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Physics News Update
Number 99 (Story #1), October 14, 1992 by Phillip F. Schewe and Ben Stein

THE PHYSICS NOBEL PRIZE FOR 1992 GOES TO GEORGES CHARPAK for his numerous contributions to the instrumentation used in experiments at high-energy accelerators. Many of the new particles discovered in the past few decades have used detectors developed or greatly improved by Charpak. In particular, his development of the multiwire proportional chamber in the 1960's allowed the trajectories of particles issuing from high- energy collisions to be tracked with a spatial precision of less than 1 mm. (The measured coordinates along the trajectory of a charge particle passing through a magnetic field can be used to compute the particle's momentum.) Furthermore, the rate at which the chamber could make a measurement, recover, and then be able to make a new measurement grew to be many thousands per second. These characteristics of Charpak's detector---high spatial resolution and high repetition rate---were particularly important in the study of rare interactions or the creation of short-lived exotic particles which often necessitate the use of intense beams and the sampling of a large number of events in a short period of time. (For a typical account, see the article about the discovery of the Z particle in the March 1982 issue of Scientific American.) Indeed, Charpak's work helped pave the way for a greater integration of computers into the data-acquisition process. At accelerators where millions of high-energy collisions per second can occur and where colossal amounts of data must be processed quickly, computers are essential. It is estimated, for example, that at the Superconducting Super Collider some 40 trillion bytes of information per second will flow out of detectors monitoring the proton-proton interactions taking place. (Computers in Physics, Sep/Oct 1992.) Charpak, a Fench citizen, has spent much of his career at the CERN lab in Geneva. He was born in 1924 in Poland and received a PhD in 1955 from the Collge de France in Paris.