Exemplary embodiments are directed to wireless power transfer. A first position identifier uses a first layer error conversion coefficient indicating an error of a decoding signal for an input signal so as to search for a band having a large error in a relatively wide bandwidth in all the bands of the input signal and generates first position information indicating the identified band. At least two of the sheave portions are spaced apart along a shaft and a portion of the guide rail extends toward the axis beyond a plane formed tangent to the outside diameter of the sheave portions. Each of the nuclear detector heads within the system includes a variable radiation shield disposed adjacent a radiation receiving face on the detector head. If the scan number is odd, an even scan number which is smaller by 1 than the odd scan number is obtained, and the obtained even scan number is set as a practical scan number. Further, the influent feed trough preferably includes a bottom that is disposed above the at least one layer of filter media.