323 / 2019-02-25 21:25:34

High pressure neutron diffraction techniques and its applications at CMRR

High pressure neutron diffraction,Paris-Edinburgh press,High pressure solubility

全体主题 > High Pressure Physics and Materials Science

The China Mianyang Research Reactor (CMRR) with the power of 20 MW is located in Mianyang city, Sichuan province. Eight neuron scattering instruments were installed in the thermal and cold neutron halls of CMRR, and open to users from 2014. Fenghuang, a high-intensity and moderate-resolution diffractometer has been upgraded from a neutron powder diffractometer, can be used for research at ambient and extreme conditions. A novel assembly of a horizontally focusing neutron guide and a horizontally adjustable slit between sections of the guide significantly increased intensity to 2.84 × 106 ns-1cm-2 at the sample position, and allowed to conveniently adjust the resolution of the diffractometer [1].
Based on Fenghuang diffractometer, the high pressure techniques have been developed and various sample environment devices have been established [2]. High pressure devices include 150 ton two-anvil press which equipped with sample heating system, high precision sample orientation system and 200 ton Paris-Edinburgh press (VX4). At present, the maximum high pressure of in-situ neutron diffraction has been up to 30 GPa with the sample size of millimeter scale [3]. A series of applications were also performed recently, such as development a neutron diffraction method for making high-precision in situ measurements of crystal solubility versus pressures over a wide range of pressures [4], and determined the crystal structures of the C6H6-C6F6 cocrystal phases under high pressure and found it finally polymerized into H-F graphane with layered structure [5].