Step 18: Assemble the Radiating Head

Atmospheric air has a dielectric strength of 1.1 million volts per meter despite what Wikipedia argues. This translates to 11kV per centimeter, or 6kV with pointed electrodes. Since reliably insulating 75kV using air would require a distance larger than 10cm,
making an x-ray device compact is near impossible.

That is of course, if one does not use insulating oil!

Most oils have a dielectric strength 4 times that of air, and eliminate the corona losses which would otherwise occur in an open air design. This reason, coupled with increased thermal conductivity is the reason why nearly all x-ray machines insulate all of their high voltage components with oil, and why both mine and yours should follow suit.

A junction box does a fine job of housing the EHT components. [Image 1] displays the junction box which houses my machine's Coolidge tube, its lead shield, the voltage multiplier and a 1.8 billion ohm resistor to measure the anode voltage. A 90kV this resistor will leak the 50uA needed to fully deflect a galvanometer.

The thickness of the box’s wall will attenuate the x-rays somewhat so there likely won’t be any low energy rays escaping.  Depending on what you want to do this may or may not be a problem, but, x-rays with energies higher than 30keV should still be able to penetrate that thick plastic.
<p>This is the best summary of radiation and high energy particle physics I have ever encountered.</p>
I scrap CT, x-ray systems, MRI anything in hospital radiology.<br>I have tons on HV tanks, caps, transformers etc......... lots of it is obsolete for the market. I am in Pompano Beach FL. I end up throwing out tons, literally tons of equipment. Anyone who wants this stuff please contact me at:<br>Berry7769@gmail.com. if you are seriously tech, i have programable controllers by the dozen. Would love to trade tech repair time for these parts. Hackers and engineers invited.
I live in lithuania (europe, balkan states) if you still have some coolidge tubes from CT scanners I would like buy one (or two) if you would ship them to my country.
<p>Instead of using an expensive ZVS cant you just use a Joule Thief?</p>
<p>Actually i enjoyed this instructable. If it were possible i'd like to ask a few questions and open a dialog. Thanks</p>
<p>Actually i enjoyed this instructable. If it were possible i'd like to ask a few questions and open a dialog. Thanks</p>
Welll....good but it would have been better if u just made an instructable to produce microwaves or how to make a herd gun or something fascinating.....this is good but not of much use....non-ionizing radiation atleast fascinates and fries up electronics too!!
<p>I know how to design the Cockcroft&ndash;Walton multipler for a Iload continous, but how to design for x-ray? I know for example that in x-ray system is possible to use the following parameter kV=100, mA=300, ms=100... but if I design the multiplier for 300mA I think that is not a good design...</p><p>Who can help me for solve this my problem?</p>
A serious project. Well done!
There is a third way of reading thats in between film and fpd and it's cr. Cr is basicaly a reuseable film cassette thats read in a cr machine. Still expensive but is being phased out in favor of fpd. A fourth option is to have a fluoroscopy type setup and put a ccd camera with the II screen. Great job I can barely keep the damn things running when they're made professionally.
<p>grenadier, my jaw is dropped down to the floor reading this. This is like the very last episode of the series X-Files, where everything comes together all in one episode. I am in awe (that's a suburb of a town in China). : ) My respect.</p>
Holy moly good!But very dangerous too!
Dont know if it is too late, but I want one!
Mr. Kennedy would be proud of this instructable! ;)
hello,I want to know how you radiate heat for X-Ray tube, I&lsquo;m not very clear for it。 thank you very much。
Wow! You really know what your talking about! How smart are you?
I don't believe it's possible to quantifiably answer a question like this.
this is what i hate about people who, do such projects, they obviously know what there talking about, but leave out the necessary details for others to follow them.. <br> <br>for example if you wanted to do a proper job of it then the following would be needed:- <br>1) use a singular international supplier (such as RS components or Farnell) and list the parts required to complete the project. <br>2) dont guess components, they should be available off the shelf and available to all, not bulbs tubes and valves that you have gathered together for your own use, where did you get them and can more be purchased (from an international supplier). <br>3) costing,, im not made of money how much does this project cost in total?? $50000 or $50... i want to know in advance rather then start a project and find out i cant get the stuff or its too expensive so i have to abandon it mid way through. <br>4) last buy by no means least,, a Full circuit diagram.. not sections separated out over many web pages, but one full circuit diagram showing everything!. <br> <br>if these simple rules are followed i believe many users would vote in greater numbers and the topic/ your work would be greatly upheld, as its simple to follow, simple to order and compile the parts, its easy affordable by those who wish to start the project and its available to all on the web, due to the use of international suppliers. <br> <br>and now i would like to say that i loved the project, really i do, but i would like to do it myself, but like all consumers of information; i just want everything in front of me before i reach into my pocket and buy the parts. Is that too much to ask?
