Electromagnetic interference (EMI) shielding end cap for an EMI shielding housing

Abstract

An enclosure for shielding electromagnetic interference (EMI). The enclosure includes an EMI shielding housing having a plurality of walls and at least one open end, wherein the walls define an internal cavity and wherein an inner surface of at least one wall includes an electrically conductive edge section located at the open end. The enclosure also includes an end cap that is removably attached to the open end, an electrically conductive foil element having a wiper contact and a resilient and electrically conductive EMI gasket located between the end cap and the foil element. The wiper contact and EMI gasket are folded such that the wiper contact is located between the EMI gasket and the edge section wherein the wiper contact makes electrical contact with the edge section and the EMI gasket is biased to push the wiper contact toward the edge section to maintain electrical contact.

Description

ELECTROMAGNETIC INTERFERENCE (EMI) SHIELDING END CAP FOR AN EMI SHIELDING HOUSINGTECHNICAL FIELD

[0001] Aspects of the present invention relate to an enclosure for shielding electromagnetic interference (EMI), and more particularly, to an enclosure that includes an EMI shielding housing, at least one end cap, an electrically conductive foil element having a wiper contact and a resilient and electrically conductive EMI gasket located between the end cap and the foil element wherein the wiper contact and EMI gasket are folded such that the wiper contact is located between the EMI gasket and a housing edge section wherein the wiper contact makes electrical contact with the edge section and the EMI gasket is biased to push the wiper contact toward the edge section to maintain electrical contact.BACKGROUND

[0002] A magnetic resonance / positron emission tomography (MR / PET) imaging system is a hybrid diagnostic system that includes two different imaging modalities. The integration of MR and PET imaging systems requires the location of PET detectors within a magnetic resonance imaging (MRI) system volume. Available space within an integrated MR / PET system comes at a premium of both cost and performance, with components often competing for an optimal location. A radio-frequency (RF) system of the MRI system and PET system components require electromagnetic shielding to shield or protect against electromagnetic interference (EMI) generated during operation of the MR / PET imaging system. PET system components, such as PET detectors having silicon photomultipliers (SiPMs), scintillator crystals based on lutetium oxyorthosilicate (LSO), and associated detector electronics assemblies (DEAs) may be located in an enclosure that shields against electromagnetic interference (EMI enclosure).

[0003] The EMI enclosure includes a resealable opening or break in the enclosure to provide periodic access to electronic components located within the enclosure. Current sealing configurations use a combination of gasketing, copper plating on plastics, and adhesive backed foils to seal the EMI enclosure. It has been found that such sealing configurations areunreliable, costly, and may have undesirable side effects due in part to large continuous metallic surfaces that are constructed when building the shield. Such metallic surfaces allow for the development of eddy currents which in turn may lead to undesirable heating, vibrations and ghosting artifacts in images generated by the MR / PET system. It is desirable that the technique used to reseal or close the opening is both repeatable and reliable and provide the same EMI shielding effect as the remaining portions of the enclosure.SUMMARY OF THE INVENTION

[0004] An enclosure for shielding electromagnetic interference (EMI) is disclosed. The enclosure includes an EMI shielding housing having a plurality of walls and at least one open end, wherein the walls define an internal cavity and wherein an inner surface of at least one wall includes an electrically conductive edge section located at the open end. The enclosure also includes an end cap that is removably attached to the open end, an electrically conductive foil element having a wiper contact and a resilient and electrically conductive EMI gasket located between the end cap and the foil element. The wiper contact and EMI gasket are folded such that the wiper contact is located between the EMI gasket and the edge section wherein the wiper contact makes electrical contact with the edge section and the EMI gasket is biased to push the wiper contact toward the edge section to maintain electrical contact.

