Shielding device

Abstract

A shielding apparatus (101) including a device (103) and a shielding (105), and a method of producing the shielding apparatus. The device (103) attenuates x-rays by different amounts in different portions of the device (103), providing a first span of x-ray attenuation. The shielding (105) includes a layer (109) of x-ray attenuating material that attenuates x-rays by amounts that vary across the shielding (105), providing a second span of attenuation. The second span of attenuation has a magnitude between 20% and 120% of the magnitude of the first span of attenuation.

Description

[Technical Field]

[0001] The present disclosure relates to a shielding apparatus including a device and a shielding body including a layer of X-ray attenuating material. The present disclosure also relates to a method of producing the shielding apparatus. [Background technology]

[0002] Safety devices may need to be shielded so that they are invisible and cannot be detected or identified during use, deployment, or transportation, or at least so that they do not leave any evidence of detection or identification. Shielding can be used to block visible light and can ensure that devices are invisible during use, deployment, and transportation. Such shielding can be used temporarily, for example, during deployment or transportation, or can be permanently positioned to shield devices. Known shielding is, for example, a plate, box, or container. The type, size, and material used for such shielding typically depend on the device to be shielded and the level of protection required. However, known shielding may not provide protection against methods of detecting devices other than visible light. For example, X-ray radiation can be used to detect, identify, and image devices, and conventional shielding may not provide protection against X-ray radiation, and the use of X-ray radiation generally does not leave any traces on the device or shielding, making it unclear that X-rays were used. Thus, third parties may be able to use X-rays to detect, identify, and image devices without the knowledge of authorized users of the devices.

[0003] X-ray attenuating materials are known and used in various fields to fully or partially attenuate X-ray radiation. To adequately block X-rays, heavy, large, and cumbersome shielding is typically required. Shielding that partially attenuates X-rays is used to provide some degree of protection to devices. Shielding that introduces an obstructive pattern or message into an X-ray generated image is known. While this may provide some protection against detection and / or identification of the device, there are known techniques for compensating for such patterns / messages (such as simply subtracting the pattern or message from the X-ray image), and therefore this is not a robust and reliable method for shielding devices from X-rays. Summary of the Invention [Problem to be solved by the invention]

[0004] Therefore, there is a need to develop improved and more robust methods of shielding devices from X-ray detection. [Means for solving the problem]

[0005] According to a first aspect, the present disclosure provides a shielding device according to claim 1.

[0006] The present disclosure provides, according to a fifth aspect, a method for producing a shielding device according to claim 19.

[0007] It will be appreciated that features described in connection with one aspect of the present disclosure may be incorporated into other aspects of the present disclosure, for example, a method of the present disclosure may incorporate features described with reference to an apparatus of the present disclosure, and vice versa. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic side view of a shielding device known in the art; [Figure 2] 1 is a schematic side view of a shielding device according to an embodiment of the present disclosure. [Figure 3a]1 is a perspective view of a shield for use in a shielding device according to an embodiment of the present disclosure. FIG. [Figure 3b] 3(b) is a schematic cross-sectional side view through a shielding device using the shield of FIG. 3(a) according to an embodiment of the present disclosure. [Figure 4] 1 is a schematic cross-sectional side view through a shielding apparatus according to an embodiment of the present disclosure, wherein the shielding comprises a suspension of X-ray attenuating particles distributed within a substrate, with an air gap between the substrate and the device. [Figure 5] 1 is a schematic cross-sectional side view through a shielding apparatus according to an embodiment of the present disclosure, wherein the shielding comprises a suspension of X-ray attenuating particles distributed within a substrate and there is no air gap between the substrate and the device. [Figure 6] 1 is a schematic cross-sectional side view through a shielding device according to an embodiment of the present disclosure, where the shielding includes a suspension of X-ray attenuating particles within a box. [Figure 7] 1 is a schematic diagram illustrating the use of a shielding apparatus according to an embodiment of the present disclosure when attempting to image a device using X-rays. [Figure 8] 1 is a plan view of a shield for use in a shielding apparatus according to an embodiment of the present disclosure, in which a portion of the shield has a non-random variation in x-ray attenuation, according to an embodiment of the present invention. FIG. [Figure 9] The shield forms a lid for a box, a shielding device according to an embodiment of the present disclosure. [Figure 10] The shielding is a box, the device is a missile, and the box has a layer of x-ray attenuating material added to each wall, which is a shielding apparatus according to an embodiment of the present disclosure. [Figure 11] The shielding is a briefcase, the device is a secret prototype, and the briefcase is a shielding apparatus according to an embodiment of the present disclosure having a layer of x-ray attenuating material contained within its lining. [Figure 12] The shielding is a safe, the device is a laptop, and the briefcase is a shielding apparatus according to an embodiment of the present disclosure having a layer of x-ray attenuating material within its lining. [Figure 13] 1 is a flow chart illustrating a method for generating a shielding device according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] According to a first aspect, the present disclosure provides a shielding apparatus including a device that attenuates X-rays by different amounts in different portions of the device, providing a first span of X-ray attenuation. The apparatus includes a shielding body that includes a layer of X-ray attenuating material that attenuates X-rays by varying amounts across the shielding body, providing a second span of X-ray attenuation. The second span of attenuation has a magnitude that is between 20% and 120% of the magnitude of the first span of attenuation.

