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Papers by Alfio Pappalardo

Research paper thumbnail of SiLiF Neutron Counters to Monitor Nuclear Materials in the MICADO Project

Sensors, 2021

In the framework of the MICADO (Measurement and Instrumentation for Cleaning And Decommissioning ... more In the framework of the MICADO (Measurement and Instrumentation for Cleaning And Decommissioning Operations) European Union (EU) project, aimed at the full digitization of low- and intermediate-level radioactive waste management, a set of 32 solid state thermal neutron detectors named SiLiF has been built and characterized. MICADO encompasses a complete active and passive characterization of the radwaste drums with neutrons and gamma rays, followed by a longer-term monitoring phase. The SiLiF detectors are suitable for the monitoring of nuclear materials and can be used around radioactive waste drums possibly containing small quantities of actinides, as well as around spent fuel casks in interim storage or during transportation. Suitable polyethylene moderators can be exploited to better shape the detector response to the expected neutron spectrum, according to Monte Carlo simulations that were performed. These detectors were extensively tested with an AmBe neutron source, and the r...

Research paper thumbnail of Electromagnetic character of the competitive γγ/γ-decay from 137mBa

Nature Communications, 2020

Second-order processes in physics is a research topic focusing attention from several fields worl... more Second-order processes in physics is a research topic focusing attention from several fields worldwide including, for example, non-linear quantum electrodynamics with high-power lasers, neutrinoless double-β decay, and stimulated atomic two-photon transitions. For the electromagnetic nuclear interaction, the observation of the competitive double-γ decay from 137mBa has opened up the nuclear structure field for detailed investigation of second-order processes through the manifestation of off-diagonal nuclear polarisability. Here, we confirm this observation with an 8.7σ significance, and an improved value on the double-photon versus single-photon branching ratio as 2.62 × 10−6(30). Our results, however, contradict the conclusions from the original experiment, where the decay was interpreted to be dominated by a quadrupole-quadrupole component. Here, we find a substantial enhancement in the energy distribution consistent with a dominating octupole-dipole character and a rather small q...

Research paper thumbnail of Pulse-shape analysis for gamma background rejection in thermal neutron radiation using CVD diamond detectors

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2015

Research paper thumbnail of Radioactive Ion Beams at INFN Laboratories

The LNS and the LNL are the two laboratories of INFN devoted to the research on nuclear physics. ... more The LNS and the LNL are the two laboratories of INFN devoted to the research on nuclear physics. Since the 1995 the LNS are involved in the design and construction of the Radioactive Ion Beam facilities called EXCYT. In the early of 2000 the LNL starts a project for second generation RIB facilities called SPES. In the 2004 at the

Research paper thumbnail of Single-photon avalanche photodiodes with integrated quenching resistor

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

Research paper thumbnail of Thin foil-based secondary emission monitor for low intensity, low energy beam profile measurements

Research paper thumbnail of Measurement of the 7Li(γ,t)4He ground-state cross section between Eγ=4.4 and 10 MeV

Research paper thumbnail of A prototype for the on-line monitoring system for nuclear waste storage

Proceedings of XLIX International Winter Meeting on Nuclear Physics — PoS(Bormio 2011), 2011

Research paper thumbnail of An online monitoring system for nuclear waste storage

2009 1st International Conference on Advancements in Nuclear Instrumentation, Measurement Methods and their Applications, 2009

I. INTRODUCTION Among the many issues related to the disposal of short and medium term radioactiv... more I. INTRODUCTION Among the many issues related to the disposal of short and medium term radioactive waste, there is the storage inside suitable sites where a high level of safety must be guaranteed. In order to detect possible leaks of radioactive material and to efficiently ...

Research paper thumbnail of DETERMINATION OF THE Co SOURCE ACTIVITY BY USING THE SUM-PEAK METHOD

The sum-peak method is one of the methods used for absolute activity measurement of radionuclides... more The sum-peak method is one of the methods used for absolute activity measurement of radionuclides emitting gamma-ray photons in coincidence. This method is based on the use of acquired pulse-height distribution data only, without knowledge of the detector efficiencies. In this paper it is shown that by using Monte Carlo techniques for angular correlation corrections, pile-up peaks for corrections of accidental coincidences, low-level discriminator corrections, the activity of the 60Co source can be measured with accuracy and reproducibility below 5% by using spectral data only.

