Abstract: A pair of iron magnetic poles are disposed at the exit of electrons of each of deflecting magnets in an electron storage ring, in which electrons are stored during a certain period of time while being rotated therein, for generating a magnetic field in the direction opposite to that generated by the deflecting magnets. The magnetic field generated by these iron magnetic poles compensates deviations of the orbit of electrons due to the magnetic fringe field of each of the deflecting magnets.

Abstract: In an electron storage ring comprising: a bending magnet for bending an electron beam; a focusing magnet for focusing the electron beam; a radio-frequency accelerating cavity for accelerating electrons; and a vacuum chamber, a voltage component fluctuating with time, e.g., sinusoidally is superposed on the power source of the focusing magnet, in case the electron beam is to be accelerated, to fluctuate the intensity of the focusing magnet. As a result, the number of the betatron oscillation of electron can be changed each time the electrons pass through the focusing magnet so that the damping rate can become higher than the growth rate of the instability of the beam to suppress the instability of the electron beam.

Abstract: Method and apparatus for estimating the location of an unknown sound source in a structure to be monitored, wherein sounds from at least three known sound sources are detected by a plurality of detectors. At least one of peak value data and signal arrival time data derived from the outputs of the detectors are classified for each of the known sound sources and stored in a storage. Pattern differences from each of the known sound sources to a number of predetermined positions respectively, are calculated to prepare for each of the known sound sources a correspondence table indicating relationships between the calculated pattern difference and the real distances from the known sound source positions to the predetermined positions, the correspondence table being stored in a storage. The pattern differences for each of the known sound source positions are calculated on the basis of the sound signal data derived through detection of a sound from an unknown sound source and the data stored in the storage.