The Position and Correction System of Laser PSD

Abstract

A laser PSD positioning system is included in the TPS girder auto-alignment system that is designed for aligning and positioning the straight-segment girders of TPS storage ring. The laser PSD positioning system consists of lasers, PSD, and lenses. This chapter describes the process of assembly, installation, adjustment, and the measurement result of the laser PSD system. Installing the laser PSD system consists of several steps. The first step is to assemble lenses and PSD in mechanism, lens PSD module. The tilt angles of lens on the lens PSD module are fine tuned and the PSD position value is adjusted to zero. The positioning fixture is designed and contains six touch sensors (absolute length gauges) for detecting the position of the lens PSD module. The lens PSD module is installed and adjusted on a girder absolute position precisely by the positioning fixture. So each module is adjusted to with equal distance to the vertical and horizontal reference plane of girder. The laser is adjusted according to the position of the PSD. Finally, use the absolute length gauges to correct the PSD. According to the aforementioned process of assembly and all parameters of PSD module, the girder can be aligned and positioned within 20 um precision scale.