Abstract: A neutron porosity measurement device adapted to receive a neutron source configured to emit neutrons having a first energy includes a segmented semiconductor detector located at a predetermined distance from the neutron source. The segmented semiconductor detector includes a plurality of semiconductor neutron detection cells configured to detect neutrons having a second energy smaller than the first energy. The cells are arranged in subsets located between a first distance and a second distance from the neutron source, each subset including semiconductor neutron detection cells surrounding an axis and being disposed in opposite sectors defined relative to the axis at substantially same distance from the neutron source. One or more of the neutron detection cells are configured to acquire data related to detected neutrons independently from one or more other of the neutron detected cells. A method of manufacturing the neutron porosity measurement device is also provided.

Abstract: A neutron porosity measurement device adapted to receive a neutron source configured to emit neutrons having a first energy includes a segmented semiconductor detector located at a predetermined distance from the neutron source. The segmented semiconductor detector includes a plurality of semiconductor neutron detection cells configured to detect neutrons having a second energy smaller than the first energy. The cells are arranged in subsets located between a first distance and a second distance from the neutron source, each subset including semiconductor neutron detection cells surrounding an axis and being disposed in opposite sectors defined relative to the axis at substantially same distance from the neutron source. One or more of the neutron detection cells are configured to acquire data related to detected neutrons independently from one or more other of the neutron detected cells. A method of manufacturing the neutron porosity measurement device is also provided.

Abstract: A method and apparatus for detecting ferrous changes passing axially through a cylindrical space. In one embodiment, the method comprises surrounding the cylindrical space with a nonmagnetic cylinder having an outer wall and a cylindrical axis; creating an alternating magnetic field in the cylindrical space, the magnetic field created by a rotatable permanent magnet; monitoring the magnetic field with magnetic flux sensors placed outside the outer walls; and detecting changes in the magnetic field as ferrous matter passes axially through the cylindrical space. In other embodiments, the apparatus identifies ferrous changes as the tool joints that connect a jointed tubing string as the tubing string is moved in or out of a well bore, or as the presence or absence of a coiled tubing string in the well bore.