Accession Number : AD0696961
Title : DESIGN AND DEVELOPMENT OF AN ISOTOPIC ALTIMETER SETTING INDICATOR. VOLUME I.
Descriptive Note : Final rept.,
Corporate Author : PANAMETRICS INC WALTHAM MASS
Personal Author(s) : Sellers,B. ; Morel,P.
Report Date : JUN 1969
Pagination or Media Count : 90
Abstract : A need exists for an altimeter setting indicator system capable of operating up to ten digital displays and having an indicated error of plus or minus .005 inches of mercury. This report presents the results of a design and development program having the objective of determining the feasibility of using a radioisotopic source as the basic sensing element in such a system. The isotopic source selected for use in this system is the 5.5 MeV alpha emitter, americium-241, whose half life is 458 years. The basic parameter measured by this, and other isotopic emitters, is density. Thus, in order to make a measurement of pressure by direct sensing with such a source, it is necessary either to place the sensor in a controlled temperature enclosure which is connected to the point at which pressure is to be measured, or to monitor the temperature in the enclosure and utilize that information along with the density to calculate the pressure. The temperature must either be controlled or measured to an accuracy of about plus or minus .02C to meet the design objective on pressure. The approach utilized in the present system was that of a controlled enclosure. (Author)
Descriptors : (*ALTIMETERS, *GROUND POSITION INDICATORS), (*DETECTORS, *COUNT RATE METERS), RADIOACTIVE ISOTOPES, AMERICIUM, ALPHA PARTICLES, DENSIMETERS, DIGITAL COMPUTERS, SERVOMECHANISMS, DISCRIMINATORS, THERMAL STABILITY, SPECIAL FUNCTIONS(MATHEMATICAL), RELIABILITY, DESIGN, ACCURACY
Subject Categories : Flight Control and Instrumentation
Distribution Statement : APPROVED FOR PUBLIC RELEASE