Publications (77)96.06 Total impact
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ABSTRACT: First searches for the coherent dissociation of relativistic oxygen nuclei into four a particles are reported. It is shown that reactions of this type are characterized by a significantly lower decay temperature than the conventional multifragmentation of residual projectile nuclei. The momentum spectra and correlations of a panicles are not reproduced by the simple statistical model of direct fragmentation. The possibility that the oxygen nucleus undergoing fragmentation acquires a nonzero angular momentum in the collision process is discussed.  [Show abstract] [Hide abstract]
ABSTRACT: We report on recent results obtained by the EMUO1 collaboration from studies of 16O + emulsion, at 14.6, 60 and 200 A GeV, and 32S + emulsion and 32S + Au interactions at 200 A GeV. Showerparticle production in oxygeninduced interactions are studied over the energy range 2.1200 A GeV. Scaling and limiting fragmentation are observed. Multiplicity and angular distributions of low energy targetassociated particles are presented and compared with distributions obtained using the Ranft and the Fritiof simulation codes.  [Show abstract] [Hide abstract]
ABSTRACT: The full destruction (FD, that implies the disintegration into singly and doubly charged fragments only) characteristics are presented for some light nuclei ( 6 12 C, 8 16 O, 10 22 Ne, and 14 28 Si) with an energy of 3.7A GeV and heavy projectiles 79 197 Au (10.7A GeV) and 82 208 Pb (158A GeV) interacting with target nuclei in a photoemulsion. It is shown that (i) the average number of fragments, the realization of various fragmentation channels, and the degree of crushing for light projectiles substantially depend on the charge of a residual nucleus and on the mass of a target nucleus; (ii) the FD probability for residual nuclei with the same charge, as well as the multiplicity of fragments for the same impact parameter of heavy nuclei, are independent of the energy; and (iii) the integral distribution of transverse momenta of doubly charged fragments is described by two exponents (the logarithmic plot exhibits a break).  [Show abstract] [Hide abstract]
ABSTRACT: We analyse the multifractal structure of moments Gq in terms of a new variable X on data of 197Au, 32S and 16O induced interactions with emulsion nuclei and Monte Carlo generated samples. The dynamical properties of the produced particles are mapped onto multifractal spectra. We compare ln G in experimental data of 197Au, 32S and 16O with pure statistical fluctuations. It is shown that the stochasticity plays an important role for the Gmoments.  [Show abstract] [Hide abstract]
ABSTRACT: The relativistic invariant approach is applied to analyzing the 3.3 A GeV $^{22}$Ne fragmentation in a nuclear track emulsion. New results on fewbody dissociations have been obtained from the emulsion exposures to 2.1 A GeV $^{14}$N and 1.2 A GeV $^{9}$Be nuclei. It can be asserted that the use of the invariant approach is an effective means of obtaining conclusions about the behavior of systems involving a few He nuclei at a relative energy close to 1 MeV per nucleon. The first observations of fragmentation of 1.2 A GeV $^{8}$B and $^{9}$C nuclei in emulsion are described. The presented results allow one to justify the development of fewbody aspects of nuclear astrophysics.  [Show abstract] [Hide abstract]
ABSTRACT: The radioecological situation in the EastKazakhstan region was studied by electron paramagnetic resonance (EPR), radiography and nuclear spectroscopy methods. The eastern part of this region borders the Semipalatinsk nuclear test site. Radiation doses for 33 residents of this region were measured by EPR dosimetry in tooth enamel. It was found that for 25% of the residents the measured radiation doses do not exceed the background level. The rest of the doses exceed the background level by a factor of 2–4 on the average. A new method of nuclear explosion dating was developed on the basis of the EPR measurements of the free radical concentration in annual tree rings. Their maximal concentration corresponds to the years when nuclear explosions were executed. The obtained results correlate well with the commonly accepted radiography method. Both methods show a maximum of radionuclide levels in the years of nuclear testing. The plutonium239 content in residents hair samples was found to be equal to (0.8±0.2)·10−9 g/kg and with activity of 1.9±0.4 Bq/kg. This is by a factor of 20 higher than the permitted content for the population. 
