Scenery and Science in a Physics Wonderland
Bubble Chamber Parking Lot
Pull into a parking space and let me tell you about the Bubble Chamber.
[2 SECOND PAUSE]
This bubble chamber was commissioned in 1973, making it the largest liquid hydrogen bubble chamber in the world at the time. The liquid hydrogen was kept at negative 423 degrees Fahrenheit, and the chamber was wrapped in an impressive 150-ton superconducting magnet made by Fermilab and nearby Argonne Lab. A gigantic piston, six feet across, kept the liquid hydrogen under pressure. At a signal from the Control Room, that piston would drop more than four inches in about 60/1000ths of a second, lowering the pressure on the Chamber and expanding the liquid. The effect of the expansion was similar to shaking a soft drink; bubbles would appear in many places, but it also made the paths of the particles that had passed through the Chamber visible. Cameras mounted in the top of the chamber took pictures of those tracks, sometimes snapping more than 10,000 in a single day. People called “scanners” would analyze the film and pick out the important neutrino interactions.