High-Accuracy Position Measurements with Drift Chambers and Proportional Chambers

By constructing multiwire drift chambers with a uniform electric field saturating the drift velocity, a perfectly linear response is obtained over all the chamber. The accuracy is close to ¿ = 100 ¿m. A similar accuracy is obtained for inclined tracks and in magnetic fields of the order of 1 tesla. By measuring the centre of gravity of avalanches a very high accuracy is obtained in the measurement of the two coordinates of avalanches in a single gap of a proportional chamber. The applications of the method to the mapping of spatial distributions of soft X-rays are discussed.