[0005] In addition, a method for shielding an enclosure from electromagnetic interference (EMI) is disclosed. The method includes providing an EMI shielding housing having a plurality of walls and at least one open end, wherein the walls define an internal cavity and the open end includes an end surface. The method also includes providing an electrically conductive edge section at the open end and on an inner surface of at least one wall and an end cap removably attached to the open end, wherein the end cap includes a flange. In addition, the method includes providing an electrically conductive foil element having a wiper contact and a resilient EMI gasket that is electrically conductive and located between the end cap and the foil element, wherein the foil element makes electrical contact with the EMI gasket. Further, the method includes inserting the end cap into the open end wherein contact between the wiper contact and the end surface causes folding of the wiper contact and EMI gasket such that the wiper contact is located between the EMI gasket and the edge section wherein the wiper contact makes electrical contact with the edge section to provide EMI shielding and the EMIgasket is biased to push the wiper contact toward the edge section to maintain electrical contact.

[0006] Those skilled in the art may apply the respective features of the present invention jointly or severally in any combination or sub-combination.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The exemplary embodiments of the invention are further described in the following detailed description in conjunction with the accompanying drawings, in which:

[0008] Fig. 1 depicts a housing that provides electromagnetic interference (EMI) shielding for PET imaging system components.

[0009] Fig. 2 is an enlarged view of a first end of the EMI housing without a first end cap to depict a first open end.

[0010] Fig. 3 is an enlarged view of the first end of the EMI housing shown in Fig. 1.

[0011] Fig. 4 is a partial cross-sectional view of a first embodiment of first and second end caps shown in exploded (left) and assembled (right) views.

[0012] Fig. 5 is view of the first end cap of the first embodiment along view line 5-5 of Fig. 4

[0013] Fig. 6 is a partial cross-sectional view of a second embodiment of the first and second end caps shown in exploded (left) and assembled (right) views.

[0014] Fig. 7 is a partial cross-sectional view of a third embodiment of the first and second end caps shown in exploded (left) and assembled (right) views.

[0015] Fig. 8 is a partial cross-section top view of the EMI housing and the first end cap of the third embodiment.

[0016] Fig. 9 is a perspective view of a power cable shown in Fig. 8.

[0017] Fig. 10 is an exploded view of an exemplary first end of the EMI housing.

[0018] Fig. 11 is a front view of a magnetic resonance / positron emission tomography (MR / PET) imaging system.DETAILED DESCRIPTION

[0019] Although various embodiments that incorporate the teachings of the present disclosure have been shown and described in detail herein, those skilled in the art can readily devise many other varied embodiments that still incorporate these teachings. The scope of the disclosure is not limited in its application to the exemplary embodiment details of construction and the arrangement of components set forth in the description or illustrated in the drawings. The disclosure encompasses other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings.

[0020] The current invention is applicable to any electromagnetic interference (EMI) shielding enclosure such an EMI shielding enclosure used in a magnetic resonance / positron emission tomography (MR / PET) imaging system. Referring to Fig. 1, a housing 10 that provides EMI shielding (EMI housing 10) for PET imaging system components is shown. The EMI housing 10 is fabricated from at least one electrically conductive material to provide shielding against EMI such as carbon fiber although other materials or a combination of materials may be used. The EMI housing 10 is also shaped and sized to provide EMI shielding properties. The EMI housing 10 extends along a longitudinal axis 12 and includes first 14 and second 16 ends having first 18 and second 20 EMI shielding end caps, respectively. Referringto Fig. 2, an enlarged view of the first end 14 of the EMI housing 10 is show n without the first end cap 18 to depict a first open end 15. In an embodiment, the EMI housing 10 includes upper 22 and lower 24 walls and transverse left 26 and right 28 side walls to form a substantially rectangular shaped cross-section which define an internal cavity 30. The upper 22, lower 24, left 26 and right 28 side walls terminate at first 58 and second 60 end surfaces at the first 14 and second 16 ends, respectively, that are oriented transverse to the longitudinal axis 12. Inner surfaces 32 of the upper 22, lower 24, left 26 and right 28 side walls include a first edge section 34 located at the first open end 15 that includes an electrically conductive material 36 to enhance electrical conductivity such as an embedded metal strip or insert. Alternatively, the first edge section 34 may be painted with metal paint or sanded to expose carbon fibers. A second edge section 38 located at a second open end 40 of the EMI housing 10 is prepared similarly to the first edge section 34 to include an electrically conductive material, metal paint or the second edge section 38 is sanded. In an embodiment, the EMI housing 10 may serve as a wave guide when the length of the EMI housing 10 is at least three times greater than the longest side wall 22, 24, 26, 28 of the rectangular cross-section, no conductors or metallic structures pass through or reside within the EMI housing 10 and electronics within the EMI housing 10 are not located in a designated wave guide region. Further, the EMI housing 10 may be configured in other cross-sectional shapes that provide EMI shielding.

