Speaker
Description
Experiments to characterise the physical, chemical and electrical properties of superconducting materials and electronics often require measurements to be made at a number of fixed temperature values within a desired cryogenic temperature range. Temperature-controlled cold tables working in the range 4 to 300K are widely available, however the technology used in these systems is not directly transferrable to the sub-4K temperature
In this paper we describe the design and experimental demonstration of a tuneable heat link that is specifically designed for use at temperatures below 4K. Our tuneable heat link operates by active control of a convective flow of Helium 3 gas within a closed loop. The gas flow is initiated and controlled by electrically heating a small gas pod containing 3He adsorbed onto activated charcoal. The tuneable link is a compact, fully sealed unit (i.e. it requires no external gas connections) with no moving parts. It is designed to have an off-state conductance of approximately 35 microwatts with the ends tethered at 4K and 1K respectively. This means that it can be used with the 'cold end' thermally tethered to a sub-kelvin sorption module without unduly loading the module.
We will present data from experimental tests of the tuneable heat link to establish its off-state and on-state thermal conductance under a range of operating conditions. We will compare these data with the design models for the heat link and discuss practical use scenarios.
| Submitters Country | United Kingdom |
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