JET neutron cameras detect both D-D 2.5MeV and D-T 14MeV fusion neutrons along 19 lines of sight (see in Fig.1). This instrument, unique among similar diagnostics available at large fusion research facilities has a coarse spatial resolution of 15cm and a time resolution currently of 10ms. Both sets of detectors are absolutely calibrated at 2.5MeV for D-D and 14MeV for D-T. The full potential of JET neutron cameras is best exploited from the diagnostic point of view in the trace tritium experiments.