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Paolo Peerani

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Papers by Paolo Peerani

The Real Time Mass Evaluation System as a tool for the detection of undeclared cascade operation at GCEPs

Nuclear Engineering and Design, 2008

Given the ‡exibility of current cascade designs a real time mass monitoring sys- tem is preferred... more Given the ‡exibility of current cascade designs a real time mass monitoring sys- tem is preferred. However, if such a system is to be installed in a GCEP it must not impinge on plant operation or be intrusive. Since load cells are already part of the operational process and located outside the cascade hall their exploitation for safeguards purposes is

Special nuclear material detection with a mobile multi-detector system

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2012

The detection of special nuclear material has been studied with a mobile inspection system used b... more The detection of special nuclear material has been studied with a mobile inspection system used both as a high sensitivity passive neutron/gamma spectroscopic tool and as an active inspection device using tagged neutrons. The detection of plutonium samples seems to be possible with passive interrogation, even for small samples, thanks to the yield of gamma ray and neutrons. Moreover the gamma ray spectrum shows clear signatures related to 239 Pu. The passive detection of uranium is much more difficult because of the low neutron yield and of the easiness of shielding the gamma ray yield of highly enriched U samples. However, we show that active interrogation with tagged neutrons is able to provide signatures for the discrimination of uranium against other heavy metals.

Pulse-height distributions of neutron and gamma rays from plutonium-oxide samples

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2009

We present new results on neutron and gamma-ray pulse-height distributions (PHDs) measured with l... more We present new results on neutron and gamma-ray pulse-height distributions (PHDs) measured with liquid scintillators from five plutonium-oxide samples of varying mass and burnup and a 252 Cf isotopic source. We show that the analysis of the pulse-height distributions can be used to easily distinguish the fissile material (plutonium oxide) from the 252 Cf source. Moreover, the slope of the measured pulseheight distributions can be analyzed to distinguish the burnup of the samples, independent of their masses. Finally, the measurement scenarios are modeled using the MCNP-PoliMi code and good agreement is observed between the measured and the simulated pulse-height distributions.

Unattended Measurement Station (UMS): Towards the complete Characterisation of fresh LEU Assemblies

by Paolo Peerani and Joao Goncalves

The Joint Research Centre of the European Commission, in collaboration with EURATOM Safeguards, d... more The Joint Research Centre of the European Commission, in collaboration with EURATOM Safeguards, developed an unattended measurement station (UMS) for characterising fresh LEU fuel assemblies. The UMS provides a neutron measurement based on the active neutron coincidence counting technique using an AmLi interrogation source (neutron collar). The system was installed at FBFC-Framatome ANP fabrication plant at Romans-sur-Isère, France, where the assemblies will be verified for gross and/or partial defects. The facility operator places each fuel assembly in the measurement station in the absence of the inspector. The assembly identification number, normally located in the element head, is read by a 2D/3D Laser scanning system integrated into the measurement station. The identification incorporates optical character recognition (OCR) technology to interpret the 2D/3D image. For reviewing purposes, each 2D/3D acquired image is locally archived. The UMS provides unattended service for 100 ...

Integrated Border Management: R&D Activities at JRC

NATO Science for Peace and Security Series B: Physics and Biophysics, 2008

65 S. Apikyan et al. (eds), Prevention, Detection and Response to Nuclear and Radiological Threat... more

Testing on novel neutron detectors as alternative to 3He for security applications

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2012

Detection of illicit trafficking of nuclear material relies on the detection of the radiation emi... more

Neutron and gamma-ray cross-correlation measurements of MOX fuel using liquid scintillators

IEEE Nuclear Science Symposuim & Medical Imaging Conference, 2010

The detection of special nuclear material (SNM) is a very difficult problem: typically, the signa... more The detection of special nuclear material (SNM) is a very difficult problem: typically, the signals are weak thus difficult to distinguish from the background and in many practical applications additional shielding can be expected. In order to detect SNM more accurately, new methods to isolate the source signal are needed. Using cross-correlation functions it may be possible to identify the time-correlated particles from fission events above the background. To examine this feasibility, measurements were performed on 1-kg MOX fuel samples, a 252 Cf source, and an AmBe source. Using pulse shape discrimination the particle types were isolated and the individual correlation contributions were determined. By comparing the (n,n) peak of the correlation curves a distinct difference is observed between a spontaneous fission source and an (α,n) source.

