A method and system to identify an isotope provided in a medium to be characterized by an instrumentation system. The identification method includes: measuring at least one reference spectrum for at least two reference isotopes; defining measurement windows for each reference isotope; measuring a measured spectrum on the medium to be characterized; for each reference isotope, calculating for each of the measurement windows a deviation value representing the deviation between the measured spectrum and that of the reference isotope in the measurement window; for each reference isotope, determining from the calculated deviation values a dissimilarity coefficient; and identifying the isotope from the determined dissimilarity coefficients.

A discriminator (118) includes a set of comparators (120, 202.sub.1, 202.sub.3, . . . , 202.sub.N), a window width generator (124, 214, 214.sub.1, . . . , 214.sub.N), and a set of reference signal generators (122, 212.sub.1, 212.sub.2, 212.sub.3, . . . , 212.sub.N). In response to the discriminator being in a window based spectrum measurement mode, a first reference signal generator for a first comparator generates a reference signal that is supplied to the first comparator and that is added with the window width with a result of the addition supplied to the second comparator. The first comparator compares a peak height of a pulse indicative of an energy of detected radiation with the supplied reference signal and produces a first output indicating which of the peak height or the reference signal is greater. The second comparator compares the peak height with the supplied result of the addition and produces a second output indicating which of the peak height or the result of the addition is greater.

A discriminator (118) includes a set of comparators (120, 202.sub.1, 202.sub.3, . . . , 202.sub.N), a window width generator (124, 214, 214.sub.1, . . . , 214.sub.N), and a set of reference signal generators (122, 212.sub.1, 212.sub.2, 212.sub.3, . . . , 212.sub.N). In response to the discriminator being in a window based spectrum measurement mode, a first reference signal generator for a first comparator generates a reference signal that is supplied to the first comparator and that is added with the window width with a result of the addition supplied to the second comparator. The first comparator compares a peak height of a pulse indicative of an energy of detected radiation with the supplied reference signal and produces a first output indicating which of the peak height or the reference signal is greater. The second comparator compares the peak height with the supplied result of the addition and produces a second output indicating which of the peak height or the result of the addition is greater.

This application discloses a method and an apparatus for processing a nuclear energy spectrum. The apparatus includes: a detector, a nuclear pulse processing module, and a nuclear energy spectrum processing module; the detector is configured to detect nuclear radiation and convert the nuclear radiation into nuclear pulse signals with corresponding amplitudes; the nuclear pulse processing module is configured to shape the nuclear pulse signals into narrow pulses, and perform amplitude analysis on the narrow pulses to generate the nuclear energy spectrum; the nuclear energy spectrum processing module is configured to reduce a value of an energy resolution of the nuclear energy spectrum to obtain the nuclear energy spectrum with the energy resolution of the reduced value.

This application discloses a method and an apparatus for processing a nuclear energy spectrum. The apparatus includes: a detector, a nuclear pulse processing module, and a nuclear energy spectrum processing module; the detector is configured to detect nuclear radiation and convert the nuclear radiation into nuclear pulse signals with corresponding amplitudes; the nuclear pulse processing module is configured to shape the nuclear pulse signals into narrow pulses, and perform amplitude analysis on the narrow pulses to generate the nuclear energy spectrum; the nuclear energy spectrum processing module is configured to reduce a value of an energy resolution of the nuclear energy spectrum to obtain the nuclear energy spectrum with the energy resolution of the reduced value.

A method for analysing at least one fuel rod comprising a stack of nuclear fuel, a rod comprising packed zones completely filled with fuel and intermediate zones partially full of fuel, comprises: acquiring a count profile associated with a non-migrating isotope, a profile being made up of spectrometry measurements taken along the rod for this isotope; determining a set of at least one indicator K_i that makes it possible to quantify the reduction in material at an intermediate zone of index i, the said indicator being deduced from the count profile; detecting the change in geometry by comparing the set of at least one indicator K_i against a set of at least one reference value RK indicative of the initial geometry of the nuclear fuel stack.

A method for analysing at least one fuel rod comprising a stack of nuclear fuel, a rod comprising packed zones completely filled with fuel and intermediate zones partially full of fuel, comprises: acquiring a count profile associated with a non-migrating isotope, a profile being made up of spectrometry measurements taken along the rod for this isotope; determining a set of at least one indicator K_i that makes it possible to quantify the reduction in material at an intermediate zone of index i, the said indicator being deduced from the count profile; detecting the change in geometry by comparing the set of at least one indicator K_i against a set of at least one reference value RK indicative of the initial geometry of the nuclear fuel stack.

A method for x-ray photon-counting data correction. The method includes generating, by a training data generation module, training input spectral projection data based, at least in part, on a reference spectral projection data. The training input spectral projection data includes at least one of a pulse pileup distortion, a charge splitting distortion, and/or noise. The method further includes training, by a training module, a data correction artificial neural network (ANN) based, at least in part, on training data. The data correction ANN includes a pulse pileup correction ANN, and a charge splitting correction ANN. The training data includes the training input spectral projection data and the reference spectral projection data.

A method for x-ray photon-counting data correction. The method includes generating, by a training data generation module, training input spectral projection data based, at least in part, on a reference spectral projection data. The training input spectral projection data includes at least one of a pulse pileup distortion, a charge splitting distortion, and/or noise. The method further includes training, by a training module, a data correction artificial neural network (ANN) based, at least in part, on training data. The data correction ANN includes a pulse pileup correction ANN, and a charge splitting correction ANN. The training data includes the training input spectral projection data and the reference spectral projection data.

Radiation source localization systems and related techniques are provided to improve the operation of handheld or unmanned mobile sensor or survey platforms. A radiation source localization system includes a logic device configured to communicate with a communications module and a directional radiation detector, where the communications module is configured to establish a wireless communication link with a base station associated with the directional radiation detector and/or a mobile sensor platform, and the directional radiation detector includes a sensor assembly configured to provide directional radiation sensor data as the directional radiation detector is maneuvered within a survey area.