x-ray tube voltage? / High Voltage / Forums

Forums

4hv.org :: Forums :: High Voltage

« Previous topic | Next topic »

x-ray tube voltage?

1 2 3 next

Move Thread

LAN_403

alf

Tue Jun 28 2011, 12:18PM

Registered Member #3925 Joined: Fri Jun 03 2011, 10:50AM
Location:
Posts: 121

hey,

i read somewhere, that it would be possible to use an old vacuum tube, (with tin foil wrapped round the end as an anode) as an x-ray tube, and the x-rays would be generated when the electrons strike the glass, is this possible?
and that voltage would be necessary to generate x-rays in such a configuration?
i guess i could use a marx generator connected to the fbt output, to boost the voltage to a high enough voltage for the x-ray tube.
every capacitor in a marx generator will only need to be rated to the supply voltage right?
and the time between pulses from a marx generator, depends on the capacitance (lower capacitance - higher pulse frequency)
right?

thanks. Alf.

Thomas W

Tue Jun 28 2011, 02:35PM

Registered Member #3324 Joined: Sun Oct 17 2010, 06:57PM
Location:
Posts: 1276

i dont know much about the topic but i think in a marx generator every capacitor has to be rated the Vs*2 and add a bit of extra voltage for safety :)

hboy007

Tue Jun 28 2011, 04:49PM

Registered Member #1667 Joined: Sat Aug 30 2008, 09:57PM
Location:
Posts: 374

like riding a bike

Daedronus

Tue Jun 28 2011, 10:10PM

Registered Member #2329 Joined: Tue Sept 01 2009, 08:25AM
Location:
Posts: 370

Tom Williamson wrote ...

i dont know much about the topic but i think in a marx generator every capacitor has to be rated the Vs*2 and add a bit of extra voltage for safety :)

I think that was for the CW generator. Marx looks like it needs just Vs + safety margin.

also...

Proper X-Ray tubes are cheap, I would not bother with a light bulb or vacuum tube.
if I was interested in X-rays...
and I'm not...
because they scare me...
I would want one or two detection devices before I ever attempted to produce x-rays...

H8erade

Tue Jun 28 2011, 10:19PM

Registered Member #3451 Joined: Sun Nov 28 2010, 11:13PM
Location: United States
Posts: 100

hboy007 wrote ...

like riding a bike

Thanks for that. I was wondering about light bulbs and x-rays a few days ago.

alf

Wed Jun 29 2011, 10:21AM

Registered Member #3925 Joined: Fri Jun 03 2011, 10:50AM
Location:
Posts: 121

hboy007 wrote ...

like riding a bike

haha allright. i shall try it with a vacuum tube :P

alf

Wed Jun 29 2011, 10:24AM

Registered Member #3925 Joined: Fri Jun 03 2011, 10:50AM
Location:
Posts: 121

Daedronus wrote ...

Tom Williamson wrote ...

i dont know much about the topic but i think in a marx generator every capacitor has to be rated the Vs*2 and add a bit of extra voltage for safety :)

hey,

hmm they dont seem so cheap on ebay lol, where have you seen cheap ones?
haha i have a gieger counter, i trust it to be reliable haha,
is x-ray phosphor availible, that can be reused, instead of film?

thanks. Alf.

Daedronus

Wed Jun 29 2011, 12:47PM

Registered Member #2329 Joined: Tue Sept 01 2009, 08:25AM
Location:
Posts: 370

Yes, far more expensive then a light bulb, but probably they also work better...
I don't really know for sure, this is not my usual playground....

alf

Wed Jun 29 2011, 07:51PM

Registered Member #3925 Joined: Fri Jun 03 2011, 10:50AM
Location:
Posts: 121

Daedronus wrote ...

Yes, far more expensive then a light bulb, but probably they also work better...
I don't really know for sure, this is not my usual playground....

haha yeah i would guess so,

thanks for sending that link :D, they are pretty cheap, but since the p&p to the uk is probably quite expensive... lol

thanks. Alf.

Xray

Thu Jul 07 2011, 08:46PM

Registered Member #3429 Joined: Sun Nov 21 2010, 02:04AM
Location: Minnesota, USA
Posts: 288

alf wrote ...

hey,

i read somewhere, that it would be possible to use an old vacuum tube, (with tin foil wrapped round the end as an anode) as an x-ray tube, and the x-rays would be generated when the electrons strike the glass, is this possible?
and that voltage would be necessary to generate x-rays in such a configuration?
i guess i could use a marx generator connected to the fbt output, to boost the voltage to a high enough voltage for the x-ray tube.
every capacitor in a marx generator will only need to be rated to the supply voltage right?
and the time between pulses from a marx generator, depends on the capacitance (lower capacitance - higher pulse frequency)
right?

thanks. Alf.

I made my first "X-ray Machine" about 30 years ago. It was powered by a small Tesla Coil, and the "X-ray Tube" was an old radio tube (type 01A). You do not need to light the filament in the tube, and therefore it operates as a cold-cathode X-ray tube. In fact, ALL four pins of the tube were tied together, and the hv was applied to them. I covered the top one-third of the glass globe with a single layer of aluminum foil, and grounded it back to the Tesla Coil return wire (the "low" end of the secondary). I mounted the redio tube in a lead cylinder with a half-inch hole in the cover which was my X-ray beam "window".

I was able to X-ray stuff around the house, including a dead mouse still in the trap that caught it. That was an interesting image, and it requried an exposure time of about 20 minutes using Polaroid film. The noise and ozone smell from the spark gap was really annoying but I didn't care. I was just happy that I actually built a working X-ray machine that I impressed my friends and relatives with.

Now that I am in the X-ray repair business, I have access to lots of X-ray equipment. It's an interesting hobby.

1 2 3 next

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob