The acceleration of charged particles to very high energies

More experimental information about the nature of the binding forces between nuclear constituents is necessary before an advance in fundamental nuclear physics can be achieved. By considering the type of information which would be most useful, the conclusion is reached that it necessary to have available protons of energies of about 1000 MeV. in order to carry out the necessary experiments. It is with a method of obtaining protons of this energy that this paper is concerned. An examination of the possibilities of achieving such high energy protons by the existing methods leads to a pessimistic conclusion, and a new method is suggested. This new method, the synchrotron, is described in principle, and its advantages are outlined, a very important factor being its comparatively low cost. An accelerator of this type is being built at Birmingham University with a grant from the Department of Scientific and Industrial Research, and its design is considered in some detail. The magnet and its excitation form the greatest part of the apparatus in size and cost. Several alternative methods are suggested and discussed for both the magnet design and its method of excitation. An air-cored magnet is considered but rejected because of the very large mechanical forces involved and the precision required in positioning the conductors. As a result an iron-cored magnet has been chosen for construction. The excitation of the magnet is to be achieved by a d.c. motor-generator supplied with a fly-wheel. The requirements of the accelerating system, in which is included a radio frequency which changes by a ratio of about 1: 36 during the acceleration, are quite exacting. The methods by which it is hoped that these requirements will be met are outlined. The problems associated with injection and extraction of the particles receive some attention, and a schematic description of the proposed vacuum chamber is included. When protons of energies greater than 1010 eV. are to be obtained by a synchrotron, the cost of the device becomes overwhelming and some alternative method will have to be suggested. The application of the synchrotron being built at Birmingham to accelerating electrons, is limited to achieving electron energies of about 300- 00 MeV. because of radiation losses.