X-Ray machines - Technology and use in Hobby Electronics.

[Fraser]

Regarding damage to flash memory caused by X-Ray exposure, I have just read a post by 'Psi' on the topic. From what he says it appears unlikely that damage will occur to flash memory with normal exposure to airport type X-Ray units etc.

 https://www.eevblog.com/forum/chat/x-ray-machine-resources/msg57212/#msg57212

Aurora

[mikeselectricstuff]

Sadly no one does anything for nothing in the UK these days....they would just send you the fat bill and pursue you for its payment to the grave 

..which is why we have so much fly-tipping.

[German_EE]

In decades of electrical engineering (plus some electronics on the side) I have only once needed something x-raying. In this case I just went to the local vet with a six-pack of his favorite beer, a man who had the right equipment and the knowledge of how to use it.

[SeanB]

In decades of electrical engineering (plus some electronics on the side) I have only once needed something x-raying. In this case I just went to the local vet with a six-pack of his favorite beer, a man who had the right equipment and the knowledge of how to use it.

And I would bet he was happy, as there was no sharp teeth attached to the one end looking for his arm when he stuck a thermometer in.

Like the guy with a sheepdog, who had just bitten him, so he had a dog biscuit out so he would know which end to boot.

[HighVoltage]

What a great topic.
I wish also to have an x-ray machine in my lab.

Every time I need something X-Rayed, I go to my dentist.
Here is a picture attached of a high voltage connector, embedded in a hard epoxy resin potting.

This was done a modern digital X-Ray machine at a dental office here in Germany.
The X-Ray machine is made by Sirona

[timb]

I just hide the circuit in my mouth when I go to the dentist. It's like a 2-for-1! Unfortunately I had to get a Wisdom Cap pulled last time.

If it's too big to fit in my mouth I just make my dog eat it and it's off to the vet!


Sent from my Tablet

[Precipice]

I bought a pair at around GBP50 each as they will become unobtainium once the sellers stock is exhausted. They are far easier to use than a conventional high voltage tube and have better output than an old TV EHT rectifier valve. I may sell my BS7-W's if anyone wants them as my Faxitron will serve my needs fine.

I'd certainly be interested in those tubes! (at the moment, all I've got is a 6VS-1, and these look a lot more convenient).

[ovnr]

Incidentally, I've got a Trixell Pixium 4700 5-megapixel FPD sitting here. It does 2480 x 1910 at up to 7.5 fps with 154µm pixels.
I was somewhat surprised by the fact that it only has optical interfaces - four slow ones (RX/TX/sync) and a ~1gbps high-speed data link. The only other connector is a DB9 for power; it takes 24V @ 5A, and is liquid cooled.

If any of you nutcases want it, make me an offer.
(It was pulled from working equipment - I should do a writeup of my teardown of that.)

[MadTux]

It's all about having a diode array xray detector or any other reasonably sensitive digital xray detector. You can work with small beam currents and still get beautiful pictures, 300uA @ 35kV =>12W beam power, lol.
Small beam current also produces a small focal spot and therby sharp images, since you only need a small filament and get no overheated/melted spot on anode.

A while ago, I also played around with a experimental xray setup, but quickly decided that I better stop until I get good lead shielding, since my old polish DP-66 geiger counter clicked madly from backscatter.
The tube was behind more than 5cm of lead blocks, so no direct xray hit me, only the backscatter from the wall. Unfortunately I somehow got really bad xray intensifying screens that failed to glow even when directly in front of the tube. A movie camera that was placed in front of it showed "snow storm" as the HV was switched on. ZnS doped glow in the dark plastics also glowed quite nicely.

HV supply consisted of a HP 6274 PSU that was connected to a Mazzilli driver on a homemade flyback transformer. Output went into a Cockcroft–Walton multiplier that finally generated around 100kV DC at a few mA max.

Does anyone btw know a document scanner that only needs small amounts of light? I thought about converting normal scanners into xray detectors by placing an intensifying screen on top of it and disconnecting the power of the LEDs or CCFD that usually iluminate the document. In theory this setup should have much better light collecting capabilities and is much smaller than the long exposure DSLR setups that are usually used. Furthermore there's no barrel distortion caused by uneven distance from camera lens that has to be corrected in GIMP. Xray noise could be eliminated by running multiple scans and ANDing the reults.

