Browse Prior Art Database

Process Control For Producing Particles in a Vacuum

IP.com Disclosure Number: IPCOM000048626D
Original Publication Date: 1982-Feb-01
Included in the Prior Art Database: 2005-Feb-08
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Brunsch, A: AUTHOR [+3]

Abstract

The size and density of particles 7 in the inert gas of vacuum chamber are measured and controlled by means of detector 5. The intensity and state of polarization of light 6, reflected according to the Tyndell effect, are measured perpendicularly to a strong light beam 1 incident on the cluster of particles 7. In comparator 8, the measured values are compared with desired values. By means of inert gas inlet valve 14 and HF source 9, respectively, the particle size and density or rate are adjusted.

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Process Control For Producing Particles in a Vacuum

The size and density of particles 7 in the inert gas of vacuum chamber are measured and controlled by means of detector 5. The intensity and state of polarization of light 6, reflected according to the Tyndell effect, are measured perpendicularly to a strong light beam 1 incident on the cluster of particles 7. In comparator 8, the measured values are compared with desired values. By means of inert gas inlet valve 14 and HF source 9, respectively, the particle size and density or rate are adjusted.

The figure is a schematic representation of the design of the set-up. Light beam 1 of an intensive light source 2, for example, a carbon arc, is led through vacuum chamber 4 underneath particle collector 3. Detector 5, arranged perpendicularly to light beam 1, determines the intensity and state of polarization of incident light 6. If light beam 1 impinges upon particles 7, it is scattered perpendicularly to its direction of incidence and polarized, reaching detector 5 in accordance with the Tyndell effect. Particle size and density in the gas are deduced from the intensity and state of polarization of light 6 by means of detector 5.

In comparator 8, the values thus obtained are compared with corresponding desired values. If the intensity of the light differs from the desired value of the particle size, the power of HF source 9 is adjusted by means of density or rate control 10, so that by appropriately heating the HF c...