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The assessment of an $$\alpha $$ α -particle optical model potential for nucleon–induced $$\alpha $$ α -emission within the $$A$$ A $$\sim $$ ∼ 60 mass-number range [Avrigeanu and Avrigeanu (Eur. Phys. J. A 57:54, 2021)] is completed by analysis of neutron–induced reactions on stable Ni isotopes. The same consistent set of nuclear–model input parameters as well as first uncertainty analysis of calculated cross sections related to the accuracy of independent data formerly used within parameter setting up have been concerned. Description of absorption and emission of $$\alpha $$ α -particles by the same potential is validated, while the pickup direct reaction and Giant Quadrupole Resonance (GQR) $$\alpha $$ α -emission beyond the statistical predictions are confirmed by recent data around the GQR energies.

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.

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.

Background: The deuteron weak binding energy is responsible for high complexity of the deuteron interaction with nuclei that involves also a variety of reactions initiated by the nucleons following the deuteron breakup (BU). An update of both the scarce experimental deuteron database and the incomplete theoretical frame of the deuteron activation analysis is thus needed. Removal of discrepancies between experimental data, and a consistent inclusion of BU as well as of stripping and pickup direct reactions (DR) contributions within deuteron activation analysis, besides preequilibrium emission (PE) and fully equilibrated compound nucleus (CN) decay, are essential, too.Purpose: Accurate new measurements of low-energy deuteron-induced reaction cross sections for natural Zr target are intended to enhance the related database and the opportunity for a unitary and consistent account of BU, DR, PE, and CN involved reaction mechanisms.Methods: The activation cross sections of $^{90,91m,92m,94m,95m,95g,96,97}\mathrm{Nb}$, $^{89m,89,95,97}\mathrm{Zr}$, and $^{87m,87g,87,88,90m,91m,94}\mathrm{Y}$ nuclei in deuteron-induced reactions on Zr at energies up to 20 MeV were measured by the stacked-foil technique and high-resolution $\ensuremath{\gamma}$ spectrometry using the U-120M cyclotron of the Center of Accelerators and Nuclear Analytical Methods (CANAM) infrastructure of the Nuclear Physics Institute of the Czech Academy of Sciences (NPI CAS). Their extended analysis, together with all available data for deuteron interactions with Zr isotopes up to 60 MeV, has included every process from elastic scattering until CN evaporation, with particular attention paid to BU and DR mechanisms.Results: Newly measured activation excitation functions proved essential for the deuteron database, while analysis of all available data strengthens their consistent account provided that (i) suitable BU and DR assessment is completed by (ii) PE and CN contributions corrected for total-reaction cross-section decrease due to the leakage of the initial deuteron flux towards BU and DR processes.Conclusions: The suitable description of nuclear mechanisms involved within deuteron-induced reactions on Zr, especially the BU and DR processes, is validated by overall agreement of the calculated and measured cross sections including the new experimental data at low energies.

The scarce data systematics and complexity of deuteron interactions demand the update of both the experimental database and theoretical frame of deuteron activation cross sections. Various reactions induced by neutrons and protons following the deuteron breakup (BU) should be also taken into account. On the other hand, deuteron reaction cross sections recommended recently for high-priority elements are still based on data fit without predictive power. Purpose: Accurate new measurements of low-energy deuteron-induced reaction cross sections for monoisotopic (55Mn) natural manganese target enhance the related database as well as the opportunity of an unitary and consistent account of the related reaction mechanisms. Method: Activation cross sections of 54,56Mn, and 51Cr nuclei by deuterons on $^{55}$Mn were measured at energies, 11 pages, 7 figures. arXiv admin note: text overlap with arXiv:1809.02706

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.

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.

The role of nuclear data for neutronics analyses of Fusion Technology (FT) facilities is presented in this paper. Nuclear data evaluations of high quality are required for transport simulations, uncertainty assessments, activation and radiation damage calculations affecting the design and performance of the FT facilities, as well as safety, licensing, waste management and decommissioning issues. A corresponding programme on the nuclear data development (NDD) and qualification is conducted within the Power Plant Physics and Technology (PPPT) programme of EUROfusion supporting the development of the DEMO fusion power plant and the IFMIF-DONES neutron source. The programme builds on the achievements of pre-ceding NDD activities within the European fusion programme as addressed in the paper. Further needs for design, shielding, activation and radiation dose calculations are discussed, and recommendations are given to further improve and qualify the nuclear data base for PPPT nuclear analyses. This includes dedicated experimental activities tailored to the needs of DEMO and IFMIF-DONES.

