Nuclear Emulsion Research Articles

Highlights of Unstable States in Relativistic Dissociation of Light Nuclei in Nuclear Emulsion

Highlights of Unstable States in Relativistic Dissociation of Light Nuclei in Nuclear Emulsion

New high-precision measurement system for electron–positron pairs from sub-GeV/GeV gamma-rays in the emulsion telescope

The GRAINE project observes cosmic gamma-rays, using a balloon-borne emulsion-film-based telescope in the sub-GeV/GeV energy band. We reported in our previous balloon experiment in 2018, GRAINE2018, the detection of the known brightest source, Vela pulsar, with the highest angular resolution ever reported in an energy range of >80MeV. However, the emulsion scanning system used in the experiment was designed to achieve a high-speed scanning, and it was not accurate enough to ensure the optimum spatial resolution of the emulsion film and limited the performance. Here, we report a new high-precision scanning system that can be used to greatly improve the observation result of GRAINE2018 and also be employed in future experiments. The scanning system involves a new algorithm that recognizes each silver grain on an emulsion film and is capable of measuring tracks with a positional resolution for the passing points of tracks of almost the same as the intrinsic resolution of nuclear emulsion film (∼70 nm). This resolution is approximately one order of magnitude smaller than that obtained with the high-speed scanning system. With this scanning system, an angular resolution for gamma-rays of 0.1° at 1GeV is expected to be achieved. Furthermore, we successfully combine the new high-precision scanning system with the existing high-speed scanning system, enabling the high-speed and high-precision measurements. Employing these techniques, we reanalyze the gamma-ray events detected previously by only the high-speed scanning system in GRAINE2018 and obtain an about three times higher angular resolution (0.22°) in the 500–700MeV energy range. Adopting this technique in future observations may provide new insights into the gamma-ray emission from the Galactic center region and may realize polarization measurements of high-energy cosmic gamma-rays.

From dark matter searches to proton therapy: Measuring target fragmentation with nanometric nuclear emulsions

The DAMON (Direct meAsureMent of target fragmentatiON) project aims to explore the use of Nano Imaging Trackers (NITs) for the first direct measurement of target fragmentation caused by proton beams in cancer treatment. NITs are fine-grained nuclear emulsion films that offer a spatial resolution at the nanometric scale. DAMON’s pilot test exposed a NIT-based detector to 211 MeV protons, paving the way for the first study of target fragmentation in direct kinematics. In this paper the preliminary results regarding the multiplicity of the fragments and their track lengths are reported.

Cosmic rays, radiocarbon and the beginning of high-energy particle physics: Marietta Blau and the “disintegration stars”

Abstract This brief review describes the discovery of cosmic rays by Victor Hess from the Vienna Radium Institute and the later contribution of Marietta Blau through her observation of “disintegration stars” in photographic emulsion plates exposed to cosmic-ray bombardment. Marietta Blau, a nearly forgotten cosmic-ray pioneer from the Vienna Radium Institute, developed the nuclear emulsion technique for studying nuclear reactions, eventually discovering the disintegration of nuclei through high-energy cosmic rays. Blau survived the Holocaust by escaping to Mexico City from 1939 to 1944. Starting in 1948 at Columbia University, later as a staff member of Brookhaven National Laboratory and then University of Miami, she performed fundamental and original research with nuclear emulsions exposed to 3-GeV protons at the Brookhaven Cosmotron and to 6-GeV protons at the Berkeley Bevatron. Blau returned to Vienna in 1960, where at the Radium Institute a classical β-decay counting facility for radiocarbon dating had been installed, which was finally superseded by the Vienna Environmental Research Accelerator (VERA), a modern versatile accelerator mass spectrometry facility.

