P. I. Zarubin

Toward an Automated Analysis of Slow Ions in Nuclear Track Emulsion

Application of the nuclear track emulsion technique (NTE) in radioactivity and nuclear fission studies is discussed. It is suggested to use a HSP-1000 automated microscope for searching for a collinear cluster tri-partition of heavy nuclei implanted in NTE. Calibrations of -particles and ion ranges in a novel NTE are carried out. Surface exposures of NTE samples to a 252 Cf source started. Planar events containing fragments and long-range -particles as well as fragment triples only are studied. NTE samples are calibrated by ions Kr and Xe of energy of 1.2 and 3 A MeV. c 2015 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the National Research Nuclear University MEPhI (Moscow Engineering Physics Institute).

Unstable nuclei in dissociation of light stable and radioactive nuclei in nuclear track emulsion

A role of the unstable nuclei 6Be, 8Be and 9B in the dissociation of relativistic nuclei 7,9Be, 10B and 10,11C is under study on the basis of nuclear track emulsion exposed to secondary beams of the JINR Nuclotron. Contribution of the configuration 6Be + n to the 7Be nucleus structure is 8 ± 1% which is near the value for the configuration 6Li + p. Distributions over the opening angle of α-particle pairs indicate to a simultaneous presence of virtual 8Beg.s. and 8Be2+ states in the ground states of the 9Be and 10C nuclei. The core 9B is manifested in the 10C nucleus with a probability of 30 ± 4%. Selection of the 10C “white” stars accompanied by 8Beg.s. (9B) leads to appearance in the excitation energy distribution of 2α2p “quartets” of the distinct peak with a maximum at 4.1 ± 0.3 MeV. 8Beg.s. decays are presented in 24 ± 7% of 2He + 2H events of the 11C coherent dissociation and 27 ± 11% of the 3He ones. The channel 9B + H amounts 14 ± 3%. The 8Bg.s. nucleus is manifested in the coherent dissociation 10B → 2He + H with a probability of 25 ± 5% including 13 ± 3% of 9B decays. A probability ratio of the mirror channels 9B + n and 9Be + p is estimated to be 10 ± 1.

Dissociation of relativistic 10 B nuclei in nuclear track emulsion

Dissociation of 1.2 A GeV 10 C nuclei in nuclear track emulsionis is studied. It is shown that most precise angular measurements provided by this technique play a crucial role in the restoration of the excitation spectrum of the 2α + 2p system. Strong contribution of the cascade process 10 C → 9 B → 8 Be identified.

8Be and 9B nuclei in dissociation of relativistic 10B and 11C nuclei

Progress in the study of nuclear clustering in the relativistic 10B and 11C nuclei dissociation in nuclear track emulsion is presented. The contribution of the unbound 8Be and 9B nuclei to their structure is determined on the basis of measurements of the emission angles of relativistic He and H fragments.

Study of nuclear multifragmentation induced by ultrarelativistic μ-mesons in nuclear track emulsion

Exposures of test samples of nuclear track emulsion were analyzed. The formation of high-multiplicity nuclear stars was observed upon irradiating nuclear track emulsions with ultrarelativistic muons. Kinematical features studied in this exposure of nuclear track emulsions for events of the muon-induced splitting of carbon nuclei to three α-particles are indicative of the nuclear-diffraction interaction mechanism.

Unstable nuclei in coherent dissociation of relativistic nuclei 7,9Be, 10B and 10,11C

Contribution of the unstable nuclei 7Be, 8Be and ®B into coherent dissociation events (white stars) of relativistic nuclei 7,9Be, 10B and 10,11C is under study on the basis of a nuclear track emulsion exposed to beams of the JINR Nuclotron. Distributions over the opening angle of α-pairs indicate to a simultaneous presence of virtual 8Beg.s. and 8Be2+ states in the ground states of the 9Be and 10C nuclei. The core 9B is manifested in the 10C nucleus with a probability of (30 ± 4)%, Selection of the 10C white stars accompanied by 8Beg.s. (9B) leads to the appearance in the excitation energy distribution of 2α2p quartets of the distinct peak with a maximum at 4.1 ± 0.3 MeV. 8Beg.s. decays are presented in 21% 2He + 2H and 19% in the 3He of the all 11C white stars. 9Bg.s. decays are identified in white stars 11C → 2He + 2H constituting 14% of the 11C white stars. The 9B nucleus. is manifested in the white stars 10B → 2He + 2H with a probability of (9 ± 1)%. For the 10B case yield of 8Beg.s. nuclei with the respect to 9B is about a factor of 3 higher than 9B.

Computer analysis of nuclear track emulsion exposed to thermal neutrons and Cf source

Application of the nuclear track emulsion technique (NTE) in radioactivity and nuclear fission studies is discussed. It is suggested to use a HSP-1000 automated microscope for searching for a collinear cluster tri-partition of heavy nuclei implanted in NTE. Calibrations of α-particles and ion ranges in a novel NTE are carried out. Surface exposures of NTE samples to a Cf-252 source started. Planar events containing fragments and long-range α-particles as well as fragment triples only are studied. Splittings induced by thermal neutrons are studied in boron-enriched emulsion. Use of the image recognition program ImageJ for obtaining characteristics of individual events and for events from the large scan area is presented.