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Technology

Build Your Own X-Ray Machine 96

Posted by michael from the lead-lined-underwear dept.
Mr. Roboto writes "This web site has information on how to build your own X-ray machine from common household parts, inculding a vacuum tube, a few thousand feet of copper and a few other parts. There are also X-rays made of wood, fish and steel. I need to dig out my stash of vacuum tubes now." Unfortunately, I don't count "vacuum tubes" among common household parts, but this would be a great science fair project.
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Build Your Own X-Ray Machine More

Build Your Own X-Ray Machine

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  • source for cheap film badges? (Score:3)

    by green pizza ( 159161 ) on Sunday February 25, 2001 @02:07AM (#404948) Homepage
    Reading that made me wonder... where can one buy some film badges (the sort that radiology techs wear to alert them of excessive exposure) ? Anyone happen to know?

  • This is very dangerous (Score:4)

    by qpt ( 319020 ) on Sunday February 25, 2001 @02:09AM (#404949)
    X-Rays have been proven to cause cancer even when used by professional physicians. Putting them in the hands of every-day individuals is highly irresponsible.

    Our urban environments are already wrought with dangers in the form of guns and drugs. Do we really need gangs roving the streets with high-powered x-ray devices? I think the answer is obviously no, we do not.

    The privacy implications are also troubling. Now, with complete lack of regard to my safety or rights, people can install x-ray machines anywhere - in parks, streets, or their homes.

    I hope the government moves quickly and bans these devices, before their proliferation leads to certain harm.

    - qpt
  • Yeah, theres nothing quite like the rush of knowing you've just permnently removed all of your potential contributions to the gene pool all in the name of extra-credit. =)

    --
  • Nice to know Slashdot is right up there at the forefront of all tech news. 1995 and 1997... Nah, I'm not complaining really. I wish they'd have set it out so it was slightly easier to follow if you were wishing to do it yourself. The way it is written in such a long essay form makes it almost impossible to extract the relevant bits of information. Yes it's nice to know why and how the various parts work, but perhaps the explanation should have come after the rough description of how to construct it.

  • think of the usefulness (Score:3)

    by unformed ( 225214 ) on Sunday February 25, 2001 @02:16AM (#404952)
    if i can make it small enough, i can stick it in my eye and look through guys' pants!

  • Vaccum Tubes are *VERY* common yet. (Score:3)

    by mr ( 88570 ) on Sunday February 25, 2001 @02:22AM (#404953)
    Unless you took your Linux IPO millions and bought a LCD monitor, or live your life out of a lap top, most of the rest of us mortals sit in front of a vaccum tube based CRT and bathe in (reduced) radiation all day long.

    Monitors have lead in them for a reason. And its the same reason if you plan on building an x-ray machine, you had better be damn careful...radiation is harmful. Hopefully the fact you can't just D/L this and run it will keep it out of the hands of irresponsible boobs we'll call xray kiddies.
  • Simons prefers to stick with Oudin coil. It is easily constructed with hand tools. The job is simplified if you can lay hands on a vibrator of the type used in the spark coil of a Model-T Ford.

    Well it's a good thing I've got one of those lying around in my garage!

  • Science! Oooohh! Pretty shiny things! The light!

    Slashdot Babelfish

  • Re:This is very dangerous (Score:3)

    by dair ( 210 ) on Sunday February 25, 2001 @02:36AM (#404956)
    Do we really need gangs roving the streets with high-powered x-ray devices?

    I think you'll be fairly safe - they also have to strap a large photographic plate to your back, then wait a couple of hours to have it developed. You'll probably notice.

    -dair

  • Re:This is very dangerous (Score:1)

    by Anonymous Coward
    Our urban environments are already wrought with dangers in the form of guns and drugs. Do we really need gangs roving the streets with high-powered x-ray devices?

    "gimme your nike's or i'll zap you with this and you'll run a slight risk of becomming sterile or slowly developing cancer" uh oh!

    Also someone could build a giant x-ray machine in a park or the street but why? I don't know where you're from but evil scientists aren't much of a problem here in canada. maybe you should have been around like a hundred years ago to protest this.
  • For those of you who are going to try this, here are the symptoms of high frequency radiation exposure:

    Headache
    Stomach ache
    Nausea
    Unconsiousness
    Death

    Somewhere between Stomach ache and death comes sterility. Don't ask me why but I have a friend with silicone testicles and testosterone shots for life courtesy of radiation exposure and the US government.
  • Of course one good use for this would be to save the wait at the hospital. Injured your ankle (like I did a few years ago and couldn't get to the hospital)? Screw waiting 6 hours for a bloody x-ray at the local ER, check with your homemade x-ray machine. VOILA! You can see if you're ankle's broken or not...

    Just a shame you can't have kids now after using it...

    ---

  • I don't think you have it right. The article means traditional vacuum tubes - which are found in old radios and old TV's (pre-transistor electronics). They have not been common for a long time. A CRT tube is a vacuum tube, but it is not what is needed for this project.
  • Talk about your knee jerk reactions. How about you go RTFA and come back and realise what idiotic comment that truly was. These machines can penetrate a bit of wood an inch thick, or a piece of very thin steel.