The Canon N670 (cheap crap scanner) that I tested for that purpose had really bad ISO sensitivity (tested by placing multiple layers of newspaper between scanner and flashlight), so bad that I doubt it could pick up any light from a intensifying screen.

[Fraser]

As has been stated, an X-Ray machine is not an essential in the modern electronics lab but it is nice to have the capability and I am a self confessed imaging technology geek !

My MX-20 likely cannot inspect BGA balls as its only a baby in terms of KeV. I will do some images of chips to see what it can cope with.

I have used X-Ray for non destructive testing and investigations into electronics buried within potting. It helps to know where the components are located. I have used X-Ray recently to identify the components used in my very rare and expensive HP LogicDart logic analysers.

I was a regular user of X-Ray equipment so for me it is little different to owning a microscope or thermal camera..... Right tool for the job, that's is my MO.

What do you do when you can't tear it apart?....... X-Ray it !

Aurora

[Fraser]

@Precipice,

I have two brand new BS7-W tubes. You can still buy them from Ukraine but Customs charge TAX & VAT. I will contact you via PM to discuss a mutually acceptable price I am happy to break even on the non Tax eBay price or even take a bit of a loss as I am unlikely to use these lovely little tubes.

Aurora

[Fraser]

I was asked by several people reading this thread about selling my two new BS7-W 15KV X-Ray tubes. I no longer need them as I have the Faxitron units. The original sale of these stalled so anyone who still wants them, please PM me and I will see if we can do business. To remind those interested, these are small heated cathode X-Ray tubes with an axial X-Ray output and tungsten target, from the MYR-2/4 system. They produce a controlled beam of X-Ray when 15KV is applied to them. Beam divergence is specified as 5 degrees and they may be run in continuous mode (not pulsed like some) from a common CCFL HV inverter with additional voltage multiplier stage for 15KV output. I am still tempted to keep them as they would make a decent controllable X-Ray test source or X-Ray microscope (which is what they were designed for). I would like to see them used rather than them sit in my spares boxes though.

These are far more refined than using (abusing) a diode valve and the beam is controlled rather than a spray of X-Ray that occurs around a diode valve.

Aurora

[Fraser]

Tubes have now found a new deserving home. Apparently they are very special tubes that are perfect for X-Ray crystallography.

Aurora

[Fraser]

For those wondering what an X-Ray machine is used for in the electronics production industry, PACE manufacture the XR3000 inspection system. I was surprised to see that it uses only a 50kV tube to do its work. Lead is a significant attenuator of X-Ray yet a 50kV tube is obviously enough to see inside BGA solder balls.

Manual is here:

http://diagramasde.com/diagramas/otros/XR3000_En.pdf

http://competence.com.mx/prods/pace/html/_ShowSystemDetails-5121.html

It costs $57000 

My Faxitron MX-20 is fitted with a higher specification (smaller spot size) 50kV tube  and a more sophisticated imaging array 

Having briefly looked at BGA chip solder balls, I can certainly see their shape and alignment, possibly even voids within them.

I am fortunate enough to have been gifted another, more powerful, X-Ray machine. Its an 80kVp cabinet X-Ray unit with digital imaging. It will be delivered after Christmas so I will hopefully have enough power in that unit if the Faxitron can't cope with solder balls.

If people in the UK need something X-Ray imaged I may be able to help. Watch this space.

Aurora

[Fraser]

Mike has bought a Faxitron now 

He has done a teardown and created a thread here:

https://www.eevblog.com/forum/reviews/faxitron-mx-20-x-ray-system-teardown/msg585230/#msg585230

Aurora

[Sal Ammoniac]

My MX-20 likely cannot inspect BGA balls as its only a baby in terms of KeV. I will do some images of chips to see what it can cope with.

I know nothing about X-Ray machines, so I'm probably wrong on this, but can't you just increase the exposure time penetrate the chip, or is the penetration capability of a machine solely due to the energy of the X-RAYs?

