Frequency Scanned Interferometry for ILC Tracker Alignment

TL;DR

This paper demonstrates high-precision distance and vibration measurements using frequency scanned interferometry with dual-laser techniques, achieving 0.3-micron accuracy over half a meter, relevant for tracker alignment.

Contribution

Introduces a dual-laser scanning method and a multi-channel FSI system for improved absolute distance measurement accuracy.

Findings

Achieved 0.3 micron precision over 0.57 meters

Developed a dual-channel FSI system for practical applications

Demonstrated potential for silicon tracker optical alignment

Abstract

In this paper, we report high-precision absolute distance and vibration measurements performed with frequency scanned interferometry. Absolute distance was determined by counting the interference fringes produced while scanning the laser frequency. High-finesse Fabry-Perot interferometers were used to determine frequency changes during scanning. A dual-laser scanning technique was used to cancel drift errors to improve the absolute distance measurement precision. A new dual-channel FSI demonstration system is also presented which is an interim stage toward practical application of multi-channel distance measurement. Under realistic conditions, a precision of 0.3 microns was achieved for an absolute distance of 0.57 meters. A possible optical alignment system for a silicon tracker is also presented.