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The CEA in collaboration with ILL and LPSC has developed a measurement program on symmetric and heavy mass fission product distributions. The combination of measurements with ionisation chamber and Ge detectors is necessary to describe precisely the heavy fission product region in mass and charge. Recently, new measurements of fission yields and kinetic energy distributions, for different fissioning systems (233,235 U(nth, f),241 Am(2nth, f) and 239,241 Pu(nth, f), were performed with recoil spectrometer LOHENGRIN. The focus has been done on the self-normalization of the data to provide new absolute measurements, independently of any libraries along with the experimental covariance matrix. To reach precise measurements, a new experimental procedure was developed along with a new analysis method.

Nuclear fission yields are key parameters to evaluate reactor physics observables, such as fuel inventory, decay heat, spent fuel radiotoxicity, criticality but also for understanding the fission process. Despite a significant effort allocated to measure fission yields during the last decades, the recent evaluated libraries still need improvements in particular in the description of the uncertainties with the associated correlations. Additional kinds of measurements provide complementary information in order to test the models used in the nuclear data evaluation. Moreover, some discrepancies between these libraries must be explained. A common effort by the CEA, the LPSC and the ILL aims at tackling these issues by providing precise measurement of isotopic and isobaric fission yields with the related variance-covariance matrices. Nevertheless, the experimental program represents itself a large range of observables requested by the evaluations: isotopic yields, nuclear charge polarization, odd-even effect, isomeric ratio and their dependency with fission fragment kinetic energy as a probe of the nuclear de-excitation path in the (E*, Jπ) representation. Measurements for thermal neutron induced fission of 241Pu have been carried out at the Institut Laue Langevin using the LOHENGRIN mass spectrometer. Experimental program, observables reachable, results and comparison to model calculations are shown.

The main goal of this work is the determination of spins and parities of excited states in $^{97}\mathrm{Zr}$, among others the 2264.3-keV level, which had previously been tentatively reported as the $11/{2}^{\ensuremath{-}}$ excitation corresponding to the ${h}_{11/2}$ neutron orbital. Low-spin excited states in $^{97}\mathrm{Zr}$ were populated via the cold-neutron capture reaction. The $\ensuremath{\gamma}$ rays emitted following the reaction were measured using the highly efficient array of high-purity germanium detectors, EXILL, at the Institut-Laue-Langevin (ILL), Grenoble. The primary $\ensuremath{\gamma}$ rays deexciting the capture state in $^{97}\mathrm{Zr}$ were identified for the first time. The new, precise neutron binding energy in $^{97}\mathrm{Zr}$ of 5569.15(4) keV differs significantly from the value reported in the literature. The previously reported level scheme has been amended by several new low-spin levels. The ($n,\ensuremath{\gamma}$) data were complemented by a measurement of the ${\ensuremath{\beta}}^{\ensuremath{-}}$ decay of $^{97}\mathrm{Y}$ at the Lohengrin fission-fragment separator of the ILL, and the observation of the ${\ensuremath{\beta}}^{\ensuremath{-}}$ decay of $^{97}\mathrm{Y}$ populated in neutron-induced fission of $^{235}\mathrm{U}$ and measured using the EXILL Ge array. The combined data allowed unique spin-parity assignments for many levels in $^{97}\mathrm{Zr}$. The 2264.3-keV level, with a new spin-parity assignment of $9/{2}^{+}$, may correspond to the $\ensuremath{\nu}{g}_{9/2}$ extruder orbital.

International audience; The Fission Product Prompt γ-ray Spectrometer (FIPPS) is a new instrument of the Institut Laue-Langevin (ILL) for the spectroscopy of nuclei produced after neutron induced reactions. The future upgrade of the instrument aims to explore the neutron-rich region of the nuclear chart with higher selectivity by identifying the fragments produced after neutron induced fission. The Gas-Filled-Magnet (GFM) technique has been chosen in order to obtain a good mass separation (50 msr and P/P > 10%). A GFM design consisting of a 1/r magnetic field index and Thales circle-shaped entrance and exit magnet edges is proposed. The characteristic of the magnet is presented with realistic magnetic field calculations and Monte-Carlo simulations.

In this article we report on the observation of new yrast and non-yrast states in $^{136}\mathrm{I}$, populated in the prompt-$\ensuremath{\gamma}$ spectroscopy EXILL campaign at the ILL using both $^{235}\mathrm{U}$(n,f) and $^{241}\mathrm{Pu}$(n,f) reactions. We propose an extension of the level scheme and interpretation of the new spectroscopic results in comparison to state-of-the-art shell-model calculations. We discuss the role of the proton ${d}_{5/2}$ orbital in the structure of this nucleus with $Z=53$ and the energy split between the $\ensuremath{\pi}{d}_{5/2}\phantom{\rule{0.28em}{0ex}}\text{and}\phantom{\rule{0.28em}{0ex}}\ensuremath{\pi}{g}_{7/2}$ orbitals. We also provide a complete overview of all experimental information about this nucleus and include new data from $^{252}\mathrm{Cf},^{248}\mathrm{Cm}$ fission and $\ensuremath{\beta}$ decay of $^{136}\mathrm{Te}$ to $^{136}\mathrm{I}$. We give a new interpretation of $^{136}\mathrm{I}$ and its decay to $^{136}\mathrm{Xe}$ in terms of the influence of the neutron ${h}_{9/2}$ orbital and the Gamow-Teller strength for $N=83$.

