“Development of the X-ray polarimeter using CMOS imager: polarization sensitivity of a 1.5 μm pixel CMOS sensor” was accepted for publication in NIM-A. Bamba Lab has been working on the project “cipher”, which aims to observe polarized X-rays with a tiny pixel CMOS sensor. In this paper, we evaluate the X-ray polarization measurement performance of a CMOS sensor with a pixel size of 1.5 μm and show that the polarization measurement performance improves with decreasing pixel size. For more information, please click here.