An inventive embodiment comprises a thermalization arrangement at cryogenic temperatures. The arrangement comprises a dielectric substrate (2) layer on which substrate a device/s or component/s (1) are positionable. A heat sink component (4) is attached on another side of the substrate. The arrangement further comprises a conductive layer (5) between the substrate layer (2) and the heat sink component (4). A joint between the substrate layer (2) and the conductive layer (5) has minimal thermal boundary resistance. Another joint between the conductive layer (5) and the cooling heat sink layer (4) is electrically conductive.