Browse Prior Art Database

Atomic Absorption Measuring Apparatus

IP.com Disclosure Number: IPCOM000075647D
Original Publication Date: 1971-Oct-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Cade, PE: AUTHOR

Abstract

This is apparatus for measuring the temperature and the density of an atomic vapor by analyzing the transmitted light of a light beam comprising two absorbable frequencies.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 63% of the total text.

Page 1 of 2

Atomic Absorption Measuring Apparatus

This is apparatus for measuring the temperature and the density of an atomic vapor by analyzing the transmitted light of a light beam comprising two absorbable frequencies.

A hollow-cathode light source emits a beam comprising wavelengths Lambda(a) and Lambda(b), e.g., 3962 Angstroms, respectively, through the vapor. e.g., Al atoms, in a sputtering apparatus. The transmitted light is split into 2 beams which go through filters for the wavelengths lambda(a),Lambda(b), respectively, to detectors with amplifiers, whose output is set equal to 1 in absence of vapor.

Vapor line 30 carries a signal Lambda(a) = (1-square rootT/T(E)) + square root T/T(E) - G(a)n square root T (with T the temperature and n the atomic density of the vapor atoms, T(E) the temperature of the emitting atoms in the hollow cathode and with 1 the path length of the light in the vapor, G(a) the Einstein "A" coefficient, M the mass of the atoms and k Boltzmann's constant). Line 31 has a similar signal for lambda(b).

In summing circuits 32 and 42 a signal equal to 1 for no absorption provided by circuit 33 is subtracted. The gain of following amplifiers 35 and 45 is set by a feedback signal on line 46. Their output signals are combined with the signals on lines 30 and 31 in summing circuits 34 and 44, respectively.

If the feedback signal is (1 - square root T/T(E)) / square root T/T the summing circuits supply exp- D n square rootT and exp- D(b)n square root T t...