Abstract: A system for detecting hidden edges is disclosed. The system comprises a workpiece having a surface and a hidden edge located below the surface. A radiation source moves along the workpiece surface and generates radiation. A radiation receiver moves along the workpiece surface and receives reflected radiation. A processor coupled to the radiation receiver determines a count rate of the reflected radiation, determines a change of the count rate corresponding to the hidden edge, and associates the change to a position on the workpiece surface. A method for detecting hidden edges is disclosed. Step one calls for providing a workpiece having a surface and a hidden edge located below the surface. Step two provides for directing radiation towards the workpiece surface with a radiation source. At step three, the method calls for receiving reflected radiation with a radiation receiver.

Abstract: A two-dimensional imaging backscatter probe has a radiation source, a radiation detector, and a position sensing device to which the radiation detector is attached. A mapping circuit generates a two-dimensional map of backscattered radiation as a function of position of the radiation detector. A display displays the two-dimensional map. The two-dimensional imaging backscatter probe of the present invention facilitates non-destructive/non-intrusive inspection of a test article for contraband and/or structural integrity inspection.

Abstract: A directional thermal neutron detector for detecting thermal neutrons and determining the direction of the thermal neutron source. The directional detector includes an array of individual thermal neutron detector modules, each of which comprises front and back planar silicon detectors having a gadolinium foil sandwiched therebetween. The array comprises a plurality of individual detector modules which are angularly displaced with respect to each other. The direction of the thermal neutron source is determined by comparing the magnitudes of the output signals from the plurality of angularly displaced detector modules. Each thermal neutron detector module is segmented into four quadrants to reduce its capacitance and resultant noise. The thickness of the gadolinium foil in each thermal neutron detector module is at least 15 microns thick, to improve the front-to-back silicon detector counting ratio to ascertain the side (front or back) from which thermal neutrons are arriving at the detector.

Abstract: The invention utilizes a hydrogen atmosphere during the heat treatment of an Al-Li alloy. The presence of such a reducing atmosphere prevents the reaction of surface lithium atoms with atmosphere components that would cause a diffusion and subsequent depletion of lithium atoms in the region near the surface. As a result, the present invention suppresses lithium loss and consequently prevents the formation of agglomerated lithium atom vacancies which would otherwise develop into microscopic metallic porosity. The prevention of such a condition maintains high fatigue resistance and corrosion resistance in association with metallic strength.

Abstract: A bi-directional neutron detector comprises spaced hydrogenous layers interspersed with stacks of silicon detector layers. The energy loss from each of these layers is read out and a pattern of energy loss corresponds to the direction of travel of the recoil proton.

Abstract: A neutron sensor comprises stacks of multi-layered segments. Each segment includes a first layer having a variable energy threshold for varying the sensitivity of the layer to low energy recoil protons. Immediately adjacent the threshold layer are two directional layers which produce output signals dependent upon the energy loss of recoil protons passing therethrough. The output signals generate a pattern which corresponds to the direction of neutron flow through the sensor.