Electron accelerators, in addition to important industrial applications, can be used to produce an impressive form of “art”. The acrylic block, 5 cm in diameter and 12.7 cm long, was placed in front of a beam of electrons from the I-10-1 (Industrial, 10MeV, 1kW) accelerator at the Whiteshell Laboratories. The energy of the electrons was chosen so that the beam penetrates roughly one-third the diameter of the cylinder before stopping and charging up the plastic. (This penetration is the “range of the electrons”).
Following the irradiation, which typically lasts several minutes, a sharp point, which is electrically grounded, is driven a short way into the plastic with a sharp blow from a grounded hammer and an electrical discharge, very similar to a lightning strike, occurs within the plastic. The discharge paths show up as damage to the plastic and produce the beautiful “trees” seen – each one is unique. The acrylic was then mounted in the wooden base that also houses a small-wattage bulb.