Delayed $\ensuremath{\gamma}$-ray and conversion-electron spectroscopy is performed on $A=152$ fission fragments, at the Lohengrin spectrometer of the Institut Laue-Langevin, providing a new decay scheme for $^{152}\mathrm{Pr}$. The quasiparticle phonon model, combined with the particle-rotor model, which allows octupole correlations and Coriolis mixing to be taken into account, is applied to analyze its low-energy structure. The main configurations are found to be $(\ensuremath{\pi}3/2[422]\ensuremath{\bigotimes}\ensuremath{\nu}5/2[642]){1}^{+}$ for the isomer and $(\ensuremath{\pi}3/2[541]\ensuremath{\bigotimes}\ensuremath{\nu}3/2[521]){3}^{+}$ for the ground state.

Excited states in $^{98}\mathrm{Y}$, populated in neutron-induced fission of $^{235}\mathrm{U}$ and in spontaneous fission of $^{248}\mathrm{Cm}$ and $^{252}\mathrm{Cf}$, have been studied by means of $\ensuremath{\gamma}$ spectroscopy using the Lohengrin fission-fragment separator at ILL Grenoble and the EXILL, Eurogam2, and Gammasphere Ge arrays. Two new isomers have been found in $^{98}\mathrm{Y}$: a deformed one with ${T}_{1/2}=180(7)$ ns and a rotational band on top of it, and a spherical one with ${T}_{1/2}=0.45(15)\phantom{\rule{4pt}{0ex}}\ensuremath{\mu}\text{s}$, analogous to the ${8}^{+}$ isomer in $^{96}\mathrm{Y}$, corresponding to the ${(\ensuremath{\nu}{g}_{7/2},\ensuremath{\pi}{g}_{9/2})}_{{8}^{+}}$ spherical configuration. Using the JYFLTRAP Penning trap, an accurate excitation energy of 465.7(7) keV has been determined for the 2.36-s isomer in $^{98}\mathrm{Y}$. This result and the studies of excited levels in $^{98}\mathrm{Zr}$, populated in ${\ensuremath{\beta}}^{\ensuremath{-}}$ decay of the isomer, indicate a new spin-parity, ${I}^{\ensuremath{\pi}}={(7)}^{+}$ for the isomer. The high spin and the decay properties of this isomer suggest the presence of the $9/{2}^{+}[404]$ neutron extruder orbital in its structure. This is consistent with the large deformation of the isomer, reported recently. The present work does not provide arguments to support the special role of the $\ensuremath{\nu}{g}_{7/2}\phantom{\rule{0.16em}{0ex}}\text{\ensuremath{-}}\phantom{\rule{0.16em}{0ex}}\ensuremath{\pi}{g}_{9/2}$ interaction (the spin-orbit-partner, or SOP, mechanism).

The fission fragment yield distribution has been measured in the $^{239}\mathrm{Pu}\left({n}_{\mathrm{th}},f\right)$ reaction in the mass region of $A=126$ to 150 using the Lohengrin recoil-mass spectrometer. Three independent experimental campaigns were performed, allowing a significant reduction of the uncertainties compared to evaluated nuclear data libraries. The long-standing discrepancy of around 10% for the relative yield of $A=134$ reported in JEF-2.2 and JEFF-3.1.1 data libraries is finally solved. Moreover, the measured mass distribution in thermal neutron-induced fission does not show any significant dip around the shell closure ($A=136$) as seen in heavy-ion fission data of $^{208}\mathrm{Pb}$($^{18}\mathrm{O}$, $f$) and $^{238}\mathrm{U}$($^{18}\mathrm{O}$, $f$) reactions. Lastly, comparisons between our experimental data and the predictions from Monte Carlo codes (gef and fifrelin) are presented and discussed.

International audience; FIPPS is the new nuclear physics instrument of ILL for the spectroscopy of nuclei produced in neutron-induced reactions. The performance of the first implementation of the setup will be shown, together with an overview of the first experimental campaign (December 2016-March 2017). Future perspectives and physics opportunities will then be discussed.

