Boehler R, Molaison J J, Haberl B
Chemical and Engineering Materials Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA.
Instrument and Source Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA.
Rev Sci Instrum. 2017 Aug;88(8):083905. doi: 10.1063/1.4997265.
Traditionally, neutron diffraction at high pressure has been severely limited in pressure because low neutron flux required large sample volumes and therefore large volume presses. At the high-flux Spallation Neutron Source at the Oak Ridge National Laboratory, we have developed new, large-volume diamond anvil cells for neutron diffraction. The main features of these cells are multi-carat, single crystal chemical vapor deposition diamonds, very large diffraction apertures, and gas membranes to accommodate pressure stability, especially upon cooling. A new cell has been tested for diffraction up to 40 GPa with an unprecedented sample volume of ∼0.15 mm. High quality spectra were obtained in 1 h for crystalline Ni and in ∼8 h for disordered glassy carbon. These new techniques will open the way for routine megabar neutron diffraction experiments.
传统上，高压下的中子衍射在压力方面受到严重限制，因为低中子通量需要大的样品体积，进而需要大体积的压力机。在橡树岭国家实验室的高通量散裂中子源处，我们开发了用于中子衍射的新型大体积金刚石对顶砧池。这些池的主要特点是多克拉的单晶化学气相沉积金刚石、非常大的衍射孔径以及用于保持压力稳定性的气膜，尤其是在冷却时。一个新的池已被测试用于高达40吉帕的衍射，其样品体积达到前所未有的约0.15立方毫米。对于晶体镍，在1小时内获得了高质量光谱，对于无序玻璃态碳，在约8小时内获得了高质量光谱。这些新技术将为常规的兆巴中子衍射实验开辟道路。
