X-ray machine

That looks like a great tube, all right. It picks up at 40 kVp, right where the one in the Faxitron leaves off. Do you know what machine(s) it was originally used in?

Also, any good PCB images with the Midmark?

-- john, KE5FX

Don't worry about it! The trolls and spammers waste more than you could use in 1000 lifetimes. :)

It is one the Hamamatsu general purpose Microfocus X-Ray sources:

and here is their full current line-up:

Those are very expensive -- I've been offered that exact L9181-02 with a 50% discount by their sales people, for "just $55K" -- but they are very good and de-facto standard. There are many other models (which are quite often the same units but just assigned different part numbers for using them in customer machines) but this lineup is their off-the-shelf general purpose ones sold as standalone units.

The last in lineup is L12161-07 which is their current (improved?) version of those L8121-01/03 units that I had two damaged ones. It looks exactly the same, just with different control box made for remote control only. The old one that I still have has full-featured control panel with all manual controls and displays and it can also be remote controlled so that new one is actually a downgrade. That last set is their crown jewel, most powerful of them all and going up to 150kV, higher than anything else. My current aquisition, L9181-02 is lower power (39W vs 75W) and only goes up to 130kV but it is very good unit nevertheless, second best of their general purpose sources. There are 50W units there but they have 15 micron minimal focal spot size while L9181-02 has 5 micron. And none of those go above 110kV.

The very similar one, L9181-05 is the same as L9181-02 but with wider beam angle (100 vs 45 degree) that is better for microscopy but not as good for general purpose use.

Almost all of those except the last two have all control electronics built-in so they don't need any external control box -- they are controlled with text commands over RS-232 port.

I would've happily exchanged my L9181-02 for a working 150kV L8121-01 unit in good condition, even without control box (as I already have one) but it is almost absolutely unlikely to find one so I'm very happy to have their second best :)

They are decent enough to find some soldering problems under BGA chips but not all that great. Then, that size 1 sensor is rather small so you can only catch some part of interest so it requires several shots to inspect the entire board. It is kinda useful for some other things though -- e.g. to find out what holds that @#$#@ plastic case after you seem to remove the last screw or discover what's inside some potted assembly or something like this but you won't see bonding wires unless you move the tube far away and make a maximum possible exposure and even then it would be not all that great.

BTW, I don't know what could be the use of anything below 30kV (maybe some soft tissues or something very transparent, low density?) Those low energy X-Rays are always filtered out on medical machines as they are useless for imaging while at the same time readily absorbed by the body thus increasing the radiation doze significantly. It is what they call "Aluminum equivalent" or so. Most of BGA chips are completely opaque at such low energies; you need something like at least 50kV to see through them.

However there is a use of low energy X rays but it is even lower than 30kV. Hamamatsu make what they call PhotoIonizer units that are used as electrostatic removers:

Those run at something like 9.5kV and are of very low power. I have a couple of their L9873 units that are like that L12645 but have all control electronics built-in and don't require an external control box. Those are really nice and they do work. And as it is X rays they are effective at relatively long distances unlike e.g. "Nuclespots" which use alpha radiation so they are very short range. And unlike Nuclespots they don't have any decay with time (VERY SHORT time for nuscespot as it is Po210 source) so they last forever. On the other hand nuclespots don't require external power supply but that is a questionable advantage...

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Don't some x-ray machines use a silicon array for the imager? And aren't they more sensitive requiring less exposure time? Can't be too hard with all of those 'phones around for homebrew prototype.

Yeah, I can't see wanting more than 130 kVp. I wonder if that would be enough to start damaging parts. Not sure where the limits are.

This machine was used for bone density studies on rodents at a big pharma company. It came with documentation showing annual service by the Faxitron tech, right up to the point where they lost the password to the PC. I don't think they used it much, certainly not after that. Wish I knew how many hours were on the tube.

Obviously there were no HIPAA concerns, but they still didn't sell the PC with it. :(

Fortunately that's not the case. Some favorites:

(XEM3005 FPGA board with Spartan3E and Cypress FX2LP, 3x mag IIRC)

(MCP23018 I2C extender QFN, standing on edge)

LT8650S buck regulator, 5x mag. Package size is 6 mm x 4 mm.

BeagleBone Black, 1x mag

Closeup of SoC on BeagleBone, 5x mag

Note that these required exposures up to 30 seconds. If the machine were limited to typical dental exposure durations, it wouldn't be very useful.

-- john, KE5FX

A lot lower than 130kV. I once used a lot of one-time programmable microcontrollers (Hitachi 63P01) and wondered whether I could erase them with X-rays. I had access to a small microfocal X-ray machine, so I experimented. The result was disappointing. I used the lowest energy I could, which was probably 30kV or 35kV. I exposed a quartz window CMOS eprom for initial testing as this was more convenient - I could read back the contents at regular intervals during breaks in the exposure. After something like 10 minutes exposure at a range of maybe 10cm from the target the eprom was erased. I was able to reprogram it and it verified correctly, but only for a short time. Unfortunately, it discharged within minutes, so there was permanent damage. I didn't try things like annealing it which I only thought of much later. In any case, if even short-term damage was being caused by an exposure only just sufficient to erase the eprom then this was clearly not going to be a sensible way of treating devices that would be used in a critical application. John

It is nice to have and it doesn't damage anything. Also it has almost twice the power (Large Spot only -- they have same limit with small spot) that might be useful at times for either reducing exposure time or being able to see through at all.

