From microns to millimeters: New Diamond Cells for Multi-Megabar pressures and for Neutron Diffraction

We developed new diamond cells for two extreme applications. One cell was designed to routinely study hydrogen above 2 Megabar (200 GPa) [2] by adopting the principle of deflecting plates reported earlier [1]. Neutron diffraction requires millimeter-sized samples even for the very high neutron fluxes available at the Oak ridge National Laboratory. We develop a new diamond cell capable of routinely reaching pressures of 80 GPa with culets of 1.5 mm. The diamonds were of only 4 mm diameter with conical design [3] using strongly supported seats made of polycrystalline diamond. We present new, high-quality data for D$_{2}$O showing signs of symmetrisation in ice [4]. Tests using very large CVD diamonds are in progress.\\[4pt] [1] Zha, C., Z. Liu, M. Ahart, R. Boehier, and R. Hemley (2013) \textit{Phys. Rev.Lett. in press}.\\[0pt] [2] Boehler, R. (2006), \textit{Rev of Sci Inst}, \textit{77}, 115103.\\[0pt] [3] Boehler, R., and K. De Hantsetters (2004) \textit{High Pressure Research}, \textit{24}, 391-396.\\[0pt] [4] M. Guthrie, R. Boehier, C. Tulk, A. M. dos Santos, K. Li, J.J. Molaison, and R. Hemley (2013), \textit{PNAS submitted}.