[U-02_28AM2] Particle Geophysics

★ [U02-06] Development of Nuclear Emulsion Detector for Cosmic-ray Muon Radiography and Its Applications

*Kunihiro MORISHIMA¹, Akira NISHIO¹, Yoshito KATO¹, Toshiyuki NAKANO¹, Mitsuhiro NAKAMURA¹ (1.Nagoya University)

Keywords:cosmic-ray muon radiography, nuclear emulsion, non-destructive observation, Fukushima Dai-ichi nuclear power plant

We are developing nuclear emulsion and its automatic analysis system for cosmic-ray muon radiography (muography). Nuclear emulsion is very high-sensitive photographic film for detecting 3-demensional trajectories of charged particles like muon in its volume with the very high position resolution (sub-micron), which gives us the very high angular resolution (a few mrad). In addition, nuclear emulsion does not require electronic power, the size is very compact and the weight is very light. And also, it is easy to perform the tomographic analysis using multiple detectors placed around the target. These features have advantages in the field observation for the measurement of geoscience object, archeological object, or in the disaster area like Fukushima Dai-ichi nuclear power plant.In the case of Fukushima Dai-ichi nuclear power plant, high radioactivity shielding and lack of electronic power supplies should be taken into account. Nuclear emulsion is the powerful candidate used in such area. We have conducted the basic study of muon radiography of reactor core at fast reactor Joyo, which belongs to Japan Atomic Energy Agency (JAEA), in order to demonstrate the imaging of the reactor core. The result validates the observation of the reactor core with high resolution.We will present technical developments of nuclear emulsion, latest scientific results including other observed objects and future prospects.