  A simple device for determining the azimuthal location of a source of gamma
radiation, using ideas from astrophysical gamma-ray burst detection, is
described. A compact and robust detector built from eight identical modules,
each comprising a plate of CsI(Tl) scintillator coupled to a photomultiplier
tube, can locate a point source of gamma rays with degree-scale precision by
comparing the count rates in the different modules. Sensitivity to uniform
environmental background is minimal.
