A novel diamond anvil cell for x-ray diffraction at cryogenic temperatures manufactured by 3D printing

Abstract

A new miniature high-pressure diamond anvil cell was designed and constructed using 3D micro laser sintering technology. This is the first application of the use of rapid prototyping technology to construct high-pressure apparatus. The cell is specifically designed for use as an X-ray diffraction cell that can be used with commercially available diffractometers and open-flow cryogenic equipment to collect data at low temperature and high pressure. The cell is constructed from stainless steel 316L and is about 9 mm in diameter and 7 mm in height, giving it both small dimensions and low thermal mass, and it will fit into the cooling envelope of a standard CryostreamTM cooling system. The cell is clamped using a customized miniature buttress thread of diameter 7 mm and pitch of 0.5 mm enabled by 3D micro laser sintering technology; such dimensions are not attainable using conventional machining. The buttress thread was used as it has favourable uniaxial load properties allowing for higher pressure and better anvil alignment. The clamp can support the load of at least 1.5 kN according to finite element analysis (FEA) simulations. FEA simulations were also used to compare the performance of the standard thread and the buttress thread, and demonstrate that stress is distributed more uniformly in the latter. Rapid prototyping of the pressure cell by the laser sintering resulted in a substantially higher tensile yield strength of the 316L stainless steel (675 MPa compared to 220 MPa for the wrought type of the same material), which increased the upper pressure limit of the cell. The cell is capable of reaching pressures of up to 15 GPa with 600 μm diameter culets of diamond anvils. Sample temperature and pressure changes on cooling were assessed using X-ray diffraction on samples of NaCl and HMT-d12.

Single-crystal neutron diffraction in diamond anvil cells with hot neutrons

“…Note that the maximum pressure that can effectively be reached in the sample chamber is much higher than this average pressure. According to Sadkov & Solodukhina (1993) and Jin et al (2017), the actual pressure limit could be three times as high as that determined from the finite element analysis, providing the diamond anvils withstand these conditions. Thus, for a culet diameter of 1 mm, a critical (FEA) pressure limit for the cell of about 4 GPa (Fig.…”

Pressure effect investigations on spin-crossover coordination compounds

“…The vital importance of structural studies in rationalising SCO behaviour is clear, however, the difficulties associated with mounting a traditional DAC inside a cryostat on a goniometer have sofar limited such studies to central facilities [79]. Recent developments in the production of miniature DACs that can be mounted on an in-house diffractometer and are small enough to be cooled by standard open-flow cryo-cooling devices present exciting opportunities, [122] and it is hoped that such devices will accelerate research in this area.…”

Use of a miniature diamond-anvil cell in a joint X-ray and neutron high-pressure study on copper sulfate pentahydrate

“…The DAC used in this work can be cooled in a closed-cycle cryostat, so that joint variable-temperature X-ray and neutron studies should also be possible down to temperatures only a few degrees above absolute zero. Use of a still-furtherminiaturized cell, such as that described by Jin et al (2017), would even permit cooling with open-flow cryostats such as the Oxford Cryostream. Although the focus of this study has been on diffraction, the cell is also suitable for Raman, UVvisible and other spectroscopic measurements; the CuBe alloy used to construct the cell body would potentially enable simultaneous use of a magnetic field during diffraction measurements.…”

“…Having ready access to an X-ray diffractometer adjacent to the neutron diffractometer for rapid identification of the sample reflections, sample-quality checks and unit-cell determination would optimize the use of neutron beam time. Use of a smaller DAC such as that described by Jin et al (2017), which has a pressure limit of 15 GPa but is substantially smaller with lower beam attenuation than the one used here, would also enable the measurements to be conducted more quickly.…”