JP2502050B

PURPOSE:To realize an accurate irradiation of electron beams, by analyzing through an irradiation of electron beams depending on the central position found by a computing measure from data in a memory. CONSTITUTION:CPU 26 finds the center of particles from signals stored in a memory 24 through the following formula. Electron beams 10 are irradiated at the particle position corrected by the computation, analyses are performed by specific X-rays, and, correction of the specific position and the step of analysis at the corrected position are repeated on all the specified particles until the analyses are completed. Therefore, since the variation of position is corrected during the irradiation of electron beams onto particles, a continuous analysis of microparticles can be carried out rather easily.