Selecting the proper physical actinometer
, such as a radiometer, to measure light is not trivial either.
Hubig, "Azobenzene as a convenient actinometer
: evaluation values for UV mercury lines and for the N2 laser line," Journal of Photochemistry, vol.
For example, the Kipp & Zonen Linke-Feussner actinometer
has an aperture of 10.2[degrees] (Gueymard, 1998; Garg and Prakash, 2006).
Benzophenone was used as an actinometer
for measuring the photon concentration.
Table 1 compares average CAD-predicted fluence rates in the experimental chamber with measurement-based estimates of fluence rate using three sensing devices: (1) a fiat sensor, (2) a cylindrical sensor, and (3) a chemical actinometer
. The percentage difference using the measured average fluence rate as a basis was less than 10% for all measurement methods used.
In Estonia routine broadband direct solar radiation measurements with the Yanishevsky thermoelectric actinometer
started at Tartu-Toravere Meteorological Station (58.25[degrees]N, 26.47[degrees]E) already in 1950.
Its photoreactivity was first discovered in 1833 and it was later suggested as a chemical actinometer
for light intensity measurements.
The incident radiation intensity on the photochemical reactor in the UV region of the electromagnetic spectrum was measured actinometrically using 2-nitrobenzaldehyde (purchased from Sigma-Aldrich) as the chemical actinometer
, and it was found to be 16.5 [10.sup.-5] einstein/[m.sup.2].
Apparently due to a wider than traditional field of view (FOV = 10[degrees]) of the Toravere actinometer
AT50, values of the broadband direct beam in our database are slightly overestimated in cases of larger aerosol turbidity.
The photon flux of solar simulated radiation was measured by chemical method--Reinecke's salt actinometer
Total solar radiation has been measured at Tartu-Toravere meteorological station consistently since 1955, mainly with the Yanishevski AT-50 actinometers
and Savinov-Yanishevski M-115 pyranometers.
Prior to kinetic and analytical measurements, actinometries using p-nitroanisole as chemical actinometers
 and also by using a radiometer (Ocean Optics QE65000) were undertaken in order to check for the uniformity of light distribution within all the surface of Suntest simulator.
Until 1996 the Yanishevski AT-50 actinometers
were used, being then replaced by the Eppley Labor.