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Nesting of Parts at Low Temperature

IP.com Disclosure Number: IPCOM000049984D
Original Publication Date: 1982-Aug-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Sokolowski, J: AUTHOR

Abstract

In Josephson device technology, it is often required that parts must be held with respect to one another at low temperatures and at room temperatures, without loss of axial alignment due to thermal cycling between room temperature and cryogenic temperatures. This fixture provides very accurate axial location and retention of two or more parts having different coefficients of expansion with temperature. There is no need for any allowance in nesting due to different thermal expansions of the materials. This allows the parts to be assembled at room temperature, without play, and then operated at cryogenic temperatures without a change in location.

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Nesting of Parts at Low Temperature

In Josephson device technology, it is often required that parts must be held with respect to one another at low temperatures and at room temperatures, without loss of axial alignment due to thermal cycling between room temperature and cryogenic temperatures. This fixture provides very accurate axial location and retention of two or more parts having different coefficients of expansion with temperature. There is no need for any allowance in nesting due to different thermal expansions of the materials. This allows the parts to be assembled at room temperature, without play, and then operated at cryogenic temperatures without a change in location.

Fig. 1A is a top view of the device, while Fig. 1B is a side view of a portion of the device. The device is comprised of a main body 10 onto which a wafer 12, such as a silicon wafer, is to be held and retained at low temperatures and at room temperature. A plurality of locating pins 14 are used to hold in line the wafer 12. This fixture holds wafers 12 without any movement of the wafer about the axis 16, either at room temperature or cryogenic temperatures. Pins 18 are used for mating different sections of the fixture.

The locating pins 14 are chosen to have a certain yield so that the wafer 12 can expand in all directions, causing the pins 14 to bend, as shown by the dashed line 20 in Fig. 1B. At room temperature, the locating pins 14 are straight, as indicated by the solid lines in Fi...