Liquid Helium Cryostat for Mössbauer Scattering Experiments

A simply constructed cryostat designed for Mössbauer γ-ray scattering experiments is described. The sample volume is part of the transfer line from a liquid helium reservoir to a mechanical pump; the sample is thus cooled by helium flow. The helium vapor exiting from the sample volume cools the transfer line and radiation shield. The temperature of the sample is controlled by the helium flow rate determined by a needle valve at the pump. The operating range is from 9 to ∼300°K. The liquid helium consumption in liters/h is 0.3 at 10°K, 0.2 at 16°K, and 0.1 at 34°K. Possible modifications to improve the operating characteristics are discussed.