Emulsion Track Detector Research Articles

Studies of angular distribution of the grey particles in 16O-emulsion collision at 3.7A GeV

By means of [Formula: see text] emulsion track detectors, we report the characteristics of the experimental angular distributions of the fast target protons (grey particles) emitted in interactions of [Formula: see text]O with emulsion nuclei at 3.7A[Formula: see text]GeV. Grey tracks in nuclear emulsion corresponding protons with kinetic energy in the ranges [Formula: see text][Formula: see text]MeV. The angular distributions are compared with those resulting from interactions of other projectiles ([Formula: see text]C, [Formula: see text]Ne and [Formula: see text]Si) at nearly the same incident energy. These angular distributions are studied at different target sizes ([Formula: see text]-values) and at various projectile spectator charges ([Formula: see text]-values) in the framework of the modified Maxwell– Boltzmann statistical model. The nuclear limiting fragmentation hypothesis is shown to be fulfilled for these target protons angular distributions which are found to be independent of the target size and centrality of collisions. Also, the size of the projectile is found to be ineffective at Dubna energies. The angular distributions of all groups of events possess peaks positioned at [Formula: see text]. The calculated statistical moments of the distributions along with skewness and kurtosis are investigated in addition to the forward-backward asymmetry ratio [Formula: see text] for the different groups of events.

Multiplicity characteristics of the produced shower particles in backward direction-target and projectile dependence

In the present paper a detailed investigation of the multiplicity distribution of the produced shower particles in the backward hemisphere ( $$\theta _{\mathrm {Lab}} \ge 90^{\circ }$$ ) in nuclear emulsion track detector has been carried out. The present study involves interactions of $$^{\mathrm {16}}\hbox {O}$$ and $$^{\mathrm {32}}\hbox {S}$$ projectiles with CNO, AgBr and composite emulsion target at 4.5 AGeV/c. We have compared our results with the results obtained from the analysis of modified Fritiof model. Present study reveals that the production of single shower particle is the most dominant production mode of shower particles in the backward direction. This probability increases with the increase of target mass. The percentage of events having backward shower particles remains almost independent of the projectile beam. But it increases with the increase of target size. Average multiplicity of the shower particles in the backward direction reflects a weaker dependence on the mass number of the projectile beam. Multiplicity distribution of backward shower particles for both experimental and modified Fritiof model can be described by an expression $$\mathrm {P}_{\mathrm {N}} = {\mathrm {P}_{\mathrm {s}}\mathrm {N}_{\mathrm {B}}}^{-{\uplambda }_{\mathrm {B}}}$$ . The fitting parameter $${\uplambda }_{\mathrm {B}}$$ decreases as the target size increases. The decay constant has lower value for the heavier projectile. Higher order multiplicity moments and scaled variance of multiplicity distribution for the backward shower particles showed strong target dependence. Multiplicity distributions of the backward shower particles violate KNO scaling law. Modified Fritiof model failed to reproduce the various features of the multiplicity distribution.

Backward shower particle production in high energy nucleus–nucleus collisions — an outlook to centrality dependence

A detailed study on the centrality dependence of the different aspects multiplicity distribution of the shower particles produced in the backward direction ([Formula: see text] in nuclear emulsion track detector has been carried out for [Formula: see text]Ne-emulsion interactions at 4.1 AGeV/c. Depending on the values of the total charges or sum of the charges of noninteracting projectile fragments, event samples were classified into four centrality classes. From the analysis presented in this paper, qualitative information about the assembly of shower particles in the backward direction has been extracted.

Centrality dependence of pseudo-rapidity distribution in nucleus–nucleus collisions at (4.1–4.5) AGeV/c

A detailed study of the centrality dependence of pseudo-rapidity distribution has been carried out for [Formula: see text]O-emulsion interactions at 4.5[Formula: see text]AGeV/c and [Formula: see text]Ne-emulsion interactions at 4.1[Formula: see text]AGeV/c using nuclear emulsion track detector. Depending on the values of the total charges or sum of the charges of noninteracting projectile fragments, event samples were classified into four centrality classes. Maximum pseudo-rapidity density, average pseudo-rapidity values, moments of pseudo-rapidity distribution along with skewness and kurtosis of the distributions have been investigated for different centrality classes.

An investigation of projectile helium fragments in high-energy nucleus–nucleus interactions

A detailed study on the multiplicity distribution of helium (He) fragments emitted in projectile fragmentation of 22Ne, 28Si, and 32S projectiles on interactions with H, CNO, and AgBr targets in a nuclear emulsion track detector has been presented at an incident momentum of (4.1–4.5) AGeV/c. The percentage of events with He fragments increases with increase in projectile mass for all three targets. Studies of multiplicity moments, dispersion of multiplicity distribution, and the investigation of dynamical fluctuations of the projectile He fragments have also been carried out.