Adaptation of the Pavicom-1 Automated Scanning Facility for Processing Nuclear Emulsions of the SND@LHC Experiment

Adaptation of the Pavicom-1 Automated Scanning Facility for Processing Nuclear Emulsions of the SND@LHC Experiment

Resetting of nuclear emulsions by erasing noises formed during storage: Mechanism and application

The resetting of a nuclear emulsion is one of the most important technologies for the start of its new era and was realized in the OPERA experiment. Since the OPERA experiment was carried out several months after the production of its nuclear emulsion layers, AgBrI grains in the layers were exposed to ionizing particles before experiments, and formed latent image centers as noises on their surfaces. The technology to reset the emulsion layers was needed and achieved by the refresh treatment, which erased the latent image centers by enhancing their fading under the condition with high humidity at high temperature in the presence of 5-methyl-benzotriazole (5-MBT). While the treatment is being applied to other experiments with nuclear emulsions, its mechanism has not yet been made clear. Taking into account the fact that 5-MBT played a central role for the effect of the treatment, this study has been undertaken to reveal the mechanism of the treatment by focusing on the behavior of 5-MBT. It has been revealed that the irreversible phase transition of 5-MBT for the formation of epitaxial silver salt nanoparticles of 5-MBT anions at the corners of the AgBrI grains during the treatment enhances the detachment of a silver ion from a latent image center on a site with electric charge of +1/2, thus making the center to bear the electric charge of −1/2 and unstable against oxidation. Ideas have been proposed to make the treatment available for other experiments with nuclear emulsions.

Charge measurement with nuclear emulsions spectrometers for hadron therapy fragmentation cross section measurements with the FOOT experiment

Experimental data concerning projectile and target fragmentation is limited, increasing the uncertainty on the dose in the entrance channel in particle therapy treatments. The FOOT experiment measures nuclear fragmentation cross sections with two complementary detectors. The performance of the FOOT nuclear emulsion detectors in identifying the charge of nuclear fragments has recently been studied using 16O beams at 200 and 400MeV/n, directed at carbon and polyethylene targets. This work extends the previous analysis, comparing experimental data and FLUKA Monte Carlo predictions, focusing on the angular distribution and relative abundances of fragments with Z≤5 originating from the interactions of a 400MeV/n oxygen beam with a carbon target.

Nuclear emulsion film production system for experiments in full-area scanning and analysis era

Research utilizing the sub-micron three-dimensional spatial resolution of nuclear emulsion detectors has been expanding in various fields, triggered by the development of automated emulsion scanning technology. This paper describes a new production system capable of supplying several thousand square meters of nuclear emulsion film per year. The development and introduction of improved emulsion gel, knife coating, and drying equipment have enabled the mass production of double-side coated nuclear emulsion films with thick emulsion layers suitable for full-area scanning and analysis. This system has played an essential role in numerous nuclear emulsion experiments.

Study of secondary charged particles produced in 12C-emulsion interactions at 4.5A GeV/c

This paper deals with the interactions of [Formula: see text]C-nucleus with the nuclear emulsion at 4.5[Formula: see text]A[Formula: see text]GeV/c, focused on distributions of multiplicity and the variation of the average multiplicities for secondary charged particles (black, gray, shower, and heavy particles) for the events released from these interactions. These averages have been calculated based on a model of modified cascade evaporation. A comparison has been made between the average multiplicities of the charged secondary particles produced from [Formula: see text]C and others from projectiles that interact with the nuclear emulsion at different energies, this comparison of [Formula: see text]C with other projectiles shows the fluctuations of the values of the average shower with gray for [Formula: see text]O and [Formula: see text]Si interactions occurring somewhat faster. The average number of shower, gray particles increases with the increasing mass number of the projectile Ap, except for black particles, which are nearly constant. The correlations of the average multiplicities for the different charged secondary particles are discussed. There is strong linear dependence in the correlations of average particles of shower, compound, and heavy on gray particles. The results of experimental and theoretical data were also verified with recent analysis data and new observations and were found to be consistent. Moreover, the results indicate that the residual target nucleus may have reached a temperature and constant excitation energy at a certain value for shower particles. The excess amount of energy at higher values of shower particles may be pumped into the system, and this energy may be expended during a transition of phase in the target nucleus system. The theoretical calculation results show good agreement with experimental data.

