CHAPTER 4: WIRING AND CONNECTIONS

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FIG. 4.1
Thermal resistivity of common wire materials

FIG. 4.2
Cross-sectional view of a heat-sink scheme for larger probes
(<= 2 cm diameter)

FIG. 4.3
Cross-sectional view of a heat-sink scheme for smaller probes
(<= 1.5 cm diameter)

FIG. 4.4
Illustration of noninductive winding scheme for further minimizing induced voltages in instrumentation leads when making measurements in high magnetic fields

FIG. 4.5
Beryllium-oxide heat-sink chips for thermally anchoring instrumentation leads

FIG. 4.6
Technique for attaching fine electrical leads to small samples, especially when using weak silver paint to contact the sample

FIG. 4.7
Technique for attaching a bare copper wire to a copper block, which minimizes thermoelectric voltages

FIG. 4.8
Several schemes for making low-thermoelectric-voltage connections between the test apparatus leads and the leads from a sensitive voltmeter

FIG. 4.9
Connector box Ð nonvacuum tight

FIG. 4.10
Conventional multipin D-connector adapted for a vacuum tight seal

FIG. 4.11
Connector chamber Ð vacuum tight

FIG. 4.12
Vacuum-tight aluminum connector box with removable plates for mounting commercial vacuum-tight multiple-pin connectors

FIG. 4.13
Removable vacuum lead-through for continuous leads to minimize thermoelectric voltages

FIG. 4.14
Cryogenic vacuum-tight electrical lead-through

FIG. 4.15
Superconducting rf transmission lines

FIG. 4.16a
Optimum wire diameter for a single copper wire conducting current I from a region of the cryostat at temperature Tupper to a temperature Tlower

FIG. 4.16b
Minimum heat input for a single copper wire conducting current I from a region of the cryostat at temperature Tupper to a temperature Tlower

FIG. 4.17
Illustration of a 150 A vapor-cooled high-current lead

FIG. 4.18
Helium-gas trap for venting a dewar without allowing air to condense and freeze in the dewar or vapor-cooled leads

FIG. 4.19
Critical-current density as a function of magnetic field at various temperatures for a Bi2Sr2Ca2Cu3O10 current lead

FIG. 4.20
Flexible high-current lead

References
Listing of all References for Chapter 4 Figures