons incident at an off z-axis distance of greater than 4 mm are reflected back. Electrons incident at an off z-axis distance of 4 mm contacts the magnet pupil radius of 3 mm. Electrons incident at an off z-axis distance of less than 4 mm passes through magnet pupil radius (e.g., at 2 mm).
In another embodiment, a second array of magnetic elements may be positioned between the first array of magnetic elements and the element to be protected. In yet another embodiment, a third array of magnetic elements may be positioned between the second array of magnetic elements and the element to be protected. In still another embodiment, the protected element may be positioned within a housing, and at least a first plurality of magnetic elements may be arranged on the housing in a first array configured to generate a first tapered magnetic field of increasing size in a direction away from the housing. In another embodiment, the housing may include a plurality of housing elements, and the method may include arranging a plurality of magnetic elements in an array on each of the housing elements. In an additional embodiment, respective arrays on the plurality of housing elements may generate respective tapered magnetic fields in different directions.
In one form, an apparatus for radiation shielding is provided. The apparatus includes a first housing element and a first plurality of magnetic elements arranged in a first array on the first housing element. The first array is configured to generate a first tapered magnetic field and, using the first tapered magnetic field, deflect incoming radiation away from a protected element.
In one example, the first plurality of magnetic elements includes a first plurality of multipole magnets. The first plurality of multipole magnets may include a first plurality of quadrupole magnets. In a first example, the first plurality of magnetic elements includes a first plurality of magnetic elements having octagonal cross-sections. In a second example, the first plurality of magnetic elements includes a first plurality of C-hairpin-shaped magnets. The first plurality of C-hairpin-shaped magnets may include a first plurality of nested or interlocking C-hairpin-shaped magnets.
In another example, the apparatus further comprises a second housing element and a second plurality of magnetic elements arranged on the second housing element in a second array between the first array and the protected element. The second array is configured to generate a second tapered magnetic field and, using the second tapered magnetic field, deflect the incoming radiation away from the protected element. The first and second arrays may be configured to generate a magnetic bottle to contain the radiation. Furthermore, the first tapered magnetic field may be crossed with the second magnetic field.
The plurality of magnetic elements may include magnets of any suitable type. For example, the magnets may be multipole magnets (e.g., quadrupole, sextupole, octupole, etc.). The magnetic elements may have any suitable shape/cross-section, such as circular, octagonal, C-hairpin-shaped, gradient, cylinder, disk, etc. The magnetic elements may be staged circular hollow magnets, in one example. Furthermore, the plurality of magnet elements may include any suitable magnetic material (e.g., AlNiCo5, Sm2Co17, NdFeB, SrFe12O19, etc.). The plurality of magnetic elements may be permanent or electromagnetic magnets. If electromagnets are used, the tapered magnetic field may be steered in different directions relative to the plane of the array, e.g., using phase array techniques, as opposed to being fixed at a particular angle relative to the plane of the array. The strength(s) of the magnetics may be proportional to the energy of incoming radiation, which may be determined based on the mass, electric charge, and velocity of the incoming radiation. In one example, magnets used in an array on a silicon wafer may each be on a sub-millimeter scale and produce 100 mT local magnetic fields. In another example, permanent magnets (e.g., Nd2FE14B) may be 100 T/m locally across 3 mm.
An array may include any suitable number of magnetic elements. For example, the array may include only one or two magnetic elements. Alternatively, the magnetic elements in a given array may number in the hundreds or thousands. The arrays may be generally circular, ovular, polygonal, any combination of the foregoing, etc. Furthermore, the housing element may comprise a single housing element or multiple housing elements. The housing may be spherical, cylindrical, square, pyramidal, any combination of the foregoing, etc.
One or more features disclosed herein may be implemented in, without limitation, circuitry, a machine, a computer system, a processor and memory, a computer program encoded within a computer-readable medium, and/or combinations thereof. Circuitry may include discrete and/or integrated circuitry, application specific integrated circuitry (ASIC), field programmable gate array (FPGA), a system-on-a-chip (SOC), and combinations thereof.
Methods and systems are disclosed herein with the aid of functional building blocks illustrating functions, features, and relationships thereof. At least some of the boundaries of these functional building blocks have been arbitrarily defined herein for the convenience of the description. Alternate boundaries may be defined so long as the specified functions and relationships thereof are appropriately performed. While various embodiments are disclosed herein, it should be understood that they are presented as examples. The scope of the claims should not be limited by any of the example embodiments disclosed herein.
What has been described above are examples. It is, of course, not possible to describe every conceivable combination of components or methodologies, but one of ordinary skill in the art will recognize that many further combinations and permutations are possible. Accordingly, the disclosure is intended to embrace all such alterations, modifications, and variations that fall within the scope of this application, including the appended claims. As used herein, the term “includes” means includes but not limited to, the term “including” means including but not limited to. The term “based on” means based at least in part on. Additionally, where the disclosure or claims recite “a,” “an,” “a first,” or “another” element, or the equivalent thereof, it should be interpreted to include one or more than one such element, neither requiring nor excluding two or more such elements.
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