Ultra-High-Vacuum Fiber Feedthrough Flanges

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Ultra-High Vacuum Fiber Feedthrough CF Flange Cross-Section

• Construction Enables use at Vacuum Pressures Down to
  1 x 10^-10 Torr
• Mates to Ø2.75" (DN40) CF Flanges
• Hermetically-Sealed Fiber Tip Limits Virtual Leaks
• 304 Stainless Steel Construction for High Durability and Low Outgassing
• Laser Welded Body; Adhesive-Free on Vacuum Side
• CF Flange Mounting Hardware Pack and Copper Gaskets Sold Below

Our Ultra-High-Vacuum-Compatible Ø2.75" (DN40) Fiber Feedthrough CF Flanges allow for optical coupling into ultra-high-vacuum (UHV) systems using SMA905-terminated fiber patch cables and mating sleeves. Constructed using 304 stainless steel, every feedthrough is designed to be used within UHV systems down to 10^-10 Torr.

The CF-style flange utilizes a knife-edge mechanism to create an airtight seal when used properly with a copper gasket (sold below). Six 1/4" (M6) through holes allow the these fiber feedthroughs to be bolted onto any standard DN40 CF flange. As the bolts of the mating pair are tightened, the knife edge bites into the copper gasket, deforming it. The compressed copper fills all the machining marks and surface defects, which yields a leak-tight seal. Please note that the copper gasket and bolts must be purchased separately.

Note: Mounting hardware and CF flange copper gasket seals are not included.

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This cross-section illustrates the interior of our UHV high- and low-OH fiber feedthrough KF40 flanges.

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• Construction Enables use at Vacuum Pressures Down to 1 x 10^-8 Torr
• Mates to KF40 (Ø2.17") Flanges
• Hermetically-Sealed Fiber Tip Limits Virtual Leaks
• 304 Stainless Steel Construction for High Durability and Low Outgassing
• Laser Welded Body on High- and Low-OH Fiber Feedthroughs
• High-OH and Low-OH Fiber Feedthroughs Adhesive-Free on Vacuum Side
• KF40 Flange-Centering O-Ring Carrier and Wing Nut Clamp Sold Below

Our Ultra-High-Vacuum-Compatible Fiber Feedthrough KF40 Flanges allow for optical coupling into ultra-high-vacuum (UHV) systems using SMA905-terminated fiber patch cables and mating sleeves. Constructed using 304 stainless steel, every feedthrough is designed to be used within UHV systems down to 10^-8 Torr. Referred to as NW, QF, or DN flanges, KF flanges are ideal for quickly assembling vacuum systems due to their ease of use, maintenance, and reusability. The MIR fiber feedthrough (Item # VK4F1S) has a 17.78" (451.6 mm) long, ruggedized, hermetic, permanently attached, InF₃ multimode fiber cable ending in a male SMA905 connector on the side facing away from vacuum.

These KF flanges are ISO-standardized vacuum fittings that can be mated to a vacuum system using a wing nut clamp and an O-ring carrier (sold below). The angled sides of the wing nut clamp compress the O-ring between the flanges, quickly creating a vacuum seal. The wing nut clamp, which has M5 x 0.8 threads, requires only hand tightening, allowing parts to be quickly swapped in and out of a KF-flanged system. Please note that the O-ring carrier and wing nut clamp must be purchased separately.

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The ADASMAV has a Ø0.063" (Ø1.6 mm) vent hole.

• Air-Spaced SMA to SMA Mating Sleeve for Ultra-High-Vacuum Applications
• Constructed from 304 Stainless Steel
• <1.5 dB Insertion Loss (Typical Loss for a Pair of Ø200 µm Core Multimode Fibers)
• Double-Bagged for Cleanroom Environments
• Compatible with Thorlabs' Vacuum-Compatible Multimode Fiber Optic Patch Cables

Thorlabs' ADASMAV Mating Sleeve is a vacuum-compatible version of the ADASMA SMA to SMA Mating Sleeve. Constructed using 304 stainless steel, this adapter is designed to be used within ultra-high vacuum systems (>10^-10 Torr) and features a Ø0.063" (Ø1.6 mm) vent hole in the side to allow trapped gases to escape (see image to the right). Unlike the standard version, the ADASMAV is only compatible with SMA905-style connectors. A 304 stainless steel washer and nut are included for custom mounting.