Isomeric ratios are a powerful observable to investigate fission fragment total angular momenta. A recent experimental campaign achieved at the LOHENGRIN spectrometer, shows a kinetic energy dependence of μs isomeric ratios from fission fragments populated in neutron induced fission of 235U. For the first time, this dependence was measured for the isomeric ratio of the doubly magic 132Sn. A Bayesian assessment of the angular momentum distribution of 132Sn is proposed according to calculations performed with the FIFRELIN code and interpreted with spin generation models. Keywords: Isomeric ratio, Mass spectrometer, Angular momentum distribution, Fission fragment

Accurate thermal neutron-induced fission data are important for applications in reactor physics as well as for fundamental nuclear physics. FIPPS is the new FIssion Product Prompt γ-ray Spectrometer being developed at the Institut Laue Langevin for neutron-induced fission studies. FIPPS is based on the combination of a large Germanium detector array surrounding a fission target, a Time-Of-Flight detector and a Gas-Filled Magnet (GFM) to identify mass, nuclear charge and kinetic energy of one of the fission fragments. The GFM will be instrumented with a Time-Projection Chamber (TPC) for individual 3D tracking of the fragments. A conceptual design study of the new spectrometer is presented.

After entering the blood, bisphosphonates are immediately bound to bone or excreted unchanged by the kidney. During renal excretion about 0.5% of administrated dosage remains in kidney tissue. The renal tissue level of bisphosphonates (RTL) decreases over time and remains at about 0.15% after 3weeks, but the influence of renal insufficiency (RI) is unclear.We investigated the influence of mild to moderate RI on RTL of ibandronate (IBD). First a method for determination of RTL was implemented and validated. We measured RTL in rats with normal renal function (SHAM) and after unilateral nephrectomy (UNX). In each case one SHAM and one UNX groups received one or alternatively 9 times every 3weeks a dosage of 1.5mg/kg IBD. After the last dosage the rats were sacrificed and RTL of IBD were determined.In SHAM-rats IBD concentrations increased from 272.7ng/g kidney after one injection to 428.9ng/g kidney after nine injections (p0.0001). RTL in UNX rats likewise increased significantly (p0.0001) from 289.9ng/g kidney to 520.2ng/g kidney.Our study found a 1.6 fold increase of RTL in SHAM rats and a 1.8 fold increase of RTL in UNX rats after nine versus one injection. As steady state is generally reached after five half-lives we anticipate no further accumulation on continued treatment.

International audience; Fission yields are essential for nuclear reactor studies (decay heat, fuel inventory…) and constitute also one of the main observables needed to improve our understanding of the fission process. The symmetric mass region is of particular interest due to various intriguing properties of the fission fragments already reported in the literature : inversion of the nuclear charge polarization, large width of the fission fragment kinetic energy distribution, strong change of the prompt neutron multiplicity, etc. Recently, measurements of fission yields and kinetic energy distributions in the symmetric mass region were achieved at the LOHENGRIN mass spectrometer of the Institut Laue-Langevin (ILL). This experimental work is challenging due to the low counting rate and the appearance of contaminant masses, leading to pronounced components in the fission fragment kinetic energy distribution. Despite removing the undesirable contributions, the fission fragment kinetic energy distributions still show two components, indicating that the fission process could be modal. To go further and better characterize these components a comparison between our experimental data and Monte Carlo calculations (FIFRELIN code) simulating the de-excitation of the fission fragments for different fission channels will be presented and discussed.

International audience; The accurate knowledge of the fission product properties of actinides is important for the studies of innovative nuclear fuel cycles and also for the understanding of the fission process. Until now fission models cannot predict the fission yields with an acceptable accuracy. A collaboration between LPSC (Laboratoire de PhysiqueSubatomique et de Cosmologie), ILL (Institut Laue-Langevin) and CEA (Commissariat à l’Energie Atomique et aux Energies Alternatives) is pursuing a measurement program performed at the LOHENGRIN spectrometer at ILL (Grenoble, France) that is dedicated to the thorough characterization of fission yields in mass A, nuclear charge Z, kinetic energy Ek and spin J. To assess this last quantity, so far only an indirect method through isomeric ratio measurements has been used at the LOHENGRIN spectrometer.Nevertheless the evaluation of the fission fragment spin distributions can be done also directly via the measurement of prompt neutron and γ spectra per isotope. The FIPPS (FIssion Product Prompt γ-ray Spectroscopy) project at ILL aims at combining a powerful γ ray detection array with a gas-filled recoil separator for one of the fission products. The combined spectrometer will give access to new nuclear spectroscopy information of neutron-rich nuclides by tagging the complementary fragment and new insight into the fission process via combined measurements of mass A, nuclear charge Z, kinetic energy Ek and excited states.To optimize the design of the gas-filled separator in terms of acceptance and resolving power, we performed preparatory experiments using the second dipole magnet of the LOHENGRIN fission fragment separator. Using mass and energy separated fission fragment beams we studied the transmission, energy acceptance, energy loss and resolving power in A and Z with helium and nitrogen gas filling at pressures ranging from 2 mbar to 40 mbar. For instance, with the given magnet properties the best separation was reached with He at pressures around 40 mbar, corresponding to an overall energy loss of 50% in the gas. In parallel we developed a Monte Carlo simulation code to reproduce the obtained results. This code is now used for the detailed design of the gas-filled separator of the FIPPS project. In this talk experimental and simulation results will be presented along with the current status of the FIPPS project.

