Geometry and optics calibration for air fluorescence detectors using star light High Resolution Fly’s Eye Collaboration
نویسندگان
چکیده
The high resolution Fly’s Eye (HiRes) detector in Dugway, Utah, is an air fluorescence detector designed for the measurement of the energy and arrival direction of cosmic ray particles with energy E > 10 eV. HiRes monitors the night sky for fluorescence light from air shower cascades induced by cosmic ray primaries. The light is collected by mirrors and projected onto arrays of photomultiplier tubes that provide an image of the air shower. Corresponding author. Tel.: +1-212-854-3316; fax: +1-212-854-3366. E-mail address: [email protected] (S. Westerhoff). 0927-6505/02/$ see front matter 2002 Elsevier Science B.V. All rights reserved. PII: S0927-6505 (02 )00143-3 Astroparticle Physics 18 (2002) 237–248 www.elsevier.com/locate/astropart HiRes is an astronomical instrument, and the accuracy of the mirror pointing and understanding of the optical properties of the mirror–camera units is crucial. We present a method to cross-check and monitor the mirror pointing by using star light. A star crossing the field of view of a photomultiplier tube causes a temporary increase in the total light detected by the tube. Using UV bright stars, we analyze the pointing accuracy of the HiRes 2 detector, and evaluate the shape of a point-like object as a function of distance to the mirror axis. 2002 Elsevier Science B.V. All rights reserved. PACS: 95.55.Vj; 95.45.þi; 95.85.Ry
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