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The difference in the ionization rates of holes and electrons in Si results in different properties of n+-p-p+ and p+-n-n+ TRAPATT diodes. An approximate analysis is presented which shows these differences and indicates superior performance in the n+-p-p+ structure.

R. J. C. Wood: Again we have an illustration of how, in different parts of the world, and at the same time, the same ideas arise simultaneously. The curves shown in this paper (Dwight) are — I think if you turn the diagram right over, or the wrong way up, according to who is talking about it, that it will be found to be very similar, if not identical with the curves to be shown in the paper by Mr. Holladay. That paper shows a diagram which represents the exact hyperbolic equations.

In this paper the overall-noise in a photodetection system, consisting of a Germanium avalanche-photodiode and a low-noise amplifier is determined. It turns out, that the main contributions to the overall-noise stem from the bulk- and guardring leakage currents and from the amplifier. The main parameter of interest for laser rangefinder applications is the noise-equivalent signal current, being equal to the peakvalue of the equivalent noise current at the amplifier input, divided by the avalanche multiplication factor. It turns out, that the optimum bias conditions for low-noise operation are rather temperature dependent. It is argued that current control is preferable to voltage control in order to stabilize against temperature variations. The optimum bias conditions and the corresponding minimum noise-equivalent signal currents are measured as functions of the ambient temperature. Besides the noise measurements the dynamic responses of some types of photodetectors are compared. It turns out, that various types of photo-responses are possible, dependent on the construction details of the device.

Interest in high-amplitude short-time voltage transients has increased with the introduction of solid-state equipment into the electrical system. The paper presents and discusses some of the causes of short-time voltage transients, the special instrumentation developed to measure these phenomena, and the results of preliminary measurements made aboard a number of naval ships.