International audience; The study of fission yields has a major impact on the characterization and understanding of the fission process and is mandatory for reactor applications. The LPSC in collaboration with ILL and CEA has developed a measurement program on fission fragment distributions at the Lohengrin spectrometer of the ILL, with a special focus on the masses constituting the heavy peak. We will present in this paper our measurement of the very low fission yields in the symmetry mass region and the heavy mass wing of the distribution for 233U thermal neutron induced fission. The difficulty due to the strong contamination by other masses with much higher yields will be addressed in the form of a new analysis method featuring the required contaminant correction. The apparition of structures in the kinetic energy distributions and possible interpretations will be discussed, such as a possible evidence of fission modes.

The characterisation of fragments from nuclear fission in terms of excitation energy and spin population is still a debated subject. We show that data on excitation energy, kinetic energy and spin of the fragments in thermal neutron induced fission of the actinides can be consistently described by the statistical model in nuclear physics. We present an empirical relationship which allows calculating the temperature of fission products at the scission point. From the temperature we derive the distribution functions for excitation, kinetic energy and fragment spin. We compare the results from the statistical model with experimental data from the LOHENGRIN spectrometer at the Institut Laue-Langevin in Grenoble/France.

communication - http://hal.in2p3.fr/in2p3-00797322; International audience; Analysis and results of the measurements of the independent isotopic and mass fission yieldsfor the 233U(nth,f) reaction are presented, which were performed at the Lohengrin recoil massspectrometer in ILL. The spectrometer separates the fission products according to their mass toion charge ratio and kinetic energy to ion charge ratio. Mass yields were obtained by means ofan ionisation chamber after separation by the spectrometer. Isotopic yields were determined byplacing two high-purity Germanium clover detectors downstream the spectrometer. An innovativeanalysis method developed for the Lohengrin spectrometer is presented, from which the final resultsare independent from the previous evaluations, which is usually not the case.

The LOHENGRIN fission fragment separator uses actinide targets in a neutron flux of about 5 × 10 14 neutrons / cm 2 / s in an in-pile position of the high-flux reactor of ILL Grenoble. For fission yield measurements relatively thin targets (tens of μ g / cm 2 ) are used, while for nuclear spectroscopy applications targets up to 1 mg / cm 2 are employed. This leads to fission rates up to 5 × 10 12 / s . The targets are heated by the fission power in vacuum to temperatures of up to 1000 ∘ C . The radiation damage caused by the fission fragments can reach 50 dpa (displacements per atom) per day, an extremely high value comparable to that caused by irradiation with intense heavy ion beams. Therefore the thick targets that were produced with different methods (painting, spray-painting, electrolysis and molecular plating) all suffer from a burnup that is much quicker than explainable by nuclear transmutation. We discuss physical effects responsible for this additional decrease in fission fragment rate and ways to improve the situation.

The $^{86}\mathrm{Se}$ nucleus has been investigated by $\ensuremath{\gamma}$-ray spectroscopy using an array of Ge detectors placed at the exit of the fission-fragment mass separator Lohengrin of the Institut Laue-Langevin. New transitions have been identified by studying the $\ensuremath{\beta}$ decay of $^{86}\mathrm{As}$. An excitation scheme is proposed and includes a ${2}_{2}{}^{+}$ level at 1399 keV and a possible ${3}^{+}$ level that are well reproduced by shell model calculations with the most recent parametrization. The properties of the excitations indicate a possible onset of $\ensuremath{\gamma}$ collectivity in $^{86}\mathrm{Se}$.

The objective of the present paper is to put in evidence the influence of damages due to the collision cascades which take place at the end of the heavy ion micrometer range, on the zirconium surface oxidation. A comparison between two zirconium oxidation experiments under heavy ion irradiation performed in the same temperature and pressure conditions is presented. In the first experiment, a 6 $\mu$m thick zirconium foil is irradiated with a 50 MeV $^{129}$Xe beam which stops in the Zr foil. In the second one, a 2 $\mu$m thick zirconium foil is crossed by the whole fission fragment distribution emitted in the $^{235}$U fission. In order to explain the unexpected increase of the oxidation rate observed in the first case, MeV argon irradiation experiments have been performed at IPNL. Results show that collision cascades created in the Zr foil, far from the surface, increase significantly the Zr oxidation.