These people leave out all the details to prevent those who are unwilling to figure them out from completing the projects. Sure, knex guns are one thing, but I wouldn't want every 12 year old kid from here to ɐıןɐɹʇsnɐ shining ionizing photons on their hands...
Perfect, well explained. I would love to try, but I don't have the right knoledge to do it. Anyway, congrat's dude, that's awesome!!
While I don't think I'll be building this one any time soon, I'd like to say thank you for a most fascinating read. I think I've learnt more reading this instructable than I ever did at school when we were supposedly learning about radiation! <br> <br>Beautiful images too!
You get my vote. <br>This is the finest example of how an Instructable should done and presented. <br>Good luck with the printer.
Very nice! I like your writing style and you've covered everything that could be needed.
And they say radical bombardments of radiation will fix your cancer..... <br /> <br /> <br />Go figure. <br /> <br />
The radiation therapy used to treat cancer is of a much different nature than x-rays. At Fermilab they even use neutron radiation as a therapy. It seems to work pretty well at killing tumors (well pretty well compared to everything else we have), but yeah it is kind of ironic.
Awesome instructable, you also have my vote, one thing though: <br>&quot;uranium reactors neutron radiation is not much of a concern, but nonetheless it is best shielded with light materials of all things, materials such as water and aluminum &quot; <br> <br>I'm under the impression that water is used as a moderator, slowing neutrons down to thermal energies so that they can cause induced fission but not as a shielding material, it doesn't absorb neutrons hence it's use as a moderator. Aluminium is a good shielding material AFAIK. <br>
Okay, so I am about to embark on some &quot;prior career geek-dom.&quot;<br> <br> The primary method (ie cost effective) method on shielding neutrons involves subatomic billiards. Not gonna give ya the full lecture, thats what the google-nets are for, but I will put you on the path.<br> <br> &quot;Tell no one that I have put you on the path.&quot;<br> <br> Shielding is rated in &quot;tenth thickness.&quot; How much of a material is required to &quot;alleviate&quot; the radiation field to one tenth of it's original value. Okay, big word, alleviate. Since Roentgen the 13th has already nicely explained the particulate nature of radiation, I will merely extrapolate.<br> <br> Neutrons are already everywhere, but they are not dangerous. They have been captured. How were they captured?<br> <br> Neutron radiation occurs rarely in nature, as a decay path in a couple of minerals. But it always happens in the core of reactors, sorta a requirement. U-23x needs Neuts of specific nrg levels in order to &quot;chain react.&quot; An atom has to be hit with a bullet of just the right speed in order to break apart the figgy puddin on the inside. Too fast and it goes right through. Too slow and it gets sucked in or bounces off. There is a name for this nrg level that is &quot;just right.&quot; Not to hot, not too cold, but just right Goldylocks. It's called, &quot;thermal nrg.&quot;<br> <br> &quot;But ladies, if ya smack that sukka just right, blam, watermelon pie.&quot; -Gallagher.<br> <br> U-23x splits in twain and statisticaaly usually spits out a Neut at about 2.03 MeV (Mega electron Volts)( Roentgen the 13's lil widget extroidinaire is poking around at nrg levels one hundredth of this. But anyway...) Back to alleviatin those pesky Neuts.<br> <br> Fission trons, bad. so lets slow em down. Let's moderate, or alleviate 'em. Water. Good ole Dihydrogen Oxide. Billiards again! {Newtownian mechanics ALERT!<br> <br> &quot;DANGER, DANGER, DANGER WILL ROBINSON!&quot;<br> <br> Collisions. Inelastic collisions, and elastic collisions. Where objects of roughly the same mass collide, they share nrg rather well. What is the mass of an Hydrogen nucleus? Elementary my dear Watson. About twice that of those pesky Neuts zipping around. It takes, on average, 16 collisions for the thing to slow down to the right nrg level for the next phase.<br> <br> Absorption.<br> <br> Thermal neutrons have an nrg around 1eV.<br> <br> Sulphur, Nickel, Germanium are the ones I remember topping the absorption chart. But hey, these aren't in the reactor. But a lot of water is. And, oh yes, waters Hyrdogen absorps the neutrons too. Not as well. But when you got that much, the job gets done.<br> <br> A very condensed version of the path can be located at:<br> http://en.wikipedia.org/wiki/Neutron_capture
Water can be used as a moderator, but enough of it will slow a neutron to a dead stop. Heavy water just does this faster.
IIRC, light water does absorb a bit of radiation, but is quite a good moderator. Heavy water is a poorer moderator (need more of it,) but it absorbs much less radiation. Heavy water can be used with less enriched uranium because it absorbs less radiation. <br />Graphite is also a very efficient moderator, but it's not an inherently stable moderator, unlike water, and it also has the tendency to crack/catch fire/explode when things go very wrong.
This instructable is well thought out, written, and presented to convey the knowledge you have in this field. Very impressive! <br> <br>I got several ideas from your ible and am planning another of my own. I do hope you win a prize for this one too. <br> <br>Great Job!
Great Ibble', but too big a bite. Well researched! Chop it up into chapters and it'll be more educational.
THE FIRST X-RAYS / LOS PRIMEROS RAYOS X <br>Impresionante!!! <br>Rontgen descubri&Atilde;&sup3; los Rayos X (1895) usando un tubo Crookes, el Coolidge fue inventado en 1913. Es f&Atilde;&iexcl;cil simular un tubo Crookes con un tubo de vac&Atilde;&shy;o. Un polo es el catodo y otro es una pelicula de alumnio exterior. No necesita alimentar el filamento de caldeo y la alta tension se dispone entre la placa exterior y el catodo. El tubo Cookes es un tubo de descarga. Todas las medidas de protecci&Atilde;&sup3;n son aplicables. <br>---------------------------------------------------------------------------------------------------------- <br> Amanzing!!! <br>Rontgen discovered the X-Rays (1895) using a Crookes's tube. The Coolidge's was invented in 1913. I think is easy build a Crookes's tube with a power tube. A pole is the catode and other is an aluminium film external the tube. Don't need to heat the tube then d0n't conect the filament. ( easier). <br> <br>The high voltage direct or alternative, is conected to the catode and the external aluminium film ( external plaque). The Cookes tube is a discharge tube. <br> <br>ALL PROTECCTION MEASURES MUST BE USED. <br> <br>http://en.wikipedia.org/wiki/Crookes_tube#The_discovery_of_X-rays <br> <br>Thanks <br>
I need Coolidge tube,how much cost it? <br>i'm from india
Awesome! I saw you in the popular science magazine! <br> <br>-Doctordv
Cool and dangerous :) <br /> <br />
Very interesting. I would have voted for you if i had know about this before the contest ended. Great instructable though
I love how well done this instructable is! I'm especially pleased with how thoroughly you explain the function, dangers, and safety procedures concerning ionizing radiation. Hopefully you get that printer, I think you deserve it!
Thanks! I am not interested in building an XRay device, but the voltage multiplier design you present will work to pump my laser array in the best way to polarize the M. Fermions in my inducer grid. The dimers are not stable, but software tailored will seek a corresponding &quot;working triad&quot; of stable dimers will mate well with the laser fire sequence. I can't afford exotic equipment/tools and must jury rig it to create and sustain an electrical current dynamic in the element arrangement. FREE energy isn't a pipe dream... and you, Sir, provided me the simple end of the tool by which I will change the world. The device shape is a torus.
Fantastic instructable. You have my vote and 5*. <br> <br>Very good explanation of the electronic design. <br> <br>When i was around 11, i met a guy who teached me the basics in electronics. <br>(That was around the time the internet (not http://www.) was invented. <br> <br>He had salvaged Roentgen devices, that had been used by shoe dealers to check, if the shoes fit. <br>I don't exactly know, when they stopped using them. It was before my time... I guess it was in the early sixties. <br> <br>He also used them for photographs in a big lead-clad wooden box. <br>Mosfets haven't been en vouge back then. <br>But he was very fit in all things electron valves. He learned electronics, when the first transitors became available... <br> <br>One of the best instructables i've seen. <br>
They stopped using those when shoe sellers started to get foot cancer. Those fluoroscopes usually had no shielding, and would often spew out 2R/min!
What a read! I'm most impressed with the effort that has gone into this, best of luck with the competition!
Took a whole two months to write :-)
Instructable my arse this is a scientific paper. Great job !!! Got my vote.
I spent the last hour of work reading this. Great work!
Good gosh do I love mad scientist instructables! <br> <br>Bravo!!!!

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Bio: Physicist
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