Research paper thumbnail of Verilog-a modeling of Silicon Photo-Multipliers

2016 IEEE International Symposium on Circuits and Systems (ISCAS), 2016

Research paper thumbnail of Silicon detectors for the neutron flux and beam profile measurements of the n_TOF facility at CERN

International Journal of Modern Physics: Conference Series, 2016

Research paper thumbnail of Full Chapter Bonanno

Research paper thumbnail of Properties of Silicon PhotoMultipliers measured at LNS-INFN

Research paper thumbnail of A beam diagnostic multisensor for low energy radioactive beams

Nuclear Instruments and Methods in Physics Research Section a Accelerators Spectrometers Detectors and Associated Equipment, Oct 1, 2010

During the last years the EXotics with CYclotron and Tandem (EXCYT) facility has been developed a... more During the last years the EXotics with CYclotron and Tandem (EXCYT) facility has been developed at LNS—INFN in Catania, in order to produce radioactive ion beams in the energy range accessible to the 15 MV Tandem Van de Graaf accelerator, with intensity around 10 5 particles per second (pps). In order to guarantee quick and precise beam transport procedures, the facility has been equipped with a high sensitivity beam diagnostics, well designed for very low intensity beams. In this paper we describe the features and the experimental results of the device developed for the low energy beam line (10-300 keV) of the facility. Such a multisensor device is mainly based on particle detectors and allows to collect the needed parameters in real time. In particular it can measure the X- Y transverse beam profile and intensity, and can identify the radioisotopes present in the beam.

Research paper thumbnail of Characterization of detectors for the Italian Astronomical Quantum Photometer Project

Http Dx Doi Org 10 1080 09500340802677068, Oct 7, 2010

In the framework of a national collaboration to bring Quantum Optics concepts to Astronomy, we ar... more In the framework of a national collaboration to bring Quantum Optics concepts to Astronomy, we are involved in finding suitable detectors for this novel application. At 'INAF Osservatorio Astrofisico di Catania' and 'INFN – Laboratori Nazionali del Sud' laboratories, measurements of ...

Research paper thumbnail of Geiger Avalanche Photodiodes (G-APDs) and Their Characterization

Research paper thumbnail of High-resolution Time-Of-Flight PET with Depth-Of-Interaction becomes feasible: a proof of principle

In this paper we prove that the choice of a suitable treatment of the scintillator surfaces, alon... more In this paper we prove that the choice of a suitable treatment of the scintillator surfaces, along with suitable photodetectors electronics and specific algorithms for raw data analysis, allow to achieve an optimal tradeoff between energy, time and DOI resolution, thus strongly supporting the feasibility of a prostate TOF- PET probe, MRI compatible, with the required features and performance. In numbers this means a detector element of 1.5mm x 1.5mm x 10mm, achieving at the same time energy resolution around 11.5%, time-of- flight resolution around 150 ps and DOI resolution even below 1 mm. We stress that such a time resolution allows to increase significantly the Noise Equivalent Counting Rate, and consequently improve the image quality and the lesion detection capability. These individual values correspond to the best obtained so far by other groups, but we got all of them simultaneously. In our opinion this proof of principle paves the way to the feasibility of a TOF-PET MRI compatible probe with unprecedented features and performance, not only innovative for prostate radiotracer imaging but possibly also for other organs.

Research paper thumbnail of An imaging technique for detection and absolute calibration of scintillation light

The Review of Scientific Instruments, Mar 1, 2010

Triggered by the need of a detection system to be used in experiments of nuclear fusion in laser-... more Triggered by the need of a detection system to be used in experiments of nuclear fusion in laser-generated plasmas, we developed an imaging technique for the measurement and calibration of the scintillation light yield of scintillating materials. As in such experiments, all the reaction products are generated in an ultrashort time frame, the event-by-event data acquisition scheme is not feasible. As an alternative to the emulsion technique (or the equivalent CR39 sheets) we propose a scintillating screen readout by means of a high performance charge coupled device camera. Even though it is not strictly required in the particular application, this technique allows the absolute calibration of the scintillation light yield.

Research paper thumbnail of Beam imaging in the injection line of the INFN-LNS superconducting cyclotron

Review of Scientific Instruments, 2016

A cheap and efficient diagnostic system for beam monitoring has been recently developed at INFN-L... more A cheap and efficient diagnostic system for beam monitoring has been recently developed at INFN-LNS in Catania. It consists of a high sensitivity CCD camera detecting the light produced by an ion beam hitting the surface of a scintillating screen and a frame grabber for image acquisition. A scintillating screen, developed at INFN-LNS and consisting of a 2 μm BaF2 layer evaporated on an aluminium plate, has been tested by using (20)Ne and (40)Ar beams in the keV energy range. The CAESAR ECR ion source has been used for investigating the influence of the frequency and magnetic field tuning effects, the impact of the microwave injected power, and of the focusing solenoids along the low energy beam transport on the beam shape and current. These tests will allow to better understand the interplay between the plasma and beam dynamics and, moreover, to improve the transport efficiency along the low energy beam line and the matching with the superconducting cyclotron, particularly relevant in view of the expected upgrade of the machine.

