Strong magnetic fields are achieved by using electromagnets, coils circulated by electric current. The Joule heating and power consumption of a metallic wire is huge so that the superconducting wire is usually preferred for the coil. The superconducting coil can be cooled down by a cryocooler with the advantage of autonomy (no need for replenishments). The same cooler can also be used in parallel for cooling down a sample holder for measurements of magnetic properties (Hall effect or Mossbauer spectroscopy, for instance), as long as the cooling power that is diverted from the coil does not put in risk the superconductor returning to its normal state. This is the main goal of this project. One of most popular forms of a heat switch is the gas gap one (GGHS). In a GGHS the thermal connection depends on the presence of a gas in the narrow gap space existent between two blocks. The amount of gas can be managed using the sorption properties of an activated charcoal and benefit from a compact, small and closed system. This way the actuation of the heat switch is made upon the heating/cooling of a cryopump. An original concept of heat switch is to be developed: the materials for both blocks and respective support are chosen according to their different thermal expansion coefficients, so they are assembled and sealed in physical contact, the designed gap opening only upon cooling down. The design and development of such switch namely for the sealing technique is to be carried on this project.
Partners: Fundação da Faculdade de Ciências e Tecnologia (FFCT/FCT/UNL); Active Space Technologies (AST); FCTUNL, University of Twente (TNW); Inter University Accelerator Centre (IUAC); Centro de Física e Investigação Tecnológica (CEFITEC/FCT/UNL); UNIDEMI
Funding organization: Science and Technology Foundation (PT)
Main achievements: A first prototype of the thermal switch was built in the FCT/UNL (CEFITEC, UNIDEMI) and is being tested in IUAC.