[0010] The device may include one or more electronic components, such as a circuit board, and electrical board or circuit board components. The device may include multiple copper components, silicon components, and / or wires that may have different attenuation. The device may be a mechanical device. The device may be a weapon, e.g., a missile. The device may be a vehicle component, such as an engine. The device may be a computer. The device may be a laptop computer. The device may be a classified prototype.

[0011] The device may include different materials having different X-ray attenuation coefficients and / or different thicknesses of material, resulting in a first span of X-ray attenuation. The X-ray attenuation of the device may differ for different parts of the device, for example, due to the presence of surface features or regions comprising different materials or different thicknesses of material. For example, the device may be a circuit board containing multiple features. The features may result in X-ray attenuation that varies across the device.

[0012] Similarly, the x-ray attenuating layer may have varying thicknesses and / or comprise different materials with different x-ray attenuation coefficients, resulting in a second span of x-ray attenuation.

[0013] The second attenuation span has a magnitude between 20% and 100% of the first attenuation span. If x-rays are to be used to image the device, the layer of x-ray attenuating material further attenuates the x-rays used to form the image.

[0014] The shielding may be positioned relative to the device such that, when attempting to image the device using x-rays, the shielding blocks the x-rays before and / or after they enter the device. When attempting to image the device using x-rays, the layer of x-ray attenuating material may introduce a pattern of noise into the image, which may cause parts of the image to be undersaturated and other parts of the image to be oversaturated.

[0015] The second attenuation span may have a minimum attenuation within the first span of attenuation. The second attenuation span may have a minimum attenuation equal to or comparable to the maximum attenuation of the first span of attenuation, such that the shielding is more attenuating than the device being shielded. The second span of attenuation may have a minimum attenuation up to twice the maximum attenuation within the first span of attenuation. The shielding may therefore be at least twice the attenuation of the device being shielded.

[0016] The layer of x-ray attenuating material may have a thickness variation across the shield. The thickness variation across the shield may depend on the device being shielded, the expected energy of x-rays that may be used to image the device, and the material used to form the shield. For example, a shield for shielding electronic circuit boards may have an x-ray attenuating layer with a thickness that varies between 0.1 mm and 1 mm. A shield for shielding engine components may have an x-ray attenuating layer with a thickness that varies between 0.1 mm and 400 mm. The thickness variation across the shield may be stepped. The x-ray attenuating layer may include multiple pixels of x-ray attenuating material, the pixels having different thicknesses.

[0017] The variation in X-ray attenuation across the shielding may be of the same or similar magnitude to the variation in X-ray attenuation across the device, and thus, when attempting to image the device using X-rays, the shielding may introduce a pattern of noise that obscures the image of the device.

[0018] X-ray attenuation may vary randomly across the shielding. Thus, when attempting to image a device using X-rays, the shielding may introduce a random pattern of noise into an image of the device. The attenuation of the X-ray attenuating material may vary randomly across all of the shielding. Thus, when attempting to image a device using X-rays, the shielding may obscure the entire image of the device. The attenuation of the X-ray attenuating material may vary randomly across portions of the shielding. Thus, when attempting to image a device using X-rays, the shielding may obscure a portion of the image of the device. Portions of the shielding may have non-random variations in X-ray attenuation, thereby generating an encoded message in an image formed by X-rays passing through the shielding. The encoded message may be a text-based message.

[0019] The selection of the x-ray attenuating material and / or the thickness of the x-ray attenuating material may depend on the device being shielded and / or the likely range of x-ray energies that may be used to image the device. The thickness and / or selection of the x-ray attenuating material used in the shielding is selected such that the second attenuation span is between 20% and 120% of the first x-ray attenuation span.

[0020] The layer of x-ray attenuating material may comprise a continuous layer. The layer of x-ray attenuating material may be applied to a surface of the shield. The layer of x-ray attenuating material may partially or entirely cover the surface of the shield.

[0021] The layer of x-ray attenuating material may include a coating applied to a substrate. The shield may include a substrate, which may be a material that does not significantly attenuate x-rays. The substrate may be a resin or binder.

