QUARTERLY PROGRESS REPORT NO. 49 FOR PERIOD ENDING APRIL 15, 1958
Measurement of diode characteristics of junctions in germanium at very low voltages has been carried out. The effect of a magnetic field and of a unidirectional heating current on thermionic emission from molybdenum has been measured. The frequency response of the Shelton electrometer has been extended by mechanical redesign of the input circuit. An internal disappearing-filament pyrometer was designed. An experiment designed to measure the cyclotron resonance of molecular and atomic ions in a hydrogen plasma is in progress. A system using a twin-T null network for measurement of the ionized plasma properties, the normalized change in measurement coil inductance and the normalized change in resistance, has bcen developed. The collision cross section and the energy loss of slow electrons in hydrogen were measured. Microwave measurements of electron temperatures in the presence of a static magnetic field were investigated. An optical method has been devised for measuring the relative change of electron energy or temperature of a changing plasma. The five elastic constants of zinc have been measured from 4.2 to 77.6 deg K by an ultrasonic pulse technique. One measurement on a ruby single crystal has yielded a spin- lattice relaxation time of 0.037 plus or minus 0.005 sec. A potassium cobalticyanide crystal was used to give sufficient population inversion of a two- level system by the 160 deg pulse technique to exceed unity gain, and on one occasion sufficient gain was obtained to produce oscillation. The paramagnetic properties of chromium ions present as an impurity in Al/sub 2/O/sub 3/ were examined at microwave frequencies. A series of measurements of thc spin-lattice relaxation time of F/sup 19/ nuclei in lithium fluoride crystals was completed. The effect of temperature broadening and self-reversal of the hyperfine structure of the Hg 2537 resonance line was studied. An FM receiver that incorporates a dynamic trap for capturing the weaker of two cochannel signals has been built and tested. The first two of twelve lectures by Norbert Wiener on nonlinear problems in random theory are presented. In statistical communication theory the invariance property of correlation functions under nonlinear transformations, statistical errors in measurement on amplitude-distorted Gaussian signals, and uniqueness of first-order output distributions of linear systems by the moment method have been investigated. A dynamic analog speech synthesizer and a terminal analog nasal consonant synthesizer are described. Work on mechanical translation, communications biophysics, neurophysiology, and network synthesis is reported. The design problems of a Stark cell for microwave spectroscopy are described. (For preceding period see NP-6620.) (W.D.M.)
- Research Organization:
- Massachusetts Inst. of Tech., Cambridge. Research Lab. of Electronics
- DOE Contract Number:
- DA36-039-SC-64637
- NSA Number:
- NSA-12-011488
- OSTI ID:
- 4315754
- Report Number(s):
- NP-6775; Project 3-99-00-100
- Resource Relation:
- Other Information: Project 3-99-00-100. Orig. Receipt Date: 31-DEC-58
- Country of Publication:
- United States
- Language:
- English
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