A portable MRI or NMR imaging system comprising a cryogen vessel housing cooled equipment, said system being housed within a transportable container, said container being divided into at least three sections. A first section provides accommodation for an operator and access to equipment as required to operate the cooled equipment. A second section houses the cryogen vessel. A third section houses auxiliary equipment required for operation of the cooled equipment but which is not required to be accessed by the operator to operate the equipment.Also provided is a cryostat comprising an outer vacuum container, itself housing a cryogen vessel for containing cooled equipment, wherein space between the cryogen vessel and the outer vacuum container is evacuated. The outer vacuum container is in the form of at least a section of a standard shipping container.