I am planning to do a phototoxicity experiment in which I need to apply an UV Energy lower than the highest non citotoxic energy. Based on literature it should be around 5J/cm^2 for my cell line so I dont know if I can use my UV lamp and at which distance (5 cm or more) in order not to kill the cells with the irradiance. Could someone help me with the calculations?
The most accurate way is to use a UV power sensor to measure directly. Not sure what the cheapest option is but we use the following one:
https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=3341
There might be other ways to estimate, but this is probably the most consistent and reliable as power may change with the life of the bulb as well.
Hope this helps!
Hallo Eloy,
a lot of parameter to answer your question are unknown.
First: The arrangement of your radiation source with respect to your lamp must be known. Lets assume, in a distance of 5 cm the whole emitted UV-energy is absorbed by your sample.
Second: 5J is a very low energy. 5J in 50min = 50*60s = 3000s corresponds to a power of 5J/3000s = 5Ws/3000s = 1,66 mW. Usual UV lamps have a power in the Watt range. Perhaps you use a LED (light emitting diode or laser) as it is used for microscopes. Or you must reduce the power by filter.
Third: You must correctly test your experiment like proposed by Joseph de Rutte.
With regard
R. Mitdank
Thank you so much for your answers Dr. de Rutte, Dr. Mitdank and Dr. J Byrne. I think my choice will be to get a UV sensor, as it is the most accurate way to adjust the UV irradiance in order not to kill the cells.
Thank you again for your time
Eloy Pena
I think the best way could be to use a spectroradiometer which is able to measure the exact output of the lamp nanometer by nanometer along the spectral range of the lamp. In this way you are able to calculate the integral of the lamp output.
The use of a broadband sensor could be a problem. For example you can't use an UV sensor calibrated for ambienet UV radiation (solar radiation) TO MESURE THE OUTPUT OF A LAMP. Each broadband UV sensor is calibrated for a specific radiation spectrum.
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