Giovanni Ricco - Academia.edu (original) (raw)

Papers by Giovanni Ricco

2013 3rd International Conference on Advancements in Nuclear Instrumentation, Measurement Methods and their Applications (ANIMMA), 2013

A low-power prototype of neutron amplifier, based on a 70 MeV, high current proton cyclotron bein... more A low-power prototype of neutron amplifier, based on a 70 MeV, high current proton cyclotron being installed at LNL for the SPES RIB facility, was recently proposed within INFN-E project. This prototype uses a thick Beryllium converter to produce a fast neutron spectrum feeding a sub-critical reactor core. To complete the design of such facility the new measurement of neutron yield from a thick Beryllium target was performed at LNS. This measurement used liquid scintillator detectors to identify produced neutrons by Pulse Shape Discrimination and Time of Flight technique to measure neutron energy in the range 0.5-62 MeV. To extend the covered neutron energy range 3 He detector was used to measure neutrons below 0.5 MeV. The obtained yields were normalized to the charge deposited by the proton beam on the metallic Beryllium target. These techniques allowed to achieve a wide angular coverage from 0 to 150 degrees and to explore almost complete neutron energy interval.

EPJ Web of Conferences, 2014

Within European Partitioning & Transmutation research programs, infrastructures specifically dedi... more Within European Partitioning & Transmutation research programs, infrastructures specifically dedicated to the study of fundamental reactor physics and engineering parameters of future fast-neutron-based reactors are very important, being some of these features not available in present zero-power prototypes. This presentation will

Problems of Atomic Science and Technology, Ser. Thermonuclear Fusion, 2021

Fusion-fission hybrid systems (FFH) represent a coupling between a fusion device and a subcritica... more Fusion-fission hybrid systems (FFH) represent a coupling between a fusion device and a subcritical fission reactor driven by neutrons produced by fusion reactions. This kind of systems, in principle, can be useful for different purposes, for example, as energy amplifier or as nuclear waste burner. In this work, the preliminary characteristics and potentialities of a FFH based on a tokamak device characterized by high magnetic field (B > 9 T) and high-density plasma (n > 10 14 cm-3) have been evaluated. During the years high magnetic field compact tokamaks have been designed, built and operated. Thanks to their characteristics, such as compactness, high field and high density plasma, these devices can produce intense neutron fluxes, and therefore are good candidates to be incorporated in FFH while operating in a sub-ignited regime. An additional advantage is that their design is based on relatively simple existing technology. In this work, a coupling between a tokamak (operating in DD-mode) and a subcritical molten salt fission blanket has been proposed. Molten salt reactor could be adapted for this purpose and could help the hybrid system to increase its energy balance. A model with a molten salt fission blanket (k eff = 0.92, P = 95 MW) instead of the lithium one, has been considered and studied in terms of neutronic evaluations. Presented preliminary numerical calculations based on a neutron Monte-Carlo code confirm the potentialities of the system.

EPJ Web of Conferences, 2017

The neutron multiplication factor k e f f is a key quantity to characterize subcritical neutron m... more The neutron multiplication factor k e f f is a key quantity to characterize subcritical neutron multiplying devices and for understanting their physical behaviour, being related to the fundamental eigenvalue of Boltzmann transport equation. Both the maximum available power-and all quantities related to it, like, e.g. the effectiveness in burning nuclear wastes-as well as reactor kinetics and dynamics depend on k e f f. Nevertheless, k e f f is not directly measurable and its determination results from the solution of an inverse problem: minimizing model dependence of the solution for k e f f then becomes a critical issue, relevant both for practical and theoretical reasons.

Journal of Physics: Conference Series, 2013

The European Physical Journal Plus, 2014

In this paper the current status of the study of the dynamical behaviour of the proposed ADS is p... more In this paper the current status of the study of the dynamical behaviour of the proposed ADS is presented; it is a complex multi-physics problem which, in the present case of a very low k eff system, is conveniently analyzed because the characteristic time scales of the problem are well separated. To be more specific, time scales of the neutronic (prompt) response of the system are so short to be negligible when studying thermal, mechanical and hydraulic aspects.

