Bi-directional reflectance distribution function of a tungsten block for ITER divertor

Iwamae, Atsushi*; Ogawa, Hiroaki; Sugie, Tatsuo; Kusama, Yoshinori

In order to investigate reflection properties on plasma-facing material in ITER, the bi-directional reflectance distribution function (BRDF) of a tungsten block sample has been measured. On the machining surface of the block, one-directional machining lines are engraved. Two laser diodes 652 nm and 473 nm were used to simulate H and H emissions, respectively. The reflected light is affected by the machining surface. The reflected light traces a line when the incident light is injected in the perpendicular direction to the engraved line. On the other hand the reflected light traces an arc shape when the incident light is injected in the parallel direction to the engraved lines. Ray tracing simulation qualitatively explains the experimental results.