학술논문
Measurement of Charge Cloud Size in X-ray SOI Pixel Sensors
Document Type
Working Paper
Author
Hagino, Kouichi; Oono, Kenji; Negishi, Kousuke; Yarita, Keigo; Kohmura, Takayoshi; Tsuru, Takeshi G.; Tanaka, Takaaki; Uchida, Hiroyuki; Harada, Sodai; Okuno, Tomoyuki; Kayama, Kazuho; Amano, Yuki; Matsumura, Hideaki; Mori, Koji; Takeda, Ayaki; Nishioka, Yusuke; Fukuda, Kohei; Hida, Takahiro; Yukumoto, Masataka; Arai, Yasuo; Kurachi, Ikuo; Miyoshi, Toshinobu; Kishimoto, Shunji
Source
Subject
Language
Abstract
We report on a measurement of the size of charge clouds produced by X-ray photons in X-ray SOI (Silicon-On-Insulator) pixel sensor named XRPIX. We carry out a beam scanning experiment of XRPIX using a monochromatic X-ray beam at 5.0 keV collimated to $\sim 10$ $\mu$m with a 4-$\mu$m$\phi$ pinhole, and obtain the spatial distribution of single-pixel events at a sub-pixel scale. The standard deviation of charge clouds of 5.0 keV X-ray is estimated to be $\sigma_{\rm cloud} = 4.30 \pm 0.07$ $\mu$m. Compared to the detector response simulation, the estimated charge cloud size is well explained by a combination of photoelectron range, thermal diffusion, and Coulomb repulsion. Moreover, by analyzing the fraction of multi-pixel events in various energies, we find that the energy dependence of the charge cloud size is also consistent with the simulation.
Comment: 9 pages, 12 figures, accepted for publication in IEEE Transactions on Nuclear Science
Comment: 9 pages, 12 figures, accepted for publication in IEEE Transactions on Nuclear Science