Abstract:
An apparatus for supporting UHV modules and attaching accessories thereto without welding and without obstructing any conflat ports includes a bracket attachable to an attachment feature without loss of vacuum. Embodiments permit arbitrary UHV module reorientation. In some embodiments, a supporting circular groove or series of groove segments is provided in the UHV module, and a clamping bracket fitted with holes meeting optical bench standards is attached to the groove by clamping two clamp segments together while fitting a tongue firmly into the groove. The supporting groove can be located in an extension terminating in a conflat flange, or in a separate UHV extender module. In other embodiments, the attachment feature is a plurality of threaded mounting holes that are not associated with conflat ports, do not require enlargement of the UHV module, and permit attachment of brackets without obstructing any conflat ports and without loss of vacuum.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/412,208, filed Nov. 10, 2010 and is herein incorporated by reference in its entirety for all purposes. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates to ultra-high vacuum systems, and more particularly to apparatus and methods for supporting the weight of ultra-high vacuum systems. 
       BACKGROUND OF THE INVENTION 
       [0003]    Ultra-high vacuum systems find wide applications in research, education, product development, and production. Typical systems are comprised of independent and interchangeable ultra-high vacuum (UHV) components or modules, such as testing chambers, pumps, gauges, valves, specimen holders, electron sources, ion sources, photon sources, molecular beam sources, detectors of various types, and such like. 
         [0004]    Processes or experiments that require high or ultra-high vacuum (UHV) currently employ all-metal vacuum joints formed by joining two vacuum ports to each other. A typical all-metal vacuum port, referred to herein as a “conflat” port, such as that described in U.S. Pat. No. 3,208,758, is illustrated in  FIG. 1 . Conflat ports include an annular joining region  20  surrounding an annular recess  26  and an annular knife edge  30 . For some conflat ports, the annular joining region is a “conflat” flange  20  which provides tapped or clearance holes through which bolts can be inserted. Other conflat ports include a joining region with tapped holes bored directly into the body of the UHV module itself, so that the joining region is substantially flush with the body of the UHV module. 
         [0005]      FIGS. 1 and 2  are perspective and cross-sectional side views respectively of an example of a conflat port having a conflat flange  20 . With reference to  FIG. 2 , the conflat flange  20  is shown mated with another, similar flange  24  to form a conflat joint, the two flanges  20 ,  24  being separated by a soft, metallic gasket  34 , which is usually made of copper. The opposing knife edges  30 ,  32  are pressed into the copper gasket  34  by tightening bolts  38 , thereby forming the UHV seal of the conflat joint. 
         [0006]    Many UHV applications require that a plurality of UHV modules be connected together by conflat joints into a single, large UHV system. Some UHV modules are approximately cubical or spherical, while others are more tubular, and may extend over a length which significantly exceeds their diameter. Many UHV modules are heavy, such that their weight must be properly supported so as to avoid applying undue torque to any of the conflat joints and risking a possible leak. 
         [0007]    One typical approach to supporting the weight of UHV modules in a UHV system is to weld support flanges or struts to some of the UHV modules, and then to attach the support flanges or struts to an appropriate supporting platform. However, this requires on-site modification of the UHV modules using special welding equipment and skills, and results in permanent modifications to the UHV modules that cannot be easily removed or adjusted. In particular, such a welding approach typically provides support only at a fixed orientation of a UHV module, and does not allow for rotational adjustment and matching of the orientations of the UHV modules as they are assembled. 
         [0008]    Another typical approach to supporting the weight of UHV modules in a UHV system is to attach support members to unused conflat ports in the system. In this approach, each support member is welded or otherwise permanently attached to a blank conflat flange that can be attached to an otherwise unused conflat port of the UHV module. This approach provides a reversible solution that requires no special equipment, and that can be rotated between a limited number of fixed orientations according to the pattern of bolt holes included in the conflat port. However, this approach necessarily requires that a sufficient number of otherwise unused conflat ports be available for attachment of supporting struts. And once the supports are assembled to the system, they cannot be removed or adjusted without loss of the vacuum within the system, which typically requires a time consuming re-sealing and re-pumping process afterward. 
         [0009]    Yet another approach to supporting the weight of UHV modules in a UHV system is to remove at least one bolt from a conflat joint and attach a mounting strut or bracket to the exterior of the joint by passing a longer bolt or bolts through the strut and through the conflat joint. However, this approach tends to disturb the uniformity of the pressure which compresses the conflat joint and forms the UHV seal, thereby risking a vacuum leak. Also, this approach can cause the strut or bracket to apply a torque to the conflat joint, thereby risking a vacuum leak. 
