Miscellaneous cryogenic accessories

Heat sink bobbins for cryostat lead wires are gold-plated OFHC or ETP copper for removing heat flowing down sensor leads. The small bobbin holds 4 to 8 phosphor bronze or manganin wires, and the large bobbin holds up to 40, depending on the wire gauge and number of wraps. 4 or 5 wraps are usually sufficient, using VGE-7031 varnish or Stycast® epoxy for potting the wires. Do not use copper or other high-conductivity wires.

Beryllium oxide heat sink chips can be used to heat sink electrical leads or samples at low temperature with good electrical isolation. They can also be used as a buffer layer to take up expansion mismatch between an object with a large expansion coefficient (e.g., copper, epoxy) and an object with a low expansion coefficient (e.g., a DT-670-SD diode sensor). One side is fully metalized with molybdenum/manganese, followed by nickel and gold. It is easily soldered with In/Ag solders. Sn/Pb solders can pull up metallization under some circumstances. The other side has two 1.27 mm (0.05 in) by 4.06 mm (0.16 in) electrically isolated solder pads. The thermal conductivity is several times that of copper in the liquid nitrogen region but about 1000 times lower at liquid helium temperature. The magnetic susceptibility is about that of nonmagnetic stainless steel.

This hermetically sealed glass-to-metal electronic connector is designed to meet the dimensional requirements of MIL-C-26482 and is furnished with a silicone o-ring to seal against the mating connector plug shell. It is commonly used to pass electric signals into a vacuum chamber from the outside.

1 roll = 12.7 mm × 65.8 m (0.5 in × 72 yd)

RF pickup can affect an experiment by upsetting the instrument reading, by being rectified by a diode thermometer to appear as an offset, or by transmitting through the system wiring to pollute the experimental environment. A ferrite bead will reduce the effect of RF pickup on instrument leads by acting as a high impedance (resistance) to high-frequency noise. DC and slow-moving signals are not affected. The bead can be clamped around existing wiring for ease of installation.