In the framework of the Mini-INCA project, dedicated to the study of Minor Actinide transmutation process in high neutron fluxes, an α - and γ -spectroscopy station has been developed and installed at the High Flux Reactor of the Laue-Langevin Institut. This set-up allows short irradiations as well as long irradiations in a high quasi-thermal neutron flux and post-irradiation spectroscopy analysis. It is well suited to measure precisely, in reference to 59 Co cross-section, neutron capture cross-sections, for all the actinides, in the thermal energy region. The first measurements using this set-up were done on 243 Am and 242 Pu isotopes. Cross-section values, at E n = 0.025 eV , were found to be ( 81.8 ± 3.6 ) b for 243 Am and ( 22.5 ± 1.1 ) b for 242 Pu. These values differ from evaluated data libraries by a factor of 9% and 17%, respectively, but are compatible with the most recent measurements, validating by the way the experimental apparatus.

ACE; This paper is devoted to the study of the defect influence on uranium diffusion in zirconia in the context of nuclear waste disposal. The experiments in reactor conditions are performed at the Institut Laue Langevin in Grenoble using the Lohengrin spectrometer. A thin UO$_2$ layer in direct contact with a zirconium foil is irradiated in the ILL high-flux reactor. The fission product rate is around 3$\times10^{11}$ ions s^{−1}$ and the neutron flux is equal to 5$\times10^{14}$ n cm$^{−2}$ s$^{−1}$. The target temperature is controlled by an IR pyrometer and ranges from 470 to 490 \degresC. In these conditions, a zirconium oxidation is first observed before uranium diffusion. A model is proposed to deduce an apparent uranium diffusion coefficient in zirconia (ZrO$_2$) from the energy distribution broadening of a selected fission product (A=90). It is found to be equal to 10$^{−15} cm^2 s^{−1}$. The study of thermal diffusion is performed by using ion beam techniques (ion implantation and Rutherford Backscattering). ZrO$_2$ samples are implanted with 800 keV uranium ions at a dose of 10$^{16}$ ions cm$^{−2}$ and annealed at a pressure of 7.5$\times10^{−1}$ Pa. No uranium diffusion could be observed up to 800 \degresC. The influence of irradiation defects mainly due to fission products, both on zirconium oxidation and on uranium diffusion, is clearly demonstrated.

Isotopic yield measurements for thermal neutron induced fission of 245Cm at the Lohengrin fission-product mass separator are described. Using an ionisation chamber coupled to the Lohengrin mass separator and the stacked foil technique, we measured the isotopic yields from mass A=85 to mass A=115 (near symmetry region) corresponding to nuclear charges Z=33 (As) to Z=47 (Ag). This has considerably extended the data set previously known for the very light fission products providing isotopic yields from A=76 to 94. In the present work, the nuclear charge assignment was performed using the energy loss in a stack of foils of Parylene C, a technique developed and used previously. This allows 4 to 5 nuclear charges per mass to be measured. The global proton odd–even effect calculated from the present measurements is 9.3±0.5%, a value corresponding to the known systematics for the effect as a function of the Coulomb parameter. A study of the global proton odd–even effect as a function of the light fragment kinetic energy was additionally carried out and the intrinsic excitation energy at scission was deduced for different compound nuclei.

MINIBALL a highly efficient, position sensitive γ -spectrometer is under construction for upcoming radioactive-beam experiments. In contrast to high spin arrays the total full energy peak efficiency and not the resolving power is optimized with a factor of two larger efficiency for γ -ray energies up to 10 MeV and for low to medium γ -ray multiplicity events. Cluster detectors, incorporating three or four Ge crystals, will be employed to provide high flexibility and to accomodate the various demands of the experiments.

International audience; Within the EXILL campaign a large and efficient cluster of Ge-detectors was installed around a very well collimated neutron beam. This has allowed to carry out rather complete spectroscopic studies close to the line of stability using the (n,γ) reaction. Neutron rich isotopes were produced by neutron induced fission and prompt spectroscopy was carried out. The isotope selection in this setup was based on a partially known level scheme and the use of triple coincidences. The latter is limiting the statistical sensitivity in the case of weak production yields. Based on the experiences of these campaigns we are currently developing a new setup: FIPPS (FIssion Product Prompt Spectroscopy). This setup combines a collimated neutron beam, a highly efficient cluster of Ge detectors, a gas filled magnet and auxiliary detectors. The presence of the gas filled magnet will allow us to identify fission products directly and should give access to a new quality of studies if compared to the EXILL campaign. The EXILL campaign and the FIPPS project are presented.

An experimental study of the 241Am incineration in a high-intensity thermal neutron flux was carried out at the high-flux reactor of the Institut Laue-Langevin in Grenoble. The combination of nuclear γ -ray spectroscopy and off-line mass spectrometry methods made possible the measurement of several parameters of the transmutation chain and the first experimental determination of the unknown 242gsAm thermal neutron capture cross section, which plays an essential role in the 241Am incineration process. During a 19 days irradiation in a thermal neutron flux of 5.6×10 14 n /( s cm 2 ) , (46±5) % of the initial 241Am was transmuted by neutron capture of which (22±8) % was incinerated by nuclear fission. A value of the thermal neutron cross section of 242gsAm( n ,γ ) of (330±50) barns was obtained. We show that this keeps the option open to incinerate 241Am by high-intensity moderated neutron fluxes.

