Edgar Everhart

The Cockcroft‐Walton Voltage Multiplying Circuit

The conventional Cockcroft‐Walton voltage multiplying circuit is studied considering it as a transmission line. It is shown that, even when no direct current is drawn from the high voltage electrode, there is an important loss in output voltage caused by circulating currents in the stray capacitances. This loss of voltage is independent of the supply frequency. Formulas are developed for the voltage efficiency resulting from a given choice of capacitor size and number of stages.Two modifications of the Cockcroft‐Walton circuit which improve the voltage efficiency are suggested and analyzed. The first of these involves a loading coil at the high voltage end of the line. The second involves the addition of inductors in series with each of the capacitors of the circuit.

MEASUREMENTS OF THERMAL DISSOCIATION OF HYDROGEN, USING FAST PROTONS

Experiments involving study of the angular scattering of kiloelectron‐volt protons from atomic and molecular hydrogen targets have been used to measure directly the fraction of hydrogen gas dissociated in equilibrium with hot tungsten. The state of the hydrogen gas in a tungsten furnace is determined by analyzing the scattered incident particles which result from single collisions between the incoming protons and the hydrogen gas in the furnace. In particular, the number of H— ions among the scattered particles is a measure of the molecular hydrogen density, since H— ions cannot be created in single collisions between protons and hydrogen atoms. Under the present experimental conditions it was possible to achieve a fraction dissociated of over 87.5% at a furnace temperature of 2380°K and still higher fractions at higher temperatures. These measurements are made at hydrogen pressures of the order of 10—2 Torr.The practical conditions under which an atmosphere of highly dissociated hydrogen can be created a...

Making Corrector Plates by Schmidt’s Vacuum Method

The theory and procedure are given for figuring corrector plates for Schmidt cameras and related systems following Bernhard Schmidts classic method. The figure is achieved while the plate is deformed with a partial vacuum on one side. The method easily yields zone-free plates. A modification is described here wherein the correct profile is obtained without precise knowledge of the Youngs modulus or Poisson ratio of the particular glass disk in hand. The method is recommended for systems of f/2.5 or slower as there is danger of the plate breaking for faster systems.

Null Test for Wright Telescope Mirrors

The Wright telescope is a variation of the Schmidt design which uses a corrector plate at the focus and whose primary mirror is an oblate spheroid. A null test for the mirror is described, which is a modification of the Foucault test, and which makes use of the properties of a particular reference ellipse.