
#1
Aug1309, 03:52 PM

P: 1

Dear forum members,
I would like to ask some help regarding irradiance calculation. I am a high school student doing a project in biology in which I expose drosophila m. (fruit flies) to UVA radiation and I would like to mention in my paper the actual dose that was used. I know that... UV dose (J/m^2) = W/m^2 x s W/m^2 refers to irradiance, this is the formula that I found for calculating it: E= dΦ / d Ad 1. Ad is the area which is exposed to the radiation. What does the d in front of Ad stand for? dΦ = E0 cosθ d Ad So, the formula above is the radiation intensity (W)... 2. E0 is the irradiance of light incident upon material, how do I calculate that? From here I found the information: http://metrology.hut.fi/courses/S10...ADIOMETRIA.pdf (on the 5th page) Lamp: Original Philips UVA Type HP3147/A 220V ~ 50 Hz 75W Thank you for any advice and help! 



#2
Aug1309, 08:56 PM

P: 406

W/m^{2} means energy over a certain surface ( which in the case of a fruit fly is less than 1.5 mm^{2} )
Energy is computed by power and distance ( from source to target) with the illusive reflectivity taking it's tole. 



#3
Aug1509, 10:20 AM

Sci Advisor
P: 5,468

Another wrinkle if your source is a fluorescent bulb (long and thin, not like a short arc or an incandescent), and if there are optical elements that refract or reflect some of the light toward your sample, you need to first calculate how much flux is passing through your sample plane. The rough calculation is fairly simple what fraction of the total output is directed at your sample is usually sufficient and if the illumination is fairly uniform, that simplifies the calculation even more. Hope this helps... 



#4
Dec1410, 05:46 PM

P: 1

UV and irradiance
So, if I want to calculate the UVB irradiance, I need to consider the sum the irradiance from 290315 nm?



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