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ABSTRACT: Experimental observations of the multifragmentation of relativistic light nuclei by means of emulsions are surveyed. Events that belong to the type of “white stars” and in which the dissociation of relativistic nuclei is not accompanied by the production of mesons and targetnucleus fragments are considered. An almost complete suppression of the binary splitting of nuclei to fragments of charge in excess of two, Z > 2, is a feature peculiar to charge topology in the dissociation of Ne, Mg, Si, and S nuclei. An increase in the degree of nuclear fragmentation manifests itself in the growth of the multiplicity of singly and doubly charged fragments (Z = 1, 2) as the charge of the unexcited fragmentingnucleus part (which is the main part) decreases. Features of the production of systems formed by extremely light nuclei α, d, and t are studied in the dissociation of the stable isotopes of Li, Be, B, C, N, and O to charged fragments. Manifestations of 3He clustering can be observed in “white stars” in the dissociation of neutrondeficient isotopes of Be, B, C, and N.  [Show abstract] [Hide abstract]
ABSTRACT: Various flow phenomena observed by a unique emulsion method are reviewed. The experimental data of the emission of projectile and target fragments and relativistic particles in collisions of 1–160 A GeV/c 16O, 22Ne, 28Si, 32S, 84Kr, 197Au, and 208Pb nuclei with 108Ag (80Br) targets are investigated. The transversemomentum approach, the flowangle analysis using principal vectors, the azimuthal correlation functions, the method of azimuthal correlations between charged secondaries, and the method of Fourier expansion of the azimuthal angle distributions are applied. Evidence of the directed flow of spectators has been obtained in the mediumimpact nuclear interactions. In azimuthal distributions, with respect to the reaction plane, the signal of the elliptic flow of participants has been observed.  [Show abstract] [Hide abstract]
ABSTRACT: The experimental data on the interactions of 10.6A GeV gold nuclei in nuclear emulsions are analyzed with particular emphasis of target separation interactions and study of critical exponents. Charged fragment moments, conditional moments as well as two and three – body asymmetries of the fast moving projectile particles are determined in terms of the total charge remaining bound in the multiply charged projectile fragments. Some differences in the average yields of helium nuclei and heavier fragments are observed, which may be attributed to a target effect. However, two and threebody asymmetries and conditional moments indicate that the breakup mechanism of the projectile seems to be independent of target mass. We looked for evidence of critical point observable in finite nuclei by study the resulting charged fragments distributions. We have obtained the values for the critical exponents γ, β and τ and compare our results with those at lower energy experiment (1.0A GeV data). The values suggest that a phase transition like behavior, is observed.  [Show abstract] [Hide abstract]
ABSTRACT: Angular distributions of charged particles produced in 16O and 32S collisions with nuclear track emulsion were studied at momenta 4.5 and 200 A GeV/c. Comparison with the angular distributions of charged particles produced in protonnucleus collisions at the same momentum allows to draw the conclusion, that the angular distributions in nucleusnucleus collisions can be seen as superposition of the angular distributions in nucleonnucleus collisions taken at the same impact parameter bNA, that is mean impact parameter between the participating projectile nucleons and the center of the target nucleus.  [Show abstract] [Hide abstract]
ABSTRACT: The nuclear emulsion was exposed at CERN by the lead projectile at 160 A GeV. The angles between any pair of fragments with Z= 2–4 have been measured in the emulsion plane for the events which did not contain heavy fragments. The constant characterizing the normal angle (φ) distribution of the fragment momentum projection onto the emulsion plane with respect to initial projectile momentum p 0 is found to be σφ= (0.37 ± 0.02) mrad. Corresponding value σ0= (121 ± 6) MeV/c of nucleon momentum distribution in the lead nucleus coincides with that expected from Fermi momentum distribution for this nucleus. The peak in the pairangle distribution of doublecharged fragments, 8Be → 2α, is presented for the region of small angles (<0.1 mrad). The fraction of αparticles coming from the decay of the ground state 8Be is found to be (13 ± 2)% of their whole number.  [Show abstract] [Hide abstract]
