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Browse Prior Art Database

Impurity Trap

IP.com Disclosure Number: IPCOM000098127D
Original Publication Date: 1960-Feb-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Lyons, VJ: AUTHOR

Abstract

In the course of purification of materials such as compound semiconductors or elements used in the synthesis of these compounds, it is often necessary to connect a tube containing such materials to a vacuum system for evacuation of the tube and filling of the tube with a high purity ambient gas. Since it is convenient to use stopcocks and ground glass joints in a vacuum system, there exists the possibility of contamination of the high purity material with components incorporated in stopcock grease and/or materials absorbed by the grease. Therefore, a low temperature trap of the design shown above is constructed in order to minimize such contamination. The trap is an integral part of the tube containing the sample and may be continually reused.

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Impurity Trap

In the course of purification of materials such as compound semiconductors or elements used in the synthesis of these compounds, it is often necessary to connect a tube containing such materials to a vacuum system for evacuation of the tube and filling of the tube with a high purity ambient gas. Since it is convenient to use stopcocks and ground glass joints in a vacuum system, there exists the possibility of contamination of the high purity material with components incorporated in stopcock grease and/or materials absorbed by the grease. Therefore, a low temperature trap of the design shown above is constructed in order to minimize such contamination. The trap is an integral part of the tube containing the sample and may be continually reused.

The sample which is to be heated is placed in a straight reaction tube. A baffle (tube sealed at both ends) is then placed in the tube. As the tube is evacuated, liquid nitrogen is placed in the vessel that surrounds the tube. Impurities condense on the walls of the section of the tube that is within the vessel. The baffle causes all gas to flow near the walls of the tube at that point where condensation should occur. The vessel is constructed with dual walls, the space between the walls being evacuated. All surfaces are constructed of quartz.

After each operation, the tube is fused closed between the sample and the vessel, and the portion of the tube containing the sample is removed. A new piece of tubing may...