Research paper thumbnail of SiLiF Neutron Counters to Monitor Nuclear Materials in the MICADO Project

Sensors, 2021

In the framework of the MICADO (Measurement and Instrumentation for Cleaning And Decommissioning ... more In the framework of the MICADO (Measurement and Instrumentation for Cleaning And Decommissioning Operations) European Union (EU) project, aimed at the full digitization of low- and intermediate-level radioactive waste management, a set of 32 solid state thermal neutron detectors named SiLiF has been built and characterized. MICADO encompasses a complete active and passive characterization of the radwaste drums with neutrons and gamma rays, followed by a longer-term monitoring phase. The SiLiF detectors are suitable for the monitoring of nuclear materials and can be used around radioactive waste drums possibly containing small quantities of actinides, as well as around spent fuel casks in interim storage or during transportation. Suitable polyethylene moderators can be exploited to better shape the detector response to the expected neutron spectrum, according to Monte Carlo simulations that were performed. These detectors were extensively tested with an AmBe neutron source, and the r...

Research paper thumbnail of Electromagnetic character of the competitive γγ/γ-decay from 137mBa

Nature Communications, 2020

Second-order processes in physics is a research topic focusing attention from several fields worl... more Second-order processes in physics is a research topic focusing attention from several fields worldwide including, for example, non-linear quantum electrodynamics with high-power lasers, neutrinoless double-β decay, and stimulated atomic two-photon transitions. For the electromagnetic nuclear interaction, the observation of the competitive double-γ decay from 137mBa has opened up the nuclear structure field for detailed investigation of second-order processes through the manifestation of off-diagonal nuclear polarisability. Here, we confirm this observation with an 8.7σ significance, and an improved value on the double-photon versus single-photon branching ratio as 2.62 × 10−6(30). Our results, however, contradict the conclusions from the original experiment, where the decay was interpreted to be dominated by a quadrupole-quadrupole component. Here, we find a substantial enhancement in the energy distribution consistent with a dominating octupole-dipole character and a rather small q...

Research paper thumbnail of Pulse-shape analysis for gamma background rejection in thermal neutron radiation using CVD diamond detectors

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2015

Research paper thumbnail of Radioactive Ion Beams at INFN Laboratories

The LNS and the LNL are the two laboratories of INFN devoted to the research on nuclear physics. ... more The LNS and the LNL are the two laboratories of INFN devoted to the research on nuclear physics. Since the 1995 the LNS are involved in the design and construction of the Radioactive Ion Beam facilities called EXCYT. In the early of 2000 the LNL starts a project for second generation RIB facilities called SPES. In the 2004 at the

Research paper thumbnail of Single-photon avalanche photodiodes with integrated quenching resistor

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

Research paper thumbnail of Thin foil-based secondary emission monitor for low intensity, low energy beam profile measurements

Research paper thumbnail of Measurement of the 7Li(γ,t)4He ground-state cross section between Eγ=4.4 and 10 MeV

Research paper thumbnail of A prototype for the on-line monitoring system for nuclear waste storage

Proceedings of XLIX International Winter Meeting on Nuclear Physics — PoS(Bormio 2011), 2011

Research paper thumbnail of An online monitoring system for nuclear waste storage

2009 1st International Conference on Advancements in Nuclear Instrumentation, Measurement Methods and their Applications, 2009

I. INTRODUCTION Among the many issues related to the disposal of short and medium term radioactiv... more I. INTRODUCTION Among the many issues related to the disposal of short and medium term radioactive waste, there is the storage inside suitable sites where a high level of safety must be guaranteed. In order to detect possible leaks of radioactive material and to efficiently ...

Research paper thumbnail of DETERMINATION OF THE Co SOURCE ACTIVITY BY USING THE SUM-PEAK METHOD

The sum-peak method is one of the methods used for absolute activity measurement of radionuclides... more The sum-peak method is one of the methods used for absolute activity measurement of radionuclides emitting gamma-ray photons in coincidence. This method is based on the use of acquired pulse-height distribution data only, without knowledge of the detector efficiencies. In this paper it is shown that by using Monte Carlo techniques for angular correlation corrections, pile-up peaks for corrections of accidental coincidences, low-level discriminator corrections, the activity of the 60Co source can be measured with accuracy and reproducibility below 5% by using spectral data only.