Some Characteristics of Relativistic Secondary Charged Particles Produced in 7Li Interaction with Nuclear Emulsion

Some Characteristics of Relativistic Secondary Charged Particles Produced in 7Li Interaction with Nuclear Emulsion

Reconstruction of 400 GeV/c proton interactions with the SHiP-charm project

The SHiP-charm project was proposed to measure the associated charm production induced by 400 GeV/c protons in a thick target, including the contribution from cascade production. An optimisation run was performed in July 2018 at CERN SPS using a hybrid setup. The high resolution of nuclear emulsions acting as vertex detector was complemented by electronic detectors for kinematic measurements and muon identification. Here we present first results on the analysis of nuclear emulsions exposed in the 2018 run, which prove the capability of reconstructing proton interaction vertices in a harsh environment, where the signal is largely dominated by secondary particles produced in hadronic and electromagnetic showers within the lead target.

Water holding-capacity and flavor improvement of prepared meat patties induced by magnetic field-assisted marinating and preheating

Magnetic field (MF)-assisted technology is considered a potentially effective approach to improve the edible quality of meat products. This study aims to investigate various parameters (0 mT–4.5 mT) of MF-assisted marinating and preheating processes on the water-holding capacity and flavor of prepared meat patties. Analyzing cooking loss, low-field nuclear magnetic resonance, emulsion stability, and rheological properties confirmed that the water-holding capacity of meat patties rises initially and then falls with increasing MF strength during two processes (marinating and preheating processes). Furthermore, MF-assisted processing boosts sulfur compounds production in meat patties, resulting in higher concentrations of keto alcohols such as 2-heptanone, ethanol, and amyl alcohol, which contribute positively to the flavor and sensory properties. Overall, an appropriate MF intensity with 3.0 mT for 3 h at marinating and with 4.5 mT for 45 min at preheating could enhance the water-holding capacity and flavor of prepared meat patties, indicating promise for the meat industry.

Multiplicity correlation of fast target protons and projectile fragments for the events produced in the interaction of 84Kr nuclei with emulsion nuclei at 1 A GeV

It has become obvious that one crucial aspect in understanding high energy nuclear reactions is the fragmentation of colliding nuclei. The nuclear emulsion is a 4[Formula: see text] detector that makes it simple to identify and quantify the charges of projectile fragments. In this work, we study the multiplicity distribution and angle distributions of single, double charge projectile fragments, fast target protons (gray particle) as well as their correlation for the events produced in the interactions of [Formula: see text] with emulsion nuclei at 1[Formula: see text]A[Formula: see text]GeV. We also study the target-dependent angle distribution of gray particles. The results are compared with other experimental data as per availability. This analysis shows that multiplicity distributions have a remarkable link between the projectile and target fragmentation processes.

Measurement of the muon flux at the SND@LHC experiment

The Scattering and Neutrino Detector at the LHC (SND@LHC) started taking data at the beginning of Run 3 of the LHC. The experiment is designed to perform measurements with neutrinos produced in proton-proton collisions at the LHC in an energy range between 100 GeV and 1 TeV. It covers a previously unexplored pseudo-rapidity range of 7.2<η<8.4\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$7.2<\\eta <8.4$$\\end{document}. The detector is located 480 m downstream of the ATLAS interaction point in the TI18 tunnel. It comprises a veto system, a target consisting of tungsten plates interleaved with nuclear emulsion and scintillating fiber (SciFi) trackers, followed by a muon detector (UpStream, US and DownStream, DS). In this article we report the measurement of the muon flux in three subdetectors: the emulsion, the SciFi trackers and the DownStream Muon detector. The muon flux per integrated luminosity through an 18×\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ imes $$\\end{document}18 cm2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{2}$$\\end{document} area in the emulsion is: 1.5±0.1(stat)×104fb/cm2.\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\begin{aligned} 1.5 \\pm 0.1(\ ext {stat}) \ imes 10^4\\,\ ext {fb/cm}^{2}. \\end{aligned}$$\\end{document}The muon flux per integrated luminosity through a 31×\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ imes $$\\end{document}31 cm2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{2}$$\\end{document} area in the centre of the SciFi is: 2.06±0.01(stat)±0.12(sys)×104fb/cm2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\begin{aligned} 2.06\\pm 0.01(\ ext {stat})\\pm 0.12(\ ext {sys}) \ imes 10^{4} \ ext {fb/cm}^{2} \\end{aligned}$$\\end{document}The muon flux per integrated luminosity through a 52×\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ imes $$\\end{document}52 cm2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{2}$$\\end{document} area in the centre of the downstream muon system is: 2.35±0.01(stat)±0.10(sys)×104fb/cm2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\begin{aligned} 2.35\\pm 0.01(\ ext {stat})\\pm 0.10(\ ext {sys}) \ imes 10^{4}\\,\ ext {fb/cm}^{2} \\end{aligned}$$\\end{document}The total relative uncertainty of the measurements by the electronic detectors is 6%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\%$$\\end{document} for the SciFi and 4%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\%$$\\end{document} for the DS measurement. The Monte Carlo simulation prediction of these fluxes is 20–25%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\%$$\\end{document} lower than the measured values.

