Learn more about how these object were scanned: www.lumafield.com/article/ct-scans-vacuum-tubes-tested-adam-savage Check out the Lumafield CT scans for yourself! Thyratron tube: app.lumafield.com/project/1154c69a-1aa0-4c50-81a7-0f2da22a2d79 Photomultipler: app.lumafield.com/project/63775e74-3841-4f68-ba1f-179194abe27f IGBT module: app.lumafield.com/project/a165af93-8d96-4c7f-97e4-ebafcf4731d9 3D printed shoe: app.lumafield.com/project/13e969bc-12fa-4490-a8ec-4b6155efd7ff
great video and I love the channel, Unfortunately i can't afford to join or become a patron but if my situation ever changes i definitely will because these videos are the highlight of my day. Thank you for continuing to offer as much free content as you do so people like me who are not in a position to join get to enjoy these fantastic videos.
CX1538 is a Thyratron tube designed for 10kA for 15usec when turned on. When off, it can withstand 27kV between anode and cathode. It can be used for discharging capacitor for accelerator or pulse mode Klystron tube. The thyratron tube label can be see on 9:46. Thank you so much for your afford.
Hi Adam! As someone who built the Thyratrons by hand for 5 years I may be able to help too! All aspects of the thyratron we made by hand - the glass tube starts as 2 parts; the top we would attach to the inner first then once completed the tube would be added. Everything inside; from the ressies which we filled by hand, heaters & cathode which surrounds the heater were all made on site. There’s also a mini version that we made too which is the same device, just on a smaller scale. The stacked disks inside we welded onto the mesh with a small foot pedal welder, same for the mesh around the cathode (which is also painted!) and everything had to be perfect - scratches or dents would not pass and the items would have to be disposed of. If you opened one up, inside the stacked disks is a smaller disk and each of the staff who made them will have scratched their initials into them for traceability reasons (as the batches of everything used was recorded!) - I left the business around 6 years ago but could still make a thyratron in my sleep! Thanks for sharing the video!
They’re still made on site daily! We were tasked with 7 of the large & 12 of the small every day, when I was there, we had 5 of us producing the final product before it went to the glass shop so there’s loads of them around!
If Adam's photomultiplier is indeed space hardware would @curiousmarc (who visited you with some Apollo gear earlier this year) be a good guy to help identify it? Could be fun to get them together talking all things space related.
The Thyratron you have there was made in Chelmsford in Essex, UK by EEV, English Electric Valve. They are all hand made and tested and yes that glass is blown and sealed by hand. I work for the the same company now called Teledyne e2v and we still make these. They are used on equipment such as radiotherapy machines. 😊
Were they also used in neutrino detectors back in the 70's - 80's ? I recall thousands of something that looked like these in a subterranean array attempting to detect neutrinos striking in a tank of essentially dry cleaning fluid.
@JeffPDX1 I believe similar ones are still used today for that purpose, we don't have anything better to detect singualr electrons. CCD's in cameras are way too noisy
I'm speculating, but I would expect a master level physics student to have this level of competency. The other is electrical engineers, especially those how enjoy high voltage. Most of them have dabbled with x-ray tubes, PM-tubes etc. From the fact that Lumafield does cone-beam-CT(X-ray), I suspect he falls in the latter. And a physicist would probably linger on the photo-cathode and photoelectric effect. The electrical engineer goes straight to the dynodes. The charisma though, that's all him.
That knowledge is not taought in schools or universities as far as I know. I guess he has taught himself a lot autodidactically and or has worked in a physics institute. Fortunately there are many old books about vacuum tubes, of which many have been scanned and archived online, such as "Vacuum Tubes" by Stanford professor Spangenberg from 1948.
If you're a passionate engineer being able to look at an object like this would definitely inspire you to learn about it, even if you had no prior knowledge about the device.
@@maeanderdev Or he is simply old enough to have learned it in college. I did. Any competent electrical engineer should understand basic vacuum tubes, because they are easy to wrap your head around, and then you can leverage that understanding to FET's and other solid state devices. I mean your basic diode or triode is pretty easy to understand. After all it's just electrostatic attraction and repulsion along with a certain amount of geometry. Which is also (coincidentally) how solid state devices work!
It should be noted that the 1000A current rating of the thyratron is a PULSE rating, with a very small duty cycle. Average current through a tube of that size might be an ampere or 2. On the photomultiplier, the conversion of photons to electrons takes place on the photocathode, a chemical coating on the inside of the front glass window. A thin layer of cesium or similar material.
