SPECTRAL TRANSMITTANCE LABORATORY 
       
  Quantity - Spectral Transmittance and Absorbance at a particular Wavelength.
  Unit - 1.
  Tasks of the laboratory
      The main task of the laboratory is the realisation of Spectral Transmittance and Absorbance scales.
  International comparisons
      International equivalence of the primary standard equipment was substantiated by bilateral comparison measurements with LNE (France), multirateral comparison measurements organised by SMU within project COOMET 138/SK/96 (GUM PL, UkrCSM UA, CESM BY, VNIIM RU). Multilateral key comparison measurements organised by BIPM within the project CCPR K-6 (NIST USA, NPL U.K., PTB Germany, HUT Finland, MSL New Zeland, etc.) is in evaluation stage.
    Available metrological services
      Certified reference materials (CMRs) for UV-VIS molecular absorption spectrometers calibration. Calibration of spectrometric cuvettes and of optical filtres for UV-VIS spectrometry.
 
Methods of measurement:
      - calibration of the CRMs performed on the spectral transmittance primary standard equipment
      - calibration of the spectrometric cuvettes realised on the primary standard equipment;
      - calibration of the optical filtres performed on the primary standard equipment;
      - traceability of the spectral trasmittance measuring instruments (UV-VIS molecular absorption spectrometers) used in practice, is assured by means of the CRM set.
 
Metrological charasteristics of the CRMs:

Type of CRM Spectral
Range (nm) 		SSW
(nm) 		Certified quantity Unit Measured Range U (k=2)
Ho2O3 (wavelength) 240 - 650 0.1 - 5.0 wavelength nm 240 - 650 0.031 - 0.051
K2Cr2O7 (absorbance) 235 - 350 1.0 - 2.0 absorbance 1 0.1 - 1.5 0.00016 - 0.0058
Co-Ni (absorbance) 302 - 678 1.0 - 2.0 absorbance 1 0.1 - 0.9 0.00036 - 0.0024
Kl (stray light) 260 0.2 specif. absorption coeff. dm3·g-1·cm-1 0.261 0.016

    Instruments in use
      The Spectral Transmittance primary standard equipment is based on commercially produced UV-VIS molecular absorption spectrometers Varian Cary 4E (USA), equipped by wavelength scale (175nm - 900 nm range) and changeable spectral slitwidth (in range from 0.1 nm to 5.0 nm). Standard fused quartz cuvette NIST SRM 932 with inner pathlength (1.00000 ± 0.00005) cm is integral part of primary standard equipment.
     

Quantity Unit Measured range SSW (nm) U (k=2)
Spectral Transmittance 1 0 -1.0 1.0 5.4·10-5*
Absorbance 1 0 - 1.5 1.0 2.4·10-4*
Wavelength nm 200 - 800 1.0 2.4·10-2*
* 5 year stability

       
     
Contact
Mrs. Marta Obenrauchová Dr. Viliam Pätoprstý
phone: + 421 2 60294 228 phone: + 421 2 60294 285
e-mail: obenrauchova@smu.gov.sk e-mail: patoprsty@smu.gov.sk