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Fireside Chat with the Xperts: Stump the Chumps Round Three

The answer is “photons don’t care.”  The question comes from one of the many in out backlog of viewer questions from our earlier Fireside Chats with the Xperts.  Drs. Glen Thomas and Bill Cardoso are back for round three, working through a few more these and offering their masterclass in X-ray technology along the way.

This presentation discusses a question about significance of beam direction in X-ray system configuration.  Of course the answer is much more involved that suggested above, and offers further insight into the many considerations involved in designing an X-ray system.  The doctors then enjoy reflecting on a question about interesting things they’ve imaged over the years.  History buffs will especially enjoy Dr. Cardoso’s story of X-ray inspection of dog tags.  You can see many interesting images we’ve collected in this gallery.  Register for upcoming Fireside Chats with the Xperts and view our archives here.

Transcript:

David Kruidhof:

Welcome to another Stump the Chumps, here at Creative Electron. Again, we have Dr. Bill Cardoso and Dr. Glen Thomas with us to answer some questions that we’ve been accruing over the period of time that we’ve been doing these fireside chats. So, let’s go ahead and dive right in. We like to spend awhile on these questions, so I don’t want to waste any time with witty banter.

Dr. Bill Cardoso:

But typically get more than one or two today, right? David?

David Kruidhof:

Yeah.

Dr. Bill Cardoso:

You have to get faster asking the questions. That’s your fault. You know that, right?

David Kruidhof:

Yeah. I just got to start interrupting you in the middle of it.

Dr. Bill Cardoso:

Yeah, you’re just too slow, that’s the problem.

David Kruidhof:

All right. So the first one is, why do different systems employ different beam direction? For example, horizontal top to bottom, bottom to top.

Dr. Glen Thomas:

That’s an interesting question. And actually a good question, typically in an X-ray system, right, we really start out with the sample and what we’re trying to accomplish, right? So we have a few criteria. We need to be able to see the defect or see the artifact or see the landmark, what we’re trying to accomplish. We need to look at magnification, how much magnification do we need in a system. The sample, what type of sample are we looking at? Again, that goes back to what are we trying to see in the image? And from that point, we can now determine what configuration that we would need. Like we’ve covered in the past, essentially, we’re taking an X- ray source. In our case, it’s a electromechanical, it’s an X-ray tube. We’re applying some voltage to it, getting some photons out the window, shattering those photons towards the detector.

Dr. Glen Thomas:

It could be a flat panel detector. It could be an image intensifier, could be a line scan camera again. It all depends on the sample and what we’re trying to accomplish with that sample. In this case, we would take a look at the X-ray source and decide, resolution wise, so a larger focal spot would require a longer source to image distance. The X-ray beam is a point source essentially, and it comes out in a cone angle. That cone angle has some geometrical unsharpness, and we have some convergence of beam in that cone angle. So we need to determine what the source to image distance would be ideal for the application, right, so we may be able to use an 80kV 33 micron source. We may be able to use a one micron source, right? It depends on the application again. The closer the focal spot is to the window, the higher the magnification, and the closer we can get that source to image distance. The number effect and the geometrical unsharpness affect will affect the X-ray image, so if we get a very tall sample, we would want to have a very large source to image distance to increase that beam size, increase the sweet spot in the beam. There’s quite a bit of physics involved.

Dr. Glen Thomas:

As far as top to bottom, on an X-ray system left to right, it doesn’t really matter. Again, it depends on what you’re trying to accomplish. It makes no sense to have a long source to image distance, and then put the sample right on the detector or have a long source to image distance, and then have the sample up in the air. There’s a compromise on both sides. Photons don’t care if it’s top or bottom, left or right. You’re shooting photons through the sample, casting an invisible image on the detector and getting a result in image. Regardless of the image detector, that’s how it has to happen. That’s why it’s transmission X-ray. So it all basically comes down to the sample, and what we’re trying to accomplish with the sample. Electronic components, we want more magnification, a natural magnification, geometrical magnification, and we get that by putting the X-ray source on the bottom, putting the sample closer to the X-ray source.

Dr. Glen Thomas:

If I wanted more magnification, I would flip that around, or if I wanted more field of view, I would flip that around and put the sample closer to the detector. That will give me a larger field of view, but less magnification. So again, that would be a compromise that we would have to determine what’s a good working area, what’s a good size for the field of view because if you remember, we’re taking an X-ray source and the detector with a distance of 36 inches, 18 inches, whatever. If we put the detector… So we have 18 inches. We put the sample in the middle of that 18 inches. We will get two times magnification with geometrical magnification, right? So with that, if you follow the cone of the beam, we will get a reduced field of view. So we may have a four-inch detector, but we will get roughly a two inch, one and three quarter inch field of view out of that. And as we get closer to the tube, that field of view will become smaller and smaller. So it’s a compromise between field of view, magnification resolution and detector size as whether we would go on the top of the tube top down or bottom up.

