2018 年 71 巻 p. 161-168
Muography is an emerging visualization technique for inspection of large-sized objects with the measurement of the absorption rate of cosmic-ray muons. Present paper introduces the first prototype of a Multi-Wire-Proportional-Camber (MWPC)-based borehole detector. The designed tracking system is based on the so-called Close Cathode Chamber (CCC) concept, which provides easily handling and robust detectors. The 18-cm-length detector is covering a sensitive area of 20 cm × 32 cm and an angular acceptance up to 60 deg with close to full tracking efficiency (99 %), reasonable position resolution of 1.8 mm and angular resolution of 10 mrad. The detector has been tested inside a shallow shaft and an underground iron pillar with concrete basement has successfully been imaged with the resolution of 15 cm within 15 days, which indicates the future industrial usage of MWPC detectors and encourages the application oriented development of this technology for borehole-based muography.