Round robin comparison study on the form measurement of optical freeform surfaces

A round robin comparison of freeform form measurements was carried out by the project partners and stakeholders of a European metrology research project. Altogether six measuring instruments were considered: five different (pointwise and areal) optical devices and one tactile device. Three optical freeform surfaces were used for the comparison measurements, where two specimens were measured by five instruments and one specimen by four instruments. In this paper, the evaluation methods and results of this round robin are presented for the three freeform surfaces made from a temperature-stable material, Super Invar ®. The freeforms had diameters of 40 mm, 50 mm and 100 mm and best-fit radii of 39.75 mm (convex), 40.9 mm (convex) and 423.5 mm (concave). For comparison, the bilateral pointwise differences between the available measurements were calculated. The root-mean-square values of these differences ranged from 15 nm to 110 nm (neglecting spherical contributions) and provided an insight into the status of typical freeform measurement capabilities for optical surfaces.

WMO Interlaboratory Comparison in Europe with Loops Linkage and Data Processing

This article describes the interlaboratory comparison (ILC) of meteorological and hydrological calibration laboratories in the field of temperature (−30° to 40°C), humidity (10%–95% RH at room temperature), and pressure (800–1100 hPa). The ILC was organized by the World Meteorological Organization (WMO) Regional Instrument Centre (RIC) at the Slovenian Environment Agency and University of Ljubljana, Faculty of Electrical Engineering, Laboratory of Metrology and Quality as an accredited interlaboratory comparison (proficiency testing) provider according to the ISO/IEC 17043:2010 standard. The ILC was organized in the target area of WMO Regional Association VI (Europe). The protocol and procedure for ILC were developed within European Metrology Research Project (EMRP) MetoMet2. The participants used their standardized procedures for calibration. Because of the large number of participating laboratories (18) from 17 countries, the ILC was organized in two loops, which were linked via four linking laboratories and evaluated using the En number. The equipment used in both loops exhibited stability and uncertainty, which enabled evaluation of the laboratories’ capabilities. The article presents the data processing, the linkage procedure, and the main results for all three categories (temperature, humidity, and pressure). It was observed that some of the laboratories had unusually low uncertainties. From the metrological point of view, the authors present some comments and suggestions to the laboratories, the results of which differ from the reference ones. The conclusions can help also other meteorological laboratories and organizations that did not participate in the ILC with their everyday work.

Recent progress in chemical measuring capabilities in INM as a result of EMRP/EMPIR Programme

New metrology capabilities in chemical area are of great interest as they underpin the traceability of measurement results reported in environment, health or food sectors. To develop such capabilities a consistent research work is needed. Since 2009, the European Metrology Research Program (EMRP) enabled the National Institute of Metrology (INM) from Romania to join several Joint Research Projects (JRPs) in chemical field. Main outcomes of this helped INM in developing and implementing measurement capabilities in gas chromatography (GC) and inductive couple plasma mass spectrometry (ICP-MS). Accordingly, a brief review of the best practice achieved at INM after participating in ENV08 and SIB09 is described. Further, the European Metrology Programme for Innovation and Research (EMPIR) facilitated expanding the existing metrology capabilities/infrastructure within the frame of two research potential projects (RPOT) in chemical field. Aspects regarding developing ICP-MS technique for measuring mass fractions of elements in natural matrix are presented in the frame of EMPIR RPOT1601. Also, some developments are presented in gas chromatography as a result of participating in the EMPIR RPOT1602.

Results of the round robin calibration of reference solar cells within the PhotoClass project

An intercomparison of terrestrial photovoltaic (PV) calibrations was performed among a number of European calibration and testing laboratories that participated in the European Metrology Research Program (EMRP) project “PhotoClass”. The purpose of this intercomparison was to evaluate the comparability of calibration and testing services within the stated uncertainties of the individual laboratories. The calibration objects were two world photovoltaic scale (WPVS)-type reference solar cells, one made from crystalline silicon and one made from GaAs. The calibration value (CV) was the short-circuit current under standard test conditions (ISTC). In conclusion, it was found that the CVs are all consistent within the stated uncertainties. This result strengthens the reliance in the calibration chain and in the PV calibration infrastructure in Europe.