| 摘要 |
<p>The screen is located on walls etc. to minimise the amt. of diffused radiation reaching the walls, and absorbs direct or diffused radiation. The screen pref. consists of cavities designed to trap diffused rays, esp. where the screen forms a honeycomb or grid of cavities. The screen is formed esp. by a grid of metal strips, where the edges of the strips face a source of radiation and thus form a min. surface area exposed directly to the source. The grid forms numerous cavities, and pref. has chamfered strip edges facing the source of radiation. The interior of each cavity pref. has numerous facettes which scatter the radiation. Used esp. on the internal surfaces of a chamber or structure contg. a source of gamma or X-rays.</p> |
