High pressure sample environments of single crystal diffractometer SENJU

Munakata, Koji*; Nakao, Akiko*; Osakabe, Toyotaka  ; Ohara, Takashi   

SENJU is a single crystal time-of-flight neutron diffractometer installed at BL18 in the Materials and Life Science Experimental Facility (MLF) of J-PARC. It was designed for precise crystal and magnetic structure analyses under multiple extreme sample environments: it is possible to install a variety of properly designated sample environmental equipment into the vacuum chamber of SENJU. As well as the other external conditions, for example high magnetic field and low or high temperature, the high pressure is indispensable sample environment for physical or chemical studies such as pressure induced structural or magnetic transitions. In this presentation, we will show the recent status of high pressure sample environments in SENJU. Two types high pressure cell have been developed. One is self-clamped piston-cylinder cell, made of copper-beryllium alloy or Zr-based amorphous alloy, which can generate the pressure below about 2 GPa. The other is self-clamped opposed type hybrid anvil cell, consists of the pair of WC and single crystal sapphire anvils, which can reach higher pressure than piston-cylinder cell. Both cells are very compact and light. A GM-refrigerator cryostat with the rotation goniometer and the positioning mechanism for the high pressure cell is also developing.