Dr. Glen Thomas:

Horizontal X Ray systems are ideal for hard, heavy cumbersome parts. Same concept is vertical. We just put the X-ray tube on, say the left, the detector on the right, and we put a stage in the center that we can set the sample on. And typically you would fixture the sample to a degree, but you would use gravity to hold the sample onto the stage. Suspending a sample out in the vertical system that say weighs two or three pounds becomes more cumbersome, and that creates a lot of issues, a lot of problems in breaking X-ray tubes and detectors when you drop that sample in the system, and in some cases like say an engine block, the ideal method would not be left/right, up or down. It would be a C arm type configuration, where you have the X-ray tube and the detector on a mobile arm, and that mobile arm would move around the sample and do this stage. So that’s, that’s another version of the same thing, but as far as top/down or bottom/up, makes no difference as far as the photons are concerned. It’s really the manufacturer understanding the physics of X-ray and applying those physics to get the best result and image.

Dr. Glen Thomas:

Anything to add?

Dr. Bill Cardoso:

Yeah, it’s interesting that, as you were describing the different configurations, I was thinking historically, right, how many, even for electronics, how many variations were there in the 80s and maybe early 90s, and then by the late 90s, early 2000s, we’ve seen a convergence, right, of the configurations. For example, do you remember people used to put the X-ray source for electronics, right, where you have… Electronics, you’re usually expecting flat things, right, PCB, right, printed circuit boards. So it’s a flat sample, XY, that you want to be able to move an XY. So it’s very intuitive to put that on a stage, right, a low density to stage, carbon fiber or acrylic or any type of a stage that allows you to move the sample in XY. You have that sensor and the source and the vertical beam, so that you can easily move the sample. You would get exactly the same image if you flip it around 90 degrees, right, if you have a horizontal beam with the X-ray source on the left, in the sense from the right, for example.

Dr. Bill Cardoso:

The only difficulty, now, you have this flat object sitting vertically, and you didn’t have to put a jig or something you can slide, becomes more complicated, more cumbersome. It’s much easier if you let gravity help and just sit on a flat stage. But for example, remember the early days, we’d have people putting X-ray source on the top, remember, and then the sensor on the bottom, which is not a very good idea, because if you have, for example, your board, tall, electrolytic caps or connectors. That tall object, you go ahead and hit the source, causing considerable damage to the source or the sample or both, but it’s interesting over the years, they’ve converged, right, and pretty much everyone’s using the same source and the bottom sensor and the top configuration for electronics. And then, you have everything else, right? You have parts counting, which is a fairly new configuration. Some companies using source on the top, sensor on the bottom. So you have, like you said, a very high field of view. We’ve taken a different approach. We put the source on the bottom and sensor on the top, so we could have a mobile unit, not a unit that you need a crane, and you have to bolt to the floor because it’s so top heavy.

Dr. Bill Cardoso:

And it’s interesting that people, I know people might think that X-ray photons are impacted by gravity, right, because they think that putting a source on the bottom and the top changes the quality or the image itself. The only impact on the image, on X-ray images, the relative distance between the source, the sensor and the sample between. That’s all. Those X-ray photons are going to be flying out at very close to the speed of light, right, and now it doesn’t matter if they are shooting up, shooting down or shooting sideways. And at the end of the day, it’s a function of the sample, right, and that’s why once in awhile, regularly, we get people come to us saying they’re going to buy machine X to inspect a sample. And we’re like, “What are you trying to accomplish here? Who told you that’s a good idea.” It makes no sense. Like, for example, I guess for a horizontal beam to expect a PCB doesn’t make any sense, right, because it’s just the wrong approach, there are much better approaches elsewhere. And then, or a vertical beam to expect a heavier sample, right, engine casting, things that you really want to be able to move it around.

Dr. Bill Cardoso:

And again, we don’t use gravity, right, because gravity is one of the few things that we know works everywhere on Earth for now. I don’t know if that might change in the future, but for now, we’re pretty sure gravity works pretty much anywhere within a certain distance from Earth, so we might as well use it, right, to your advantage.

