ANNUAL REPORT 2011 - Instituto de Estructura de la Materia

ooooooooooooooooooooooReaction studies at low energy at the 5MV accelerator CMAM@UAM.Reaction studies at relativistic energies, the R3B experiment at GSI.GEANT4 Monte Carlo simulation of experimental set-up and detectors.Electronic and mechanical design of experimental set-up.Mathematics and computing methods.Analysis pf experiments in experimental nuclear physics.Numerical simulation.Computational methods.Neutron scattering.Calorimetric techniques.Absorption techniques.IR Spectroscopy (Normal, FTIR, and SEIR).Raman Spectroscopy (normal, micro-Raman, Raman mapping, Raman imaging and SERS).Visible-UV Spectroscopy.IR and Raman Spectroscopy of twodimensional correlation by H/D isotopic exchange.Optical Emission Spectroscopy (OES).Fluorescence Spectroscopy.Transmission and Scanning Electron Microscopy (TEM, SEM).Multivariate statistical analysis.Theoretical Physics (Classical Electrodynamics) and numerical calculations.Laser Induced Fluorescence (LIF).Laser Physical Deposition (LPD).RESEARCH ACTIVITY:CHARACTERIZATION OF NUCLEAR STATES RELEVANT IN STELLAR NUCLEAR-SYNTHESISPROCESSESAlong the years we have developed techniques that allow us to go deeply into the decay modes of exotic nuclei, andespecially to learn about the breakup of unbound states and determination of the reaction rate for reaction ofastrophysical relevance. In previous years we informed about the study in full kinematics of the 3-alpha breakup ofthe levels of 12 C-populated in the β + -decay of 12 N and β - -decay of 12 B. As the study of the breakup of the low energylevels of 9 Be is relevant to the 4 He(n,) 9 Be reaction rate. This reaction is an alternative to the triple-alpha fusion inneutron-rich stellar scenarios. Complementary to this work we have studied the reaction 10 B+ 3 He whose channelsthrough states in 12 C and 9 B provide information on excited states not accessible to the beta decay thus a completepicture of the structure of these nuclei can be obtained. This work is based on experiments conducted at the NuclearPhysics line at the Tandetrón installed in the CMAM, UAM. We are still working in preparing the papers connectedto the final results such as “Observation of α decay from a state in 10 B at 11.48 MeV”, PRC in acceptation process;“Improved limit on direct α decay of the Hoyle state”,PRL submitted and“Properties of 12 C resonances above thetriple-alpha threshold from studies in complete kinematics”, in preparation.The 3 He( 4 He,γ) 7 Be nuclear reaction plays an important role in determining both primordial 7 Li abundance and thehigh energy solar neutrino flux from the disintegration of 8 B coming from the 7 Be proton capture. Currently, thisreaction is one of the remaining major sources of uncertainty among the nuclear inputs required to calculate the highenergy solar neutrino flux. Experimental restrictions make impossible to measure the cross section of this reactionat the energy of interest (Gamow Peak 23 keV), thus, models use the extrapolation of the astrophysical factor(S 34 (E)) at zero energy determined at higher energies.In collaboration with University of York and The Weizmann Institute in Israel we have performed measurements atour beam line at the 5MV tandem accelerator CMAM (Univ. Autonoma de Madrid) in order to determine the crosssection of the 3 He+ 4 He 7 Be reaction as a function of energy. The technique used in the experiment is theactivation method which consists on the detection of the delayed 478 keV ray from the first excited state in 7 Li afterthe 7 Be electron capture decay. From the obtained cross section data we determine the astrophysical factor fordifferent center of mass energies. A paper is in preparation with the results obtained so far in this work. Thisexperiment is the thesis work of our JAEpredoc student M. Carmona.55