Accession Number : AD0702755

Title :   TIME-RESOLVED MEASUREMENT OF DROPLET SIZE AND CONCENTRATION IN CLOUD CHAMBERS,

Corporate Author : BROWN UNIV PROVIDENCE R I DIV OF ENGINEERING

Personal Author(s) : Cole,John E. , III ; Dobbins,Richard A. ; Semerjian,Hratch

Report Date : MAR 1970

Pagination or Media Count : 28

Abstract : An optical method for measuring droplet size and concentration in a cloud chamber on a time-resolved basis is discussed. During the growth of the droplets optical transmission is continuously measured by high speed electronic equipment at two wavelengths. Interpretation of the resulting transmission versus time curves is made on the basis of Mie scattering theory. The appearance of oscillatory regions in the transmission curves is related to the primary oscillations of the scattering coefficient and indicates the presence of a monodisperse cloud. Two methods of data interpretation are discussed from which absolute values of droplet size and concentration are obtained. The technique is applicable to condensation studies conducted in Wilsen cloud chambers. It is suggested that apparatus of the type described is also suitable for the absolute calibration of condensation-nuclei counters of various types. (Author)

Descriptors :   (*CLOUD CHAMBERS, *PARTICLE SIZE), CALIBRATION, CONCENTRATION(CHEMISTRY), NUCLEATION, LIGHT TRANSMISSION, FOG

Subject Categories : Meteorology
      Nuclear Instrumentation

Distribution Statement : APPROVED FOR PUBLIC RELEASE