特集 「特集」電気学会、応用物理学会共催の企画シンポジウム～放射線計測における高密度実装フロントエンド回路の先端技術～
高分解能CdTeイメージング検出器の開発と応用展開
2017 年 43 巻 3 号 p. 103-106
詳細
2017 年 43 巻 3 号 p. 103-106
High-quality CdTe semiconductor detectors with both fine position resolution and high energy resolution hold great promise to improve measurement in various hard X-ray and gamma-ray imaging experiments. ISAS/JAXA has been developing CdTe imaging detectors to meet scientific demands in space missions for over 15 years. Schottky CdTe diodes with In/CdTe/Pt or Al/CdTe/Pt contact are highlights of the instrumentation. We can extremely reduce a leakage current of devises, meaning it allows us to supply sufficiently high bias voltage to achieve high energy resolution. A 32mm-wide and 0.75mm-thick CdTe double-sided strip detector with a strip pitch of 250 μm has been established and was mounted on a focal point of a hard X-ray mirror in the latest Japanese X-ray satellite. The energy resolution measured in the test on ground was 1.7 keV (FWHM) at 59.5 keV. The detector with much finer resolution of 60 μm has been used in the FOXSI rocket mission to observe hard X-rays from the sun. Application to gamma-ray imaging above 300 keV is another topic of this article. We originally proposed a Si/CdTe semiconductor Compton camera which has a configuration of stacked Si and CdTe imaging detectors. Demonstrations in Fukushima and in-vivo molecular imaging are presented.
