An international comparison of 127I2-stabilized 633 nm He-Ne lasers locked either by the fifth- or the third-harmonic technique was carried out at the Finnish Centre for Metrology and Accreditation (MIKES) in September 1998. The participating laboratories were the MIKES; the Metrology Research Institute, Helsinki University of Technology (HUT); the Chinese National Institute of Metrology (NIM); the Czech Metrological Institute (CMI); the D. I. Mendeleyev Institute for Metrology (VNIIM); and the Bureau International des Poids et Mesures (BIPM). Raw measured frequency differences between lasers were in the following ranges: −5.2 kHz to +11.9 kHz and −5.8 kHz to +4.9 kHz for the third- and fifth-harmonic locking techniques, respectively. The frequency offsets between the third- and fifth-harmonic techniques for different components (d to g) were in the range 26 kHz to 35 kHz. The relative frequency stability of lasers given by the Allan standard deviations reached 2.6 × 10−13 for two lasers using the third harmonic and only 1 × 10−12 for the same lasers using the fifth harmonic for a 2000 s sampling time. This comparison is part of the ongoing laser comparison carried out under the auspices of the Consultative Committee for Length (CCL, formerly CCDM) of the Comité International des Poids et Mesures (CIPM); it is also a EUROMET project (No. 462).
Increasingly more intense beams of radioactive isotopes allow moving into unknown areas of the nuclear chart and exploring the limits in nuclear binding and proton-to-neutron ratio. New aspects of nuclear structure and important results for nuclear astrophysics are obtained. The paper provides some overview of experimental developments, facilities and research results; and is intended to set the stage for the many exciting examples of research presented in these proceedings.
The results of the work to create a complex of high-precision hardware for the unit of length reproduction and transferring carried out at “D. I. Mendeleyev Institute for Metrology (VNIIM)” are represented. This complex will serve as the basis for the further development of the reference base of the Russian Federation in the field of length measurements and will allow reproduction of the unit of length at two wavelengths of 633 nm and 532 nm, as well as measurements of the wavelength of laser sources in vacuum in the range from 500 to 1050 nm.
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