Georges Charpak received the Nobel Prize in physics in 1992 for his inventionand development of particle detectors, most notably the multiwire proportional chamber. A number of his colleagues, who received the Nobel Prize before him, had used his invention to make important discoveries in physics. Charpakis credited with creating instrumentation that is used by thousands of otherscientists at CERN, the European laboratory for particle physics located in Geneva, Switzerland, as well as by researchers in other prominent laboratoriesinvolved in the study of the nature of matter.
Born on August 1, 1924, in Dabrovica, Poland, to Maurice Charpak and Anna Szapiro, Charpak moved to France with his family in 1929. In 1943 the French Vichy government accused the young Charpak of being a terrorist and sentenced him to the concentration camp in Dachau, West Germany (now Germany). Charpak remained in the camp until its liberation in 1945. Upon his return to France, he completed a degree in civil engineering from the Ecole des Mines in Paris,and in 1946 he became a French citizen.
Two years later, as a graduate student in nuclear physics at the Collège de France in Paris, Charpak went to work in the laboratory of physicist Frédéric Joliot-Curie. In this laboratory Charpak began buildingthe equipment he needed to perform his experiments (he constructed his own equipment out of necessity, as the laboratory had none). In 1955 he received his Ph.D. from the Collège de France.
In awarding the Nobel Prize to Charpak, the Swedish Academy of Sciences traced the history of the development of detector devices in physics. The cloud chamber and the bubble chamber were two earlier inventions that had received recognition from the academy. Both relied on photographic techniques to captureparticle events. In 1958 experimental physicist Leon Lederman, who had heardCharpak lecture in Padua, invited Charpak to come to CERN to work on sparking devices to detect particles. Though these devices were an improvement overexisting techniques, they, too, relied on photographic recording, which was slow and cumbersome to analyze. Charpak turned to the problem of a spark chamber reading without photographic film, and built his first multiwire proportional tracking chamber in 1968. The multiwire proportional chamber extended thetechnology of the Geiger-Muller tube, bubble chamber, and cloud chamber in two ways: The multiwire proportional chamber replaced the single positively charged wire of the Geiger-Muller tube, which attracts electrons in a chamber of ionized gas, with a multiwire device; it also replaced photographic analysis of a trail of bubbles with computerized electronic analysis of current produced in the wires as they attract electrons. Charpak credited his backgroundin nuclear physics with the success of his invention.
Since liberating physics from dependence on film readings, Charpak has turnedhis interests to medicine and aerospace problems. Work he has done in the latter area makes it possible to produce an X-ray radiograph of turbine bladesas they spin. In the field of medicine, his chamber is able to analyze the structure of a protein with X rays a thousand times faster than was previouslypossible. He also is working on imaging problems to identify receptors in thebrain.
Charpak's particle work mimics the state of the universe as it was a fractionof a second after the Big Bang. It is believed that some of the particles have not existed in nature since that time, and the ability of physicists to study them will reveal and increase the understanding of the relationships among the forces of nature. Whereas Charpak built on the work of his predecessorswith the bubble and spark chambers, others have used his invention to make their own contributions to the field of physics. A group led by Samuel Ting discovered the first manifestation of charmed quarks at Brookhaven in 1974, andCarlo Rubbia led a group to discover the W and Z particles. (Charmed quarksand W and Z particles are subatomic particles.)
Charpak has worked on behalf of other scientists imprisoned by repressive governments. He is the founder of the SOS committee at CERN. This association worked diligently on the part of Soviet dissidents, such as Andrei Sakharov, Yuri Orlov, and Anatoly Sharansky, when they were deprived of their civil rights under the former Soviet Union.
Charpak has been a member of the French Academy of Sciences since 1985. Charpak retired from active research at CERN in 1991 after a long and distinguished career there. He was also the Joliot-Curie Professor at the Ecole Supérieure de Physique et Chimie in Paris for many years beginning in 1984. In1989 he received the High Energy and Particle Physics Prize from the EuropeanPhysical Society. He has published numerous papers in scientific journals, and in 2001 published a book he cowrote, Megawatts and Megatons: A TurningPoint in the Nuclear Age?
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