title: New compact and efficient local oscillator optic system for the KSTAR electron cyclotron emission imaging system.
abstract: Electron cyclotron emission imaging (ECEI) diagnostic on Korean Superconducting Tokamak Advanced Research utilizes quasi-optical heterodyne-detection method to measure 2D (vertical and radial) Tefluctuations from two toroidally separated poloidal cross section of the plasma. A cylindrical lens local oscillator (LO) optics with optical path length (OPL) 2-2.5 m has been used in the current ECEI system to couple the LO source to the 24 vertically aligned array of ECE detectors. For efficient and compact LO optics employing the Powell lens is proposed so that the OPL of the LO source is significantly reduced from ∼2.0 m to 0.4 m with new optics. The coupling efficiency of the LO source is expected to be improved especially at the edge channels. Results from the optical simulation together with the laboratory test of the prototype optics will be discussed in this paper.
authors.affiliation: Department of Physics, Pohang University of Science and Technology, Pohang 37673, South Korea.
authors.forename: Y B
authors.initials: YB
authors.lastname: Nam
authors.affiliation: Ulsan National Institute of Science and Technology, Ulsan 44919, South Korea.
authors.forename: D J
authors.initials: DJ
authors.lastname: Lee
authors.affiliation: Ulsan National Institute of Science and Technology, Ulsan 44919, South Korea.
authors.forename: J
authors.initials: J
authors.lastname: Lee
authors.affiliation: Pennsylvania State University, Old Main, State College, Pennsylvania 16801, USA.
authors.forename: C
authors.initials: C
authors.lastname: Kim
authors.affiliation: Department of Physics, Pohang University of Science and Technology, Pohang 37673, South Korea.
authors.forename: G S
authors.initials: GS
authors.lastname: Yun
authors.affiliation: Ulsan National Institute of Science and Technology, Ulsan 44919, South Korea.
authors.forename: W
authors.initials: W
authors.lastname: Lee
authors.affiliation: Ulsan National Institute of Science and Technology, Ulsan 44919, South Korea.
authors.forename: H K
authors.initials: HK
authors.lastname: Park