Pulsed source for non-destructive testing by neutrongraphy

The pulsed source described uses the burst of neutrons produced when bringing momentarily a homogeneous fissile solution into a supercritical state. The solution is enclosed in a cylindrical vessel in a subcritical configuration. The supercritical state is reached by bringing a movable neutron reflector up to the bottom of the vessel. The reaction is stopped by bringing the reflector back to its initial position. The source is surrounded by a concrete biologcal shield through which the neutron collimators are built. The burst duration is approximately 2 minutes. The integrated thermal neutron flux at the exposure window of a 180 cm long collimator having a 2 x 3 cm rectangular input window is 2.1 x 10/sup 8/n cm/sup -2/. (auth)