Abstract
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 m
2
) emulsion telescope for repeated long-duration balloon flights. In 2018, a balloon-borne experiment was carried out in Australia with a 0.38 m
2
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 6
σ
, 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.
Abstract
The Gamma-Ray Astro-Imager with Nuclear Emulsion (GRAINE) project is aimed at the precise observation of astronomical gamma-ray sources in the energy range of 10 MeV–100 GeV using a ...balloon-borne telescope utilizing a nuclear emulsion, which can help realize precise imaging with high angular resolution (1.0○ at 100 MeV), polarization sensitivity, and large aperture area (10 m2). In 2018, the third balloon experiment was carried out as a demonstration of the detection of the brightest known astronomical gamma-ray source, the Vela pulsar, with an aperture area of 0.38 m2. In these data, some gamma rays were produced by the π0 → 2γ decay, which was caused by the hadronic interactions of cosmic rays in the detector. These could be used to calibrate the reconstructed angle, energy, and so on. In this study, we establish a method of searching for hadronic interactions and concomitant gamma rays with high statistics and purity. Our analysis indicates that the performance of our detector for gamma rays is as expected in wide incidence angle and energy ranges. We plan to commence scientific observations using the proposed system with the verified high angular resolution and largest aperture area in 2022 or later.
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.
Nuclear emulsion plates for studying elementary particle physics as well as cosmic ray physics are very powerful tracking tools with sub-micron spatial resolutions of charged particle trajectories. ...Even if gamma rays have to be detected, electron-positron pair tracks can provide precise information to reconstruct their direction and energy with high accuracy. Recent developments of emulsion analysis technology can digitally handle almost all tracks recorded in emulsion plates by using the Hyper Track Selector of the OPERA group at NAGOYA University. On the other hand, the potential of time resolutions have been equipped by emulsion multilayer shifter technology in the GRAINE (Gamma Ray Astro-Imager with Nuclear Emulsion) experiments, the aims of which are to detect cosmic gamma rays such as the Vela pulsar stellar object by precise emulsion tracking analysis and to study cosmic ray particle interactions and chemical compositions. In this paper, we focus on the subject of cosmic ray nuclei detection in the GRAINE balloon flight experiments launched at Alice Springs, Australia in May 2015.
Nuclear emulsion plates for studying elementary particle physics as well as cosmic ray physics are very powerful tracking tools with sub-micron spatial resolutions of charged particle trajectories. ...Even if gamma rays have to be detected, electron-positron pair tracks can provide precise information to reconstruct their direction and energy with high accuracy. Recent developments of emulsion analysis technology can digitally handle almost all tracks recorded in emulsion plates by using the Hyper Track Selector of the OPERA group at NAGOYA University. On the other hand, the potential of time resolutions have been equipped by emulsion multilayer shifter technology in the GRAINE (Gamma Ray Astro-Imager with Nuclear Emulsion) experiments, the aims of which are to detect cosmic gamma rays such as the Vela pulsar stellar object by precise emulsion tracking analysis and to study cosmic ray particle interactions and chemical compositions. In this paper, we focus on the subject of cosmic ray nuclei detection in the GRAINE balloon flight experiments launched at Alice Springs, Australia in May 2015.
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