Lloyd P. Smith

The Formation and Maintenance of Electron and Ion Beams

The radial potential distribution in an ionic beam of circular cross section is calculated and the maximum beam current which can be obtained in a beam of given radius and boundary conditions is computed. In the case of ions the maximum beam currents may be quite small. The ions in such beams have a considerable velocity distribution which in turn leads to a greater beam divergence than former calculations indicate. In Section 3 a method is worked out for holding the beam together during the initial accelerations. A disadvantage of cylindrical lenses is pointed out in this connection. The use of electrostatic lenses for holding together a beam composed of high energy particles is discussed in some detail. Calculations show the special arrangements of the lenses necessary for producing convergence of the beam. A few other arrangements to prevent divergence which were tried experimentally are described.

Heat Flow in an Infinite Solid Bounded Internally by a Cylinder

The problem of the flow of heat through a long tunnel wall in an infinite solid has been treated and the results for the rate of flow and total heat flow have been expressed in a convenient form for numerical computations. This general problem has become of interest in connection with the cooling of deep mines.

An Investigation of the Linear Accelerator

A treatment of the acceleration of particles by the linear resonance accelerator is given, including the calculation of the velocity distribution of particles emergent from the device and a method for improving the yield and the velocity distribution. Calculated curves showing these features are shown. The mass selection properties of the device are also considered. Focusing is considered briefly and a discussion of the characteristics of a quarter wave‐length line as applied to a resonance accelerator is included. The experimental features of a linear accelerator as built up are described. Probable particle energies to be expected from any future device of the kind are indicated.