Abstract: A reflecting optical dosimeter for measuring radiation exposure made of a in block of radiation sensitive optical material which darkens upon exposure to ionizing and nuclear radiation. The block has an input light pipe at one corner and an output light pipe at another corner, arranged so that the light follows a path including several reflections off of the edges of the block to thereby greatly extend the length of the path. One corner of the block is formed at an angle so that after the light is reflected several times between two opposite edges, it strikes the angled corner and is then reflected between the other two edges before exiting at the output light pipe. The decreased transmission of light from the input to the output pipe is a measure of the radiation dose.

Abstract: A light shield for selectively shielding light-sensitive elements in a semiconductor device from incident light comprises an opaque layer of material which is substantially nonreflective to light such as, for example, blackened photoresist, blackened metal, or a plastic containing particles of black carbon.