A nuclear track emulsion was exposed to a mixed beam of relativistic $^{12}$N, $^{10}$C, and $^7$Be nuclei having a momentum of 2 GeV/$c$ per nucleon. The beam was formed upon charge exchange processes involving $^{12}$C primary nuclei and their fragmentation. An analysis indicates that $^{10}$C nuclei are dominant in the beam and that $^{12}$N nuclei are present in it. The charge topology of relativistic fragments in the coherent dissociation of these nuclei is presented.
The dissociation features in nuclear track emulsion of $^9$Be, $^{9,10}$C, and $^{12}$N nuclei of 1.2 A GeV energy are presented. The data presented for the nucleus $^9$Be can be considered as evidence that there is a core in its structure in the form of 0$^+$ and 2$^+$ states of the $^8$Be nucleus having roughly equal weights. Events of coherent dissociation $^9$C$rightarrow 3^3$He associated with the rearrangement of the nucleons outside the $alpha$-clustering are identified. A pattern of the charge fragment topology in the dissociation of $^{10}$C and $^{12}$N nuclei is obtained for the first time. Contribution of the unbound nucleus decays to the cascade process $^{10}$C$rightarrow ^9$B$rightarrow ^8$Be is identified.
Production of ensembles of $alpha$-particle triples associated with the Hoyle state (the second excited state of the ${}^{12}$C nucleus) in peripheral dissociation of relativistic ${}^{12}$C nuclei is studied. Stacks of nuclear track emulsion pellicles exposed to ${}^{12}$C with an energy from hundreds MeV to a few GeV per nucleon serve as the material for studies. The Hoyle state decays are reconstructed via measurement of emission angles of $alpha$ particles with the precision sufficient for identification of the unstable ${}^{8}$Be nucleus. The estimate of the contribution of Hoyles state to the ${}^{12}$C $to$ 3$alpha$ dissociation is 10-15%.
Nuclear track emulsion is exposed to a beam of radioactive $^8$He nuclei with an energy of 60 MeV and enrichment of about 80% at the ACCULINNA separator. Measurements of 278 decays of the $^8$He nuclei stopped in the emulsion allow the potential of the $alpha$ spectrometry to be estimated and the thermal drift of $^8$He atoms in matter to be observed for the first time.
indent First results of the exposure of nuclear track emulsions in a secondary beam enriched by $^9$C nuclei at energy of 1.2 A GeV are described. The presented statistics corresponds to the most peripheral $^9$C interactions. For the first time a dissociation $^9$C $to3^3$He not accompanied by target fragments and mesons is identified.par
The technique of nuclear track emulsions is used to explore the fragmentation of light relativistic nuclei down to the most peripheral interactions - nuclear white stars. A complete pattern of therelativistic dissociation of a $^8$B nucleus with target fragment accompaniment is presented. Relativistic dissociation $^{9}$Be$to2alpha$ is explored using significant statistics and a relative contribution of $^{8}$Be decays from 0$^+$ and 2$^+$ states is established. Target fragment accompaniments are shown for relativistic fragmentation $^{14}$N$to$3He+H and $^{22}$Ne$to$5He. The leading role of the electromagnetic dissociation on heavy nuclei with respect to break-ups on target protons is demonstrated in all these cases. It is possible to conclude that the peripheral dissociation of relativistic nuclei in nuclear track emulsion is a unique tool to study many-body systems composed of lightest nuclei and nucleons in the energy scale relevant for nuclear astrophysics.
R. R. Kattabekov
,K. Z. Mamatkulov
,D. A. Artemenkov
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(2011)
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"Exposure of Nuclear Track Emulsion to a Mixed Beam of Relativistic $^{12}$N, $^{10}$C, and $^7$Be Nuclei"
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Krivenkov Dmitry
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