Dr. Glen Thomas:

And then there’s some of the older systems, the reason you saw such diversity back in the day, say in the late 80s, early 90s, a lot of the systems were film based systems being converted to real time systems, and in a film system, it made sense. You had the source on the top, you had the detector, which was a sheet of film placed in the bottom of the cabinet. And you suspended the sample somewhere in between. The easy thing to do was to put a real time or put an image detector in there, like image intensifier, so that just carried over, and it was more of a copycat concept. That’s how we do it, and everyone copied it for a while, until we started really getting into the imaging of electronics, then we started to understand exactly what needed to happen. And then, now you start to see some changes in the concepts of how an X-ray should be produced for an electronic application.

Dr. Bill Cardoso:

Yeah. Because most medical systems are contact magnification. For the most part, you’re not magnifying, you’re just taking as much field of view as you can. And those are the precursors to… Those use films. So everything migrates from that trend, and then as time goes by and technology evolves and the industries grow, you can start specializing, right, in creating machines to specific vertical, specific industry.

Dr. Glen Thomas:

Yeah. It’s just medical X-ray, you don’t want any magnification, as little magnification as possible because you could inadvertently give someone an enlarged heart. They’re going to rush right over to surgery, and it’s like, well, what do you mean I gave him three times magnification on that image, right?

Dr. Bill Cardoso:

Yeah, exactly.

Dr. Glen Thomas:

So that’s one of the major problems when we started out in the electronics industry, X-raying electronics, was the transfer of the technology and the image based stuff. Because if you remember, a lot of contract manufacturers in the early days would go to the hospital and stand in line and get an X-ray of their prototype boards. So a lot of that X-ray technology just carried over, the concepts and the thought processes, and some of the young companies. It was back in the day. Some of us didn’t have a clue what we were doing when we started the X-ray business, right?

Dr. Bill Cardoso:

Yeah. It’s true. Yep, and even in hospital, you’re going to see vertical systems and horizontal systems, right. Hospitals have both, right, and horizontal system if you take a long exposure, very likely is going to be horizontal, a horizontal beam. So the beam, the X-ray source is here, the film or the digital plates going to be sitting vertical, and you basically stand in front of the plate for an X-ray. And that has to do with the sample, your lungs, right, and how the radiologist is expecting to see the organs inside your body shaped, and if you take again gravity, and you move it around, they’re going to be shaped differently. Things are going to be obstructing each other, so you want to have objects facing a specific way.

Dr. Glen Thomas:

Absolutely. So does that answer your question, David?

Dr. Bill Cardoso:

What was the question again? I keep forgetting the question after a while.

David Kruidhof:

Beam direction.

Dr. Bill Cardoso:

Beam direction, that’s what it was. Got it. I think we did. I think we answered the question.

David Kruidhof:

Yeah. I think Glen answered it, and then Bill talked some more.

Dr. Bill Cardoso:

Yeah. That’s usually how it goes.

Dr. Glen Thomas:

All right. We could go down a rabbit hole and talk for hours.

David Kruidhof:

Yeah. But Glen said something at the end of that, that was specially interested in about electronics, used to take their boards into the hospitals to get an X-ray, right? That’s not a story I’ve heard before, but I definitely believe it because we still run into customers that do the same thing in different industries, where it actually hasn’t really permeated that industry. They’re taking their armor plate to the dentist and the doctor to get an X-ray of it, so how that’s it going?

Dr. Bill Cardoso:

Yeah, and if the armor plate has a good health insurance plan, might be covered.

David Kruidhof:

Yeah, exactly. It would be a free X-ray.

Dr. Glen Thomas:

Insurance claims from the owner of the company go up drastically. Hey, why do you have 700 X-rays last month?

Dr. Bill Cardoso:

Exactly.

David Kruidhof:

That brings us to our next question, which is a little bit more fun. What are some interesting things that you have inspected under X-ray, what kind of cool stuff have you looked at, I know Bill’s got some pictures behind him, but…

Dr. Bill Cardoso:

Oh yeah. We can see if people can figure out what those things are.

David Kruidhof:

Yeah. There you go. A little hard from this vantage point, but…

Dr. Bill Cardoso:

What do you think Glen? What interesting things have we X-rayed with who we’ve X-rayed?