[0022] The shield may include regions of X-ray attenuating material dispersed within the substrate material. The particles may be suspended within the substrate material. The substrate may be solid or liquid. The shield may further include a closed box to contain the substrate. The substrate may be a binder, such as a resin. The substrate may include a material that does not significantly attenuate X-rays. The regions of X-ray attenuating material may be particles, such as powder particles. The shield may therefore include multiple X-ray attenuating particles dispersed within the substrate. The regions of X-ray attenuating material may be 3D printed microstructures or shapes. The regions may be of the same size and shape or may have different sizes and shapes, thus resulting in different levels of X-ray attenuation. Particles of different sizes and shapes may serve to obscure different sized features of the device. The regions may include different materials. The regions may be copper particles or tungsten particles.

[0023] The shielding may include a plurality of X-ray attenuating particles provided within a box. The particles may be free to move within the box. The particles may be free to move in at least one direction within the box. The particles may be free to move in all directions within the box. The particles may be repositionable relative to one another within the box. The particles may be of the same size and shape, or may have different sizes and shapes and therefore may result in different levels of X-ray attenuation. The particles may be of the same X-ray attenuating material, or may be of multiple different X-ray attenuating materials. The particles may include powder particles. The particles may include 3D printed microstructures or shapes. Particles of different sizes and shapes may serve to obscure different sized features of the device. The shielding may further include a support frame for positioning the box relative to the device.

[0024] The shielding may include a combination of particles dispersed within a plurality of x-ray attenuating regions or substrates and a variation in thickness of x-ray attenuating material across the shielding. The variation in thickness may be gradual resulting from a plurality of pixels or rows of pixels. The particles dispersed within the plurality of x-ray attenuating regions or solid substrate may be formed into rows of varying thickness, and these rows may be distributed across the shielding.

[0025] The shield may be a panel, plate, or box. The shield may be a briefcase, a safe, or a shipping container. The shield may be a flat panel or a curved panel. The shield may comprise multiple adjacent or connected panels. The shield may form part of a box, safe, briefcase, or container, for example the shield may be or form part of the lid of a container or box. The shield may be a box with a removable and / or resealable lid for removing and / or inserting a device.

[0026] The shielding may be for temporarily shielding the device, for example, during transportation, deployment, or storage. The shielding may be removably attached to the device or fixed to the device. The shielding may be a more permanent structure to protect the device during use or storage. The shielding may be positioned in front of the device so that when an X-ray is used to image the device, the shielding may block the X-rays before they reach the device. The shielding may be positioned behind the device so that when an X-ray is used to image the device, the shielding may block the X-rays before they are used to form an image of the device. The shielding may completely or partially surround the device. The shielding may be in direct contact with the device. There may be an air gap between the shielding and the device. Alternatively, there may be no air gap between the shielding and the device. The shielding may be welded or screwed to the device. The shielding may be a plate comparable in size to the device or slightly larger than the device.

[0027] The layer of x-ray attenuating material includes a material selected from the list consisting of titanium, iron, nickel, copper, zinc, barium, tungsten, mercury, lead, bismuth, and uranium. The thickness of the layer of x-ray attenuating material may depend on the choice of material. For example, uranium attenuates x-rays more strongly than titanium, so a thinner layer of uranium may be used to achieve the same attenuation as a thicker layer of titanium. The x-ray attenuating material may include multiple different materials. The material may be selected depending on the device to be shielded. The choice of material and the thickness of the material may depend on the potential range of x-ray energies that may be used when attempting to image the device.

[0028] According to a second aspect, the present disclosure provides a method of producing a shielding device. The shielding device includes a device that attenuates X-rays by different amounts in different portions of the device, providing a first span of X-ray attenuation. The device includes a shielding body. The shielding body includes a layer of X-ray attenuating material that attenuates X-rays by a varying amount across the shielding body, providing a second span of X-ray attenuation. The shielding device may include any feature described above. The method includes generating a variation in attenuation across the layer of X-ray attenuating material, the second attenuation span having a magnitude between 20% and 120% of the magnitude of the first attenuation span. The method includes adding a layer of X-ray attenuating material to the shielding body. The method includes positioning the shielding body relative to the device such that when the device is to be imaged using X-rays, the shielding blocks X-rays used to image the device.

[0029] If the shielding is a box, briefcase, safe, or container, placing the shielding relative to the device may include placing the device within the box, briefcase, safe, or container. The method may include sealing the box or container or closing the briefcase or safe. Placing the shielding relative to the device may include fully or partially enclosing the device with the shielding. Placing the shielding relative to the device may include positioning the shielding in front of the device such that, when attempting to image the device using x-rays, the shielding blocks x-rays before they reach the device. Placing the shielding relative to the device may include positioning the shielding behind the device. In this case, the shielding may block x-rays after they enter the device but before an image is formed using the x-rays.

