A detection apparatus usable to detect a neutron absorption capability of a control element of a nuclear installation, the detection apparatus comprising: a processor apparatus comprising a processor and a storage; a robot apparatus in communication with the processor apparatus and comprising a number of manipulators; a neutron radiograph apparatus comprising an neutron emission source, a detector array, and a mask apparatus, the neutron radiograph apparatus being structured to receive the control element generally between the neutron emission source and the detector array; the neutron emission source being switchable between an ON state and an OFF state, the neutron emission source in the ON state being in an electrically energized condition structured to generate a neutron stream, the neutron emission source in the OFF state being in an electrically de-energized condition structured to output no meaningful neutron stream; the detector array being structured to detect an unabsorbed portion the neutron stream that passes without being absorbed through the control element, the detector array being further structured to generate an output signal that is representative of the unabsorbed portion the neutron stream; characterised in that the mask apparatus is movable by at least a first manipulator of the number of manipulators among a number of positions, a position of the number of positions being that in which the mask apparatus is disposed at least partially between the neutron emission source and the detector array, another position of the number of positions being that in which the mask apparatus is removed from between the neutron emission source and the detector array; wherein the mask apparatus comprises a mask system (70, 70A, 70B) having an orifice formed therein, the mask system being structured to generally resist the passage therethrough of the neutron stream but permitting passage of at least a part of the neutron stream through the orifice; and wherein the mask apparatus in the position disposed at least partially between the neutron emission source and the detector array is structured to at least one of block and absorb at least a portion of the neutron stream. a processor apparatus comprising a processor and a storage; a robot apparatus in communication with the processor apparatus and comprising a number of manipulators; a neutron radiograph apparatus comprising an neutron emission source, a detector array, and a mask apparatus, the neutron radiograph apparatus being structured to receive the control element generally between the neutron emission source and the detector array; the neutron emission source being switchable between an ON state and an OFF state, the neutron emission source in the ON state being in an electrically energized condition structured to generate a neutron stream, the neutron emission source in the OFF state being in an electrically de-energized condition structured to output no meaningful neutron stream; the detector array being structured to detect an unabsorbed portion the neutron stream that passes without being absorbed through the control element, the detector array being further structured to generate an output signal that is representative of the unabsorbed portion the neutron stream; characterised in that the mask apparatus is movable by at least a first manipulator of the number of manipulators among a number of positions, a position of the number of positions being that in which the mask apparatus is disposed at least partially between the neutron emission source and the detector array, another position of the number of positions being that in which the mask apparatus is removed from between the neutron emission source and the detector array; wherein the mask apparatus comprises a mask system (70, 70A, 70B) having an orifice formed therein, the mask system being structured to generally resist the passage therethrough of the neutron stream but permitting passage of at least a part of the neutron stream through the orifice; and wherein the mask apparatus in the position disposed at least partially between the neutron emission source and the detector array is structured to at least one of block and absorb at least a portion of the neutron stream.