On the synergy of nuclear data for fusion and model assumptions

A deuteron breakup (BU) parametrization is involved within the BU analysis of recently measured reaction-in-flight (RIF) neutron time-of-flight spectrum, while open questions underlined previously on related fast-neutron induced reaction on Zr isotopes are also addressed in a consistent way, at once with the use of a recent optical potential for α-particles to understand the large discrepancy between the measured and calculated cross sections of the 94Zr(n,α)91Sr reaction. Thus the synergy between the above-mentioned three distinct subjects may finally lead to smaller uncertainties of the nuclear data for fusion while the RIF neutron spectra may also be used to support nuclear model assumptions

Nuclear data for fusion technology – the European approach

The European approach for the development of nuclear data for fusion technology applications is presented. Related R&D activities are conducted by the Consortium on Nuclear Data Development and Analysis for Fusion to satisfy the nuclear data needs of the major projects including ITER, the Early Neutron Source (ENS) and DEMO. Recent achievements are presented in the area of nuclear data evaluations, benchmarking and validation, nuclear model improvements, and uncertainty assessments

The Soreq Applied Research Accelerator Facility (SARAF) - Overview, Research Programs and Future Plans

The Soreq Applied Research Accelerator Facility (SARAF) is under construction in the Soreq Nuclear Research Center at Yavne, Israel. When completed at the beginning of the next decade, SARAF will be a user facility for basic and applied nuclear physics, based on a 40 MeV, 5 mA CW proton/deuteron superconducting linear accelerator. Phase I of SARAF (SARAF-I, 4 MeV, 2 mA CW protons, 5 MeV 1 mA CW deuterons) is already in operation, generating scientific results in several fields of interest. The main ongoing program at SARAF-I is the production of 30 keV neutrons and measurement of Maxwellian Averaged Cross Sections (MACS), important for the astrophysical s-process. The world leading Maxwellian epithermal neutron yield at SARAF-I ($5\times 10^{10}$ epithermal neutrons/sec), generated by a novel Liquid-Lithium Target (LiLiT), enables improved precision of known MACSs, and new measurements of low-abundance and radioactive isotopes. Research plans for SARAF-II span several disciplines: Precision studies of beyond-Standard-Model effects by trapping light exotic radioisotopes, such as $^6$He, $^8$Li and $^{18,19,23}$Ne, in unprecedented amounts (including meaningful studies already at SARAF-I); extended nuclear astrophysics research with higher energy neutrons, including generation and studies of exotic neutron-rich isotopes relevant to the rapid (r-) process; nuclear structure of exotic isotopes; high energy neutron cross sections for basic nuclear physics and material science research, including neutron induced radiation damage; neutron based imaging and therapy; and novel radiopharmaceuticals development and production. In this paper we present a technical overview of SARAF-I and II, including a description of the accelerator and its irradiation targets; a survey of existing research programs at SARAF-I; and the research potential at the completed facility (SARAF-II).Comment: 32 pages, 31 figures, 10 tables, submitted as an invited review to European Physics Journal

The dark side of alpha-particle optical potential: Emission from excited nuclei

Further analysis of α-particle emission from similar nuclei excited in neutron- as well as low-energy proton-induced reactions is involved concerning a possible difference between the optical model potentials (OMPs) which describe either alpha-particle elastic scattering and induced reactions or alpha-emission from excited compound nuclei. The key role of the pickup direct interaction is finally proved even at incident energies below ~10 MeV, as well as being eventually at the origin of the above-mentioned OMPs difference

On the synergy of nuclear data for fusion and model assumptions

A deuteron breakup (BU) parametrization is involved within the BU analysis of recently measured reaction-in-flight (RIF) neutron time-of-flight spectrum, while open questions underlined previously on related fast-neutron induced reaction on Zr isotopes are also addressed in a consistent way, at once with the use of a recent optical potential for α-particles to understand the large discrepancy between the measured and calculated cross sections of the 94Zr(n,α)91Sr reaction. Thus the synergy between the above-mentioned three distinct subjects may finally lead to smaller uncertainties of the nuclear data for fusion while the RIF neutron spectra may also be used to support nuclear model assumptions

Role of direct interactions in (

Accurate cross sections of deuteron–induced reactions within an enlarged energy range up to 50 MeV are definitely involved by demands of on-going strategic research programs (ITER, IFMIF, SPIRAL2-NFS) using deuteron beams. Among them, the (d, p) and (d, 2p) reaction cross sections leading to hydrogen– gas bubble accumulation in the structural materials are very important for radiation damage studies. In contrast to the case of neutrons, systematics of deuteron activation cross sections, including those leading to hydrogen, triton, and helium–gas accumulation, is modest while even the newest evaluations show apparent discrepancies. Thus, the present work is devoted to the comparative analysis of measurements, model calculations, and evaluation corresponding to (d, p), and (d, 2p) activation cross sections, to improve the description of existing data and to provide trustful predictions where no measured data exist

Additional reaction mechanisms to statistical α-emission and the related optical-potential validation

The major role of consistent parameter sets within analysis of neutron-induced α-particle emission, for the assessment of a possible difference between the optical model potentials (OMPs), which describe either alpha-particle elastic scattering and induced reactions or alpha-emission from excited compound nuclei, is shown. They are involved at variance with use of either empirical rescaling factors of the γ and/or neutron widths or even combinations of all options of a computer code for main input parameters. Suitable description of all competitive reaction channels, confirmed by a careful uncertainty analysis in order to avoid parameter ambiguities and/or error compensation, supports further consideration of additional direct processes

Role of the direct processes in low-energy deuteron interactions

An extended analysis of the key role of direct interactions, i.e., breakup, stripping and pick-up processes, has been carried out for deuteron-induced reactions. Particular comments concern the deuteron breakup which is the dominant mechanism involved in surrogate reactions on heavy nuclei, around the Coulomb barrier

Analysis of empirical parametrization and microscopical studies of deuteron-induced reactions

A review of deuteron-induced reaction analyses is carried out paying due consideration to reaction cross-section parametrization as well as theoretical models associated to the deuteron interaction process. The key role of direct interactions, i.e., breakup, stripping and pick-up processes is stressed out by the comparison of data with theoretical and evaluation predictions, including the latest TENDL-2017 library