[0021] In accordance with an aspect of the invention, the first 15 and second 40 open ends of the EMI housing 10 are closed or sealed by the first 18 and second 20 end caps, respectively, to form an enclosure 42 that shields against EMI (EMI enclosure 42). Alternatively, EMI enclosure 42 may have only one open end that is sealed by an associated end cap such as the first open end 15 that is sealed by the first end cap 18. In Fig. 1, the walls 22. 24. 26, 28 of the EMI enclosure 42 are shown transparent for purposes of illustration. Various PET system components 42, such as PET detectors having silicon photomultipliers (SiPMs), scintillator crystals based on lutetium oxyorthosilicate (LSO), and associated detector electronics assemblies (DEAs) are located in the cavity 30 of the EMI enclosure 42. The end caps 18, 20 may either be solid, i.e., with no penetrations, or may include one or more feed-through nonconductor penetrations along with associated wave guides for attenuating radio-frequency (RF) energy. Referring to Fig. 1, the first end cap 18 is depicted with a plurality of nonconductor penetrations 46 and associated w ave guides 48 and the second end cap 20 is shown solid. Fig. 3 is an enlarged view of the first end 14 of the EMI housing 10 shown inFig. 1. Each nonconductor penetration 46 extends through an associated wave guide 48 formed in the first end cap 18 and penetrates the first end cap 18. For example, each nonconductor penetration 46 may include a nonconducting element used in connection with PET system components 44 such as a water tube for supplying cooling water, optical fiber for enabling fiber optic communications or other nonconducting element.

[0022] In the following description, three embodiments of the first 18 and second 20 end caps will be described. Each embodiment is applicable to either solid end caps or end caps that have nonconductor penetrations. For purposes of clarity, nonconductor penetrations and PET system components are not shown. Referring to Fig. 4, a partial cross-sectional view of a first embodiment of the first 50 and second 52 end caps are show n in exploded (left) and assembled (right) views. The first 50 and second 52 end caps include first 54 and second 56 outer flanges that abut against the first 58 and second 60 end surfaces, respectively, of the EMI housing 10. In addition, first 62 and second 64 carrier elements are attached to the first 50 and second 52 end caps, respectively, as will be described.