[0030] Adding the layer of x-ray attenuating material to the shielding may include coating the layer on a substrate or on a surface of the shielding. Adding the layer of x-ray attenuating material to the shielding may include dispersing regions of the x-ray attenuating layer within the substrate. The method steps of generating the attenuating variations, adding the layer to the shielding, and positioning the shielding relative to the device may be performed in any order. For example, the layer may be added to the shielding before the step of generating the x-ray attenuating variations or after generating the x-ray attenuating variations.

[0031] Generating the variation in attenuation may include generating a variation in thickness across the layer of x-ray attenuating material. The variation in attenuation across the layer of x-ray attenuating material may be generated using additive layer manufacturing. This may be used to generate a continuous layer of x-ray attenuating material. The method may include adding the layer to a substrate that may form part of the shield. Using additive layer manufacturing may provide an efficient method of generating fine-scale variations in thickness. The variation in attenuation across the layer of x-ray attenuating material may be generated using CNC machining. The method may include using CNC machining to generate random variations in thickness across the shield. The variation in attenuation across the layer of x-ray attenuating material may be generated using a mold. Individual pixels may be cast and then assembled to form the layer of x-ray attenuating material. Alternatively, the layer of x-ray attenuating material may be cast as a whole. The manufacturing method may depend on the scale of thickness variation required.

[0032] Prior art shielding apparatus 1 (FIG. 1) includes a device 3 having a first span of X-ray attenuation and a shielding 5 provided in front of device 3. Shielding 5 has a constant thickness and includes a material that partially attenuates X-rays. X-ray attenuation across shielding 5 is therefore constant for X-rays of the same energy. When an image 7 of device 3 is to be formed using X-rays, X-rays directed in the direction of arrow 2 toward device 3 are blocked by shielding 5 before they enter device 3. Shielding 5 partially attenuates the X-rays before they enter device 3. When image 7 is formed using X-rays that have passed through device 3 and the shielding, the attenuation caused by the shielding uniformly reduces the contrast of image 7.

[0033] A shielding apparatus 101 according to a first exemplary embodiment of the present disclosure (FIG. 2) includes a device 103 and a shielding body 105 having a first span of X-ray attenuation. The shielding body 105 includes a layer of X-ray attenuating material 109 having a varying attenuation across the shielding body 105, providing a second span of attenuation. The second span of attenuation has a magnitude between 20% and 120% of the magnitude of the first attenuation span. The first attenuation span is provided by a plurality of features 104a, 104b provided on the surface of the device 103. These features 104a, 104b are formed from different materials and have different attenuation coefficients than the remainder of the device, locally increasing the thickness of the device 103.

[0034] A layer of x-ray attenuating material 109 is arranged on a substrate 111 that forms part of the shield 105. The layer of x-ray attenuating material includes a plurality of pixels 112 a, 112 b, 112 c, each pixel 112 a, 112 b, 112 c having a different thickness. The x-ray attenuating material 109 has a constant x-ray attenuation coefficient, but the different thicknesses across the layer 109 result in variations in attenuation across the layer 109.

[0035] Shielding 105 is positioned in front of device 103. When an image of the device is to be formed using X-rays, shielding 105 blocks X-rays directed toward the device (e.g., in the direction indicated by arrow 102). A layer of X-ray attenuating material 109 partially attenuates the X-rays, with thicker pixels (e.g., 112c) providing greater attenuation than thinner pixels (e.g., 112b). Because the thickness variation across the layer is random, this introduces a random pattern of noise into the X-rays incident on device 103. This in turn introduces a random pattern of noise, or a random reduction in contrast, into image 107 formed from the X-rays.

[0036] Using variations in attenuation across the shielding 105 to introduce a pattern of noise into an image formed from x-rays passing through the shielding 105 allows for the use of thinner, and therefore lighter, shielding than known shielding to effectively obscure the image. Using random variations in thickness across the shielding 105 helps prevent filtering of the image to remove noise introduced by the shielding 105.

[0037] A shield 205 for use in a shielding device 201 according to a second exemplary embodiment of the present disclosure (FIG. 3(a)) includes a layer 209 of X-ray attenuating material forming a plate and sidewalls 214a, 214b, 214c, and 214d extending perpendicularly from the plate. The layer 209 of X-ray attenuating material includes a plurality of pixels 212a, 212b having different thicknesses. The pixels 212a, 212b create variations in attenuation across the shield 205. The plate of the shield 205 has an area of ​​10 cm x 10 cm. Each pixel 212a, 212b is substantially cubic in shape. Each pixel 212a, 212b has an area in the plane of the plate of 0.5 μm x 0.5 μm to 1 mm x 1 mm. Each pixel 212a, 212b has a thickness (measured perpendicular to the plane of the plate) of 0.1 mm to 1 mm. In use, the shield 205 may be positioned in front of or above the circuit board 203 and soldered to the circuit board 203, as shown in Figure 3(b). When attempting to image the board using x-rays, x-rays may be used, which may have energies of approximately 40 keV to 100 keV. When an image is generated using x-rays that pass through the shield in the direction indicated by arrow 202, a random pattern of noise is introduced into the image as a result of the varying thickness of the pixels 212a, 212b.

