Report on RMO supplementary comparison COOMET.L-S9. COOMET 440/RU/08 International comparison of stabilized He-Ne/I2 lasers at wavelength 633 nm

The report summarizes a comparison of frequency stabilized He-Ne/I2 lasers, which may be used as frequency or length standards. The goal was to confirm the declared measuring capabilities of these frequencies and to determine degree of equivalence of the national length measurement standards of the participating countries. The measurements in the comparison include measurement of the lasers' frequency stability and frequency reproducibility. The comparison format was a circular comparison and the lasers of three national metrology institutes have been delivered to VNIIM during the period from June 2009 to September 2011. Measurements were made by beat-frequency comparison with laser VNIIM02 which had previously participated in comparison CCL-K11. Frequency differences between 0.6 kHz and 12.5 kHz were obtained, with Allan Deviations ranging from 1.05 ? 10-12 (?=160 s) to 5.72 ? 10-12 (?=10 s). 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 CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).