Visible and Infrared Optical Design for the ITER Upper Ports

Abstract

This document contains the results of an optical design scoping study of visible-light and infrared optics for the ITER 1 upper ports, performed by LLNL under contract for the US ITER Project Office. ITER is an international collaboration to build a large fusion energy tokamak with a goal of demonstrating net fusion power for pulses much longer than the energy confinement time. At the time of this report, six of the ITER upper ports are planned to each to contain a camera system for recording visible and infrared light, as well as other diagnostics. The performance specifications for the temporal and spatial resolution of this system are shown in the Section II, Functional Specifications. We acknowledge a debt to Y. Corre and co-authors of the CEA Cadarache report "ITER wide-angle viewing and thermographic and visible system" 2 . Several of the concepts used in this design are derived from that CEA report.The infrared spatial resolution for optics of this design is diffraction-limited by the size of the entrance aperture, at lower resolution than listed in the ITER diagnostic specifications. The size of the entrance aperture is a trade-off between spatial resolution, optics size in the port, and the location of relay optics. The signal-to-noise ratio allows operation at the specified time resolutions.3

Divertor IR thermography on Alcator C-Mod

“…Six of the upper ports are to hold periscope modules that view target sections that are displaced toroidally from the periscopes. An initial design 7 for this "top-viewing" system has been performed. C-Mod has recently upgraded its divertor IR thermography and its capabilities for measuring the divertor heat loads and heat-flux profiles on the targets.…”

Структура Поверхностного Слоя И Пропускание Света Сапфиром После Распыления В ВЧ Разряде В Смеси H-=sub=-2-=/Sub=--N-=sub=-2-=/Sub=-

“…Материаловедческие разработки, выполненные для ИТЭР, могут оказаться полезными и в других областях, например, в оптике и микроэлектронике [16], лазерной технике и приборостроении [17]. В качестве модельного материала ЛС используется при рассмотрении различных вопросов поверхностных явлений, таких как зарождение и рост металлических пленок на подложке [18], контактные явления при изготовлении сплавов Al/Al 2 O 3 [19,20], адсорбция [21], трение [22], пропускание и рассеяние света [23] и др.…”

Design status of ITER visible/IR outer strike point view

“…Using characteristics of currently available IR detectors, we calculated that a surface at 200°C emits enough IR radiation to provide a signal-to-noise ratio S/N = 256 (8 bits) at 86 kHz, using an optical design similar to this one [2]. This is significantly faster than the required 20 ms time resolution.…”

“…This is due to allowed sizes of the optics in the port tube, which constrain the size of the entrance aperture. Further information on the design is available in detailed technical reports [2,3].…”