[0038] In other embodiments (not shown), the shield may be screwed onto the electronic circuit board or electronic component, or may be temporarily placed on or in front of the electronic circuit board or electronic component.

[0039] A shielding apparatus 701 according to a second exemplary embodiment of the present disclosure (FIG. 4) includes a device 703 having a first span of X-ray attenuation and a shield 705. The shield 705 includes a plurality of X-ray attenuating copper particles 709a, 709b, and 709c suspended within a solid resin substrate 710. In other embodiments (not shown), the substrate may be a liquid substrate, and the substrate and particles may be enclosed within a container. The resin substrate 710 does not significantly attenuate X-rays. The X-ray attenuating particles 709a, 709b, and 709c have different sizes and shapes with diameters ranging from 10 μm to 10 mm and therefore attenuate X-rays by different amounts. The shield thereby provides a second span of attenuation. The second span of attenuation has a magnitude between 20% and 120% of the magnitude of the first attenuation span. The first attenuation span is provided by a plurality of features 704a and 704b provided on the surface of the device 703. In this case, device 703 is an electronic circuit board that is approximately 5 mm x 5 mm in area and includes multiple silicon components. These features 704a, 704b locally increase the thickness of device 703.

[0040] A shield 705 is positioned over device 703. When attempting to form an image of device 703 using X-rays, shield 705 blocks X-rays directed toward the device (e.g., in the direction indicated by arrow 702). X-ray attenuating particles 709a, 709b, 709c partially attenuate the X-rays, with larger particles (e.g., 709a) causing greater attenuation than smaller particles (e.g., 709b). Because the distribution of particles 709a, 709b, 709c is random, this introduces a random pattern of noise into the X-rays incident on device 703. This, in turn, introduces a random pattern of noise or a random reduction in contrast into the image formed from the X-rays.

[0041] A shielding apparatus 1001 according to a third exemplary embodiment of the present disclosure (FIG. 5) includes a device 1003 having a first span of X-ray attenuation and a shield 1005. The shield 1005 includes a plurality of X-ray attenuating copper particles 1009a, 1009b, 1009c suspended within a solid substrate 1010. The substrate 1010 does not significantly attenuate X-rays. X-ray attenuating particles1009a , 1009b , 1009c The shields 1003 have different sizes and shapes, with diameters ranging from 10 μm to 10 mm, and therefore attenuate the X-rays by different amounts. The shield 1005 thereby provides a second span of attenuation. The second span of attenuation has a magnitude that is 20% to 120% of the magnitude of the first attenuation span. The first attenuation span is provided by a plurality of features 1004 a, 1004 b provided on the surface of the device 1003. The device 1003 is an electronic substrate. These features 1004 a, 1004 b locally increase the thickness of the device 1003.

[0042] Shielding 1005 is positioned above and around device 1003. In contrast to shielding apparatus 701 shown in FIG. 4, there is no air gap between shielding 1005 and device 1003. When attempting to form an image of device 1003 using X-rays, shielding 1005 blocks X-rays directed toward the device. X-ray attenuating particles 1009a, 1009b, 1009c partially attenuate X-rays, with larger particles (e.g., 1009a) causing greater attenuation than smaller particles (e.g., 1009b). Because the distribution of particles 1009a, 1009b, 1009c is random, this introduces a random pattern of noise into the X-rays incident on device 1003. This, in turn, introduces a random pattern of noise or a random reduction in contrast into the image formed from the X-rays.

[0043] A shielding apparatus 801 according to a third exemplary embodiment of the present disclosure (FIG. 6) includes a device 803 having a first span of X-ray attenuation and a shield 805. The shield 805 includes a plurality of X-ray attenuating copper particles 809a, 809b, and 809c contained within a box 810. The particles 809a, 809b, and 809c are movable relative to one another within the box 810. The X-ray attenuating particles 809a, 809b, and 809c have different sizes and shapes, with diameters ranging from 10 μm to 10 mm, and therefore attenuate X-rays by different amounts. The shield 805 thereby provides a second span of attenuation provided by the distribution of the X-ray attenuating particles 809a, 809b, and 809c within the box 810. For example, if the device 801 is moved, the distribution of X-ray attenuating particles 809a, 809b, 809c may change, and therefore the variation in attenuation across the shield 805 may change when the device 801 is moved. The second span of attenuation has a magnitude that is 20% to 120% of the magnitude of the first attenuation span. The first attenuation span is provided by a plurality of features 804a, 804b provided on the surface of the device 803. These features 804a, 804b locally increase the thickness of the device 803. The device 803 is an electronic circuit board.