International audience; The proton, deuteron and alpha induced reactions are of a great interest for the assessment of induced radioactivity of accelerator components, targets and beam stoppers as well as isotope production for medicine and also to nuclear astrophysics. We present a new irradiation chamber for activation measurements, that forms a prolongation of long-term experimental activities using stacked-foil activation technique in NPI CAS, Řež. The chamber is based on an airlock system and is coupled to a pneumatic transfer system delivered by KIT Karlsruhe. This system is installed in GANIL/SPIRAL2-NFS and will be used for proton, deuteron and alpha particle activation measurements with long- and short-lived isotopes.

The activities of the EUROfusion consortiums on the development of high quality nuclear data for fusion applications are presented. The activities, implemented in the Power Plant Physics and Technology (PPPT) programme of EUROfusion, include nuclear data evaluations for neutron and deuteron induced reactions and the production of related data libraries which satisfy the needs for nuclear analyses of the DEMO fusion power plant and the IFMIF-DONES neutron source. The activities are closely linked to the JEFF initiative of the NEA Data Bank. The evaluation work is complemented by extensive benchmark, sensitivity and uncertainty analyses to check the performance of the evaluated cross-section data and libraries against integral experiments.

Purpose: Accurate new measurements of low-energy deuteron-induced reaction cross sections for natural Cr target can enhance the related database and the opportunity for an unitary and consistent account of the involved reaction mechanisms. Methods: The activation cross sections of $^{51,52,54}$Mn, $^{51}$Cr, and $^{48}$V nuclei for deuterons incident on natural Cr at energies up to 20 MeV, were measured by the stacked-foil technique and high resolution gamma spectrometry using U-120M cyclotron of the Center of Accelerators and Nuclear Analytical Methods (CANAM) of the Nuclear Physics Institute of the Czech Academy of Sciences (NPI CAS). They as well as formerly available data for deuteron interactions with Cr isotopes up to 60 MeV are the object of an extended analysis of all processes from elastic scattering until the evaporation from fully equilibrated compound system, but with a particular attention given to the BU and DR mechanisms. Results: The new measured activation excitation functions proved essential for the enrichment of the deuteron database, while the theoretical analysis of all available data strengthens for the first time their consistent account provided that (i) a suitable BU and DR assessment is completed by (ii) the assumption of PE and CN contributions corrected for decrease of the total-reaction cross section due to the leakage of the initial deuteron flux towards BU and DR processes. Conclusions: The suitable description of nuclear mechanisms involved within deuteron-induced reactions on chromium, taking into account especially the BU and DR direct processes, is validated by an overall agreement of the calculated and measured cross sections including particularly the new experimental data at low energies., Comment: 15 pages, 14 figures, accepted for publication in Phys. Rev. C

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., Comment: 5 pages, 3 figures. Contribution at Int. Conf. on Nucl. Data for Science and Technology (ND2016), 11-16.09.2016, Bruges, Belgium

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.

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 94 Zr( n ,α) 91 Sr 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.

This paper presents an overview of the activities of the European Consortium on Nuclear Data Development and Analysis for Fusion. The Consortium combines available European expertise to provide services for the generation, maintenance, and validation of nuclear data evaluations and data files relevant for ITER, IFMIF and DEMO, as well as codes and software tools required for related nuclear calculations.

A complete analysis of the nuclear reaction mechanisms involved within nat Fe( d , x ) 55 Co reaction, i.e. the breakup, stripping, pick-up, pre-equilibrium emission, and evaporation from fully equilibrated compound nucleus, is presented in order to highlight the importance of direct mechanisms that are not appropriately considered in the evaluation procedure. The overall agreement between the measured data and model calculations confirms the correctness of nuclear mechanism description taken into account stressing out the omissions of the evaluation procedures.

