Directeur de recherche CNRS
Groupes :
Interactions fondamentales et nature du neutrino
Théorie et phénoménologie
+33 2 31 45 29 69
PUBLICATIONS
Measurement of the Double Beta Decay Half-life of 130Te with the NEMO-3 Detector
10 mai 2011
This Letter reports results from the NEMO-3 experiment based on an exposure of 1275 days with 661g of 130Te in the form of enriched and natural tellurium foils. With this data set the double beta decay rate of 130Te is found to be non-zero with a significance of 7.7 standard deviations and the (...)
Measurement of the beta-nu correlation coefficient a(beta nu) in the beta decay of trapped He-6(+) ions
30 mars 2011
We have measured the β-ν angular correlation in the β decay of 6He+ ions using a transparent Paul trap. The 6He+ ions, produced at GANIL, were first cooled and bunched before being injected in the LPCTrap setup. The angular correlation was inferred from the time of flight of recoil nuclei detected (...)
Probing New Physics Models of Neutrinoless Double Beta Decay with SuperNEMO
3 décembre 2010
The possibility to probe new physics scenarios of light Majorana neutrino exchange and right-handed currents at the planned next generation neutrinoless double beta decay experiment SuperNEMO is discussed. Its ability to study different isotopes and track the outgoing electrons provides the (...)
Measurement of the double-β decay half-life of 150Nd and search for neutrinoless decay modes with the NEMO-3 detector
30 août 2010
The half-life for double-β decay of 150Nd has been measured by the NEMO-3 experiment at the Modane Underground Laboratory. Using 924.7 days of data recorded with 36.55 g of 150Nd, we measured the half-life for 2νββ decay to be T 2ν 1/2 = (9.11+0.25 −0.22(stat.) ± 0.63(syst.)) × 1018 yr. The observed (...)
Measurement of the two neutrino double beta decay half-life of Zr-96 with the NEMO-3 detector
30 août 2010
Using 9.4 g of 96Zr isotope and 1221 days of data from the NEMO-3 detector corresponding to 0.031 kg y, the obtained 2νββ decay half-life measurement is View the MathML source. Different characteristics of the final state electrons have been studied, such as the energy sum, individual electron (...)
Results of the BiPo-1 prototype for radiopurity measurements for the SuperNEMO double beta decay source foils
27 juillet 2010
The development of BiPo detectors is dedicated to the measurement of extremely high radiopurity in $^208$Tl and $^214$Bi for the SuperNEMO double beta decay source foils. A modular prototype, called BiPo-1, with 0.8 $m^2$ of sensitive surface area, has been running in the Modane Underground (...)
A study of stopping power in nuclear reactions at intermediate energies
10 mars 2010
We show a systematic experimental study based on INDRA data of the stopping power in central symmetric nuclear reactions. Total mass of the systems goes from 80 to 400 nucleons while the incident energy range is from 12 AMeV to 100 AMeV. The role of isospin diffusion at 32 and 45 MeV/nucleon (...)
Isospin diffusion in 58Ni-induced reactions at intermediate energies
4 mars 2010
Isospin diffusion is probed as a function of the dissipated energy by studying two systems $^58$Ni+$^58$Ni and $^58$Ni+$^197$Au, over the incident energy range 52-74\AM. Experimental data are compared with the results of a microscopic transport model with two different parameterizations of the (...)
Measurement of the background in the NEMO 3 double beta decay experiment
24 avril 2009
In the double beta decay experiment NEMO 3 a precise knowledge of the background in the signal region is of outstanding importance. This article presents the methods used in NEMO 3 to evaluate the backgrounds resulting from most if not all possible origins. It also illustrates the power of the (...)
Isospin diffusion in semi-peripheral $^58Ni$+$^197Au$ collisions at intermediate energies (I) : Experimental results
15 décembre 2008
Isospin diffusion in semi-peripheral collisions is probed as a function of the dissipated energy by studying two systems $^58Ni$+$^58Ni$ and $^58Ni$+$^197Au$, over the incident energy range 52-74\AM. A close examination of the multiplicities of light products in the forward part of phase space (...)
Paul trapping of radioactive $^6$He+ ions and direct observation of their beta-decay
17 octobre 2008
We demonstrate that abundant quantities of short-lived beta unstable ions can be trapped in a novel transparent Paul trap and that their decay products can directly be detected in coincidence. Low energy 6He+ (807 ms half-life) ions were extracted from the SPIRAL source at GANIL, then (...)
