FREE ESSAY ON GEORGES CHARPAC

GEORGES CHARPAC

Georges Charpak
Georges Charpak, a French citizen, was born on August 1, 1924 in Poland. Charpak's family
moved from Poland to Paris when he was seven years old. During World War II Charpak
served in the resistance and was imprisoned by Vichy authorities in 1943. In 1944 he was
deported to the Nazi concentration camp at Dachau, where he remained until the camp was
liberated in 1945. Charpak became a French citizen in 1946. He received a Ph.D. in 1955
from the College de France, Paris, where he worked in the laboratory of Frederic
Joliot-Curie. In 1959 he joined the staff of European Laboratory for Particle Physics at
CERN in Geneva and in 1984 also became Joliot-Curie professor at the School of Advanced
Studies in Physics and Chemistry in Paris. 
Georges Charpak received the Physics Nobel Prize for 1992 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 path of particles issuing from high-energy collisions to be
tracked with a spatial precision of less than 1 mm. The measured coordinates along the
path of a charge particle passing through a magnetic field can be used to calculate the
particle's momentum. Additionally, 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 require the use
of intense beams and the sampling of a large number of events in a short period of time.

Georges Charpak built the first multiwire proportional chamber in 1968. Unlike earlier
detectors, such as the bubble chamber, which can record the tracks left by particles at
the rate of only one or two per second, the multiwire chamber records up to one million
tracks per second and sends the data directly to a computer for analysis. The speed and
precision of the multiwire chamber and its descendants, the drift chamber and the time
projection chamber, revolutionized high-energy physics. Samuel Ting's discovery of the
J/psi meson and Carlo Rubbia's discovery of the W and Z particles, which won Nobel Prizes
in 1976 and 1984, respectively, involved the use of multiwire chambers; and by the 1990s
such detectors were at the heart of almost every experiment in particle physics.
Charpak's chamber also has applications in medicine, biology, and industry. 
Indeed, Charpak's work helped pave the way for a greater incorporation of computers into
the data-acquisition process. At accelerators where millions of high-energy collisions
per second can occur and where vast amounts of data must be processed quickly, computers
are crucial. It is estimated, for example, that at the Super conducting Super Collider
some 40 trillion bytes of information per second will flow out of detectors monitoring
the proton-proton interactions taking place.