Calibration, characterisation and Monte Carlo modelling of a fast-UNCL

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2012

This paper describes the calibration, characterisation and Monte Carlo modelling of a new IAEA Ur... more This paper describes the calibration, characterisation and Monte Carlo modelling of a new IAEA Uranium Neutron Collar (UNCL) for LWR fuel, which can be operated in both passive and active modes. It can employ either 35 3 He tubes (in active configuration) or 44 tubes at 10 atm pressure (in its passive configuration) and thus can be operated in fast mode (with Cd liner) as its efficiency is higher than that of the standard UNCL. Furthermore, it has an adjustable internal cavity which allows the measurement of varying sizes of fuel assemblies such as WWER, PWR and BWR. It is intended to be used with Cd liners in active mode (with an AmLi interrogation source in place) by the inspectorate for the determination of the 235 U content in fresh fuel assemblies, especially in cases where high concentrations of burnable poisons cause problems with accurate assays.

Scanning Cargo Containers with Tagged Neutrons

by Vladivoj Valkovic, Karlo Nad, Davorin Sudac, Paolo Peerani, and M. Lunardon

A new Tagged Neutron Inspection System (TNIS) able to detect illicit materials such as explosives... more A new Tagged Neutron Inspection System (TNIS) able to detect illicit materials such as explosives and narcotics in cargo containers has been developed within the EURopean Illicit TRAfficing Countermeasures Kit (EURITRACK) project. After the R&D phase, the inspection portal has been installed and commissioned at the Rijeka seaport in Croatia, where it has been operated in connection with the existing X‐ray scanner for a first two‐month demonstration campaign. Results obtained are presented and discussed in this paper.

Defense and Security Symposium

by Vladivoj Valkovic, Paolo Peerani, and M. Lunardon

The EURopean Illicit TRAfficing Countermeasures Kit project is part of the 6th European Union Fra... more The EURopean Illicit TRAfficing Countermeasures Kit project is part of the 6th European Union Framework Program, and aims at developing a neutron inspection system for detecting threat materials (explosives, drugs, etc.) in cargo containers. Neutron interaction in the container produces specific gamma-rays used to determine the chemical composition of the inspected material. An associated particle sealed tube neutron generator is developed to allow precise location of the interaction point by direction and time-of-flight measurements of the neutrons tagged by alpha-particles. The EURITRACK project consists in developing: a transportable deuterium-tritium neutron generator including a position sensitive alpha detector (8×8 matrix of YAP:Ce crystals coupled to a multi-anode photomultiplier), fast neutron and gamma-ray detectors, front-end electronics to perform coincidence and spectroscopic measurements, and an integrated software which manages neutron generator and detectors position...

In-field tests of the EURITRACK tagged neutron inspection system

by Paolo Peerani, B. Perot, Davorin Sudac, and S. Bernard

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2008

The EURopean Illicit TRAfficking Countermeasures Kit (EURITRACK) inspection system has been desig... more The EURopean Illicit TRAfficking Countermeasures Kit (EURITRACK) inspection system has been designed to complement X-ray scanners in the detection of explosives and other illicit materials hidden in cargo containers. The containers are interrogated by a 14-MeV tagged neutron beam at any suspect position in the X-ray image. Interrogation of a specific volume element with tagged neutrons yields information about the

PASSIVE (NMIS) MEASUREMENTS ON PLUTONIUM OXIDE SAMPLES

This paper describes the measurements and Monte Carlo simulations that were performed in March an... more This paper describes the measurements and Monte Carlo simulations that were performed in March and April, 2005 on plutonium oxide standards stored at the EURATOM Joint Research Center in Ispra, Italy. The simulations were performed with the MCNP-PoliMi code, which correctly simulates the statistics of the neutron and photon field in a multiplying medium. The plutonium samples were oxide powder

