Abstract: A method for in situ sampling and monitoring of a fluid flowing in a flow path, whereby the fluid is to be directed to a chamber a first valve may provide a connection between an inlet to the chamber and the flow path and a second valve may provide a connection between flow path, comprising the following steps: a) opening the first valve and the second valve to let the incoming fluid flow through the inlet to the chamber outlet into the continuation of the fluid path, thereby allowing fluid to circulate through the chamber for a certain time, b) trapping the fluid in the chamber by closing the second valve and thereafter closing the first valve, c) opening a valve 9 pressure in the chamber suitable for monitoring the fluid, d) opening an access valve 11 and leading the fluid trapped in the chamber into a monitor system wherein the fluid is analyzed, and thereby providing the data representing the fluid characteristics, e) providing exit for the fluid analyzed through a further fluid path possibly to a low pre

Abstract: A scanning system for scanning in first and second dimensions a desired surface topology of a sample, the scanning device comprising: a light source for producing a collimated light beam; a first scanning device responsive to the collimated light beam from the light source for producing a first scanned beam in a first dimension with a constant optical path length; and a second scanning device coupled between the first scanning device and the sample for focusing and scanning the first scanned beam in a second dimension onto the surface region of the sample to cause the collimated light beam to scan the surface topology of the sample with a constant optical path length in each of the first and second dimensions of the desired topology of the sample. In a second embodiment of the invention, a beam of light is focused by a first lens before a scanner and the scanner is rotated.