SN0392 : MATRIX ANALYSIS OF AN FTPC LASER DISTRIBUTION MIRROR SYSTEM

Author(s):J. Draper
Date:Apr. 12, 1999
File(s):sn0392.pdf
Abstract:Properties are derived for matrices needed to describe the trajectory of a laser beam through an arbitrary three-dimensional system of mirrors with arbitrary angles of orientation. From these ingredients, a computer program using Euler rotation matrices has been written which can be applied to the analysis of any mirror-only laser distribution system. The STAR TPC laser calibration system is an example of such a system. Using this program, an analysis is made of a hypothetical but reasonably realistic laser calibration system for the STAR FTPCs. The angular orientation of each mirror can be adjusted by a small rotation about either of two arbitrary but orthogonal axes in the plane of the mirror. The errors in beam positioning at each successive mirror are evaluated quantitatively, as produced by arbitrary adjustments of any subset of the mirrors. The ability to steer the beam reproducibly by remote control of the adjustments of two of the mirrors is considered. The stabilizing effect of having a tiny (1-mm) mirror just before the beam(s) through the FTPC gas is analyzed. The effects of the mechanical shifting of the STAR magnet pole piece are shown to be unimportant.
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Category:Technical