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Highlights: [•] Pumping start is modeled by an immediate shift between two steady-state flow fields. [•] Ages deduced from CFCs and SF6 concentrations evolve in two distinct phases. [•] Transient flow patterns affect ages just after the pumping start but quickly vanish. [•] Atmospheric concentrations then transiently weight the residence time distribution. [•] Similar in terms of magnitude, these two regimes are helpful for models segregation. [Copyright &y& Elsevier]

Summary: Groundwater resources in crystalline rock are typically associated with the weathered zone and regional sub-vertical faults that are well connected to the surface. However, some sub-horizontal and shallowly dipping fractured zones can also be highly-productive aquifers. In this paper, numerical simulations of a conceptual hydrogeological model show that the flow to such strongly transmissive fractured zones is controlled by their transmissivity or by their deepening structure. While leakage through the overlying rock units is generally the limiting factor, recharge always occurs at least close to the outcrop of the fractured zone where the overlying rock is thinner and guarantees the availability of some groundwater. At small dip angles, recharge extends spatially and the flow within the fractured zone may even become the limiting factor when the hydraulic conductivity of the overlying rock is not less than two orders of magnitude smaller than the fractured zone transmissivity. This is precisely the case of the Plœmeur aquifer (Brittany, France) located in a crystalline rock geologic setting, where groundwater in a shallowly dipping fractured zone is used as the source of water supply for a nearby city of 20,000 people. Simulation results show that the fractured zones may represent potential aquifers under a large variety of hydrogeological conditions. Aquifers in shallowly dipping structures differ strongly from those located in regional sub-vertical fault zones in terms of flow patterns, and thus supposedly in terms of management of the groundwater resource. They are more local than regional in scale, and consequently do not require regional fracture connectivity. The leakage through the overlying rock unit enhances water quality. Finally, we argue that the potential widespread occurrence of these alternative and possibly less accessible resources should promote the development of appropriate identification methods. [Copyright &y& Elsevier]

Summary: Environmental tracers have been extensively used to get characteristic groundwater velocities. When sampled in discharge zones, we show that they can also be efficiently used to get more integrative information on aquifer structure, which is especially valuable in complex geological settings like hard-rock contexts. Used in combination with generally available hydraulic data, they give useful prediction of the residence time distribution. Our analysis is illustrated on the produced crystalline aquifer of Plœmeur (Brittany, France) formed at a dipping contact zone between granites and micaschists. Although constrained on the same hydraulic head and CFC-12 data sampled at the produced well, full steady-state hydrogeological models and simpler exponential-like models yield predictions of the renewal rate and of the cumulative residence time that may differ by a factor 2. Differences come predominantly from the km-scale geological structures and topographical features that cannot be resolved by statistical models and are nonetheless essential within the characteristic dating range of the CFCs (0–70years). Our analysis highlights the interest of combining hydraulic and age information for the prediction of residence time distributions within full hydrogeological models, and the capacity of identifying global hydrogeological structures from point-like data. [ABSTRACT FROM AUTHOR]

Abstract: Reliable predictions of light charged particle production in spallation reactions are important to correctly assess gas production in spallation targets. In particular, the helium production yield is important for assessing damage in the window separating the accelerator vacuum from a spallation target, and tritium is a major contributor to the target radioactivity. Up to now, the models available in the MCNPX transport code, including the widely used default option Bertini–Dresner and the INCL4.2–ABLA combination of models, were not able to correctly predict light charged particle yields. The work done recently on both the intranuclear cascade model INCL4, in which cluster emission through a coalescence process has been introduced, and on the de-excitation model ABLA allows correcting these deficiencies. This paper shows that the coalescence emission plays an important role in the tritium and production and that the combination of the newly developed versions of the codes, INCL4.5–ABLA07, now lead to good predictions of both helium and tritium cross-sections over a wide incident energy range. Comparisons with other available models are also presented. [Copyright &y& Elsevier]