Performance of an active well coincidence counter for HEU samples

Radiation Measurements, 2010

Neutron coincidence counting is the reference NDA technique used in nuclear safeguards to measure... more Neutron coincidence counting is the reference NDA technique used in nuclear safeguards to measure the mass of nuclear material in samples. For high-enriched uranium (HEU) samples active neutron interrogation is generally performed and the most common device used by nuclear inspectors is the Active Well Coincidence Counter (AWCC).

Review of the European project - Impact of accelerator-based technologies on nuclear fission safety (IABAT)

Progress in Nuclear Energy, 2001

The IABAT project -Impact of Accelerator Based Technologies on Nuclear Fission Safety -started in... more The IABAT project -Impact of Accelerator Based Technologies on Nuclear Fission Safety -started in 1996 in the frame of 4 th Framework Programme of the European Union, R&D specific programme "Nuclear fission safety 1994-1998", area A.2 "Exploring innovative approaches/Fuel cycle concepts," as one of the first common European activities in ADS. The project was completed October 31, 1999. The overall objective of the IABAT project has been a preliminary assessment of the potential of Accelerator-Driven Systems (ADS) for transmutation of nuclear waste and for nuclear energy production with minimum waste generation. Moreover, more specific topics related to nuclear data and code development for ADS have been studied in more detail. Four ADSs have been studied for different fuel/coolant combinations: liquid metal coolant and solid fuel, liquid metal coolant and dispersed fuel, and fast and thermal molten salt sy~ems. Target studies comprised multiple target solutions and radiation damage problems in a target environment. In a tool development part of the project a methodology of subcriticality monitoring has been developed based on Feynman-alpha and Rossi-alpha methods. Moreover, a new Monte-Carlo 135 136 W. Gudowski et al. burnup code taking full advantage of continuous neutron cross-section data "has been developed and benchmarked. Impact on the risk from high-level waste repositories from radiotoxicity reduction using ADS has been assessed giving no crystal-clear benefits of ADS for repository radiotoxicity reduction but concluding some important prerequisites for effective transmutation. In proliferation studies important differences between critical reactors and ADS have been underlined and non-proliferation measures have been proposed. In assessment of accelerator technology costing models have been created that allow the circular and linear accelerator options to be compared and the effect of parameter variations examined. The calculations reported show that cyclotron systems would be more economical, due mainly to the advantage of the cost of RF power supplies. However, the accelerator community regards with skepticism the possibility of transporting and extracting more than a 10mA beam current from a 1GeV cyclotron and therefore technical factors may limit the application of cyclotrons. Finally, this review summarizes development of nuclear data in the energy region between 20 Mev and 150 MeV. Neutron and proton transport data files for Fe, Ni, Pb, Th,/3SU and 239pu have been created. The high-energy part of the data files consists completely of results from model calculations, which are benchmarked against the available experimental data. Although there is obviously future work lett regarding t'me-tuning of several parts of the data files, the representation of nuclear reaction information up to 150 MeV is already better than can be attained with intranuclear cascade codes.

Characterisation of proportional counters

by Paolo Peerani and Marc Roberto Looman

Radiation Measurements, 2006

This paper describes the characterisation of a set of 3 He proportional counters differing in gas... more This paper describes the characterisation of a set of 3 He proportional counters differing in gas composition and pressure. Each step of the signal generation in the detector is analysed. Optimal working conditions are defined in order to choose the high voltage to be applied. Dead time with short shaping time is measured in such optimal conditions. In addition, the overall neutron efficiency and the gamma sensitivity are reported. Such characterisation is required for a correct choice of the associated counting electronics and the applications of the counters.

