A novel compact three-dimensional laser-sintered collimator for neutron scattering.

Improvements in the available flux at neutron sources are making it increasingly feasible to obtain refineable neutron diffraction data from samples smaller than 1 mm(3). The signal is typically too weak to introduce any further sample environment in the 30-50 mm diameter surrounding the sample (such as the walls of a pressure cell) due to the high ratio of background to sample signal, such that even longer count times fail to reveal reflections from the sample. Many neutron instruments incorporate collimators to reduce parasitic scattering from the instrument and from any surrounding material and larger pieces of sample environment, such as cryostats.

Strong isotope effects on melting dynamics and ice crystallisation processes in cryo vitrification solutions.

The nucleation and growth of crystalline ice during cooling, and further crystallization processes during re-warming are considered to be key processes determining the success of low temperature storage of biological objects, as used in medical, agricultural and nature conservation applications. To avoid these problems a method, termed vitrification, is being developed to inhibit ice formation by use of high concentration of cryoprotectants and ultra-rapid cooling, but this is only successful across a limited number of biological objects and in small volume applications. This study explores physical processes of ice crystal formation in a model cryoprotective solution used previously in trials on vitrification of complex biological systems, to improve our understanding of the process and identify limiting biophysical factors.

High-pressure cell for neutron diffraction with in situ pressure control at cryogenic temperatures.

Pressure generation at cryogenic temperatures presents a problem for a wide array of experimental techniques, particularly neutron studies due to the volume of sample required. We present a novel, compact pressure cell with a large sample volume in which load is generated by a bellow. Using a supply of helium gas up to a pressure of 350 bar, a load of up to 78 kN is generated with leak-free operation.

Large volume Bridgman seal cell for neutron scattering experiments at ultralow temperatures.

A pressure cell (maximum working pressure of 100 bars) has been developed for neutron scattering experiments at ultralow temperatures (T<100 mK) which makes use of a Bridgman seal design more usually seen in higher temperature experiments in the kilobar range. The large volume of the cell ( approximately 18 cm3) and its construction from a high-strength aluminum alloy make it suitable for inelastic neutron scattering experiments. The cell has been proof tested in operando in search for the supersolid state of helium-4.