Re: Electric bath? ... X-rays from light bulbs/Tesla Coils

Hi Jeff,

>  Your last comment is most important.  Only 10 minutes of exposure was
>enough to do serious permanent damage.
>  And scarier yet was x-ray treatments that lasted, yes, 10 even 20 or 30

Yes, these high exposures were bad.  The tubes of the time, being of the
"cold cathode" type, had weak vacuums (compared to today's) but enough to
take decent radiographs.  Using the Rhumkorff coils as drivers didn't help
matters much, since they offered a higher current, lower frequency than the
Tesla coils of the time.

>Scary stuff.  Yeah, I lit up a whole collection of antique bulbs with one
>my "Violet Ray" machines.  Essentially a disruptive discharge Tesla Coil,
>output 50,000V 1/2 megahertz, nice 1" painless spark.
>Oddly enough, the small [modern] 7 1/2 watt night-light/christmas candle
>bulbs, with calendabra bases produced the highest about of phosphorescence,
>and the filaments would also light up brightly, my guess here is due to

You discovered the 7.5 watt bulbs too huh.  I think it's because these are
evacuated of all air and just left at vacuum rather than being refilled with
gas.  Yeah, 50 Kv doesn't sound like much but it used to be enough to
penetrate a coffee can ten feet away when I did my experiments.  Of course,
I was about a hundred yards or so away observing the results with a small
telescope (a 60 mm refractor).  Strange setup indeed, but it helped me to
avoid x-ray exposure.  However, even at that distance, my monitoring counter
would still show double the normal background rate at times.

>Also, I have had high vacuum dewar flasks (no electrodes of course!) that
>produced similar effects, connected with nothing at all, or by aluminum
>for condenser effects.

I don't see why not.  You could capacity couple each end and energize with
positive/negative voltages as you did.

>Another weird effect I've noticed in some old bulbs is the lack of green
>phosphorescence but formation of "small white clouds" in the bulbs,
>sometimes with a white line resembling a "line of demarcation" (forget the
>exact term here, in dealing with Crookes tubes).

I used to call this the "northern light" effect.  There would be a
combination of green, yellow and white colors within the bulb.  Pretty, but
did produce x-rays.

>I might get a few high frequency x-ray tubes made, with special anodes and
>cathodes [Crookes Tube ca. 1910 or so] but not vacuumed to the x-ray degree
>but perhaps a Geissler degree of vacuum.

Yes, there seems to be a fairly fine line between vacuum and x-ray
production.  Once you're out of the vacuum range, you no longer have x-rays.
A Crookes Tube would sure look nice and produce some neat effects as long as
you vacuumed it for plasma and not x-ray production.
>Many Thanks,
>Jeff Behary

Have fun, Jeff!