This is a cross section of a magnet from a nuclear Accellerator at the University of California at Berkeley. It is embedded in plastic for display purposes. My father was Director of the Lawrence Radiation Lab at Berkeley from 1958 until his retirement in the 1970s. He collected quite an array of odd memorabilia of nuclear technology. When we cleaned out his office after his retirement, the University sent along a representative to check things for radioactivity. A coupld of items had to be whisked away! This one was fine though.