PR450 Phototherapy Radiometer
Irradian Limited
9
Irradian holds a number of tungsten halogen and deuterium lamps and
silicon photodiode standards which are routinely calibrated by the
National Physics Laboratory in the UK.
Four methods for calibrating the radiometer are available:
i) Radiometric calibration with monochromatic light at 450nm in units of
W/m
2
.
ii) Radiometric calibration with monochromatic light at 450nm, the
sensitivity is then divided by the bandwidth at FWHM to give a
calibration in units of W/m
2
/nm.
iii) Spectroradiometric calibration. Light source is scanned with a
spectroradiometer between 425 and 475nm. The total integrated
irradiance is then recorded and divided by the spectral range to give
calibration in units of µW/cm²/nm with the PR450 radiometer
calibration adjusted to match the spectroradiometer.
iv) Each spectroradiometric value in (iii) can be adjusted with the
action spectrum to form a weighted irradiance with the PR450 set to
match this.
Note the spectroradiometric calibrations are dependent on the light
source. It may be necessary to use correction values if accurate
measurements are required for both fluorescent and discharge type
lamps.
As with all measuring equipment a routine calibration is recommended,
typically annually, but with frequent use by a number of different users a
shorter recalibration period may be necessary.