Abstract: We measured integral thin target cross sections for the proton-induced production of He-, Ne-, Ar-, Kr- and Xe-isotopes from bismuth (Bi) from the respective reaction thresholds up to 2.6GeV. Here we present 275 cross sections for 23 nuclear reactions. The production of noble gas isotopes from Bi is of special importance for design studies of accelerator driven systems (EA/ADS) and nuclear spallation sources. For experiments with proton energies above 200MeV the mini-stack approach was used instead of the stacked-foil technique in order to minimise the influences of secondary particles on the residual nuclide production. Comparing the cross sections for Bi to the data published recently for Pb indicates that for 4He the cross sections for Bi below 200MeV are up to a factor of 2–3 higher than the Pb data, which can be explained by the production of α-decaying Po-isotopes from Bi but not from Pb. Some of the cross sections for the production of 21Ne from Bi are affected by recoil effects from neighboured Al-foils, which compromises a study of a possible lowering of the effective Coulomb-barrier. The differences in the excitation functions between Pb and Bi for Kr- and Xe-isotopes can be explained by energy-dependent higher fission cross sections for Bi compared to Pb. The experimental data are compared to results from the theoretical nuclear model codes INCL4/ABLA and TALYS. The INCL4/ABLA system describes the cross sections for the production of 4He-, Kr- and Xe-isotopes reasonably well, i.e. mostly within a factor of a few. In contrast, the model completely fails describing 21Ne, 22Ne, 36Ar and 38Ar, which are produced via spallation and/or multifragmentation. The TALYS code is only able to accurately predict reaction thresholds. The absolute values are either significantly over- or underestimated. Consequently, the comparison of measured and modelled thin target cross sections clearly indicates that experimental data are still needed because the predictive power of nuclear model codes, though permanently improving, does still not allow to reliably predict the cross sections needed for most applications and irradiation experiments remain indispensable. [Copyright &y& Elsevier]

A model is proposed to describe emission of light charged clusters during the cascade stage in nucleon-induced spallation reactions. It consists in implementing a surface percolation procedure into the Liège intranuclear cascade (INCL4) model: when a nucleon is ready to leave the nuclear surface, it is allowed to drag along a cluster of nucleons, under some conditions of closeness in phase space. This possibility relies on the instantaneous dynamical phase space occupancy in the nuclear surface. The following clusters are considered: d,t,3He,4He. Good agreement is obtained with experimental data relative to heavy and medium-heavy targets at two different energies. It is shown that the implementation of light cluster emission in the cascade stage also improves our previous results for residue mass spectra. [Copyright &y& Elsevier]

The paper presents the measured cumulative yields of 44 Ti for nat Cr, 56 Fe, nat Ni and 93 Nb samples irradiated by protons at the energy range 0.04–2.6 GeV. The obtained excitation functions are compared with calculations of the well-known codes: ISABEL, Bertini, INCL4.2+ABLA, INCL4.5+ABLA07, PHITS, CASCADE07 and CEM03.02. The predictive power of these codes regarding the studied nuclides is analyzed. [ABSTRACT FROM AUTHOR]

Residual fragment production in reactions induced by 136Xe projectiles impinging on a liquid deuterium target at 500A MeV has been measured at GSI. Projectile residues were unambiguously identified in atomic and mass numbers using the Fragment Separator as high-resolution zero-degree spectrometer. The isotopic production yields of these residuals were used to benchmark reference model calculations describing spallation reactions. In particular the energy dissipated in these reactions was assessed by comparing the production yields measured in this work with the ones obtained in reactions induced by 136Xe projectiles on protons at 1000A and 500A MeV. [ABSTRACT FROM AUTHOR]

Proton induced nuclear reactions were measured with stacked-foil technique on natural uranium targets in the energy range from 211 to 2,530 MeV at the Saturne II synchrocyclotron at the Laboratoire National Saturne/Saclay (France). Twenty-three reactions were determined by means of off-line γ-spectrometry. The obtained excitation functions have been compared with the earlier published data and the theoretical model INCL4 + ABLA. [ABSTRACT FROM AUTHOR]

Summary While central in groundwater resources and contaminant fate, Transit Time Distributions (TTDs) are never directly accessible from field measurements but always deduced from a combination of tracer data and more or less involved models. We evaluate the predictive capabilities of approximate distributions (Lumped Parameter Models abbreviated as LPMs) instead of fully developed aquifer models. We develop a generic assessment methodology based on synthetic aquifer models to establish references for observable quantities as tracer concentrations and prediction targets as groundwater renewal times. Candidate LPMs are calibrated on the observable tracer concentrations and used to infer renewal time predictions, which are compared with the reference ones. This methodology is applied to the produced crystalline aquifer of Plœmeur (Brittany, France) where flows leak through a micaschists aquitard to reach a sloping aquifer where they radially converge to the producing well, issuing broad rather than multi-modal TTDs. One, two and three parameters LPMs were calibrated to a corresponding number of simulated reference anthropogenic tracer concentrations (CFC-11, 85 Kr and SF 6 ). Extensive statistical analysis over the aquifer shows that a good fit of the anthropogenic tracer concentrations is neither a necessary nor a sufficient condition to reach acceptable predictive capability. Prediction accuracy is however strongly conditioned by the use of a priori relevant LPMs. Only adequate LPM shapes yield unbiased estimations. In the case of Plœmeur, relevant LPMs should have two parameters to capture the mean and the standard deviation of the residence times and cover the first few decades [0; 50 years]. Inverse Gaussian and shifted exponential performed equally well for the wide variety of the reference TTDs from strongly peaked in recharge zones where flows are diverging to broadly distributed in more converging zones. When using two sufficiently different atmospheric tracers like CFC-11 and 85 Kr, groundwater renewal time predictions are accurate at 1–5 years for estimating mean transit times of some decades (10–50 years). 1-parameter LPMs calibrated on a single atmospheric tracer lead to substantially larger errors of the order of 10 years, while 3-parameter LPMs calibrated with a third atmospheric tracers (SF 6 ) do not improve the prediction capabilities. Based on a specific site, this study highlights the high predictive capacities of two atmospheric tracers on the same time range with sufficiently different atmospheric concentration chronicles. [ABSTRACT FROM AUTHOR]

Abstract: A new approach to describing neutron spectra of deuteron-induced reactions in the Monte Carlo simulation for particle transport has been developed by combining the Intra-Nuclear Cascade of Liège (INCL) and the Distorted Wave Born Approximation (DWBA) calculation. We incorporated this combined method into the Particle and Heavy Ion Transport code System (PHITS) and applied it to estimate spectra on natLi, 9Be, and natC targets at incident energies ranging from 10 to 40MeV. Double differential cross sections obtained by INCL and DWBA successfully reproduced broad peaks and discrete peaks, respectively, at the same energies as those observed in experimental data. Furthermore, an excellent agreement was observed between experimental data and PHITS-derived results using the combined method in thick target neutron yields over a wide range of neutron emission angles in the reactions. We also applied the new method to estimate spectra in the reactions, and discussed the validity for the proton emission spectra. [Copyright &y& Elsevier]

Total fission cross sections of 18Ta induced by protons at different relativistic energies have been measured at GSI Darmstadt using the inverse kinematic technique. These data contribute to solve inconsistencies in previously reported measurements, but also help to benchmark state-of-the-art reaction codes. The energy range covered with these measurements allowed us to investigate the onset and temperature dependence of dissipative and transient effects at small deformation. [ABSTRACT FROM AUTHOR]

Highlights: [•] We propose hydrogeological conceptual model of fault aquifer in crystalline basement. [•] We characterize interactions between a fault aquifer and surrounding compartments. [•] Sub-vertical fault resource is strongly dependent on superficial aquifer storage. [•] We estimate groundwater resource availability. [Copyright &y& Elsevier]

