Interior of a device used to irradiate plastic tubing with an electron beam. Certain plastics become cross-linked" (structurally altered) when bombarded with an electron beam. Cross-linked plastics have increased flexibility and durability. They are less prone to tears or leaks & tend to stretch, rather than melt, when heated. These properties are desirable in numerous packaging applications - in "shrink-wrapped" foodstuffs, for example. Electron beams provide a more safe & convenient source of radiation than radioactive isotopes, since they may be quickly switched off & are not spilled or accidently ingested. Photo taken at Raychem, California, USA."