         [0010]    What is needed, therefore, is an apparatus for supporting the weight of a UHV module in a UHV system, wherein the apparatus does not require on-site modification of the UHV module, does not use, obstruct, or disturb any conflat ports, and enables attachment and detachment of the supporting apparatus, and reorientation of the UHV module about arbitrary angles relative to the supporting apparatus, without loss of vacuum. 
       SUMMARY OF THE INVENTION 
       [0011]    The present invention is an apparatus for supporting the weight of a UHV module in a UHV system without on-site modification of the UHV module, and without using, obstructing, or disturbing any conflat ports. The invention enables attachment and detachment of the supporting apparatus without loss of vacuum. Embodiments also permit reorientation of the UHV module about arbitrary angles relative to the supporting apparatus without loss of vacuum. The apparatus of the present invention includes an attachment feature included in the UHV module at the time of its manufacture, and a bracket that is attachable to the attachment feature without loss of vacuum and without using or blocking any conflat ports. 
         [0012]    In one general aspect of the present invention, the attachment feature is a supporting groove formed in a UHV module in a circular pattern, the groove being compatible with a clamping bracket having a corresponding circular tongue that fits firmly into the groove so as to attach the bracket firmly to the UHV module. In various embodiments, the groove is broken into a series of supporting groove segments. It should be noted that the terms “groove” and “supporting groove” are used generically herein to refer to both a single groove and to a series of aligned groove segments, unless otherwise specified. In some embodiments, an angular orientation of the UHV module can be adjusted over a continuously selectable angle by loosening the attached clamping bracket and rotating the groove (or groove segments) relative to the bracket. 
         [0013]    In some embodiments, the supporting groove surrounds an extension which joins a conflat flange to the body of the UHV module, and in other embodiments the supporting groove is in an adaptor UHV module that attaches to and extends a conflat port of the UHV module, so that there is no reduction in the number of available conflat ports. In various embodiments, the supporting groove is also compatible with brackets which clamp adjoining UHV modules together. 
         [0014]    In certain embodiments, the supporting groove is formed directly in the body of the UHV module, and does not surround an extension or flange, although it may surround a conflat port. 
         [0015]    In another general aspect of the present invention, the attachment feature is a plurality of threaded mounting holes that are not associated with conflat ports, the mounting holes being located so as to permit bolting of brackets to the holes without obstructing any conflat ports, and without loss of vacuum. 
         [0016]    The features and advantages described herein are not all-inclusive and, in particular, many additional features and advantages will be apparent to one of ordinary skill in the art in view of the drawings, specification, and claims. Moreover, it should be noted that the language used in the specification has been principally selected for readability and instructional purposes, and not to limit the scope of the inventive subject matter. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  is a perspective drawing of a conflat flange of the prior art; 
           [0018]      FIG. 2  is a side cross-sectional partial view of a pair of the prior art conflat flanges of  FIG. 1  bolted to each other; 
           [0019]      FIG. 3  is a perspective drawing of a UHV module having two conflat ports that are surrounded by pluralities of support groove segments in an embodiment of the present invention; 
           [0020]      FIG. 4  is a perspective view of an adaptor UHV module that is configured to extend a conflat port, and that includes a plurality of support groove segments, the adaptor module being shown in relation to a clamping bracket of an embodiment of the present invention; 
           [0021]      FIG. 5  is a perspective view of a UHV module having a pair of the adaptor UHV modules attached to opposing conflat ports thereof, the UHV module being supported by a pair of clamping brackets attached to the support groove segments of the adaptor UHV modules, the clamping brackets being bolted to an optical bench; 
           [0022]      FIG. 6A  is a perspective view of a UHV system that includes a plurality of UHV modules joined to each other by conflat joints, the UHV system being supported by a pair of clamping brackets attached to a pair of support grooves, each of which is associated with one of the conflat ports; 
           [0023]      FIG. 6B  is an end view of the system of  FIG. 6A ; 
           [0024]      FIG. 6C  is a side view of the system of  FIG. 6A ; 
           [0025]      FIG. 7A  is a perspective view of a UHV module having a support groove formed in a spherical UHV module in a location which surrounds a conflat port; 
           [0026]      FIG. 7B  is a perspective view of the UHV module of  FIG. 7A  showing a clamping bracket attached to the support groove; 
           [0027]      FIG. 8A  is a detailed front drawing of a clamping bracket similar to the bracket of  FIG. 4 ; 
           [0028]      FIG. 8B  is a detailed side split view drawing of the bracket of  FIG. 8A ; 
           [0029]      FIGS. 8C through 8H  are detailed front and side split view drawings of three other embodiments of clamping brackets; 
           [0030]      FIG. 9  is a perspective view of the UHV module of  FIG. 5 , showing a support bracket attached to mounting holes provided in the top of the UHV module; and 
           [0031]      FIG. 10  is a perspective view of a UHV module formed in the shape of two adjoining spheres, the UHV module having a pair of mounting holes on its side. 
