Calcium Fluoride Zero Length Viewports

VacTechniche Vacuum Optics – Viewports

Calcium Fluoride Zero Length Viewports

VacTechniche calcium fluoride viewports are offered in CF, ISO and KF flange styles. The clean, UHV CF versions are offered using 304L or 316LN stainless steel flanges. Non-magnetic viewports are offered as standard using annealed stainless steel weld rings and high grade 316LN and CF flanges. Flanges in 316L stainless steel are used for the high vacuum KF and ISO viewports.



The rugged, bonded construction of the calcium fluoride viewports allows bake-out to a maximum of 120 °C with ultra high vacuum (UHV) performance whilst the window offers extended broadband optical transmission from deep UV to the infrared. Specially coated optics optimised to minimise reflecance at customer specified wavelength can be quoted on request.

Non-standard viewports can be manufactured on request, including re-entrant style microscope/camera viewports. Annealed copper gaskets and other component accessories are also supplied by VacTechniche.

Transmission Curve – Calcium Fluoride


Seal Type Bond
Maximum Temperature 120°C
Minimum Temperature minus 20°C
Maximum Rate of Temperature Change 3°C per minute
Leak Rate <1×10-10 atm-cc/sec (He)
Pressure range 1 bar to 1×10-9 mbar
Surface quality 60 /40 scratch/dig
Flatness (prior to bonding) λ/4

Cross Sections / Diagrams

Parts & Variations

Part Number Flange Type OD mm View Diameter mm Optic Thickness mm Flange Thickness mm Flange Material Weld Ring Material Non-Magnetic
BVPZ16CaF2 NW16CF 34 15 1.5 12.7 304L 316L
BVPZ16CaF2-NM NW16CF 34 15 1.5 12.7 316LN 316L Annealed Yes
BVPZ38CaF2 NW35CF 70 32 3 12.7 304L 316L
BVPZ38LACaF2 NW35CF 70 38 3.5 12.7 304L 316L
BVPZ38CaF2-NM NW35CF 70 32 3 12.7 316LN 316L Annealed Yes
BVPZ64CaF2 NW63CF 114 63 5 17.4 304L 316L
BVPZ64CaF2-NM NW63CF 114 63 5 17.4 316LN 316L Annealed Yes