Two neutron diffraction facilities in Kyoto University Reactor (KUR)

The control systems for KUR neutron diffraction facilities provided with an 8 bit microcomputer PDC-8 are introduced. The KUR has a four-axis type neutron diffraction facility mainly applied to crystal structure analysis and a three-axis type neutron diffraction facility capable of analyzing scattered neutron energy and also aiming at magnetic structure analysis. In the four-axis type facility, the neutron intensity scattered from each crystal face is automatically measured by rotating each of three-dimensional sample crystal faces in a plane, and in the three-axis type facility, measurement is automatically made on a crystal face desired to be measured, which is placed in a plane in advance. The computer system consists of counting systems, a goniometer and a typewriter centering around the PDC-8. The PDC-8 is provided with an operating panel, interface cards and a power supply, and operated using BASIC. The operation of the system is executed by the interactive form with TTY, the selection of measuring modes and the data inputting proceed under the CPU commands, and the program selection is performed by inputting control codes at the keyboard. The present microcomputer capacity has a sufficient speed to control, though processing speed is slow. However, it is disadvantageous for input parameters requiring complicated calculation. This calculation is executed using a FACOM U-200 computer, and the PDC-8 is controlled by inputting the results with paper tapes. (Wakatsuki, Y.)