TIME OF FLIGHT NEUTRON DIFFRACTOMETER FOR INVESTIGATION OF MICROSAMPLES UNDER HIGH EXTERNAL PRESSURE.

V.L.Aksenov¹, A.M.Balagurov¹, V.P.Glazkov², D.P.Kozlenko¹, B.N.Savenko¹, D.V.Sheptyakov¹, V.A.Somenkov<sup>2

1</sup> JINR, Frank Laboratory of Neutron Physics, 141980 Dubna, Russia.
² Russian Scientific center "Kurchatov Institute", 123182, Moscow, Russia.

A new high pressure neutron diffractometer DN-12, installed at the IBR-2 pulsed neutron source is described. The device includes a chopper, collimation system, two ring shaped detectors and anvil-based pressure cells of different types. Neutron diffraction studies of ammonium halides ND₄Br, ND₄Cl and high -T_c superconductors Hg-1212 and Hg-1201 have been performed at pressures up to 5 GPa with the use of sapphire anvils. After first successful experiments, the development of the DN-12 was made during the last year. The straight vacuum neutron guide has been substituted by supermirror curved neutron guide and the parameters of the diffractometer were considerably improved. First results and further perspectives for high pressure neutron diffraction studies with the DN-12 diffractometer are discussed.

The work was supported by Russian Foundation of Basic Research, grants N97-02-16622 and N97-02-17587.