Inclusive multineutron and multiproton removal cross sections from 112Sn and 104Sn at relativistic energies have been measured. The data show two distinct regimes of the reaction process that depend on the nucléon evaporation cost of the final nucleus. This behavior is universal by regarding the mass or asymmetry of the initial system or target composition. A state-of-the-art cascade and deexcitation model reproduces the observed trend but systematically fails in reproducing cross sections for the removal of the more bound nucléon species. [ABSTRACT FROM AUTHOR]

Total cross sections for proton- and deuteron-induced-fission of 208Pb and 238U have been determined in the energy range between 500 MeV and 1 GeV. The experiment has been performed in inverse kinematics at GSI Darmstadt, facilitating the counting of the projectiles and the identification of the reaction products. High precision between 5% and 7% has been achieved by individually counting the beam particles and by registering both fission fragments in coincidence with high efficiency and full Z resolution. Fission was clearly distinguished from other reaction channels. The results were found to deviate by up to 30% from Prokofiev's systematics on total fission cross sections. There is good agreement with an elaborate experiment performed in direct kinematics. [ABSTRACT FROM AUTHOR]

Astatine isotopes can be produced in liquid lead-bismuth eutectic targets through proton-induced double charge exchange reactions on bismuth or in secondary helium-induced interactions. Models implemented into the most common high-energy transport codes generally have difficulties to correctly estimate their production yields as was shown recently by the ISOLDE Collaboration, which measured release rates from a lead-bismuth target irradiated by 1.4 and 1 GeV protons. In this paper, we first study the capability of the new version of the Liège intranuclear cascade model, INCL4.6, coupled to the deexcitation code ABLA07 to predict the different elementary reactions involved in the production of such isotopes through a detailed comparison of the model with the available experimental data from the literature. Although a few remaining deficiencies are identified, very satisfactory results are found, thanks in particular to improvements brought recently on the treatment of low-energy helium-induced reactions. The implementation of the models into MCNPX allows identifying the respective contributions of the different possible reaction channels in the ISOLDE case. Finally, the full simulation of the ISOLDE experiment is performed, taking into account the likely rather long diffusion time from the target, and compared with the measured diffusion rates for the different astatine isotopes, at the two studied energies, 1.4 and 1 GeV. The shape of the isotopic distribution is perfectly reproduced as well as the absolute release rates, assuming in the calculation a diffusion time between 5 and 10hours. This work finally shows that our model, thanks to the attention paid to the emission of high-energy clusters and to low-energy cluster induced reactions, can be safely used within MCNPX to predict isotopes with a charge larger than that of the target by two units in spallation targets, and, probably, more generally to isotopes created in secondary reactions induced by composite particles. [ABSTRACT FROM AUTHOR]

Abstract: Around 270 medium-mass residual nuclei, formed in spallation reactions induced by 136Xe projectiles impinging on a liquid hydrogen target at 500 A MeV, have been unambiguously identified at GSI using the magnetic spectrometer FRS. The individual production cross sections and the longitudinal momentum distributions have been determined with high accuracy. These data represent an important constraint for theoretical models describing spallation reactions. [Copyright &y& Elsevier]

