Charpak, Georges (1924– )

Polish-born French physicist who was awarded the Nobel Prize for Physics in 1992 for his invention and development of particle detectors, in particular the multiwire proportional chamber (consisting of an array of wires, each at a high voltage, that produce an electrical signal as a particle passes through).

The multiwire proportional chamber Modern elementary-particle physicists look deep inside matter using accelerators as microscopes. These accelerators produce showers of particles, like the sparks from fireworks, which can be discharged a hundred million times each second. Inside the particle shower there is information about the smallest constituents of matter – the elementary particles – and the forces with which they interact. However, it takes a special kind of detector to extract this information. A suitable detector must be able to react quickly, track the paths of particles and send its observations direct to a computer. These requirements are met by the multiwire proportional chamber which Charpak invented in 1968.

In a multiwire chamber, thousands of wires cross the space traversed by the particles. When a particle passes through the chamber, electrical signals are produced in the wires. A computer connected to the wires then maps the path of each particle and displays it on a monitor screen. This type of detector is used, in some form or other, in almost all elementary particle physics experiments today. It is also used in medicine and industry.

Life Charpak was born at Dabrovica, Poland, and became a naturalized French citizen in 1946. He was educated in Paris and received his doctorate in 1954 for work in experimental nuclear physics. From 1959 he worked at CERN, the European particle physics laboratory near Geneva, Switzerland.