Research paper thumbnail of Verilog-a modeling of Silicon Photo-Multipliers

2016 IEEE International Symposium on Circuits and Systems (ISCAS), 2016

Research paper thumbnail of Silicon detectors for the neutron flux and beam profile measurements of the n_TOF facility at CERN

International Journal of Modern Physics: Conference Series, 2016

Research paper thumbnail of Full Chapter Bonanno

Research paper thumbnail of Properties of Silicon PhotoMultipliers measured at LNS-INFN

Research paper thumbnail of A beam diagnostic multisensor for low energy radioactive beams

Nuclear Instruments and Methods in Physics Research Section a Accelerators Spectrometers Detectors and Associated Equipment, Oct 1, 2010

During the last years the EXotics with CYclotron and Tandem (EXCYT) facility has been developed a... more During the last years the EXotics with CYclotron and Tandem (EXCYT) facility has been developed at LNS—INFN in Catania, in order to produce radioactive ion beams in the energy range accessible to the 15 MV Tandem Van de Graaf accelerator, with intensity around 10 5 particles per second (pps). In order to guarantee quick and precise beam transport procedures, the facility has been equipped with a high sensitivity beam diagnostics, well designed for very low intensity beams. In this paper we describe the features and the experimental results of the device developed for the low energy beam line (10-300 keV) of the facility. Such a multisensor device is mainly based on particle detectors and allows to collect the needed parameters in real time. In particular it can measure the X- Y transverse beam profile and intensity, and can identify the radioisotopes present in the beam.

Research paper thumbnail of Characterization of detectors for the Italian Astronomical Quantum Photometer Project

Http Dx Doi Org 10 1080 09500340802677068, Oct 7, 2010

In the framework of a national collaboration to bring Quantum Optics concepts to Astronomy, we ar... more In the framework of a national collaboration to bring Quantum Optics concepts to Astronomy, we are involved in finding suitable detectors for this novel application. At 'INAF Osservatorio Astrofisico di Catania' and 'INFN – Laboratori Nazionali del Sud' laboratories, measurements of ...

Research paper thumbnail of Geiger Avalanche Photodiodes (G-APDs) and Their Characterization

Research paper thumbnail of High-resolution Time-Of-Flight PET with Depth-Of-Interaction becomes feasible: a proof of principle

In this paper we prove that the choice of a suitable treatment of the scintillator surfaces, alon... more In this paper we prove that the choice of a suitable treatment of the scintillator surfaces, along with suitable photodetectors electronics and specific algorithms for raw data analysis, allow to achieve an optimal tradeoff between energy, time and DOI resolution, thus strongly supporting the feasibility of a prostate TOF- PET probe, MRI compatible, with the required features and performance. In numbers this means a detector element of 1.5mm x 1.5mm x 10mm, achieving at the same time energy resolution around 11.5%, time-of- flight resolution around 150 ps and DOI resolution even below 1 mm. We stress that such a time resolution allows to increase significantly the Noise Equivalent Counting Rate, and consequently improve the image quality and the lesion detection capability. These individual values correspond to the best obtained so far by other groups, but we got all of them simultaneously. In our opinion this proof of principle paves the way to the feasibility of a TOF-PET MRI compatible probe with unprecedented features and performance, not only innovative for prostate radiotracer imaging but possibly also for other organs.

Research paper thumbnail of An imaging technique for detection and absolute calibration of scintillation light

The Review of Scientific Instruments, Mar 1, 2010

Triggered by the need of a detection system to be used in experiments of nuclear fusion in laser-... more Triggered by the need of a detection system to be used in experiments of nuclear fusion in laser-generated plasmas, we developed an imaging technique for the measurement and calibration of the scintillation light yield of scintillating materials. As in such experiments, all the reaction products are generated in an ultrashort time frame, the event-by-event data acquisition scheme is not feasible. As an alternative to the emulsion technique (or the equivalent CR39 sheets) we propose a scintillating screen readout by means of a high performance charge coupled device camera. Even though it is not strictly required in the particular application, this technique allows the absolute calibration of the scintillation light yield.

Research paper thumbnail of Beam imaging in the injection line of the INFN-LNS superconducting cyclotron

Review of Scientific Instruments, 2016

A cheap and efficient diagnostic system for beam monitoring has been recently developed at INFN-L... more A cheap and efficient diagnostic system for beam monitoring has been recently developed at INFN-LNS in Catania. It consists of a high sensitivity CCD camera detecting the light produced by an ion beam hitting the surface of a scintillating screen and a frame grabber for image acquisition. A scintillating screen, developed at INFN-LNS and consisting of a 2 μm BaF2 layer evaporated on an aluminium plate, has been tested by using (20)Ne and (40)Ar beams in the keV energy range. The CAESAR ECR ion source has been used for investigating the influence of the frequency and magnetic field tuning effects, the impact of the microwave injected power, and of the focusing solenoids along the low energy beam transport on the beam shape and current. These tests will allow to better understand the interplay between the plasma and beam dynamics and, moreover, to improve the transport efficiency along the low energy beam line and the matching with the superconducting cyclotron, particularly relevant in view of the expected upgrade of the machine.