EPJ Web of Conferences, 2014

Within European Partitioning & Transmutation research programs, infrastructures specifically dedi... more Within European Partitioning & Transmutation research programs, infrastructures specifically dedicated to the study of fundamental reactor physics and engineering parameters of future fast-neutron-based reactors are very important, being some of these features not available in present zero-power prototypes. This presentation will a Corresponding

EPJ Web of Conferences, 2017

In this work we report initial studies on a low power Accelerator-Driven System as a possible exp... more In this work we report initial studies on a low power Accelerator-Driven System as a possible experimental facility for the measurement of relevant integral nuclear quantities. In particular, we performed Monte Carlo simulations of minor actinides and fission products irradiation and estimated the fission rate within fission chambers in the reactor core and the reflector, in order to evaluate the transmutation rates and the measurement sensitivity. We also performed a photo-peak analysis of available experimental data from a research reactor, in order to estimate the expected sensitivity of this analysis method on the irradiation of samples in the ADS considered.

Physical review letters, Jan 25, 2002

Models of baryon structure predict a small quadrupole deformation of the nucleon due to residual ... more Models of baryon structure predict a small quadrupole deformation of the nucleon due to residual tensor forces between quarks or distortions from the pion cloud. Sensitivity to quark versus pion degrees of freedom occurs through the Q2 dependence of the magnetic (M1+), electric (E1+), and scalar (S1+) multipoles in the gamma*p-->Delta(+)-->p pi(0) transition. We report new experimental values for the ratios E(1+)/M(1+) and S(1+)/M(1+) over the range Q2 = 0.4-1.8 GeV2, extracted from precision p(e,e(')p)pi(0) data using a truncated multipole expansion. Results are best described by recent unitary models in which the pion cloud plays a dominant role.

Two-proton correlations at small relative momentum q were studied in the eA(3He,4He,C,Fe)→e'p... more Two-proton correlations at small relative momentum q were studied in the eA(3He,4He,C,Fe)→e'ppX reaction at E0=4.46 GeV using the CLAS detector at Jefferson Lab. The enhancement of the correlation function at small q was found to be in accordance with theoretical expectations. Sizes of the emission region were extracted, and proved to be dependent on A and on the proton momentum. The size of the two-proton emission region for He was measured in eA reactions for the first time.

The exclusive reaction γp → pπ + π − was studied in the photon energy range 3.0 -3.8 GeV and mome... more The exclusive reaction γp → pπ + π − was studied in the photon energy range 3.0 -3.8 GeV and momentum transfer range 0.4 < −t < 1.0 GeV 2 . Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility. In this kinematic range the integrated luminosity was about 20 pb −1 . The reaction was isolated by detecting the π + and proton in CLAS, and reconstructing the π − via the missing-mass technique. Moments of the di-pion decay angular distributions were derived from the experimental data. Differential cross sections for the S, P , and D-waves in the M π + π − mass range 0.4 − 1.4 GeV were derived performing a partial wave expansion of the extracted moments. Besides the dominant contribution of the ρ(770) meson in the P -wave, evidence for the f0(980) and the f2(1270) mesons was found in the S and D-waves, respectively. The differential production cross sections dσ/dt for individual waves in the mass range of the above-mentioned mesons were extracted. This is the first time the f0(980) has been measured in a photoproduction experiment.

Physical Review Letters, 2001

Physical Review Letters, 2005

We investigate the transition from the nucleon-meson to quark-gluon description of the strong int... more We investigate the transition from the nucleon-meson to quark-gluon description of the strong interaction using the photon energy dependence of the d(γ, p)n differential cross section for photon energies above 0.5 GeV and center-of-mass proton angles between 30 • and 150 • . A possible signature for this transition is the onset of cross section s −11 scaling with the total energy squared, s, at some proton transverse momentum, PT . The results show that the scaling has been reached for proton transverse momentum above about 1.1 GeV/c. This may indicate that the quark-gluon regime is reached above this momentum. PACS numbers: 24.85.+p, 21.45.+v