[0023] The following description of the first embodiment refers to the first end cap 50 but it is understood that the description of the first end cap 50 is also applicable to the second end cap 52. Fig. 5 is view of the first end cap along view line 5-5 of Fig. 4. Referring to Figs. 4 and 5, the first end cap 50 includes first 66 and second 68 stepped portions. The first outer flange 54 and first 66 and second 68 stepped portions each having a substantially rectangular shape or alternatively, other cross sectional shapes such as a half circle may be used. The first stepped portion 66 is sized smaller than the first outer flange 54 and is sized to fit adjacent inner surfaces 32 of the upper 22, lower 24, left 26 and right 28 side walls of the EMI housing 10 (see Fig. 2). The second stepped portion 68 is sized smaller than the first stepped portion 66 and includes an end cap contact surface 70. The second stepped portion 68 includes an electrically conductive EMI shielding gasket 72 having a substantially round cross-sectional shape (see Fig. 4) or alternatively, a square or other cross-sectional shape may be used. The EMI gasket 72 extends along a perimeter of the second stepped portion 68 to form a substantially rectangular shape (see Fig. 5). Referring back to Fig. 4, an electrically conductive printed circuit board 74 (PCB 74) having exposed metal surfaces is located between the first carrier 62 and the end cap contact surface 70 and EMI gasket 72. An end cap fastener 76 penetrates through the first end cap 50, an electrically conductive EMI shielding washer 78,the PCB 74 and is threaded within a threaded insert 80 installed in the first carrier 62 to removably attach the first end cap 50 to the first carrier 62. The EMI washer 78 is fabricated from an electrically conductive material and electrically contacts the PCB 74 and threads 82 of the end cap fastener 76. In an embodiment, the EMI washer 78 is fabricated from a resilient material that forms around the threads 82 to make electrical contact with the end cap fastener 76 to provide EMI shielding. In accordance with an aspect of the invention, the EMI washer 78 is fabricated from an electrically conductive felt material. It is understood that more than one end cap fastener 76 and associated EMI washer 78 and insert may be used to removably attach the first end cap 50 to the first carrier 62.

[0024] The second stepped portion 68 and the EMI gasket 72 are sized such that the EMI gasket 72 is compressed between the PCB 74 and the first 66 and second 68 stepped portions and first edge sect on 34, for example, of the EMI housing 10 upon insertion of the assembled first end cap 50 and first carrier 62 into the first open end 15. In accordance with an aspect of the invention, the EMI washer 78, PCB 74 and EMI gasket 72 are in electrical contact with the first edge section 34 to provide EMI shielding. Similarly, the EMI washer 78, PCB 74. EMI gasket 72 of the second end cap 52 are in electrical contact with the second edge section 38 to provide EMI shielding upon insertion of the assembled second end cap 52 and second carrier 64 into the second open end 40.

[0025] A crossbar 84 extends from the first carrier 62 and through the cavity 30 of the EMI housing 10 to the second carrier 64. The crossbar 84 may be removably attached to the first 62 and second 64 carriers by, for example, respective crossbar fasteners 86 to form a mechanical connection between the first 50 and second 52 end caps. In order to assemble the crossbar 84 to the EMI housing 10, the cross bar 84 is first attached to the first 62 and second 64 carriers by the respective cross bar fasteners 86. An end cap, for example the first end cap 50, is then attached to the first carrier 62 by an end cap fastener 76. The cross bar 84 is inserted into the first open end 15 until the first outer flange 54 contacts the first end surface 58. The second end cap 52 is then attached to the second carrier 64 by an end cap fastener 76 and is tightened. This tensions the cross bar 84 between the first and second end caps to cause the first 54 and second 56 outer flanges of the first 50 and second 52 end caps to abut against the first 58 and second 60 end surfaces, respectively, of the EMI housing 10 and remain in place relative to the EMI housing 10. In this configuration, the cross bar 84 is a cooling structure.In an embodiment, the end caps 50,52 and carriers 62, 64 may be fabricated from a polymer material.

[0026] Referring to Fig. 6, partial cross-sectional views of a second embodiment of the first 88 and second 90 end caps are shown in exploded (left) and assembled (right) views. The following description of the second embodiment refers to the first end cap 88 but it is understood that the description of the first end cap 88 is also applicable to the second end cap 90.