    Gangs roaming with high powered x-ray - what?

    I mean really, banning a small amatuer device for taking harmless little x-rays - this is boyond incredulous. And I really cant see people installing these tiny x-ray machines in a park just so that you wander into a stray x-ray's path, oh what a prank! You must really have a low opinion of society if that is the first thing you can think of, and I really wonder how you can function in a society that you feel is that demented, there is alot of easier and more effective ways that we are all plotting against you.... why just think of all the home made BOMBS that we must have laid out to get you!

  • This person's comments are up to a rating of 4 - informative?

    When did the slashdot moderators become such a bunch of uninformed ludites? Next they'll be wanting to protects us from computers and other evils of technology ;-)
  • Don't ask me why but I have a friend with silicone testicles and testosterone shots for life courtesy of radiation exposure and the US government.
    And the scary part is that your friend is female, right?

    --
    Ellison: How are you gentlemen !! All your database are belong to us

  • Our urban environments are already wrought with dangers in the form of guns and drugs. Do we really need gangs roving the streets with high-powered x-ray devices? I think the answer is obviously no, we do not.

    Hmmm.... First, these seem to be fairly high-powered and so require lots of electricity. I have a hard time imagining gangs roving the streets with X-ray devices and even if they did, they would probably be a bit less effective than their guns, so I don't think that the trend would last....

    The privacy implications are also troubling. Now, with complete lack of regard to my safety or rights, people can install x-ray machines anywhere - in parks, streets, or their homes.

    Again, this poses some serious practical problems. One would need to set up a photographic plate ahead of time, wait until you were on the target, hope you don't move while the picture is being taken, etc. THe plates do have to be quite close to the target, so the practical difficulties here are formitable.

    I don't deny that the operation of these devices poses some risk. However, I think you have well overstated your case.

  • Whelp, it's time to drag out my lead underwear... This could be fun. I think I will be making one to find where in the hell my keys are...

    political message:
    Support the GPPTF Gene Pool Protection Task force
    -----------

  • I hope the government moves quickly and bans these devices, before their proliferation leads to certain harm.

    I am certain that this is already illegal. I know for a fact that all devices in Australia that produce over a certain amount of ionising radiation have to be registered. There is strict control over unautorised access to labs with radiating apparatus, personal radiation radiation monitoring must be in place and every precaution must be taken to avoid accidental exposure.

  • Unfortunatly the film badges will still only alert you to the danger after it is too late (once developed). There are electronic personal dose meters available that give you an instant readout of the amount of radiation you are recieving and keeps track of long term exposure.
  • I think you need help! Tech
  • It looks like it's not a bad system if you're only interested in low atomic number materal (Z>15). It should be quite sufficient for bio. samples.

    One major improvement would be to eliminate the need for film (which can be extreemly expensive). One could use a phosphorus screen with a camera behind it to capture the images. I'd probably use digial as I'm uncertain what x-rays do to the magnetic films in VCR tapes.

    I worked at a research center which had a setup like this. Using an automated stage, digital video, and basic image analysis (simple averaging) we were able to make some very nice movies.

  • The radiation exposure badges are often supplied by some sort of government or highly regulated agency charged with the job of monitoring occupational exposure to radiation.

    In Australia there is the Australian Radiation Protection and Nuclear Safety Agency. Essentially this provides the badges (at a cost) and performs the regular ( every 3 months at the most) measurement of dose.

    This measurement is added to a file of your lifelong exposure to radiation(in Australia only). So anytime you can find out how much radiation you have received from work over your lifetime, and for continuing studies into the effects of low level radiation, like how much does one mS a year increase our chance of cancer.

    Usually this service is supplied to people who have some sort of reason to work with, and also accreditation to use radioactive sources. So this could be difficult for backyard experimentors.
  • ...but this would be a great science fair project.

    Yeah, and then little Johnny (or Joany or chocci or whatever) wouldn't have to worry about funding their University education because the leukemia would get them long before their freshman year.

  • AED Dosimetry [aeil.com]

    Is $16 cheap for a film ring? Probably cheaper than long term, low dose exposure.

  • Re:Improvements (Score:1)

    by Anonymous Coward
    NO!!!! Phosporus screen was the old style of device. Film is much more sensitive so you get much less exposure. You do not want to be in the same room as the machine this guy built. His machine was measured to produce 750 mrad/min at three feet, which by today's standards is f*cking huge. That is how he got such high-contrast pictures with very primitive equipment. I mean, we are talking about an amateur in the 1960s, so those pictures were probably taken on visible-quality NaI film!

    However your idea of digital is better. The good answer is to use a CCD array tuned to x-ray and shielded from visible light, and have it next to the object examined. In some clinics doctors use this kind of device to see and manipulate hand, arm, foot, etc. It is impractical for chest etc. of course and does not yet have the resolution of film. Also since a lens will not work for x-ray, this is basically just a projection just like a standard x-ray, and so you need a lot of CCD... as you may imagine, this is very expensive. Few American hospital clinics have this, but if you are in a big city in the US and are unlucky enough to drop something very heavy on your bare foot, you may see one yourself.

