Superconducting Technology Assessment - nitrd

6.3 ENCLOSURES AND SHIELDS
TABLE 6-3. 3D PACKAGING DEVELOPMENT COSTS ($M)
Year 2006 2007 2008 2009 2010 Total
Fabrication Equipment ($M) (covered in MCM Foundry investment)
3D Development Total 1.3 2.0 2.0 0 0 5.3
Total Investment 1.3 2.0 2.0 0 0 5.3
Enclosures and shields (illustrated in Figure 6-5) are required to operate SCE at cold temperatures, under vacuum
or without magnetic interference, undue radiative heat transfer or vibration. The vacuum dewar is an integral part
of the cryocooler operation and should be designed concurrently. A hard vacuum is needed to minimize convective
heat transfer from the cold to warmer parts. Vibration of the system can translate into parasitic magnetic currents
that may disrupt the operation of SCE circuits.
Figure 6-5. The construction details of a typical enclosure designed for operation at 4 K4 . The overall enclosure is shown at left. The details of
the housing for SCE circuits are shown in the cut-away at right.
6.3.1 ENCLOSURES AND SHIELDS – STATUS
Technical challenges for enclosures and shields include how to penetrate the vacuum walls and shields with large
numbers of cables, both for high DC current power supplies and very-high-frequency (50-100 GHz) digital signals,
while minimizing heat flow into the low temperature environment.
4 “Integration of Cryo-cooled Superconducting Analog-to-Digital Converter” D. Gupta et al, ASC 03’
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