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Photometer Heads
The quality of LMT photometer heads represents the highest level of technology worldwide
Light-sensitive detectors
  • Si-photoelements of excellent quality and longtime stability
  • classified and selected for specific applications
  • illuminance and photocurrent absolutely proportional
Relative spectral responsivity
  • adapted to the spectral luminous efficiency V(λ) of the human eye (according to CIE, DIN)
  • very fine V(λ)-approximation by partial filtering, error f'1 (CIE) resp. f'1 (DIN) ≤ 1.0 %
  • fine V(λ)-approximation by full filtering, error f'1 (CIE) resp. f'1 (DIN) ≤ 2.5 %
  • UV and IR response < 0.1 %
Directional response
  • photometer heads for perpendicular light incidence
  • cosine correction for measurement of illuminance by light incidence from different directions, error f2 (CIE, DIN) £ 1.5 %
  • adapters and photometer heads for measurement of cylindrical (Ez) or semi-cylindrical (Esc) illuminance
Temperature dependence
  • without thermostatic stabilization α0 < 0.1 %/K
  • with thermostatic stabilization α0 < 0.01 %/K
  • measurement down to 0.00001 lx in combination with high precise LMT photocurrent amplifiers
Light sensitive surface
  • light sensitive surfaces 5, 10, 15, 30 mm Ø, and user specified diameters
Special detectors
  • photometer heads in splash-proof housing and defroster for outdoor installation
  • V'(λ) detectors for scotopic vision
  • Esy (photosynthesis) detectors
  • Ebi (bilirubin dissociation) detectors
  • blue/red detectors
  • photometer heads with photomultipliers
Technical data and calibration
  • individual test report for relative spectral responsivity
  • individual test report for directional response
  • specified errors acc. to DIN 5032 part 6 and 7 and CIE Publ. No. 69 (1987)
  • LMT calibration certificate for illuminance respositivity, traceable to PTB calibrated standard, relative expanded measurement uncertainty incl. the uncertainty of the Standard employed 0.8%
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