  We report on studies of non-toxic scintillating liquid useful for large
surface detectors. Arrays of liquid scintillators offer a rather simple tool
for detecting charged particles traversing a surface and tracking their path
through a defined volume. Insertion of wavelength shifting fibres along the
liquid scintillating containers significantly improves the light collection at
the two ends of the scintillators. We have demonstrated that we can achieve
timing resolution of O(1 ns) allowing good spatial resolution. Liquid
scintillators with fibres read by Photo-multipliers or SiPMs provide an
inexpensive alternative technology which suits well the requirement of the
MATHUSLA experiment tracking system.
