Hi All,
Im working on a project where I need to understand the variable UV radiation hitting a surface area of about 0.5m2 from a distance of about 10 meters, expressed in mW/m2.
Ideally, it would be a straight forward scan. If that’s not possible, a sensor that just reads the reflectance could work if I took a baseline reading from a regular spectrometer and worked out the absorption/reflectance ratio.

 

Welcome to AAC.

If you have the budget to buy from a mainline instrument supplier like ILT then contact one and get a sales engineer to help you. If not, you may be best off using a camera an optical notch filter. You can make your own from a low pass/high pass pair depending on the wavelengths of interest.

It would be far easier to help if you explained why you are measuring incident UV light, since that would give a lot more information than speculative questioning (shots in the dark, so to speak) will get in a lot shorter time.

 

Thanks, Ya'akov.
I am working with my local church who have some very old murals painted on to the ceiling. They recieve direct and indirect sunlight as well as artificial light from LED sources.
They have deteriorated over the years and we are keen to limit further deterioration as much as possible while still allowing people to appreciate them.
Because of their location, fragility and public view, I can't mount anything on or close to them. The sensor must be taking readings from about 5 meters away at a minimum, but 10m would be easier.
I need the sensor to take readings and log them every hour over the course of a year, so we can align peak UV exposure to peak visitor times, as well as limit absolute UV exposure.
I am interested in wavelengths between 200nm and 400nm and must be able to account for the differences in colours/absoption which is why i thought an average over 0.5m2 could work. A line scanner type system could also work.

Hope this helps.

 

as well as limit absolute UV exposure.

How will that be accomplished and is that being done now?

 

It is being done now through various methods.
This project is about increasing the effectiveness and ensuring we practically achieve what we think we are theoretically.

 

Methods like window film to block UV?

 

Yes, and others.
My question is not about blocking the UV, it’s about measuring it on a surface from a distance.
Perhaps a Thermopile with modifications to read only within the UV wavelengths?

 

My question is not about blocking the UV, it’s about measuring it on a surface from a distance.
Perhaps a Thermopile with modifications to read only within the UV wavelengths?

I understand that but my point is to spend the time and money on mitigation.

 

It's not a data logger but would something like this Meter work in your research?

 

Thanks, Ya'akov.
I am working with my local church who have some very old murals painted on to the ceiling. They recieve direct and indirect sunlight as well as artificial light from LED sources.
They have deteriorated over the years and we are keen to limit further deterioration as much as possible while still allowing people to appreciate them.
Because of their location, fragility and public view, I can't mount anything on or close to them. The sensor must be taking readings from about 5 meters away at a minimum, but 10m would be easier.
I need the sensor to take readings and log them every hour over the course of a year, so we can align peak UV exposure to peak visitor times, as well as limit absolute UV exposure.
I am interested in wavelengths between 200nm and 400nm and must be able to account for the differences in colours/absoption which is why i thought an average over 0.5m2 could work. A line scanner type system could also work.

Hope this helps.

You have a problem that money would solve, but I suspect that is not an abundant resource for this project.

Here is a low cost sensor from Waveshare the covers 200-375nm, which may be sufficient for your application. The trouble is your requirement for 5-10m distance and only 0.5m². This will require some fairly complex optics, and not just any optics. Because if the poor transmission of ordinary glass at the wavelengths of interest, you will need something made from fused silica, CaF₂ (calcium fluoride), MgF₂ (magnesium fluoride), or a specialized acrylic resin—the last is probably cheapest, it is also the worst performing.

Your requirements call for a seriously telephoto lens, which will contain several elements. This drives the cost up further. I don't really have any useful advice on finds affordable optics. I would start with Edmund Scientific, who do very exotic optics and can offer engineering assistance. I would also investigate modifying a camera module by removing the UV and IR cut filters and replaces them with your own high and low pass filters.

 

I does look like funds will be the limiting factor here.

The Waveshare sensor looks to be capable of everything I need. My partner works with a company designing and producing CaF₂ collimators, so it looks like I have the base ingredients to start bringing it together. Hopefully, within a reasonable cost.

It does suprise me that no one is currently doing a UV sensor with decent optics, not even a laser.