That thousand amp rating was really thrown me for a curve, I was thinking there's no way this thing can handle that without turning into a ball of plasma itself. Any idea on the pulse length?
I own a thyratron just like that one. The heater is 6v at 20amps. And the peak frequency is 1,200 per second. The pulse time of each of those 1200 pulses per second is very small. They were used to power magnetrons for radar.
@@jaeweld19 it threw you for a curve for a good reason, it was pure gibberish. 10A is what something like that would have run, at probably 1500v. 100A peak pulse.
hey, this was super interesting! small correction/addition: the honeycomb pattern on the bottom of the IGBT Module is the thermal "paste" already, it's called a phase-change TIM (thermal Interface Material) that turns into a paste when heated. I think it's made with a kind of wax. that way they can pre-apply the TIM at the IGBT factory in the correct density (note differently sized gaps in the honeycomb!) and not worry about uneven/incorrect application when mounting the module to something. that's also why those modules need a kind of burn-in when using them the first time, to melt the TIM.
I’ve worked with vacuum tubes for a living for 20 years. They are far from primitive. And you’re right, they have had extreme amounts of engineering and physics know-how poured into them for about 100 years now. Solid state is just now starting to stretch into some of these technological strongholds, but it will be decades, if ever in the next lifetime, that they will replace all vacuum tube applications. The higher the frequencies and power, the smaller the wavelengths and solid state physics start to struggle, especially at heat removal from those extremely tiny solid state structures.
I'm a medical linac engineer and thyratrons are amazing devices, so cool to see in one! The ones we use from e2v are a ceramic package so they're inscrutable already... Really cool to have a look at the scan!
Its great listening to someone speak so enthusiastically about what they do. I honestly think I could listen to this guy talk all day. Thank you Adam for another great video.
As a forklift service tech listening to them describing the operation I thought, "that sounds like an SCR". I don't think I have heard them referenced outside of DC drive systems, so it was cool to hear it actually said and described. Very cool.
I highly recommend the behind the scenes tour of the shed aquarium in Chicago! They give you a very well educated guide and you get to see all the plumbing and lighting and filtration! It's wild back there!
As a nuclear engineer, photomultiplier tubes are really cool, because they are still in use, and don't even have a replacement. The ability to detect a single photon, and amplify it to a measurable electrical signal is how scintillation - a form of radiation detection and measurement - is accomplished. Using a polymer or - for ultra-high resolution - high purity germanium crystals, individual particles interact with the material to produce a photon with a wavelength proportional to the energy of the incident particle. This can be used to measure the individual energy peaks caused by different sources to identify various isotopes, as well as their relative abundances.
My son is applying to do his senior year at a state tech school. We went and visited the school and they had got a $10million dollar grant from the department of defense and it was for their 3d printing department and not only do they have metal 3d printers and the best of the best but also have this machine and I was so excited to explain what it does and tell the students and their parents I learned about it from Adam Savage's YT channel. My son's in engineering program at his tech center and I really hope he gets in to this program. Hell not only graduate from his high school but will get his 1st year college credits (30) We will have to pay for his room and board ($14k) and food but I'm willing to get a second job if he's accepted. I grew up with nothing in foster care and my son has a future. I couldn't be prouder.
I'm guessing they cut the part where Adam said "How much for one" and "where can I get it"... Honestly, I could see him spending DAYS at the cave scanning everything! "Sorry, won't be home for dinner, scanning an impact driver..."
(It Would be a HELL OF A LOT of Dev Work + One Would Need to Do Safety Stuff (Shielding/Interlocking) + It Would Probably Still be Decently Expensive and/or Not As Capable), BUT: *A Fully Open Source Industrial CT Scanner would be cool af* It would be great for a “Reverse Engineering Lab” section of a Makerspace (or my “Big Box Store Sized Makerspace” idea lol) (Edit: Typos)
@@ericlotze7724 Safety yes, but I don't think there wouldn't be a lot of dev needed since it's already a built product. Probably needed for the processing, but a bare bones 'mini scanner' would likely be 'easy' (NOT easy...). I think the hardest part would be if you decide to follow things like 'rules' or 'regulations'...you know, the pesky stuff that keeps people from doing things like powering your own home with a mini nuclear reactor... ;)
@@bobd2659 I wouldn’t be doing anything like Injection Mold Design / Casting Mold/Lost Wax Casting Design / Intense Production Engineering (Assembly Lines+Large Scale Logistics and so on) etc, so that would save *SOME time*, and for ultra-basic machinesApplied Science etc have pulled that off with not as much dev time as some full on replicatable workhorse machine. And granted it would be tedious,, and i would prefer not to use lead (supposedly Beryllium is a lesser, but still better than most, radiation shielding material), so shielding may require a bit of time, but honestly a mix of Room Interlocking (ie you must be 10 meters and a wall away before it can run), and just basic materials (huge pile of steel, etc) should work. I’d imagine the majority of the work would go into Motion System Design (Probably similar to Existing Open Source Polar 3D Printers I’d Imagine) (Could Maybe Even Adapt “Open5x” for 5+ Degrees!), Tube+Sensor Choice/Calibration, and Firmware/Software (*Sorted that mess above by increasing complexity/time needed (in my armchair napkin math estimate) *)
I can truly relate to Adam’s love and excitement of “pealing back the curtain back on the world”. I do 3D LiDAR scanning/documentation to support engineering design. This allows my team to get into some amazing environments. Seeing the CT scan of the tubes is very interesting!
