VC224
Ø1" Flat Window Viewport,
Uncoated CaF2 (180 nm - 8 µm)
Front
VGA10
Annealed Copper Gaskets,
10 Pack
Back
VMH6
Flange Mounting Hardware Pack
(6 Bolts, 6 Nuts, & 12 Washers)
VC22VO
Viton O-Ring
Common Vacuum Specifications | |
---|---|
Vacuum Level | 1 x 10-8 Torr (Max) |
Max Temperature | 150 °C |
Thermal Gradient | 20 °C/min (Max) |
Thorlabs' high-vacuum-compatible Ø2.75" (DN40) CF Flange Viewports for Ø1" Optics are offered with one of three uncoated window substrates: sapphire (200 nm - 4.5 µm), CaF2 (180 nm - 8.0 µm), or UVFS (185 nm - 2.1 µm). Please see the Graphs tab for transmission data. Additionally these viewports are compatible with our selection of stock Ø1" flat windows with thicknesses between 4.9 - 5.15 mm. These flanges are not compatible with wedged windows.
Designed for use at high-vacuum (HV) pressures, Thorlabs' CF viewports utilize Viton O-Ring seals to create an air-tight metal/glass seal, allowing for pressures down to 10-8 Torr. The vacuum windows are interchangeable, enabling the user to swap out vacuum windows mounted in our HV CF flanges. Additionally, CF flanges (viewports without vacuum windows) are also available that are also compatible with our Ø1" windows. Before swapping and attempting to install additional windows, please review the procedure outlined in the Window Installation tab above.
Copper gasket and mounting hardware sets for Ø2.75" CF flanges are also available below. Thorlabs also offers HV CF Flange Viewports for Ø1.5" flat windows and Ø1.5" wedged windows.
Flange Item # | VC223 | VC225 | VC224 |
---|---|---|---|
Window Materiala | Sapphire | Calcium Fluoride | UV Fused Silica |
Window Diameter (Unmounted) | 1" (25.4 mm) | ||
Window Thickness (Unmounted) | 0.20" (5.0 mm) | ||
Clear Apertureb | Ø0.71" (Ø18 mm) | ||
Transmitted Wavefront Error @ 633 nmc | λ | λ/8 | λ/10 |
Surface Quality | 60-40 Scratch-Dig | 20-10 Scratch-Dig | |
Parallelism | <3 arcmin | <10 arcsec | <5 arcsec |
Replacement Window Item #d | WG31050 | WG51050 | WG41050 |
The graphs below show the transmission of light through uncoated sapphire, calcium fluoride (CaF2), and UV fused silica substrates. Raw data in the Excel format is available by clicking on the links below the graphs.
Our high-vacuum viewports allow the user to install or swap out windows as they desire, or as experimental conditions demand. Installation of the windows is relatively quick and simple. The following steps describe how to install and change windows in our high-vacuum CF flanges.
Step 1: Inspect the O-ring and seat for pits, scratches, or contamination. Remove any loose debris from the seat using compressed air and then install the O-ring in the seat (see Fig. 1). If necessary, clean the window by following our optics cleaning tutorial.
Step 2: Place the window on top of the O-ring (see Fig. 2) and then place and center the second O-ring on top of the window (see Fig. 3).
Step 3: Set the faceplate on top of the window, lining up the O-ring with the faceplate groove and the six holes in the faceplate with the threaded holes in the flange (see Fig. 4). Do not slide the part across the window surface.
Step 4: Place the six screws in the faceplate holes and use a 5/64" (2.0 mm) hex key to thread them so that they are just making contact with the faceplate.
Step 5: In the order illustrated in Fig. 5, turn each screw a quarter turn, repeating the pattern until the faceplate is tight against the flange.
