Solar neutron observations are important on understanding of nucleon acceleration mechanism in the Sun. However, previous ground-based observations with large area telescopes (∼10 m$^2$ ) at high latitude are not sensitive to solar neutrons due to attenuation in the earth atmosphere (roughly 10 detection since its discovery in 1980). From space, the SEDA-AP instrument with much smaller area (100 cm$^2$) onboard the International Space Station (ISS) monitored solar neutrons including charged particles, and successfully detected more than 30 detection since its launch in 2009. 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 30×10×10 cm. Actually we launched the 50-kg class ChubuSat-2 satellite for solar neutron observations on February 2016, and have now been adjusting it to a 3U CubeSat application, which is named as Solar Neutron and Gamma-ray Spectroscopy (SONGS) Mission. 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 ASICs provided by IDEAS. In this paper, we will describe details of the detector and performance of its breadboard model (BBM).
|Submission declaration||Redundant (overlaps with already published)|