Accession Number : AD0487232

Title :   A STUDY OF THE STORAGE STABILITY OF THE BARIUM FLUORIDE FILM ELECTRIC HYGROMETER ELEMENT AND A REPORT OF THREE EXPERIMENTAL APPLICATIONS,

Corporate Author : NATIONAL BUREAU OF STANDARDS GAITHERSBURG MD

Personal Author(s) : Jones, Frank E.

Report Date : 20 APR 1966

Pagination or Media Count : 43

Abstract : A study of the aging properties of the barium fluoride film electric hygrometer element and of possible causes of the instability of the element, as exhibited by drift of calibration with time in storage, has been made. It was found that exposure of aged elements to glow discharge bombardment resulted in near recovery of the pre-storage calibration, indicating that the calibration drift was not irreversible and providing insight into the mechanism of aging. Based on the conjecture that aging was due, at least in part, to contamination of the barium fluoride film, production procedures were formulated which resulted in elements with significantly reduced drift. If an adjustment is made similar to the lock-in procedure in the operational use of radiosonde humidity elements, then the storage resistance values can be adjusted to correspons closely to the pre-storage calibration curves. Experimental evidence supports the hypothesis that contamination of the elements by diffusion pumping fluid in the production process was a source of the calibration drift. (Author)

Descriptors :   (*HYGROMETERS, AGING(MATERIALS)), PERFORMANCE(ENGINEERING), BARIUM COMPOUNDS, FLUORIDES, CALIBRATION, STORAGE, ELECTRON IRRADIATION, METEOROLOGICAL PHENOMENA, HUMIDITY, RECOVERY, CONTAMINATION, VACUUM APPARATUS, RADIOSONDES, HYSTERESIS, CLOUDS, LAKES, REFRACTIVE INDEX, FLIGHT TESTING.

Subject Categories : Meteorology

Distribution Statement : APPROVED FOR PUBLIC RELEASE