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The K + −nucleus cross sections have been calculated in relativistic non-linear models taking into account the in-medium modifications of nucleons and mesons properties. More precisely, we have taken into account both the dressing of the nucleon effective mass by the scalar nuclear field in the target and the coupling of the mesons exchanged between the K + and the nucleons to the polarization of the medium. First, using the most recent relativistic non-linear models, the in-medium σ , ω and ρ meson masses have been obtained in the nuclear matter rest frame. The influence of the non-linear contributions on the K + −nucleus cross sections has then been studied. Finally, we have compared our results with the experimental data.

The accelerator based ion beam analysis method of proton induced X-ray emission (PIXE) has been used for analysing up to 14 elements in the blood serum of patients, collected from rehabilitation centres for the mentally retarded and from Medical College Hospital, Coimbatore, Tamil Nadu, India. The experimental subjects of the different groups displayed significant variations in their levels of certain trace elements such as zinc, iron, copper, phosphorus, chlorine, and rubidium. The results are compared with those of healthy control subjects and are discussed in detail in this paper. Hence, PIXE as a method of trace element analysis can be used to determine trace element content in mentally challenged patients.

The Landau parameters have been calculated in relativistic nonlinear models, on the one hand from the second derivative of the total energy density with respect to the quasinucleon distribution, on the other from the longitudinal dielectric function in relativistic RPA with and without the Pauli blocking terms in the polarization operators. The links between the Landau parameters and the collective modes obtained in the space-like region have been discussed.

A single event facility is currently under development at CENBG for applications in radiation biology. The aim is to induce the response of living cells by hitting selected individual specimens or specific sub-cellular compartments with an exact number of light ions. In order to avoid the construction of a complete beam line, it was decided to adapt the existing microprobe system. The line has been equipped with a removable final irradiation stage constituting a versatile system working on demand either in external beam mode or classical analysis under vacuum. The beam blanking is ensured by particle detectors which have been specifically designed to control MeV proton or alpha beams in a single event mode. This paper presents the overall experimental setup and first in-air experimental tests.

In the two-beam accelerator scheme, a high-current electron beam, bunched at the resonant frequency, traverses extraction cavities, where it generates power intended to drive accelerating cavities on the main beam. Here, we report on work performed to test some aspects of this scheme. We used a free-electron-laser (FEL) amplifier at 35 GHz to bunch a beam of electrons, which is then transported and focused into a resonant cavity. The results of earlier bunching experiments had demonstrated the capacity of the FEL supplied by an induction linac to generate an appropriate drive beam. A summary of this earlier work is presented along with measurements of power from the cavity. This constitutes the first observation of high-frequency power extraction using a FEL in this scheme.

The nuclear microprobe (NMP) unit of the National Accelerator Centre (NAC) has initiated a focused research programme on studies of biological material, ranging from applications in medicine to agriculture and botany. During this period a state-of-the-art cryo-preparation laboratory was also developed. This research programme has resulted in a wide range of projects, and has shown how well suited the NMP is for studies of biological material in general. This paper reports on some of the problems and demands in this field, as well as some of the results obtained using particle induced X-ray spectroscopy (PIXE) and Rutherford backscattering (RBS). True elemental imaging is routinely performed using the dynamic analysis (DA) method, which forms part of the GeoPIXE suite of programmes. A collaborative project, together with the CENBG group of Bordeaux–Gradignan in France, on the development of a facility with the aim of studying effects of single-events of radiation in living cells was recently established and is discussed.

What constitutes an element? The ancient Greeks believed in four elements: earth, wind, fire and water. By the l920s, however, physicists were defining elements according to the number of protons within the atomic nucleus. Meanwhile, pioneering work by Frederick Soddy and Kasimir Fajans demonstrated the existence of different isotopes – atoms that have similar chemical properties but different masses. This work culminated in 1932 with James Chadwick's discovery of the neutron, the uncharged particle that effectively damps out the Coulomb repulsion between the charged protons.

In this paper, we report micro-PIXE analysis of normal human skin sections. The aim of this preliminary study was to investigate the tissue morphology using the distribution pattern of mineral ions. We found that these minerals were compartmentalized enough to constitute useful markers of the tissue ultrastructure. The epidermis and its different skin strata, corneum, granulosum and spinosum, were actually identified on elemental maps. The present work also provided additional useful information about minerals in the intradermal part of hair tracts. Methodological points will be evoked on the basis of this experience, more especially those concerning the sampling procedure.

In experiments at GANIL and GSI, we explored the proton drip line to search for new isotopes and to study the decay modes of nuclei close to the drip line. The study of -delayed proton emission of revealed a very nice agreement between theory and experiment. Studies at GSI enabled us to observe the new isotopes , , and , the latter one being the neighbouring isotope of the doubly-magic nucleus . Finally, at GANIL, the fragmentation of showed clear evidence for the new isotopes , , and . In addition, we performed half-life measurements on and nuclei in this mass region.

The density dependence of the MIT bag constant in nuclear matter has been determined self-consistently using some physical observables as input in a quark-meson coupling model. More precisely, for this calculation, a saturation curve of nuclear matter has been built in such a manner the empirical saturation point and compressibility are reproduced, and the real part of the Schrodinger-equivalent nucleon-nucleus optical potential at saturation density has been constrained to a realistic value. In addition, it has been required that the density dependence of the bag constant lead to a very small increase of the bag radius in nuclei in accordance to the electron-nucleus scattering data.

In an experiment at the LISE3 facility of GANIL, we used the projectile fragmentation of a 36 Ar primary beam at 95 MeV/nucleon to produce the isotope 24 Si. The beta decay half-life of 24 Si has been determined to be T 1/2 = (140 ± 8) ms, in agreement with earlier measurements. In addition to the decay of the isobaric analog state, several proton peaks are observed for the first time allowing to identify most of the Gamow-Teller transitions to unbound states and to present a partial decay scheme for 24 Si. These results are compared with shell-model predictions.

Pronounced electron-beam bunching and high-power emission at 3 GHz have been observed in the 35-GHz free-electron-laser (FEL) experiment at CEA/CESTA. It corresponds to the low-frequency resonance of the FEL which appears in addition to the high-frequency resonance when a waveguide is used. The dependence of the bunching on length (in the wiggler) and time (in the pulse) shows that the spontaneously generated low-frequency mode comes to dominate the high-frequency injected mode at long distances and late times.

An in-medium effective NN interaction has been determined using the relativistic Hartree approximation in which coupling constants have been made density-dependent. For this calculation a saturation curve of nuclear matter has been built in such a manner that the saturation point can be reproduced and the compressibility is able to change, ranging from the Walecka model value to the Dirac - Brueckner one. Using this density-dependent NN interaction, we have studied the influence of the compressibility of nuclear matter on some physical observables like the Schrodinger-equivalent nucleon - nucleus optical potential or the Coulomb sum.

Principles of a new EAS detector are discussed. It is based on the so-called TTC (time-track complementarity) method, which implies the simultaneous measurement of incidence angles and arrival times of EAS muons. By means of only these measurements and using a single muon detector, the `muon eye', it is possible in principle to locate the EAS axis. The method of such a location, necessary formulae and accuracy estimates are presented. The latter have been obtained by simulations. The duty cycle and the acceptance of just a single detector have been shown to be rather large. The possible advantage of using more `muon eyes' is discussed.

The epithelial cells of the human amniotic membrane have been extensively studied by electrophysiologists with the aim of elucidating the mechanisms of transmembrane ionic transfers. In order to provide complementary information about this model, nuclear microanalysis was performed using the CENBG ion microbeam. Quantitative mapping of the human amnion was carried out and the distributions of most mono- and divalent ions involved in cellular pathways (Na+, Mg2+, Cl−, Ca2+) were determined. The ionic cellular content was also compared, before and after incubation in a Hanks' physiological fluid and the resultant ions transfers were determined. The aim of this paper is to expose the advances of this experimental model, more particularly after the development of simulation programs which improved the accuracy of PIXE analysis in the measurement of low energy X-rays emitters. Statistically significant results can now be extracted and can be explained taking into account the results of previous electrophysiological experiments.

A computational algorithm, capable to simulate RBS spectra recorded during scanning proton microprobe analysis of organic specimens with inhomogeneous thickness has been developed. This program is based on an enhancement of the RUMP source code. It allows us to normalize in terms of dry specimen mass the elemental concentrations obtained with simultaneous PIXE and RBS microanalysis. This code includes non-Rutherford cross sections for proton scattering from carbon, nitrogen and oxygen. It permits the computation of matrix correction factors for the analysis of low energy X-ray emitters. In this paper, the first version of the simulation algorithm is presented as also the application to the analysis of reference organic material.

In the calculation of the $K^+$-nucleus cross sections, the coupling of the mesons exchanged between the $K^+$ and the target nucleons to the polarization of the Fermi and Dirac seas has been taken into account. This polarization has been calculated in the one-loop approximation but summed up to all orders (RPA approximation). For this calculation a density-dependent Brueckner-Hartree-Fock NN interaction providing a good description of both nuclear matter and finite nuclei has been used. The agreement with experiment is considerably improved.

At the projectile-fragment separator FRS of GSI, relativistic secondary beams of about 520 MeV/nucleon were produced by fragmentation of a primary beam of58Ni at 650 MeV/nucleon in a beryllium target. By means of aΔE—Bρ—TOF measurement, the fragments have been identified and their charge-changing probabilities in targets of CH2, C, Al, and Pb have been determined. We describe the results for the total charge-changing cross sections in this first paper, whereas a second article deals with the partial charge-changing cross sections. At the drip line, the measured charge-changing cross sections exhaust close to 100% of the total interaction cross sections as calculated with semiempirical models. The measurements at the proton drip line with low-Z targets indicate that only a very small increase of the cross sections may be observed, whereas the measurements with a lead target show that no significant increase of the total charge-changing cross sections is present which would be a hint for low-lying dipole strength. Our experimental data are compared to Glauber-type calculations.

The effect of taurine on the Na(+), K(+), Cl(-) concentration and distribution in epithelial and compact layers of the human amniotic membrane had been investigated using the Bordeaux nuclear microprobe. Particle induced X-ray emission and Rutherford backscattering spectrometry techniques had been used to provice quantitative measurements. In physiological medium, the monovalent ions concentrations were identical in epithelial and compact layers. The addition of taurine in Hanks' physiological fluid had no effect on Na(+) concentration, but decreased K(+) and Cl(-) concentration in both layers. The quantitative results were related to electrophysiological observations on the effect of taurine on ionic exchanges through channels and paracellular pathways.

Low-energy fission of neutron-deficient actinium, thorium, protactinium and uranium isotopes has been investigated using a new experimental technique. The isotopes were produced as secondary beams by projectile fragmentation from a 950 A MeV 238U primary beam. Their fission was induced by electromagnetic excitation and nuclear reactions in a lead and in a plastic target at energies between 510 A MeV and 150 A MeV. The transition from symmetric fission is shown to take place around N = 138.

A back-to-back ionisation chamber has been used to measure the fission fragment mass-kinetic-energy correlations for 248 Cm(s, f). In all about 12 × 10 6 fission events were collected. The different distributions in the high-yield region are consistent with the existent data. As predicted by the theory of fission channels, the existence of far-out asymmetric fission has been confirmed, but its amplitude is much smaller than that for 252 Cf(s, f) indicating that the barrier of the channel corresponding to this channel should be lower for 252 Cf(s, f) than for 248 Cm(s, f). Furthermore, the 〈 E K 〉( M H ) and σ E K ( M H ) distributions show correlated fluctuations in the far-out asymmetric region suggesting the existence of at least two scission configurations with different deformations for the same fragmentation. In the cold-fission region, the deformed neutron N ⋍ 88 shell dominates the yield.

We present a total of 427 np analyzing power data points in a large angular interval at 12 energies between 0.312 and 1.10 GeV. The SATURNE II polarized beam of free monochromatic neutrons was scattered either on the Saclay frozen-spin polarized proton target or on CH2 and C targets. Present results are compared with existing elastic and quasieleastic data.

The micro-PIXE technique has been regularly carried out for more than two years to provide elemental distributions in human cells. Using this technique in the framework of cellular biology, two research axes have been developed: the cellular pharmacology f chemotherapeutic agents and the physiology of ionic cellular exchanges. These studies are based upon in vitro experimental models of human cells, either under the form of isolated cultured cells or as part of well-structured tissues. The aim of this paper is to present the experimental procedures and methodological aspects of cellular and subcellular quantitative mapping. Cell processing, identification of intracellular structures, quantitatives results and beam damage will be discussed and illustrated by examples issuing from the above-mentioned studies.

Doubly differential cross sections for the double excitation of helium by high velocity protons are measured and compared with the predictions of the first-order Born approximation. Preliminary experimental data for the shapes and intensities of the resonances 2s2 1S, 2p2 1D and 2s2p 1P have been obtained from high resolution electron spectra at 20', 90' and 150' for a proton energy of 3 MeV. Both experiment and theory show that the excitation of the 1P resonance largely exceeds the 1D and 1S ones at this collision velocity. The shape and emission yield of the 1P line is well described by theory over the whole angular range. The agreement for the other two resonances is not always satisfactory.

