Advanced Sample Environments Cryogenic System for Faster Cooling of Samples in a Neutron Beam

The time for a sample to cool and then to change temperature in a traditional top loading cryostat and be significant. Time spent waiting for a temperature change is not productive data‐collection time, and it would therefore be beneficial to users in a neutron scattering facility, as well as to those in a University research laboratory, to reduce the time required to change the temperature of their samples. In particular, the problem is magnified when cooling high pressure cells, which are typically massive and slow to cool. The proposed project is to develop a new sample positioning rod with integrated liquid nitrogen heat exchanger and pre‐cooling line. The expectation is that liquid nitrogen can remove a substantial percentage of the heat from the cell quickly. When the cell is at nitrogen temperatures the nitrogen can be removed from the cooling line and the cryostat will take over to cool the cell to the required minimum temperature. In phase one we propose to design, build and test the sample positioner. In the design phase we will analyze the optimal heat exchanger design. We will test the positioner in an in‐house cryostat to determine the best operating procedure, then send it to Oak Ridge National Laboratory to have it tested with a high pressure cell. The new sample positioner design will be suitable for use in existing cryostats, and with an installed customer base of more than thirty top loading systems in neutron facilities alone, we anticipate interest from existing customers as well as new ones. This technology can also be extended to non‐neutron applications, e.g. cooling diamond anvil cells for optical applications. Beyond cooling pressure cells, this approach can be applied to cooling any heavy mass and will therefore be of interest to any potential cryogenic customer who desires to cool a heavy sample quickly. Top loading cryostats have the advantage of being able to cool samples evenly, even if they have poor thermal conductivity properties. Customers who may have chosen a different (faster) cooling method and found some way to work around the thermal gradient problems will have a new option for more uniform cooling in a shorter time.