INFLUENCE OF HIGH-INTENSITY RADIATION ON THE PROPERTIES OF OPTICS FOR FUSION DIAGNOSTICS

Diagnostic instruments for future fusion devices such as ITER and BPX will contain optical components that must retain their transmissive (or reflective) ability in intense radiation fields. Several studies of the behavior of such components have been conducted using the University of Illinois TRIGA nuclear research reactor. Candidate materials (e.g. fused silica, sapphire, single and polycrystal CsI) were selected for testing to cover a broad range of the electromagnetic spectrum (near ultraviolet to the far infrared). Two key phenomena relative to the employment of transmissive components for future diagnostics were studied: the decrease in optical/IR transmission and the emission of radioluminescence, as a function of the dose rate and dose received, both for short (ms) transients and for longer steady-state operation.