Emulsion Chamber Research Articles

First Results of Studying EAS Cores Using a High-Mountain Ionization Calorimeter

In high-altitude experiments to study the central cores of EAS at E0 ≳ 1016 eV (√s ≳ 5 TeV) using X-ray emulsion chambers and ionization calorimeters, phenomena such as the coplanarity of the arrival of the most energetic particles in super families of γ-rays and hadrons and a so-called Tien Shan effect (too slow absorption of cascades initiated by high-energy hadrons in the calorimeter) were observed. These effects could not be reproduced within the framework of theoretical models of the 80s and 90s. The coplanarity is explained via a process of coplanar generation of the most energetic secondary particles in interactions of super high-energy hadrons with nuclei of air atoms. Perhaps the Tien Shan effect could be explained using a high cross section for the generation of fragmentation-region charmed hadrons. To study these phenomena, a new set of detectors has been developed, including the world’s highest high-mountain ionization calorimeter, “Hadron-55”. This paper presents the initial experimental results.

The composition of cosmic rays according to the data on EAS cores

The main purpose of this work is to find the causes of the break of the cosmic ray spectrum at an energy of 3 PeV, which is called the knee. The solution of the problem is associated with the determination of the nuclear composition of cosmic rays in the knee area. The conclusions of this work are based on the analysis of the characteristics of the EAS cores obtained using X-ray emulsion chambers. According to these data, a number of anomalous effects are observed in the knee region, such as scaling violation in the spectra of secondary hadrons, an excess of muons in EAS with gamma families and others. At the same energies equivalent to 1-100 PeV the laboratory system colliders show scaling behavior. So analysis of the data on the EAS cores suggests that the knee in their spectrum is formed by a component of cosmic rays of a non-nuclear nature, possibly consisting of stable (quasi-stable) particles of hypothetical strange quark matter, which named strangelets. This is the only model of the knee compatible with the magnetic rigidity of the nuclear spectra break R=100 TV. In fact, stranglets are stable heavy quasi-nuclei with a positive electric charge of Z=30-1000, so the mechanism of their acceleration coincides with the nuclear one. The break of the cosmic ray spectrum can be associated with a significantly larger mass of strangelets compared to nuclei.

Simulation of the Response of a Hybrid Detector Based on Scintillation Optical Fibers and an Emulsion Chamber

Simulation of the Response of a Hybrid Detector Based on Scintillation Optical Fibers and an Emulsion Chamber

Strange Quark Matter and the Astrophysical Nature of Anomalous Effects in 1–100 PeV Cosmic Rays

The composition of cosmic rays is of decisive importance for the determination of reasons for change in the slope of the spectra of extensive air showers (knee) at energies of 1–100 PeV. The characteristics of the extensive air showers, where the highest energy secondary hadrons are concentrated, have been analyzed. Some anomalous effects such as an increase in the absorption length of hadron showers, scaling violation in the spectra of secondary hadrons, an excess of muons in extensive air showers with gamma-ray families, the appearance of the halos, and the alignment of energy centers along a straight line are observed in X-ray emulsion chambers in the knee region. At the same energies equivalent to 1–100 PeV in the laboratory system, LHC and RHIC data demonstrate a scaling behavior of the hadron spectrum, which means that new nuclear processes are absent. These data imply that anomalies observed in cosmic rays are due to astrophysical reasons, i.e., changes in the composition of cosmic rays. The analysis of the data on the EAS cores suggests that the knee in their spectrum is formed by a nonnuclear component of cosmic rays, possibly consisting of particles of strange quark matter.

