Ultra-High-Vacuum Fiber Feedthrough CF Flanges

• Ø2.75" (DN40), Male SMA905 Terminated Fiber Feedthrough CF Flanges
• Multimode Step Index Optical Fiber with Ø200 µm Core
• Double-Bagged for Cleanroom Environments

Thorlabs' Ø2.75" (DN40) Fiber Feedthrough CF Flanges are fixed (non-rotating) flanges with male SMA905 fiber connectors on both sides. The fibers are held in place by a glass-ceramic hermetic seal, creating an airtight feedthrough that is suitable for use with chambers operating at pressures down to 10^-10 Torr. Mating sleeves may be used to connect fiber patch cables to the feedthrough; we recommend the ADASMAV (sold below) when mating a patch cable to the CF flange on the vacuum side. These flanges have six 1/4" (M6) through holes for bolting onto any standard DN40 CF flange.

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

Item #	Wavelength Range	Fiber Core Diameter	Attenuation Range (Click to Enlarge)	NA	Vacuum Level	Insertion Loss	Max Optical Power	Max Temperature
VC2H2S	200 - 1200 nm	200 µm		0.22 ± 0.02	1 × 10-10 Torr	≤2.3 dB	1 W	250 °C
VC2L2S	400 - 2400 nm

• Ø2.75" (DN40), Male SMA905 Terminated Fiber Feedthrough CF Flanges
• Multimode Step Index Optical Fiber with Ø600 µm Core
• Double-Bagged for Cleanroom Environments

Thorlabs' Ø2.75" (DN40) Fiber Feedthrough CF Flanges are fixed (non-rotating) flanges with male SMA905 fiber connectors on both sides. The fibers are held in place by a glass-ceramic hermetic seal, creating an airtight feedthrough that is suitable for use with chambers operating at pressures down to 10^-10 Torr. Mating sleeves may be used to connect fiber patch cables to the feedthrough; we recommend the ADASMAV (sold below) when mating a patch cable to the CF flange on the vacuum side. These flanges have six 1/4" (M6) through holes for bolting onto any standard DN40 CF flange.

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

Item #	Wavelength Range	Fiber Core Diameter	Attenuation Range (Click to Enlarge)	NA	Vacuum Level	Insertion Loss	Max Optical Power	Max Temperature
V2H6S	200 - 800 nm	600 µm		0.22 ± 0.02	1 × 10-10 Torr	≤2.3 dB	1 W	250 °C
V2L6S	400 - 2200 nm

Click to Enlarge
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 using the softer annealed copper gaskets with viewports 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.