Update on the status of the ITER ECE diagnostic design

Authors: G. Taylor, M.E. Austin, A. Basile, J.H. Beno, S. Danani, R. Feder, S. Houshmandyar, A.E. Hubbard, D.W. Johnson, A. Khodak, R. Kumar, S. Kumar, A. Ouroua, S.B. Padasalagi, H.K.B. Pandya, P.E. Phillips, A.W. L. Rowan, J. Stillerman, S. Thomas, V. S. Udintsev, G. Vayakis, M. Walsh, D. Weeks

Abstract:  Considerable  progress has been made on the design of the ITER electron cyclotron emission (ECE) diagnostic over the past two years. Radial and oblique views are still included in the design in order to measure distortions in the electron momentum distribution, but the oblique view has been redirected to reduce stray millimeter radiation from the electron cyclotron heating system.  A major challenge has been designing  the 1000 K calibration sources and remotely activated mirrors located in the ECE diagnostic shield module (DSM) in the equatorial port plug #09. These critical systems are being modeled and prototypes are being developed. Providing adequate neutron shielding in the DSM while allowing sufficient space for optical components is also a significant challenge.  Four 45-meter long low-loss transmission lines transport the 70-1000 GHz ECE from the DSM to the ECE  instrumentation room.  Prototype  transmission lines  are being tested,  as are the polarization splitter modules that separate O-mode and X-mode polarized ECE. A highly integrated prototype 200-300 GHz radiometer is being tested on the DIII-D tokamak in the USA.  Design  activities also include integration of ECE signals into the ITER plasma control system and determining  the hardware  and software architecture needed to control and calibrate the ECE instruments.
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