[0044] The shield 805 is 803 and suspended above the apparatus by a support frame 811. If an image of device 803 is to be formed using X-rays, shield 805 blocks X-rays directed towards the device. X-ray attenuating particles 809a, 809b, 809c partially attenuate the X-rays, with larger particles (e.g., 809a) attenuating the X-rays and smaller particles (e.g., 809b) resulting in greater attenuation. Because the distribution of particles 809a, 809b, 809c is random, this introduces a random pattern of noise into the x-rays incident on device 803. This in turn introduces a random pattern of noise or a random reduction in contrast into image 807 formed from the x-rays. If apparatus 801 is moved, the arrangement of x-ray attenuating particles 809a, 809b, 809c within box 810 may change, and shielding 805 may introduce a different pattern of noise into the x-rays incident on device 803 if an attempt is made to further image the device using x-rays.

[0045] 6, the X-ray attenuating copper particles 809a, 809b, 809c are contained within a box 810 suspended above the electronics board. In other embodiments, the X-ray attenuating particles may not be contained within a separate box. The walls of the shield may enclose the device and the X-ray attenuating particles within the same space.

[0046] In other embodiments of the present disclosure (not shown), the shielding may include x-ray attenuating particles of different materials, such as copper and tungsten. The particles of x-ray attenuating material may be used in combination with layers of x-ray attenuating material to form plates (such as the plates shown in Figures 3(a) and 3(b)).

[0047] A shielding apparatus 301 ( FIG. 7 ) according to an embodiment of the present disclosure may be used when it is anticipated that X-rays may be used to image a safety device 303. As shown in FIG. 7 , X-rays may be transmitted from a transmitter 316 in a direction (indicated by arrow 302) toward the device 303. The shielding apparatus 301 includes a shielding body 305, and X-rays from the transmitter 316 impinge on the shielding body 305 before reaching the device 303. The shielding body 305 includes a substrate and a layer 309 of X-ray attenuating material. The layer 309 of X-ray attenuating material varies in thickness across the shielding body 305, resulting in variations in X-ray attenuation across the shielding body 305. Thus, the shielding body 305 introduces noise in a random pattern into the X-rays incident on the shielding body 305. The shielding body does not completely attenuate X-rays, and X-ray radiation with noise introduced by the shielding body 305 therefore impinges on the device 303. X-rays that pass through both the shielding 305 and the device 303 may be detected by a receiver 318 to form an image 307. The shielding 305 introduces noise into the x-rays, resulting in an unclear image 307 of the device 303.

[0048] Shielding devices of embodiments of the present disclosure (FIG. 8) may include a shielding body 405 that includes portions with non-random variations in thickness. When attempting to image a device using x-rays, such a shielding body 405 may result in an encoded message in the image. The shielding body 405 includes a layer 409 of x-ray attenuating material. Portions of the x-ray attenuating layer 409 have thicknesses that vary randomly across the shielding body 405. Portions of the x-ray attenuating material 409 have non-random variations in thickness that form letters 410. When x-ray radiation is incident on the shielding body 405 and the radiation is later used to form an image, the encoded message may be introduced into the image.

[0049] According to an embodiment of the present disclosure (FIG. 9), shielding apparatus 501 includes a shield 505 forming a lid for a box and a device 503 placed within the box. Shielding 505 includes a layer of X-ray attenuating material 509. When attempting to image the device using X-rays in the direction indicated by arrow 502 toward the device, the shielding introduces a pattern of noise into the X-rays, which obscures the resulting image.

[0050] According to an embodiment of the present disclosure (FIG. 10), shielding device 601 includes a box-shaped shield 605. Box 605 encloses missile 603. A layer 609 of X-ray attenuating material is applied to each surface of box 605. When X-rays are incident on box 605 from all angles, X-ray attenuating material 609 introduces a pattern of noise into the X-rays.

[0051] According to an exemplary embodiment of the present disclosure (FIG. 11), a shielding apparatus 1101 includes a briefcase-shaped shield 1105. Briefcase 1105 houses device 1103 in the form of a secret prototype. The prototype includes iron features having dimensions between 0.1 mm and 30 mm. An X-ray attenuating layer 1109 is contained within the lining of briefcase 1105. X-ray attenuating layer 1109 includes a plurality of particles (not shown) of X-ray attenuating particles having dimensions between 0.005 mm and 5 mm. The particles are particles of different materials: some particles are tungsten, some are lead, some are polymeric, and some are ceramic. The particles are suspended in a barium-loaded resin binder. The resin binder does not significantly attenuate X-rays. The resin binder and suspended particles are arranged to form pixel arrays within the lining of briefcase 1105. The pixel columns have widths between 5 mm and 50 mm and heights between 5 mm and 30 mm. When X-rays are incident on briefcase 1105 from all angles, the X-ray attenuating material in the lining of briefcase 1105 introduces a pattern of noise into the X-rays. X-rays incident on briefcase 1105 can have energies between approximately 40 keV and 300 keV.

[0052] In other embodiments (not shown), the x-ray attenuating layer may be contained within a dedicated area of ​​the briefcase rather than within the liner.

[0053] According to an exemplary embodiment of the present disclosure (FIG. 12), shielding apparatus 1201 is shielding body 1205 in the form of a safe. Device 1203 in the form of a laptop is housed within safe 1205. Safe 1205 has an interior volume of 30 cm in height, 40 cm in depth, and 40 cm in width. Safe 1205 is designed to shield laptop 1203 from X-rays having energies of approximately 400-400 keV. Laptop 1203 includes features that create a first span of attenuation. The features have dimensions of approximately 0.05-50 mm and have attenuation similar to 10 mm of copper. Safe 1205 includes a layer 1209 of X-ray attenuating material in the form of multiple copper pixel columns distributed across the surface of the safe. The columns have heights ranging from 0 mm to 20 mm. When X-rays are incident on safe 1205, the copper pixels introduce a pattern of noise into the X-rays.

[0054] In another exemplary embodiment (not shown), in addition to or instead of the copper pixels, the surface of the safe includes particles of X-ray attenuating material suspended in a substrate or provided within the box to provide additional shielding.

[0055] According to an exemplary embodiment of the present disclosure (not shown), the shielding apparatus is a shipping container housing a vehicle with an engine. The shielding is a safety panel forming part of the container. The device to be shielded is the vehicle's engine. The engine includes features having a geometry between 5 and 50 mm. The engine has attenuation similar to that of 200 mm of iron. When attempting to image the shipping container using x-rays, x-ray energies between 40 keV and 8 MeV may be used. The safety panel includes a layer of x-ray attenuating material including a plurality of column pixels. The column pixels have a height range between 2.5 mm and 100 mm, and the column pixels include iron. The top surface of each column pixel is textured to provide additional x-ray attenuation. The pixel height variations vary randomly across the safety panel.

[0056] In another exemplary embodiment (not shown), the shielding device is a shipping container and the shielding is a safety panel forming part of the container. The safety panel includes a plurality of X-ray attenuating particles. The particles are iron particles having diameters between 2.5 mm and 10 mm. The particles have varying cross-sections, as well as shapes and sizes. When attempting to image the contents of the container using X-rays and directing the X-rays through the safety panel, the particles introduce a pattern of noise into the X-rays.

[0057] According to an exemplary embodiment of the present disclosure (not shown), a shielding apparatus includes a device in the form of an electronic circuit board. The circuit board includes a plurality of electronic components, such as a silicon component having a width of approximately 5 mm and a trace having a width of approximately 20 μm. The circuit board includes a copper layer having a thickness of 0.5 mm. The shielding body includes a panel including a layer of X-ray attenuating material. The layer includes a plurality of pixel columns. The pixel columns have a thickness in the range of 0.1 to 1 mm and are square in cross-section. The panel is screwed onto the circuit board. The panel shields the circuit board from X-rays having energies between 40 keV and 100 keV.

[0058] According to an embodiment of the present disclosure (not shown), a shielding device includes a shielding body that includes both a plurality of X-ray attenuating particles suspended in a substrate that produces variations in X-ray attenuation across the shielding body, and a plurality of pixelated columns of X-ray attenuating material of varying thickness that additionally produces additional variations in X-ray attenuation across the shielding body. Such a shielding body may be used to shield electronic circuit boards. The pixelated columns may be used to shield silicon components of the circuit, and the particles of X-ray attenuating material suspended in the substrate may be used to shield circuit wires.

[0059] According to an embodiment of the present disclosure (not shown), the shielding apparatus includes a stack of circuit boards (devices) stacked on top of each other within a shielding case having dimensions of approximately 50 cm x 50 cm in area and 20 cm in depth.

