Abstract
Superconducting magnets have become essential components of large accelerators/colliders. Their technology has greatly progressed because of the production of Tevatron, HERA, and RHIC magnets and the intense R&D programs for SSC and LHC. In KEK superconducting quadrupole magnets, which are the first superconducting accelerator magnets in Japan, were developed in the 1980s and installed into the interaction regions of the TRISTAN collider. Since commissioned in February 1991, the magnets had operated five years without serious trouble and contributed to double the luminosity. This paper describes the features and the construction history of the magnet systems.