The new version (INCL4.6) of the Liège intranuclear cascade (INC) model for the description of spallation reactions is presented in detail. Compared to the standard version (INCL4.2), it incorporates several new features, the most important of which are: (i) the inclusion of cluster production through a dynamical phase space coalescence model, (ii) the Coulomb deflection for entering and outgoing charged particles, (iii) the improvement of the treatment of Pauli blocking and of soft collisions, (iv) the introduction of experimental threshold values for the emission of particles, (v) the improvement of pion dynamics, (vi) a detailed procedure for the treatment of light-cluster-induced reactions taking care of the effects of binding energy of the nucléons inside the incident cluster and of the possible fusion reaction at low energy. Performances of the new model concerning nucleon-induced reactions are illustrated by a comparison with experimental data covering total reaction cross sections, neutron, proton, pion, and composite double-differential cross-sections, neutron multiplicities, residue mass and charge distributions, and residue recoil velocity distributions. Whenever necessary, the INCL4.6 model is coupled to the ABLA07 de-excitation model and the respective merits of the two models are then tentatively disentangled. Good agreement is generally obtained in the 200 MeV to 2 GeV range. Below 200 MeV and down to a few tens of MeV, the total reaction cross section is well reproduced and differential cross sections are reasonably well described. The model is also tested for light-ion induced reactions at low energy, below 100 MeV incident energy per nucleón. Beyond presenting the update of the INCL4.2 model, attention has been paid to applications of the new model to three topics for which some particular aspects are discussed for the first time. The first topic is the production of clusters heavier than alpha particle. It is shown that the energy spectra of these produced clusters are consistent with coalescence. The second topic regards the longitudinal residue recoil velocity and its fluctuations. Excellent results are obtained for these quantities. It addition, it is shown that the distributions of these quantities display typical random-walk characteristics, at least for not-too-large mass losses. They are interpreted as a direct consequence of the independence of successive binary collisions occurring during the cascade process. The last topic concerns the total reaction cross section and the residue-production cross sections for low-energy incident light ions. It is shown that our new model can give a rather satisfactory account of these cross sections, offering so an alternative to fusion models and the advantage of a single model for the progressive change from fusion to pre-equilibrium mechanisms. [ABSTRACT FROM AUTHOR]

Nuclide production cross sections measured at the Institute for Theoretical and Experimental Physics (ITEP) for the targets of natCr, 55Fe, natNi, 93Nb, 18lTa, natW, natPb, and 209Bi irradiated by protons with energies from 40 to 2600 MeV were used to estimate the predictive accuracy of several popular high-energy transport codes. A general agreement of the ITEP data with the data obtained by other groups, including the numerous GSI data measured by the inverse kinematics method was found. Simulations of the measured data were performed with the MCNPX (BERTINI and ISABEL options), CEM03.02, INCL4.2 + ABLA, INCL4.5 + ABLA07, PHITS, and CASCADE.07 codes. Deviation factors between the calculated and experimental cross sections have been estimated for each target and for the whole energy range covered by our measurements. Two-dimensional diagrams of deviation factor values were produced for estimating the predictive power of every code for intermediate, not measured masses of nuclei targets and bombarding energies of protons. Further improvements of all tested here codes are recommended. In addition, new measurements at ITEP of nuclide yields from the 208Pb target irradiated by 500-MeV protons are presented. A good agreement between these new data and the GSI measurements obtained by the inverse kinematics method was found. [ABSTRACT FROM AUTHOR]

Abstract: The (MEGAWatt Pilot Experiment) MEGAPIE target was successfully irradiated in 2006 at the SINQ facility of the Paul Scherrer Institut. During the irradiation a series of measurements to monitor the operation of the target, the thermal hydraulics behavior and the neutronic and nuclear aspects, has been performed. In the post-test analysis phase of the project, the data were analyzed and important information relevant to accelerator-driven systems (ADS) was gained, in particular: (i) from the operation of the target several recommendations concern the simplification of the system and the improved reliability; (ii) data from the thermal hydraulic measurements have offered the opportunity to validate the codes used in the design phase; (iii) the neutronic analysis confirm the high performance of a liquid metal target and the importance of the delayed neutron measurements in an ADS target; (iv) the nuclear measurements of the gas released gave the opportunity to validate the codes used during the design phase and provided indications for the operation. From the results in these different domains recommendations to further development of ADS and heavy liquid metal targets are discussed. [Copyright &y& Elsevier]

