A cryostat includes a rotatable mounting arranged to rotate about a first rotational axis, the mounting extending substantially in a first plane, a sample plate arranged in use to support a sample, located on the rotatable mounting, and a heat sink located adjacent the side of the mounting distant from the sample plate. A thermal conductor extends between the sample plate and the heat sink. The conductor extends through an aperture in the rotatable mounting. A rotatable sample holder for a cryostat includes a sample plate having a first side arranged in use to support a sample, a drive gear arranged to rotate about a first rotational axis, and a driven gear arranged to rotate about a second rotational axis, engaged with the drive gear and coupled to the sample plate such that rotation of the drive gear causes the driven gear and sample holder to rotate. The first rotational axis does not intersect the second rotational axis.