Georges Charpak | Biography

Georges Charpak received the Nobel Prize in physics in 1992 for his invention and 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. Charpak is credited with creating instrumentation that is used by thousands of other scientists at CERN, the European laboratory for particle physics located in Geneva, Switzerland, as well as by researchers in other prominent laboratories involved 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 physicsat the Collège de France in Paris, Charpak went to work in the laboratory of physicist Frédéric Joliot-Curie. It was in this laboratory that Charpak began building the equipment he needed to perform his experiments (he constructed his own equipment out of necessity, as the laboratory had none). Charpak contends that he was not good at invention but had to learn in order to perform his experiments. 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 capture particle events. In 1958 Charpak was invited by experimental physicist Leon Lederman, who had heard Charpak lecture in Padua, to come to CERN to work on sparking devices to detect particles. Though these devices were an improvement over existing 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 the technology of the Geiger-Muller tube, bubble chamber, and 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 background in nuclear physics with the success of his invention.

Since liberating physics from dependence on film readings, Charpak has turned his 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 blades as 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 previously possible. He also is working on imaging problems to identify receptors in the brain.

Charpak's particle work mimics the state of the universe as it was a fraction of 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 predecessors with 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, and Carlo Rubbia led a group to discover the W and Z particles. (Charmed quarks and 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 married Dominique Vidal in 1953; they have two sons and one daughter. Some of Charpak's leisure interests include skiing, music, and hiking. He has been a member of the French Academy of Sciences since 1985. In addition to his continued association with CERN, Charpak is also the Joliot-Curie Professor at the Ecole Supérieure de Physique et Chimie in Paris, a position he has held since 1984. In 1989 he received the High Energy and Particle Physics Prize from the European Physical Society. He has published numerous papers in scientific journals.