Joseph G. Hirschberg

A Multichannel Fabry-Perot Interferometer

The advantages of the Fabry-Perot interferometer in resolution and luminosity are combined with those of a multichannel spectrometer for the investigation of spectral line shapes and shifts as a rapid function of time. The heart of the instrument is an array of concentric annular mirrors which perform the wavenumber separation, sending the light from each channel into a separate photomultiplier.

Doppler Temperatures in the C Stellarator

A convenient method for the accurate measurement of Doppler temperatures as a function of time has been developed and applied to the C Stellarator. General agreement between Doppler and other temperature measures has been found when the plasma is quiescent. Late in the period of plasma containment however, the ion‐Doppler temperatures begin to fall appreciably below the electron temperature. This is shown to be explainable in terms of an influx of cold gas which tends to overcome the heating by the electrons.

Simple Duochromator for the Measurement of Small Displacements of a Spectral Line

Doubly refracting prisms are used to convert an ordinary Ebert monochromator into a duochromator adapted to measuring small wavelength shifts in a spectral line. The instrument has the advantages of simplicity, good time resolution, high luminosity, and geometrically identical channels. An example of its use is given.

Deviations from Kinetic Equilibrium in a Stellarator Plasma

The increase in Doppler temperature with charge number, found in stellarators, has been remeasured with improved precision for observation parallel to the lines of force. No dependence on position was found, and the results are ascribed tentatively to positive‐ion waves parallel to the magnetic field.

Soft X-Ray Laser Microscopy

Microscopes based on soft X-ray lasers possess unique advantages in bridging the gap between high resolution electron microscopy of dehydrated, stained cells and light microscopy at comparatively low resolution of unaltered live cells. The high brightness and short pulse duration of soft X-ray lasers make them ideal for flash imaging of live specimens.

Temperatures of Neutral Atoms in C‐Stellarator Discharges and Charged‐Particle Temperatures of the Afterglows

The kinetic temperatures of neutral helium and hydrogen atoms in ohmically heated discharges of the C stellarator were determined from measurements of spectral profiles of the λ4921, 21P−41D line of HeI and the Hβ line of hydrogen. The time resolution of the measurements was about 250 μsec, or about 110 of the duration of the discharge. It was found that the neutral atoms were at all times at a temperature much higher than the walls of the discharge vessel, with highest temperatures in the neighborhood of 2 eV. The results are interpreted in terms of energy transfer between electrons and ions through Coulomb collisions, between ions and neutral atoms through resonant charge exchange, and between neutral atoms and the walls through semielastic collisions. In addition, the temperature of the recombining ions in the afterglow of the discharges was determined by the same method, and found to be in good agreement with simultaneously measured electron temperatures.

Composition Product Simulator

A simple optical analog device has been constructed to solve the convolution integral equation. It has been applied to the problem of measuring the shape and half-intensity breadth of spectral lines when using instruments with nonnegligible instrumental broadening.