Dr. Glen Thomas:

Of course, I’ve X-rayed quite a variety of things, right, from animals, dirt, believe it or not, to Barbie dolls, and then there is the ability to, or the X-ray’s imaging of product is unlimited. At some point in manufacturing, in every manufacturing sector, there’s a need for X-ray. So I’ve X-rayed components of food. We’ve X-rayed food. I had an application one time where we X-rayed 10,000 loaves of bread. Somewhere along the way, they’ve lost some stuff in bread, right, and they were looking for that pencil or that pen in the loaf. It’s in one of those loaves.

Dr. Bill Cardoso:

Or hairnet or nail.

Dr. Glen Thomas:

Inside a glove. How did that glove get in a package of coffee. There’s a glove and a package of coffee, watches, die casting, especially die casting. Probably the most interesting thing I X-rayed, at least at the time, were brake pads for the space shuttle. They were a carbon type based pad, and it seems they broke off some needles in some of those pads, and they needed to find the needles, so we X-rayed a bunch of those. So the application is endless, foodstuffs, electronics. Actually, electronics and BGAs are probably the most boring thing we ever X-ray. A BGA is a BGA. It’s got how many balls. It needs to be circular, it needs to not have a lot of voids in some of the other applications that are most exciting. One of them that most people don’t realize is the insurance industry. Items that are in fires essentially. You’ll have an insurance investigator come in and take the electrical components out of your house, electrical appliances, and they will take them back to a warehouse and X-ray them to determine the cause of the fire. Forensics is a huge thing. You start looking at art. Art is another interesting one when you can actually image a picture underneath of a picture. That’s always interesting, so there are all sectors that we can touch, and…

Dr. Bill Cardoso:

I have one of those examples on the website, on our website of how the X-ray revealed a different painting underneath from the great masters.

Dr. Glen Thomas:

You want to share the dog tags. That was an interesting application, right?

Dr. Bill Cardoso:

No, go ahead.

Dr. Glen Thomas:

No, go ahead. That was your deal when we did the unclaimed dog tags.

Dr. Bill Cardoso:

Unclaimed dog tags, that was a very, very interesting project, is an organization that collects dog tags from World War II, and especially World War II in Europe and the Pacific Islands, and their mission is to reintroduce or offer dog tags to family of the owners, and for the most part, soldiers that have perished in second world war battlefields. So we received a batch of those dog tags because the weather, rust and overall aging had all but completely destroyed the dog tags. So there was no visible identification that we’re able to identify who the dog tag belonged to. So using a X-ray, we were able to cover some of the inner layer imprint of the dog tag and reconstruct and find who those I.D.s belong to you, and we’re able to reintroduce them to the family of the owners. These are all soldiers that died in the battlefield. So it’s a very touching project, and one of the many ways X-ray inspection can help people.

Dr. Glen Thomas:

That’s one of the key… You talk to someone about X-ray, and for the most part, in the medical industry, nobody knows that there’s industrial X-ray available, right? It’s a huge part of the medical industry, but if you tell someone from the medical industry that, “Oh, I’m in the X-ray business.”, They say, “Are you a radiologist?” “No, not quite.” And you explain what we do, and they are quite shocked that there is a complete industry that is X-raying product, not only finished product, arch presence placement, no quality control, archeological. You look at some of the agricultural applications, right, looking at seeds and looking at seed viability and root viability. So the industrial X-ray industry is huge, so I get dropped off one time at an oil rig in the middle of the Gulf of Mexico, jumped out of a helicopter to show a bunch of guys how exciting it would be to X-ray the pipes. So, interesting thing, so there’s always an application that we’ll run into that just like, I’ve never seen that before, that’s influencing, and then there are a few that actually stand out, right? Especially when you come home and you say, “Yeah, don’t buy that anymore.” We don’t buy that anymore. Based on what I just saw.

Dr. Bill Cardoso:

Yeah. We had a few of those that shall remain nameless, right Glenn, for this presentation.

Dr. Glen Thomas:

Let’s not buy those anymore.

Dr. Bill Cardoso:

That’s funny.

David Kruidhof:

Yeah, sometimes, my kids will send me to work with stuff to X-ray. The other day, Luke found a dead lizard from the ground, like, “Here, dad.”

Dr. Bill Cardoso:

Actually, I saw those images on the website.

David Kruidhof:

Yeah, we put it on the gallery.

Dr. Bill Cardoso:

It was all dark spots inside the lizard.

David Kruidhof:

Yeah. I was trying to figure that out because his fingers were going under his belly, but there are some really dark spots. I was trying to figure out what it was. I’m not sure if he swallowed something he shouldn’t have or what?

Dr. Bill Cardoso:

Just for the record, the lizard was there before Luke found it, right? Just make sure that. People we get upset. It was already dead, dead of natural causes, right.

David Kruidhof:

Hopefully.

Dr. Glen Thomas:

So, I had an application. I ran into a guy 20 years ago that was doing X-ray art. I gave him an X-ray system, and he was actually doing some X-ray art of flowers. And he had actually was quite successful at it. He was a medical, radiological technologist, and he actually had some showings on projecting these X-ray images of flowers on six story buildings in some of these cities. He did some stuff. So even in some cases, X-ray can be art.

Dr. Bill Cardoso:

Yeah. Look here. This is beautiful art we have all over the place.

Dr. Glen Thomas:

Exactly

Dr. Bill Cardoso:

One application that is still impresses me when we do is counterfeit detection, and we have, is it next week, David, when do we have the counterfeit conference. It’s coming up, right?

David Kruidhof:

I think it’s two weeks.

Dr. Bill Cardoso:

Two weeks. Okay, well checking the website, it’s got to be there somewhere. We have this symposium every year to go and to get together and talk about counterfeit detection methods and technologies, but it always baffles me how creative and how industrious those criminals are. It’s unbelievable. Just recently, we did some counterfeit detection for the fashion industry, right, which is not where most of us circulate in a daily basis, but you see how well made those counterfeits are, but with X-ray, you can find the inner works in the building, in the construction of those things, and you can tell them they’re fake, but it always impressed me, and with electronics, we’ve been doing that for what, 10 years now.

Dr. Bill Cardoso:

I think the trend is that they’re getting better, so you look at your electronic components that look exactly the same, and the internal construction can be completely different. So it’s a testimonial, I think, for the sophistication and technology that the counterfeiters have nowadays to sell fake components, especially in times of crisis, right, when you have the ups and downs of economies, when the counterfeiters benefit the most, because every time you have a disruption to supply chain, right? You have a gap of demand over capacity? Those are the gaps that counterfeiters fill and profit.

Dr. Glen Thomas:

Right. Some of the disturbing part of that is some of the dollar values that they’re starting to counterfeit now.

Dr. Bill Cardoso:

I know, it’s nuts. Yeah.

Dr. Glen Thomas:

$1,000 or $50,000 handbags. It’s $10 items.

Dr. Bill Cardoso:

Yeah, or capacitors.

David Kruidhof:

That’s the scary part is the prevalence of even the low dollar items being counterfeited.

Dr. Bill Cardoso:

Yeah. It was back to their sophistication, that they can achieve such volume, right, that justifies. They can achieve volume with that scale. With that scale, they can still be profitable by counterfeiting such low cost items is just incredible.

David Kruidhof:

And they can earn the 20% more or whatever, by calling it a name brand versus calling it an off brand. We just helped that guy out with his blog about Oliver.

Dr. Bill Cardoso:

Oh yeah. Oliver stocked with the dongle, right?

David Kruidhof:

[crosstalk 00:27:53] doctor, right? The people who made that could have just sold it as an off brand. People would still buy them, right? They went through all the trouble, and the box looked remarkable. The connector itself was decent. Once you X-rayed, it was… I think those are 10 bucks new from Apple.

Dr. Bill Cardoso:

Nah, it’s a little more than that I think.

David Kruidhof:

Okay.

Dr. Bill Cardoso:

Yeah. I don’t think you can buy anything for 10 bucks at Apple.

David Kruidhof:

Yeah. The level of sophistication they’re willing to put in to make, impressive.

Dr. Bill Cardoso:

And at the same time, if you look at the device from Apple, it’s a lot of electronics in there. So also, the phones can identify that that’s not a legit component, so there’s both sides that play in a very interesting way. But again, very high level sophistication, right, to fake a product.

David Kruidhof:

Yeah.

Dr. Bill Cardoso:

David, can you put down on the comment or whatever description, the links to all those things we talked about?

David Kruidhof:

Yeah, definitely. And just for reference, that symposium is August 4th to 6th, the virtual conference.

Dr. Bill Cardoso:

Virtual, of course. Everything is virtual now. Yeah.

David Kruidhof:

All right. Well, thank you all for joining us.

Dr. Bill Cardoso:

We’re done already. Well, that was fast.

David Kruidhof:

But thanks bill. Appreciate your time. Thank you, Glenn.

Dr. Bill Cardoso:

Thanks guys, until next time.

David Kruidhof:

Thanks to everyone for watching and joining us, and we’ll see you next week.

Dr. Glen Thomas:

Thanks.

Speaker 4:

Creative Electron.