A device for isolating a heat sensitive component includes a heat sink positioned adjacent to the heat sensitive component. The heat sink has a stepped thermal response to an applied heat. The heat sink may include two or more thermally decoupled masses. Thermal decoupling may be achieved by positioning a nanoporous material positioned between the two masses. The heat sensitive component and the heat sink may be positioned inside a container such as a Dewar-like flask and connected to the container with a connector. The connector may function as a thermal isolator that impedes the flow of heat into the interior of the container. In one embodiment, the connector includes at least one bridge portion having a reduced cross-sectional area and/or a longitudinally elongated opening to impede heat flow. Nanoporous material may be positioned in the container at locations that assist in thermally isolating the heat sink and heat sensitive components.