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Home made x-ray machine.

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LAN_403

uzzors2k

Fri Jan 18 2008, 08:32PM

Registered Member #95 Joined: Thu Feb 09 2006, 04:57PM
Location: Norway
Posts: 1308

There's a lot of great stuff on your site Leslie, but you have to keep filling it with content! I like your page on flash driving common tubes. I've got a 2X2A and CV1290 which I plan to try with a Marx generator. When I experimented with the CV1290 and my SSTC it was producing enough radiation to trigger my Geiger counter, but the ZnS screen I was using wouldn't fluoresce. Not enough energy I would guess, but then again it's made from CRT phosphors.

Can your flash-driven 6EN4 and such fluoresce x-ray intensifier screens, or is long term photo paper exposure required?

Also do you have any more info on your Marx generator, your HV section is somewhat empty.

plazmatron

Sat Jan 19 2008, 12:09PM

Registered Member #1134 Joined: Tue Nov 20 2007, 04:39PM
Location: Bonnie Scotland
Posts: 351

Yes your right, it does need updating!
ZnS doesnt fluoresce very well under x-radiation, unless its silver doped.
A far better alternative is Calcium-tungstate (CaW04).

The 6EN4 driven in flash mode will excite x-ray screens, and these were used to make the exposure on the photographic paper. Screens show up on ebay really cheap at the moment as everyone is switching to digital, so cassettes are surplus.

I will update the site on Monday in respect of the Marx Generator (I`m away from home right now)

Leslie

Mates

Mon Jan 21 2008, 06:53PM

Registered Member #1025 Joined: Sun Sept 23 2007, 07:53PM
Location: Czech Rep.
Posts: 566

Ok, my first try of X-ray photographs. I used the Fly-back as the "photomodel". I always wanted, to see what's inside...

Settings: 150KV, 1mA
Exposition times: 5s (pic2), 20s (pic1) and 1min(pic3)

Next time I'll remove the ferrite core and hopefully I'll see the diode.

BTW: the windings seperation looks like that the design of modern fly-backs is similar to spiral line generators ("Fitch"). Then it would mean that all windings are separated by a diode which are connected in series.What do you think guys?

Cheers
Mates

Dr. Dark Current

Mon Jan 21 2008, 07:19PM

Registered Member #152 Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384

Mates wrote ...

Then it would mean that all windings are separated by a diode which are connected in series.

That's right.

c4r0

Mon Jan 21 2008, 08:18PM

Registered Member #151 Joined: Sun Feb 12 2006, 02:53PM
Location: Poland
Posts: 153

And this schematic proves it:

Mates

Mon Jan 21 2008, 10:31PM

Registered Member #1025 Joined: Sun Sept 23 2007, 07:53PM
Location: Czech Rep.
Posts: 566

c4r0 wrote ...

And this schematic proves it:

I see I just discovered America

In case any of you have any suggestion what else to put under the X-rays I can try itâ€¦ Of course it must be something commonly accessibleâ€¦
Cheers Mates

Hazmatt_(The Underdog)

Tue Jan 22 2008, 08:23AM

Registered Member #135 Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735

how about a disposable camera.

plazmatron

Tue Jan 22 2008, 11:46PM

Registered Member #1134 Joined: Tue Nov 20 2007, 04:39PM
Location: Bonnie Scotland
Posts: 351

Wow mates! that was quick! Well a whole new world awaits you!

I tried to update the site on monday, but it seems, I have exceeded my bandwidth, which is odd!

Anyhow, I will update as soon as!

What tube and power supply are you using Mates?

Mates

Wed Jan 23 2008, 09:18AM

Registered Member #1025 Joined: Sun Sept 23 2007, 07:53PM
Location: Czech Rep.
Posts: 566

plazmatron wrote ...

What tube and power supply are you using Mates?

The tube: MXR-161, water cooled, 160KV, 3000W, from COMET AG Switzerland,
HV source: HF (15KHz) CW multiplier, 5-160KV, 0.5-50mA, 3.2KW

It is an industrial unit I'm using routinely at work and I'm also responsible for the maintenance of this machine...

BTW: At home (in Czech rep) I have one more roentgen which was released form service at our university and I saved it from sending it to the waste dump. There were 3 completely new 2KW water cooled tubes enclosed (made by Chirana). I plan use this parts and built home X-ray source after my mission in Denmark is over...

plazmatron

Wed Jan 23 2008, 12:27PM

Registered Member #1134 Joined: Tue Nov 20 2007, 04:39PM
Location: Bonnie Scotland
Posts: 351

Wow thats some piece of kit! I have never had watercooled tubes before, hence my low beam currents, and long exposures to keep thermal loading to a minimum.

Heres a picture of one of my larger dual filament oil-cooled tubes:

It is just over 6 inches long, and quite heavy. There was no manufactures mark, so heater voltages, and anode voltage were found by experiment, to be 2.5v for heaters, and 150kV max at the anode.

Leslie

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