In the field of nuclear medicine these PMTs are used to detect gamma rays from an injection of a radioactive material into the body (Usually Tc99m). We are able to see where the nuclear isotope has traveled in the body thanks to these. They are constructed into a lattice and contained within a device called a gamma camera.
Ahhh.. vacuum tubes... The first radios I took apart had transistors, but the first radio I built in high school electronics had vacuum tubes. Thanks for taking me back Adam! BTW.. my first RF power amps as a design engineer were on ceramic substrates with through-hole PCBs. We were using SMDs a year later. Tech changes fast!!!
I think the photomultiplier is back to the medical imaging industry. The first CT scanners I worked on used them, but not like that one. However, although I never worked on them, I reckon that one would have been used in a "Gamma Camera". It would have been mounted in the 'head' with maybe a dozen similar tubes. Being hexagonal, they can 'nest' with at least six others and thus many more in the spaces available. In front of the array of tubes would be one or more crystals, sodium iodide if I recall. As the Gamma particles from the patient - they are injected with a radioactive isotope - hit the sodium iodide, they interact with the molecules and the crystal emits photons. The photomultiplier amplifies the signal photons with a gain of probably 10,000 and generates a reasonable electronic signal directly proportional to the distribution of the isotope. From the array of PM Tubes, an image can be generated. I believe the young man said modern solid state SCR's "were not made to handle this voltage and current." Well, maybe, maybe not. One of the CT's that I worked on (From the mid eighties into the nineties) used a solid state SCR to 'fire' the current the xray generator tank would use to apply across the xray tube. Up to 140Kv - 140,000 volts. The SCR wasn't switching that - it switched the primary current - but it was a huge ceramic device (same sort of stuff as a spark plug) that would audibly "tick" when it was fired! None of it is like that now, it all goes on in oil filled tanks rotating with the xray tube inside the scanner.
Hi Adam I love your Chanel. I am in the uk and am disabled but you give me a chance to do things and learn things that I have never thought about. Absolutely brilliant . Thanks
As an X-ray tech, this is such a fun video! Its cool to watch this while already having some understanding for the way the engineering and physics works for both the CT scanner and the photomultiplier tube.
I read somewhere the thyratron was used as part of the ignition system in some WW2 bomber engines. The modern equivalent is the Silicon Controlled Rectifier, also known as a thyristor. I don't think that particular thyratron could carry 1000 amps continuously because the wires are far too thin. Instead it would be more of a current surge of 1000 amps, e.g. maybe for 100 milliseconds.
It was probably 10A nominal, less than 100A surge. No way it was ever rated for 1000A. Also it was probably in the 1500V-2000V range. I don't think he had a very good understanding of basic physics if he thought that sucker could pump out a kA.
Thanks to Savage and Tested for sharing this type of content! I thoroughly enjoy watching videos about weird or niche electronics. I currently work in the high-power electronic industry. I’d really like to see more of these videos featured here. 🙂⚡️Thanks for bringing this one to us.
Fascinating episode, would love to see more collabs with them! And a design implementation you didn't notice was that the photo-multiplier has a hexagonal "head", implying that many can be set up in an array.
As a point of perspective for folks regarding how nutso the currents that Thyratron tube can handle are- 1,000 amps at 25,000 volts makes for 25 *megawatts.* For context on how insanely massive that number is, a typical US house with every single circuit drawing its rated maximum load will only pull in the neighborhood of 50 kilowatts- in other words, you'd need something like 500 houses all pulling as much power as they safely can just to max out that tube's capacity.
@@MostlyPennyCat From what they said, it sounds like it's essentially an ultra-high voltage relay that can't be shut off without cutting power elsewhere. Truthfully, I don't entirely understand how that's useful, but it sounds like modulation might be possible?
