A SPECTRAL ANALYSIS LINK INCLUDING AN INNOVATIVE FIBER OPTIC VACCUM FEEDTHROUGH FOR PLASMA DIAGNOSTICS FOR THE INTERNATIONAL THERMONUCLEAR EXPERIMENTAL REACTOR

DOE CURRENTLY PARTICIPATES IN PLANNNING THE DEVELOPMENT OF A DEMONSTRATION FUSION DEVICE KNOWN AS THE INTERNATIONAL THERMONUCLEAR EXPERIMENTAL REACTOR (ITER). IN ORDER TO ACHIEVE THE OBJECTIVES OF DEVELOPING A PHYSICS AND TECHNOLOGY BASE FOR ITER DESIGN, VERY RELIABLE AND DETAILED MEASUREMENT TECHNIQUES FOR MONITORING PLASMA BEHAVIOR DURING ALL PHASES OF OPERATION ARE REQUIRED. AMONG THE MANY DIAGNOSTIC TECHNIQUES USED TO MONITOR SPECIFIC PLASMA PARAMETERS IS OPTICAL SPECTROSCOPY. ONE PROBLEM WITH IMPLEMENTING OPTICAL TECHNIQUES IS THE COLLECTION OF LIGHT AND ITS DELIVERY TO REMOTE SPECTRAL ANALYSIS EQUIPMENT OUTSIDE THE REACTOR. PRESENTLY, OPTICAL FIBERS ARE BEING INVESTIGATED FOR VISIBLE SPECTROSCOPY OF THE PLASMA BECAUSE OF THEIR FLEXIBILITY IN DELIVERING OPTICAL SIGNALS. IN ORDER TO UTILIZE FIBER OPTICS TECHNOLOGY IN THE ITER REACTOR, BOTH RADIATION-HARD COLLECTION OPTICS AND HIGH RELIABILITY FIBER OPTIC VACUUM FEEDTHROUGHS ARE REQUIRED THAT CAN WITHSTAND THE HARSH FUSION ENVIRONMENT OF THE ITER. SIMPLE FIBER OPTIC COMPONENTS INTEGRAL TO RADIATION HARDENED FIBERS WILL BE DEVELOPED IN PHASE I TO DEMONSTRATE A FIBER OPTIC SPECTRAL ANALYSIS LINK THAT PROMISES TO MEET DIAGNOSTIC REQUIREMENTS OF ITER. THE PLANNED FIBER OPTIC ELEMENTS CAN BE USED BOTH FOR SENOSR ELEMENTS WITH HIGH SPATIAL RESOLUTION AND AS COMPONENTS IN A MULTICHANNEL FIBER OPTIC FEEDTHROUGH CAPABLE OF OPERATING AT TEMPERATURES ABOVE 450 DEGREES CENTIGRADE AND PRESSURES LESS THAN 10(-11) TORR.