What does the diffuser look like?
Drawing with dimensions of diffuser BAT 5
The diffuser’s distance to fibre distance is matched to the fibre’s N.A. There is a slight slope in the diffuser’s surface to drain the water through a drainage hole. An 'o'-ring gives additional protection against rain.
The diffuser can be made in almost any size. Here is a slightly smaller model:
Drawing with dimensions of diffuser BAT 6
Characteristics of the smaller and bigger diffuser are almost the same.
Diffuser characteristics
- Good Cosine response with known correction factors.
- Reasonably good random polarised transmission independent to temperature changes.
- Transmission insesitive to geometrical changes (~0.25 mm)
- Cosine response insensitive to geometrical changes
- Solid weatherproof design
- Negligibly small azimuth errors
- No spikes in signal at higher wavelengths
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