High level of integration of front-end imaging optics system for electron cyclotron emission imaging diagnostics on the DIII-D tokamak

Abstract The optics system of the Electron Cyclotron Emission Imaging (ECEI) diagnostics on the DIII-D tokamak has been developed and installed for high-resolution temperature fluctuations measurement in the previous decade. The System-on-Chip approach upgrade was finished in June 2019 with high integrated receiver array with 20 individual modules. In this paper, we design new optics with high-level integration. In the new optics system, there will be two mirrors from plasma to receiver array, including one replaceable curved mirror out of the vacuum and one fixed curved mirror in the vessel. There are two options with 1:1 and 1:2 magnifications for high poloidal resolution and larger poloidal window modes. The new optics system has multiple improvements, including lighter weight, smaller size, more flexible installation and alignment. The synthetic ECEI module is used to evaluate the new optics system.