# How can I accurately measure irradiance for my UV sanitization device design?

• tihort
In summary, accurately measuring irradiance for UV sanitization device design involves understanding the principles of radiation detection and utilizing appropriate instruments such as radiometers and spectrometers. It is important to consider factors such as wavelength range, measurement accuracy, and calibration to ensure accurate readings. Additionally, proper placement and orientation of the sensor are crucial for obtaining reliable measurements. Regular maintenance and calibration checks are also necessary to maintain accuracy over time.
tihort
hello.

I am working to understand and design a UV sanitization device.

What is a good resource to learn about irradiance and its relation to distance from a surface.

Secondly, in real life, how is irradiance measured? Given a surface area, I would need to specify bulbs of certain intensity to get the device to work.

Thank you.

http://en.wikipedia.org/wiki/Irradiance has the basics. For a simple source (isotropic in all directions) it is an inverse square law (1/d^2, where d is distance) http://en.wikipedia.org/wiki/Inverse_square_law

For an actual calculation you need to know the power output of the bulbs you are getting within the wavelength band that you need (bulbs usually emit over a wide range of frequencies).

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The wiki article was ok, my gold-standard reference is Wolfe's "Introduction to Radiometry".

As to your second question, it can get a little tricky- you need to know details about the bulb's radiance: how much light goes in what direction. That plus the geometry will tell you how much radiation is incident on your surface.

Irradiance detectors are a fairly standard piece of equipment, but to get highly accurate and precise (<10%) measurements requires some care- spectral characteristics, polariation control, etc. An integrating sphere combined with a stable detector can give 1% precision without too much trouble.

http://physics.nist.gov/Divisions/Div844/facilities/fascal/fascal.html

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## Related to How can I accurately measure irradiance for my UV sanitization device design?

Irradiance is the amount of light energy per unit area that is incident on a surface. It is typically measured in watts per square meter (W/m²) and is often used in the context of UV radiation.

## 2. Why is measuring UV radiation important?

UV radiation can have both positive and negative effects on living organisms and materials. Measuring UV radiation allows us to understand its impact and make informed decisions about protection and exposure.

## 3. How is UV irradiance measured?

UV irradiance is typically measured using a radiometer, which is a device that detects and measures UV radiation. The radiometer usually contains a sensor that is sensitive to UV light and can convert it to an electrical signal for measurement.

## 4. What is the difference between irradiance and UV index?

Irradiance measures the amount of UV radiation that is incident on a surface, while UV index is a numerical scale that represents the intensity of UV radiation at the Earth's surface. UV index takes into account factors such as the angle of the sun and the thickness of the ozone layer.

## 5. Is UV irradiance the same as UV exposure?

No, UV irradiance and UV exposure are not the same. UV irradiance measures the amount of UV radiation that reaches a surface, while UV exposure refers to the amount of UV radiation that is absorbed by the skin. UV exposure is affected by factors such as skin type, time of day, and duration of exposure.

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