Time-of-flight powder diffraction text experiments at a pulsed neutron beam using the position-sensitive detector JULIOS

Performance tests for a 'JULIOS TOF diffractometer' were performed in a short-term experimental setup at a pulsed neutron beam at ISIS. JULIOS is a linear position-sensitive scintillation detector constructed for simultaneous recording of time-of-flight and angular dispersive spectra. Data sets were recorded in 256 channels each for time and position and transformed afterwards to constant d spacing patterns. Diffraction spectra were measured using standard polycrystalline samples like Si, Cu, Ni and quartz under various experimental conditions. Results are discussed with respect to resolution and intensity. Δd/d resolution in forward scattering geometry is analysed to 6.5x10-3. Mean background in the detector is 4 counts per h and channel. The peak to background ratio for the strongest quartz reflection is about 22 to 1. The experimental setup was used for structural investigations on HoFe4+yAl8-y and IrO2; least squares refinements based on d-dependent integrated intensities are reported. (orig.)