The accurate measurement of neutron capture cross sections of all Fe and Ni isotopes is important for disentangling the contribution of the s-process and the r-process to the stellar nucleosynthesis of elements in the mass range 60 < A < 120. At the same time. Fe and Ni are important components of structural materials and improved neutron cross section data is relevant in the design of new nuclear systems. With the aim of obtaining improved capture data on all stable iron and nickel isotopes, a program of measurements has been launched at the CERN Neutron Time of Flight Facility n_TOF.

After a halt of four years, the n_TOF spallation neutron facility at CERN has resumed operation in November 2008 with a new spallation target characterized by an improved safety and engineering design, resulting in a more robust overall performance and efficient cooling. The first measurement during the 2009 run has aimed at the full characterization of the neutron beam. Several detectors, such as calibrated fission chambers, the n\textunderscore TOF Silicon Monitor, a MicroMegas detector with 10B and 235U samples, as well as liquid and solid scintillators have been used in order to characterize the properties of the neutron fluence. The spatial profile of the beam has been studied with a specially designed "X-Y" MicroMegas which provided a 2D image of the beam as a function of neutron energy. Both properties have been compared with simulations performed with the FLUKA code. The characterization of the resolution function is based on results from simulations which have been verified by the study of narrow capture resonances of 56Fe, which were measured as part of a new campaign of (n, γ) measurements on Fe and Ni isotopes.

An extended analysis has been performed of elastic-scattering and reaction cross-sections of deuterons on the Al 27 nucleus, for deuteron energies from 3 to 60 MeV, based on a semi-microscopic optical potential with a double-folding real part and phenomenological imaginary and spin-orbit terms. An increased effort is devoted to the breakup mechanism, the analysis of proton-emission spectra and angular distributions from deuteron-induced reactions on nuclei from Al to Pb, at incident energies from 15 to 80 MeV, providing the energy- and mass-dependence of the breakup mechanism contribution. The corresponding direct-reaction cross-sections within the same energy range has then been analyzed, the improved description of both the elastic-scattering and reaction measured data backing the proper use of these optical potentials for deuteron activation assessment.

Excitation functions were measured for the $^{55}$Mn(n,2n)$^{54}$Mn, $^{55}$Mn(n,$\alpha$)$^{52}$V, $^{63}$Cu(n,$\alpha$)$^{60}$Co, $^{65}$Cu(n,2n)$^{64}$Cu, and $^{65}$Cu(n,p)$^{65}$Ni reactions from 13.47 to 14.83 MeV. The experimental cross sections are compared with the results of calculations including all activation channels for the stable isotopes of Mn and Cu, for neutron incident energies up to 50 MeV. Within the energy range up to 20 MeV the model calculations are most sensitive to the parameters related to nuclei in the early stages of the reaction, while the model assumptions are better established by analysis of the data in the energy range 20-40 MeV. While the present analysis has taken advantage of both a new set of accurate measured cross sections around 14 MeV and the larger data basis fortunately available between 20 and 40 MeV for the Mn and Cu isotopes, the need of additional measurements below as well as above 40 MeV is pointed out. Keywords: 55Mn, 63,65Cu, E$\leq$40 MeV, Neutron activation cross section measurements, Nuclear reactions, Model calculations, Manganese, Copper, Comment: 39 pages, 12 figures

Background: Recent studies of deuteron-induced reactions around the Coulomb barrier $B$ pointed out that numerical calculations for deuteron-induced reactions are beyond current capabilities. The statistical model of nuclear reactions was used in this respect since the compound-nucleus (CN) mechanism was considered to be responsible for most of the total-reaction cross section ${\ensuremath{\sigma}}_{R}$ in this energy range. However, specific noncompound processes such as the breakup (BU) and direct reactions (DR) should be also considered for the deuteron-induced reactions, making them different from reactions with other incident particles.Purpose: The unitary and consistent BU and DR consideration in deuteron-induced reactions is proved to yield results at variance with the assumption of negligible noncompound components.Method: The CN fractions of ${\ensuremath{\sigma}}_{R}$ obtained by analysis of measured neutron angular distributions in deuteron-induced reactions on $^{27}\mathrm{Al}$, $^{56}\mathrm{Fe}$, $^{63,65}\mathrm{Cu}$, and $^{89}\mathrm{Y}$ target nuclei, around $B$, are compared with the results of an unitary analysis of every reaction mechanism. The latter values have been supported by the previously established agreement with all available deuteron data for $^{27}\mathrm{Al}$, $^{54,56\ensuremath{-}58,\mathrm{nat}}\mathrm{Fe}$, $^{63,65,\mathrm{nat}}\mathrm{Cu}$, and $^{93}\mathrm{Nb}$.Results: There is a significant difference between the larger CN contributions obtained from measured neutron angular distributions and calculated results of an unitary analysis of every deuteron-interaction mechanism. The decrease of the latter values is mainly due to the BU component.Conclusions: The above-mentioned differences underline the key role of the breakup and direct reactions that should be considered explicitly in the case of deuteron-induced reactions.

