  SIKA, a high-flux cold-neutron triple-axis spectrometer at the OPAL reactor
at the Australian Nuclear Science and Technology Organization, is equipped with
a 13-blade analyser and position-sensitive detector. This multiplexing design
endows SIKA high flexibility to run in both traditional triple-axis and
multiplexing analyser modes. In this study, two different multiplexing modes on
SIKA are simulated using Monte-Carlo ray-tracing methods. The simulation
results demonstrate SIKA capabilities to work in these operational modes,
especially, the multi-Q const-Ef mode. This capability was demonstrated by
measuring the phonon dispersion of a Pb single-crystal sample with the multi-Q
const-Ef mode on SIKA. Compared to the traditional and multi-analyser
triple-axis spectrometers, multiplexing modes on SIKA combine the advantages of
the high data-acquisition efficiency and flexibility to focus on local areas of
interest in the (Q, w) space.
