chief
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How much Platinum in old crooke-xray-tube's anode ?
Hello again, friends, it's been a while ...
I wonder:
There are 2 quite ugly, old crooke-style x-ray-tubes right on my table here,
==> a bigger one (43 cm from end to end), bulb diameter 15.5 cm
==> and a smaller one (28 cm end to end), bulb 8.8 cm
Now the anode are said to be typically made of platinum, see eg.
http://en.wikipedia.org/wiki/Crookes_tube
| Quote: |
The anode was made of a heavy metal, usually platinum, which generated more x-rays |
I would hate to slaughter these relics, but I could use the money for the platinum ...
The anode-diameters are 2 cm and 1 cm ...
Now: Any idea, how thick they might be ?? Back then (1910s and 1920s) the metal was cheaper ...
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entropy51
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| Quote: | | I would hate to slaughter these relics, but I could use the money for the platinum ... |
It would be a crime
to ruin these. Please don't do it.
And it might be tungsten instead of Pt.
[Edited on 20-1-2010 by entropy51]
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chief
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No tungsten, I've read around, eg.
http://books.google.de/books?id=IXPz7bVR7g0C&pg=PT68&...
I'll try to make photos and find maybe some museum ...
Tungsten wasn't easy enough to work with back then, and Platinum also emitted more efficiently ...
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watson.fawkes
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The Pt content puts a floor on the price, but the tubes are possibly more valuable as antiques over that floor. Crookes tubes, I should remind you,
are officially 19th century and thus eligible for Victorian Steampunk status, which yields a whole new market population of widely-varying
gullibility.
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chief
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I havent made the photos yet, but: The larger one is even a "self-regulating" one, like described on this site:
http://physics.kenyon.edu/EarlyApparatus/Miscellaneous/X%20R...
[Edited on 21-1-2010 by chief]
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chief
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Now the pictures:
http://mister-big-busines.de/crooke-xray/index.html
I pay 25 % provision to anyone who can achieve me a good price ~ ! ~
Measurements as above, contact here or via the private-message- function ...
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entropy51
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The 1917 book "X-rays" by Kaye was a fairly authoritative reference in its time. This book states that the cathode and anode are made of Al. It says
that starting in 1897 the anti-cathode is made of Ni with a 1/100 mm thick Pt sheet covering it. Apparently earlier tubes used more Pt, but this
became prohibitively expensive. It further states that at that time (1917) tungsten had mostly replaced the Ni/Pt for the anti-cathode.
I think more valuable as antiques than as a source of Pt.
Just discovered the Kaye book online here
[Edited on 22-1-2010 by entropy51]
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chief
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How old, by that book, do you think these are ? What wattage ? The larger one, with it's 43 cm of length, looks like capable of handling near 100 kV,
which at 30 mA would give a heat of 3 kW, much of it at the antikathode (alias "anode" or "target"), and therefore require some serious thickness of
the target.
Also the bulb (sized mainly by the heat) with it's 15 cm of diameter is about as large as some old 2000-Watt-incandescent-bulb that I once saw ... ;
not a toy, this tube ... !
The 2 outer electrodes really look like aluminum.
The interesting thing is: On google-image-search there are only a few pictures of such tubes, at all !
Any idea about how rare these are and what I can ask for those when offering to a museum ?
[Edited on 22-1-2010 by chief]
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chief
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The book (link 2 posts above) states plated Ni for cheaper tubes of low output ... ; tungsten on the other hand is brittle, but this target looks
"worked", what do you think (?) :
http://mister-big-busines.de/crooke-xray/00448.jpg
[Edited on 1-25-2010 by Polverone]
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chief
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Here now the downsized images, for the high-res ones go to the gallery
( http://mister-big-busines.de/crooke-xray/ )
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chief
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I thought over it: I prefer to sell those, not to destroy them ... ...
How does 500 EUR for both of them sound ?
Simple to operate: Just diminish the vacuum by heating the substances in the side-tubes a bit, and then plainly connect some HV-source with maybe
10-50 mA capability ...
The polychromatic ray is probably good for some basic x-ray-crystallography ... maybe Laue- or even Debye-Scherrer- experiments ...
Also I thought about an x-ray-flashlight: Discharge some Leiden-bottles into the tube, for single pulses of strong radiation ... ...
Maybe I would trade them for something else, like a really nice Laboratory-furnace (multi-kW), or maybe an working electricity-Generator (preferably
on Diesel) ...
These things are in east-germany ... as well as a couple of other old tubes ...
[Edited on 24-1-2010 by chief]
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dann2
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Hello Chief,
Greetings to East Germany! Original home of the Chlorates Bitterfeld (if I am not mistaken)
While it is not really any of my business, I would be inclined to say that it would be plain WRONG to break up those baby's to get Pt out of them. Try
ebay with a reserve?
Cheers,
Dann2
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Texium
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Thread Moved
19-11-2023 at 15:09 |
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