W. Bradfield-Smith

Louvain-Edinburgh Detector Array (LEDA): a silicon detector array for use with radioactive nuclear beams

We discuss the design and implementation of the Louvain-Edinburgh Detector Array: a charged particle detector array composed of silicon-strip detectors which is used for the study of nuclear astrophysics and nuclear physics using radioactive nuclear beams at the Louvain-1a-Neuve radioactive nuclear beam facility

Elastic 2n-transfer in the 4He(6He,6He)4He scattering

The elastic scattering He-4(He-6,He-6)He-4 has been investigated at center-of-mass energies of 11.6 and 15.9 MeV. Differential cross sections are determined using a post-accelerated He-6 (T-1/2 = 0.807 s) beam in the center-of-mass angular range between 50 and 140 degrees. The comparison of the measured data with calculations using a double folding potential shows evidence for the 2n-transfer process in the He-4(He-6,He-6)He-4 elastic scattering

The 18F(p,α) reaction and its astrophysical implications

F-18 radioactive beams were used to measure the F-18(p,alpha) reaction in the c.m. energy ranges of 265-535 keV and 550-740 keV. In each case, a resonant level was clearly detected, of which the resonant strength and some other properties were deduced. The astrophysical reaction rate was calculated down to the novae peak temperature. Consequences for the hot CNO cycles were drawn

Different aspects of nuclear structure and reaction mechanisms in the collision 13N+11B

The reaction N-13 + B-11 has been investigated at two 13N beam energies: 29.5 and 45 MeV, Charged particles and gamma rays emitted in the reactions have been detected using a large array of silicon strip detectors and BaF2 scintillators, respectively. Several reaction channels have been analysed with different aims. The proton transfer reaction B-11(N-13, C-12)C-12 to various excited states of C-12 has been studied to obtain information on the N-13(g.s.) structure. The excitation energy of the Mg-24 compound nucleus was in the region where several resonances occur in the C-12 + C-12 system. The six-alpha decay of the Mg-24 intermediate system has been studied. Some of these events have been identified as coming from the break-up of two C-12* in the 3(1)(-)-3(1)(-) and 3(1)(-)-0(2)(+) states. The total fusion cross section has also been extracted from the data. In order to extract information on the isospin purity/mixing in Mg-24 at high excitation energy (E-x similar to 47 MeV), the GDR gamma emission from this self-conjugate nucleus has been studied. A comparison of gamma spectra has been undertaken for the reactions N-13 + B-11 and N-14 + B-10

Measurement of the 4He(6He, 6He)4He cross section with a 4He-implanted Al target

In order to obtain information on a possible two-neutron component in the 6He wavefunction, we investigated the 4He( 6He, 6He) 4He elastic scattering at beam energies of 29.1, 29.6 and 40 MeV and at center-of-mass angles between 20 and 163 degrees. The experiments were performed at the ARENAS Radioactive Ion Beam Facility in Louvain-La-Neuve. We used a 4He-implanted aluminium foil as a target. A 4He thickness of about 2-3 * 10 17 particlescm 2 was obtained implanting 4He nuclei at energies between 20 and 80 keV in 0.7- mu m-thick foils. Data collected in a larger angular range than previous measurements give additional evidence for the 2n-transfer process to take place in the 4He( 6He, 6He) 4He scattering. Our results demonstrate the possibility of using a 4He-implanted target in experiments with low-intensity beams, like radioactive beams, where deterioration of the target is irrelevant.

The transfer reaction11B(13N,12C)12C

SummaryThe transfer reaction11B(13N,12C)12C* has been investigated at the two laboratory energiesElab =45 MeV andElab =29.5 MeV. Particle-γ and particleparticle coincidences have been measured. The coincidence between a heavy ion and the 15.1 MeV γ-ray emitted from12C* shows transition to the12Cgs +12C*15.1 and12C*4.44 +12C*15.1 exit channels. These indicate the mixed ground-state structure of13N. DWBA calculations have also been performed. Analysis of particle-particle coincidence data revealed the presence of transfer channels also to unbound states of12C such as12Cgs +12C* (E* >7.64 MeV) and12C*4.44 +12C* (E* >7.64 MeV). The angular distributions have been extracted for these two channels. Six-alpha-particle events have also been analyzed. Some of these events have been identified as coming from11B(13N,12C*)12C* reaction. An enhancement in the six-α cross-section is observed at an excitation energy for the compound nucleus24Mg close to the 46 MeV resonances observed in12C +12C inelastic scattering. These six-alphas events are generated mostly from the break-up of12C(3-1) +12C(3-1) and therefore seems not to be associated with the six-alphas chain state.

Elastic 2n-transfer in the 4He(6He, 6He)4He scattering

The elastic scattering 4He(6He, 6He)4He has been investigated at center-of-mass energies of 11.6 and 15.9 MeV. Differential cross sections are determined using a post-accelerated 6He (T1/2=0.807 s) beam in the center-of-mass angular range between 50 and 140 degrees. The comparison of the measured data with calculations using a double folding potential shows evidence for the 2n-transfer process in the 4He(6He, 6He)4He elastic scattering.

Elastic transfer in 4He(6He,6He)4He

We have investigated the reaction {sup 4}He({sup 6}He,{sup 6}He){sup 4}He at c.m. energies of 11.6 and 15.9 MeV and determined the differential elastic cross section in the angular range between 50 and 145 degree. The comparison of the measured data with DWBA calculations using a double folding potential for the {sup 6}He-{sup 4}He scattering shows evidence for the elastic transfer of a di-neutron cluster between the two {sup 4}He cores.We have investigated the reaction 4He(6He,6He)4He at c.m. energies of 11.6 and 15.9 MeV and determined the differential elastic cross section in the angular range between 50 and 145 degree. The comparison of the measured data with DWBA calculations using a double folding potential for the 6He-4He scattering shows evidence for the elastic transfer of a di-neutron cluster between the two 4He cores.

Formation and decay of 24Mg in the 13N+11B collision

Different aspects of the formation and decay of 24 Mg in the collision 13 N+ 11 B have been studied using a large solid angle and highly segmented Silicon strip detector. Results concerning the fusion cross section, the 6 α decay of 24 Mg and the GDR gamma ray emission are discussed.

Different aspects of 24Mg formation and decay using a radioactive 13N beam

Different aspects of the formation and decay of 24Mg in the collision 13N+11B have been studied using a large solid angle and highly segmented Silicon strip detector. Results concerning the fusion cross section, the 6 α decay of 24Mg and the GDR gamma ray emission are discussed.