A frequency modulated (FM) coherent laser radar (CLR) system is being designed for metrology and viewing of plasma-facing components in ITER. Soon after the fusion reactor begins operation, because of neutron activation of the reactor wall, the gamma radiation level inside the reactor will remain very high (estimated to be 3x10⁶ rad/hr, a day after shut-down). Each metrology campaign in ITER could last for times on the order of tens of hous. Since several such campaigns are anticipated during the life of ITER, radiation hardness in the 10⁸-10⁹ rad level is required of the metrology sensor components. Experimental information on radiation effects on components at such high dose level is very sparse, particularly for some of the special optical components required for the ITER CLR metrology system. We have tested the effect of radiation on a silica core polarization maintaining (PM) optical fiber, and TeO₂ crystals that are used in acousto-optic (AO) scanning devices, at doses up to ~10⁹ rad, using the High Flux Isotope Reactor (HFIR) facility at ORNL. The results of these tests will be described. Additional tests are planned for evaluating the performance of a complete AO scanning device. Anti-reflective coatings on optical lenses and prisms are also planned to be evaluated for radiation resistance. The progress made in these tests will also be described.

*Work supported by USDOE contract #DE-AC05-96OR22464