Accession Number : ADA207562

Title :   An Improved Rubidium Consumption Model for Discharge Lamps Used in Rubidium Frequency Standards,

Corporate Author : AEROSPACE CORP EL SEGUNDO CA CHEMISTRY AND PHYSICS LAB

Personal Author(s) : Cook, Robert A ; Frueholz, Robert P

PDF Url : ADA207562

Report Date : 15 Apr 1989

Pagination or Media Count : 25

Abstract : The rubidium (Rb) discharge lamp is a critical component of the Rb gas cell atomic frequency standard. This frequency standard is flying on NAVSTAR/global positioning system (GPS) satellites and will find applications on future satellites. The reliability of the lamp is an issue of concern, and aging of the lamp has been modeled in a satisfactory way for reliability determinations (Ref. 1). As the lamp ages, it slowly loses its Rb Charge by diffusion of Rb into the lamp's glass walls. The model equation for Rb consumption C is C = A + B square root, where T is lamp operating time and B is an experimentally determined diffusion-related coefficient. A has been assumed to be loss resulting from a virtually instantaneous reactive process. In some of our data sets, consumption measurements indicate that the reactive cleanup is time dependent. We find this dependence well described by a term with two constants, A' and D, resulting from first-order reaction kinetics: A' 1 - exp(-DT)). Including this term improves the ability to predict long-term Rb consumption on the basis of a limited amount of experimental data. Consumption model, Discharge lamp, Frequency standard, Lamp reliability, Rubidium. (mjm)

Descriptors :   *DISCHARGE LAMPS, *STANDARDS, *RUBIDIUM, CLEANING, CONSTANTS, CONSUMPTION, DATA BASES, DIFFUSION, EQUATIONS, EXPERIMENTAL DATA, FREQUENCY, GLASS, LAMPS, MATHEMATICAL MODELS, MEASUREMENT, MODELS, REACTION KINETICS, REACTIVITIES, WALLS

Subject Categories : Inorganic Chemistry
      Physical Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE