[en] The aim of this work is to study the dynamics of swift multicharged ion-induced fragmentation of diatomic (CO) and triatomic (CO₂) molecules. Performed at the GANIL facility, this study used the Recoil Ion Momentum Spectroscopy technique (RIMS), which consists of a time-of-flight mass spectrometer, coupled with a multi-hit capability position sensitive detector (delay line anode). The high-resolution measurement of the kinetic energy distribution released (KER) during the CO fragmentation points out the limitation of the Coulomb Explosion Model, revealing, for example, the di-cation CO₂⁺ electronic state contribution in the case of C⁺/O⁺ fragmentation pathway. Furthermore, the multi-ionization cross section dependence with the orientation of the internuclear axis of CO is compared with a geometrical model calculation. Finally, different behaviours are observed for the dissociation dynamics of a triatomic molecule (CO₂). While triple ionization leads mainly to a synchronous concerted fragmentation dynamics, a weak fraction of dissociating molecule follows a sequential dynamics involving CO₂⁺ metastable states. In the case of double ionization, (CO₂)²⁺ di-cation dissociation dynamics is asynchronously concerted and has been interpreted using a simple model involving an asymmetrical vibration of the molecule. (author)

[en] We present a detailed study of the two collisional systems: He²⁺ (11 keV/u) and O⁷⁺ (4 keV/u) on CO molecule. We measured in coincidence the full momentum vector of the two fragments of the dissociated molecule and the projectile charge state. It is thus straightforward to access the dependence of the capture process on the angle between the beam and the internuclear axis of the molecule. The KER (kinetic energy release) distribution for each fragmentation channel is obtained for each outgoing projectile charge state associated to single capture, stabilized and autoionizing double capture,.. It has to be noted that, contrarily to ion-atom collisions, Auger decay of the target plays an important role: double capture by He²⁺ on CO may lead to four-fold ionization of the target. (orig.)

No abstract available

[en] First off-line tests at the ion trap facility SHIPTRAP took place. The facility is being set up to deliver very clean and cooled beams of singly-charged recoil ions (Rare Isotope Beam) produced at the SHIP (Separator for Heavy Ion Production) velocity filter at GSI, Darmstadt. SHIPTRAP consists of a gas cell for stopping and thermalizing high-energy recoil ions from SHIP, an rf ion guide for extraction of the ions from the gas cell, a linear rf trap for accumulation and bunching of the ions, and a Penning trap for isobaric purification. The physics programme of the SHIPTRAP facility comprises mass spectrometry, nuclear spectroscopy, laser spectroscopy and chemistry of transeinsteinium elements. The progress in testing the sub-systems separately and in combinations is reported.

[en] Complete text of publication follows. Ultra High Intensity lasers produce energetic particles such as electrons, protons, photons within a large domain of energies. In a range between a few MeV to few tens of MeV, these beams may open new opportunities to study nuclear isomer production in plasma in relation with astrophysical problems. Such studies require the knowledge of the particle energy and angular distributions to quantify possible future experiments. For this purpose, we have developed a standalone integrated data acquisition system to characterize proton and electron beams (converted into photons via bremsstrahlung) using nuclear activation techniques. This system called NATALIE (Nuclear Activation Technique for Analysis of Laser Induced Energetic particles) is composed of sixteen NaI detector pairs used to count the activity of various samples activated via (γ,xn) or (p,n) reactions for example. The setup is based on a coincident technique which allows β⁺ activity measurements with very low background and leads to accurate nuclear activation yields determination. Geant4 simulations are used at different steps of the data analysis to deduce the energy and angular distributions of the laser-induced particle beams from the experimental data. Two applications are presented as illustrations regarding the characterization of electron and proton beams. Acknowledgements. We acknowledge the support of IN2P3/Region Aquitane for a BDI grant (C.P.) and financial supports from ANR (contract no. ANR-07-JCJC-0158), Conseil Regional d'Aquitane (contract no. 200713040005) and IN2P3/CNRS.

[en] Full text: Ionization and excitation of H₂ or D₂ have been the subject of intensive studies during the last three decades. Very recently, experimental and theoretical works have been devoted to the analysis of the processes that are responsible to electron ejection after the impact of fast charged particles. In the case of 13.6 MeV / amu S¹⁵⁺ + D₂ collision, the ejection of an electron in coincidence with D⁺ fragments was analyzed by measuring both time of flight and position of the collision partners. From the resulting spectra, the different processes (ground state dissociation, ionization + excitation, autoionizing double excitation and double ionization) could be separated. In particular, autoionizing double excitation is found to be dominant for D⁺ and emitted electron energies in the range 0.7 eV - 3.5 eV and 5 eV - 15 eV, respectively. More detailed information for autoionizing double excitation could be obtained by measuring electrons in fast e^- + D₂ collisions. Superimposed on the ionisation spectrum, small structures centred at energies below 15 eV are clearly observed. This reproducible structure is attributed to double excitation (DE) of D₂. Subtraction of this ionization contribution leads to a DE spectrum, that could be compared to theoretical results. The structures observed in the experiment are also present in the calculated spectrum. The calculation shows that the contribution of Q₁ and Q₂ resonances, lying above the first and second ionization threshold, respectively, are dominant. The peak centred at energies larger than 10 eV results from interference between direct ionisation and autoionisation while the molecule dissociates. The dependence of the autoionized cross sections with the projectile velocity will be also presented at the conference

[en] The physics program of the SHIPTRAP facility comprises mass spectrometry, nuclear spectroscopy, optical spectroscopy, and chemistry of fusion reaction produced nuclides and, especially, transeinsteinium elements. One of the major limitations to the experimental investigations is the low production rate for exotic nuclei. Detection schemes based on a destructive time-of-flight measurement lead to intolerably long beam times. An alternative is the Fourier transform-ion cyclotron resonance (FT-ICR) technique. It is suited for ion identification and mass measurements as well as for chemical studies. (orig.)

[en] We present a stand-alone system to characterize the high-energy particles emitted in the interaction of ultrahigh intensity laser pulses with matter. According to the laser and target characteristics, electrons or protons are produced with energies higher than a few mega electron volts. Selected material samples can, therefore, be activated via nuclear reactions. A multidetector, named NATALIE, has been developed to count the β⁺ activity of these irradiated samples. The coincidence technique used, designed in an integrated system, results in very low background in the data, which is required for low activity measurements. It, therefore, allows a good precision on the nuclear activation yields of the produced radionuclides. The system allows high counting rates and online correction of the dead time. It also provides, online, a quick control of the experiment. Geant4 simulations are used at different steps of the data analysis to deduce, from the measured activities, the energy and angular distributions of the laser-induced particle beams. Two applications are presented to illustrate the characterization of electrons and protons.

[en] First off-line tests at the ion trap facility SHIPTRAP took place. The facility is being set up to deliver very clean and cooled beams of singly-charged recoil ions produced at the SHIP velocity filter at GSI, Darmstadt, SHIPTRAP consists of a gas cell for stopping and thermalizing high-energy recoil ions from SHIP, an rf ion guide for extraction of the ions from the gas cell, a linear rf trap for accumulation and bunching of the ions, and a Penning trap for isobaric purification. The physics program of the SHIPTRAP facility comprises mass spectrometry, nuclear spectroscopy, laser spectroscopy and chemistry of transeinsteinium elements. The progress in testing the subsystems separately and in combinations is reported

No abstract available