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A vacuum coupling that supports operation at ultra-high-vacuum levels
Damage to the knife edge, an aggressive approach to tightening the bolts, and reusing gaskets can all result in leaky CF vacuum couplings. The techniques demonstrated in this video reduce the risk presented by these factors, which are all related to the limited malleability of the metal gasket. It is important that the knife edges are in pristine condition, since the gasket is not soft enough to fill narrow or abrupt features, such as a nick in a knife edge. An approach of gradually and iteratively tightening the bolts is effective in maintaining a uniform thickness of the gasket around its circumference, while tightening each bolt all at once can result in thickness variations in the gasket that are difficult or impossible to flatten. This is a consequence of the metal gasket’s limited ability to flow and can result in gaps between the gasket and knife edges. Using a new gasket is always recommended. Even a gasket that was only partially compressed during a previous use may not be malleable enough, when reused, to conform to the contours of the knife edges. This is because compression has the effect of strain (work) hardening the metal.
While a leaky vacuum connection can result in time lost to leak checking and re-opening the vacuum system to locate and fix the problem, productive work can also be delayed as a result of broken or malfunctioning components in or attached to the chamber. Due to this, an overview of special considerations for handling and using fiber feedthroughs is also included in this video.
If you would like more information about tips, tricks, and other methods we often use in the lab, we recommend our other Video Insights. In addition, our webinars provide practical and theoretical introductions to our different products.
ConFlat® is a registered trademark of Agilent Technologies, Inc.
Products Featured During Demonstration | |||
Optical Fiber Feedthrough | 1/4-Hard Copper Gaskets | Fiber Inspection Scope | Nitrile Gloves |
UHV Fiber Patch Cable | Solvent Dispenser | Fiber Connector Cleaner | Wipes |
Date of Last Edit: Sept. 21, 2022
Thorlabs' Ø2.75" CF flange viewports allow for optical access into high-vacuum (HV) systems down to 10-8 Torr. These are fixed (non-rotating) flanges with Ø1" windows that provide a Ø0.71" (Ø18 mm) clear aperture (CA). Note that the CA is limited by the optic rather than the flange's internal diameter. These viewports have six 1/4" (M6) through holes for bolting onto any standard Ø2.75" CF flange. Please note that mounting hardware is not included. Our HV CF viewports can be purchased with one of three uncoated windows: sapphire, CaF2, or UVFS. Additionally, the provided window may be replaced with any of our Ø1" flat windows that are 4.9 - 5.15 mm thick.
Part Number | Description | Price | Availability |
---|---|---|---|
VC223 | Ø2.75" CF Flange, 200 nm - 4.5 µm Uncoated Sapphire Window | $244.70 | Today |
VC225 | Ø2.75" CF Flange, 180 nm - 8 µm Uncoated CaF2 Window | $250.65 | Today |
VC224 | Ø2.75" CF Flange, 185 nm - 2.1 µm Uncoated UVFS Window | $244.70 | Lead Time |
Thorlabs' Ø2.75" CF flange does not include a window but is compatible with any Thorlabs Ø1" window that is 4.9 to 5.15 mm thick. When combined with the appropriate window, this flange allows for optical access into high-vacuum (HV) systems down to 10-8 Torr. This fixed (non-rotating) flange has six 1/4" (M6) through holes for bolting onto any standard Ø2.75" CF flange. Please note that mounting hardware is not included.
The CF-style flange utilizes a knife-edge mechanism to create an airtight seal between mating pieces. To create the seal, a copper gasket (available below) 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 any machining marks or surface defects, yielding a leak-tight seal.
Part Number | Description | Price | Availability |
---|---|---|---|
VC22FL | Ø2.75" CF Flange for Ø1" Optics | $125.92 | Today |
VC22VO | Viton O-Ring for Ø1" Vacuum Window, Pack of 5 | $12.08 | Today |
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.
Part Number | Description | Price | Availability |
---|---|---|---|
VMH6 | Mounting Hardware for CF Flanges: 6 Silver-Plated Bolts, 6 Nuts, 12 Washers | $19.23 | Today |
VGC10 | 1/4-Hard OFHC 99.99% Pure Copper Gaskets for Ø2.75" CF Flange, 10 Pack | $45.23 | Today |
VGA10 | Annealed OFHC 99.99% Pure Copper Gaskets for Ø2.75" CF Flange, 10 Pack | $101.77 | Today |