Knowledge of doubly strange hypernuclei and experimental prospect

Experiments for doubly strange hypernuclei with nuclear emulsion have been performed at KEK and J-PARC for the past 30 years. From detected 47 events, the characteristics were understood for Λ-Λ interaction to be weakly attractive, linear mass number dependence for two Λs binding energy, presence of Ξ hypernucleus, and it can be seen for something like the level structure of 15ΞC. Developing scanning method, so-called overall-scanning method, probably presents more rich information on not only doubly strange hypernuclei but also single-Λ hypernuclei.

Directional Dark Matter Search with Super-Resolution Nuclear Emulsion

Directional Dark Matter Search with Super-Resolution Nuclear Emulsion

First Emulsion γ-Ray Telescope Imaging of the Vela Pulsar by the GRAINE 2018 Balloon-borne Experiment

We are developing the Gamma-Ray Astro-Imager with Nuclear Emulsion project, designed for 10 MeV–100 GeV cosmic γ-ray observations with a high angular resolution (5′/0.°08 at 1–2 GeV) and a polarization-sensitive large-aperture (∼10 m2) emulsion telescope for repeated long-duration balloon flights. In 2018, a balloon-borne experiment was carried out in Australia with a 0.38 m2 sensitive area and a flight duration of 17.4 hr, including 6.7 hr of Vela observations. Significant improvements compared with the 2015 balloon-borne experiment were achieved by a factor of 5, including both an increase in effective area × time and a reduction in the background contribution. We aimed to demonstrate the telescope’s overall performance based on detection and imaging of a known γ-ray source, the Vela pulsar. A robust detection of the Vela pulsar was achieved with a 68% containment radius of 0.°42, at a significance of 6σ, at energies above 80 MeV. The resulting angular profile is consistent with that of a pointlike source. We achieved the current best imaging performance of the Vela pulsar using an emulsion γ-ray telescope with the highest angular resolution of any γ-ray telescope to date.

Super-resolution imaging for the detection of low-energy ion tracks in fine-grained nuclear emulsions

We propose a new wide-field imaging method that exploits the Localized Surface Plasmon Resonance phenomenon to produce super-resolution images with an optical microscope equipped with a custom design polarization analyzer module. In this paper we describe the method and apply it to the analysis of low-energy carbon ion tracks implanted in a nuclear emulsion film. The result is then compared with the measurements of the same tracks carried out at an electronic microscope. The images set side by side show their close similarity. The resolution achieved with the current microscope setup is estimated to be about 50 nm.

Nuclear Emulsion Detectors for the Muography of Underground Structure of Holy Dormition Pskov-Caves Monastery

Nuclear Emulsion Detectors for the Muography of Underground Structure of Holy Dormition Pskov-Caves Monastery

GEOCHEMICAL VIEW ON “INOFFENSIVE” DEPLETED URANIUM

The interaction of alpha radiation from UO2 micro- and nanoparticles (uraninite) with the substance was visualized using alpha-autoradiography data on A-2 thick-layer nuclear photographic emulsions. The spherical area of action of alpha particles around UO2 micrograins, up to 100 microns in size, is a deeply transformed substance with a high density of radiation defects. The translation of these results on a living organism leads to the conclusion about the specific type of impact of micro- and nanoparticles of depleted uranium, in which prolonged internal irradiation in small doses of the whole organism is combined with catastrophically high doses of alpha radiation in local zones, near micro- and nanoparticles UO2.