Interactions of Neutral Particles with Energies >7 TeV in Stratospheric X-Ray Emulsion Chambers

Interactions of Neutral Particles with Energies >7 TeV in Stratospheric X-Ray Emulsion Chambers

The rise of muon content in extensive air showers after the 3 PeV knee of the primary cosmic ray spectrum according to data of the Tien Shan mountain installation

We put together the experimental results on muon component of extensive air showers (EAS) which were gained with various techniques at the detector complex of the Tien Shan mountain station. According to this comparison, the problem of the EAS muon content in the range of primary cosmic ray energies (1–100)PeV seems to be more complicated than it was usually supposed. Generally, from the models of nuclear interaction it follows that the EAS which have produced gamma-hadron families in the Tien Shan X-ray emulsion chamber did preferably originate from interaction of the light cosmic ray nuclei, such that their muon abundance must be ∼1.5 times below an average calculated over all showers. In contrary, the experimental muon counts in the EAS with families demonstrate a (1.5–2)-fold excess above the average, and this difference starts to be observable in the showers with the energy above the 3PeV knee of the primary cosmic ray spectrum. Later on, the rise of muon production in EAS after the knee was confirmed at Tien Shan by another experiment on detection of the neutrons stemmed from interaction of cosmic ray muons. Thus, the results obtained by the two completely different methods do mutually agree with each other but contradict to the common models of hadron interaction.

Is There a Relationship between the Collider “Ridge” Effect and Particle Coplanarity in Gamma Ray–Hadron Families?

Proton–proton interactions are modeled using the FANSY 2.0 model to show that the “long-range ridge effect” discovered by the CMS collaboration at the LHC can be explained within a single physical process, along with the coplanarity in gamma-ray–hadron families observed in extensive atmospheric shower cores during experiments with X-ray emulsion chambers.

Estimation of the $$\boldsymbol{p+\textrm{He}}$$ Fraction in the Mass Composition of Primary Cosmic Radiation the Energy Range of $$\boldsymbol{E_{0}=1}$$–100 PeV according to Gamma-Ray Families Featuring Halo

The present article reports on an analysis of the properties that gamma-ray families featuring a halo exhibit in the cores of extensive air showers (EAS). The events under analysis were obtained in the XREC (x-ray emulsion chambers) PAMIR experiment, and the properties of these events were studied at distances extending up to about 10 cm from the EAS axis with a resolution of approximately 30 $$\mu$$ m. The investigation of the parameters of events in EAS cores by the halo method permitted analyzing the mass composition of primary cosmic radiation (PCR) at $$E_{0}=10$$ PeV and assessing the fraction of light nuclei in PCR, which depend only slightly on the model of EAS propagation through the atmosphere. From an analysis of gamma-ray families featuring a halo and multicenter halos obtained in the PAMIR XREC, it was found that the fraction of the ( $$p+\textrm{He}$$ ) component of PCR was about 40 $${\%}$$ . The properties of proton-induced EAS events detected at the Tien-Shan high-mountain Scientific Station (TShSS) were studied along with the KASCADE-Grande experimental data. On the basis of studying the dependence of the EAS age and $$N_{\mu}$$ on $$N_{e}$$ in the TShSS EAS (EAS $$+$$ XREC TShSS) data, it is concluded that PCR mass composition becomes heavier in the range of $$E_{0}=1$$ –100 PeV.

Observation of a Significant Flow of Neutral Galactic Particles in the Stratosphere at Energies in the Range of 1013–1015 eV

A reanalysis of experimental data from the RUssia-Nippon JOint Balloon (RUNJOB) emulsion experiment on the basis of a new method aimed at searches for primary galactic particles in events identified as those of nucleon-nucleus interaction confirmed the original result that consisted in the absence of a large number (about 50%) of tracks of incident particles. A comparative analysis of such events where there is a detected primary track and where there is no primary track was performed in terms of the energy, angular distribution, and depth of penetration into x-ray emulsion chambers (XREC). The hypothesis that a neutral component is present in cosmic rays at the XREC exposure level is discussed.

