A neutron detector that indicates the direction toward a neutron source. The detector is a proton-recoil type of detector, in which two different scintillators are positioned on both sides of a hydrogenous target. Proton recoil signals from the two scintillators indicate whether neutrons arrive from the left, right, or center relative to the detector alignment. Surprisingly high precision can be obtained by orienting the detector so that the counting rates in the two scintillators are equal, at which point the target layer is directly aligned with the source. Disclosed are thick and thin target configurations, versions for discriminating pulses from the two scintillators, options for assembling a multi-detector stack and array, and multiple analysis procedures for optimally locating the neutron source.

A method of determining radiation exposure during a criticality excursion of a dosimeter having at least one fluorescent nuclear track detector (FNTD) element includes determining the power spectrum integral (PSI) value of the fluorescent images obtained from FNTD element at each of a plurality of different depths using laser induced fluorescent microscopy; normalizing the depth profile to the shallowest depth; fitting a double exponential function to the normalized depth profile; determining the median neutron energy from the E=f(1/e) function; and determining a neutron energy dose correction factor (NCF) from the NCF=f(E) function. The neutron dose, D, can then be calculated by dividing absolute value of the neutron-induced PSI by a sensitivity factor S and multiplying it by the neutron energy dose correction factor NCF.

A method of determining radiation exposure during a criticality excursion of a dosimeter having at least one fluorescent nuclear track detector (FNTD) element includes determining the power spectrum integral (PSI) value of the fluorescent images obtained from FNTD element at each of a plurality of different depths using laser induced fluorescent microscopy; normalizing the depth profile to the shallowest depth; fitting a double exponential function to the normalized depth profile; determining the median neutron energy from the E=f(1/e) function; and determining a neutron energy dose correction factor (NCF) from the NCF=f(E) function. The neutron dose, D, can then be calculated by dividing absolute value of the neutron-induced PSI by a sensitivity factor S and multiplying it by the neutron energy dose correction factor NCF.

An apparatus and method for determining a position of a point source arranged in a Positron Emission Tomography (PET) scanner apparatus. The apparatus includes processing circuitry configured to obtain list-mode data generated from a PET scan of the point source, determine a plurality of lines-of-response (LORs) from the obtained list-mode data, determine intersecting pairs of LORs from the determined plurality of LORs, determine corresponding coordinates of intersection points of the determined intersecting pairs of LORs, and determine the position of the point source based on the determined coordinates of the intersections points.

An apparatus and method for determining a position of a point source arranged in a Positron Emission Tomography (PET) scanner apparatus. The apparatus includes processing circuitry configured to obtain list-mode data generated from a PET scan of the point source, determine a plurality of lines-of-response (LORs) from the obtained list-mode data, determine intersecting pairs of LORs from the determined plurality of LORs, determine corresponding coordinates of intersection points of the determined intersecting pairs of LORs, and determine the position of the point source based on the determined coordinates of the intersections points.

A depth peeling based nuclear radiation shield computational mesh generation method and a depth peeling based nuclear radiation shield computational mesh generation system are provided. The method includes: generating an outline pixel matrix of geometries with the depth peeling technique, performing conversion in an image space to obtain outline meshes of the geometries; then obtaining internal meshes of the geometries based on the outline meshes by a scanning line method, so as to fast generate the nuclear radiation shield computational meshes.