Homemade Xray Machine

Hello!

I'd like to Show you my latest project, a homemade xray machine.

But before I start I have to point out, that xrays are really dangerous! To protect my enviroment, I use plenty of lead. So if you handle with xrays be careful and protect everyone...

Some interesting links:

• http://www.idc-online.com/technical_references/pdfs/electronic_engineering/Rectifier_X_Ray_Machine.pdf

• http://4hv.org/e107_plugins/forum/forum_viewtopic.php?73439

• http://4hv.org/e107_plugins/forum/forum_viewtopic.php?106277

Step 1: High Voltage Power Supply

To produce xrays using a simple vacuum rectifier tube you'll need a high voltage power supply. I use the popular ZVS-circuit, an AC-flyback transformer and a cascade, to increase the Output-voltage up to 50-60 kV. For the cascade I took 10nF/20kV capacitors and 20kV/5mA diodes. You'll also need a powerful transformer (f.e. a 12V/250VA like mine).

Step 2: The Xray Tube

You can use several vacuum tubes for producing xrays. In my case I use 2x2a recitier. Of cource you can take real xray tubes f.e. from a dentist too. They are offered on ebay for less than 80 USD.

Step 3: The Housing

To protect everyone from the xrays you have to put the vacuum tube in a safe housing. My housing is made of Wood with 3 layers of lead at the outside. Only through a small window covered with thin aluminum foil the xrays can go out.

Step 4: The Photographic Xray Film

To see the xrays you'll need a xray box. Inside there is a xray sensitive foil, which converts the xrays into visible light (f.e. green light). This foil is placed behind the object you want to shine through.

Step 5: The Whole Setup and the First Test

As you can see in the circuit, the xray tube is connected to the high voltage. To Limit the current, there should be a 2.2 MOhm resistor (10 W/40kV-type). The Output voltage is being measured with an ammeter and a 1 GOhm resistor. Therefore 1 µA corresponds to 1 kV. The current through the vacuum tube can be read from a 5mA ammeter.

To get the pictures a camera is located behind the xray-foil. I use the 10s-self-timer and 30" exposure. In the mean time I run out of the room and switch on the power with my remote control. Within the 30 seconds I switch on and off 3-4 times to prevent overheating of the vacuum tube and arcs.

Step 6: The Results

Maybe you want to take a look at my YouTube-channel: https://www.youtube.com/user/stopperl16/videos

more physics projects: https://stoppi-homemade-physics.de/

Thank's for watching and stay curious ;-)

Comments

[Kiteman]

It would be nice to see some data on the dosages received by users and passers-by...

[AirbourneNation]

He said he uses plenty of lead, which is good for stopping/dampening radioactivity.

[Kiteman]

Define "plenty".

Depending on the exact energy of the X-rays, the bare minimum thickness of the lead required varies by a factor of around 200.

Let's be clear here, I am not against the hobbyist building X-ray machines, but they really need to know what they are doing, and if they are going to share what they are doing then it's kind of important that they help their readers to not make their neighbourhood glow in the dark.

[stoppi71]

Hi Kiteman!

I totally unterstand your point of view. I've taken a look at the absorption coefficient of lead. You're right, that this value changes from 10² cm²/g for 10 keV to 0.1 cm²/g for 1 MeV energies. I suppose an energy of 50 keV, which means a value of 5 cm²/g. With the density of lead (11.3 g/cm³) you get an extinction-coefficient µ = 56 cm^-1.

For 50 keV x-rays the formula for the intensity is: I = I0 * e^-(56 * x [in cm])

So a thickness of 3 mm reduces the intensity to just 4.4 * 10^-6 percent! I use 6 mm lead just around the tube housing. Therefore the absorption is around 1.94 * 10^-13 percent. In front of the housing there are additional lead-plates (3 mm thickness) to avoid any danger or risk ;-)

[Kiteman]

But how energetic are your X-rays? You don't specify an energy or a particular tube.

[stoppi71]

Hi once again!

As I wrote I suppose an energy of about 50 keV. The output voltage of my multiplier should be in that region (flyback 5 kV + 10x Multiplier).

[Kiteman]

As you said, suppose. The energy of the X-rays depends also on the nature of the anode, and if your readers don't buy the same anode as you used, how will they know what they are producing?

[stoppi71]

The shortest wavelength of the xrays only depends on the voltage. And when you accellerate the electrons with 50 kV, the produced xrays won't get over 50 keV. The characteristic xray-lines aren't important for the highest possible energy. Therefore the Material of the Anode isn't really important, as long as the thickness of the lead is calculated for the maximum of the energy.

[stoppi71]

And for the lower energetic characteristic lines the absorbance coefficient will be higher too. So their increased intensity will be compensated by the higher absorbance.

[AirbourneNation]

200 what?

[Kiteman]

A factor of 200.

Two hundred times.

If you can't do such basic maths, you're never going to be safe trying projects like this.

[AirbourneNation]

I meant measurement units, like meters and such.

[advanced.sniping18]

is this safe to use on a human body? not trying to wait 6 hours in a hospital for a nurse to tell me the bone is broken or not and probably not for a one time use because ive been braking my bones alot lately dirtbiking

[doktordoris]

of course it is ! utterly harmless. as you no doubt know ionising-radiation is famed for being harmless. just ask Mme Curie!

[doktordoris]

"To protect my enviroment, I use plenty of lead" - now that's a sentence one doesn't often read!

[gurlz1234567]

How we can find voltage, resistor in xray tube? Can you send me formula?

[kirilt650i2]

Are the ammeters DC?

[stoppi71]

Hi! Yes, they are. You get DC from the output of the multiplier...

[kirilt650i2]

Thanks.
I have another question. What type of 1GOhm resistor do you use?

[stoppi71]

I use two 500 MOhms/20kV high voltage resistors in series like these: https://www.ebay.com/itm/Hochspannungswiderstand-20kV-470-MegaOhm-high-voltage-resistor/281026497195?hash=item416e7c0aab:g:LykAAOSwDN1USHg~