@@HexagonaldonutIt works like an SCR. If used for phase control (like a light dimmer) when the AC waveform crosses zero (120 times per second in a 60 Hz system) the current stops. To use them in a DC to AC inverter, usually the output stage is arranged so turning on one tube interrupts the current in the one that is currently on, turning it off.
More like 25kw - 120v * 200A service = 24,000w or 24kw. And 200A service is kinda modern, a lot of older houses have 100A or even 80A service, so 10 to 12kw.. so 12,000w vs 25,000,000w And thats why Doc almost has a heart attack when he hears 1.21 jiggawatts 😆.. 1.21 gigawatts is like 1,210,000,000w, meaning the flux capacitor is a tube 1000x more insane than the one shown
Adam, check out Glasslinger’s channel. A very skilled artisan with long form demonstrations of how these types of tube devices are made. The channel is a gold mine of obscure knowledge and techniques. I highly recommend. Cool video brother!
Fascinating it just amazes me how this stuff got figured out to get the job done and then the next task is to make it smaller. Probably the next step will be how small will the next requirement need to be before the quantum mechanics say nope you’ll need understand the physics that is currently unknown before you can go smaller or build it in another dimension.
It's so cool! @CuriousMarc grade stuff :) Photomultipliers are still used in all kinds of analytic gear that use infrared, visible and ultraviolet light, mostly spectrometers, though CCD sensors are also used there.
Early night-vision scopes used 'channel plates' that exploited the photo-multiplier effect in an array of narrow, angled metal lines holes. Each hole was sort of a continuous dynode, a voltage gradient across the thickness of the plate powered the thing. Each channel made a pixel, which was projected onto a phosphor screen.
Ya know... I love seeing Adam have to ask a ton of questions to understand something he owns, but actually knows next to nothing about. It's a beautiful thing, the human mind. and those tubes. XD
Thyratron. And it is indeed a high power switch, uses Townsend Discharge, which I believe is also the working principle behind the much cooler Mercury Rectifier. You should definitely get one. And then be very careful because they can kill you in multiple exciting ways.
Thanks for bringing in a couple of vacuum tubes for them to scan. Way back in the day I worked for Teledyne MEC (I'm talking around the late 70's) and wound the helix for thier traveling wave tubes. I was probably around 16 or 17 at the time and didn't really know what they were for and really still don't. But thanks for triggering those memories of my youth. It would be great to see one of those scanned.
The big neutrino telescopes still use PMTs (photo-multiplier tubes) for detecting very very low photon fluxes from the huge scintillator tanks they use for neutrino detection.
I too am fascinated by infrastructure. The basements, attics, steam tunnels, and mechanical rooms of the world fascinate me. I am so glad to hear of your interest in these, too!
I was thinking just this - Not sure Adam has ever looked into it, but I think he would love the design aspects of classic hand wired amps both in the circuits (valves, transformers, etc) and cabinet design.
This is awesome. I've been getting into tubes lately and want to make a tube amp for my turntable as a DIY project. Tubes are so much cooler than solid state parts.
I can only imagine the thought processes that were part of designing such a device, and to generate its own hydrogen! Just part science part alchemy and a little wizardry. Awesom😅
That EEV CX-1538 thyratron was a bespoke part for the LLNL Advanced Test Accelerator. It was developed and tested to handle peak currents in excess of 10,000 amps, although was put into operation at only 2,500. Six were used together in a chassis to switch a capacitor charged to 25kV into a 1:10 transformer to charge a Blumlein to 250 kilovolts, which was in turn switched by a gas-blown spark gap into an accelerator cavity to deliver 250keV acceleration over a 70 nanosecond pulse. Such modules were stacked 190 deep for a 50MeV electron beam.
I want to make a small chemistry comment! Hydrogen is _in most cases_ less of an escape artist than Helium is, because most hydrogen gas we encounter is the dihydrogen molecule. Because quantum physics, it's hard to exactly compare the sizes of atoms and molecules (they require different metrics, thus making it hard to compare), but in pretty much every case helium is **smaller** than dihydrogen, by a pretty significant factor I believe. Of course, hydrogen is still a crazy escape artist, but it can't quite beat helium. (Cases where we don't see hydrogen as dihydrogen include in space! Most of the hydrogen in the universe is, in fact, monoatomic hydrogen, but Earth is our special case home.)
