Some years ago I designed a reflection color densitometer for my color photographic applications and later an UVmeter for measuring incident UV radiation
You can find a lot of possibilities for choosing your UV photodiode sensor at:
TW30SX is blind to visible light and useful for UVA and UVB and it is what I used
Concerning your UV source depends with your application in mind but I can suggest an UV diode with 360nm peak such as Fox FG5L360 for measuring absorption at 360 nm and useful for measuring potasium dichromate absorption peak.I usually use this type.
I include my web where you can see some details about my old luxmeter design but I'm inferring you have experience with electronics. If you feel we can interchange ideas about it please tell me.
From: Erich Camerling <email@example.com>
To: Alt-photo-process <firstname.lastname@example.org>
Sent: Thu, Dec 3, 2009 5:31 pm
Dear users of an UV-densitometer,
Years ago I built my own visible light transmission densitometer.Now I need to build an UV-densitometer.
Therefore I need your help.Can anyone of you tell me what UV-sensor and what UV- light source is used in your
UV-densitometer ? That is the most important fact for me.When you can give me a copy of the circuit diagram I would appreciate that but it is not necessary .
Thanks in advance for you help.