Monday, December 19, 2022

Brookhaven National Laboratory's 80" Bubble Chamber and Omega-Minus Particle

Michel Talbot posted
Control room of the Brookhaven 80-inch [6.7', 2m] Liquid Hydrogen Bubble Chamber showing some of the many instruments and controls required to monitor and precisely regulate the operation of the large, complex components and systems. Brookhaven National Laboratory, Upton, New York. 1963
The bubble chamber is a vessel filled with superheated transparent liquid hydrogen used to detect high-energy charged particles moving through it. Particle accelerator facilities like the Alternating Gradient Synchrotron (AGS) used bubble chambers extensively in the past, however they have now mostly been supplanted by wire chambers, spark chambers, drift chambers, and silicon detectors. The most significant discovery made with Brookhaven’s 80-inch chamber came in the first few months of its operation: the detection of the Ω⁻ particle, whose existence had been predicted by theoretical physicist Murray Gell-Mann. This finding supported the first attempt by physicists to organize the increasingly long list of subatomic particles into an orderly pattern, similar to that used to arrange elements in the periodic table.
Joe Rando: I worked there in the early to mid-1980s and there were still older women analyzing photographs from bubble chambers. I’m not sure is they were recently produced or from years back being given a fresh look.
Michel Talbot: Joe Rando It could be recently produced. The Big European Bubble Chamber (BEBC) for example was operational from 1977 to 1984. Even after 1984 it would have taken many years to plow through the huge backlog of 6.3 million 3D bubble chamber photographs of the 22 experiments at CERN. I'm not sure when the Brookhaven 80-inch chamber was decommissioned though.
Paul Napier: Thanks for posting this. I worked in that facility after the 80" Bubble Chamber was shut down, salvaging parts. Later worked on the 7' [2.1m] Bubble Chamber, 1975-1978. [That is just 4" larger than the 80" chamber. I wonder what else was different because size change doesn't seem to be significant.]
Phillip Rulon: I worked at the AGS in the 1980s. I’ll never forget the beam horn that sounded each time the ring emptied out into the experimental areas. It was a haunting sound, almost like a howl of a wild animal.
Alan Nebola: I spent a couple years working at the Fermilab 15’ [4.6m] Bubble Chamber. That was in 1979-1981. I started out at Internal Target group working for Peter McIntyre working on a antiproton storage ring and then moved to the bubble chamber

Michel commented on his post
The 80-inch Liquid Hydrogen Bubble Chamber. The stainless steel chamber (2 m long x 0.66 m high x 0.69 m deep), which contains 900 L of liquid hydrogen at a temperature of -248 C, is surrounded by a vacuum chamber, large magnet coils, and a massive steel magnet yoke. The magnet, which requires 4 MW of electrical power, provides a uniform magnet field throughout the chamber of 2 T. The magnet and vacuum chamber can be opened to provide access to the chamber. The entire 408 tonne chamber and magnet assembly can be translated, rotated, and elevated as required by the experimental program.One side of the chamber consists of a glass window 0.17 m thick through which the chamber is illuminated and photographed. As a pulse of highly energetic particles from the Alternating Gradient Synchrotron are guided magnetically into the chamber, the liquid hydrogen is superheated by a sudden reduction in pressure. The charged particles entering the chamber or produced in the chamber by nuclear interactions between the bombarding particles and the hydrogen nuclei (protons) cause the superheated liquid hydrogen to boil, leaving a track of tiny bubbles to mark their paths. The magnetic field in the chamber deflects the charged particles and causes them to move in curved paths.By measuring the curvature, length, and density of the tracks, scientists can determine the electric charge, momentum, mass, and other properties of the particles. The light source for illuminating the chamber and the three automatic cameras which photograph the tracks are located on the lower gallery. A technician is seen removing one of the cameras. Vacuum equipment, as well as the chamber expansion system, are located on the upper gallery and on top of the chamber. The hydraulic ram which moves the chamber is shown at the lower left.

Michel commented on his post
Inside the tunnel of the Alternating Gradient synchrotron (AGS) at the conjunction of the linear accelerator (Linac) with the main magnet enclosure. The proton beam emerges from the Linac, which is located behind the two unidentified men (left rear) and travels along the 4-inch pipe to the lower right, passing through a series of focusing lenses and steering magnets into the orbit of the synchrotron magnet ring, part of which can be seen on the right. The pipe extending across the aisle to the left is the exit pipe from an analyzer magnet which bends the proton beam through 25 degree in order to allow for determination of the energy spread of the protons.
Evan Jones: Michel Talbot Got a tour of the ring when the AGS was shut down many years ago thanks to a friend of mine who worked there. Just amazing! I remember him saying the the AGS was the biggest consumer of power on Long Island with the exception of the Long Island Railroad!

Michel commented on his post
This is where all those little protons begin their perilous journey, a 50 MeV LINAC (linear accelerator) pre-accelerates them before injection into the AGS merry-go-round ring.

Michel commented on his post
The AGS's Cockroft-Walton generator, used to provide the initial acceleration to protons prior to injection into the 50 MeV LINAC and then on to the AGS booster.

Michel commented on his post
This gas storage vessel was once used as the "safety sphere" associated with the 80-inch bubble chamber. It was designed to contain the hydrogen gas that would be vented from the bubble chamber in the event of an emergency.

Michel commented on his post
Bubble chamber picture of the first observed omega-minus particle --discovered in 1964 by a team of physicists from Brookhaven, the University of Rochester and Syracuse University, led by Nicholas Samios of Brookhaven, using the 80-inch bubble chamber at the AGS.

Martin Walsh commented on Michel's post
I love the little doll hanging from the clock!
Jim Williams: It looks like one of the little troll dolls that were popular in the 60s. My sister and I had a few.

AmericanHistory, 1 of 7 photos
"Object EM.N-10118 is the chamber proper of the Brookhaven 80" hydrogen bubble chamber."
[This page has a history about detection chambers.]
The Brookhaven 30bev AGS was started in 1960.
"The bubble chamber is made of a non-magnetic stainless steel. A piston in the cylinder above expanded and compressed the liquid hydrogen once per second; it was cycled, and photographed, more than ten million times in the decade it was in operation....The flat glass window, 6 inches thick and weighing 1500 pounds, was, when made, the largest piece of optical quality glass....Fifty physicists, engineers, and technicians kept the chamber operating 24 hours a day....These six- and seven-foot bubble chambers of the early 1960s, containing some 200 gallons of liquid hydrogen, were succeeded towards the end of the decade by a generation of 3,000 to 10,000-gallon, barrel-shaped chambers. Of these there were only four; one each at Argonne National Laboratory near Chicago, at Brookhaven National Laboratory, at CERN in Switzerland, and at Fermi National Accelerator Laboratory, also near Chicago. Their leading role in elementary particle physics later passed to complex electronic detectors."

"The discovery of the omega baryon was a great triumph for the quark model of baryons because it was searched for and found only after its existence, mass, and decay modes were predicted by the quark model. It was discovered at Brookhaven in 1964. "

Since I can't remember the Standard Model, a found a copy for reference.
abc, Wikimedia Commons: Miss J

1 comment:

  1. You have explained a complex machine/process so it is understandable to the "Common Man"(?). When I first saw it I thought "no way", then I read the second paragraph. Then the rest of the article. I understand physics? Of course not, but I sort of understand how an experiment works mechanically. Thank you.