Real-time simulation of neutron counters

by Paolo Peerani and Marc Roberto Looman

Radiation Measurements, 2008

In this paper we discuss the long-term perspective of the application of numerical modelling to n... more In this paper we discuss the long-term perspective of the application of numerical modelling to neutron (coincidence or multiplicity) counting. The advantage of this technique for nuclear safeguards is discussed with particular emphasis to the numerical calibration of detectors. As a particular case of numerical modelling, real-time simulation would allow overcoming some problems related to precalibration of neutron counters, especially in all those cases when the sample characteristics deviate from the calibration conditions. Nevertheless it requires a significant increase in computing capabilities. The requirements for real-time simulations deriving from inspection needs are discussed and compared to current (and possible future) computing capabilities.

Development of the EURITRACK tagged neutron inspection system

by Vladivoj Valkovic, Davorin Sudac, Paolo Peerani, and M. Lunardon

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2007

The EURopean Illicit TRAfficing Countermeasures Kit (EURITRACK) project is part of the 6th Europe... more The EURopean Illicit TRAfficing Countermeasures Kit (EURITRACK) project is part of the 6th European Union Framework Program. It aims at developing a Tagged Neutron Inspection System (TNIS) to detect illicit materials, such as explosives and narcotics, in cargo containers. Fast neutron induced reactions produce specific gamma-rays used to determine the chemical composition of the inspected material. The associated particle technique is employed to precisely locate the interaction points of the neutrons. A new deuterium-tritium neutron generator has been developed, including a pixelized alpha particle detector. The TNIS also comprises high-efficiency fast neutron and gamma-ray detectors, a dedicated front-end electronics and an integrated software to entirely drive the system and automatically process the data. Most components have been integrated during last months at Institute Ruder Boskovic, in Zagreb, Croatia. An overview of the TNIS and of its preliminary performances is presented.

Front-end electronics and DAQ for the EURITRACK tagged neutron inspection system

by Vladivoj Valkovic, Davorin Sudac, Paolo Peerani, and M. Lunardon

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2007

The EURopean Illicit TRAfficing Countermeasures Kit (EURITRACK) Front-End and Data Acquisition Sy... more The EURopean Illicit TRAfficing Countermeasures Kit (EURITRACK) Front-End and Data Acquisition System is a compact set of VME boards interfaced with a standard PC. The system is part of a cargo container inspection portal based on the tagged neutrons technique. The front-end processes all detector signals and checks coincidences between any of the 64 pixels of the alpha particle detector and any gamma-ray signals in 22 NaI(Tl) scintillators. The system is capable of handling the data flow at neutron flux up to the portal limiting value of 10 8 neutrons/second. Some typical applications are presented.

Neutron spectroscopy of plutonium oxide using matrix unfolding approach

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2010

The knowledge of a neutron energy spectrum is extremely valuable in nuclear non-proliferation and... more The knowledge of a neutron energy spectrum is extremely valuable in nuclear non-proliferation and safeguards applications. Unfortunately, conventional gas and fission-type detectors are not adapted to determine incident neutron energy. As a result, a matrix inversion technique was implemented to generate desirable and consistent neutron energy spectra from an EJ-309 liquid scintillator. To overcome the ill-posed unfolded solutions, the method of sequential least squares is reviewed briefly, and the conditions under which it is used are stated. From the analysis, unfolded energy spectra solutions of five distinct PuO 2 fuel samples and a 252 Cf source are presented and compared to the simulated unfolded and reference energy distributions.

Neutron and gamma-ray cross-correlation measurements of plutonium oxide powder

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2009

For the first time, measurements of the time-dependent cross-correlation distributions of plutoni... more For the first time, measurements of the time-dependent cross-correlation distributions of plutonium oxide have been made separately for neutrons and gamma rays. Six EJ-309 liquid scintillation detectors with a digital, offline pulse shape discrimination and pulse timing method were used to measure five different samples of varying mass and burnup. The number of (neutron, neutron) correlations were selectively analyzed versus plutonium mass and a clear, increasing trend was observed. Additionally, the measurement scenarios were modeled using the MCNP-PoliMi code and good agreement was observed between the measured and simulated cross-correlation functions.