The mass-separator Lohengrin was used to measure the yields of the light fission products with A=74−85 and their nuclear charge and kinetic energy distributions from the odd- Z compound nucleus 239 Np ∗ formed by double capture of thermal neutrons. The mass yield distribution reveals an influence of the fragment shell with N=50 affecting also the nuclear charge and kinetic energy distributions. An odd–even effect for protons is found in the very asymmetric mass division, increasing from 4% to 35% with increasing fission asymmetry. This is in contrast to findings in normal asymmetric fission (region of high fission yields) where no odd–even effect for protons was observed. An odd–even effect for neutrons is also found comparable in size with that for protons. The latter effect exists also in normal asymmetric fission and is at least partly attributed to prompt neutron emission from the fragments. Some information on the number of prompt neutrons emitted is also obtained. From this information and from the energy dependence of the odd–even effect for protons it is concluded that the very light fragments originate from a cold and nearly undeformed light sphere of a dumbbell scission configuration characterised by a double shell closure with 28 protons and about 50 neutrons. In contrast to the double shell closure at mass 132 ( Z=50 , N≈82 ) the two shell closures in the light sphere do not coincide at one mass but are realised at A=70 and 80, respectively. This leads to a layered structure of the light sphere of the dumbbell scission configuration.

The main task in future low-energy nuclear science is now clearly visible. In recent years experiments have revealed that present nuclear models, which turned out to be so successful near the stability line, can probably not be directly transposed to regions of very neutron-rich isotopes. In particular in lighter nuclei strong deviations from the “standard” nuclear physics view appeared; lighter neutronrich species have been shown to possess neutron halos and neutron skins, features which are not known near the valley of stability [1]. The accumulation of neutrons on the nuclear surface is in turn thought to be responsible for the alteration of standard parameters used to calculate the properties of nuclei; depths of the central potential, spinorbit force, pairing [2]. These parameters are crucial for the calculation of the nucleus. They determine where magic shells are located and how strongly the nucleus is bound. Recent measurements have shown evidence for the disappearance of shell structure ...

Yields of light fission products (A = 68, 70-84, 87, 88, 94, 96, 98, 102 and 106-108), their kinetic energies and nuclear charge distributions (A = 71-84, 87 and 88) in the thermal neutron induced fission of the odd-Z nucleus Am-242m(Z = 95) were measured using the mass-separator Lohengrin at the Institute Laue-Langevin in Grenoble (France). The mass yield curve shows a fine structure at A = 70, probably due to shell and/or odd-even effects affecting also the nuclear charge distribution. The analysis of isotopic chain yields gives evidence for a very low excitation energy of the lightest fission fragments observed. A preferential formation of fragments with even Z is found for this odd-Z compound nucleus, Calculated values for the local odd-even effect are comparable with those for the neighbouring even-Z fissile nuclides and increase from 13% to 30% with increasing asymmetry of the mass split (A(L) = 84 to 68 and Z(L) = 35 to 28). The neutron odd-even effect shows a similar but less pronounced behaviour. (C) 1999 Elsevier Science B.V. All rights reserved.

Several $\ensuremath{\mu}\mathrm{s}$ isomers were observed in neutron-rich nuclei in the mass range $A=88--109.$ These nuclei are produced by thermal neutron-induced fission of ${}^{241}\mathrm{Pu}.$ The detection is based on time correlation between fission fragments selected by the LOHENGRIN spectrometer, at ILL (Grenoble) and the $\ensuremath{\gamma}$-ray or conversion electron emission of the isomers. Among a dozen isomers studied, three new ones have been observed. The decay schemes of ${}^{88m}\mathrm{Br},$ ${}^{94m}\mathrm{Y},$ ${}^{96m}\mathrm{Rb},$ and ${}^{100m}\mathrm{Nb}$ are discussed in the framework of the spherical shell model. The yields and isomeric ratios of all these isomers have been measured.

