KENS report-12

This report presents a summary of research activities performed at KENS facility during the period between Jan, 1997 to Mar, 1999. High Energy Accelerator Research Organization (KEK) was established by unifying National Laboratory for High Energy Physics and two Institutes of University of Tokyo, Institute for Nuclear Study and Meson Science Laboratory in order to realize Japan Hadron Facility (JHF) project. KENS facility was included in Institute of Materials Structure Science in the new organization. In March 1999, KEK and Japan Atomic Energy Research Institute (JAERI) concluded an agreement that we promote a joint project of JHF and Neutron Science Project of JAERI for construction of the next generation neutron facility. Two spectrometers using cold neutrons, a polarized neutron reflectometer (TOP) and a small-and wide-angle neutron diffractometer (SWAN), have been improved after the reconfiguration in a new cold-neutron guide hall, and their user program has started. A single crystal diffractometer (FOX) newly installed a multi-detector system, which allows observation of a large area of reciprocal space in a single measurement. Crystal structure of several battery materials were determined with powder diffractometers (Vega and Sirius) and intensive studies have been also performed on spin dynamics in a one-dimensional Heisenberg antiferromagnetic system using a chopper spectrometer (INC) of KENS and instruments of ISIS facility under the UK-Japan collaboration. (M.N.)