Magnetic Air Gap Research Articles

The Nottingham cosmic-ray spectrometer-I

Measurements of the sea-level μ-meson momentum spectrum made during the last decade utilizing conventional air gap spectrometers have indicated that the differential intensity is approximately proportional to 1/(momentum)3. For a study of the high-momentum region therefore, the instrument concerned not only must have a high angular resolution but also be able to accumulate data at a significant rate. These requirements can only be met with difficulty when conventional air gap magnets are used. This paper is concerned with the characteristics of a μ-meson spectrometer in which the air gap magnet is replaced by a block of lagnetized iron. Methods are given for computing the effects of energy loss and scattering in the material and it is shown that the angular scattering distribution produced by the iron in the unmagnetized state can be accurately predicted. Further since the magnetic material acts as a filter for nuclear active particles this type of instrument has all the advantages of operating underground while retaining the convenience of working at sea-level.

Experiments on the Design of Synchrotron Magnets

An important aspect of the problem of synchrotron magnet design is that of obtaining a given magnetic energy in the guide field with the minimum expenditure of iron, copper, and condensers. Tests were made on d.c. magnet models of several configurations, using as criteria (1) the ratio of the peak energy in the useful portion of the magnet air gap to the peak energy which must be stored in the condensers, and (2), the ratio of magnetic flux in the gap to the flux in the return path of the magnetic circuit. Comparative performance data are tabulated. The method of shaping the pole faces to obtain the desired fall-off of B with r over the greatest range in r is discussed, and a shape worked out by trial and error is given.