The Real Time Mass Evaluation System as a tool for the detection of undeclared cascade operation at GCEPs

Nuclear Engineering and Design, 2008

Given the ‡exibility of current cascade designs a real time mass monitoring sys- tem is preferred... more Given the ‡exibility of current cascade designs a real time mass monitoring sys- tem is preferred. However, if such a system is to be installed in a GCEP it must not impinge on plant operation or be intrusive. Since load cells are already part of the operational process and located outside the cascade hall their exploitation for safeguards purposes is

Special nuclear material detection with a mobile multi-detector system

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2012

The detection of special nuclear material has been studied with a mobile inspection system used b... more The detection of special nuclear material has been studied with a mobile inspection system used both as a high sensitivity passive neutron/gamma spectroscopic tool and as an active inspection device using tagged neutrons. The detection of plutonium samples seems to be possible with passive interrogation, even for small samples, thanks to the yield of gamma ray and neutrons. Moreover the gamma ray spectrum shows clear signatures related to 239 Pu. The passive detection of uranium is much more difficult because of the low neutron yield and of the easiness of shielding the gamma ray yield of highly enriched U samples. However, we show that active interrogation with tagged neutrons is able to provide signatures for the discrimination of uranium against other heavy metals.

Pulse-height distributions of neutron and gamma rays from plutonium-oxide samples

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2009

We present new results on neutron and gamma-ray pulse-height distributions (PHDs) measured with l... more We present new results on neutron and gamma-ray pulse-height distributions (PHDs) measured with liquid scintillators from five plutonium-oxide samples of varying mass and burnup and a 252 Cf isotopic source. We show that the analysis of the pulse-height distributions can be used to easily distinguish the fissile material (plutonium oxide) from the 252 Cf source. Moreover, the slope of the measured pulseheight distributions can be analyzed to distinguish the burnup of the samples, independent of their masses. Finally, the measurement scenarios are modeled using the MCNP-PoliMi code and good agreement is observed between the measured and the simulated pulse-height distributions.

Unattended Measurement Station (UMS): Towards the complete Characterisation of fresh LEU Assemblies

by Paolo Peerani and Joao Goncalves

The Joint Research Centre of the European Commission, in collaboration with EURATOM Safeguards, d... more The Joint Research Centre of the European Commission, in collaboration with EURATOM Safeguards, developed an unattended measurement station (UMS) for characterising fresh LEU fuel assemblies. The UMS provides a neutron measurement based on the active neutron coincidence counting technique using an AmLi interrogation source (neutron collar). The system was installed at FBFC-Framatome ANP fabrication plant at Romans-sur-Isère, France, where the assemblies will be verified for gross and/or partial defects. The facility operator places each fuel assembly in the measurement station in the absence of the inspector. The assembly identification number, normally located in the element head, is read by a 2D/3D Laser scanning system integrated into the measurement station. The identification incorporates optical character recognition (OCR) technology to interpret the 2D/3D image. For reviewing purposes, each 2D/3D acquired image is locally archived. The UMS provides unattended service for 100 ...

Integrated Border Management: R&D Activities at JRC

NATO Science for Peace and Security Series B: Physics and Biophysics, 2008

65 S. Apikyan et al. (eds), Prevention, Detection and Response to Nuclear and Radiological Threat... more

Testing on novel neutron detectors as alternative to 3He for security applications

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2012

Detection of illicit trafficking of nuclear material relies on the detection of the radiation emi... more

Neutron and gamma-ray cross-correlation measurements of MOX fuel using liquid scintillators

IEEE Nuclear Science Symposuim & Medical Imaging Conference, 2010

The detection of special nuclear material (SNM) is a very difficult problem: typically, the signa... more The detection of special nuclear material (SNM) is a very difficult problem: typically, the signals are weak thus difficult to distinguish from the background and in many practical applications additional shielding can be expected. In order to detect SNM more accurately, new methods to isolate the source signal are needed. Using cross-correlation functions it may be possible to identify the time-correlated particles from fission events above the background. To examine this feasibility, measurements were performed on 1-kg MOX fuel samples, a 252 Cf source, and an AmBe source. Using pulse shape discrimination the particle types were isolated and the individual correlation contributions were determined. By comparing the (n,n) peak of the correlation curves a distinct difference is observed between a spontaneous fission source and an (α,n) source.

