Opažanje α-raspada 10B i 12B u 9Be +7Li reakcijama

The 10B and 12B excitation energy spectra have been obtained from the inclusive and coincident measurements of the 9Be +7Li reactions at Ebeam=52 MeV. Contributions of the 10B states below 10 MeV and of the 12B states below 16 MeV excitation have been resolved. 10B states at 4.77 and 6.56 MeV as well as groups of states around 5.1 and 6 MeV decaying into α +6Li, and of the state at 7.0 MeV decaying into α +6Li∗ have been found. These measurements give the first evidence for α +8Li decay of the 12B states. In our data, there is no evidence for the α +8Li∗ (0.98 MeV) and α +8Li∗ (2.26 MeV) decays of 12B. The influence of α-decaying 12B states on the cross section of the astrophysically important 8Li(α,n)11B reaction is discussed.Odredili smo uzbudne energijske spektre 10B i 12B uključivim i sudesnim mjerenjima reakcije 9Be+7Li na Esnop=52 MeV. Razdvojili smo doprinose stanja 10B ispod 10 MeV i stanja 12B ispod 16 MeV. Našli smo raspade stanja 10B na 4.77 i 6.56 MeV i grupa stanja oko 5.1 i oko 6 MeV u α +6Li, i stanja na 7.0 MeV u α +6Li∗ . Ovo su prva mjerenja u kojima se nalazi α +8Li raspad viših stanja 12B. Naši podaci ne ukazuju prisutnost α +8Li∗ (0.98 MeV) i α +8Li∗ (2.26 MeV) raspada 12B. Raspravljamo utjecaj stanja 12B koja podliježu α-raspadu na udarne presjeke astrofizički važne reakcije 8Li(α,n)11B

Opažanje α-raspada 10B i 12B u 9Be +7Li reakcijama

The 10B and 12B excitation energy spectra have been obtained from the inclusive and coincident measurements of the 9Be +7Li reactions at Ebeam=52 MeV. Contributions of the 10B states below 10 MeV and of the 12B states below 16 MeV excitation have been resolved. 10B states at 4.77 and 6.56 MeV as well as groups of states around 5.1 and 6 MeV decaying into α +6Li, and of the state at 7.0 MeV decaying into α +6Li∗ have been found. These measurements give the first evidence for α +8Li decay of the 12B states. In our data, there is no evidence for the α +8Li∗ (0.98 MeV) and α +8Li∗ (2.26 MeV) decays of 12B. The influence of α-decaying 12B states on the cross section of the astrophysically important 8Li(α,n)11B reaction is discussed.Odredili smo uzbudne energijske spektre 10B i 12B uključivim i sudesnim mjerenjima reakcije 9Be+7Li na Esnop=52 MeV. Razdvojili smo doprinose stanja 10B ispod 10 MeV i stanja 12B ispod 16 MeV. Našli smo raspade stanja 10B na 4.77 i 6.56 MeV i grupa stanja oko 5.1 i oko 6 MeV u α +6Li, i stanja na 7.0 MeV u α +6Li∗ . Ovo su prva mjerenja u kojima se nalazi α +8Li raspad viših stanja 12B. Naši podaci ne ukazuju prisutnost α +8Li∗ (0.98 MeV) i α +8Li∗ (2.26 MeV) raspada 12B. Raspravljamo utjecaj stanja 12B koja podliježu α-raspadu na udarne presjeke astrofizički važne reakcije 8Li(α,n)11B

Reakcija 11B(p,αα) 4He u uvjetima kolinearnosti

The 11B(p,αα) 4He reaction was measured at eight incident proton energies, from 2 to 5.5 MeV, for the collinearity configurations (an α-particle at rest in the c.m. system). The results are compared with predictions of the Sch¨afer model. Involvement of the 12C states with excitation energy between 17.8 and 21 MeV is discussed.Mjerena je reakcija 11B(p,αα) 4He za osam upadnih energija protona, od 2 do 5.5 MeV, u uvjetima kolinearnosti (jedna α-čestica miruje u sustavu centra masa). Rezultati su uspoređeni s predviđanjima Schaferovog modela. Diskutirana je uloga stanja jezgre 12C s energijama pobuđenja između 17.8 i 21 MeV

Reakcija 11B(p,αα) 4He u uvjetima kolinearnosti

The 11B(p,αα) 4He reaction was measured at eight incident proton energies, from 2 to 5.5 MeV, for the collinearity configurations (an α-particle at rest in the c.m. system). The results are compared with predictions of the Sch¨afer model. Involvement of the 12C states with excitation energy between 17.8 and 21 MeV is discussed.Mjerena je reakcija 11B(p,αα) 4He za osam upadnih energija protona, od 2 do 5.5 MeV, u uvjetima kolinearnosti (jedna α-čestica miruje u sustavu centra masa). Rezultati su uspoređeni s predviđanjima Schaferovog modela. Diskutirana je uloga stanja jezgre 12C s energijama pobuđenja između 17.8 i 21 MeV

