UV lamp sensor circuit for checking the lamp intensity

I have a UV lamp in a exposure box, that takes sometime to warm up (is 1000W), I want to build a circuit to detect the lamp intensity, to adjust the time of exposure.
What type of sensors I can use to accomplish this?, besides a UV sensor cause they cost almost 100USD.

Re: UV lamp sensor circuit

Probably any clear-window photosensor would do. You'll see
some attenuation in the cover glass but that will just be a
constant scale factor. I'd stay clear of plastic encapsulated
ones as these may cloud over time.

An IR or visible sensor with no wavelength filtering will
produce a photocurrent just fine at UV. This current will
be intensity-proportional once you get up out of the
leakage floor and recombination (very low flux). Since
you want an integral (exposure) I'd wire it up with the
photodiode reverse-biased to a decently high working
voltage, and let it charge a capacitor to a threshold
voltage from an initial zeroed state (switch reset) and
a comparator's output can be used as your endpoint
signal. Or you might just look at the voltage on a meter
and press the "off" button.

Re: UV lamp sensor circuit

Maybe to use some black non transparent plate between UV source and PCB like shield, for some time, waiting to UV source get heated up and working with full capacity, then remove out plate and timer starts to count exposure time.

What I know UV photo diode have prices about 30eur and up.

Re: UV lamp sensor circuit

Using visible light intensity as a measure for UV should basically work. Lamp wear may possibly cause a reduction of UV intensity, e.g. absorption by sputtered electrode metal. If you want a precise exposure control, a dedicated UV sensor fitting the photomask sensitivity characteristic may be wanted. I remember that besides specific vacuum photo cells gallium arsenide photo diodes have UV sensitivity and visible light supression without filters.

Re: UV lamp sensor circuit

Thank you for your answer I have found this one
https://www.digikey.com/product-detail/en/TEFD4300/TEFD4300-ND/2987573
and I wonder if that would work ?, any more suggestions on what other sensor I can use from digikey?
The UV sensor I found it works on Wavelength 660nm and Spectral Range 250nm ~ 1100nm
should I just look for that range photodiode/photocell with clear package?

I just want to order a few sensors and try them all at once to see what would get the best results.

I will also plan to use a UV Pass Woods-type Filter if that would help, on the type of sensor I pick
https://www.bhphotovideo.com/c/product/189949-REG/Rosco_120336507508_Permacolor_UV_Woods.html

any links to the type I can use it would help a lot, thank you.

Re: UV lamp sensor circuit

Apparently LEDs also work as photodiodes. Perhaps a UV LED could make a suitable sensor? Whatever the casing's made of, it must be transparent to UV....

Re: UV lamp sensor circuit

If you intend exact exposure control, you need to know the photomask sensitivity curve. Also the design of your exposure box matters. Does it use a glass window?

Re: UV lamp sensor circuit

it does have a glass window, and thanks, I didn't know diode act as receiver also.