A Cross-Scanner of the type
			    K-50 is used for measurement of Possion's ratio
			    at a climatic chamber up to 250 °C. The scanning range at the sample
			    is 50 mm for longitudinal and lateral strain. The system is
			    integrated in the tensile tester and adjusted
			    for use at the climatic chamber.
			    The climatic chamber was modified by
			    Fiedler Optoelektronik GmbH. An evacuated tube (type "steel") is used to guide
			    the laser beams close to the specimen in order to minimize the effects of air
			    flow to the accuracy of the measurement.
			    The mounting of the laser
			    extensometer provides vertical adjustments and easy motion of the laser
			    extensometer into and out of the climatic chamber. Although the extensometer is
			    heavily integrated into the testing equipment, the K-50 as well as the chamber
			    can easily be moved away.
				
Deutsches Kunststoff-Institut, Abteilung Technologie, Darmstadt, Deutschland