[0027] The first end cap 88 includes the first stepped portion 66, the end cap contact surface 70 and a tapered surface 92 in place of the second stepped portion 68 shown in Fig. 4. An electrically conductive flat EMI shielding gasket 94 is located between the end cap contact surface 70 and an electrically conductive flexible element such as a rigid flex PCB 96 having exposed metal surfaces. The rigid flex PCB 96 includes a flat base portion 98 that is smaller than the EMI gasket 94 and an electrically conductive contact element 100 that extends from the base portion 98. The contact element 100 is oriented toward the EMI gasket 94 and is flexible. An end cap fastener 76 penetrates through the first end cap 88, EMI gasket 94, rigid flex PCB 96 and is threaded within the insert 80 to removably attach the first end cap 88 to the first carrier 62. Upon fastening of the end cap fastener 76 to the first carrier 62, the contact surface 70. EMI gasket 94, rigid flex PCB 96 and first carrier 62 are in contact. The EMI gasket 94 electrically contacts the rigid flex PCB 96 and threads 82 of the end cap fastener 76. In an embodiment, the EMI gasket 94 is fabricated from a resilient material that forms around the threads 82 to make electrical contact with the end cap fastener 76 to provide EMI shielding. In accordance with an aspect of the invention, the EMI gasket 94 is fabricated from an electrically conductive felt material. It is understood that more than one end cap fastener 76 may be used to removably attach the first end cap 88 to the first carrier 62.

[0028] Upon insertion of the assembled first end cap 88 and first carrier 62 into the first open end 15. the contact element 100 moves toward the first end surface 58 and contacts the first end surface 58. This causes folding of the contact element 100 toward the EMI gasket 94. The contact element 100 then contacts the EMI gasket 94 which causes folding of both the contact element 100 and EMI gasket 94 toward the tapered surface 92. The contact element 100 and EMI gasket 94 then contact the tapered surface 92 such that the contact element 100 and EMIgasket 94 conform to the shape of the tapered surface 92 and the contact element 100 is located between the EMI gasket 94 and the first edge section 34. Insertion of the first end cap 88 stops when the first outer flange 54 abuts against the first end surface 58. When this occurs, the contact element 100 is oriented at an angle corresponding to the tapered surface 92 such that contact element 100 contacts the first edge section 34. Thus, the EMI gasket 94, rigid flex PCB 96 and contact element 100 are in electrical contact with the first edge section 34 to provide EMI shielding. In addition, the resilient properties of the EMI gasket 94 serve to push or bias the contact element 100 toward the first edge section 34 to maintain contact between the contact element 100 and the first edge section 34. Similarly, the EMI gasket 94, rigid flex PCB 96 and contact element 100 of the second end cap 90 are in electrical contact with the second edge section 38 to provide EMI shielding upon insertion of the assembled second end cap 90 and second earner 64 into the second open end 40.

[0029] The second embodiment of the first 88 and second 90 end caps also includes the crossbar 84. Similar to the first embodiment, the cross bar 84 is first attached to the first 62 and second 64 carriers by the respective cross bar fasteners 86. An end cap, for example the first end cap 88, is then attached to the first carrier 62 by an end cap fastener 76. The cross bar 84 is inserted into the first open end 15 until the first outer flange 54 contacts the first end surface 58. The second end cap 90 is then attached to the second carrier 64 by an end cap fastener 76 and is tightened. This tensions the cross bar 84 between the first 88 and second 90 end caps to cause the first 54 and second 56 flanges of the first 88 and second 90 end caps to abut against the first 58 and second 60 end surfaces, respectively, of the EMI housing 10 and remain in place relative to the EMI housing 10. In this configuration, the cross bar 84 is a cooling structure.

[0030] Referring to Fig. 7, partial cross-sectional views of a third embodiment of the first 102 and second 104 end caps are shown in exploded (left) and assembled (right) views. The following description of the third embodiment refers to the first end cap 102 but it is understood that the description of the first end cap 102 is also applicable to the second end cap 104.

