Vacuum System Developments at the National Synchrotron Radiation Research Center -from the 1.5 GeV TLS to the 3.3 GeV TPS

Abstract

This article describes the design and operation of the vacuum system of the 1.5 GeV Taiwan Light Source (TLS) at the National Synchrotron Radiation Research Center (NSRRC). The TLS vacuum system has aluminum beam ducts, an oil-less fabrication process, a low impedance structure, an oil-less pumping system, little dust and an effective vacuum safety interlock system. Operating already for 12 years, TLS vacuum system has been highly reliable. A low-emittance 3.3 GeV synchrotron light source, the Taiwan Photon Source (TPS, with a circumference of 518.4 m), at the NSRRC is proposed to meet the requirements of advanced scientific study. Given the strictness of these requirements, the TPS vacuum system must be constructed to perform well in many areas, with a low vacuum pressure, little dust, a stable mechanical structure and a low risk of material failure caused by a high heat load or radiation damage. The vacuum system of the TPS has been preliminarily designed based on experience gained at the TLS. This work presents the technical design of the TPS vacuum chambers, the pumping configuration and some special components, emphasizing the considerations in obtaining an ultrahigh vacuum, the factors that influence beam quality and the reliability of the vacuum system.