[Fraser]

X-Rays have photon velocities energies proportional to the tube acceleration voltage (kVp). The higher the velocities energies, the higher the penetration through dense materials. As a material becomes thicker or more dense it attenuates the beam that illuminates it. If no photons make it through the material, no image will be possible. the current drive in the tube does not influence the penetration distance through a material.

In a classic case it may be found that 50 kVp will not produce an image through 3mm of aluminium plate but 120kVp will. In the case of high resolution imaging it is important to use the lowest possible kVp that achieves correct exposure as definition suffers as the acceleration voltage increases.

It has been asked whether the 35kVp of the Faxitron may be exceeded through modification. The answer is not simple. The Faxitron MX-20 uses a 12 Watt tube rated at 50kVp max and 1mA max. It is air cooled in the MX-20 rather than in an oil bath. The variable output DC power supply has a range of 10kVp to 35kVp so that would need to be changed. It is feasible to increase the tube drive but then cabinet containment becomes a concern as the kVp (and so penetration) increases.

Aurora

[mikeselectricstuff]

My MX-20 likely cannot inspect BGA balls as its only a baby in terms of KeV. I will do some images of chips to see what it can cope with.

I know nothing about X-Ray machines, so I'm probably wrong on this, but can't you just increase the exposure time penetrate the chip, or is the penetration capability of a machine solely due to the energy of the X-RAYs?

Not really - increasing exposure time gives you better signal to noise on rays that penetrate at least a little, hence you can just about get images through copper foil on PCBs, but 35kV just won't go through any serious distance of metal. I don't know the physics but I'd expect there are some exponential functions involved.
 

[mikeselectricstuff]

An analogy is that if you compare x-rays to light, current is like brightness, and kVp like colour temperature. 
The output contains a range of wavelengths up to a limit determined by the kvp, the lower end being determined by tube material and other filtering ( aluminium is often used to filter out softer, longer wavelengths).

Think of metal as a blue filter - light from even a really bright red-hot filament is not going to be visible though it, but a dim white-hot one will make it through easily

[Fraser]

Some useful reading on the penetration of X-Rays may be found here:

http://www.sprawls.org/ppmi2/RADPEN/

[Sal Ammoniac]

X-Rays have photon velocities proportional to the tube acceleration voltage (kVp). The higher the velocity, the higher the penetration through dense materials.

Really? I though that all photons have the same velocity, namely C. Perhaps you mean photon energies?

[Fraser]

Ooooops. Energies is the correct term as you say.

Aurora

[mete]

Hello everyone. I'm new here. Your topic is interesting. My question may be a little different then the title you are currently discussing. I plan to make an x-ray spectrometer as hobby. Penetration isn't necessary nor important. I wonder what would be the minimum usable energy to stimulate the atoms on the substance surface? Should the applied energy vary according to the properties of the analysed substance (i.e, atomic weight)?

[Fraser]

http://citizenscientistsleague.com/2012/12/28/alpha-particle-x-ray-spectroscopy-x-ray-fluorescence-in-the-home-lab-or-fun-with-quantum-physics/

XRF can be carried out with nothing more than the sources out of ionisation smoke detectors. You can also buy miniature pyroelectric X-Ray generators for XRF but they will be hard to find and expensive. Datasheet attached.

The other X-Ray source worthy of consideration is the Russian BS7 W transmission type X-Ray tube. A very 'cute' tube that produces a 5 Degree beam width of just the right power for Crystalography and XRF as that is what it was designed for. It requires a 1.5V heater supply and a 12-15kV EHT at very low current. Sadly the source I bought from has sold all stock and I sold my two units ages ago. A colleague of mine did buy several and if you get really stuck I could always ask if he wants to sell one.

http://www.hardhack.org.au/xraydtt

http://www.hardhack.org.au/crystallography

IIRC they cost around $60 each

http://www.sovtube.com/x-ray-and-geiger-tubes/317-bs7-w.html

Aurora

[mete]

These ones are very useful information for me. Thank you for your response at speed of light