Vacuum Compatibility Information
Our vacuum-compatible adapter is chemically cleaned and prepared for vacuum applications before packaging. It is compatible directly out of the packaging with vacuum environments down to 10^-10 Torr. With additional cleaning and processing, it can be used at even lower pressures, only limited by the outgassing rate of the stainless steel (see the table above). The material properties of the stainless steel and the cleaning methods completed by the end user should be used to determine the appropriateness of these products and materials in a specific vacuum system. Please note that using caps or panels not rated for vacuum applications with the ADASMAV is not recommended.

We also offer other vacuum-compatible components which may be used in vacuum applications.

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VGA10 Copper Gasket Installed on VPCHW42-C Viewport

• VMH6 Stainless Steel (18-8) Mounting Hardware Set Includes:
  • Six Bolts (Silver-Plated, 1/4"-28 x 1.50", 12-Point Heads)
  • Six Nuts and Twelve Washers
• Single-Use Copper Gaskets for Forming a Seal Between Ø2.75" CF Flanges
  
  • 101 Copper Alloy (99.99% Pure), OFHC (Oxygen-Free High Conductivity)
  • VGC10: 1/4-Hard Copper Gaskets
  • VGA10: Annealed Copper Gaskets

Thorlabs offers mounting hardware and single-use copper gaskets for mating Ø2.75" CF flanges. These flanges utilize a knife-edge mechanism to create an airtight seal between mating pieces. To create the seal, a copper gasket is most often employed. As the bolts of the mating pair are tightened, the knife edge bites into the copper gasket, deforming it. The extruded metal fills all the machining marks and surface defects, which yields a leak-tight seal.

1/4-hard and annealed copper gaskets are sold in sets of 10. We recommend the 1/4-hard copper gaskets for most applications; for more delicate devices, such as viewports, we recommend using the softer annealed copper gaskets to lower the chance of deformation in the optic due to stress in the flange. The set of stainless steel mounting hardware includes six silver-plated bolts, six nuts, and twelve washers. The silver plating on the bolts acts as a lubricant to prevent galling between the stainless steel surfaces of the bolt and the nut.

Instructions
First ensure the knife-edge mating surfaces of the CF flanges are free from debris or scratches. Then choose the desired bolt hole orientation and insert the gasket, aligning leak-test grooves on the flanges if present. Slide a washer onto the bolt, insert the bolt through the flanges, and add another washer before screwing on the nut. Hand tighten each bolt, then use two wrenches to hold the bolt head and turn the nut. Tighten the nuts gradually in 1/8 to 1/4 turn increments in an alternating crisscross star pattern until the desired tightness is reached. Following these steps will result in a reliable seal with even gasket compression and deformation.

• KF40CR-F Centering O-Ring Carrier for KF40 (Ø2.17") Flanges
  • Holds O-Ring in Place Between KF Flanges
  • Creates Vacuum Seal When Compressed Against KF Mating Surfaces
  • Includes Fluorocarbon O-Ring
• KF40WNC Wing Nut Clamp for KF40 (Ø2.17") Flanges
  • Secures Two KF40 Flanges Separated by an O-Ring
  • Fast Hand Tightening; No Tools Required

Thorlabs offers a centering O-ring and a wing nut fastening clamp for mating KF40 flanges to a vacuum system. The angled sides of the wing nut clamp compress the O-ring between the flanges, quickly creating a vacuum seal. The wing nut clamp, which has M5 x 0.8 threads, requires only hand tightening, allowing parts to be quickly swapped in and out of a KF-flanged system.

For best performance, a very thin coating of vacuum grease should be applied to the O-ring before installation. This should be done by hand while wearing gloves, leaving just enough grease to cause the O-ring to shine. The O-ring and its mating surfaces should be visually inspected before installation to ensure there is no debris which may impede proper contact and cause a leak. O-rings should be regularly inspected to spot dry rot, cracking, tearing, or accumulation of debris from normal operation. Replace any O-ring that is suspected of causing a leak. Additionally, be aware that under vacuum pressure, the KF connection may undergo additional compression, causing the wing nut clamp to loosen. Some additional tightening may be performed, but be careful not to overtighten the clamp, as the wing nut may become difficult to remove or jammed when the system returns to atmospheric pressure. Do not remove a wing nut clamp while a system is under vacuum.

We also offer KF16 and KF25 flange sizes of wing nut clamps and O-rings.