Systems and methods for inspecting a wafer with increased sensitivity are provided. One system includes an inspection subsystem configured to direct light to a spot on the wafer and to generate output signals responsive to light scattered from the spot on the wafer. The system also includes a gas flow subsystem configured to replace a gas located proximate to the spot on the wafer with a medium that scatters less of the light than the gas thereby increasing the sensitivity of the system. In addition, the system includes a processor configured to detect defects on the wafer using the output signals.

An apparatus for examining a specimen with a beam of charged particles, where charging of the specimen is avoided or reduced by injecting inert gas onto the sample's surface. In order to avoid interactions with the electron optics, various embodiments are disclosed for providing a rotationally symmetrical nozzles and/or electrodes. Additionally, embodiments are disclosed wherein a plurality of gas conduits are arranged in a rotationally symmetrical manner. Alternatively, the conduit is incorporated into an element of the electron optics, such as the magnetic lens. Also, in order to reduce or eliminate interaction of the electrons with the gas molecules, embodiments are disclosed wherein the gas is pulsated, rather than continually injected.

A contaminant reduction system comprises an assembly of appropriate size and shape for mounting within a sealed or semi-sealed hard disk drive (HDD). The system comprises a photocatalytic surface mounted in close proximity or in contact with a light source which may be utilized as a means for activation. The photocatalytic surface is preferably titanium dioxide (TiO.sub.2); it may be other metal oxide catalyss that can be photochemically activated such as zinc oxide (ZnO). The activation is achieved utilizing a lamp which illuminates the photocatalyst and has an output below 100 nm.

A foreign-matter detector for detecting foreign matter contained in an article P transported between a transmitter (17) and a receiver (18). The detector (1) includes a signal extractor (2) for extracting a signal (e) having a predetermined phase difference relative to a transmitted signal (a) from the transmitter (17), based on a phase of the transmitted signal (a) from the transmitter (17) and the received signal (b) from the receiver (18), a specific value setting unit (25) for setting, through an external input operation, a specific value for the level of the extracted signal (e) which is outputted from the signal extractor (2) and which is attributable to the article (P) free from foreign matter to be detected, and a level adjusting circuit (24) for adjusting the signal extractor (2) or the receiver (18) to cause the level of the extracted signal (e) attributable to the article itself to assume the specific value inputted. A foreign-matter detecting system is also provided which makes use of the foreign-matter detector.