title: Development of imaging bolometers for magnetic fusion reactors (invited).
abstract: Imaging bolometers utilize an infrared (IR) video camera to measure the change in temperature of a thin foil exposed to the plasma radiation, thereby avoiding the risks of conventional resistive bolometers related to electric cabling and vacuum feedthroughs in a reactor environment. A prototype of the IR imaging video bolometer (IRVB) has been installed and operated on the JT-60U tokamak demonstrating its applicability to a reactor environment and its ability to provide two-dimensional measurements of the radiation emissivity in a poloidal cross section. In this paper we review this development and present the first results of an upgraded version of this IRVB on JT-60U. This upgrade utilizes a state-of-the-art IR camera (FLIR/Indigo Phoenix-InSb) (3-5 microm, 256 x 360 pixels, 345 Hz, 11 mK) mounted in a neutron/gamma/magnetic shield behind a 3.6 m IR periscope consisting of CaF(2) optics and an aluminum mirror. The IRVB foil is 7 cm x 9 cm x 5 microm tantalum. A noise equivalent power density of 300 microW/cm(2) is achieved with 40 x 24 channels and a time response of 10 ms or 23 microW/cm(2) for 16 x 12 channels and a time response of 33 ms, which is 30 times better than the previous version of the IRVB on JT-60U.
authors.affiliation: National Institute for Fusion Science, Toki 509-5292, Japan.
authors.forename: Byron J
authors.initials: BJ
authors.lastname: Peterson
authors.forename: Homaira
authors.initials: H
authors.lastname: Parchamy
authors.forename: Naoko
authors.initials: N
authors.lastname: Ashikawa
authors.forename: Hisato
authors.initials: H
authors.lastname: Kawashima
authors.forename: Shigeru
authors.initials: S
authors.lastname: Konoshima
authors.forename: Artem Yu
authors.initials: AY
authors.lastname: Kostryukov
authors.forename: Igor V
authors.initials: IV
authors.lastname: Miroshnikov
authors.forename: Dongcheol
authors.initials: D
authors.lastname: Seo
authors.forename: T
authors.initials: T
authors.lastname: Omori