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Courtesy of U. Hawaii group:. Super-Belle. Belle. Other Focussing R&D M. Belhorn, A. Drutskoy, P. Goldenzweig, A. J. Schwartz University of Cincinnati, USA. Babar’s DIRC detector is a proven success - but not easily adapted to Super-Belle.
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Courtesy of U. Hawaii group: Super-Belle Belle Other Focussing R&DM. Belhorn, A. Drutskoy, P. Goldenzweig, A. J. SchwartzUniversity of Cincinnati, USA Babar’s DIRC detector is a proven success - but not easily adapted to Super-Belle. Absence of gap in magnet yoke to bring quartz+light out prescribes that imaging be done inside magnet AND that image must be small.
STRATEGY: Use focusing to reduce image; this has the advantage of ~eliminating smearing due to bar thickness (as parallel photons are imaged to a point). To reduce space needed, use quartz radiator itself as the “stand-off” medium, i.e., focus at one end of bar, image at the other:
ISSUES: • Small image needs fine phototube segmentation e.g., Burle/Photonis MCP, Hamamatsu multi-anode • photons displaced from optical axis of spherical focusing mirror • ⇒ spherical aberration, focal point not sharp • photons not paraxial with respect to mirror • ⇒ astigmatism, focal points in x and y separate • long bar length relative to bar width causes photon hit pattern to “fold back” on itself • ⇒ “smile/frown” hit pattern has ambiguities } CT < CX + XT CT < 2CX 2CF < 2CX CF < CX }
Epoxy-ing mirror to bar Tried NOA61, 63, 84; we then chose 63 (easiest to work with) Mirror optic UV lamp Bar