Muon radiography method for fundamental and applied research

This paper focuses on the basic principles of the muon radiography method, reviews the major muon radiography experiments, and presents the first results in Russia obtained by the authors using this method based on emulsion track detectors.

Experiments on muon radiography with emulsion track detectors

Muon radiography is a method of study the internal structure of large natural and industrial objects based on sensing an object with a flux of cosmic muons with their subsequent registration and analysis of the pattern of their dispersion, or conplete (or partial) absorption. The Lebedev Physical Institute of the Russian Academy of Sciences and the Skobeltsyn Institute of Nuclear Physics of Moscow State University have started a series of muon radiography experiments with nuclear emulsion detectors. As a result, the optimal conditions for experiment arrangement have been determined, algorithms of data processing have been worked out, and peculiarities of the method have been ultimately investigated.

Test Experiments on muon radiography with emulsion track detectors in Russia

In Russia, the Lebedev Physical Institute of the Russian Academy of Sciences and the Skobeltsyn Institute of Nuclear Physics of Moscow State University are starting a series of pilot muon radiography exper-iments with nuclear emulsion detectors to study the interior structure of large-scale natural and industrial objects. As a result, the optimal conditions for experimental organization have been determined, algorithms of data processing have been worked out, and peculiarities of the method have been ultimately investigated. Here we present the experimental data, including field observations (in the mine of Geophysical department of Russian Academy of Sciences) confirming the availability of the method with track detectors on the base of nuclear emulsions with uniquely high spatial resolution, providing their high-tech automated processing.

Test Experiments on Muon Radiography with Emulsion Track Detectors in Russia

Lebedev Physical Institute (LPI RAS) and Skobeltsyn Institute of Nuclear Physics MSU (SINP MSU) have started the series of test muon radiography experiments in Russia. These experiments are aimed at determination of the optimal conditions of the setup, elaboration of algorithms for data processing and the study of the method peculiarities. The final goal of the method development is drafting of monitoring systems for natural and technological objects which condition may be a threat for the population, infrastructure or environment.

Prospects of the study of geological structures by muon radiography based on emulsion track detectors

For the first time in Russia, researchers of the Lebedev Physical Institute and Skobeltsyn Institute of Nuclear Physics perform test experiments for studying the internal structure of large natural and industrial objects by the muon radiography method using the emulsion technique. The used technique is based on the high penetrability of cosmic muons and implies the detection of the attenuation of their flux passed through the object under study using nuclear photoemulsions with a uniquely high spatial resolution. The results of the first test experiment are presented, which confirm the promising application of the method when using emulsion track detectors and their subsequent hi-tech automated processing.

Simulation of tau neutrino interaction in an emulsion track detector

Simulation of the interactions between tau neutrinos ντ and the material of the emulsion track detector using Geant4 software is described. The purpose of the work is to generate artificial events and to estimate, on their basis, the reconstruction accuracy for the geometric parameters (vertex coordinates, impact parameters, and track kink angles) and distributions of these parameters used in the selection criteria of the OPERA experiment.

Track sensitivity and maximum exposure density of nuclear emulsion in the controlled mode

The paper presents the results of measurements of track sensitivity of controllable a “primitive” nuclear emulsion for particles with different ionization densities. In the pulse electric field the probability of such emulsion microcrystal development reaches 0.85–1 for particles with ionization density I = (2–5) · Ir (Ir is the minimum ionization density). The evaluated minimum threshold energy needed for development of primitive emulsion microcrystals is about 35keV. It is shown that the Monte Carlo simulation can be used with success for evaluating the maximum exposure density of a controllable emulsion track detector.

Track sensitivity and maximum exposure density of nuclear emulsion in the controlled mode

The paper presents the results of measurements of track sensitivity of controllable a “primitive” nuclear emulsion for particles with different ionization densities. In the pulse electric field the probability of such emulsion microcrystal development reaches 0.85–1 for particles with ionization density I = (2–5) · I r ( I r is the minimum ionization density). The evaluated minimum threshold energy needed for development of primitive emulsion microcrystals is about 35keV. It is shown that the Monte Carlo simulation can be used with success for evaluating the maximum exposure density of a controllable emulsion track detector.

Measurement of charge of projectile fragments. Search for fractionally charged projectile fragments

Measurement of charges (1⩽Z⩽3) of the projectile fragments in relativistic heavy-ion collisions (16O-emulsion at 2.1A GeV/c per nucleon) was carried out by the measurement of lacunarity (L) of the track structure in nuclear emulsion track detector. The lacunarity values obtained for eight tracks cannot be explained if one assumes that they are integrally charged.

Controlled detection of charged particles in silver-bromide emulsions

Results are presented of an investigation of the effect of a pulsed electric field with intensity ~ 10 6 V/cm on nuclear and photographic emulsions with the purpose of trying to create an emulsion track detector with a controlled sensitivity. A controlled regime of detection of fast charged particles resulting in an increase in track density by a factor of 50 and a memory time of 14 μs has been attained in an experimental low-sensitive nuclear emulsion.