| 摘要 |
<p>Disclosed are methods and apparatus for detecting a wide dynamic range of intensity values from a beam from a sample, which is analyzed to determine the presence of defects on the sample. In one embodiment, the system directs an incident beam towards a sample and a detector positioned to detect a beam from the sample. The detector has a sensor (10) for detecting the incident beam and generating a signal and a non-linear component (182) coupled to the sensor arranged to generate a non-linear detected signal. An alternative embodiment provides a high-gain sensor (1502a) to detect the beam from the sample and a low-gain sensor (1502b) which also detects the beam and is used to sense the sample when the beam is originating in a bright region and protect the high-gain sensor by switching it off when the beam is too bright.</p> |
