LENGTH LABORATORY
       
      Quantity - length.
      Unit - nm, mm.
      Tasks of the laboratory
      The main task of the Laboratory is the realisation and maintainance of the length unit and its transfer to the working standards.
      International comparisons
      CCL-K10 world-wide key comparison of HeNell2 lasers 633 nm.
EUROMET.L-K1 - Gauge blocks.
  Available metrological services
     
Calibration or Measurement services Measurand Level or Range Expanded incertainty (k=2)
Stabilizes HeNe lasers 633 nm 633 nm (474 THz) 2 x 10-9
Gauge blocks (0.1 - 100) mm (0.02 + 0.2 L) µm; L in m
(0.5 - 100) mm (0.05 + 0.5 L) µm; L in m
Long gauge blocks (100 - 1000) mm (0.02 + 0.2 L) µm; L in m
(125 - 1000) mm (0.05 + 0.5 L) µm; L in m
Line Scales (0.01 - 10) mm from 0.04 µm to 0.1 µm
(10 - 200) mm from 0.04 µm to 0.2 µm
Line Standards (1 - 1000) mm (0.1 + 0.2 L) µm; L in m
Standards of 2-D microstructures (1 - 300) µm 0.05 µm
Special length standards (0 - 3000) ~ 1 µm
    Methods of measurement:
      The vacuum wavelength of working HeNe lasers is determined using a beat frequency method. The beat frequency is equal to the frequency between the frequency of the national Standard of Length and the frequency of the laser to be calibrated.
      With regard to the reference standard a division of measuring methods into two groups is possible:
      - the reference standard is the wavelength of the stabilized working HeNe laser. This method is being used on 1 m intereferometer, LID, Line Interference Comparator, combination Of ULM3m ZEISS with laser interferometer. The exception are two INKO ZEISS comparators, which use interference method (kr lamp as the light source), but the traceability is indirect via 100 mm gauge block calibrated at 1 m interferometer;
- the reference standards are marerial measures (gauge blocks or line standards), calibrated using the interference method.This method is being used at ULM3m ZEISS (long gauge blocks and possible line standards) are vertical length measuring machine TESA (gauge blocks).
       
  Instuments in use
      The National Standard of Length is represented by two iodine stabilized HeNe lasers, developed at the SMU and devices for the transfer og length unit. The frequency of these lasers was internationally compared in 1988 and 1994 to the BIPM laser frequency, as well to the lasers of nine foreign metrological institutes, with an expanded uncertaiunty of 5 x 10-11. All transfer devices, serving for the calibration of material measures, are directly traced to the National Standard of Length.
1 m Interferometer is the laser interferometer of Michelson's type. It is used for the calibration of gauge blocks from 100 mm up to 1000 mm of length.
The set of INKO ZEISS interference comparators serves for the calibration of gauge blocks up to 100 mm of length by means of chosen wavelengths of the Krypton lamp. The traceability to the National Standard of Length is realised through the calibration of 100 mm gauge blocks calibrated interferentially.
     
The vertical length measuring machine TESA, Abbe's length measuring device with the laser interometer LMS-100 (LID), the MPVCD-Leitz Microscope serves for the calibration of special length standards used in electronics and ranging from 1 µm to 300 µm, the Line Interferometric Comparator has been developed and made in the SMU containing the laser interferometer LOS with the HeNe laser 633 nm as the light source, the Length measuring device ULM3m ZEISS combined with TESA MODUL serves for the calibration of line scales from 100 mm up to 1000 mm using the comparison method.
      All standard devices are installed in air-conditioned laboratories at (20 ± 0.1)°C. Laboratories are equiped with a floor vibration isolation.
       
     
Contact
Mgr. Anna Fodreková Dr. Roman Fíra Mrs. Eva Haršonová
phone: + 421 2 60294 222 phone: + 421 2 60294 284 phone: + 421 2 60294 222
fodrekova@smu.gov.sk fira@smu.gov.sk harsonova@smu.gov.sk