Ultra-High Speed Thermal Imaging of the Plasma-Facing Surfaces NSTX

72260S03-I The thermal imaging of plasma-facing surfaces, used in magnetic fusion experiments, could be valuable for understanding the physics of power loss processes and for assuring that wall surface temperatures remain below failure limits. In particular, recent concerns have been raised about the potentially damaging effect of highly transient ELMs (Edge Localized Modes) and other transient events (e.g., disruptions) on the first wall of the ITER (International Thermonuclear Experimental Reactor) experiment. Such transient heat loads can rapidly increase wall surface temperature, leading to increased impurity influx, radiation, and erosion of the wall. This problem is further complicated by the irregular nature of these wall surfaces, which can lead to localized ¿hot spots¿ (e.g., due to tile edges or co-deposited layers that form ¿flakes¿). Knowledge of the thermal response of the wall during ELMs and other transient events is important for the successful design of in-vessel components for ITER. This project will develop an infrared sensitive, ultra-high-frame-rate camera that will provide two-dimensional (area) measurements of wall surface temperature fluctuations, with temporal resolution in microseconds, that can be interpreted in terms of plasma energy deposition on the wall. In Phase I, the diagnostic requirements for the IR camera will be further clarified, and a preliminary design of an ultra-high-frame-rate CCD image sensor will be prepared. The device will be completed, built, and evaluated in Phase II. Commercial Applications and Other Benefits as described by awardee: There are no two-dimensional infrared cameras commercially available that are capable of frame rates between 10,000 and 1,000,000 frames per second. An ultra-high-frame-rate infrared television camera should have direct application as a diagnostic in magnetic fusion research.