  • Classic Slashdot (Score:5)

    by shambler snack ( 17630 ) on Sunday February 25, 2001 @04:27AM (#404974) Homepage
    Is this another example of it doesn't matter (or even exist) unless it's on the web? Note at the bottom of the page where this was take from:

    The preceding was taken in full from
    Section IX. Optics, Heat, and Electronics;
    Chapter 3. An Inexpensive X-ray Machine
    The Scientific American Book of Projects for The Amateur Scientist
    Library of Congress Card Catalog Number: 60-14286
    © Copyright 1960 by C. L. Strong

    My father got me this book in middle school (for me, the mid-60's), and I used a number of the projects as starting points for my own hardware hacks. The most notable was the simple wind tunnel that used burning cones of incense to create streamers of smoke in the tunnel chamber. It was powered by a vacuum cleaner. I spent a fair amount of time making sure that air entering the chamber was even across the plenum. Another Scientific American experiment I started with was the construction of an electrostatic motor. I built a large one from plexiglass (12 inch diameter rotor, 18 inches long). I was into electrical and electronic hobbies, and this book was great just to read what others had done. My father never let me build the X-ray machine because he was afraid I'd irradiate myself and get cancer.

    I'm happy somebody found it on the Web. But the book is far better.
  • I was hoping against hope that the article would be about something cool like integrating an X-Ray exposure over time from plain old sunlight, perhaps with a cooled ccd and nifty software. (That's what I've been thinking about doing with starlight for a year anyway..)

    Listen folks, you don't want to screw around with X-Rays unless you are heavily trained, okay? The lightest thing I can say is the article is irresponsible in light of modern technology and culture.

    My grandfather (God rest his soul) always wore bandaids around his fingers. They were always coming off or getting soggy and wearing out, his fingernails were a mess (I think he missed them on one or two fingers completely), and it looked pretty painful. You see he was a dentist, I guess around when the article was written. Unfortunately they didn't know that your body is a pretty good integrator of radiation too.. so it was standard operating procedure to hold the film in a patient's mouth while beaming the X-rays into it and spraying it around his own fingers at the same time. They didn't think, 'lead aprons are for wooses', they just didn't know. Seems dumb and tragic now.

    If you want to do something much more interesting than the proposed project, and maybe make a ton of money at the same time, why not work on integrating ambient radiation, whether sonic, electromagnetic, or nuclear. There was a good novel called Hollywood Dreamtime which talked about it a lot. The last thing we all need is for a young smart person excited by open source, hacking, and network effects, to start screwing around with unshielded spark coils. Odds are someone is going to get electrocuted or permanently damaged (maybe with malevolent intent).

    On a lighter note, you could also learn to build a fucking powerful microwave oven with an oil drum and similar parts. That's what the Om cultists did in Japan a couple years ago, to turn their victims into ash. I'd say that's safer than building X-Ray generators and maybe leaving them plugged in over night by mistake.. X-Rays are great and 100% natural but they are too energetic to fuck around with for a household hobby.
  • The /. editor made the off-hand comment that 'vacuum tubes weren't common'. And, that just ain't so.

    Want your CRT to give off lotsa X rays? Just crank up the High Voltage section. If instead of the 15KVA potential Mr. Electron is attracted to, there is a 45KVA potential, Mr. Electron would become VERY excited...and when Mr. Electron has to transfer energy, you will get more X-rays.

    The lead in CRT's help to limit the effect of CRT radiation....but the CRT can become an good xray source.

  • This is very, very old news (Score:3)

    by localroger ( 258128 ) on Sunday February 25, 2001 @04:35AM (#404977) Homepage
    I originally saw this project in a book of amateur science projects which was already quite old in the 70's when I was in high school. (I don't remember the title, but I think it might have been issued by Scientific American.) I actually did a few of the projects in this book, like the "mouse" that could learn to run a maze based on relay logic. The fact that the tube of choice was an 01A should tell you something.

    I do have a 01A and briefly considered building the X-ray machine, but fortunately came to my senses before trying it. The trend in professional X-ray machines has been toward lower and lower emission with more sensitive film and detectors. Long-term exposure to X-rays is quite dangerous even at low levels.

  • Aren't any nerds still playing their guitars through real amplifiers anymore?

    Your trusty Marshall probably needs some new tubes anyway...so there you are, 4 big honkin' 12AX7s and a couple of dinky little fellows.

    Just a thought...

  • The 12AX7 dual triode is not a "big honkin" tube. It is a 9-pin miniature base low power amplifier. The 01A is a single triode of much older manufacture, with the very old four-pin socket. It is about 4 inches long and almost completely opaque with silver getter, which is what makes it useful for the X-ray generator.

    And that's not even to get into transmitting tubes...

  • whelp (n.) 1. A young offspring of a mammal, such as a dog or wolf. 2.a. A child; a youth. b. An impudent young fellow. 3.a. A tooth of a sprocket wheel. b. Nautical. Any of the ridges on the barrel of a windlass or capstan.
  • What about us schmucks who have to sit in front of the monitor? They can't put lead in front of the screen.

    Why are these moles on my face getting bigger?
  • bathe in (reduced) radiation all day long.

    Much reduced. The radiation standard is so low that you get more exposure to X-Rays lying out in the back yard for an hour than you do in a lifetime in front of a computer monitor.

    People really underestimate the amount of environmental radiation. The Sun also bathes us in radiation all day long. A plane flight (above most of the shielding effects of the atmosphere) entails getting a pretty hefty dose of radiation.

    The main reason that there is lead in tubes these days is optical - heavily leaded glass has superior optical properties.

    TV's have vacuum tubes too, and because of the design changes that have been made over the years it turns out that some of the best tubes for making X-Rays are from TV's made in the 40's and 50's. Modern tubes can't be driven at high enough voltages to make significant quantities of X-Rays.


    MOVE 'ZIG'.
  • wrought, adj. 1. Put together; created. 2. Shaped by hammering with tools. Used chiefly of metals or metalwork. 3. Made delicately or elaborately. fraught, adj. 1. Filled with a specified element or elements; charged. 2. Fully provided. 3. Marked by distress; upsetting. the poster was clever, but gets very low marks for improper word usage.
  • but these go to eleven...
  • Folks:

    Many of the first experimenters with X-rays died due to the burns they received from the systems they built. X-rays are ionizing radiation (the worst sort of radiation hazard) and should be treated with tremendous care. Building your own X-ray machine is not a wise idea unless you are a medical physicist working on X-ray machine design.

    The shielding issues, the collimation issues, and every other issue you can imagine would be problematic enough. Making it safe would be quite difficult as well.

  • Look out! Radioacitve Man!

  • Re:Vaccum Tubes are *VERY* common yet. (Score:3)

    by Detritus ( 11846 ) on Sunday February 25, 2001 @05:48AM (#404987) Homepage
    When color TV was becoming popular, there was concern about x-ray emissions from the picture tubes, which operated at a higher voltage than that of monochrome picture tubes. There was even a home x-ray measurement kit, that consisted of a piece of photographic film in a plastic holder. You were supposed to attach it to the front of the picture tube. After a specified amount of time, you were supposed to remove it and mail it to the manufacturer for development and evaluation. There was and is a concern that the high voltage regulation in the TV could fail, allowing the voltage to increase to a level that would result in significant emission of x-rays.
  • What next, do it yourself appendectomies?

    Yes. That is project #15 in the "Suit YourSelf" home surgery kit.

    (Marketing thought "Suit YourSelf" was a better name than "suture self")

  • I see a Darwin Award coming out of this.
  • This was a great book. I picked it up for 50 cents when I was five -- the library was selling off a bunch of older books, and this was one of them. Never went so far as to actually build anything inside, mind, but it was like pr0n to me: how to build your own cloud chamber, or solid-fuel rocket, or grind your own mirror for a Newtonian reflector telescope. They even offered to send you a "radioactive speck" for use with the cloud chamber.

    Of course, it was a perfect match to the encyclopedias I grew up with: Our Wonderful World, published circa 1953, that had been my mother's when she was growing up. A wonderfully eclectic set, and filled with electronics projects that I was never able to get off the ground. Just imagine me in 1982 saying, "Dad, where can I get a 9X232H vacuum tube? I want to make this radio."

    Anyhow, glad to see that someone's put it up on the web; the book is much better, yes, but there can't be too many copies left in the libraries.

  • I had guessed this is where the web site came with out even checking. I have this exact book on my bookshelf now. It also has plans for building your own particle accelerator, with an "observation peephole" at the business end!

  • SCIENCE FAIR PROJECT???!!! (Score:4)

    by JoeGee ( 85189 ) on Sunday February 25, 2001 @06:21AM (#404992)

    "Johnny is sterile, but he got an A. We're proud of him, but of course we're sad about the grandkids."

    Lots of other readers have commented on the effects of x-rays, so I'll spare everyone the regurgitated diatribe. Just please be more conscientious in regards to the cutesy comments editors add when they post these stories.

    A better (if not safer) science project might be "The Darwinian Effect of Do-It-Yourself X-ray Kits on Budding Geniuses Who Spend too Much Time on Slashdot".

  • While I was reading the article on make your own X-Ray machine, I saw a banner ad that fit perfectly: Cluelessness: There are no stupid questions, but there are a lot of inquisitive idiots.
  • Except he was using highly radioactive chunks of something that crashed. He had a core dump, and it almost killed everyone on the planet, until he came up with some goop to put in the water, and cured everyone. There we go, lets have the government put some goop in our water after some idiot irradiates us all. Cool, that's a solution!
  • The magnetic tape would be fine. Why do you think people pass their laptops through the X-ray at the airport instead of the metal detector? The metal detector puts out enough of a magnetic field to nuke most drives, whereas an X-ray would only be harmful to EPROMS, if the exposure lasted, say, a few years.

    --
  • Actually, it was Fallout Boy that got his powers from x-ray radiation. Radioactive Man was exposed to an A-Bomb... :)
  • Yup. Could be a whole new category of Darwin awards too... Crazed scientist removes self from gene pool by irradiating his testicles with high-powered X-rays.
  • Cool! I wonder if you can double your intelligence by splitting all the atoms in your brain?! :-)

  • If you read to the bottom of the article, you will see that the copyright is 1960.
    I cant help but wonder about the safety of the experiment given the amount of knowledge about radiation that has been learned over the last 40 years.

    maru
  • Well.. If he'd also use an UPS, he could save them... -towo, thinking a UPS should be a standard household item.
  • Anybody know where one might procure some appropritate X-ray sensitive film to use with this device? Exposure?
  • If anyone gets something like this working, it'd be interesting to see some practical plans put up on the web!
  • .. or Ovaries. There are Female Geeks,

    at least that's the rumor...

  • Well it's a good thing I've got one of those lying around in my garage!

    I think this article was originally published in the 1950's. Model-T parts were a bit more common (though not much) back then. Now days you'd just substitute some sort of solid state switch driven by an oscillator circuit of some sort. It actually has quite a bit in common with the modern switching power supply in your computer, with the exception that the voltage is headed the other way.

    Funny thing... I looked at the drawing, and immediately recognized the model-T ignition parts in the pictures. There's one sitting in the basement of my grandmother's house. Just why my grandfather kept it is a secret he took to the grave. But if you really wanted to build one of these power supplies, and didn't want to engineer a solid state "vibrator", you might start by asking antique car enthusiasts.

    For the benefit of my concience... As a trained scientist that has worked with x-ray equipment, I strongly advise against attempting to construct this device. As they say, a little knowlege is a dangerous thing. This stuff requires more than a little knowlege to work with safely. You should note, that many of the scientists that did the early groundbreaking work in this field died horrible deaths at relativly young ages. It would be interesting to find out how Mr. Simons met his end, assuming he has.

    Temkin

  • Insofar as "old" tech books go - but I can go one better:

    There is a book, quite difficult to find now (in any condition - it is quite out-of-print), called "The Boy Electrician" by Alfred P. Morgan. This book was first published in 1913 (by Lothrop, Lee and Shepard Co.), and later again 1929, 1940, and 1948 (by the same publishers). A second printing was done in 1948, and third and forth in 1951, and 1952, respectively (my copy is the 1952 edition).

    A wonderful book, filled with all sorts of how-to and gadgets for the beginning 1900's geek. Delightfully illustrated by the author (from what I understand, the picture of the boys in the book were based off of the author's sons), most all of the projects were aimed at boys around the ages of 8-13, as far as I can assertain (although I may be completely wrong here - today I fear kids would be dumbstruck by the sheer amount of patience and volume of reading this book requires to build devices - I sometimes wonder if kids in those days were smarter). These projects ranged from magnets and static electricity, building batteries (using real lead and sulpheric acid!), building motors and generators, alarms, radios, telephones - and yes, an X-Ray machine.

    It seems that back in the day, one could easily purchase an X-Ray "tube" - a vaccumn tube designed to emit X-Rays - fairly cheaply (Morgan quotes 4 and a half dollars - which would equate to a bit of money today, but still fairly inexpensive). He then shows how to hook it up to a high voltage supply (which is built in earlier chapters using an ignition coil from a Model-T), then use a special "flourosope" to allow you to view the bones in you hand when you switch it on! It is funny in the naivete of the device, and how much damage could be done - but at the same time, such simplicity and curiosity is gone from our world, simply because of fear of danger.

    Alfred P. Morgan also wrote other books aimed at young experimenters - I know one was a more advanced book on radio and TV, and another may have been on chemistry (I have the titles of the books put away somewhere) - all of the books are difficult to find, sadly.

    Worldcom [worldcom.com] - Generation Duh!
    • Transuranics from common household checmicals
    • Asbestos for overclockers
    • Home hydrogen generation
    • Electrolysis of NaCl - disolve the byproducts in water
  • - Transuranics from household chemicals - Is this possible?
    - Asbestos for overclockers - Boring, Use BeO2 instead.
    - Home hydrogen generation. I'm not going to tell the secret of Red Devil Lye and Aluminun foil.
    - Elotrolysis of NaCl. It's hard to get the salt melted.
  • I'm happy somebody found it on the Web. But the book is far better. Yes. Some friends of mine built the Hilsch vortex tube from the chapter after the X-ray machine.

    Of more interest to Slashdot readers may be the "electronic mouse that learns from experience", a little wheeled robot with primitive AI built out of relays and stepping switches.

    I spent too much of my high school years building a computer out of parts like that. Sigh.

  • To those really interested in generating x-rays, you can find x-ray tubes and rectifiers on a regular basis on eBay. For the power supply, you can use one of those handheld electrocution devices, which nowadays can generate 100kV-400kV.

    Go to it. Before long, we'll have afforable Open Source Beowulf-powered CAT scan machines all over the place.
  • Depending on how powerful you try to make it.

    Once upon a time, shoe stores used to have X-ray machines with which one could look at their feet through it. Eventually these were banned, because they were supposed to be used only by licenced radiologists (and how many of those work at shoe stores?) and many were faulty, giving up to 100 times the recommended dosage!

