The beer experiment that won the noble prize for particle physics.

Late one night in 1953, Donald Glaser smuggled a case of beer into his University lab. He wanted to test out the limitations of his revolutionary invention: the bubble chamber.

Previously, Glaser had only tried exotic chemical liquids in his device. But now his sense of experimental adventure had been galvanized by a recent victory over the great and famously infallible physicist Enrico Fermi.

Fermi, who had invited Glaser to Chicago to find out more about his invention, had already seemingly proved that a bubble chamber could not work. But when Glaser found a mistake in Fermi’s authoritative textbook, he dedicated himself to redoing the calculations.

Glaser found that, if he was correct, that the bubble chamber should work with water. To make absolutely certain he “wasn’t being stupid”, Glaser conducted this curious nocturnal experiment at his Michigan laboratory. He also discovered that the bubble chamber worked just as well when using lager as it had with other chemicals.

There was one practical issue however, the beer caused the whole physics department to smell like a brewery. “And this was a problem for two reasons,” Glaser recalled. “One is that it was illegal to have any alcoholic beverage within 500 yards of the university. The other problem was that the chairman was a very devout teetotaler, and he was furious. He almost fired me on the spot”.

On 1st August 1953, 60 years ago this Thursday, Glaser published his famous paper on the bubble chamber – strangely failing to mention the beer experiment.

Glaser’s device provided a very effective way to detect and visualise particles. It consisted of a tank of pressurised liquid, which was then superheated by reducing the pressure. Charged particles passing through the tank stripped electrons from atoms in the liquid and caused the liquid to boil. Bubbles created from the boiling liquid revealed the particle’s path through the liquid.

Particle tracks produced by Gargamelle indicating the discovery of the neutral currents, 1973. Credit: CERN
Particle tracks produced by Gargamelle indicating the discovery of the neutral currents, 1973. Credit: CERN

One of Glaser’s motivations for his invention was to avoid having to work with large groups of scientists at big particle accelerators. Instead, he hoped his device would enable him to study cosmic rays using cloud chambers in the traditional fashion; up a mountain, ski in the day, “and work in sort of splendid, beautiful surroundings. A very pleasant way of life – intellectual, aesthetic, and athletic”

Ironically, as the bubble chamber only worked with controlled sources of particles, it was inherently suited to accelerator research, not cosmic rays. Soon the large accelerator facilities built their own, massive bubble chambers.

Design drawings for CERN’s Gargamelle bubble chamber. Credit: CERN
Design drawings for CERN’s Gargamelle bubble chamber. Credit: CERN

Between 1965-1970 CERN built Gargamelle – a bubble chamber of such proportions that it was named after a giantess from the novels of Francois Rabelais (not the Smurfs’ villain). Gargamelle proved a huge success, enabling the discovery of neutral currents – a crucial step in understanding how some of the basic forces of nature were once unified.

A bubble chamber is a vessel filled with a superheated transparent liquid ( when a liquid is heated at a temperature more than its boiling point ) most often liquid hydrogen is used to detect electrically charged particles moving through it. It was invented in 1952 by Donald A. Glaser, for which he was awarded the 1960 Nobel Prize in Physics. Supposedly, Glaser was inspired by the bubbles in a glass of beer; however, in a 2006 talk, he refuted this story, although saying that while beer was not the inspiration for the bubble chamber, he did experiments using beer to fill early prototypes.

A bubble chamber is a vessel filled with a superheated transparent liquid (when a liquid is heated above its boiling point) most commonly liquid hydrogen is used to detect electrically charged particles moving through it. The invention was made by Donald A. Glaser in 1952, and he was awarded the 1960 Nobel Prize in Physics for it. According to legend, Glaser was inspired by the bubbles in beer; however, in a 2006 talk, he refuted that story, although he did experiment with beer to fill early prototypes.

In normal cases, a bubble chamber consists of a large cylinder filled with a liquid that has been heated just below its boiling point. A piston decreases the pressure of a liquid as particles enter it, and the liquid enters a metastable, superheated state (The least energetic state where the nucleus is highly stable). Charged particles create an ionization track ( Due to the superheated liquid entering the chamber that liquid leaves its track mark by evaporating the liquid that came in its track ), around which the liquid vaporizes, forming microscopic bubbles. Bubble density around a track is proportional to a particle’s energy loss.
This means If you see more bubbles it clearly shows that the system had lost more energy )

Bubbles grow in size as the chamber ( Vassel ) expands until they are large enough to be seen or photographed. Several cameras are mounted around it, allowing a three-dimensional image of an event to be captured. Bubble chambers with resolutions down to a few micrometers (μm) have been operated.

For Pro’s :-

Figures 38-9 and 38-10 are convincing evidence of the wave nature of matter. Still, we have countless experiments that suggest its particle nature.

Figure 38-11, for example, shows the tracks of particles (rather than waves) revealed in a bubble chamber. When a charged particle passes through the liquid hydrogen that fills such a chamber, the particle causes the liquid to vaporize along the particle’s path. A series of bubbles thus marks the path, which is usually curved due to a magnetic field set up perpendicular to the plane of the chamber.

In Fig. 38-11, a gamma-ray left no tracks when it entered at the top because the ray is electrically neutral and thus caused no vapor bubbles as it passed through the liquid hydrogen. However, it collided with one of the hydrogen atoms, kicking an electron out of that atom; the curved path taken by the electron to the bottom of the photograph has been color-coded green. Simultaneous with the collision, the gamma-ray transformed into an electron and a positron in a pair production event (see Eq. 21-15). Those two particles then moved in tight spirals (color-coded green for the electron and red for the positron) as they gradually lost energy in repeated collisions with hydrogen atoms. Indeed these tracks are evidence of the particle nature of the electron and positron, but is there any evidence of waves in Fig. 38-11?

To simplify the situation, let us turn off the magnetic field so that the strings of bubbles will be straight. We can view each bubble as a detection point for the electron. Matter waves traveling between detection points such as I and F in Fig. 38-12 will explore all possible paths, a few of which are shown. Generally, for every path connecting I and F (except the straight-line path), there will be a neighboring path such that matter waves following the two paths cancel each other by interference. For the straight-line path joining I and F, matter waves traversing all neighboring paths reinforce the wave following the direct path. You can think of the bubbles that form the track as a series of detection points at which the matter-wave undergoes constructive interference.

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