KF40 Vacuum Viewport — KF40 Sight Glass for High Vacuum
KF40 vacuum sight glass (ISO-KF40) for high-vacuum systems. Available in borosilicate, fused silica and sapphire. Compact, quick-install KF flange, optional AR coatings and custom sizes.
Description
KF40 Vacuum Sight Glass (KF40 Viewport) — Compact High-Vacuum Optical Port
KF40 vacuum viewport engineered for high-vacuum process observation, alignment and optical access. Available in borosilicate, fused silica (quartz), and sapphire — selectable by transmission wavelength, thermal resistance and process conditions.
Key benefits
- KF40 flange compatible with standard KF clamps, centering rings, and O-rings for fast install/removal.
- High-vacuum sealing — Viton O-rings or metal gaskets for low leak rates and repeatable seals.
- Material options – borosilicate, fused silica (UV), sapphire (high T/mech), and IR crystals (e.g., CaF₂, ZnSe).
- Compact & modular — ideal for small chambers and quick optical access.
Quick specs (at a glance)
Visible diameter: 40 mm · Outer diameter: 60 mm · Glass thickness: 5 mm · Typical materials: borosilicate/quartz/sapphire.
Technical specifications
| Product model | KF40 |
|---|---|
| Vacuum rating | Leak rate typical: 1×10⁻¹² Pa·m³/s (depending on sealing option) |
| Flange material | Stainless steel 304 (other grades on request) |
| Window materials | Borosilicate · Fused silica (quartz) · Sapphire · BaF₂ · CaF₂ · ZnSe (select by wavelength & temperature) |
| Surface quality / flatness | Surface quality 60/40, 50/20, 20/10 · Optical figure 1/2 to 1/10 (depending on order) |
| Visible aperture (mm) | Ø 40 mm (standard; custom apertures available) |
| Outer / inner diameter | Outer Ø 60 mm · Inner Ø 40 mm |
| Glass thickness & product height | Glass thickness 5 mm · Product height 41.1 mm (standard) |
| Heat resistance (typ.) | ~150–230 °C (depends on material; sapphire/quartz withstand higher bakeout temperatures) |
Typical applications
- Semiconductor processing equipment — plasma observation & process monitoring.
- Vacuum coating and thin-film deposition systems.
- Laboratory and R&D vacuum chambers.
- Laser alignment, spectroscopy and optical diagnostics in vacuum.
- Analytical instruments requiring optical access to high-vacuum environments.
FAQ — KF40 vacuum viewport
What materials are best for UV applications?
Fused silica (quartz) is the preferred choice for deep-UV (down to ~180 nm). Borosilicate blocks below ~300 nm; sapphire is excellent for high temp and mechanical robustness but limits deep-UV transmission.
Can I get custom apertures and higher flatness?
Yes — we provide custom diameters, thicknesses, and optical grades (e.g., 20/10 surface quality, 1/10 wave flatness) on request. CAD drawings available for review.
