We describe the status of the development of an interferometer for absolute distance measurements with an intrinsic compensation of the refractive index of air, intended as a primary standard for the calibration of geodetic baselines. Two frequency-doubled Nd:YAG lasers are offset locked with a frequency difference of ≈20 GHz at the infrared 1064 nm fundamental wavelength. The resulting synthetic wavelengths of 15 mm for the infrared and 7.5 mm for the frequency-doubled green light are used as the scale for the measurements. Longer synthetic wavelengths are generated by acousto-optic frequency shifters. Based on the dispersion in air between green and infrared light the refractive index can be compensated. The attempt is demanding since uncertainties of the interferometric measurements for the optical wavelengths are scaled by a factor of nearly 300 000 in the refractive index compensated result. First comparisons up to 50 m length between this interferometer and a HeNe reference are presented. The deviations are smaller than ± 200 µm and dominated by a non-linearity from problems in the collimation of the measurement beams. In the linear parts the deviations are below ± 100 µm.

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Abstract. Medical devices with measuring function are regularly used in healthcare systems all over the world with the aim of prevention, diagnosis, and treatment of diseases. Considering the importance of these devices in daily activities of medical professionals and impact of their measurements on the health of patients, safety and accuracy of their measurements is becoming the topic of interest. Numerous international guidelines define how healthcare institutions should perform these conformity assessment but in some countries, where those guidelines are not adopted, it is necessary to implement directives of new approach for various groups of medical devices. Directives of new approach in terms of medical devices and their conformity assessment can be implemented in the area of legal metrology, as it is done in Bosnia and Herzegovina. This paper presents achievements and activities of Institute of Metrology of Bosnia and Herzegovina (IMBIH), the competent state authority for metrology in Bosnia and Herzegovina, in the area of legal metrology for the particular group of medical devices with measuring function. These achievements and activities refer to the adoption of appropriate legislation for type approval, verification, and creating an adequate legal framework for controlling medical devices after they are sold on the market. In addition, considering complexity and variety of medical devices related to measuring characteristics, and also due to the problem of inadequate or not defined traceability routes, the medical devices will continue to be in focus of metrological practice and science. Establishing the comparative approach to the type approval for these devices in the area of the legal metrology is the final aim.

A EURAMET key comparison of the national pressure standards in the range 0.7 MPa to 7.0 MPa of gas gauge pressure was carried out. The circulation of the transfer standard began in November 2011 and lasted until November 2016. The measurand of the comparison was the effective area of the piston-cylinder assembly determined by gauge pressure measurements in the range from 0.7 MPa to 7.0 MPa. As the comparison reference value, the weighted mean of the results of the laboratories with primary pressure standards was used. With this reference value, all the participants who delivered the results demonstrated equivalence respective to the reference value within expanded uncertainties (k = 2) on all the range. The results of this comparison were linked to CCM key comparison CCM.P-K1.c. Also in relation to the reference values of CCM.P-K1.c, all participants demonstrated agreement within expanded uncertainties (k = 2) at all pressure points. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

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