| 摘要 |
<p>A particle sensor (10) has a mirror cavity (79) unobstructed by masks and the like. A light detector (75) is at the mirror secondary focal point (16) and well outside the mirror cavity (79). A variation includes a beam splitter (105) and a secondary light detector (77) to improve detection of larger particles (29). A second embodiment includes a pair of elliptical mirrors (11a, 11b) offset along the light beam (31). Light reflected by the second mirror (11b) represents only changes in laser power and light scattered by gas molecules (161). The resulting signal is subtracted from that produced by the first mirror (11a) to obtain a relatively 'clean' signal useful to assay very small particles (29). Another variation involves an imaging system (209) for collecting light scattered by gas molecules (161).</p> |