       
    
    
     DETAILED DESCRIPTION 
       [0032]    With reference to  FIG. 3  and  FIG. 4 , the present invention is an apparatus for supporting the weight of a UHV module  300  in a UHV system without on-site modification of the UHV module  300 , and without using or obstructing any conflat ports  302 . The apparatus includes an attachment feature  304  included in the UHV module  300  at the time of its manufacture, and a bracket  400 ,  402  which is attachable to the attachment feature  304  without loss of vacuum and without using or blocking any conflat ports. 
         [0033]    In one general aspect of the present invention, the attachment feature is a groove or a series of groove segments  304  into which tongue features  406  of the mounting bracket  400 ,  402  can be firmly inserted and clamped so as to attach the mounting bracket  400 ,  402  to the UHV module  300 . The UHV module  300  illustrated in  FIG. 3  includes a plurality of conflat ports. One of the conflat ports includes a flange  306  with clearance holes  308  through which mounting bolts can be inserted. An attachment feature proximal to this conflat port is a series of equally spaced, equally sized grooves  304  shaped as arcs aligned about a common circle, whereby the gaps between the arcs provide access for bolts to enter the clearance holes  308 . 
         [0034]    Another conflat port  302  in the UHV module  300  of  FIG. 3  includes tapped holes  36  for threading therein of mounting bolts. An attachment feature proximal to this conflat port  302  is a series grooves  310  shaped as arcs of unequal sizes and unequal spacing aligned about a common circle, whereby the gaps between the segments provide access to additional conflat ports  312  included in the UHV module  300 . 
         [0035]      FIG. 4  illustrates a UHV adaptor module  401  that includes a pair of closely adjacent opposing conflat ports  303 ,  307  separated by a short segment in which are formed a series of supporting grooves segments  304 . The supporting groove segments  304  are separated by gaps that provide space for bolts to enter bolt holes  408  so as to bolt one of the conflat ports  307  of the UHV adaptor module  401  to a conflat port of a UHV module. The other conflat port  303  is then available for attachment of a second UHV module, so that the number of available conflat ports is not reduced by attachment of the UHV adaptor module  401  to the UHV module. 
         [0036]    The adaptor module  401 is shown in  FIG. 4  in relationship to a disassembled clamping bracket formed by a round top segment  400  that can be clamped to a bottom segment  402  by a pair of clamping bolts  404 . Both segments  400 ,  402  of the clamping bracket include tongues  406  which join in a circle when the segments  400 ,  402  are bolted together, the tongues  406  having a radius and dimensions that fit closely within the support groove segments  304  of the adaptor module  401 . The lower portion  402  of the clamping bracket includes an extension  410  in which a plurality of clearance holes  412  are included. In various embodiments, the sizes and the locations of the clearance holes or tapped holes included in extensions of clamping brackets comply with optical bench hole placement standards, such as the United States standard of ¼ inch×20 tapped or clearance holes spaced one inch apart, or the European standard of 6M tapped or clearance holes spaced 2.5 cm apart. 
         [0037]    The adaptor module  401  of  FIG. 4  can be used to adapt any conflat high vacuum assembly for support by clamping brackets  400 ,  402  of the present invention simply by attaching it to a convenient conflat port of the assembly. If desired, the adaptor module  401  can be inserted between two other UHV modules in the assembly. 
         [0038]      FIG. 5  is a perspective view of a UHV module  500  having two large conflat ports on its top and bottom, and eight smaller conflat ports arranged about its circular perimeter. Two UHV adaptor modules  401 A,  401 B of the type shown in  FIG. 4  have been attached to two opposing smaller conflat ports, and clamping brackets  400 ,  402  have been attached to the supporting grooves of the UHV adaptor modules  401 A,  401 B. The clamping brackets  400 ,  402  are attached to an optical table  500  using standard optical bench accessory brackets  501 , thereby providing mounting of the UHV module  500  to the optical table  502  with optical quality and rigidity. The orientation of the UHV module  500  about an axis passing through the centers of the two UHV adaptor modules can be arbitrarily adjusted simply by loosening the bolts  404  of the clamping brackets  400 ,  402  and rotating the UHV module  500 . The figure also illustrates two other clamping bracket embodiments  504 ,  506 ,  508 ,  510 , shown in two larger sizes. 
