Development of laboratory experimental system to clarify solar wind charge exchange mechanism with TES microcalorimeter

Significant fraction of the cosmic diffuse soft X-ray emission (0.1-1 keV) is caused by the Solar Wind Charge eXchange (SWCX) process between the solar wind ion (C^q+, N^q+, O^q+ etc.) and the interplanetary neutral matter. It is difficult to identify spectral features of SWCX with the spectral resolution of existing X-ray astronomy satellites.We are developing a laboratory experimental system with transition edge sensor (TES) X-ray microcalorimeters, in order to clarify the SWCX mechanism. This experiment is designed to measure Charge eXchange (CX) X-rays using Electron Cyclotron Resonance Ion Source (ECRIS) that generates multi-charged ions. Emission lines (OVIII: 2p→1s; 654 eV) by CX between O⁸⁺ and neutral He atom is aimed to be measured with energy resolution better than 10 eV. The TES microcalorimeter is cooled by a double-stage adiabatic demagnetization refrigerator (DADR), however, our TES microcalorimeter are not working potentially due to magnetic field contamination. This paper reports our experimental system, present results, and future prospects.