Miscellaneous Cryogenic Accessories
Lake Shore Cryotronics
Lake Shore also supplies heat sink bobbins, a beryllium oxide heat sink chip, and a four-lead resistance sample holder. Cartridge heaters and vacuum feedthrough products are also available.
Heat Sink Bobbins
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 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 Chip
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 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 metallized 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.
Note: Due to metallization irregularities and surface dirt, it is not recommended that these chips isolate more than 100 V.
Superinsulation
- Aluminized plastic film
- Minimizes heat transfer by conduction
- Crinkled to provide stand-offs, eliminating the need for spacers
19-Pin Vacuum Feedthrough
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.
Note: The VFT19-FMC threads should be sealed with Teflon® tape or epoxy if a vacuum seal is important.
4-Lead Resistance Sample Holder
- 4 pre-tinned and drilled solder pads
- Plug-in convenience (4-pin plug)
- Mating socket included
Cartridge Heaters
Lake Shore cartridge heaters can be used with all of our temperature controllers. Heaters have wattage ratings in dead air. In cryogenic applications, these cartridge heaters can handle many times the rated value if properly hear sunk or in liquid.
| Part Number | Length | V | Ω | W |
|---|---|---|---|---|
| HTR-50 | 25.4 ± 2.4 mm (1 ± 0.094 in) | 50 | 50 | 50 |
| HTR-25-100 | 25.4 ± 2.4 mm (1 ± 0.094 in) | 50 | 25 | 100 |
- Precision-wound nickel-chromium resistance wire
- Efficient magnesium oxide insulation
- CSA component recognition
- 2 solid pins
- High-temperature rated INCOLOY®]® case
Electric Tape for Use at Cryogenic Temperatures
T1 roll = 12.7 mm × 65.8 m (0.5 in × 72 yd)
- Excellent tape for use at cryogenic temperatures—does not degrade with time like masking tape
- CHR Industries electrical tape
- Yellow polyester film
Ferrite Bead for High Frequency Filtering
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 like 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.