Within the double folding formalism of the α -nucleus optical potential, used previously for a semi-microscopic analysis of the α -particle elastic scattering on A ∼ 100 nuclei at energies below 32 MeV, effects due to changes of the nuclear density at a finite temperature are considered. Parameterizations of the double-folding (DF) real potential as well as of a regional phenomenological potential have been used in the study of the ( n , α ) reaction cross sections for the target nuclei 92,95,98,100 Mo. Taking into account the microscopic DF potentials based on nuclear density distributions, we are able to fully describe the excitation functions of the ( n , α ) reactions. It is shown that the temperature dependence of the nuclear density distribution function can be an important aspect that has to be included in statistical model calculations even for a nuclear temperature smaller than 2 MeV.

An analysis of the elastic scattering of deuterons on 6,7Li, for energies up to 50 MeV, has been carried out by using a phenomenological optical potential. Energy-dependent average parameters of the optical model potential have been obtained in the analysis of the corresponding real and imaginary volume integrals, pointing out an “anomalous” behavior of the real potential when the imaginary part approaches zero. This could be a consequence of the dispersion relations, but may be also related to the non-locality of the basic real potential term which introduces a slow and smooth energy dependence. On the other hand, the coupled reaction channels method has been used in order to describe the Li 6 ( d , d 0 ) Li 6 experimental angular distributions including the backward hemisphere at 14.7 and 19.6 MeV but not at 50 MeV. The comparison between the experimental and calculated elastic scattering angular distributions proves the reliability of the present average optical potentials, at variance with the extrapolation of the deuteron global potentials to other mass and energy domains.

Results of new cross section measurements are presented for the following neutron-induced reactions: 58Ni(n, p) 58 m + g Co , 58Ni(n, p)58mCo, 58Ni(n, x)57Co, 58Ni(n, 2n)57Ni, 60Ni(n, p) 60 m + g Co , 60Ni(n, p)60mCo, 61Ni(n, p)61Co, 61Ni(n, x)60mCo, 62Ni(n, x)61Co, and 59Co(n, 2n) 58 m + g Co with emphasis on incident energies between 14 and 20 MeV. In addition, new results have been obtained for the isomer ratios of the 58Ni(n, p) 58 m + g Co , the 60Ni(n, p) 60 m + g Co and 59Co(n, 2n) 58 m + g Co reactions. Detailed model calculations were undertaken to study the systematics of (n,xp) reactions on Ni isotopes and the use of the measured isomer ratios for the determination of the effective moment of inertia in the level density expression. Good overall agreement was obtained and, in particular, the case of the 58Ni target isotope now shows a complete physically consistent database that is ideal to test model calculations. The difference in spin between isomer and ground state of ΔJ=3 for the 58Co and 60Co residual nuclei results in a sensitivity to the spin dependence of the level density in these nuclei. However, at present, measurement uncertainties and uncertainties associated with the decay schemes preclude a definitive conclusion about the appropriate value of the effective moment of inertia. A comparison was made between a locally optimized parameter set based on all available data and a global approach. This approach allowed to identify where problems with the global approach can be expected. The locally optimized parameter set includes for the first time gamma-ray strength-functions based on an improved systematics of the gamma-ray widths.

