Development of Solar Flare X-ray Polarimeter with Micro-Pixel CMOS Sensors

Fuente: arXiv
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Autori principali: Hagino, Kouichi, Kato, Tatsuaki, Iwata, Toshiya, Ichihashi, Masahiro, Matsuhashi, Hiroumi, Fujimoto, Gen, Sato, Riki, Odaka, Hirokazu, Narukage, Noriyuki, Arai, Shota, Minami, Takahiro, Takashima, Satoshi, Bamba, Aya
Natura: Preprint
Pubblicazione: 2025
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author Hagino, Kouichi
Kato, Tatsuaki
Iwata, Toshiya
Ichihashi, Masahiro
Matsuhashi, Hiroumi
Fujimoto, Gen
Sato, Riki
Odaka, Hirokazu
Narukage, Noriyuki
Arai, Shota
Minami, Takahiro
Takashima, Satoshi
Bamba, Aya
author_facet Hagino, Kouichi
Kato, Tatsuaki
Iwata, Toshiya
Ichihashi, Masahiro
Matsuhashi, Hiroumi
Fujimoto, Gen
Sato, Riki
Odaka, Hirokazu
Narukage, Noriyuki
Arai, Shota
Minami, Takahiro
Takashima, Satoshi
Bamba, Aya
contents We are developing an X-ray polarimeter using micro-pixel CMOS sensors for solar flare X-ray polarimetry. The system consists of a 2.5-$μ$m pixel CMOS image sensor with a 12.8$\times$12.8 mm$^2$ imaging area and a readout system based on a Zynq System-on-Chip. While previous studies have validated this concept, no realistic feasibility studies have been conducted for the solar flare X-ray polarization observation. In this work, we performed polarization sensitivity measurements at synchrotron facilities. The results show that our polarimeter is sensitive to the X-ray polarization, exhibiting a modulation factor of 5-15% at an energy range of 6-22 keV. The measurements also determined the thickness of the sensitive layer to be approximately 5 $μ$m, and the thicknesses of the insensitive layers to be 0.8 $μ$m (Si), 2.1 $μ$m (SiO2), and 0.24 $μ$m (Cu). These measured thicknesses lead to a quantum efficiency of 3-4% at 10 keV. Based on these experimental evaluations, we estimated the sensitivity of the micro-pixel CMOS polarimeter system. We found that, when combined with a telescope with an effective area of $\sim$10 cm$^2$, this system can detect X-ray polarization with a polarization degree of a few percent for M-class flares.
format Preprint
id arxiv_https___arxiv_org_abs_2509_03914
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Development of Solar Flare X-ray Polarimeter with Micro-Pixel CMOS Sensors
Hagino, Kouichi
Kato, Tatsuaki
Iwata, Toshiya
Ichihashi, Masahiro
Matsuhashi, Hiroumi
Fujimoto, Gen
Sato, Riki
Odaka, Hirokazu
Narukage, Noriyuki
Arai, Shota
Minami, Takahiro
Takashima, Satoshi
Bamba, Aya
Instrumentation and Methods for Astrophysics
We are developing an X-ray polarimeter using micro-pixel CMOS sensors for solar flare X-ray polarimetry. The system consists of a 2.5-$μ$m pixel CMOS image sensor with a 12.8$\times$12.8 mm$^2$ imaging area and a readout system based on a Zynq System-on-Chip. While previous studies have validated this concept, no realistic feasibility studies have been conducted for the solar flare X-ray polarization observation. In this work, we performed polarization sensitivity measurements at synchrotron facilities. The results show that our polarimeter is sensitive to the X-ray polarization, exhibiting a modulation factor of 5-15% at an energy range of 6-22 keV. The measurements also determined the thickness of the sensitive layer to be approximately 5 $μ$m, and the thicknesses of the insensitive layers to be 0.8 $μ$m (Si), 2.1 $μ$m (SiO2), and 0.24 $μ$m (Cu). These measured thicknesses lead to a quantum efficiency of 3-4% at 10 keV. Based on these experimental evaluations, we estimated the sensitivity of the micro-pixel CMOS polarimeter system. We found that, when combined with a telescope with an effective area of $\sim$10 cm$^2$, this system can detect X-ray polarization with a polarization degree of a few percent for M-class flares.
title Development of Solar Flare X-ray Polarimeter with Micro-Pixel CMOS Sensors
topic Instrumentation and Methods for Astrophysics
url https://arxiv.org/abs/2509.03914