[0031] The first end cap 102 includes the first stepped portion 66, the end cap contact surface 70 and the tapered surface 92. In the third embodiment, a foil element 106 fabricated from an electrically conductive material is substituted for the rigid flex PCB 96. In an embodiment, thefoil element 106 is fabricated from copper. The foil element 106 includes a flat base portion 108 that is smaller than the EMI gasket 94 and an electrically conductive wiper contact element 110 that extends from the base portion 108. The wiper contact 110 is oriented toward the EMI gasket 94 and is flexible. An end cap fastener 76 penetrates through the first end cap 102, EMI gasket 94, foil element 106 and is threaded within the insert 80 to removably attach the first end cap 102 to the first carrier 62. Upon fastening of the end cap fastener 76 to the first carrier 62. the contact surface 70. EMI gasket 94, foil element 106 and first carrier 62 are in contact. The EMI gasket 94 electrically contacts the foil element 106 and threads 82 of the end cap fastener 76. As previously described, the EMI gasket 94 is electrically conductive and is fabricated from a resilient material, such as felt, that forms around the threads 82 to make electrical contact with the end cap fastener 76 to provide EMI shielding. It is understood that more than one end cap fastener 76 may be used to removably attach the first end cap 102 to the first carrier 62.

[0032] Upon insertion of the assembled first end cap 102 and first carrier 62 into the first open end 15. the wiper contact 110 moves toward the first ends surface 58 and contacts the first end surface 58. This causes folding of the wiper contact 110 toward the EMI gasket 94. The wiper contact 110 then contacts the EMI gasket 94 which causes folding of both the wiper contact 110 and EMI gasket 94 toward the tapered surface 92. The contact element 100 and EMI gasket 94 then contact the tapered surface 92 such that the wiper contact 110 and EMI gasket 94 conform to the shape of the tapered surface 92 and the wiper contact 110 is located between the EMI gasket 94 and the first edge section 34. Insertion of the first end cap 102 stops when the first outer flange 54 abuts against the first end surface 58. When this occurs, the wiper contact 110 is oriented at an angle corresponding to the tapered surface 92 such that wiper contact 110 contacts the first edge section 34. Thus, the EMI gasket 94. foil element 106 and wiper contact 110 are in electrical contact with the first edge section 34 to provide EMI shielding. In addition, the resilient properties of the EMI gasket 94 serve to push or bias the wiper contact 110 toward the first edge section 34 to maintain electrical contact between the wiper contact 110 and the first edge section 34. Similarly, the EMI gasket 94. foil element 106 and wiper contact 110 of the second end cap 104 are in electrical contact with the second edge section 38 to provide EMI shielding upon insertion of the assembled second end cap 104 and second carrier 64 into the second open end 40.

[0033] The third embodiment of the first 102 and second 104 end caps also includes the crossbar 84. Similar to the first embodiment, the cross bar 84 is first attached to the first 62 and second 64 carriers by the respective cross bar fasteners 86. An end cap, for example the first end cap 102, is then attached to the first carrier 62 by an end cap fastener 76. The cross bar 84 is inserted into the first open end 15 until the first outer flange 54 contacts the first end surface 58. The second end cap 104 is then attached to the second carrier 64 by an end cap fastener 76 and is tightened. This tensions the cross bar 84 between the first 102 and second 104 end caps to cause the first 54 and second 56 flanges of the first 102 and second 104 end caps to abut against the first 58 and second 60 end surfaces, respectively, of the EMI housing 10 and remain in place relative to the EMI housing 10. In this configuration, the cross bar 84 is a cooling structure.

[0034] Referring to Fig. 8, a partial cross-section top view of the EMI housing 10 and the first end cap 102 of the third embodiment is shown. The EMI housing 10 includes a hollow circular tube 112 having tapered mounting portions 114 and a power cable 116 that includes a cable braid 118. The tube 112 serves as a wave guide 112 when the length of the tube 112 is at least three times greater than the effective diameter of tube 112 and no conductors or metallic structures pass through or reside within the tube 112. Fig. 9 is a perspective view of the power cable 116 shown in Fig. 8. At least one conductor 120 extends through the cable braid 118 of the power cable 116. A grounding flange 122 that extends in a transverse direction relative to the longitudinal axis 12 is formed on the cable braid 1 18.

[0035] Fig. 9 is an exploded view of an exemplary first end of the EMI housing 10. Referring to Figs. 7, 8 and 9. the tapered portions 114 of the wave guide 112 and the grounding flange 122 of the cable braid 118 are located between the EMI gasket 94 and foil element 106 of the third embodiment of the first end cap 102. Upon assembly of the first end cap 102 to the first carrier 62, the tapered portions 114 and grounding flange 122 are compressed between the EMI gasket 94 and foil element 106 and in electrical contact, thus grounding the wave guide 112 and power cable 116. Alternatively, the second embodiment of the first end cap 88 may be used to ground the wave guide 112 and power cable 116 by compressing the tapered portions 114 and grounding flange 122 between the EMI gasket 94 and the rigid flex PCB 96.

[0036] The current invention is applicable to any EMI shielding enclosure such an EMI shielding enclosure used in an MR / PET imaging system. Referring to Fig. 11, a front view of an MR / PET imaging system 124 is shown that depicts at least one EMI enclosure 42 of the invention. The system 124 includes a patient bore 126 or tunnel that receives a patient to be scanned, a body coil 128 (component of the MRI system), PET gantry 130 (part of the PET system) that includes at least one EMI enclosure 42 arranged longitudinally about the longitudinal axis 12, gradient coil 132 (a component of the MRI system) and superconducting magnet 134 (a component of the MRI system).

[0037] While particular embodiments of the present disclosure have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the disclosure. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this disclosure.

Claims

CLAIMSWe claim:

1. An enclosure for shielding electromagnetic interference (EMI), the enclosure comprising: an EMI shielding housing having a plurality of walls and at least one open end, wherein the w alls define an internal cavity and wherein an inner surface of at least one wall includes an electrically conductive edge section located at the open end; an end cap removably attached to the open end; an electrically conductive foil element having a wiper contact; a resilient EMI gasket that is electrically conductive and located between the end cap and the foil element, w herein the foil element makes electrical contact with the EMI gasket and wherein the wiper contact and EMI gasket are folded such that the wiper contact is located between the EMI gasket and the edge section wherein the wiper contact makes electrical contact with the edge section to provide EMI shielding and the EMI gasket is biased to push the wiper contact toward the edge section to maintain electrical contact.

2. The enclosure according to claim 1, further including a carrier element wherein a fastener extends through the end cap, EMI gasket, foil element and carrier element to removably attach the end cap to the carrier element w herein the EMI gasket forms around the fastener to electrically contact the fastener to provide EMI shielding.

3. The enclosure according to claim 1. wherein the EMI housing is fabricated from carbon fiber and electrical conductivity of the edge section is enhanced by attaching a metal strip to the edge section, painting the edge section with metal paint or sanding the edge section to expose carbon fibers of the EMI housing.

4. The enclosure according to claim 1. further including at least one wave guide having tapered mounting portions w herein the mounting portions are located between the EMI gasket and foil element.

5. The enclosure according to claim 4, wherein a length of the wave guide is at least three times greater than the effective diameter of the wave guide.

6. The enclosure according to claim 1, wherein a power cable having a cable braid penetrates the end cap wherein a grounding flange is formed on the cable braid and is located between the EMI gasket and foil element.

