1 Study of 7 Be relativistic fragmentation in nuclear track emulsion Denis Artemenkov, VBLHE, JINR ( for the BECQUEREL collaboration )

1 Study of 7 Be relativistic fragmentation in nuclear track emulsion Denis Artemenkov, VBLHE, JINR ( for the BECQUEREL collaboration ) 2 BECQUEREL at the JINR Nuclotron is devoted systematic exploration of clustering features of light stable and radioactive nuclei. The fragmentation of a large variety of light nuclei was investigated using the emulsions exposed to few A GeV nuclear beams at JINR Nuclotron. A nuclear track emulsion is used to explore the fragmentation of the relativistic nuclei. 3 Study of relativistic 7 Be fragmentation in nuclear track emulsion in JINR 7 Li 7 Be (charge exchange, at 1.2 A GeV) 2004 Relativistic fragments Target fragments Event number 2Hen b =0 n b > He+2Hn b =0 n b > Hn b =0 n b > Li+Hn b =0 n b > Totaln b =0 n b > C 7 Be (in mixed beam of 12 N+ 10 C+ 7 Be at 1.2 A GeV) 2006 Table 1. Charge composition of the fragments in events with Q=4 4 55 Ion Physics Electromagnetic Dissociation Electromagnetic dissociation is liberation of nucleons or nuclear fragments as a result of electromagnetic field by exchange of virtual photons, rather than the strong nuclear force It is important for relativistic nuclear-nuclear interaction, especially where the proton number of the nucleus is large G4EMDissociation model and cross section are an implementation of the NUCFRG2 (NASA TP 3533) physics and treats this electromagnetic dissociation (ED). 6 G4EMDissociation G4EMDissociationCrossSection Started: 3000 of 7 Be nuclei at 1.2 A GeV Produced: 7 events of 7 Be 6 Be+n; Data modeling of 7 Be EM dissociation at 1.2 A GeV 6 Be Atomic Mass: amu Excess Mass: keV Binding Energy: keV Spin: 0+ Half life: 92 keV (5.0 fs) Mode of decay: 2 Proton to He-4 Decay energy: MeV 7 7 Be He H H 7 Be He+2H 7 Be 6 Be+n 4 He+2 1 H+n ? 7 Be 6 Be n 4 He p p n 8 6 5 Li 12 C 7 Be (in mixed beam of 12 N+ 10 C+ 7 Be at 1.2 A GeV), 2006 9 7 Be 2He 7 Li 7 Be (charge exchange, at 1.2 A GeV) Be He 10 12 C 7 Be (in mixed beam of 12 N+ 10 C+ 7 Be at 1.2 A GeV) Li 7 Be (charge exchange, at 1.2 A GeV) 2004 11 exp =14,2 0,2 cm (our experiment) Mean free path inel 12 Summary The possibilities of nuclear track emulsion for study of fragmentation of relativistic light nuclei is shown. The production of unstable 6 Be in electromagnetic interactions of 7 Be with emulsions nuclei is discussed. The most probable channels for 7 Be fragmentation are overviewed. Thank you for your attention! 13