T-CUP: A NEW HIGH-PRESSURE APPARATUS FOR X-RAY STUDIES D. J. Weidner, Y. B. Wang, M. T. Vaughan, C. C. Koleda (CHiPR and USB), I. C. Getting (CHiPR and U Colorado at Boulder)

We have designed and tested a new apparatus for in-situ X-ray diffraction studies under high pressures and temperatures. The system is a 6-8 two stage system, designed for a 200 ton load, with the possibility of sintered diamond second stage anvils. The first stage is a steel cylinder split into six parts and fastened onto the upper and lower guide blocks, enclosing a cubic cavity (19.5 mm edge length and the [111] axis of the cube stays vertical). The hydraulic press used for SAM-85 DIA guideblocks is used to apply up to 200 ton load. The second stage is assembled outside the press and consists of eight WC cubes each with 10 mm edge lengths.

The cell assembly is an octahedron made of semi-sintered MgO or boron-epoxy. The incident x-ray beam passes through the gaps between WC cubes in the [110] direction of the eight-cube assembly and diffracts in one of the (100) planes, through gaps between the WC anvils, with a diffraction vector 35.3deg. from the vertical plane. A special holder is built for a solid-state detector for energy dispersive mode at several 2q angles up to 7.5deg.We compressed NaCl at room temperature to 160 ton force and generated 18+ GPa pressure with 2mm truncations. Deckers equation of state for NaCl was used to determined pressures in the cell assembly.