Reaction studies with low-energy weakly-bound beams at INFN-LNS

The reaction dynamics of collisions involving halo or weakly bound nuclei, at energies around the Coulomb barrier, can be strongly affected by the structure of such nuclei. Very strong entrance channel effects have been observed on various reaction pocess such as, elastic scattering, fusion and direct reactions when comparing collision induced by the 6He and 11Be halo nuclei with the ones induced by their cores 4He and 10Be. Collisions induced by the stable weakly bound nuclei 6Li, 7Li show also some peculiarities in comparison to the ones induced by well bound nuclei; coupling with the break-up channel is in fact very important in reproducing low energy data. In this contribution an overview of our present understanding of the discussed topic will be given along with the discussion of some new preliminary results

Comparison of the effects of couplings to breakup channels in reactions induced by 6Li and 6He on the same 64Zn target

The experimental elastic scattering angular distributions for the weakly bound nuclei 6,7Li and for the halo nucleus 6He on the same 64Zn target at several energies around the Coulomb barrier were measured at the Laboratori Nazionali del Sud (LNS, Italy) and at the Cyclotron Research Center, Louvain La Neuve (Belgium), respectively. The measured elastic scattering angular distributions of these three systems at the same center of mass energy have been compared. The experimental data of the 6,7Li+ 64Zn systems have been analyzed within the CDCC method, while the 6He+64Zn data have been compared with both both CDCC and CRC calculations

Experimental investigation of exotic clustering in 13B and 14C using the resonance scattering method

In order to investigate the existence of molecular and/or exotic cluster configurations in Boron and Carbon n-rich isotopes we undertook two experiments: the first experimental study of exotic 9Li+α cluster states in 13B using the resonance scattering method at TRIUMF (Canada), and, with the same technique, the measurement of 10Be+α scattering at LNS in Catania, where a 10Be radioactive beam was produced for the first time. In order to measure the excitation function in a wide energy range, the beams were stopped in a Helium-flooded chamber. In the case of 13B, the elastic excitation function shows the presence of various peaks in an excitation energy region never explored before. In the case of 14C, our exclusive measurement of elastic scattering data with a high intensity beam, sheds some light on the contradictory previously published results [1, 2]

10Be i molekulska stanja

The 10Be excitation energy spectra have been obtained from the inclusive and coincident measurements of the reactions: 7Li +7Li at E0 = 8 and 30 MeV and 9Be +7Li at E0 = 52 MeV. Contributions of the 10Be states below 12 MeV in excitation have been observed. Decays of the states at 9.6, 10.2 and 11.8 into a +6He and, for the first time, into a +6He* have been found. The results are discussed in addition to the other experimental data and recent theoretical predictions. Proposals for future measurements to search for exotic structures in carbon nuclei are also made.Proučavamo ekscitacijske energijske spektre 10Be iz inkluzivnih i koincidentnih mjerenja reakcija 7Li +7Li na E0 = 8 i 30 MeV, te 9Be +7Li na E0 = 52 MeV. Opaženi su doprinosi stanja 10Be u energiji uzbude do 12 MeV. Nađeni su raspadi stanja na 9.6, 10.2 i 11.8 MeV na α +6He te, po prvi put, na α +6He∗. Ovi se rezultati razmatraju zajedno s ostalim eksperimentalnim podacima i novijim teorijskim predviđanjima. Predlažu se buduća mjerenja u kojima bi se tražila stanja lakih jezgara egzotične građe

10Be i molekulska stanja

The 10Be excitation energy spectra have been obtained from the inclusive and coincident measurements of the reactions: 7Li +7Li at E0 = 8 and 30 MeV and 9Be +7Li at E0 = 52 MeV. Contributions of the 10Be states below 12 MeV in excitation have been observed. Decays of the states at 9.6, 10.2 and 11.8 into a +6He and, for the first time, into a +6He* have been found. The results are discussed in addition to the other experimental data and recent theoretical predictions. Proposals for future measurements to search for exotic structures in carbon nuclei are also made.Proučavamo ekscitacijske energijske spektre 10Be iz inkluzivnih i koincidentnih mjerenja reakcija 7Li +7Li na E0 = 8 i 30 MeV, te 9Be +7Li na E0 = 52 MeV. Opaženi su doprinosi stanja 10Be u energiji uzbude do 12 MeV. Nađeni su raspadi stanja na 9.6, 10.2 i 11.8 MeV na α +6He te, po prvi put, na α +6He∗. Ovi se rezultati razmatraju zajedno s ostalim eksperimentalnim podacima i novijim teorijskim predviđanjima. Predlažu se buduća mjerenja u kojima bi se tražila stanja lakih jezgara egzotične građe