1. Development of the X-ray polarimeter using CMOS imager: polarization sensitivity of a $1.5~{\rm \mu m}$ pixel CMOS sensor
- Author
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Iwata, Toshiya, Hagino, Kouichi, Odaka, Hirokazu, Tamba, Tsubasa, Ichihashi, Masahiro, Kato, Tatsuaki, Ishiwata, Kota, Kuramoto, Haruki, Matsuhashi, Hiroumi, Arai, Shota, Minami, Takahiro, Takashima, Satoshi, and Bamba, Aya
- Subjects
Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
We are developing an imaging polarimeter by combining a fine-pixel CMOS image sensor with a coded aperture mask as part of the cipher project, aiming to achieve X-ray polarimetry in the energy range of $10$$\unicode{x2013}$$30~\mathrm{keV}$. A successful proof-of-concept experiment was conducted using a fine-pixel CMOS sensor with a $2.5~\mathrm{\mu m}$ pixel size. In this study, we conducted beam experiments to assess the modulation factor (MF) of the CMOS sensor with a $1.5~\mathrm{\mu m}$ pixel size manufactured by Canon and to determine if there was any improvement in the MF. The measured MF was $8.32\% \pm 0.34\%$ at $10~\mathrm{keV}$ and $16.10\% \pm 0.68\%$ at $22~\mathrm{keV}$, exceeding those of the $2.5~\mathrm{\mu m}$ sensor in the $6$$\unicode{x2013}$$22~\mathrm{keV}$ range. We also evaluated the quantum efficiency of the sensor, inferring a detection layer thickness of $2.67 \pm 0.48~{\rm \mu m}$. To develop a more sensitive polarimeter, a sensor with a thicker detection layer, smaller pixel size, and reduced thermal diffusion effect is desirable., Comment: 18 pages, 8 figures, 5 tables, accepted for publication in NIM-A
- Published
- 2024