The double-folding formalism of the α -nucleus optical potential is used and appropriate effective nucleon–nucleon ( NN ) interaction and α -particle density distribution at low energies are obtained by analysis of the α – α elastic-scattering at energies below 35 MeV. Next a semi-microscopic analysis based on the Double Folding Model (DFM) for the α -particle elastic scattering on A ∼100 nuclei at energies below 32 MeV has been carried out. The energy-dependent phenomenological imaginary part for this semi-microscopic optical model potential (OMP) was obtained, making use also of the dispersive correction to the microscopic real potential. This imaginary potential has then been introduced within a complete phenomenological analysis of the same data basis. A regional parameter set of the phenomenological OMP for low-energy α -particles has thus been obtained for nuclei in the mass range A ∼100, which is of interest to basic nuclear physics as well as nuclear technology.

The back–shifted Fermi gas (BSFG) model has been used for description of the nuclear level density at excitation energies up to the nucleon binding energy by fitting the latest experimental low–lying discrete levels and average s–wave nucleon resonance spacings D0. The analysis of the ratio of the proton and neutron resonance spacings corresponding to the same compound nucleus has led to the ratio IIr=(0.75±0.06) of the effective moment of inertia of the nucleus to the rigid-body value Ir for the nucleus 51V. The energy-dependent level density parameter and the method proposed by Koning and Chadwick for choosing the appropriate shell correction energy have been adopted for energies above the nucleon binding energy. Finally, a consistent description of all experimental data related to the nuclear level density, i.e. the low–lying discrete levels, the nucleon–resonance data, and the level density data above the nucleon binding energy, has been obtained for nuclei within A–ranges 24–41, 55–70, and 104–114.

Description of the high-energy side of activation excitation functions, most sensitive to pre-equilibrium processes modeling, is reported in this work within the geometry–dependent hybrid (GDH) model. Improved cross-section calculations are reported for fast-neutron induced reactions on 51V and 92, 94–98, 100Mo based on partial level density including surface effects as well as energy–dependent single–particle level densities.

Microscopic elastic-scattering angular distributions have been calculated for 6, 8He on protons at incident energies < 100A MeV by using Tanihata and COSMA models for the density distributions of He nuclei, M3Y-Paris effective NN interaction, and Bray et al. imaginary part of the optical potential. The present microscopic angular distributions based on Tanihata densities are in good agreement with the available experimental data and also similar to results of other theoretical calculations, showing the sensitivity of scattering to the density distributions of these helium isotopes.

Recently cross sections have been measured with the activation technique for selected (n, xn), (n, xp) and (n, xα) reactions on isotopically enriched and natural samples of V, Cr, Co, Ni, Cu, Zn, Se, Zr, Mo, Tc, I, and Pb. Here results are presented for the measured cross sections of the 92Mo(n, p)92mNb, 95Mo(n, p)95mNb, natMo(n, xp)94Nb, 98Mo(n, np) 98mNb, 96Mo(n, np)95mNb, 96Mo(n, p)96Nb, 97Mo(n, p)97mNb, 97Mo(n, p) 97m+9Nb, 97Mo(n, np)96Nb, 98Mo(n, np)97mNb, 98Mo(n, np)97m+9Nb, 92Mo(n, 2n)91mMo, 94Mo(n, 2n)93mMo, 100Mo(n, 2n)99Mo, 92Mo(n, a)89mZr, 100Mo(n, a)97Zr, 208Pb(n, p)208Tl, 206Pb(n, a)203Hg, 206Pb(n, 3n)204mPb, 204Pb(n, n’)204mPb, 204Pb(n, 2n)20SPb, 204Pb(n, 2n)203mPb, 204Pb(n, 3n)202m lPb, 129I(n, 2n)128I, 58Ni(n, np)57Co, reactions and for the isomeric ratio of the 59Co(n, 2n)58m, gCo and S8Ni(n, p)58m, 9Ni reactions. Cross section measurements focussed on the energy range from 16 to 20.5 MeV with few exceptions. Half-lives of the reactions studied vary from 6.3 s to 20300 years. Isotopically...

Cross sections for the reaction natV(n, xα)47Sc were measured from 11.7 to 20.5 MeV with the aim to improve the data base and resolve discrepancies. Simultaneously, new measurements were done for the 51 V(n, α)48Sc reaction, and some additional experimental data were added to those obtained recently for the 51V(n, p)51Ti reaction. Calculations were performed using the STAPRE-H statistical model code with pre-equilibrium contributions that were estimated with a modified geometry dependent hybrid model. A physically consistent description of all pertinent experimental information was attempted. In most cases a description of the experimental data is obtained that is sufficiently accurate to consider adopting the new model calculations in evaluated data files.

