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G. I. Orlova

Publications and source records attributed to G. I. Orlova.

At least 19 recordsLinked to original sources
arXiv2011

Coherent Dissociation $^{16}$O~$\rightarrow$~4$α$ in Photoemulsion at an Incident Momentum of 4.5 GeV/$c$ per Nucleon

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.

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arXiv2011

Exposure of Nuclear Track Emulsion to a Mixed Beam of Relativistic $^{12}$N, $^{10}$C, and $^7$Be Nuclei

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.

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arXiv2011

Coherent Dissociation of Relativistic C-9 Nuclei

Results on the coherent dissociation of relativistic $^9$C nuclei in a nuclear track emulsion are described. These results include the charge topology and kinematical features of final states. Events of C-9 to 3He-3 coherent dissociation are identified.

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arXiv2010

Nuclear emulsion with molybdenum filling for observation of $ββ$ decay

The usage of nuclear emulsion with molybdenum filling for observation of $ββ$ decay are shown to be possible. Estimates for 1 kg of $^{100}$Mo with zero background give the sensitivity for the $0νββ$ decay of $^{100}$Mo at the level of $\sim 1.5\cdot 10^{24}$ y for 1 year of measurement.

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arXiv2009

Fragmentation of relativistic nuclei in peripheral interactions in nuclear track emulsion

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$\to2α$ 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.

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arXiv2009

Electromagnetic dissociation of relativistic $^8$B nuclei in nuclear track emulsion

Experimental data on fragmentation channels in peripheral interactions of $^8$B nuclei in nuclear track emulsions are presented. A detailed analysis made it possible to justify selections of events of the electromagnetic-dissociation process $^8$B $\to^7$Be + \emph{p} and to estimate its cross section. Events of $^{10}$C peripheral dissociation that were observed in the same exposure are described.

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arXiv2006

Peripheral fragmentation of relativistic $^{11}$B nuclei in photoemulsion

Experimental results on peripheral fragmentation of relativistic $^{11}$B nuclei are presented. In the experiment the emulsions exposured to $^{11}$B beam with momentum 2.75 A GeV/c at the JINR Nuclotron are used. The relative probability of various fragmentation channels for nucleus breakups (class A) and more violent peripheral interactions (class B) have been determined. For classes under investigations the sum of the fragment charges in narrow forward cone is equal to the projectile charge, but in the events of class A there are no secondary particles and in the events of class B there are. In both classes the main channels is $^{11}$B$\to$2He+X: 62% and 50%, corresponding. The main channel $^{11}$B$\to$2(Z$_{fr}$=2)+(Z$_{fr}$=1) was investigated in details. Momentum measurements of single-charged fragments have been done to determine number of p, d and t in the channel. This way it was found that the ratio N$_{p}$ : N$_{d}$ : N$_{t}$ is about 1:1:1 for $^{11}$B nuclei dissociation and about 15:5:1 for peripheral interactions of $^{11}$B nuclei.

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arXiv2006

Peripheral fragmentation of the $^8$B nuclei at an energy of 1.2A GeV in nuclear track emulsion

The results of investigations dealing with the charge topology of the fragments produced in peripheral dissociation of relativistic $^8$B nuclei in emulsion are presented. 55 events of peripheral dissociation of the $^8$B nucleus were selected from the events which do not involve the production of the target-nucleus fragments and mesons (`` white\rq\rq ~stars). A leading contribution of the $^8$B$\to^7$Be+p mode having the lowest energy threshold was revealed on the basis of those events. Information on the relative probability of dissociation modes with a larger multiplicity was obtained. The dissociation of a $^7$Be core in $^8$B indicates an analogy with that of the free $^7$Be nucleus.\par The transverse momentum distributions of the fragments from the $^8$B$\to^7$Be+p dissociation mode were obtained. Their small average value, $<$P$_t>$= 52 MeV/c, in the c.m.s. suggests a low binding energy of the external proton in the $^8$B nucleus. An indication for a strong azimuthal correlation of the $^7$Be and p fragments was got.

