Table 8 Étendue calculation for detectable spot sizes at 30° incidence, 30° collection, with a 50 mm, high NA collection lens.
No servo control (± 50 mm) | With servo control (± 10 mm) | |||
|---|---|---|---|---|
Detectable spot at target surface | Image on detector | Detectable spot at target surface | Image on detector | |
Lateral size of detectable spot, b | ± 50 mm | ± 10 mm | ||
Distance from lens | 280 mm | Equal to focal length | 280 mm | Equal to focal length |
Angular aperture, θcol (half angle) | 5.1° | 27° | 5.1° | 27° |
Étendue = b sinθ | 4.4 mm | ≥ 4.4 mm | 0.89 mm | ≥ 4.4 mm |
Required detector size = \(\frac{{\acute{e} }\text{tendue}}{{\text{sin}}\theta }\) | ± 9.8 mm | ± 2.0 mm | ||
