Abstract
The heat transfer from a metal to He II is determined by Kapitza conductance at the interface. Surface temperature estimation of the metal is used for the study of Kapitza conductance. The surface temperature is usually extrapolated from the temperature gradient in the metal. In the case of the metal with a coated layer, however, it is difficult to estimate the surface temperature. A similar case is applied for the superconductor of the helical coil of the large helical device (LHD). The copper surface is chemically treated by oxidation in order to improve the heat transfer characteristics in He I. It is planned that the helical coil will be cooled by He II in the phase II upgrade. The Kapitza conductance of the conductor has to be estimated for a stability analysis. Therefore, the heat transfer from the oxidized copper surface to the saturated He II has been measured using an oxygen-free copper cylinder. To investigate the thermal resistance in the oxidized layer, two coating surfaces are prepared: (a) coated with Stycast; (b) coated with Stycast on the oxidation layer. In this paper, the Kapitza conductance of the chemically oxidized copper surface is discussed.
Original language | English |
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Pages (from-to) | 367-371 |
Number of pages | 5 |
Journal | Cryogenics |
Volume | 41 |
Issue number | 5-6 |
DOIs | |
State | Published - 2001 |
Externally published | Yes |
Keywords
- Chemically oxidized copper
- Kapitza conductance
- Saturated He II