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2answers
57 views

What's the meaning of partial derivative for radiance?

The definition of radiance is: $$L\equiv\frac {\partial^2 \Phi}{\partial A\,\partial\omega\,\cos\theta}$$ where: $\Phi$ is the radiant flux $\omega$ is the solid angle $A\cos\theta$ is the ...
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0answers
35 views

Energy dependence of integrating dosimeters

The graph shows the relative response of a dosimeter at different energies, normalized to 1.25 MeV Co-60 gamma rays. Curve A is the graph of the equation $$ ...
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0answers
33 views

Hemisphere irradiance

How do I calculate sky irradiance from radiance (L) from a hemisphere above a surface which is tilted relative to the normal (x=0,y=0,z=1). I have L as a function of zenith (0 to 180deg) and azimuth ...
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33 views

Why do some materials follow Lambert's cosine law?

I perfectly understand Lambert's cosine law, so I can apply it, it isn't really that hard (now that I got it :) $$I_n=I_\theta*\cos\theta$$ What I don't understand is why some materials follow this ...
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0answers
26 views

What exactly is $\theta$ in Radiance formula?

The definition of radiance is: $$L\equiv\frac {\partial^2 \Phi}{\partial \omega\,\partial A\,\cos\theta}$$ where: $\Phi$ is the radiant flux $\omega$ is the solid angle $A\cos\theta$ is the ...
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0answers
43 views

Reflectivity of gases

According to the principle of the conservation of energy, the following is true for an object: emissivity+reflectivity+transmittance=1; where emissivity=absorbtivity according to Kirchoff. When ...