Thin films of indium fluoride were obtained by sublimation under vacuum of high purity powders. Their crystallographic state and composition, as a function of the preparation conditions, were investigated by X-ray diffraction, Rutherford backscattering of α particles, mass spectrometry and photoelectron spectroscopy. The energy band gap of the obtained layers and their electrical characteristics were respectively deduced from optical absorption measurements and admittance spectroscopy.

Trajectory calculations for an alpha-particle inside and outside the fission nucleus236U were used to simulate the alpha-accompanied fission of the system235U+n. The model was developed in two dimensions and the energy conservation condition was fulfilled. It was possible in this way to describe the emission process qualitatively. It was also shown that the calculation of such internal trajectories represents a sensitive method to obtain information about the configuration of the neck region of a fissioning nucleus.

Dans une collision nucleaire, le processus de desexcitation par emission de particules est loin d'etre connu en ce qui concerne le nombre de nucleons reellement impliques dans la source, ou la collision, ainsi qu'en ce qui concerne l'echelle temporelle du phenomene. Pour determiner les caracteristiques de la source reelle, certaines experiences ont ete effectuees en utilisant des effets d'interferences provenant de l'indiscernabilite de corpuscules (nn, γγ, p-p, n-n). Une analogie entre la source de particules et une sorte d'etoile, dont la vie serait tres breve, la taille inconnue, et dont on mesurerait les dimensions par interferometrie comme en Astronomie a souvent ete evoquee. Les methodes qui mettent en jeu les principes d'indiscernabilite, presentent en effet certaines analogies avec les methodes de correlation, dites du second ordre, de processus incoherents (Optique, collisions atomiques). Nous passons en revue les divers aspects de ces methodes et examinons leurs liens eventuels.

International audience

The low background gamma spectroscopy has been applied to try to sign the geographical origin of the French atlantic marine salts and of the prunes from Agen. Most of the activity measurements have been done using low background Ge spectrometers located in Bordeaux. Results have shown that a clear signature exists in the case of the French atlantic salts using the $^{40}$K, $^{137}$Cs and $^{226}$Ra isotopes but not in the case of the prunes.

Most of the underground experiments in physics and many studies in geology, biology or environmental sciences face a common requirement with the necessity of using experimental devices with ultra-low background radioactivity. Many developments involving many different techniques have been used in order to be able to measure extremely low levels of radioactivity in materials. This report will focus on low background gamma ray spectrometry and will describe the work which has been carried out over the last fifteen years in the “Laboratoire Souterrain de Modane” (LSM).

The first data of the NEMO 3 neutrinoless double beta decay experiment have shown that the radon can be a non negligible component of the background. In order to reduce the radon level in the gas mixture, it has been necessary first to cover the NEMO 3 detector with an airtight tent and then to install a radon‐free air factory. With the use of sensitive radon detectors, the level of radon at the exit of the factory and inside the tent is continuously controlled. These radon levels are discussed within the NEMO 3 context.

International audience; L'existence annoncée de la radioactivité di-proton doit être confirmée expérimentalement au moyen d'un détecteur à ionisation. Les pré-amplificateurs généralement employés avec ce type de détecteur ont une plage de linéarité trop faible pour effectuer le traitement des signaux produits dans cette expérience. Un concept utilisant un convoyeur de courant de deuxième génération à sorties multiples permet de surseoir au besoin spécifique de mesurer des signaux de grande dynamique en amplitude. L'architecture du système de pré-amplification couplé au détecteur , ainsi que les caractéristiques du convoyeur de courant sont présentées dans cet article.

Expérience GANIL; International audience; Two-proton radioactivity was predicted more than 40 years ago. According to recent theoretical predictions, proton drip-line nuclei in the A=40–55 region were identified as the most promising candidates. The recent observation of two-proton radioactivity of 45Fe confirmed these predictions nicely. In the present paper, we will summarize experimental results for the decay of 45Fe, which include data from the 2002 discovery of this radcioactivity, but also new data. In addition, we will report on the first observation of 54Zn and its decay by two-proton radioactivity, the second case of this new decay mode. Finally, we will discuss tentative evidence for a small two-proton radioactivity branch for 48Ni. These experimental results are confronted to modern theories which succeed in describing reasonably well this decay mode.