[0060] An embodiment of the present disclosure (FIG. 13) provides a method 1301 for producing a shielding device. The shielding device includes a device and a shielding body, where the device attenuates X-rays by different amounts in different portions of the device, providing a first span of attenuation. The shielding body includes a layer of X-ray attenuating material that attenuates X-rays by a varying amount across the shielding body, providing a second span of X-ray attenuation. In a first step 1303, the method includes generating a variation in attenuation across the layer of X-ray attenuating material such that the second attenuation span has a magnitude between 20% and 120% of the first attenuation span. In a second step 1305, the method includes adding a layer of X-ray attenuating material to the shielding body. In a third step 1307, the method includes positioning the shielding body relative to the device such that if X-rays are to be used to image the device, the shielding body will block X-rays used to image the device.

[0061] While the present disclosure has been described and illustrated with reference to specific embodiments, those skilled in the art will recognize that the present disclosure is susceptible to many different variations not specifically exemplified herein. In the foregoing description, integers or elements having known, obvious, or reasonably foreseeable equivalents are set forth; such equivalents are then incorporated herein as if individually set forth. Reference should be made to the claims to determine the true scope of the present disclosure, which should be interpreted to encompass all such equivalents. The reader will recognize that integers or features of the present disclosure described as preferred, advantageous, convenient, etc. are optional and do not limit the scope of the independent claims. Moreover, it should be understood that while such optional integers and features may be advantageous in some embodiments of the present disclosure, they may be undesirable and therefore may not be present in other embodiments.

Claims

1. a device that attenuates x-rays by different amounts in different portions of the device, providing a first span of x-ray attenuation; a shield including a layer of x-ray attenuating material that attenuates x-rays by an amount that varies across the shield, providing a second span of attenuation, the second span of attenuation having a magnitude that is between 20% and 120% of the magnitude of the first span of attenuation; Including, A shielding device wherein the layer of x-ray attenuating material has a thickness that varies across the shield, whereby the x-ray attenuation varies randomly across the shield.

2. The shielding device of claim 1 , wherein the second span of attenuation has a minimum attenuation within the first span of attenuation.

3. 3. The shielding device of claim 1 or 2, wherein the second span of attenuation has a minimum attenuation that is up to twice the maximum attenuation in the first span of attenuation.

4. 3. A shielding arrangement according to claim 1 or 2, wherein the variation in attenuation across the shield is of the same or similar magnitude to the variation in attenuation across the device.

5. 3. The shielding device of claim 1, wherein the attenuation of the x-ray attenuating material varies randomly across the shield.

6. 3. The shielding device of claim 1, wherein the attenuation of the x-ray attenuating material varies randomly across a portion of the shield.

7. 7. The shielding device of claim 6, wherein portions of the shielding have non-random variations in x-ray attenuation that produce an encoded message in an image formed by x-rays passing through the shielding.

8. 3. The shielding device of claim 1, wherein the variation in thickness of the X-ray attenuating material is a stepwise variation in thickness.

9. 3. The shielding device of claim 1, wherein the layer of x-ray attenuating material comprises a continuous layer.

10. 3. A shielding device according to claim 1 or 2, wherein the layer of X-ray attenuating material comprises a coating applied to a substrate.

11. 3. A shielding device according to claim 1 or 2, wherein the shielding comprises regions of X-ray attenuating material distributed within a substrate material.

12. The shielding device of claim 11 , wherein the shielding comprises a plurality of x-ray attenuating particles distributed within a substrate material.

13. 3. The shielding device of claim 1 or 2, wherein the shielding comprises a plurality of X-ray attenuating particles provided in a box.

14. The shielding device of claim 1 or 2, wherein the shielding body comprises a panel.

15. The shielding device of claim 1 or 2, wherein the shielding body comprises a box, a briefcase, a safe, or a container.

16. 3. The shielding device of claim 1 or 2, wherein the layer of X-ray attenuating material comprises a material selected from the list consisting of titanium, iron, nickel, copper, zinc, barium, tungsten, mercury, lead, bismuth, and uranium.

17. 1. A method of producing a shielding apparatus, the shielding apparatus comprising: a device that attenuates x-rays by different amounts in different portions of the device, providing a first span of x-ray attenuation; and a shielding body including layers of x-ray attenuating material that attenuates x-rays by amounts that vary across the shielding body, providing a second span of x-ray attenuation; generating a random variation in attenuation across the layer of x-ray attenuating material such that the second attenuation span has a magnitude between 20% and 120% of the magnitude of the first attenuation span; adding the layer of x-ray attenuating material to the shield; positioning the shield relative to the device such that, when x-rays are used to image the device, the shield blocks x-rays used to image the device; The method, wherein generating the attenuation variation includes generating a thickness variation across the layer of x-ray attenuating material.

18. 18. The method of claim 17, wherein the variation in attenuation across the layer of x-ray attenuating material is generated using additive layer fabrication.

19. 18. The method of claim 17, wherein the variation in attenuation across the layer of x-ray attenuating material is generated using CNC machining.

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