         [0039]      FIG. 6A  is a perspective view of a UHV system  600  that comprises a plurality of UHV modules joined by conflat ports. The system  600  includes UHV modules of various shapes and sizes, but is nevertheless substantially linear in design, and requires support by at least two clamping brackets  602 ,  604 , which are attached to the UHV system  600  by support grooves located adjacent to conflat flanges of two of the conflat ports, the clamping brackets  602 ,  604  being attached to an optical bench  502  by means of standard optical bench accessory brackets  501 . If additional support is needed, additional clamping brackets can easily be attached to grooves that are provided adjacent to some of the other conflat ports. The clamping brackets  602 ,  604  are collinear, so that loosening of the conflat brackets  602 ,  604  allows the entire UHV system  600  to be rotated by an arbitrary angle about the common axis of the clamping brackets  602 ,  604 . 
         [0040]    In embodiments of the present invention, support grooves and clamping brackets are used not only for supporting a UHV system, but also for attaching other apparatus to the UHV system in a fixed relationship with the UHV system. The UHV system of  FIG. 6A  includes an additional clamping bracket  606  that is not needed for support of the UHV system  600  on the optical bench  502 . Instead, this additional clamping bracket  606  is used to attach a LASER system  610  directly to the UHV system  600  by means of a standard optical bench accessory bracket  608 , where the LASER  610  in  FIG. 6A  is positioned to direct a LASER beam into the UHV system  600  through an optical window  612  covering a conflat port located directly blow the LASER  610 .  FIG. 6B  is an end view of the UHV system  600  of  FIG. 6A , and  FIG. 6C  is a side view of the UHV system  600  of  FIG. 6A . 
         [0041]      FIG. 7A  is a perspective close up view of a UHV module  700  similar to one of the UHV modules of  FIG. 6A , but including a groove  702  formed in a short extension of the UHV module  700  surrounding one of the conflat ports  703 .  FIG. 7B  shows a clamping bracket  704  attached to the support groove  702  of  FIG. 7A . The clamping bracket  704  includes an extension  706  in which a plurality of tapped holes  708  are provided that comply in both size and placement with an optical bench standard. A standard optical bench accessory bracket  710  can be attached to the extension  706  of the clamping bracket  704  by screws  712 . 
         [0042]    It should be clear to those skilled in the art that many different embodiments of clamping brackets are included in the present invention.  FIGS. 8A and 8B  present detailed front and side view scale drawings respectively of a mounting bracket embodiment similar to the mounting bracket  400 ,  402  of  FIG. 4 .  FIGS. 8C and 8D ,  8 E and  8 F, and  8 G and  8 H present detailed front and side view scale drawings respectively of three other embodiments of clamping brackets that are included in embodiments of the present invention. 
         [0043]    In another general aspect of the present invention, the mounting feature is a plurality of tapped mounting holes that are provided in the body of the UHV module, so that a mounting bracket can be bolted to the UHV module without using or obstructing any of the conflat ports. In embodiments, the mounting holes do not require enlargement of any dimensions of the UHV module.  FIG. 9  is a perspective view of the UHV module  500  of  FIG. 5 . Note that the UHV module  500  includes eight tapped mounting holes  900 , which are located in a circle on the top face of the UHV module  500  at a radius that is outside of the upper conflat port. The tapped mounting holes  900  are symmetrically located between adjacent pairs of the smaller conflat side ports. These locations are well removed from the bolt holes of the smaller conflat ports, so that no increase in any of the dimensions of the UHV module  500  is required. 
         [0044]    A mounting bracket  902  has been bolted to four of the mounting holes  900  by mounting bolts  904 . If needed, a second mounting bracket could be bolted to the other four mounting holes  900 , so as to provide uniform support about the entire upper conflat port. Or a single mounting bracket could be provided that could be bolted to all eight of the mounting holes  900 . Although not visible in the figure, it should be clear that symmetrically identical mounting holes  900  are provided in the bottom face of the UHV module  500  in  FIG. 9 . 
         [0045]      FIG. 10  is a perspective view of a UHV module  1000  that is formed in the shape of a pair of merged adjacent spheres. The UHV module  1000  includes two mounting holes  1002  located symmetrically between a pair of adjacent conflat ports on each side of the UHV module  1000 . Although not visible in the figure, it should be apparent that an identical pair of mounting holes  1002  is provided on the opposite side of the UHV module  1000 . Due to their locations, the mounting holes do not require enlargement of any dimensions of the UHV module  1000 . 
         [0046]    The foregoing description of the embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of this disclosure. It is intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto.