On 5.1.1998, at 11:47, Andrew Mayo  wrote:
>The tube I use is I think 30W and about 9 inches long. It is a
powerful
>UV emitter used for water decontamination and someone gave it to me
but
>I think they can be purchased for around $50 or so - they are used
also
>as germicidal lamps - check your yellow pages.

There are other fast and *cheap* uv sourses available as well. I've
used eg. mercury vapor lamps (without
the outer glass envelope with fluorescents!!) with good success.
Output for the quartz-only mercury vapor
lamp will be mostly in the uv region (mostly 254, 366 and some 184nm
output peaks). Things like 125W
mercury vapor lamp (plain quartz) make *very* powerfull and very
cheap uv sources! Different ballasts
can be used to lower the output power if needed.

I think main output should be at 254nm peak with this method and
that's exactly what you want for
uv eraser. Soft uv like 366nm peak is no good for chip eraser. With
very powerfull exposure methods
you'll probably get very fast results but take care not to
over-exposure chips!

>Caveats
>
>1. Make sure you shield it so you won't ever look at it - it is very
>powerful and would probably not do your eyes a great deal of good.

That applies with those dirty cheap lamps very well too! 1-2min
exposure at few meters will make severe
burns all over you. I'd avoid all exposure!

>2. Ensure you use such a tube in a well-ventilated area as the ozone
>produced is quite substantial - this is, indeed, why these tubes are
>used for their intended purpose.

Yap, 254nm radiation will make ozon a lot. I think it's the radiation
that kills things when UV is used as
a sterilizing method.


--
Harri Suomalainen     mailto:haba@cc.hut.fi

We have phone numbers, why would we need IP-numbers? - a person in a
bus