Salle des séminaires – Bâtiment A
Titre : Development of continuous sub-millikelvin refrigerator, and isotopic purification of helium-3
Résumé : The duration of experiments requiring ultra-cold temperatures below 1 millikelvin is currently limited to a few tens of hours because of the need to periodically recycle Nuclear Demagnetization Refrigerators (NDR). I will present our progress towards a two-stage continuously operating NDR, designed to be mounted on a cryogen-free dilution refrigerator. Overall design criteria and selected solutions will be presented. Development and testing of key components, including a recently demonstrated ultra-high conductance superconducting heat-switch will be described.
I will also briefly present the results of additional unrelated work concerning the isotopic purification of 3He through fractional adsorption on activated charcoal.