Protective windows shaped as spherical domes are used to solve some specific problems. Usually, the domes are used in devices operating under high pressure, with high velocities of incoming air or liquid flows. According to their configuration, the hoods can be smaller than hemispheric, hemispheric and hyperhemispheric.
Depending on the spectral range of the device they protect, the domes can be made of various materials:
The choice of material also depends on the operating conditions.
For harsh operating conditions of the devices, the protective domes used in them are made of sapphire.
|Parameters||Achievable values *|
|Surface finish||Class II|
|Surface irregularity N / ∆N, rings||3/0.5|
|Thickness irregularity, mm||0.02|
|Diameter tolerance, mm||0.05|
|Thickness tolerance, mm||0.05|
* Determined by material and set of parameters.