| 摘要 |
PURPOSE:To obtain laser beam uniform in intensity distribution without attenuating and blocking the laser beam, by allowing a plurality of laser beams each having an long oval cross-sectional shape to coincide in their long axes with each other and overlapping both beams so as to provide an interval before irradiation. CONSTITUTION:The laser beams 2, 2' emitted from two laser tubes 1, 1' arranged in parallel are magnified into a long oval sheet shape by objective lenses 3, 3' and a cylindrical lens 4 and the long axes of the long ovals of both magnified beams are allowed to coincide with each other on a focal surface and both beams are overlapped so as to provide an interval to be allowed to irradiate to obtain laser beam 6. The region 8 to be measured under a particle generating source 7 is irradiated with the laser beam 6 and the scattering beam 10 formed when fine particles 9 pass through the region 8 to be measured is condensed by a condensing lens 11 and processed by a signal processor 13 to detect and count the fine particles. By this method, the wide region 8 to be measured can be uniformly irradiated with the laser beam 6. |
