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["Kiselev, Alexander" <ayk AT bnl.gov>]

   Hello colleagues,

  attached is a paragraph, which did not make it into one of my proposals written almost two years ago. Assuming that these lenses really have high enough optical properties (yet to be demonstrated), a ring in such a system would be split into up to three pieces, each sitting in the inner (active) area of a particular LAPPD. Or up to four pieces if square lens fragments and square HRPPD tiles are used.

  The problem which was conveniently omitted in this paragraph is: what happens at large angles? It can be though, that segmenting aerogel in three (or 4-5) radial bands a la Belle II allows one to keep aerogel assembly surface flat, but tilt the Fresnel lens bands separately, making them "more or less projective". Or perhaps even tilt the aerogel bands themselves together with the lenses, as it was suggested by Elke. The substantial focal depth of these lenses may still allow one to keep the sensor surface flat (which seems to be a must). Something to consider.

  Regards,

    Alexander.

Attachment: mrich.pdf
Description: mrich.pdf