7. An enclosure for shielding electromagnetic interference (EMI) in a magnetic resonance / positron emission tomography (MR / PET) imaging system, the enclosure comprising: an EMI shielding housing having a plurality of walls that terminate at first and second end surfaces to define first and second open ends, respectively, wherein the walls also define an internal cavity and wherein an inner surface of at least one wall includes electrically conductive first and second edge sections located at the first and second open ends, respectively; first and second end caps having first and second outer flanges, respectively, the first and second end caps including first and second electrically conductive foil elements having first and second wiper contacts and first and second resilient EMI gaskets that are electrically conductive and located between the first and second end caps and the first and second foil elements, respectively, wherein the first and second foil elements make electrical contact with the first and second EMI gaskets, respectively, and wherein the first and second wiper contacts and first and second EMI gaskets are folded, respectively, such that the first and second wiper contacts are located between the first and second EMI gaskets and the first and second edge sections, respectively, wherein the first and second wiper contacts make electrical contact with the first and second edge sections, respectively, to provide EMI shielding and wherein the first and second EMI gaskets are biased to push the first and second wiper contacts toward the first and second edge sections, respectively, to maintain electrical contact; and a crossbar that extends through the EMI housing wherein the crossbar is removably attached between the first and second end caps by respective fasteners, wherein tightening of at least one fastener tensions the crossbar (84) between the first (102) and second (104) end caps such that the first and second outer flanges abut against the first and second end surfaces, respectively, to hold the first and second end caps to the EMI housing.

8. The enclosure according to claim 7, further including first and second carrier elements removably attached to the first and second end caps, respectively, wherein first and second fasteners extend through the first and second end caps, first and second EMI gaskets, first and second foil elements and first and second carriers to removably attach the first and second end caps to the first and second carriers, respectively, wherein the first and second EMI gaskets form around the first and second fasteners to electrically contact the first and second fasteners, respectively, to provide EMI shielding.

9. The enclosure according to claim 7, wherein the EMI housing is fabricated from carbon fiber and electrical conductivity of the first and second edge sections is enhanced by attaching a metal strip to the edge section, painting the edge section with metal paint or sanding the first and second edge sections to expose carbon fibers of the EMI housing.

10. The enclosure according to claim 7, further including at least one wave guide having tapered mounting portions wherein the mounting portions are located between the first EMI gasket and first foil element of the first end cap.

11. The enclosure according to claim 10, wherein a length of the wave guide is at least three times greater than the effective diameter of the wave guide.

12. The enclosure according to claim 7, wherein a power cable having a cable braid penetrates the first end cap wherein a grounding flange formed on the cable braid is located between the first EMI gasket and first foil element.

13. The enclosure according to claim 7, wherein the enclosure includes PET system components.

14. A method for shielding an enclosure from electromagnetic interference (EMI), the method comprising: providing an EMI shielding housing having a plurality of walls and at least one open end, wherein the walls define an internal cavity and the open end includes an end surface; providing an electrically conductive edge section at the open end and on an inner surface of at least one wall;providing an end cap removably atached to the open end, wherein the end cap includes a flange; providing an electrically conductive foil element having a wiper contact; providing a resilient EMI gasket that is electrically conductive and located between the end cap and the foil element, wherein the foil element makes electrical contact wi th the EMI gasket; and inserting the end cap into the open end wherein contact between the wiper contact and the end surface causes folding of the wiper contact and EMI gasket such that the wiper contact is located between the EMI gasket and the edge section wherein the wiper contact makes electrical contact with the edge section to provide EMI shielding and the EMI gasket is biased to push the wiper contact toward the edge section to maintain electrical contact.

15. The method according to claim 14, further including providing a carrier element wherein a fastener extends through the end cap, EMI gasket, foil element and carrier element to removably atach the end cap to the carrier element.

16. The method according to claim 15, further including forming the EMI gasket around the fastener to electrically contact the fastener to provide EMI shielding.

17. The method according to claim 14, wherein the EMI housing is fabricated from carbon fiber and further including attaching a metal strip to the edge section, painting the edge section with metal paint or sanding the edge section to expose carbon fibers of the EMI housing to enhance electrical conductivity7of the edge section.

18. The method according to claim 14. further including providing at least one wave guide having tapered mounting portions wherein the mounting portions are located between the EMI gasket and foil element.

19. The method according to claim 18, wherein a length of the wave guide is at least three times greater than the effective diameter of the wave guide.

20. The method according to claim 14, further including providing a power cable having a cable braid that penetrates the end cap wherein a grounding flange is formed on the cable braid and is located between the EMI gasket and foil element.

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