Development of semiconductor imaging detectors for a Si/CdTe Compton camera

Watanabe, Shin; Takeda, Shin’ichiro; Ishikawa, Shin-­nosuke; Odaka, Hirokazu; Ushio, Masayoshi; Tanaka, Takaaki; Nakazawa, K.; Takahashi, Tadayuki; Tajima, H.; Fukazawa, Yasushi; Kuroda, Yoshihiro; Onishi, M.

doi:10.1016/j.nima.2007.05.306

Cited by 19 publications

(8 citation statements)

References 17 publications

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“…Due to the focusing optics, the sensitivity of the hard x-ray imaging system for the point source is 100 times better than those of nonfocusing instruments in the hard x-ray bands, such as hard x-ray detector onboard Suzaku (Suzaku/HXD). 4 The HXI is composed of a stacked semiconductor imager [5][6][7][8] and active shields surrounding the imager. The imager consists of five layers of double-sided strip detectors (DSD) with a strip pitch of 250 μm and detector area of 32 × 32 mm 2 .…”

Section: Introductionmentioning

confidence: 99%

In-orbit performance and calibration of the Hard X-ray Imager onboard Hitomi (ASTRO-H)

2018

J. Astron. Telesc. Instrum. Syst.

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The Hard X-ray Imager (HXI) onboard Hitomi (ASTRO-H) is an imaging spectrometer covering hard xray energies of 5 to 80 keV. Combined with the Hard X-ray Telescope, it enables imaging spectroscopy with an angular resolution of 1 0 .7 half-power diameter, in a field of view of 9 0 × 9 0 . The main imager is composed of four layers of Si detectors and one layer of CdTe detector, stacked to cover a wide energy band up to 80 keV, surrounded by an active shield made of Bi 4 Ge 3 O 12 scintillator to reduce the background. The HXI started observations 12 days before the Hitomi loss and successfully obtained data from G21.5-0.9, Crab, and blank sky. Utilizing these data, we calibrate the detector response and study properties of in-orbit background. The observed Crab spectra agree well with a powerlaw model convolved with the detector response, within 5% accuracy. We find that albedo electrons in specified orbit strongly affect the background of the Si top layer and establish a screening method to reduce it. The background level over the full field of view after all the processing and screening is as low as the preflight requirement of 1 − 3 × 10 −4 counts s −1 cm −2 keV −1 . © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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Section: Introductionmentioning

confidence: 99%

In-orbit performance and calibration of the Hard X-ray Imager onboard Hitomi (ASTRO-H)

2018

J. Astron. Telesc. Instrum. Syst.

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“…Aluminum, which has a small work function, makes a Schottky barrier on the interface with a p-type CdTe crystal. [8][9][10][11][12][13][14][15][16][17] Reduction of the leakage current through use of the Schottky barrier enables high energy resolution. Figure 3 shows a schematic view of the electrode configuration and a photograph of an engineering model of the CdTe-DSD.…”

Section: Imaging and Spectral Performance Of The Hxi Cdte-dsdmentioning

confidence: 99%

Imaging and spectral performance of CdTe double-sided strip detectors for the hard x-ray imager onboard ASTRO-H

et al. 2012

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The imaging and spectral performance of CdTe double-sided strip detectors (CdTe-DSDs) was evaluated for the ASTRO-H mission. The charcterized CdTe-DSDs have a strip pitch of 0.25 mm, an imaging area of 3.2 cm×3.2 cm and a thickness of 0.75 mm. The detector was successfully operated at a temperature of −20 • C and with an applied bias voltage of 250 V. By using two-strip events as well as one-strip events for the event reconstruction, a good energy resolution of 2.0 keV at 59.5 keV and a sub-strip spatial resolution was achieved. The hard X-ray and gamma-ray response of CdTe-DSDs is complex due to the properties of CdTe and the small pixel effect. Therefore, one of the issues to investigate is the response of the CdTe-DSD. In order to investigate the spatial dependence of the detector response, we performed fine beam scan experiments at SPring-8, a synchrotron radiation facility. From these experiments, the depth structure of the electric field was determined as well as properties of carriers in the detector and successfully reproduced the experimental data with simulated spectra.The main detector of the HXI is composed of four layers of double-sided silicon strip detectors (DSSDs) and one layer of cadmium-telluride double-sided strip detector (CdTe-DSD) as shown in the right panel of Figure 1. This hybrid structure is a result of optimization for better sensitivity throughout the observation energy range.

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“…DSSDs have been widely developed for astrophysical and nuclear physics applications [9] [10]. A DSSD with a strip pitch of 250 µm or 400 µm has been developed by our group as a scattering detector of a Si/CdTe Compton camera [10], [11], [12]. In this development, we added aluminum electrodes DCcoupled to p-stops in order to minimize the p-stop resistance since it generates Johnson noise.…”

Section: A Double-sided Silicon Strip Detectormentioning

confidence: 99%

Fine-Pitch Semiconductor Detector for the FOXSI Mission

Ishikawa

Tajima

Tanaka

et al. 2011

IEEE Trans. Nucl. Sci.

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The Focusing Optics X-ray Solar Imager (FOXSI) is a NASA sounding rocket mission which will study particle acceleration and coronal heating on the Sun through high sensitivity observations in the hard X-ray energy band (5-15 keV). Combining high-resolution focusing X-ray optics and fine-pitch imaging sensors, FOXSI will achieve superior sensitivity; two orders of magnitude better than that of the RHESSI satellite. As the focal plane detector, a Double-sided Si Strip Detector (DSSD) with a front-end ASIC (Application Specific Integrated Circuit) will fulfill the scientific requirements of spatial and energy resolution, low energy threshold and time resolution. We have designed and fabricated a DSSD with a thickness of 500 m and a dimension of 9.6 mm 9.6 mm, containing 128 strips with a pitch of 75 m, which corresponds to 8 arcsec at the focal length of 2 m. We also developed a low-noise ASIC specified to FOXSI. The detector was successfully operated in the laboratory at a temperature of 20 C and with an applied bias voltage of 300 V. Extremely good energy resolutions of 430 eV for the p-side and 1.6 keV for the n-side at a 14 keV line were achieved for the detector. We also demonstrated fine-pitch imaging successfully by obtaining a shadow image. Hence the implementation of scientific requirements was confirmed.

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Development of semiconductor imaging detectors for a Si/CdTe Compton camera

Cited by 19 publications

References 17 publications

In-orbit performance and calibration of the Hard X-ray Imager onboard Hitomi (ASTRO-H)

In-orbit performance and calibration of the Hard X-ray Imager onboard Hitomi (ASTRO-H)

Imaging and spectral performance of CdTe double-sided strip detectors for the hard x-ray imager onboard ASTRO-H

Fine-Pitch Semiconductor Detector for the FOXSI Mission

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