Patent ID: 6934021
Filing Date: 2005-08-23
Classification: G01J,G01N

Abstract:
1. A measurement device for exciting constituent particles of a material to be measured through the use of an electric arc and for detecting the intensity of optical radiation emitted by excited constituent particles at the moment of relaxation from an excited state, the measurement device comprising: an arc electrode that comprises a rod part of a certain thickness and has a pointed end having a certain grinding angle, holding means for holding the pointed end of the arc electrode at a certain distance from the material to be measured for the duration of a measurement, a voltage and current supply for generating and maintaining a voltage between the arc electrode and the material to be measured and for supplying current through the arc electrode for the duration of a measurement, and focusing and detection optics for collecting optical radiation from an electric arc between the arc electrode and the material to be measured and for detecting the intensity associated with a certain selected wavelength of the collected optical radiation; wherein: the thickness of the rod part in the arc electrode is between 2 and 10 mm, the grinding angle of the pointed end of the arc electrode is between 40 and 130 degrees, the holding means are arranged to keep the pointed end of the arc electrode at a distance between 0.5 and 3 mm from the material to be measured for the duration of a measurement, the voltage and current supply is arranged to supply an ignition spark voltage between 5 and 20 kV, an arc voltage between 20 and 160 V and an arc current between 1 and 10 A, and the focusing and detection optics are arranged to collect and detect optical radiation at least on a wavelength of 193 nm.