Fast Cooling Technology for Sample Stick in Top Loading Cryostats

Abstract Cryostats are essentially important sample environments for low-temperature neutron scattering experiments. They are primarily used to investigate materials of interest, i.e., samples of crystalline solids or powders, at temperatures below 100K. Dry cryostats, where the samples are cooled by helium exchange gas, are favored due to their simple operation, low maintenance, and, most importantly, moderate usage of progressively more expensive helium. However, samples in dry cryostats usually take almost two hours to cool from room temperature to ∼80 K, causing time-consuming changeover delays. Since neutron scattering experiments are usually conducted under strict time restraints at large-scale user facilities, maximizing instrument time utilization is of great significance. A novel sample stick with an embedded liquid nitrogen transport line is presented and shown to achieve improved cooling performance by involving the boiling of liquid nitrogen. The preliminary experiments demonstrate a cooling time of 2 min, compared to ∼2 hr for a typical dry cryostat.