2013 3rd International Conference on Advancements in Nuclear Instrumentation, Measurement Methods and their Applications (ANIMMA), 2013

A low-power prototype of neutron amplifier, based on a 70 MeV, high current proton cyclotron bein... more A low-power prototype of neutron amplifier, based on a 70 MeV, high current proton cyclotron being installed at LNL for the SPES RIB facility, was recently proposed within INFN-E project. This prototype uses a thick Beryllium converter to produce a fast neutron spectrum feeding a sub-critical reactor core. To complete the design of such facility the new measurement of neutron yield from a thick Beryllium target was performed at LNS. This measurement used liquid scintillator detectors to identify produced neutrons by Pulse Shape Discrimination and Time of Flight technique to measure neutron energy in the range 0.5-62 MeV. To extend the covered neutron energy range 3 He detector was used to measure neutrons below 0.5 MeV. The obtained yields were normalized to the charge deposited by the proton beam on the metallic Beryllium target. These techniques allowed to achieve a wide angular coverage from 0 to 150 degrees and to explore almost complete neutron energy interval.

EPJ Web of Conferences, 2014

Within European Partitioning & Transmutation research programs, infrastructures specifically dedi... more Within European Partitioning & Transmutation research programs, infrastructures specifically dedicated to the study of fundamental reactor physics and engineering parameters of future fast-neutron-based reactors are very important, being some of these features not available in present zero-power prototypes. This presentation will

Problems of Atomic Science and Technology, Ser. Thermonuclear Fusion, 2021

Fusion-fission hybrid systems (FFH) represent a coupling between a fusion device and a subcritica... more Fusion-fission hybrid systems (FFH) represent a coupling between a fusion device and a subcritical fission reactor driven by neutrons produced by fusion reactions. This kind of systems, in principle, can be useful for different purposes, for example, as energy amplifier or as nuclear waste burner. In this work, the preliminary characteristics and potentialities of a FFH based on a tokamak device characterized by high magnetic field (B > 9 T) and high-density plasma (n > 10 14 cm-3) have been evaluated. During the years high magnetic field compact tokamaks have been designed, built and operated. Thanks to their characteristics, such as compactness, high field and high density plasma, these devices can produce intense neutron fluxes, and therefore are good candidates to be incorporated in FFH while operating in a sub-ignited regime. An additional advantage is that their design is based on relatively simple existing technology. In this work, a coupling between a tokamak (operating in DD-mode) and a subcritical molten salt fission blanket has been proposed. Molten salt reactor could be adapted for this purpose and could help the hybrid system to increase its energy balance. A model with a molten salt fission blanket (k eff = 0.92, P = 95 MW) instead of the lithium one, has been considered and studied in terms of neutronic evaluations. Presented preliminary numerical calculations based on a neutron Monte-Carlo code confirm the potentialities of the system.

EPJ Web of Conferences, 2017

The neutron multiplication factor k e f f is a key quantity to characterize subcritical neutron m... more The neutron multiplication factor k e f f is a key quantity to characterize subcritical neutron multiplying devices and for understanting their physical behaviour, being related to the fundamental eigenvalue of Boltzmann transport equation. Both the maximum available power-and all quantities related to it, like, e.g. the effectiveness in burning nuclear wastes-as well as reactor kinetics and dynamics depend on k e f f. Nevertheless, k e f f is not directly measurable and its determination results from the solution of an inverse problem: minimizing model dependence of the solution for k e f f then becomes a critical issue, relevant both for practical and theoretical reasons.

Journal of Physics: Conference Series, 2013

The European Physical Journal Plus, 2014

In this paper the current status of the study of the dynamical behaviour of the proposed ADS is p... more In this paper the current status of the study of the dynamical behaviour of the proposed ADS is presented; it is a complex multi-physics problem which, in the present case of a very low k eff system, is conveniently analyzed because the characteristic time scales of the problem are well separated. To be more specific, time scales of the neutronic (prompt) response of the system are so short to be negligible when studying thermal, mechanical and hydraulic aspects.

