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Atlas CFTA™ All-Metal UHV Sealing for Non-Magnetic Aluminum Vacuum Chambers

The Atlas CFTA™ Aluminum flange body bonded to Titanium uses the time-tested reliability of the ConFlat® (CF) knife-edge seal. After welding the CFTA™ flange to an aluminum vacuum chamber, it becomes a completely non-magnetic UHV chamber.

Non-magnetic aluminum vacuum chambers will not interact with magnetic environments. Non-magnetic vacuums are used for UHV synchrotron, particle physics, and industrial applications where high magnetic permeability is detrimental to beam quality or experimental results. Such applications include non-magnetic beam tubes, wigglers, undulators, free electron lasers (FEL), drift tubes, and spectrometers.


Aluminum vacuum chambers utilized in nuclear applications use CFTA™ flanges that are Low Z. In neutron applications such as the production of radioisotopes for medical imaging, aluminum vessels fitted with our flanges replace all-stainless UHV systems. Residual, neutron-induced radiation in aluminum has a half-life an order of magnitude shorter than that of stainless steel (which contains Cobalt and Chrome). Our CFTA™ flanges enable aluminum UHV systems to be used in high-magnetic environments like cyclotrons and nuclear reactors.

Light/low weight Atlas CFTA™ Flanges: These are excellent for weight-sensitive applications such as aerospace or portable systems. Weight-to-volume ratios are 1/3 that of stainless vacuum chambers; this allows engineers to significantly reduce overall weight. Depending on size, reduced-thickness titanium/aluminum flanges are produced with a titanium layer that’s approximately 20% to 40% thinner than standard Atlas flanges. Contact our sales department for more information on our custom bimetallic HV and UHV solutions.

  • Atlas CFTA™ Flanges are suitable for service in vacuum levels to 1×10 -13+ Torr and 250°C bake-out temperatures. Our bimetallic flanges can be easily welded to aluminum vacuum vessels and are the key to successful integration of aluminum UHV technology in your application.
  • Atlas titanium-to-aluminum bimetallic flanges are fully compatible with the industry standard ConFlat® flange interface. Employing CERN’s innovative 20° back-bevel (90° included angle) (Figure 1) knife-edge design, the Atlas CFTA™ Flange provides a longer service life than conventional CF flanges.
  • Atlas flanges are used in prominent HV, UHV, and XHV applications around the world. They find extensive use with semiconductor fabrication OEMs where superior heat conduction, chemical resistance, manufacturing ease, and the lower cost of aluminum vacuum systems translates into measurable productivity and cost-of-ownership advantages.


  • UHV Rated to 1×10 -13+ Torr
  • 1/3 the weight of stainless flanges.
  • 90° included angle, long-life knife-edge design, developed at CERN.
  • 100% Compatible with the industry standard ConFlat® interface.
  • Standard Flange sizes 1.33 –16.5”


  • Body/Weld Interface: Aluminum 6061-T6
  • Sealing Knife-Edge Face: Titanium Grade 2, Titanium (Commercially Pure) Optional
  • Rotatable Collar/Receiver: Aluminum 6061-T6, Titanium Optional


  • Vacuum Leak Tested: < 1 x 10-9 cc/sec of He


  • Peak Temperature: 300°C (during weld-up)
  • Operational Temperature: -200°C to 250°C

Mechanical—Explosion Bonded Interface

  • Tensile: 15,00psi (103MPa)
  • Shear: 10,000psi (69MPa)

Diagrams & Variations

Choose Size

Click images above for larger version.

Rotation Bore Bolt Holes Part # Hardware Files Actions
Non-Rotatable Blank 0.172 Clearance CFTA-0133-04 Show
Non-Rotatable .50" 0.172 Clearance CFTA-0133-01 Show
Non-Rotatable .50" Tapped 8-32 CFTA-0133-11 Show
Non-Rotatable Blank 8-32 US Tap CFTA-0133-14 Show
Non-Rotatable .50" M4x.07 mm Tap CFTA-0133-21 Show
Non-Rotatable Blank M4x.07 mm Tap CFTA-0133-24 Show
Rotation Bore Bolt Holes Part # Hardware Files Actions
Non-Rotatable .50" 0.172 Clearance CFTA-0133-02 Show
Non-Rotatable Blank 0.172 Clearance CFTA-0133-05 Show
Non-Rotatable .50" 8-32 US Tap CFTA-0133-12 Show
Non-Rotatable Blank 8-32 US Tap CFTA-0133-15 Show
Non-Rotatable .50" M4x.07 mm Tap CFTA-0133-22 Show
Non-Rotatable Blank M4x.07 mm Tap CFTA-0133-25 Show
Rotatable .50" 0.172 Clearance CFTA-0133-03 Show
Rotatable Blank 0.172 Clearance CFTA-0133-06 Show
Rotatable .50" 8-32 US Tap CFTA-0133-13 Show
Rotatable Blank 8-32 US Tap CFTA-0133-16 Show
Rotatable .50" M4x.07 mm Tap CFTA-0133-23 Show
Rotatable Blank M4x.07 mm Tap CFTA-0133-26 Show

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