Abstract: Radiation hazard for space missions is mainly due to cosmic ray protons, helium nuclei and light ions, whose energy spectrum is maximum around 1GeV per nucleon but remains non-negligible for energies up to 15GeV per nucleon. Nuclear reactions induced by high energy protons are often described by intranuclear cascade plus evaporation models. The attention is focused here on the Liège Intranuclear Cascade model (INCL), which has been shown to reproduce fairly well a great deal of experimental data for nucleon-induced reactions in the 200MeV to 2GeV range, when coupled with the ABLA evaporation-fission code. In order to extend the model to other conditions relevant for space radiation, three improvements of INCL are under development. They are reported on here. First, the reaction model has been extended to nucleon–nucleus reactions at incident energies up to 15GeV, mainly by the inclusion of additional pion production channels in nucleon–nucleon collisions during the cascade. Second, a coalescence mechanism for the emission of light charged particles has been implemented recently. Finally, the model has been modified in order to accommodate light ions as projectiles. First results are shown and compared with illustrative experimental data. Implications for issues concerning radiation protection in space are discussed. [Copyright &y& Elsevier]

The cross sections for nuclide production in thin Fe and Cr targets irradiated by 0.04-2.6-GeV protons are measured by direct γ spectrometry using two γ spectrometers with the resolutions of 1.8 and 1.7 keV for the Co 1332-keV γ line. As a result, 649 yields of radioactive residual product nuclei have been obtained. The Al( p, x)Na reaction has been used as a monitor reaction. The experimental data are compared with the MCNPX (BERTINI, ISABEL), CEM03.02, INCL4.2, INCL4.5, PHITS, and CASCADE07 calculations. [ABSTRACT FROM AUTHOR]

The cross sections for nuclide production in thin Wand Ta targets irradiated by 0.04-2.6-GeV protons have been measured by direct γ spectrometry using two γ spectrometers with the resolutions of 1.8 and 1.7 keV in the Co 1332-keV γ line. As a result, 1895 yields of radioactive residual product nuclei have been obtained. The Al( p, x)Na reaction has been used as a monitor reaction. The experimental data have been compared with the MCNPX (BERTINI, ISABEL), CEM03.02, INCL4.2, INCL4.5, PHITS, and CASCADE07 calculations. [ABSTRACT FROM AUTHOR]

The cross sections for nuclide production in thin Nb and Ni targets irradiated by 0.04- to 2.6-GeV protons have been measured by direct γ spectrometry using two γ spectrometers with the resolutions of 1.8 and 1.7 keV in the Co 1332-keV γ line. As a result, 1112 yields of radioactive residual nuclei have been obtained. The Al( p, x)Na reaction has been used as a monitor reaction. The experimental data have been compared with the MCNPX (BERTINI, ISABEL), CEM03.02, INCL4.2, INCL4.5, PHITS, and CASCADE07 calculations. [ABSTRACT FROM AUTHOR]

The cross sections for the production of Gd in W and Ta targets irradiated by 0.4-, 0.6-, 0.8-, 1.2-, 1.6-, and 2.6-GeV protons at the ITEP accelerator complex have been measured by direct α spectrometry without chemical separation. The experimental data have been compared with the data obtained at other laboratories and with the theoretical simulations of the yields on the basis of the BERTINI, ISABEL, CEM03.02, INCL4.2, INCL4.5, CASCADE07, and PHITS codes. [ABSTRACT FROM AUTHOR]

Abstract: The intranuclear cascade model INCL4 has been shown to be very successful for describing, without adjustable parameters, a whole set of data for p-induced reactions in the 40MeV–2GeV energy range. In view of its possible application to cosmic ray interactions, the INCL4 code has been extended to the 2–15GeV energy range, so covering a large part of the spectrum of the incident energy of the cosmic rays. In this paper, the changes brought into the INCL4 code are discussed and some illustrative comparisons between the results given by the modified version of the code and experimental data are presented. [Copyright &y& Elsevier]

Abstract: The Liège intranuclear cascade (INCL) model is shortly presented. The predictive power of its standard version concerning the description of nucleon-induced spallation reactions in the 200MeV to 2GeV range of incident energy is indicated. Current improvements of the model, in particular its extension to higher energies, are emphasized. The capabilities of the model for possible applications in astrophysics, space research and protontherapy are pointed out. [Copyright &y& Elsevier]

Abstract: We measured integral thin target cross-sections for the proton-induced production of He-, Ne-, Ar-, Kr-, and Xe-isotopes from lead and bismuth from the respective reaction threshold up to 2.6GeV. The production of noble gas isotopes from lead and bismuth is of special importance for design studies of accelerator driven nuclear reactors and/or energy amplifiers. For all experiments with proton energies above 200MeV a new mini-stack approach was used instead of the stacked-foil technique in order to minimise influences of secondary particles. The phenomenology of the determined excitation functions enables us to distinguish between the different reaction modes fragmentation, hot and cold symmetric fission, asymmetric fission, and deep spallation. For lead more than 420 cross-sections for 23 nuclear reactions have been measured. While the lead data have already been published, here we present first results for the production of noble gas isotopes from bismuth. The experimental data are compared to results from the theoretical nuclear model code INCL4/ABLA. This comparison clearly indicates that experimental data are still needed because the predictive power of nuclear model codes, though permanently improving, does still not allow to reliably predict the cross-sections needed for most applications and irradiation experiments remain indispensable. [Copyright &y& Elsevier]

Abstract: A new type of spallation experiments has been carried out at GSI, Darmstadt (Germany) in order to understand the spallation mechanism in greater details. These experiments use the inverse-kinematics technique where the ion beam is directed onto a liquid Hydrogen target, allowing the detection of heavy spallation residues in coincidence with low center-of-mass energy light particles. The setup is based on A Large Acceptance DIpole magNet (ALADIN) coupled with a multitrack Time Projection Chamber (TPC), a hodoscope and a neutron detector. First, data on at 1AGeV were taken in February 2004. In the on-going analysis, isotopic cross-sections have been determined and compared to data taken at the FRagment Separator in GSI. Mean values and width of residue velocity distributions have also been obtained as well as Helium production cross-section. First, coincidence data are being analyzed. [Copyright &y& Elsevier]

Abstract: The production cross sections of fragmentation–evaporation residues in the reaction at have been measured using the inverse-kinematics method and the FRS spectrometer (GSI). Fragments were identified in nuclear charge using ionisation chambers. The mass identification was performed event-by-event using the technique. Although partially-unresolved ionic charge states induced an ambiguity on the mass of some heavy fragments, production rates could be obtained with a high accuracy by systematically accounting for the polluting ionic charge states. The contribution of multiple reactions in the target was subtracted using a new, partly self-consistent code. The isobaric distributions are found to have a shape very close to the one observed in experiments at higher energy. Kinematic properties of the fragments were also measured. The total and the isotopic cross sections, including charge-pickup cross sections, are in good agreement with previous measurements and models. The data are discussed in the light of previous spallation measurements, especially on lead at 1 GeV. [Copyright &y& Elsevier]

Abstract: Fission fragments from GeV 238U ions impinging a hydrogen target are investigated by using the fragment separator FRS for magnetic selection of reaction products including ray-tracing, and ΔE-ToF techniques. On the basis of the kinematics of the fragments, binary fission can be assigned as production process up to very heavy fragments. Fission fragments are separated and identified as far as 184Re for the first time. Cross sections are measured and found in the range of 500 μb to 5 μb. Isobaric cross sections decrease smoothly with increasing masses. Beyond tungsten, fission fragments are hidden in the more abundant spallation evaporation residues. 283 isotopes of elements gadolinium to rhenium in the mass range 147 to 184 are observed and cross sections measured. All the fragments are formed by fission of excited parent nuclei following emission of a cascade of secondary neutrons. [Copyright &y& Elsevier]