ABSTRACT: Charge distributions of projectile fragments produced in the interactions of 22Ne beams with emulsion at 4.1A GeV/c have been studied. Correlations between projectile and target fragments and among projectile fragments are presented. The change of charge yield distribution with the violence of the collision has been shown. The present analysis contradicts theoretical calculations describing the inclusive charge yield distribution of fragments by a single process.  [Show abstract] [Hide abstract]
ABSTRACT: Analysis of emission of projectile and target fragments in 22Ne+Ag(Br) collisions at 4.1A GeV/c is carried out to study peculiarities of particle 'sideward flow'. The possibility of determining the reaction plane is considered. 'Bounceoff' of 22Ne projectile fragments is observed by investigating their projections onto the reaction plane. The angular distribution of slow fragments has a maximum which is due to 'side splash'. By studying projections onto the azimuthal plane, data on 'sideward flow' are obtained. An increase of ranges is observed for slow fragments emitted in the direction of the 'side splash'.  [Show abstract] [Hide abstract]
ABSTRACT: An equation is presented, which allows us to calculate the dependence of the multiplicity of the particles produced in nucleus  nucleus collisions, , on an experimentally measured value , which is strongly correlated to the impact parameter b. The equation combines data from a wide range of projectile masses (  197) over a large momentum region . The possible meaning of the parameters is discussed in the context of a simple geometrical model.  [Show abstract] [Hide abstract]
ABSTRACT: We analyse the multifractal structure of moments G(q) in terms of a new variable X on data of (197)AU, S32, and O16 induced interactions with emulsion nuclei and Monte Carlo generated samples. The dynamical properties of the produced particles are mapped onto multifractal spectra. We compare In(G) in experimental data of Au197, S32, and O16 with pure statistical fluctuations. It is shown that the stochasticity plays an important role for the Gmoments.  [Show abstract] [Hide abstract]
ABSTRACT: Using emulsion detectors a transversemomentum analysis of projectile fragments has been performed in Au induced nuclear interactions at 11.6 A GeV/c. Evidence for collective flow of the projectile fragments has been obtained. Angular distributions of the principal vectors of projectile and target fragments have shown strong azimuthal correlation.  [Show abstract] [Hide abstract]
ABSTRACT: Using emulsion detectors a transversemomentum analysis of projectile fragments has been performed in Au induced nuclear interactions at 11.6 A GeV/c. Evidence for collective flow of the projectile fragments has been obtained. Angular distributions of the principal vectors of projectile and target fragments have shown strong azimuthal correlation.  [Show abstract] [Hide abstract]
ABSTRACT: Using emulsion detectors a transversemomentum analysis of projectile fragments has been performed in Au induced nuclear interactions at 11.6 A GeV/c. Evidence for collective flow of the projectile fragments has been obtained. Angular distributions of the principal vectors of projectile and target fragments have shown strong azimuthal correlation.  [Show abstract] [Hide abstract]
ABSTRACT: The complete charge distribution of products from Au nuclei fragmenting in nuclear emulsion at 10.7A GeV has been measured. Multiplicities of produced particles and particles associated with the target source are used to select peripheral and central events. A statistical analysis, based on eventbyevent charge distributions, show that a population of subcritical, critical and supercritical events, i.e. a phase transition like behaviour, is observed among peripheral collisions.
Publication Stats
628  Citations  
96.06  Total Impact Points  
Top Journals
Institutions

2011

National Academy of Sciences of the Republic of Kazakhstan
Almaty, Almaty Qalasy, Kazakhstan


2007

Yerevan Physics Institute
Ayrivan, Yerevan, Armenia


20062007

Ministry of Education and Science of the Republic of Kazakhstan
Astana, Astana Qalasy, Kazakhstan


19912007

Институт физики высоких энергий
Protvino, Moskovskaya, Russia


19952006

Almaty Institute of Physics and Technology
Almaty, Almaty Qalasy, Kazakhstan 
Slovak Academy of Sciences
 Institute of Experimental Physics
Bratislava, Bratislavsky Kraj, Slovakia


1994

IFAE Institute for High Energy Physics
Barcino, Catalonia, Spain


19921993

University of Washington Seattle
 Department of Physics
Seattle, Washington, United States