SUMMARYAutoantibodies to CRP were reported previously in patients suffering from toxic oil syndrome. This syndrome resembles autoimmune diseases such as systemic lupus erythematosus (SLE) or systemic scleroderma. We therefore examined the prevalence of antibodies to CRP and other acute-phase proteins in autoimmune diseases, including SLE, subacute cutaneous lupus erythematosus (SCLE), systemic scleroderma (SSc), and primary biliary cirrhosis (PBC), as well as in bone marrow transplantation-induced chronic graft-versus-host disease and eosinophilia–myalgia syndrome. IgG antibodies to CRP were found in 78% of SLE and in 30% of SCLE patients, while 16% of patients with PBC were positive. In up to 45% of patients with SSc predominantly IgG antibodies to ceruloplasmin were detectable. Lack of systemic involvement as in discoid lupus erythematosus and localized scleroderma (morphea) correlated with low or absent antibody formation. However, no correlation was found between anti-acute-phase protein antibodies with liver disease or other organ involvement. Adsorption studies revealed that non-native epitopes on the CRP molecule, termed modified CRP, are the main target of antibodies. Chronic inflammatory tissue injury in systemic autoimmune disease might increase the presentation of cryptic epitopes of CRP to the threshold required for T cell activation.

Cold binary fission has been studied in the spontaneous decay of252Cf (sf). Cold fission for the mass split 132/120 is especially interesting because here it is the doubly magic132 Sn which is dominating the yield for a range of total excitation energies 0 ≤ TXE ≤10MeV For the reaction242Am(n,f) induced by thermal neutrons the yields of the heaviest clusters being emitted as ternary particles have been investigated at the mass spectrometer Lohengrin of the Institut Laue-Langevin. The emission of the heaviest clusters (33, 34, 35 Si) is a cold process with all three reaction partners being born in or very close to their ground states.

On September 2, 1994, a m bLg 3.4 (USGS) earthquake occurred in central Michigan at 21:23:10 UTC. Relocation of the epicenter utilizing regional arrivals and consideration of macroseismic effects yields an epicenter of 42.57 ± 0.05°N, 84.64 ± 0.04°W. The focal depth is shallow, 10–15 km based on macroseismic effects. The felt area extended from Owosso and Portland in the north to south of Bellevue. Detailed macroseismic observations were obtained through requests in the local media and spot surveys in selected portions of the region; a maximum MM intensity of V was obtained in a band between Potterville and Eaton Rapids. The greater Lansing area was intensity III–IV, with elevated intensities along the Grand River and on glacial moraines. The limits of the isoseismal map of the event may be controlled in part by the population density in the region and the area covered by the local media. Many observers reported two shocks. The cause of the event remains undetermined, but may be due to a hypothetical northwest-striking basement fault associated with the Lucas-Monroe fault. In this event, left-lateral strike-slip motion is likely.

Two Radioactive Ion Beam facilities are projected at high-flux reactors: PIAFE at the Institut Laue Langevin in Grenoble and the Munich Fission Fragment Accelerator at the FRM-II in Garching. Both will operate with a “nuclear heated” target-ion-source assembly (fission rate ≈ 1014 S−1) in an in-pile position in a neutron flux of the order 1014 cm−2 s−1. The expected beam intensities are several orders of magnitude higher than those of existing ISOL facilities which use thermal neutron-induced fission. The major difference between the in-pile parts of the projects is the type of beam tube: PIAFE will use a single-ended tube where target change and ion extraction are done to the same side — at the FRM-II a tube with access from both sides will be used, allowing a spatial decoupling of target handling and ion extraction. Different methods to master the new technical challenges arising from the high neutron flux are discussed.

Seit Einfuhrung der laparoskopischen Cholezystektomie als Standardverfahren bei der symtomatischen Cholelithiasis wird der Wert der intraoperativen Cholangiographie kontrovers diskutiert. Anhand der eigenen Erfahrungen bei 2105 Patienten weisen wir nach, das durch die routinemasige intraoperative Cholangiographie sowohl die Rate der «stummen» Gallengangsteine als auch die der schweren Choledochuslasionen gesenkt werden kann.

The spectroscopy of the prompt gamma decay from fission products gives information on the entry states, e.g. distribution functions for excitation energy and spin, and therefore a direct link to the fission process itself. This type of spectroscopy is, however, only possible when a filter can be constructed which allows setting a gate to the gamma-spectrum in a narrow region in mass and nuclear charge, as well as on the total excitation energy of the fragment split under investigation. A possible configuration of a prompt gamma-ray spectrometer consist of a gamma-ray array composed of high resolution germanium detectors, coupled to a gas filled magnet. We will outline the principles for a gas filled magnetic spectrometer for fission product spectroscopy. In particular the focusing characteristics of such a device, which are valid for particles in the velocity regime of E/A< 1MeV/amu, will be addressed. First experiments on the LOHENGRIN spectrometer in Grenoble investigating on the behavior of fission products in gas filled magnets have been performed, and have validated the experimental approach to the nuclear fission process with such a device. Much work has been done over the last 75 years to measure observables in nuclear fission, mostly fission product mass, nuclear charge, and kinetic energy. The distributions of these observables are strongly dependent on mass and charge of the fissioning compound system, and the excitation energy which is given to the system to induce the fission process. Accessible are mostly secondary fission product distributions, after the emission of prompt neutrons and gamma rays. Standard measurements of mass and kinetic energy are done by measuring the kinetic energy of both fragments with the help of ionisation chambers or surface barrier detectors. By the measurement of the ratio of the two kinetic energies, and the assumption that both fragment masses add up to the compound nucleus mass, a rough idea of the mass distribution can be obtained, as well as a rough idea about the total kinetic energies by doing assumptions on the neutron evaporation process. A step further to obtain distribution functions for fission products is the combined measurement of the two velocities and the two kinetic energies of both fission products, which allows the reconstruction of the primary quantities of mass and total

