The invention provides an assembly having a cryostat and a flat coil layer of superconducting coils for use with a magnetic levitation and/or acceleration motor system of a lithographic apparatus. The cryostat has two insulation coverings. The coil layer is arranged between the two coverings. The coverings each have an inner plate configured to be cryocooled and an outer plate parallel to the inner plate, and an insulation system with a vacuum layer between the inner and outer plate. The insulation system of said covering has a layers of circular bodies, the central axes of these bodies extending perpendicular to the inner and outer plate, and is configured to provide a layer of point contacts between two layers of circular bodies or between a layer of circular bodies and the inner and/or outer plate.