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arXiv2006

Peripheral interactions of relativistic $^{14}$N nuclei with emulsion nuclei

The results of investigations of the dissociation of a $^{14}$N nucleus of momentum 2.86~A~GeV/c in photo-emulsion are presented. The main characteristics of these reactions, that is the cross sections for various fragmentation channels, are given. The fragmentation was analyzed by means of an invariant approach. The momentum and correlation characteristics of $α$ particles for the $^{14}$N$\to3α$+X channel in the laboratory system and the rest systems of 3$α$ particles were considered. The results obtained for the $^{14}$N nucleus are compared with similar data for the $^{12}$C and $^{16}$O nuclei.

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arXiv2006

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 $α$, 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.

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arXiv2006

Special features of the $^9$Be$\to$2He 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 $α$ particles is observed to be predominant.

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arXiv2006

Dissociation of relativistic nuclei in peripheral interactions in nuclear track emulsion

Possibilities of the nuclear emulsion technique for the study of the systems of several relativistic fragments produced in the peripheral interactions of relativistic nuclei are discussed. The interactions of the $^{10}$B and $^{9}$Be nuclei in emulsion are taken as an example to show the manifestation of the cluster degrees of freedom in relativistic fragmentation. For the case of the relativistic $^{9}$Be nucleus dissociation it is shown that exact angular measurements play a crucial role in the restoration of the excitation spectrum of the alpha particle fragments. The energy calibration of the angular measurements by the $^{9}$Be nucleus enables one to conclude reliably about the features of internal velocity distributions in more complicated systems of relativistic $α$ particles.

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arXiv2006

Clustering in light nuclei in fragmentation above 1 A GeV

The relativistic invariant approach is applied to analyzing the 3.3 A GeV $^{22}$Ne fragmentation in a nuclear track emulsion. New results on few-body 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 few-body aspects of nuclear astrophysics.

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arXiv2006

Studies of light nicleus clustering in relativistic multifragmentation processes

We give an overview of results and prospects of nuclear clustering studies on the grounds of the observations of interactions of light stable and radioactive nuclei with an initial energy above 1 A GeV in nuclear emulsions. Thank to the best spatial resolution and the full solid angle acceptance provided by nuclear emulsions, such an approach allows one to obtain unique and evident observations reecting cluster-like features in light nuclear structures. New results on dissociation of $^7$Be in very peripheral interactions with emulsion nuclei are presented. The importance of this research for the physics of few body nuclear systems and the related problems of nucleosynthesis is noted. The paper is illustrated with characteristic images obtained by means of a microscope equipped with a CCD camera. The discussed explorations are provided with the beams of the Synchrophasotron and Nuclotron of JINR, Dubna. Future investigations are suggested to be carried out in relativistic beams of He, Be, B, C, and N isotopes.

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arXiv2005

Azimuthal Structures of Produced Particles in Heavy Ion Interactions

The angular substructures of particles produced in 208Pb at 158 A GeV/c and 197Au at 11.6 A GeV/c induced interactions with Ag(Br) nuclei in emulsion detector have been investigated. Nonstatistical ring-like substructures of produced particles in azimuthal plane of a collision have been found and their parameters have been determined.

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arXiv2004

Peculiarities in produced particles emission in 208Pb + Ag(Br) interactions at 158 A GeV/c

The angular structures of particles produced in 208Pb induced collisions with Ag(Br) nuclei in an emulsion detector at 158 A GeV/c have been investigated. Nonstatistical ring-like substructures in azimuthal plane of the collision have been found and their parameters have been determined. The indication on the formation of the ring-like substructures from two symmetrical emission cones - one in the forward and other in the backward direction in the center-of mass system have been obtained. The ring-like substructures parameters have been determined. The experimental results are in an agreement with I.M. Dremin idea, that mechanism of the ring-like substructures formation in nuclear collisions is similar to that of Cherenkov electromagnetic radiation.

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arXiv2003

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.

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