A three-dimensional measurement of cosmic muon with a spark chamber

 "Muon tomography" is an analysis method of object structure with cosmic muon transmission. It has been used to analyze the amount of reinforced concretes of buildings, or the structure of volcanos, pyramids, and blast furnaces in ironworks. Additionally, the method is applied to the reactor core of the Daiichi (first) Fukushima Nuclear Poer Plant. 

 

 We used a cube spark chamber to measure the zenith angle distribution of cosmic-ray flux. To reconstruct the three-dimensional tracks, photos of the spark chamber were taken from two different directions at the same time. A coincidence signal of the plastic scintillation counters was used as a trigger for a switch of high voltage power supply to the spark chamber and the cameras.

 We have the plan to observe the cosmic-ray some places: close to windows, upstairs, downstairs, and other locations. From those data, we would like to estimate the amount of substance of the building.