    Some of you might find the idea of a shoe store having an X-ray machine as far fetched, but this is true! I know because my mother played with one a lot when she was a teenager, thinking it was good fun. According to her parents, there was a time where she used it almost every day on her way to public school in England.

    She died of cancer when I was five.

  • You can still get vacuum tubes fairly easily for under $10 (check out alt.guitar.amps). The article didn't seem to say what kind of tube you needed, so I assume most would work, I could be very wrong.

  • Any use of X-rays as a weapon would already be coverd by existing assault and battery, endangerment, or other laws.

    Of course that won't stop the legislators from passing stupid laws. Case in point is the "anti terrorism" laws passed after the OK city bombing. Last time I checked, it was already illegal to blow up a building and kill people.

  • step into the bathroom and fire it off while your unsuspecting in-laws remain in the living room....

    Naw, set it up in the guest bedroom and give them an 8 hour tan while they sleep.

  • RMS has been butting heads with Linux people for a long time. RMS is a FREE SOFTWARE enthusiast, and not a Linux enthusiast. RMS is actually pissed off that people call the whole system Linux, when its actually the kernel that's linux, and most of the other parts that make the system work (low level stuff like compilers and basic UNIX tools) are GNU utilities, which have been around a lot longer than Linus' kernel
  • Actually, the ionizing radiation damage thing is rather concerning- the project went through the stages of 'cool' to 'oi. NO!' in about 2s in my head (ignoring the limitations of finding magnesium getter valves in this day and age, which occupied about another 10s).

    Inadequate X-ray equipment seems to be a source of numerous nasties (those foot X-ray machines in British shoe stores, a cluster of leukaemia cases in Germany traced to an orthopaedic surgeon with a surprisingly miscalibrated machine from the 30s..) and adding more devices to the list of 'insidously dangerous experimental equipment that nobody except the builder knows how to operate in safety' is never such a hot idea...

    Additionally, I'd have to point out the obvious poor electrical design of the test setup- building projects that interface directly to the mains and involve sodding big inductors is not for little Johnny... which by no means increases my trust in the radiation safety advice of the book...

    Anybody have any information on spectral characteristics of X-ray sources vs. potential for cellular damage vs. sensitivity of film and discharge dosimetry? I always wonder if there's frequencies of radiation that the standard measurement setups don't catch.. I'd love to have an expert's opinion on this. Not that many would be lurking on Slashdot....

    Even more randomly, it would be interesting to see by how much the cancer death rates amongst medical personnel working in A&E environments involving emergecy X-ray work in the '50s to '70s exceed those of the general population. I suspect that they'll be higher in countries with shortages of medical staff at the time.. (dosimetry adherence in inverse proportion to dedication?)

    On a totally different note, what is the extreme (monetary) value of integrating ambient radiation, whether sonic, light, or ionising radiation? I can understand it's useful for environmental studies or astronomy (background radiation measurements in particular regions of sky) but how does it become a commerciallly valuable...

    Although the idea itself sounds intriguing when presented in such a throwaway comment- I'm missing the fascination here (what does total sonic/electromagnetic energy dose _tell_ you) and I'd like to know more... provided it has nothing to do with the insurance industry....

    And I can't find any references to the book either- suggestions where to look...

    Finally, to respond flippantly to your oil-drum cremation for crazed apocalyptic sect members comment- I'm sure the diameter of yer usual 55-gallon is a bit big for cavity resonance.... I'm also sure that's not what you meant.

  • Don't forget that the 12AX7's are triodes, and hence don't have the grounded shields of tetrodes and pentodes. Thus, their parasitic capacitance is wicked high, and prevents them from being used for high-frequency (ie, microwave and up) amplification.
    __ __ ____ _ ______
    \ V .V / _` (_-&#60_-&#60
    .\_/\_/\__,_/__/__/
  • I don't think you have it right. The article means traditional vacuum tubes - which are found in old radios and old TV's (pre-transistor electronics). They have not been common for a long time.

    They're not common, but they're not too hard to find either. Dozens of businesses cater to the antique/vintage-radio, musical-instrument, and "audiophile" (quite often "audiophoole" would be more appropriate) crowd that would have a use for tubes, either new-old-stock tubes that were last made 30-40 years ago (or even further back) or brand-new tubes produced today in Russia, China, and similar countries. Antique Electronic Supply [tubesandmore.com] is one that comes to mind. They usually have specials on slow-moving types that you can snarf up dirt-cheap. Hell, even Radio Shack [radioshack.com] can still get tubes on a special-order basis, though I suspect their prices run a bit higher for it.

    Keep in mind that the quoted article is over 40 years old, so its assumptions about what you're likely to find in the average household are more than likely dated somewhat. (I have a few old radios myself, and a small stash of tubes and related equipment...but I suspect I'm atypical in that regard. :-) )

  • Then by all mean, please do not build an x-ray machine. I certainly wasn't advocating that people go out and build one for party tricks. What most people do not realize is that it's not a trivial project. The x-ray machine described in this article is a "cold cathode" machine. It generates weak, soft x-rays. It's hardly very useful for weapons or "candid" photos (exposure times are very long).

