July 29, 2015 to August 6, 2015
World Forum
Europe/Amsterdam timezone

Latest emulsion detector for cosmic ray observation: high sensitive emulsion film and high speed readout system

Aug 1, 2015, 3:30 PM
Amazon Foyer (World Forum)

Amazon Foyer

World Forum

Churchillplein 10 2517 JW Den Haag The Netherlands
Board: 165
Poster contribution CR-IN Poster 2 CR


Hiroki ROKUJO (Nagoya University)


Nuclear emulsion is a high resolution 3D tracking device. 0.2 $\mu$m AgBr crystals penetrated by a charged particle grow into 0.8 $\mu$m silver grains which can be observed as a track by a microscope via chemical development process. The recent fully automated readout systems enabled not only high resolution measurements but also large-scale experiments (accelerator experiments, balloon-borne experiments, cosmic ray muon radiography, and so on). Since 2010, circumstances of the emulsion detector has drastically changed. We have introduced a system of nuclear emulsion gel production to the laboratory in Nagoya University, Japan, and have started self-development and supply of the new, ambitious gel, instead of the photographic film companies. We have also developed a next-generation readout system, Hyper Track Selector (HTS). The scanning speed is designed to 0.9 m$^{2}$/h (100 times faster than that of the current system). Gamma-Ray Astro-Imager with Nuclear Emulsion (GRAINE) is a project of cosmic gamma-ray observation using the balloon-borne emulsion detector. The angular resolution of the emulsion gamma-ray telescope (0.08$^{\circ}$ @ 1-2 GeV) is one order of magnitude better than that of the Fermi-LAT. In addition, It has the polarization sensitivity using the pair creation mode. Search for exotic particles and measurement of short-lived particle production rate in cosmic rays at balloon altitudes will be also conducted. In the GRAINE 2nd balloon-borne experiment in 2015 May, 50 m$^{2}$ of the new high sensitive emulsion films are used for the middle-scale gamma-ray telescope (aperture area 3600 cm$^{2}$) which we demonstrate the imaging performance by.  We present the status of the latest emulsion detector and readout system based on results of performance tests conducted for the GRAINE balloon-borne experiment in 2015.
Registration number following "ICRC2015-I/" 846
Collaboration -- not specified --

Primary author

Hiroki ROKUJO (Nagoya University)


GRAINE collaboration (GRAINE collaboration)

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