Available online at http://www.jacow.org/; International audience; A simulation of the generation of Smith-Purcell (S-P) radiation at terahertz frequencies is performed using the two-dimensional particle-in-cell code MAGIC. The simulation supposes that a thin (but infinitely wide), mono-energetic electron beam passes over a diffraction grating. We simulate two configurations, one similar to the Dartmouth S-P FEL, with a low-energy continuous beam (we use an axial magnetic field to constrain the electrons to essentially one-dimensional motion). The other is similar to the recent MIT experiment that uses a pre-bunched 15 MeV beam.

International audience; For several years the only experiments sensitive to astrophysical gamma rays with energies beyond the reach of EGRET but below that the Cherenkov imaging telescopes have been the "solar towar" detectors. They use > 2000 m$^{2}$ mirror areas to sample the Cherenkov wavefront generated by

The recent WMAP data have confirmed that exotic dark matter together with the vacuum energy (cosmological constant) dominate in the flat Universe. Supersymmetry provides a natural dark matter candidate, the lightest supersymmetric particle (LSP). Thus the direct dark matter detection is central to particle physics and cosmology. Most of the research on this issue has hitherto focused on the detection of the recoiling nucleus. In this paper we study transitions to the excited states, focusing on the first excited state at 50 keV of Iodine A=127. We find that the transition rate to this excited state is about 10 percent of the transition to the ground state. So, in principle, the extra signature of the gammai ray following its de-excitation can be exploited experimentally., Comment: LaTex, 13 pages, 3 postscript figures, 1 table, to appear in IJMPE

We present a generalization of the Extended Thomas Fermi (ETF) theory to fermionic systems at finite temperature and finite angular momentum. In fact the present approach is more general in the sense that it is able to treat an excited system of fermions subject to an external vector field which in the case of nuclear rotations, developed more extensively here, is simply .

In the framework of studies concerning new fuel cycles and nuclear wastes produced by reactors, we have undertaken a number of measurements in order to determine the radiative capture and/or the fission cross sections of neutron induced reactions on several nuclei($^{232}$Th, $^{233}$Pa, $^{233}$U) which play an important role in the Th-U cycle as well as a study of the transmutation of the long lived fission residue $^{129}$I.

Energy and angular distributions of the fast outgoing electron beam induced by the interaction of 1-2 J, 30 fs, 3-20x10 18 W/cm 2 laser with a thin foil or a gas jet target are characterized by using both an electron spectrometer and Bremsstrahlung induced photo-nuclear reactions. The supra-thermic electron beams production was investigated for a solid target versus its thickness and its Z number, and for a gas jet target versus its pressure. Using a polyethylene target and a supersonic Helium gas jet target, we measured, respectively, up to 4x10 8 and 3x10 9 electrons produced per laser pulse, with energies up to, respectively, 60 MeV and 160 MeV. The associated Boltzmann temperature of these electrons is colder for thin foils (9 MeV) than for gas jet (18 MeV). About, respectively 0.06% and 1% of the laser energy has been converted to outgoing electrons with energies above 5 MeV. Such electrons leave the plasma in the laser direction within a cone with an opening angle of, respectively, 2.5° and 8.5°. We discuss the physical processes of electron acceleration. Numerical calculations show a good agreement with the experiments.

Available online at http://www.JACoW.org; International audience; Many years ago Fajans, Kirkpatrick and Bekefi (FKB) studied off-axis orbits in a realistic helical wiggler, both experimentally and theoretically. They found that as the distance from the axis of symmetry to the guiding center increased, both the mean axial velocity and the precession frequency of the guiding center varied. They proposed a clever semi-empirical model which yielded an excellent description of both these variations. We point out that a approximate model proposed by us several years ago can be made to predict these delicate effects correctly, provided we extend our truncated quadratic Hamiltonian to include appropriate cubic and quartic terms. We develop an argument similar to the virial theorem to compare time averaged and fixed-point values of dynamical variables. Illustrative comparisons of our model with numerical calculation are presented.

The proposed experiment SLAC E166 intends to generate circularly polarized gamma rays of energy 10 MeV by passing a 50 GeV electron beam through a meter long wiggler with approximately 400 periods. Using an analytic model formulated by Rullier and me, I present calculations of electron trajectories. At this extremely high energy the trajectories are described quite well by the model, and an extremely simple picture emerges, even for trajectories that that fail to encircle the axis of the wiggler. The calculations are successfully compared with standard numerical integration of the Lorentz force equations of motion. In addition, the calculation of the spectrum and angular distribution of the radiated photons is easily carried out.