communication - http://hal.in2p3.fr/in2p3-00797284; International audience; The Lohengrin mass spectrometer is one of the 40 instruments built around the reactor of the Institute Laue-Langevin (France) which delivers a very intense thermal neutron flux. Usually, Lohengrin was combined with a high-resolution ionization chamber in order to obtain good nuclear charge discrimination within a mass line, yielding an accurate isotopic yield determination. Unfortunately, this experimental procedure can only be applied for fission products with a nuclear charge less than about 42, i.e. in the light fission fragment region. Since 2008, a large collaboration has started with the aim of studying various fission aspects, mainly in the heavy fragment region. For that, a new experimental setup which allows isotopic identification by γ-ray spectrometry has been developed and validated. This technique was applied on the 239Pu(nth,f) reaction where about 65 fission product yields were measured with an uncertainty that has been reduced on average by a factor of 2 compared with what was that previously available in nuclear data libraries. The same γ-ray spectrometric technique is currently being applied to the study of the 233U(nth,f) reaction. Our aim is to deduce charge and mass distributions of the fission products and to complete the experimental data that exist mainly for light fission fragments. The measurement of 41 mass yields from the 241Am(2nth,f) reaction has been also performed. In addition to these activities on fission yield measurements, various new nanosecond isomers were discovered. Their presence can be revealed from a strong deformed ionic charge distribution compared to a 'normal' Gaussian shape. Finally, a new neutron long-counter detector designed to have a detection efficiency independent of the detected neutron energy has been built. Combining this neutron device with a Germanium detector and a beta-ray detector array allowed us to measure the beta-delayed neutron emission probability Pn of some important fission products for reactor applications.

Chronic graft-versus-host disease after bone marrow transplantation presents, in a few cases, as mild to severe scleroderma-like changes. Patients with chronic graft-versus-host disease with and without sclerodermatous skin changes were analysed for antinuclear autoantibodies (ANA) and antinucleolar autoantibodies (ANoA) and the results correlated with disease symptoms and histocompatibility locus antigen (HLA) pattern. Nineteen patients with chronic graft-versus-host disease and scleroderma-like skin changes, 18 with chronic graft-versus-host disease without scleroderma, and 17 controls on immunosuppressive treatment were screened for ANA and ANoA using enzyme-linked immunosorbent assay, immunodiffusion and immunoblot techniques. Four patients with severe scleroderma had antibodies to topoisomerase I, two had antibodies against PM-Scl, both characteristic serological findings in idiopathic systemic scleroderma. One patient had La/SSB antibodies and, in three cases, antibodies to the nucleolar antigen C23 (nucleolin) could be identified. A possible correlation between antinucleolin antibodies and disease activity was observed. HLA-A1, -B1, and -B2 were found significantly more often in patients with scleroderma-like symptoms in comparison to patients without scleroderma-like symptoms. Chronic graft-versus-host disease with scleroderma-like manifestations can be associated with the occurrence of ANA specific for idiopathic scleroderma. The development of scleroderma after bone marrow transplantation might have a HLA-linked genetic background.

International audience; The modelling of γ heating and neutron damage inside a nuclear reactor is essential to design the next generation of nuclear reactors. The determination of the fission fragment momentum is a key element to perform accurate calculations of the γ heating. One way to assess this information is to look at the isomeric ratio of different nuclei. According to the lifetime of the isomeric state, different experimental techniques were developed at the LOHENGRIN spectrometer. A focus on the measurement of isomeric ratios of 136I in neutron induced fission of 241Pu is presented. A discussion with the current assumptions used in the evaluation process for isomeric ratio is also shown.

The accurate knowledge of the fission of actinides is necessary for studies of innovative nuclear reactor concepts. The fission yields have a direct influence on the evaluation of the fuel inventory or the reactor residual power after shutdown. A collaboration between the ILL, LPSC and CEA has developed a measurement program on fission fragment distributions at ILL in order to measure the isotopic and isomeric yields. The method is illustrated using the 233 U(n,f) 98 Y reaction. However, the extracted beam from the Lohengrin spectrometer is not isobaric ions which limits the low yield measurements. Presently, the coupling of the Lohengrin spectrometer with a Gas Filled Magnet (GFM) is studied at the ILL in order to define and validate the enhanced purification of the extracted beam. This work will present the results of the spectrometer characterisation, along with a comparison with a dedicated Monte Carlo simulation especially developed for this purpose.