Latest nuclear emulsion technology Rokujo, Hiroki; Kawahara, Hiroaki; Komatani, Ryosuke ...
EPJ Web of conferences,
2017, Letnik:
145
Journal Article
Recenzirano
Odprti dostop
Nuclear emulsion is a extremely high-resolution 3D tracking detector. Since the discovery of the pion by C.F. Powell et al. in 1946, experiments with nuclear emulsions have contributed to the ...development of particle physics. (e.g. the OPERA collaboration reported the discovery of νμ * ντ oscillations in appearance mode in 2015) The technology of nuclear emulsion still keeps making progress. Since 2010, we have introduced a system of nuclear emulsion gel production to our laboratory in Nagoya University, and have started self-development of the new gel, instead of from the photographic film companies. Moreover, a faster automated emulsion scanning system is developed. Its scanning speed reaches 4000 cm2/h, and the load for analyzing becomes more and more lighter. In this presentation, we report the status of nuclear emulsion technologies for cosmic ray experiments.
Nuclear emulsion is a extremely high-resolution 3D tracking detector. Since the discovery of the pion by C.F. Powell et al. in 1946, experiments with nuclear emulsions have contributed to the ...development of particle physics. (e.g. the OPERA collaboration reported the discovery of νμ * ντ oscillations in appearance mode in 2015) The technology of nuclear emulsion still keeps making progress. Since 2010, we have introduced a system of nuclear emulsion gel production to our laboratory in Nagoya University, and have started self-development of the new gel, instead of from the photographic film companies. Moreover, a faster automated emulsion scanning system is developed. Its scanning speed reaches 4000 cm2/h, and the load for analyzing becomes more and more lighter. In this presentation, we report the status of nuclear emulsion technologies for cosmic ray experiments.
We are developing the GRAINE project, which consists of a 10 MeV–100GeV cosmic
$\gamma$
-ray observation with a precise (0.08
$^\circ$
at 1–2GeV) and polarization-sensitive (50% or below the minimum ...detectable polarization for the Vela pulsar above 100 MeV) large-aperture-area (
$\sim$
10m
$^2$
) emulsion telescope, by repetitive long duration balloon flights. In 2015, we performed a Japan–Australia JAXA collaborative balloon experiment at the Alice Springs balloon-launching station. The telescope had a 3780cm
$^2$
aperture and was aloft for a total of 14.4h. The experiment aims to detect the well-known bright Vela pulsar
$\gamma$
-ray source and thereby demonstrate the overall performance of the emulsion
$\gamma$
-ray telescope. The design, improvements, and preparations as well as the 2015 balloon experiment are described in this paper. Analysis of the data from this experiment is ongoing.
Scoria cone is one of the basic forms of volcanoes, and clarifying its detailed internal structure and magma movement during its formation is important for understanding the nature of eruptions and ...also for volcanic disaster mitigation. We conducted a multi-directional muographic survey of the Omuroyama scoria cone, Japan, in order to determine the three-dimensional density structure of the scoria cone. We used a nuclear emulsion detector optimized for multi-directional muography that was installed at 11 sites around the volcano. Muon tracks recorded on emulsion films were read with a high-speed automated readout system. We obtained the three-dimensional density structure by applying a linear inversion to the muographic images, and evaluated the uncertainties. High-density zones were detected in scoria cone. Based on these observations and detailed topographic and geological constraints, we infer that high-density zones are the central, highly welded vent of the scoria cone, three-directional radial dikes extending from the central vent, respectively. We also infer that an E-W-trending dike fed a small lava flow, and that a SSE-NNW-trending dike caused a small flank eruption and produced a crater on the flank of the cone. Our results visualize the three-dimensional internal structure of volcanoes with novel resolution, and thereby demonstrate that the formation process of volcanoes can be discussed in detail. Since it has been difficult to directly detect such clear visualization of the internal structures and eruptive processes in the past, multi-directional muography has resulted in providing one hope for understanding volcanic activity.
We report the first direct observation of neutrino interactions at a particle collider experiment. Neutrino candidate events are identified in a 13.6 TeV center-of-mass energy pp collision dataset of ...35.4 fb^{-1} using the active electronic components of the FASER detector at the Large Hadron Collider. The candidates are required to have a track propagating through the entire length of the FASER detector and be consistent with a muon neutrino charged-current interaction. We infer 153_{-13}^{+12} neutrino interactions with a significance of 16 standard deviations above the background-only hypothesis. These events are consistent with the characteristics expected from neutrino interactions in terms of secondary particle production and spatial distribution, and they imply the observation of both neutrinos and anti-neutrinos with an incident neutrino energy of significantly above 200 GeV.
A method for the measurement of energetic DT neutron tails resulting from knock-on alpha particles is needed to study plasma physics in a fusion reactor. A nuclear emulsion offers satisfactory ...performance for the detection of fast neutrons and measures their energies using three-dimensional tracking information. However, the time required for analysis forms a bottleneck in the implementation of this measurement technique. Recently, the analysis speed of nuclear emulsion has dramatically increased because of our development. In this report, we propose the use of nuclear emulsion for DT burning plasma diagnostics using the latest analysis technology and the validation of the methodology. In addition, we discuss the prospects of improving nuclear emulsion technologies for fusion plasma diagnostics.
PDF
