Fragmentation channels of relativistic 7^7Be nuclei in peripheral interactions

Nuclei of $^7$Li were accelerated at the JINR Nuclotron. After the charge-exchange reaction involving these nuclei at an external target a second $^7$Be beam of energy 1.23A GeV was formed. This beam was used to expose photo-emulsion chambers. The mean free path for inelastic $^7$Be interactions in emulsion $\lambda$=14.0$\pm$0.8 cm coincides within the errors with those for $^6$Li and $^7$Li nuclei. More than 10% of the $^7$Be events are associated with the peripheral interactions in which the total charge of the relativistic fragments is equal to the charge of the $^7$Be and in which charged mesons are not produced. An unusual ratio of the isotopes is revealed in the composition of the doubly charged $^7$Be fragments: the number of $^3$He fragments is twice as large as that of $^4$He fragments. In 50% of peripheral interactions, a $^7$Be nucleus decays to two doubly charged fragments. The present paper gives the channels of the $^7$Be fragmentation to charged fragments. In 50% of events, the $^7$Be fragmentation proceeds only to charged fragments involving no emission of neutrons. Of them, the $^3$He+$^4$He channel dominates, the $^4$He+d+p and $^6$Li+pchannels constitute 10% each. Two events involving no emission of neutrons are registered in the 3-body $^3$He+t+p and $^3$He+d+d channels. The mean free path for the coherent dissociation of relativistic $^7$Be nuclei to $^3$He+$^4$He is 7$\pm$1 m. The particular features of the relativistic $^7$Be fragmentation in such peripheral interactions are explained by the $^3$He+$^4$He 2-cluster structure of the $^7$Be nucleus.Comment: 10 pages, 3 figures, 3 tables, conference: Conference on Physics of Fundamental Interactions, Moscow, Russia, 5-9 Dec 200

Investigation of Light Nucleus Clustering in Relativistic Multifragmentation Processes

The use of emulsions for studying nuclear clustering in light nucleus fragmentation processes at energies higher than 1A GeV is discussed. New results on the topologies of relativistic Li-7 and B-10 nucleus fragmentation in peripheral interactions are given. A program of research of the cluster structure in stable and radioactive nuclei is suggested.Comment: 4 pages, 1 figure. Presented at Conference on Fundamental Interactions, 2-6 December 2002, ITEP, Moscow, Russia (misprints are removed

Topology of "white" stars in relativistic fragmentation of light nuclei

In the present paper, experimental observations of the multifragmentation processes of light relativistic nuclei carried out by means of emulsions are reviewed. Events of the type of "white" stars in which the dissociation of relativistic nuclei is not accompanied by the production of mesons and the target-nucleus fragments are considered. A distinctive feature of the charge topology in the dissociation of the Ne, Mg, Si, and S nuclei is an almost total suppression of the binary splitting of nuclei to fragments with charges higher than 2. The growth of the nuclear fragmentation degree is revealed in an increase in the multiplicity of singly and doubly charged fragments with decreasing charge of the non-excited part of the fragmenting nucleus. The processes of dissociation of stable Li, Be, B, C, N, and O isotopes to charged fragments were used to study special features of the formation of systems consisting of the lightest $\alpha$, d, and t nuclei. Clustering in form of the $^3$He nucleus can be detected in "white" stars via the dissociation of neutron-deficient Be, B, C, and N isotopes.Comment: 20 pages, 3 figures, 9 tables, conference: Conference on Physics of Fundamental Interactions, Moscow, Russia, 1-5 Mar 2004.(Author's translation

Special features of the 9^9Be→\to2He fragmentation in emulsion at an energy of 1.2~A~GeV

The results of investigations of the relativistic $^9$Be nucleus fragmentation in emulsion which entails the production of two He fragments of an energy of 1.2~A~GeV are presented. The results of the angular measurements of the $^9$Be$\to$2He events are analyzed. The $^9$Be$\to^8$Be+n fragmentation channel involving the $^8$Be decay from the ground (0$^+$) and the first excited (2$^+$) states to two $\alpha$ particles is observed to be predominant.Comment: 10 pages, 6 figures, conference: Conference on Physics of Fundamental Interactions, Moscow, Russia, 5-9 Dec 2005 (Author's translation

sup 1 sup 0 B nucleus fragment yields

Without any free parameters, yields of boron projectile fragments have been received from calculations of a model of the cold fragmentation proces

Experimental study of the fragmentation of relativistic nuclei

Section II. Experimental Investigations of Nuclear Reactions Mechanism

Experimental study of the fragmentation of relativistic nuclei

Section II. Experimental Investigations of Nuclear Reactions Mechanism