Monitoring of absolute mirror alignment at COMPASS RICH-1 detector

0435037 - ÚFP 2015 RIV NL eng J - Journal Article
Alexeev, M. - Birsa, R. - Bradamante, F. - Bressan, A. - Chiosso, M. - Ciliberti, P. - Dalla Torre, S. - Denisov, O. - Duic, V. - Ferrero, A. - Finger, M. - Finger jr., M. - Gayde, J.Ch. - Giorgi, M. - Gobbo, B. - Levorato, S. - Maggiora, A. - Martin, A. - Menon, G. - Panzieri, D. - Pesaro, G. - Polák, Jaroslav - Rocco, E. - Sbrizzai, G. - Schiavon, P. - Slunečka, M. - Sozzi, F. - Steiger, Lukáš - Šulc, Miroslav - Takekawa, S. - Tessarotto, F.
Monitoring of absolute mirror alignment at COMPASS RICH-1 detector.
Nuclear Instruments & Methods in Physics Research Section A. Roč. 766, December (2014), s. 208-211. ISSN 0168-9002. E-ISSN 1872-9576.
[International Workshop on Ring Imaging Cherenkov Detectors (RICH 2013)/8./. Hayama, Kanagawa, 02.12.2013-06.12.2013]
Institutional support: RVO:61389021
Keywords : RICH * Cherenkov radiation * Mirror alignment * Photogrammetry
Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders
Impact factor: 1.216, year: 2014
http://www.sciencedirect.com/science/article/pii/S0168900214008134#

The gaseous COMPASS RICH-1 detector uses two spherical mirror surfaces, segmented into 116 individual mirrors, to focus the Cherenkov photons onto the detector plane. Any mirror misalignment directly affects the detector resolution. The on-line Continuous Line Alignment and Monitoring (CLAM) photogrammetry-based method has been implemented to measure the alignment of individual mirrors which can be characterized by the center of curvature. The mirror wall reflects a regular grid of retroreflective strips placed inside the detector vessel. Then, the position of each mirror is determined from the image of the grid reflection. The images are collected by four cameras. Any small mirror misalignment results in changes of the grid lines’ positions in the image. The accuracy limits of the CLAM method were checked by laser interferometry and are below 0.1 mrad
Permanent Link: http://hdl.handle.net/11104/0238955