Calibration, characterisation and Monte Carlo modelling of a fast-UNCL

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2012

This paper describes the calibration, characterisation and Monte Carlo modelling of a new IAEA Ur... more This paper describes the calibration, characterisation and Monte Carlo modelling of a new IAEA Uranium Neutron Collar (UNCL) for LWR fuel, which can be operated in both passive and active modes. It can employ either 35 3 He tubes (in active configuration) or 44 tubes at 10 atm pressure (in its passive configuration) and thus can be operated in fast mode (with Cd liner) as its efficiency is higher than that of the standard UNCL. Furthermore, it has an adjustable internal cavity which allows the measurement of varying sizes of fuel assemblies such as WWER, PWR and BWR. It is intended to be used with Cd liners in active mode (with an AmLi interrogation source in place) by the inspectorate for the determination of the 235 U content in fresh fuel assemblies, especially in cases where high concentrations of burnable poisons cause problems with accurate assays.

Scanning Cargo Containers with Tagged Neutrons

by Vladivoj Valkovic, Karlo Nad, Davorin Sudac, Paolo Peerani, and M. Lunardon

A new Tagged Neutron Inspection System (TNIS) able to detect illicit materials such as explosives... more A new Tagged Neutron Inspection System (TNIS) able to detect illicit materials such as explosives and narcotics in cargo containers has been developed within the EURopean Illicit TRAfficing Countermeasures Kit (EURITRACK) project. After the R&D phase, the inspection portal has been installed and commissioned at the Rijeka seaport in Croatia, where it has been operated in connection with the existing X‐ray scanner for a first two‐month demonstration campaign. Results obtained are presented and discussed in this paper.

Defense and Security Symposium

by Vladivoj Valkovic, Paolo Peerani, and M. Lunardon

The EURopean Illicit TRAfficing Countermeasures Kit project is part of the 6th European Union Fra... more The EURopean Illicit TRAfficing Countermeasures Kit project is part of the 6th European Union Framework Program, and aims at developing a neutron inspection system for detecting threat materials (explosives, drugs, etc.) in cargo containers. Neutron interaction in the container produces specific gamma-rays used to determine the chemical composition of the inspected material. An associated particle sealed tube neutron generator is developed to allow precise location of the interaction point by direction and time-of-flight measurements of the neutrons tagged by alpha-particles. The EURITRACK project consists in developing: a transportable deuterium-tritium neutron generator including a position sensitive alpha detector (8×8 matrix of YAP:Ce crystals coupled to a multi-anode photomultiplier), fast neutron and gamma-ray detectors, front-end electronics to perform coincidence and spectroscopic measurements, and an integrated software which manages neutron generator and detectors position...

In-field tests of the EURITRACK tagged neutron inspection system

by Paolo Peerani, B. Perot, Davorin Sudac, and S. Bernard

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2008

The EURopean Illicit TRAfficking Countermeasures Kit (EURITRACK) inspection system has been desig... more The EURopean Illicit TRAfficking Countermeasures Kit (EURITRACK) inspection system has been designed to complement X-ray scanners in the detection of explosives and other illicit materials hidden in cargo containers. The containers are interrogated by a 14-MeV tagged neutron beam at any suspect position in the X-ray image. Interrogation of a specific volume element with tagged neutrons yields information about the

PASSIVE (NMIS) MEASUREMENTS ON PLUTONIUM OXIDE SAMPLES

This paper describes the measurements and Monte Carlo simulations that were performed in March an... more This paper describes the measurements and Monte Carlo simulations that were performed in March and April, 2005 on plutonium oxide standards stored at the EURATOM Joint Research Center in Ispra, Italy. The simulations were performed with the MCNP-PoliMi code, which correctly simulates the statistics of the neutron and photon field in a multiplying medium. The plutonium samples were oxide powder

