High-pressure neutron diffraction techniques based on Paris-Edingburgh press

Abstract

Since the 1990s, with the benefit of available large-volumed samples, wide detector windows, and portability, Paris-Edinburgh press has been widely used in neutron facilities to study the structures and physical properties of condensed matter under high-pressure extreme conditions. In the present study, We perform high-pressure neutron diffraction experiments in neutron source of China using the Paris-Edinburgh press. The experiments are carried out on a high-pressure neutron diffraction spectrometer (Fenghuang) at China Mianyang Research Reactor (CMRR). Fenghuang is a high-intensity and moderate-resolution diffractometer which has been upgraded from a neutron powder diffractometer and can be used under ambient and extreme conditions. A single cylinder pump with a max load of 200 MPa provides a loading pressure for Paris-Edinburgh press, and a precise mobile platform is used to hang and to locate the Paris-Edinburgh press. Using the tungsten-carbide (WC) toroidal anvils with TiZr gasket, we obtain the neutron diffraction spectra of Fe samples at different pressures successfully. We also obtain the neutron diffraction spectra respectively at pressures of 9.7 GPa and 10.7 GPa by using a WC single-toroidal anvil and a WC double-toroidal anvil under load 100 MPa. The TiZr gasket blows out before the load reaches 100 MPa in the WC single-toroidal anvil assembly, while it remains good in the WC double-toroidal anvil assembly under the same load. The WC single-toroidal anvil assembly becomes unstable under load about 80 MPa, and the WC double-toroidal anvil assembly is still stable under load 100 MPa. Thus, the stability of the double-toroidal anvil assembly is much higher than that of the single-toroidal anvil assembly. It is found that the thickness of the gasket edge is very important for the stability of the assembly during loading. The thicker the edge of the gasket, the more stable the assembly is. The main reason is that the groove of the double concave anvil can enhance the lateral support ability of the gasket, thereby making the double concave surface assembly more stable than the single concave surface assembly.

Influence of the Ammonia Concentration in Chemical Bath Deposition and Selenourea Concentration in Hydrothermal Process on the Properties of CdS and Sb2S3−ySey Thin Films and the Photovoltaic Performance of the Corresponding Solar Cells

“…Compared with Figure 2a–c and Figure 1a–c, it can be seen that the CdS nanoparticles in the thin films were melted together, which was in accordance with the previous report. [ 14 ] The R q of CdS thin films on the FTO increased to 16.5 nm of 0.72 m , 17.5 nm of 0.59 m , and 18.9 nm of 0.46 m , also increasing with the decrease of ammonia concentration (the corresponding AFM images are shown in Figure S3, Supporting Information). The energy‐dispersive spectrometer (EDS) analysis revealed that the atomic ratio of Cl:Cd in the CdS thin films was 0.10:1 of 0.72 m , 0.12:1 of 0.59 m , and 0.15:1 of 0.46 m from Figure S4, Supporting Information (the X‐ray diffraction [XRD] and UV–vis–NIR of the CdS thin films are also provided in Figure S5 and S6, Supporting Information).…”

“…The result was because CdCl 2 can serve as the assisted melting reagent. [ 14 ] Therefore, the compact and full‐coverage CdS thin films with thickness of 50 ± 6 nm can be obtained using the low concentration of ammonia (0.59 m ).…”

The design of 2/8-type high-pressure cell applied to in situ neutron diffraction*

“…[31] The loading force is generated by the 2000 kN Paris-Edinburgh press. [32] An iron cylinder (99.99%, Alfa Aesar, US) with a size of Φ2 × 2 mm was used as a sample. The sample pressure was continuously monitored in situ by using the equation of state (EOS) of crystalline Fe.…”