MASS-SPECTROGRAPH FOR LASER IONIZED NEUTRAL PARTICLE

摘要

PURPOSE: To reduce the sensing limit concentration by using all produced photo- excited ions through utilization of all laser pulses. ;CONSTITUTION: In synchronization with light emission of ultraviolet pulse laser, voltage is swept on a scanning electrode in the X-axis and Y-axis direction. Thereby the time required for an ion beam to make one run of scanning over a region to be analyzed is made equal to the light emitting interval of the pulse laser, and it is so arranged that the ultraviolet pulse laser is cast onto neutral particles produced from the central part of the ion beam irradiation region. Concretely, if the repetitive frequency of ultraviolet pulse laser is represented by (f) and the number of scanning lines by (n), sawteeth voltages of f-Hz and nxf-Hz are swept on the scanning electrode in the X-and Y- direction. Thereby the ultraviolet pulse laser makes light emission only when the ion beam comes to a certain position in the region to be analyzed, and the phase of the laser light emission is adjusted so that light emission takes place (t) sec, after sputtering. Thereby only the neutral particles from the central part which is flat can be ionized and sensed as photo-excited ions, which allows enhancing the resolution in the depth direction and improving the sensitivity.;COPYRIGHT: (C)1994,JPO&Japio