Performance of an active well coincidence counter for HEU samples

Radiation Measurements, 2010

Neutron coincidence counting is the reference NDA technique used in nuclear safeguards to measure... more Neutron coincidence counting is the reference NDA technique used in nuclear safeguards to measure the mass of nuclear material in samples. For high-enriched uranium (HEU) samples active neutron interrogation is generally performed and the most common device used by nuclear inspectors is the Active Well Coincidence Counter (AWCC).

Review of the European project - Impact of accelerator-based technologies on nuclear fission safety (IABAT)

Progress in Nuclear Energy, 2001

The IABAT project -Impact of Accelerator Based Technologies on Nuclear Fission Safety -started in... more The IABAT project -Impact of Accelerator Based Technologies on Nuclear Fission Safety -started in 1996 in the frame of 4 th Framework Programme of the European Union, R&D specific programme "Nuclear fission safety 1994-1998", area A.2 "Exploring innovative approaches/Fuel cycle concepts," as one of the first common European activities in ADS. The project was completed October 31, 1999. The overall objective of the IABAT project has been a preliminary assessment of the potential of Accelerator-Driven Systems (ADS) for transmutation of nuclear waste and for nuclear energy production with minimum waste generation. Moreover, more specific topics related to nuclear data and code development for ADS have been studied in more detail. Four ADSs have been studied for different fuel/coolant combinations: liquid metal coolant and solid fuel, liquid metal coolant and dispersed fuel, and fast and thermal molten salt sy~ems. Target studies comprised multiple target solutions and radiation damage problems in a target environment. In a tool development part of the project a methodology of subcriticality monitoring has been developed based on Feynman-alpha and Rossi-alpha methods. Moreover, a new Monte-Carlo 135 136 W. Gudowski et al. burnup code taking full advantage of continuous neutron cross-section data "has been developed and benchmarked. Impact on the risk from high-level waste repositories from radiotoxicity reduction using ADS has been assessed giving no crystal-clear benefits of ADS for repository radiotoxicity reduction but concluding some important prerequisites for effective transmutation. In proliferation studies important differences between critical reactors and ADS have been underlined and non-proliferation measures have been proposed. In assessment of accelerator technology costing models have been created that allow the circular and linear accelerator options to be compared and the effect of parameter variations examined. The calculations reported show that cyclotron systems would be more economical, due mainly to the advantage of the cost of RF power supplies. However, the accelerator community regards with skepticism the possibility of transporting and extracting more than a 10mA beam current from a 1GeV cyclotron and therefore technical factors may limit the application of cyclotrons. Finally, this review summarizes development of nuclear data in the energy region between 20 Mev and 150 MeV. Neutron and proton transport data files for Fe, Ni, Pb, Th,/3SU and 239pu have been created. The high-energy part of the data files consists completely of results from model calculations, which are benchmarked against the available experimental data. Although there is obviously future work lett regarding t'me-tuning of several parts of the data files, the representation of nuclear reaction information up to 150 MeV is already better than can be attained with intranuclear cascade codes.

Characterisation of proportional counters

by Paolo Peerani and Marc Roberto Looman

Radiation Measurements, 2006

This paper describes the characterisation of a set of 3 He proportional counters differing in gas... more This paper describes the characterisation of a set of 3 He proportional counters differing in gas composition and pressure. Each step of the signal generation in the detector is analysed. Optimal working conditions are defined in order to choose the high voltage to be applied. Dead time with short shaping time is measured in such optimal conditions. In addition, the overall neutron efficiency and the gamma sensitivity are reported. Such characterisation is required for a correct choice of the associated counting electronics and the applications of the counters.

