Solar Neutron and Gamma-ray Spectrrocopic Mission

Kazutaka Yamaoka ¹ Hiroyasu Tajima ¹ Kikuko Miyata ² Takaya Inamori ² Yoshinori Sasai ¹ Hiroaki Kawahara ³ Ji Hyun Park ^1,2 Kazuhiro Nakazawa ^3,4 Satoshi Masuda ¹ Koji Matsushita ⁵ Kazuya Itoh ⁵ Daiki Nobashi ^1,3 Hiromitsu Takahashi ⁶ Kyoko Watanabe ⁷

¹Institute for Space-Earth Environmental Research (ISEE), Nagoya University, Nagoya, Aichi, Japan
²Department of Aerospace Engineering, Graduate School of Engineering, Nagoya Univesity, Nagoya, Aichi, Japan
³Department of Particle Physics and Astronomy, Graduate School of Science, Nagoya University, Nagoya, Aichi, Japan
⁴Kobayashi-Maskawa Institute for the Origin of Particle and the Universe (KMI), Nagoya University, Nagoya, Aichi, Japan
⁵Technical Center, Nagoya University, Nagoya, Aichi, Japan
⁶Department of Physical Science, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan
⁷Department of Earth and Ocean Sciences, National Defence Academy of Japan, Yokosuka, Kanagawa, Japan

Solar neutron observations are very important on understanding of particle acceleration mechanism in the Sun. However, previous ground-based observations with large area telescope (~10 m2)at high latitude are not sensitive to solar neutrons due to attenuation in the earth atomsphere and roughly 10 detection since its discovery in 1980 (Chupp et al. 1982). From space, the SEDA-AP instrument with much smaller area (100 cm2) onboard the International Space Station (ISS) monitored solar neutrons including charged particles, and successfully detected more than 30 detection since its launch in 2009 (Muraki et al. 2014). Unfortunately the SEDA-AP operation was stopped on March 2018. To overcome situation for no mission dedicated for solar neutrons, we have designed and developed a solar neutron and gamma-ray detector for a 3U cubesat with a size of 30x10x10 cm. Actually we launched the 50-kg class ChubuSat-2 satellite for solar neutron observations on February 2016 (Yamaoka et al. 2016), and have now been modifying it to a 3U cubesat application. The solar neutron and gamma-ray detector consists of multi-layered plastic scintillator bars, and GAGG(Ce) scintillator array, and both of them are read out with silicon photo-multipliers (Si PMs). More than 600 signals from Si PMs are processed by IDEAS ASICs. In this paper, we will describe details of the detector and performance of its breadboard model (BBM).

Kazutaka Yamaoka

Nagoya University