    I've done a lot of research into this. I talked with two x-ray technicians and had a good, long conversation with a old x-ray repairman. The old x-ray guy finally convinced me that I would not be satisfied with a home-made model. It would create unimpressive radiographs and would require a lot of work.

    Modern x-ray machines use a "hot cathode" x-ray tube. They generate more penetrating, "hard" x-rays. They are also very bulky, 200 pound devices that require a lot of power. But if you want "real" radiographs with nice contrast and good depth then these are the way to go. I eventually bought two x-ray machines from eBay (Yay!) that I use for my own Polaroid radiographs. I won't go into the precautions I take (usually) while operating these machines. That is a left as an exercise for the reader.

    I haven't given up on building my own machine, but that's more for the challenge of building a really nice, small, High Voltage DC power supply. Maybe I will learn glass blowing and try to make my own hot cathode tubes.

    And, yes, I fully expect that my toys will take off about 10 years of my life. Such is the price of obsession. Now if you will excuse me, I must go apply some ointment to these oozing sores that I have mysteriously appeared on my face, neck, and arms.

    Yours, Noah

    P.S. The original article failed to note that I have my own Polaroid x-ray samples online. I am posting an update to the x-ray page [noah.org] to make these easier to find.
    http://www.noah.org/science/x-ray/index.html

  • A lot of tube amps use 12AX7 for the pre-amp section, 12AX7s are not big tubes. Marshalls mainly use EL-34 tubes for the power sections whereas Fenders use mainly 6L6 tubes. EL-34 and 6L6 are the larger tubes, I've got a 6L6 right here and it's about 12 cm long and about 4 cm diameter.

  • Yes, you can find x-ray equipment on eBay
    No, you cannot use a "handheld electrocution device".

    X-ray generation requires DC high voltage. Those stun guns and fake TENS devices produce AC electricty. Futhermore, the current on those those devices is quite low. You need a at least 10mA to drive an x-ray tube.

  • I find that iZone Polaroid film works well. You can buy it all Wallgreens and K-Mart. All film is sensitive to x-rays.
  • No, no, no... don't use those silly, old mechanical vibrators. You have to go solid state. Jeeze... Check out Bill Beaty's [amasci.com] page. http://www.amasci.com/ for some circuits. I had good luck with a 555 switching a 2N3055 power transistor to drive 16v through an auto ignition coil. I used a VW Beetle coil. Pretty simple circuit and cheap parts.
  • I hope you are being sarcastic. If not, seek professional help.

  • The Sun also bathes us in radiation all day long.

    Hey buddy, this is news for nerds. if you see the sun more than three times in a month, you have no business reading this website.

    Rich

  • I'd say use a 5Y3 GT rectifier or something like that if one was to build a project such as this, pretty big tube, common and since it's a diode tube it doesn't have all the stuff in it to melt down.
  • Remember, the original definition for a Roentgen (unit of radiation exposure) was that amount of x-rays that caused a visible reddening of the skin (erethema).
    The dose allowed to the workers that only work in the vicinity of nuclear facilities, by federal law, is 125 milliroentgen (0.125 roentgen).
    Most radiation exposure accidents in the last five decades deal with industrial x-ray machinery.

    An X-Ray machine is exceedingly easy to build, but very very difficult to run calibrated and collimated so it doesn't cause a problem to those in the general vicinity.

    It is just like it is very easy to make nitroglycerine. But, rather difficult to make it safely.

    MercTech
    Mercenary Radiation Protection Technologist
  • Mr. Science: Now, timmy, stand in front of this X-ray tube while I step behind this three foot thick steel plate!

    Timmy: Sure thing, Mr. Science!

    BWAAAAUUUGGGHHH!!!!

    Mr. Science: Uh-oh! We're gonna need another Timmy!!!

  • The "Boy Electrician" is very much back in print, available from Lindsay Books.

    http://www.lindsaybks.com

    It's their catalog number 21648, sells for $19.95 US.

    Lindsay's has a lot of great books available for sale that they reprint.

  • Yes. You would still need to have a rectifier in the system. These show up on eBay also, or you could use a series of high voltage solid state devices.

    There is no minimum current requirement for these devices, just tradeoffs in exposure times.
  • eBay comes through again. You can find x-ray film there too.
  • >Transuranics from household chemicals - Is this possible?

    Already been done [slashdot.org] and reported on /.

    The X-Ray project is very cool. But as others have pointed out, not something you want to build without proper training.

  • I used to have (possibly still have somewhere) an old book that described how to use an (off-the-shelf) X-ray tube with a fluoroscope you can make yourself - basically a thin layer of crystals that glow when hit by X-rays. So you look directly towards the X-ray tube, put e.g. your hand in the way, then the fluoroscope in front of your hand, and you can see the bones in your hand. It needs a much larger dose of X-rays than exposing a film, but that wasn't considered a problem at the time.

    http://www.uihealthcare.com/PatientsVisitors/Med Mu seum/CollectingFromPast/Devices/Devices.html
    shows a couple of fluoroscopes, and says the coating was "calcium tungstate which fluoresced more brightly than the traditional coating of barium platinocyanide". Neither of those sounds familiar, but I think it was something Health and Safety regulations would make it hard to get hold of for the home experimenter these days.

    One day I might get around to building the Whimshurst machine though.
    (http://www.netspace.net.au/~tphefley/ has some instructions that looks very similar, and may even be from the same book ("The Boy Electrician").
    --
  • Interesting case, isn't it: hide a "troll" (An annoying word in the first place, being a bastardization of "trawl.") under a gun control argument that's so PC even Slashdotters won't mark it a "Troll," then put in that usage error, as if to taunt us. Maybe the post was really a fiendish trap to re-ignite the troll/trawl debate. So I ask, half clever, or clever and a half?
  • Let see you build one, then we can have the government ban it. Wise guy
  • You can make you own flouroscope. Go on eBay and look for "x-ray film carrier" or trays. There are green and blue sensitized trays. These contain a sheet of plastic that is in contact with the film. When the x-rays hit the plastic sheet they cause it to glow which exposes the film. The x-rays alone would expose the film, but the florescent plastic enchances the image allows exposure times to be cut -- thus minimizing patient exposure to radiation. At any rate, there are two type -- green and blue. The green is brighter, the blue has better contrast. The plastic is embedded with rare-earth minerals (I think they use zink sulfide for green). You can remove the plastic from the film carriers and make your own floroscope... I'm working on making a digital video x-ray machine. Later on I'm going to try to make my own CAT scanner. I just need help with the software.
  • the beginning 1900's geek.

    The early twentieth century geek bit the head off chickens in a circus for a living. Later geeks displayed testicular irregularities and became eunichs. How these people became computer programers and engineers, I'll never know.

  • Ah, I forgot about them - and you are correct, they do reprint it. Still, nothing beats holding a hardbound edition from the original publishers (ok, I am a small-time bibliophile, so sue me)...

    Worldcom [worldcom.com] - Generation Duh!
  • Heh, heh - forgot about that meaning. Scary...

    Worldcom [worldcom.com] - Generation Duh!
  • Yeah! Great new material for Junkyard Wars!

    Build an X-ray machine out of an old EGA monitor. Or build a dye laser out of an old fluorescent tube and a package of Paa's Easter Egg color. Or build a pirate radio transmitter out of a microwave oven magnetron and a ballast transformer. Fun!

  • Quoting shambler snack:
    Is this another example of it doesn't matter (or even exist) unless it's on the web?

    You can't link to a book. Without a website this would never have been seen on slashdot.

    I for one am glad I learned about it. I will definitely be on the lookout for this book now.

  • Actually, that was "Mr. Lizard". But otherwise, a decent description of my favorite bits from the "Dinosaurs" sitcom series...


    --Fesh

  • Yes, zinc sulphide sounds familiar, and may well be what the recipe I had was using.
    (Hmm - aha, sulfide is the US spelling, not a typo like zink, and http://www.google.com/search?q=zinc+sulfide+fluoro scope gets rather more hits than sulphide. What is the Encyclopædia *Britannica* doing using US spelling? Oh well.)

    --
  • Sorry I couldn't find this science fiction book on the net either. I was referring to a technology brandnamed "Dreamtime" which in the book was a next-generation VR technology which allowed virtual scenes to be overlayed through glasses over a person's view. While used for theme parks, it turned out also to be wanted by quasi-military criminals, and the most powerful application of it was is incorporation into contact lenses.

    A bad guy ninja type in the book wears a powerful computer on his belt with a portable device like an ultrasonic sonar. By integrating the audio returns, this soldier was able to "see through walls", seeing an overlayed display on his field of vision. It would be the ultimate in wearable computing and vr.

    By commercial aspects I was referring to oil exploration, in which explosives generate a sonic wave through the ground and analysis of the returns lets you find pockets underground where there is oil. I worked with a company (musetech.com) which makes VR viewing and analysis software for this.

    Visible astronomy is also generally about integrating the amount of radiation to fall on a ccd chip as you probably know. There is one cool (literally) device I saw in a catalog which, by building up an image over time, lets you see faint images through your telescope eyepiece including for example a nebula's colors which the human eye can't generally make out.

    If you could do something similar with X-rays or sound waves it would be pretty neat I suppose.

    As for the cremation device, don't ask me I don't want to know these guys. I did however make a homepage that gained a little popularity at the time, which is still up at http://telebody.com/mattr/tero/

    This was a few years ago so I could be wrong, but I believe the Japanese media (I live in Tokyo) reported that the Aum cult was thought to have disposed of at least one body in an oil drum which had been turned into an exceedingly powerful microwave oven that could turn even bones into ash, leaving no evidence. The group's claim to fame was spreading Salin gas in the subways, when they weren't busy making LSD or drinking their guru's bathwater. They also were researching antipersonnel lasers and (I could have assigned this to the wrong people) I think they also shot a police chief near his home.

    Sorry I don't know their design but I just found a reference to the microwave oven here.
    http://www.cesnur.org/testi/aum_042.htm
    There are a lot of links if you look up Aum and microwave in google.com. But apparently they had a supergenius as their science and technology officer and (looking now at http://www.copi.com/articles/guyatt/aumi.html) probably could have made a big oven if they had to.. can't answer your cavitation size question myself.

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