Real-time simulation of neutron counters

by Paolo Peerani and Marc Roberto Looman

Radiation Measurements, 2008

In this paper we discuss the long-term perspective of the application of numerical modelling to n... more In this paper we discuss the long-term perspective of the application of numerical modelling to neutron (coincidence or multiplicity) counting. The advantage of this technique for nuclear safeguards is discussed with particular emphasis to the numerical calibration of detectors. As a particular case of numerical modelling, real-time simulation would allow overcoming some problems related to precalibration of neutron counters, especially in all those cases when the sample characteristics deviate from the calibration conditions. Nevertheless it requires a significant increase in computing capabilities. The requirements for real-time simulations deriving from inspection needs are discussed and compared to current (and possible future) computing capabilities.

Development of the EURITRACK tagged neutron inspection system

by Vladivoj Valkovic, Davorin Sudac, Paolo Peerani, and M. Lunardon

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2007

The EURopean Illicit TRAfficing Countermeasures Kit (EURITRACK) project is part of the 6th Europe... more The EURopean Illicit TRAfficing Countermeasures Kit (EURITRACK) project is part of the 6th European Union Framework Program. It aims at developing a Tagged Neutron Inspection System (TNIS) to detect illicit materials, such as explosives and narcotics, in cargo containers. Fast neutron induced reactions produce specific gamma-rays used to determine the chemical composition of the inspected material. The associated particle technique is employed to precisely locate the interaction points of the neutrons. A new deuterium-tritium neutron generator has been developed, including a pixelized alpha particle detector. The TNIS also comprises high-efficiency fast neutron and gamma-ray detectors, a dedicated front-end electronics and an integrated software to entirely drive the system and automatically process the data. Most components have been integrated during last months at Institute Ruder Boskovic, in Zagreb, Croatia. An overview of the TNIS and of its preliminary performances is presented.

Front-end electronics and DAQ for the EURITRACK tagged neutron inspection system

by Vladivoj Valkovic, Davorin Sudac, Paolo Peerani, and M. Lunardon

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2007

The EURopean Illicit TRAfficing Countermeasures Kit (EURITRACK) Front-End and Data Acquisition Sy... more The EURopean Illicit TRAfficing Countermeasures Kit (EURITRACK) Front-End and Data Acquisition System is a compact set of VME boards interfaced with a standard PC. The system is part of a cargo container inspection portal based on the tagged neutrons technique. The front-end processes all detector signals and checks coincidences between any of the 64 pixels of the alpha particle detector and any gamma-ray signals in 22 NaI(Tl) scintillators. The system is capable of handling the data flow at neutron flux up to the portal limiting value of 10 8 neutrons/second. Some typical applications are presented.

Neutron spectroscopy of plutonium oxide using matrix unfolding approach

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2010

The knowledge of a neutron energy spectrum is extremely valuable in nuclear non-proliferation and... more The knowledge of a neutron energy spectrum is extremely valuable in nuclear non-proliferation and safeguards applications. Unfortunately, conventional gas and fission-type detectors are not adapted to determine incident neutron energy. As a result, a matrix inversion technique was implemented to generate desirable and consistent neutron energy spectra from an EJ-309 liquid scintillator. To overcome the ill-posed unfolded solutions, the method of sequential least squares is reviewed briefly, and the conditions under which it is used are stated. From the analysis, unfolded energy spectra solutions of five distinct PuO 2 fuel samples and a 252 Cf source are presented and compared to the simulated unfolded and reference energy distributions.

Neutron and gamma-ray cross-correlation measurements of plutonium oxide powder

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2009

For the first time, measurements of the time-dependent cross-correlation distributions of plutoni... more For the first time, measurements of the time-dependent cross-correlation distributions of plutonium oxide have been made separately for neutrons and gamma rays. Six EJ-309 liquid scintillation detectors with a digital, offline pulse shape discrimination and pulse timing method were used to measure five different samples of varying mass and burnup. The number of (neutron, neutron) correlations were selectively analyzed versus plutonium mass and a clear, increasing trend was observed. Additionally, the measurement scenarios were modeled using the MCNP-PoliMi code and good agreement was observed between the measured and simulated cross-correlation functions.