EPJ Web of Conferences, 2014

Within European Partitioning & Transmutation research programs, infrastructures specifically dedi... more Within European Partitioning & Transmutation research programs, infrastructures specifically dedicated to the study of fundamental reactor physics and engineering parameters of future fast-neutron-based reactors are very important, being some of these features not available in present zero-power prototypes. This presentation will a Corresponding

EPJ Web of Conferences, 2017

In this work we report initial studies on a low power Accelerator-Driven System as a possible exp... more In this work we report initial studies on a low power Accelerator-Driven System as a possible experimental facility for the measurement of relevant integral nuclear quantities. In particular, we performed Monte Carlo simulations of minor actinides and fission products irradiation and estimated the fission rate within fission chambers in the reactor core and the reflector, in order to evaluate the transmutation rates and the measurement sensitivity. We also performed a photo-peak analysis of available experimental data from a research reactor, in order to estimate the expected sensitivity of this analysis method on the irradiation of samples in the ADS considered.

Physical review letters, Jan 25, 2002

Models of baryon structure predict a small quadrupole deformation of the nucleon due to residual ... more Models of baryon structure predict a small quadrupole deformation of the nucleon due to residual tensor forces between quarks or distortions from the pion cloud. Sensitivity to quark versus pion degrees of freedom occurs through the Q2 dependence of the magnetic (M1+), electric (E1+), and scalar (S1+) multipoles in the gamma*p-->Delta(+)-->p pi(0) transition. We report new experimental values for the ratios E(1+)/M(1+) and S(1+)/M(1+) over the range Q2 = 0.4-1.8 GeV2, extracted from precision p(e,e(')p)pi(0) data using a truncated multipole expansion. Results are best described by recent unitary models in which the pion cloud plays a dominant role.

Two-proton correlations at small relative momentum q were studied in the eA(3He,4He,C,Fe)→e'p... more Two-proton correlations at small relative momentum q were studied in the eA(3He,4He,C,Fe)→e'ppX reaction at E0=4.46 GeV using the CLAS detector at Jefferson Lab. The enhancement of the correlation function at small q was found to be in accordance with theoretical expectations. Sizes of the emission region were extracted, and proved to be dependent on A and on the proton momentum. The size of the two-proton emission region for He was measured in eA reactions for the first time.

The exclusive reaction γp → pπ + π − was studied in the photon energy range 3.0 -3.8 GeV and mome... more The exclusive reaction γp → pπ + π − was studied in the photon energy range 3.0 -3.8 GeV and momentum transfer range 0.4 < −t < 1.0 GeV 2 . Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility. In this kinematic range the integrated luminosity was about 20 pb −1 . The reaction was isolated by detecting the π + and proton in CLAS, and reconstructing the π − via the missing-mass technique. Moments of the di-pion decay angular distributions were derived from the experimental data. Differential cross sections for the S, P , and D-waves in the M π + π − mass range 0.4 − 1.4 GeV were derived performing a partial wave expansion of the extracted moments. Besides the dominant contribution of the ρ(770) meson in the P -wave, evidence for the f0(980) and the f2(1270) mesons was found in the S and D-waves, respectively. The differential production cross sections dσ/dt for individual waves in the mass range of the above-mentioned mesons were extracted. This is the first time the f0(980) has been measured in a photoproduction experiment.

Physical Review Letters, 2001

Physical Review Letters, 2005

We investigate the transition from the nucleon-meson to quark-gluon description of the strong int... more We investigate the transition from the nucleon-meson to quark-gluon description of the strong interaction using the photon energy dependence of the d(γ, p)n differential cross section for photon energies above 0.5 GeV and center-of-mass proton angles between 30 • and 150 • . A possible signature for this transition is the onset of cross section s −11 scaling with the total energy squared, s, at some proton transverse momentum, PT . The results show that the scaling has been reached for proton transverse momentum above about 1.1 GeV/c. This may indicate that the quark-gluon regime is reached above this momentum. PACS numbers: 24.85.+p, 21.45.+v