A radiatively heated crucible having collinear array of channels has been used to produce a long wedgeshaped (length ~100 mm, width ~10 mm) high density (~1011 cm^-3) atomic beam of barium. The collision-free beam flows upwards. The source is designed to generate atomic beams of low melting point (~1000 K) metals and is suitable for long duration (~15 h) operation. The beam, used for laserionized plasma studies, has been characterized by measuring the integrated density of the ground state of barium atoms at a fixed distance away from the source. At the same location the density distribution profiles along the length and width of the beam are also mapped. The measurements are carried out online using hollow cathode lamp based absorption spectroscopy technique and also intrusively by deposition method. The density and its distribution are also estimated theoretically. The data from the two experimental methods and estimates are in agreement within 10% accuracy.