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Quantity |
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The basis unit Candela
of photometric quantity - luminous intensity - is defined
as follows: the Candela is the luminous intensity, in a
given direction, of a source that emits monochromatic
radiation of frequency 540x1012 Hz and that
has a radiation intensity in that direction of 683-1
watt per sterradian.
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Unit - Candela (cd), lumen (lm), lux (lx), cd·m-2, kelvin (K).
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Tasks
of the laboratory |
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The main tasks of the
Laboratory are research and development for the
realisation and dissemination of the units of the
physical quantities of luminous intensity, luminous flux,
illuminance, luminance, spectral temperature distribution
and calibration and certification of luminous intensity
standards and instruments.
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International
comparisons |
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CCPR Key Comparison K3-a
of Luminous intensity with Lamps as Transfer standards,
1998.
CCPR Key Comparison K4 of Luminous flux with Lamps as
Transfer standards, 1998.
CCPR Key Comparison K3-b of Luminous responsivity
measurement, 1998.
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Available
metrological services |
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| Quantity |
Range
of measurement |
Standard
uncetrainty |
| luminous
intensity |
(8 -
3000) cd |
3.0 % |
| luminous
flux |
(80 -
15000) lm |
3.0 % |
| spectral
distribution temperature |
(2000 -
2900) K |
2.0 % |
| illumination |
(2 -
10000) lx |
4.0 % |
| luminance |
(10 -
2500) cd/m2 |
5.0 % |
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Methods
of measurement: |
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- the
transfer of the luminous intensity scale is realised
using a method of variable distance on the optical bench
at the spectral distribution temperatures of 2024 K, 2353
K and 2856 K. The spectral distribution temperature is
measured by two colour filtres method. Standards of the
luminous flux are regularly verified at the BIPM Paris.
Calibration of the luminance meters is performed using
the source of luminance compared to the standards of
luminous intensity. Illuminance meters are calibrated by
the working luminous intensity standards - standard
photometric incandescent lamps. |
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Instruments
in use |
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The primary
standard of lumious intensity is based on properties of
special photometric heads with perfect match V ( ) function are
used. For transfer of luminous intensity scale a set of
unique photometric incandescent lamps and spectral
sensitivity photodetectors exactly corrected to the V () function are
used. Luninous flux measurement is performed using an
integrating sphere. The equipment is installed in a black
air-conditioned laboratory with the floor vibration
isolation. |
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Supplementary
activities |
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There is a
possibility to perform if negotiating with a consumer,
other measurements in the laboratory: measurement of
spectral intensity of the radiation sources in visible
and near IR region; spectral sensitivity calibration of
optical radiation detectors in spectral range from 350 nm
to 800 nm; CCPR Key Comparison of Luminous Responsitivity
K3b, 1998; CCPR Key Comparison of Luminous Intensity K3a,
1999; CCPR Key Comparison of Luminous Flux K4, 1999; CCPR
Key Comparison of Spectral Responsitivity K7, 2001. |
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