A technique to produce mirrors for the Auger Observatory

• Published in: IEEE transactions on nuclear science Vol. 48; no. 3; pp. 395 - 399
• Main Authors: Borreani, G., Cartiglia, N., Cester, R., de Capoa, A., de Oliveira, M.A.L., Marchetto, F., Maurizio, D., Pastrone, N.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-06-2001; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Augers; Detectors; Energy measurement; Fluorescence; Glass; Mirrors; Observatories; Oxides; Production; Prototypes; Reflectivity; Segments; Steel
• ISSN: 0018-9499; 1558-1578
• DOI: 10.1109/23.940087

The Fluorescence Detector of the Pierre Auger Cosmic Ray Observatory will provide a measurement of the parameters of extensive air showers with energy >10/sup 19/ eV. The mirror of the Fluorescence Detector prototype has dimension /spl sim/3.6/spl times/3.6 m/sup 2/, and is composed of 49 trapezoidal segments of approximately 50/spl times/50 cm/sup 2/. Each segment is curved using a steel mold in which the glass sags in a controlled environment. The glass is then aluminized under vacuum and coated with oxide (Al/sub 2/O/sub 3/). The oxide thickness is chosen to maximize the reflectivity in the wavelength range of fluorescence light (300 nm</spl lambda/<400 nm). The 49 mirror segments, plus eight spare ones, are now ready for installation. The authors discuss the production technique of the segments for the Torino prototype mirror.