Spanish facilities and fisrst results in measuring thermodynamic temperature using the radiance method

Newport Pagnell, Buckinghamshire, May 18-19 2015; https://royalsociety.org/science-events-and-lectures/2015/05/new-kelvin/Currently, the dissemination of the kelvin, according to the International Temperature Scale (ITS-90), at high temperatures is realised at the Centro Español de Metrología (CEM) by using the fixed points of Ag and Cu and a standard radiation thermometer. Recently, absolute radiometry has been proposed by the CCT Working Group 5 [1] to be included in future revisions of the Mise-en-Practique for the kelvin (MeP-K). The Centro Español de Metrologia (CEM) in collaboration with the Instituto de Óptica of the Consejo Superior de Investigaciones Científicas (IO-CSIC) has been working in the following lines linked to this new alternative to disseminate the kelvin: ¿ Absolute calibration, i.e., calibration in terms of the thermodynamic temperature, of commercial radiation thermometers, by using a facility based on a monochromator and a high stability lamp [2]. At present, the uncertainties of these measurements, obtained with a KE-LP2 radiation thermometer, are about the ones obtained with the ITS-90 method, i. e. from 0,3 K to 1,1 K (from 1084,62 °C to 2474 °C, k = 2). Some improvements in the facilities described in [2] have been implemented in order to reduce uncertainty. ¿ Development of a filter radiometer to measure the thermodynamic temperature. It has been designed by CEM based in NPL previous work [3]. This filter radiometer can be calibrated with a laser based experimental setup, which improves the above measurement uncertainty [4]: from 0,2 K to 0,7 K (from 1084,62 °C to 2474 °C, k = 2). Because of some problems with the radiometer stability at 2500 °C, some changes in the design have been done. The facilities used in [2] and [4] are currently been developed at CEM site as the transportation of the instruments for calibration has caused significant drifts. A complete description of IO-CSIC and new CEM facilities will be presented, together with the results obtained on the determination of the WP1 InK cells thermodynamic temperatures by using both, a radiation thermometer with an absolute calibration, and a filter radiometer.Peer Reviewe