The cross section for the nat Mo(n, x ) 94 Nb reaction was measured in the energy range from 14.5 to 20.3 MeV using both conventional γ -rayspectrometry and the ultra low-level γ -ray spectrometry (ULGS) facility in the underground laboratory HADES. The exceptionally long half-life of the activation product 94 Nb of 20300 years required a long irradiation, a large sample and a special irradiation geometry, to allow a simultaneous determination of the three data points. This measurement presents the first data above 14 MeV. The data are well described by model calculations with the STAPRE-H code that include the 94 Mo(n, p) 94 Nb and 95 Mo(n, np) 94 Nb reactions.

The recent high-precision measurements of $\ensuremath{\alpha}$-particle-induced-reaction data below the Coulomb barrier ($B$) make possible the understanding of limits and possible improvement of a previous optical model potential (OMP) for $\ensuremath{\alpha}$ particles on nuclei within the mass number range $45\ensuremath{\le}A\ensuremath{\le}209$ [M. Avrigeanu et al., Phys. Rev. C 82, 014606 (2010)]. An updated version of this potential is given in the present work concerning mainly an increased surface imaginary-potential depth well below $B$ for $Ag130$. Moreover, underestimation of reaction cross sections for well-deformed nuclei is removed by using $\ensuremath{\sim}7%$ larger radius for the surface imaginary part of this spherical OMP. Improved input parameters based on recent independent data, particularly $\ensuremath{\gamma}$-ray strength functions, but no empirical rescaling factor of the $\ensuremath{\gamma}$ and/or neutron widths have been involved within statistical model calculation of the corresponding $(\ensuremath{\alpha},x)$ reaction cross sections.

The effective NN-interaction strength for the first NN collision in multistep reactions, averaged along the trajectory of the incident nucleon with respect to both the nuclear density and the first NN-collision probability, is obtained. Good agreement between the calculated values of this quantity and its phenomenological values is found. The account for the finite-range corrections to the involved local density approximation has a small effect on the average strength of the NN interaction. It is concluded that the nuclear-density dependence of the effective NN interaction may account for the phenomenological V{sub 0} values which have been underestimated at low energies when the trend of the optical-model potential only has been followed. {copyright} {ital 1997} {ital The American Physical Society}

An analysis is made of the various mechanisms contributing to the (n, d) reaction on the , and nuclei at incident energies up to 15 MeV. It is shown that the main contribution is given by the pick-up process. The statistical contributions are small, especially for . A model of the (n, d) knock-out reaction, in which restrictions on the available phase space for the proton and the neutron in the deuteron after the knock-out are imposed by a Pauli-blocking function, is suggested and applied. The model is close to that for quasi-deuteron photo-absorption and the knock-out model previously developed. It is shown that the knock-out contribution calculated within this model is generally small, but it leads to some improvement of the description of the existing data for the (n, d) reaction on the three nuclei considered in the low-energy interval.

The Neutrons For Science (NFS) facility is a component of SPIRAL-2 laboratory under construction at Caen (France). SPIRAL-2 is dedicated to the production of high intensity Radioactive Ions Beams (RIB). It is based on a high-power linear accelerator (LINAG) to accelerate deuterons beams in order to produce neutrons by breakup reactions on a C converter. These neutrons will induce fission in 238U for production of radioactive isotopes. Additionally to the RIB production, the proton and deuteron beams delivered by the accelerator will be used in the NFS facility. NFS is composed of a pulsed neutron beam and irradiation stations for cross-section measurements and material studies. The beams delivered by the LINAG will allow producing intense neutron beams in the 100 keV-40 MeV energy range with either a continuous or quasi-mono-energetic spectrum. At NFS available average fluxes will be up to 2 orders of magnitude higher than those of other existing time-of-flight facilities in the 1 MeV - 40 MeV range. NFS will be a very powerful tool for fundamental physics and application related research in support of the transmutation of nuclear waste, design of future fission and fusion reactors, nuclear medicine or test and development of new detectors. The facility and its characteristics are described, and several examples of the first potential experiments are presented., JRC.D.4-Standards for Nuclear Safety, Security and Safeguards

A model of (n, alpha ) knockout reactions, in which restrictions on the available phase space for the four nucleons of the alpha particle after the knockout are imposed by a Pauli-blocking function, is developed and applied to analyse excitation functions of (n, alpha ) reactions on 48Ti, 51V, 52Cr, 54Fe, 55Mn and 59Co nuclei. It is shown that Pauli-blocking effects are important for describing (n, alpha ) processes. A sensitivity study of the results for the values of the model parameters, namely the local Fermi energy at the nuclear surface from where knockout occurs and the alpha-particle preformation factor, shows that the ranges of their variations are quite limited.