Source shape determination with directional fragment-fragment velocity correlations
12 novembre 2007
Correlation functions, constructed from directional projections of the relative velocities of fragments, are used to determine the shape of the breakup volume in coordinate space. For central collisions of 129Xe + natSn at 50 MeV per nucleon incident energy, measured with the 4pi multi-detector (...)
Production of complex particles in low energy spollation and in fragmentation reactions by in-medium random clusterization
2 juillet 2007
Rules for in-medium complex particle production in nuclear reactions are proposed. These rules have been implemented in two models to simulate nucleon-nucleus and nucleus-nucleus reactions around the Fermi energy. Our work emphasizes the effect of randomness in cluster formation, the importance (...)
New approach of fragment charge correlations in $^129$Xe+$^nat$Sn central collisions
20 mars 2007
A previous analysis of the charge (Z) correlations in the $\Delta Z-$ plane for Xe+Sn central collisions at 32 MeV/u has shown an enhancement in the production of equally sized fragments (low $\Delta Z$) which was interpreted as an evidence for spinodal decomposition. However the signal is weak (...)
Universal fluctuations : a new approach to the study of phase transitions in intermediate energy heavy ion collisions
15 janvier 2007
The universal theory of order parameter fluctuations (D-scaling laws) is applied to a wide range of intermediate energy heavy-ion collision data obtained with INDRA. This systematic study confirms that the observed fragment production is compatible with aggregation scenarios for in- or (...)
Evaluation of excitation energy and spin from light charged particles multiplicities in heavy-ion collisions
5 janvier 2007
A simple procedure for evaluating the excitation energy and the spin transfer in heavy-ion dissipative collisions is proposed. It is based on a prediction of the GEMINI evaporation code : for a nucleus with a given excitation energy, the average number of emitted protons decreases with (...)
Effect of the intermediate velocity emissions on the quasi-projectile properties for the Ar + Ni system at 95 A.MeV
4 janvier 2007
The quasi-projectile (QP) properties are investigated in the Ar+Ni collisions at 95 A.MeV taking into account the intermediate velocity emission. Indeed, in this reaction, between 52 and 95 A.MeV bombarding energies, the number of particles emitted in the intermediate velocity region is related (...)
Comparisons of statistical multifragmentation and evaporation models for heavy-ion collisions
6 décembre 2006
The results from ten statistical multifragmentation models have been compared with each other using selected experimental observables. Even though details in any single observable may differ, the general trends among models are similar. Thus, these models and similar ones are very good in (...)
Spallation Neutron Production by 0.8, 1.2 and 1.6 GeV Protons on various Targets
31 octobre 2006
Spallation neutron production in proton induced reactions on Al, Fe, Zr, W, Pb and Th targets at 1.2 GeV and on Fe and Pb at 0.8, and 1.6 GeV measured at the SATURNE accelerator in Saclay is reported. The experimental double-differential cross-sections are compared with calculations performed (...)
Transition from participant to spectator fragmentation in Au+Au reaction between 60 AMeV and 150 AMeV
10 juillet 2006
Using the quantum molecular dynamics approach, we analyze the results of the recent INDRA Au+Au experiments at GSI in the energy range between 60 AMeV and 150 AMeV. It turns out that in this energy region the transition toward a participant-spectator scenario takes place. The large Au+Au system (...)
Multifragmentation of a very heavy nuclear system (I) : selection of a single-source events
10 juillet 2006
A sample of `single-source’ events, compatible with the multifragmentation of very heavy fused systems, are isolated among well-measured $^155$Gd+$^nat$U 36AMeV reactions by examining the evolution of the kinematics of fragments with Z>=5 as a function of the dissipated energy and loss of (...)
Multifragmentation of a very heavy nuclear system (II) bulk properties and spinodal decomposition
10 juillet 2006
The properties of fragments and light charged particles emitted in multifragmentation of single sources formed in central 36AMeV Gd+U collisions are reviewed. Most of the products are isotropically distributed in the reaction c.m. Fragment kinetic energies reveal the onset of radial collective (...)
Universal fluctuations in heavy-ion collisions in the Fermi energy domain
7 juillet 2006
We discuss the scaling laws of both the charged fragments multiplicity fluctuations and the charge of the largest fragment fluctuations for Xe+Sn collisions in the range of bombarding energies between 25 MeV/A and 50 MeV/A. We show close to E_lab=32 MeV/A the transition in the fluctuation (...)
Response of CsI(Tl) scintillators over a large range in energy and atomic number of ions (Part I) : recombination and $delta$-electrons
7 juillet 2006
A simple formalism describing the light response of CsI(Tl) to heavy ions, which quantifies the luminescence and the quenching in terms of the competition between radiative transitions following the carrier trapping at the Tl activator sites and the electron-hole recombination, is proposed. The (...)