Eh, they almost never do and those Faxitrons sold with PCs (I saw a couple on Ebay) had ridiculously high asking prices.

It is all rather significantly above 30kV. And long exposure times. For PCB inspection you need real-time video and moving object fixture that allows to move and rotate the inspected object. This allows to do optical zooming and do everything in real time. You turn the voltage knob and see in real time how different parts become transparent. You move the object between the tube and sensor and magnification changes in real time so you can look at whatever part you need at the angle and magnification you need and you can chose optimal voltage/current so you can see what you want to see. It is not like higher is always better -- any material has it's range when it is opaque, totally transparent (i.e. disappearing from the picture) and anything in between.

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True, but my point is, you don't need 50 kV. You'd *like* 50 kV+, given the option, but 35 is much better than nothing.

This thing goes down to 15 kV if I remember correctly, but I've never seen an application for that. Occasionally when shooting through plastic or something similarly transparent I can get better contrast by going down to 25 kV or so, but the difference isn't dramatic. I overclocked it to 37, and that's usually where I run it.

Yep, all very true. This is the kind of thing you want near your workbench, not on the factory floor. On a production line a low-voltage cabinet machine wouldn't be ideal.

BGA inspection in particular is a lot more involved than just shooting X-rays at the board and calling it good or bad. JL has some nifty optical toys for that job already.

-- john, KE5FX

Interesting. How would you anneal it? Heat and/or high voltage?

I haven't tried erasing EPROMs with mine, but it does make sense that a 10-minute exposure to X rays in the PHz rangee would be comparable to a much longer exposure (days?) to UV in the EHz range. I've definitely ruined EPROMs with excessive UV erase time.

I should try nuking a 24LC64 or something and see how that goes.

-- john, KE5FX

Early eproms, before quartz windows, were intended to be erased by xrays. Something like three times max.

--

John Larkin         Highland Technology, Inc 

lunatic fringe electronics

I was thinking that maybe baking it would help it recover. It would be interesting to see what results you get. I no longer have easy access to X-ray sources. My idea was that there might be a market for a cheap X-ray eprom / microcontroller eraser because at the time plastic packaged one-time programmable parts were much less expensive than those with quartz windows. As soon as I discovered that the part I tested was damaged I gave up on the idea. Later, eeprom and flash memory made the whole idea irrelevant. However, it is still interesting to understand more about what actually happens during irradiation.

John

On Sunday, October 13, 2019 at 3:09:49 PM UTC-7, >

I guess the surprising part is that they weren't erased immediately in JohnW's experiment. They remained readable up until they didn't, at which point they were damaged.

Must be a matter of fewer photons per unit area. Less probability of an ionizing collision that drains a trapped charge, but more dramatic effects when it happens.

I appear to have swapped my petas with my exas...

-- john, KE5FX

• Shows about 4 trace errors on the left...

You may be up to a disappointment there.

I tried to erase plastic-cased EPROM 8052's years ago. We started with different X-ray machines and ended up with a cancer treatment accelerator, with no result. The chips still checked with the original code and worked fine.

--

-TV

It wasn't quite like that. The erasure was somewhat progressive, just like with UV erasure. For a while nothing changed, then more and more bits changed state until they were all done. What was surprising was the behaviour when I tried to reprogram the device. The programmer verified each block just after programming. These verifications were all fine. Then, it did a final check of the whole device all in one go at the end. It was this that failed, so the charge had leaked away from some of the storage cells that were programmed early on in just a few minutes as the programmer worked its way through the device. The devices were definitely CMOS and were probably 27C32. Most likely made by Hitachi as I would have wanted something comparable with the Hitachi microcontrollers that I was using. John

Nice pix.

This is funny: we license a laser controller design to a big semi equipment company, and they have it built by a contract manufacturer. One RF NPN went EOL so they bought a reel, a lifetime supply, but had that managed by an EOL consulting company. They x-rayed some transistors

and rejected them all for "saggy wire bonds."

--

John Larkin         Highland Technology, Inc 

lunatic fringe electronics

BTW, here is something that looks like a decent setup:

However, that L7902 is built for a machine (i.e. it is not a general purpose source) so there is no information about it on Hamamatsu website. It might be worth asking their support about it but I don't know if they would be willing to help with that one. It also requires an external controller and it is not clear which one as there is no even sales brochure available. Another unknown is that Thales Image Intensifier -- the Thales Group is a French company deep into military/aerospace so you have to get an online account with them just to ask questions and that is not something easy to get -- you have to APPLY for account and they MIGHT give you one. I was not able to get one.

Thales TH 9464 QX is listed on their site and their scarce datasheet says it is 6" device with "Very high resolution" which is 70 lp/cm according to that few data available as regular (?) one, non-QX supposedly has something like

48 lp/cm but that is not all that certain.

The best bet for Image Intensifier would be something Toshiba E5877J based which is 4" device with actually high resolution (77 lp/cm full 4" and 110 lp/cm in 2X zoom mode that takes central 2") There is datasheet available that is sufficient to make it work (it only requires 24VDC with a single wire switching between normal (open) and zoom (shorted to ground) mode that is very easy fo figure out. Those were also sold by North American Imaging as AI5877JP. That is what I have.

Those big ones (9" and bigger) from different X-Ray medical machines might be tempting but they all have much lower resolution, they are very big so they have to be shipped Freight, and there is usually absolutely no documentation available from anywhere so it is unknown how to hook them up.

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