Abstract: The mean N-over-Z (/Z) ratio of residues produced in the fragmentation of 136Xe (N/Z=1.519), 124Xe (N/Z=1.296) in comparison with 56Fe (N/Z=1.154) is investigated over the full range of Z. The final residues from the 136Xe projectile keep a memory on the initial N/Z. The idea to trace back the excitation energy of the fragment entering evaporation via direct exploration of the N/Z evolution in the evaporation process is investigated and applied to the data. The freeze-out temperature is deduced, which is consistent with the investigations of light and intermediate-mass fragments (IMF) in other experiments. [Copyright &y& Elsevier]

Abstract: We measured integral thin target cross sections for the proton-induced production of He-, Ne-, Ar-, Kr- and Xe-isotopes from lead from the respective reaction threshold up to 2.6 GeV. The production of noble gas isotopes from lead is of special importance for design studies of accelerator driven nuclear reactors and/or energy amplifiers. For all experiments with proton energies above 200 MeV a new mini-stack approach was used instead of the stacked-foil technique in order to minimise the influences of secondary particles on the residual nuclide production. About 420 cross sections for 23 nuclear reactions were determined. The phenomenology of the determined excitation functions enables us to distinguish between the different reaction modes fragmentation, hot and cold symmetric fission, asymmetric fission and deep spallation. Cross sections for the production of 21Ne and 38Ar measured below 100 MeV and 200 MeV, respectively, enable us to study nuclide production below the nominal Coulomb-barrier. The experimental data are compared to results from the theoretical nuclear model code INCL4/ABLA. While the model describes the production of 4He reasonably well, it underestimates the cross sections for Ne- and Ar-isotopes produced via deep spallation and/or multifragmentation by up to two orders of magnitude. For the Kr- and Xe-isotopes the agreement between modelled and measured data strongly depends on the reaction mechanisms. While INCL4/ABLA describes the production of n-poor Kr-isotopes via hot-symmetric fission and the production of Xe-isotopes via asymmetric fission reasonably well, i.e. within a factor of 2, the discrepancies between modelled and measured cross sections for the n-rich Kr-isotopes produced via cold symmetric fission are significantly larger. For the Xe-isotopes produced via spallation, i.e. at energies higher than about 600 MeV, the model completely fails to describe the experimental data. Therefore, the comparison of measured and modelled thin target cross sections clearly indicates that experimental data are still needed because the predictive power of nuclear model codes, though permanently improving, does still not allow to reliably predict the cross sections needed for most applications and irradiation experiments remain indispensable. [Copyright &y& Elsevier]

Abstract: The isotopic distributions and recoil velocities of the fission fragments produced in the spallation reaction 208Pb + p at 500 A MeV have been measured using the inverse-kinematics technique, a lead beam onto a liquid-hydrogen target, and the high-resolution spectrometer FRS at GSI. The shapes of the different distributions are found in good agreement with previously published data while the deduced total fission cross-section is higher than expected from existing systematics and some previous measurements. From the experimental data, the characteristics of the average fissioning system can be reconstructed in charge, mass and excitation energy, and the average number of post-fission neutrons can be inferred. The results are also compared to different models describing the spallation reaction. The intranuclear cascade code INCL4 followed by the de-excitation code ABLA is shown to describe reasonably well the evolution of the isotopic distribution shapes between 500 and 1000 A MeV. [Copyright &y& Elsevier]

A systematic investigation of the isotopic cross sections of nuclear residues produced in the reactions 238U (1 A GeV)+p,d has been performed with the high-resolution magnetic spectrometer FRS at GSI. The large range of excitation energies induced in these reactions, together with the high fissility of uranium-like systems constitute an optimum scenario to study the dynamics of spallation reactions. In particular, some fundamental questions connected to the role of dissipation and the onset of a break-up stage at high temperatures can be addressed with these data. [Copyright &y& Elsevier]