X-ray beam through cloud chamber shown on TV camera

X-ray beam through cloud chamber shown on TV camera. An X ray tube is next to a diffusion cloud chamber within a lead-lined box with lead plastic windows to protect viewers. When a high voltage (40 kV pulsating DC from an induction coil) is placed across the terminals of the X ray tube, X rays are sent through a hole in a lead plate into the cloud chamber, through the 'sensitive layer'. The X rays knock electrons off molecules of oxygen and nitrogen in the air, creating positively and negatively charged ions. Supercooled methanol vapor in the cloud chamber begins condensing on the ions, producing trails of droplets that scatter light, making the path of the beam of X rays visible. A TV camera displays this on a monitor. Ref.:Physics For Scientists and Engineers by Giancoli, 2nd ed., p. 985