An analysis of the $^{231}$Pa$(d,3n)$$^{230}$U reaction excitation function at energies around the Coulomb barrier has taken into account the pre-equilibrium and compound-nucleus cross sections corrected for the deuteron-breakup decrease of the total reaction cross section, as well as the inelastic breakup enhancement. The analysis reveals the dominance of the deuteron breakup mechanism unlike a former assessment in this respect of the deuteron-induced fission process.

Recent accurate data obtained for the isomeric cross section of the 197 Au(n, 2n) reaction provides an effective opportunity to consider the question of the effective moment of inertia of the nucleus within a consistent model analysis of all available reaction data for the 197 Au target nucleus. Moreover, since the corresponding model assumptions are better validated by analysis of the data above 20-30 MeV where only several data with large uncertainties are known, the usefulness of further measurements to be performed at large-scale facilities as SPIRAL-2 and n TOF, for incident energies up to 40 as well as 100 MeV, are underlined.

A set of global optical potentials for alpha particles with energies above 80 MeV has been extended to lower energies and proved appropriate to describe (n,\ensuremath{\alpha}) reactions. It is found that the transmission coefficients for alpha-particle emission are rather strongly related to the fusion cross sections and elastic scattering at energies above 80 MeV, but not to elastic scattering at lower energy where specific features are comprised within complex optical potential parametrizations.

The activation cross sections of (d,p), (d,2n), (d,3n), and (d,2p) reactions on {sup 63,65}Cu were measured in the energy range from 4 to 20 MeV using the stacked-foil technique. Then, following the available elastic-scattering data analysis that provided the optical potential for reaction cross-section calculations, an increased effort was devoted to the breakup mechanism, direct reaction stripping, and pre-equilibrium and compound-nucleus cross-section calculations, corrected for the breakup and stripping decrease of the total reaction cross section. The overall agreement between the measured and calculated deuteron activation cross sections proves the correctness of the nuclear mechanism account, next to the simultaneous analysis of the elastic-scattering and reaction data.

The cross sections of the {sup 115}Sn({alpha},{gamma}){sup 119}Te, {sup 115}Sn({alpha},n){sup 118}Te, and {sup 116}Sn({alpha},n){sup 119}Te reactions (both on ground and isomeric states) have been measured at effective center-of-mass energies from 9.3 to 14.8 MeV. During a first experiment, enriched self-supporting {sup 115}Sn (51.2%) + {sup 116}Sn (24.4%) foils were bombarded with an {alpha} beam delivered by the Bucharest IFIN-HH Tandem Accelerator. In a second experiment, a highly enriched {sup 116}Sn target was irradiated in order to disentangle the experimental cross section contributions due to {sup 115}Sn({alpha},{gamma}){sup 119}Te and {sup 115}Sn({alpha},n){sup 118}Te reactions obtained in the first measurement. The beam-induced activity was measured with two large volume HPGe detectors in close geometry. The experimental results were compared with theoretical predictions obtained in the framework of the statistical model.

An extended analysis of the nuclear reaction mechanisms involved in the deuterons interaction with 63,65 Cu is presented. First, the available elastic-scattering data analysis provide d us the optical potential for reac- tion cross sections calculations. An increased effort has been devoted to the breakup mechanism, both the elastic breakup and the breakup fusion contributions to the different activation cross sections being carefully considered. Next, the direct reaction contributions through the one nucleon stripping re action cross sections have been cal- culated. Finally, the pre-equilibrium and compound-nucleus cross-section calculation, corrected for the breakup and stripping decrease of the total reaction cross section, completed the d euteron activation cross-section anal- ysis. The overall agreement between the measured and calculated deuteron activation cross sections proves the correctness of the nuclear mechanisms account.