Instrument - Apogee PS-200 Spectroradiometer with hemispherical cosine corrector

Short name:

Full name:
Apogee PS-200 Spectroradiometer with hemispherical cosine corrector

What is being measured:
Spectral output (energy flux density, photon flux density, or illuminance) of radiation sources for plant or human lighting, reflectance and transmittance measurements of natural and synthetic surfaces and materials (often plant leaves and canopies), and

Sampling Protocol:



Instrument year :

Data recording software:
StellarNet (proprietary from Apogee)

Data analysis software:
Matlab, Excel

Raw data time resolution:
0.5 nm

Analysis data averaging:

Detection limit:
0.2% stray light

Sensitivity to temperature (and correction method, if applicable): :
Not sensitive to temperature within a range of 0-60 Celsius

Sensitivity to relative humidity (and correction method, if applicable): :
Not known to be sensitive to RH

Sampling method:
Fiber Optic camera for the spectroradiometer is placed facing to light surface, at the location where the measurement is desired

Sample preparation method:
No sample preparation

Sample residence time (chamber to instrument) (seconds):

Length of tubing (cm):

Instrument flow rate:

Tubing inner diameter:

Tubing material:

Chemical identification method:
No chemicals are being identified. Calibrated light intensity per area (W/m2) is measured by a CCD camera through a cosine corrector (± 5 % at 80° zenith angle) transmitted through fiber optic to a data logger

Data analysis method:
Data analysis in Matlab. All data were averaged and converted to flux via the equation Photon flux (ph/cm2/s/nm) =(4*pi*r^2/(pi*r^2))*(irradiance (W/m2/nm)*Teflon_corr)/(hc/lamdba)}... where the factor of 4 is the ratio of the flux impinging on a sphere over the circular cross section of the cosine corrector, and Teflon correction is the correction (~0.92) of the diminished light transmission from a dirty Teflon bag material compared to no Teflon.

Quantification method:
The calculated photon flux is quantitatively adjusted by modeling a 100 ppb isoprene + 2 ppm + light experiment. The decay of isoprene and H2O2 were used to understand light flux in the chamber.

Calibration method:
NIST traceable calibration in absolute radiation units for wavelengths between 300 and 1000 nm by manufacturer

Calibration drift estimate:
Low (on the order of weeks)

Calibration schedule:
As Needed

Uncertainty estimation method:
Uncertainty is estimated by manufacturer calibration uncertainty (± 10 %) and the 1-sigma deviation in measurement results at different locations in the chamber (~15% difference).

Known interferences:

Link to supplemental information:

Additional notes:

Measurement uncertainty:

Measurement units:
Wavelength (nm); Photon Flux (ph/cm2/nm/s)

Light Flux Characterizations:
2018-09-18 (#27)