ICRC2015

GRAINE project: Flight data analysis of balloon-borne experiment in 2015 with emulsion gamma-ray telescope

30 Jul 2015, 15:30

1h

Mississippi Foyer (World Forum)

Board: 99

Poster contribution GA-IN Poster 1 GA

Speaker

Mr Keita OZAKI (Kobe University)

Description

GRAINE is a balloon-borne experiment to observe cosmic gamma-ray with precise angular resolution and polarization sensitivity. Main gamma-ray detector is nuclear emulsion which can record three dimensional charged particle track with sub-micron position accuracy. We use multi-stage shifter technique in order to give time information to penetrating tracks of nuclear emulsion. Arrival direction of gamma-ray can be reconstructed to the celestial sphere by combining attitude data from star camera. By measuring the beginning of electron-positron pair with nuclear emulsion, our telescope can be achieved gamma-ray angular resolution one order of magnitude better than Fermi-LAT, and polarization sensitivity. First balloon-borne experiment of GRAINE was performed in 2011 in TARF, Japan. Equipment of our telescope operated completely well and we measured atmosphere gamma-ray which are background when we observe cosmic gamma-ray. Second balloon-borne experiment will be done in May 2015 in Alice Springs, Australia by JAXA international program.　We aim to detect the Vela pulsar and also demonstrate the angular resolution best ever gamma-ray telescope. In this experiment, we overall use new type nuclear emulsion which are researching and developing at Nagoya University to improve sensitivity for charged particle. Emulsion films were transported to the University of Sydney by plane, and emulsion's handling such as resetting, drying, and packing will be performed there. For the second balloon experiment, the following equipment will be installed on a gondola with fabric pressure vessel: emulsion telescope, 3 star cameras, temperature meters, pressure meters, GPS systems, and batteries. After development of all emulsion films at University of Sydney, emulsion films will be scanned with fully automated readout system at Nagoya University. We will analyze using these scanned data to search gamma-ray events. Attitude data using star cameras will also be analyzed. Flight data analysis of GRAINE second balloon-borne experiment in 2015 is presented.