Characteristics of the fragments produced in central collisions of $^129$Xe+$^nat$Sn from 32A to 50A MeV
7 juillet 2006
Transport and cooling of singly-charged noble gas ion beams
27 octobre 2005
The transport and cooling of noble gas singly-charged ion beams by means of a Radio Frequency Quadrupole Cooler Buncher (RFQCB) have been studied at the LIMBE low energy beam line of the GANIL facility. Ions as light as $^4He^+$ have been cooled and stored before their extraction in bunches (...)
Estimate of average freeze-out volume in multifragmentation events
5 septembre 2005
An estimate of the average freeze-out volume for multifragmentation events is presented. Values of volumes are obtained by means of a simulation using the experimental charged product partitions measured by the 4pi multidetector INDRA for 129Xe central collisions on Sn at 32 AMeV incident (...)
Evolution of Fragment Distributions and Reaction Mechanisms for the Ar+Ni System from 32 to 95 A.MeV
24 juin 2005
Within the framework of flow and multifragmentation study, the 36Ar+58Ni experiment has been performed at seven incident energies from 32 to 95 A.MeV with the INDRA detector at GANIL. After a brief description of the experimental set-up, the main trends as well as the evolution of fragment (...)
First applications of the HIPSE event generator
24 mars 2005
The predictions of an event generator, HIPSE (Heavy-Ion Phase-Space Exploration), dedi- cated to the description of nuclear collisions in the intermediate energy range, are compared with experimental data collected by the INDRA and INDRA-ALADIN collaborations. Spe- cial emphasis is put on the (...)
Macroscopic / microscopic simulation of nuclear reactions at intermediate energies
24 mars 2005
An event generator, HIPSE (Heavy-Ion Phase-Space Exploration), dedicated to the descrip- tion of nuclear collisions in the intermediate energy range is presented. The model simulates events for reactions close to the fusion barrier (5-10 MeV/A) up to higher energy (100 MeV/A) and it gives (...)
A study of nuclear stopping in central symmetric nuclear collisions at intermediate energies
14 mars 2005
Nuclear stopping has been investigated in central symmetric nuclear collisions at intermediate energies. Firstly, it is found that the isotropy ratio, Riso, reaches a minimum near the Fermi energy and saturates or slowly increases depending on the mass of the system as the beam energy (...)
Isotopic Scaling and the Symmetry Energy in Spectator Fragmentation
17 février 2005
Isotopic effects in the fragmentation of excited target residues following collisions of $^12$C on $^112,124$Sn at incident energies of 300 and 600 MeV per nucleon were studied with the INDRA 4$\pi$ detector. The measured yield ratios for light particles and fragments with atomic number $Z (...)
Directed and elliptic flow in $^197$Au+$^197$Au at intermediate energies
11 février 2005
Directed and elliptic flow for the Au + Au system at incident energies between 40 and 150 MeV per nucleon has been measured using the INDRA 4 pi multi-detector. For semi-central collisions, the elliptic flow of Z <= 2 particles switches from in-plane to out-of-plane enhancement at around (...)
Multiplicity correlations of intermediate-mass fragments with pions and fast protons in $^12$C + $^197$Au
3 novembre 2004
Model-independent tracking of criticality signals in nuclear multifragmentation data
6 septembre 2004
We look for signals of criticality in multifragment production in heavy-ion collisions using model-independent universal fluctuations theory. The phenomenon is studied as a function of system size, bombarding energy, and impact parameter in a wide range of INDRA data. For very central (...)
Intranuclear cascade+percolation+evaporation model applied to the $^12$C+$^197$Au system at 1 GeV/nucleon
16 avril 2004
Statistical multifragmentation of non-spherical expanding sources in central heavy-ion collisions
15 mars 2004
Fragmentation in peripheral heavy-ion collisions : from neck emission to spectator decays
22 juillet 2003
Transverse velocity scaling in $^197$Au+$^197$Au fragmentation
25 février 2003
Invariant transverse-velocity spectra of intermediate-mass fragments were measured with the 4-pi multi-detector system INDRA for collisions of Au on Au at incident energies between 40 and 150 MeV per nucleon. Their scaling properties as a function of incident energy and atomic number Z are used (...)
Multifragmentation process for different mass asymmetry in the entrance channel around the fermi energy
30 septembre 2002
Towards an unambiguous determination of the excitation energy of the projectile in heavy-ion reactions ?
11 juin 2002
Study of the dissipative binary channels in the $^107$Ag + $^58$Ni reaction at 52 MeV/nucleon
11 juin 2002