On the Dominant Role of Charm Production in the Forward Kinematic Region According to Cosmic-Ray Experiments

A phenomenon of abnormally weak absorption of very-high-energy cosmic-ray hadrons in lead is discussed. This phenomenon was first observed in Tien-Shan high-altitude experiments in hadronic cores of extensive air showers and has encouraged to introduce the hypothesis of a so-called long-flying or penetrating cosmic-ray component. A similar effect was detected later with deep uniform lead X-ray emulsion chambers (XREC) at the Pamirs. Experiments, which are sensitive to the production of charmed hadrons in the forward kinematic region (xLab ≳ 0.1), have been carried out at the Tien-Shan and Pamirs with exposing two-storey XRECs with large air gaps to prove explanation of the experimental results with high charm production cross section $${\sigma _{pp \to c\bar c}} \sim 8$$ at xLab ≳ 0.1 at ⟨ELab⟩ ∼ 75 TeV. This $${\sigma _{pp \to c\bar c}}$$ value makes it possible to reproduce the experimental hadron-absorption curve observed with XRECs, including curve’s bending at a depth of ∼70 c.u.

Development of a balloon-style pressure vessel gondola for balloon-borne emulsion gamma-ray telescopes

A gamma-ray telescope using nuclear emulsions allows observations of stellar objects in the 0.01–100 GeV energy region with high angular resolution, polarization sensitivity, and large aperture area. The Gamma-Ray Astro-Imager with Nuclear Emulsion (GRAINE) project is designed to enable high-precision observation of cosmic gamma rays through the use of balloon-borne emulsion telescopes. We have developed a balloon-style pressure vessel gondola for the GRAINE 2018 balloon-borne experiment. It enables us to maintain robust and vacuum-packed emulsion chambers even at balloon altitudes. The greater part of the vessel is made of membrane materials consisting of ultra-thin polyurethane-coated polyester fabric. It is lightweight and portable, and can be used to expand the mounting area of the detector, unlike mostly metal vessels. Moreover, the absorption of signal gamma rays and background gamma-ray production due to interactions between cosmic rays and the vessel can be minimized. The pressure vessel gondola, equipped with a 0.38-m2 emulsion telescope and other equipment, was launched on April 26, 2018. During the whole observation (17 h 21 m), the internal pressure was kept above 230 hPa. The GRAINE project will start scientific observation using enlarged telescopes and the pressure vessel gondola is planned to include an expansion of the mounting area of the detector to ∼10 m2 while following the design on the GRAINE 2018 model.

Detection of the Rare Interaction of a Neutral Particle with Energy Higher than 15 TeV in the Stratospheric X-ray Emulsion Chamber (According to the RUNJOB Experiment Data)

A rare event observed in a nuclear emulsion is reported. The RUNJOB Russian-Japanese balloon experiment detected the interaction of a high-energy neutral particle in a nuclear emulsion plate of an X-ray emulsion chamber exposed in 1999.

LPM effect in cosmic-ray electron observations with emulsion chambers

We have performed a series of cosmic-ray electron + positron observations using balloon-borne emulsion chambers since 1968, together with electron beam tests at CERN-SPS. In emulsion chamber experiments, we can measure the location of shower tracks in each emulsion plate with a precision of 1 μm. Because of the high position resolution, we can identify the first electron-positron pairs of electron-induced showers. The LPM effect predicts a reduction of amplitude for bremsstrahlung photon emission by a high-energy electron. It causes the optical depth of the first electron-positron pair to increase. From the measurements of the first pair depths with 200 GeV and 250 GeV beam electrons at CERN, and cosmic ray electrons + positrons from 400 GeV to 3 TeV (on average at 900 GeV), we found direct evidence of suppression of the bremsstrahlung cross section due to the LPM effect. In this work, we present the experimental results compared to analytic approximations and Monte-Carlo simulations.

Search for simultaneous and parallel cosmic gamma rays in the balloon-borne emulsion telescope experiments (GRAINE2015)

The emulsion chamber telescopes for observing 10 MeV - 100 GeV gamma rays have been developed by GRAINE (Gamma Ray Astro-Imager with Nuclear Emulsion) projects. We have performed the balloon filight in May, 2015 at Alice Springs, Australia, with 14.4 hours duration (including 11.5 hours of level flight) and 0.378 square meter aperture (GRAINE2015). GRAINE experiments utilized the multiple stage systems of emulsion films for timestamper of registered tracks.In this paper, we report the potential of GRAINE2015 experiments to detect the parallel and simultaneous cosmic gamma rays such as charged particles due to hadronic interactions, EAS (Extensive Air Shower) and GRBs (Gamma Ray Bursts).

SOME STORIES OF BRASIL-JAPAN COLLABORATION AND CHACALTAYA MOUNTAIN

An international cooperation, named Brasil-Japan Collaboration of Chacaltaya Emulsion Chamber Experiment (B-J Collaboration) exposed 2.35 × 108 m2.s, during the period 15thJun, 1962 till 10thMay, 1988. It corresponds to 22 'runs' on Cosmic Rays and in this figure are not included photosensitive material set in the lower part of the two-storied emulsion chamber. Although 3 more 'runs' occurred after 1988, they were not included either, because they were not yet properly measured and because they contain mixed Japanese and Russian films. Chacaltaya Mountain was firstly used in 1947 for 2 meson observations and π - μ decays. It was a wise choice not only for these observations but also for the B-J Collaboration and for the Alpaca Project, running at neighbouring sites. The main results observed by the B-J Collaboration are presented.

Investigation of abnormal absorption of cosmic-ray hadrons in lead calorimeters

A phenomenon of abnormally weak absorption of very high energy cosmic ray hadrons in thick lead blocks is discussed. This phenomenon was first observed in a Tien Shan high altitude experiment to study hadronic cores of extensive air showers (EAS) with a deep ionization calorimeter and encouraged researchers to introduce the hypothesis of the so-called long-flying or penetrating cosmic ray component. A similar effect was detected later with deep uniform lead X-ray emulsion chambers (XREC) at the Pamirs, which we discuss in detail. To establish the nature of the phenomenon we are have carried out dedicated experiments at the Tien Shan and at the Pamirs by exposing two-storey XRECs with large air gaps. According to detailed simulation of the chamber response, these experiments are very sensitive to the production of charmed hadrons in the forward kinematic region and can prove a hypothesis that the phenomenon under study can be explained on the assumption of very high values of charm particle production cross section at 〈ELab〉 ~ 75 TeV in the forward kinematic region at xLab≳ 0.1 which are near the upper limit of recent results of collider experiments, i.e., σpp→c¯c~ 8 mb. The same factor makes it possible to fit all the features of the experimental hadron absorption curve observed by means of deep uniform lead XRECs, including its bending at a depth of ~ 70 c.u.

Exotic model of the cosmic ray spectrum

A detailed study of the cores of extensive air showers (EAS) at mountain level (Tien-Shan 690 g/cm2) was carried out in the hybrid experiment HADRON. An analysis of the fine structure of the EAS spectrum in the energy region1015- 1017(knee) showed that there are two breaks in the spectrum. Along with the previously known break at an energy of 3 · 1015eV, a change in the slope of the EAS spectrum is observed at an energy slightly below 1017eV. In addition the use of a large X-ray emulsion chamber (XREC) as a detector of EAS cores allowed us to obtain several new results. An abnormal scaling violation in hadron spectra for Ne~ 107(E0~ 1016eV) means the existence of a penetrating component of non-nuclear origin. The conclusion about the non-nuclear origin of the penetrating component in the primary radiation of CR is confirmed by the data about the excess of muons in the EAS containing hadrons of maximum energies. It is assumed that the mass composition of primary cosmic radiation varies sharply at energies of 1015- 1016eV, where quasi-nuclei (strangelets) appear instead of nuclei. A new model of the mass composition of cosmic rays in the region of ultrahigh energies is proposed on this basis .

Способ определения углов в рентгеновских эмульсионных камерах

An analysis of the measurement procedure for the zenith and azimuth angles υ and φ in the X-ray emulsion chambers (XREC) of ADRON and PAMIR experiments is presented. Earlier, asymmetry was observed in distributions of azimuth angles of gamma and hadron families. A detailed analysis of methodological errors in measuring θ, φ angles allowed us to establish the causes of the distortion of azimuth angles distributions. There are two reasons: systematic errors in the measurement of zenith angles by MBS-2 microscopes, used both in the PAMIR experiment, and in the ADRON experiment, and the inclination of XREC based on the subsidence. Calculations showed that the total systematic error Δυ≈4 ° completely explains the observed azimuthal asymmetry. Formulas for correcting θ and φ angles are given. The recalculation of the angles by the indicated formulas showed that this corrects the distribution of  the azimuthal angles φ. The REC plane should be set relative to the horizontal with an accuracy of no worse than 1 degree in order to avoid distortion of the angular distributions.

Leading cluster approach to simulations of hadron collisions with GHOST generator

The model HDPM of CORSIKA has been updated and developed on the base of the recent measurements by ALICE, CMS, TOTEM, LHCb, LHCf... The new model, GHOST, involving a four-source production reproduces correctly the pseudo-rapidity distributions of charged secondaries and has been tested with the data in the mid and forward rapidity region, especially in the complex case of TOTEM, and also with the recent measurements of CMS, up to $ \sqrt s = 13\,{\rm{TeV}} $ (9.0 1016 eV in laboratory system). Special calculations have been devoted to the semi-inclusive data playing an important role in the cosmic ray simulation (fluctuations in earliest collisions, individual cascades measured at high altitude with high energy emulsion chambers). Taking into account the violation of KNO scaling, the negative binomial distribution (NegBin-expressed in terms of scaled elements) $ z = {n \mathord{\left/ {\vphantom {n {\bar {n}}}} \right. \kern-\nulldelimiterspace} {\bar {n}}} $ (n is the number of charged secondaries) has been used pointing out a possible asymptotic behaviour of total charged multiplicities at primary energies exceeding 40 TeV (8.5 1017 eV). Thus, larger reduction of the energies devoted to the leading cluster and very large multiplicity of secondary particles could suggest for EAS generated by primary protons a larger production of muons and a shower maximum at higher altitude.

Structural design and methodology for calculating the process of obtaining creamy-vegetable spreads

At present, work has been activated to develop and introduce healthy food products, reduce unit costs for the production of fat-and-oil products. In view of the multicomponent nature of many emulsion products and the difference in their aggregate state, there is a need to improve the design of equipment for production. The main indicators of the mixing process are the intensity and efficiency, as well as the energy consumption for the process. In the production of emulsions, the mixing efficiency can be characterized by the size of the forming particles of the dispersed phase, and the intensity - by the time of achieving the process goal - of a homogeneous structure with a multicomponent product, with minimal energy costs. In order to determine the time to achieve the result of the process, a dimensionless concentration can be used as an estimate. The effectiveness of mixing was evaluated by the dispersion of the emulsion. The investigations were carried out on a microscope "Micrometer 3" with an increase of 400 times. The average diameter of the emulsified particles was d = 5 10E-5 m, and the specific surface area of the emulsions was S = 1.2 10E5 1 / m. The proposed method for calculating the intensity and determining the mixing efficiency can be used to calculate the mixing of multicomponent emulsions of chemical and food products. The use of the proposed emulsion design makes it possible to optimize the process of thermomechanical action on raw materials, different in their physico-mechanical properties, by ensuring the maintenance of a given temperature regime in each of the emulsion chambers and the rational nature of the product movement; expand the scope of application due to the achieved universalization of the mixing mechanisms taking into account the physico-mechanical properties of the initial components; to obtain spreads balanced by fatty acid composition, consisting of a mixture of various components, by solving the problem of uniform distribution of the components of the mixture and the most rational temperature effect on them.