Development of Opposed-Type Anvils with Wide-Angle Aperture and Investigation of Pressure-Induced Phase Transition of Ca(OD)₂

Abstract

Newly designed opposed-type anvil assemblies were developed for acquiring high signal intensity of neutron diffraction data and ruby fluorescence spectra. Ni-binded WC anvils with a wide aperture angle, which were combined with a hybrid gasket made of TiZr and Al-alloy, achieved nearly ～15 GPa at room temperature. The neutron diffraction intensity was 2.5-3.0 times greater than that using the conventional toroidal anvil assemblies. The performance test of these new anvil assemblies confirms that sufficient quality diffraction data can be obtained. Using these assemblies, high-pressure behavior of hydrogen bond in Ca(OD)₂ was investigated at PLANET beamline, J-PARC.