I believe you're right. I was thinking that at high enough temperatures (excluding plasmas) might separate into individual hydrogen atoms. I can't seem to find if that's true. Buuuut... looking at the Wikipedia article, it appears the thyratron operates by the hydrogen being turned into a plasma. I'd suspect a proton is a pretty good escape artist in this case, even better than helium.
It’s amazing to see technology shrink down like this. Maybe someday a CT scanner will be a thing anyone can buy, and this is a neat step in that direction.
When you talk about the development of the thiotron: the math, the schematics, the failed attempts.... I'm immediately thinking of the huge breadboard that incorporated all the elements of this device and the tests that caused changes to the breadboard, until they had a working model. Then the iterations of reducing it in size to fit in a smaller package.
I have an extensive collection of specialty vaccum tubes, if you want to show more on the channel I can help with that. Some highlights as Wanderfeldröhren by Siemens (used for satelite transmissions), photomultipliers, TV camera tubes and the elusive lorentz Napfröhren.
You put a scintillator material on the front of the photo multiplier to detect certain types of radiation. The chemical releases photons when the radiation hits it and the PM detects the photons.
I worked for a company in the UK that maufactures photomultipliers. Electron Tubes is now a subsiduary of Ludlum Measurements Inc.. At one time RCA was a leading manufacturer, as well as Phillips and Hamamatsu in Japan. Electrons are "generated" by the photon or photons interacting with an electron emmisive layer, the photocathode, which is deposited on the inside of the front window when the photomultipler is made. Electrons are "knocked" out of this layer and electrostatically focused, as stated here, onto the dynode stack. Each dynode is held at a higher potential than the preceding one. This "attracts" the electrons and focuses them, by the electrostatic field generated, guiding them down the stack. At 5:37 in the video, to the right of the end of the glass envelope inside the spring, you can see what is probably a chain of resistors, on a PCB, which is used to generate the voltages required. There can also be other electonics on this PCB which may be used to condition the output signal. To detect photons that would be blocked by normal glass, in the UV part of the spectrum, the front window can be made from quartz or so called solar blind ones using magnesium fluoride. Different photocathodes are used to enhance the photomultipliers sensitivity in the IR, visible and UV parts of the spectrum. Again at 5:37 in the video, just below the dynode stack, you can see the slightly blurry shapes of the "generators" which contain the chemicals that the photocathode is created from during the "processing" of the tube. A great deal of mechanical engineering, glass processing technology and sophisticated chemistry goes into making a photomultiplier. Photomultiplers are still used extensively in the particle and high energy physics fields as well as astronomy, pollution monitoring, process control and medical physics, to name but a few.
The Philips photomultiplier tube is used in nuclear medicine. It detects faint flashes of light emitted by a gamma particle as it passes through a crystal. Usually about 50-60 of those photo multiplier tubes (PMT's) are situated in a large detector to capture gamma radiation emmited by radio isotope injected patients. Then a computer uses that data to create a 3D image of anatomy in question.
There aren't many devices that still use photomultiplier tubes nowadays. I'm sure there probably are spacefaring applications for these things, but chances are pretty good that this one was used in nuclear medicine. I reckon it might have come from a gamma camera or a SPECT or PET scanner, which Philips does actually make. Just in case you're wondering what nuclear medicine is, it's very similar to radiology, the difference being that radioactive tracers are administered to the patient and the scanners themselves don't emit radiation, whereas in radiology, a CT scanner fires X-rays through the patient and looks at what comes out of the other end.
Adam: if you ever get a chance to do that again, could you have him scan a klystron and explain to me how that works? Because its the closest thing to dark magic in a radio amplifier to me.
Many of the only klystrons in the world are owned and operated by NASA JPL, and are very fascinating devices! An overly simplified (and somewhat incorrect) explanation of their workings is a super high power microwave oven, but it focuses light (radiation) rather than cooking with it. I don’t recommend you stand near one when it powers on.
@@GearsAndBricks I don't know if they still are, but they *were* one of the last stages of UHF television transmission. When I first started looking into the processes of television transmission, I ran across the term, looked up the device, and was kinda blown away by how they look.
Oh yeah! I forgot about the television industry! 😂 Yes, they were (and still are) used everywhere. It’s difficult to find information about klystrons, though. I work in the industry, yet I don’t know everything i’d like to know… 😅
![Lp. Сердце Вселенной #1 НАЧАЛО ПУТЕШЕСТВИЯ [Новый сезон] • Майнкрафт](http://i.ytimg.com/vi/380Q7gLWGvk/mqdefault.jpg)
Learn more about how these object were scanned: www.lumafield.com/article/ct-scans-vacuum-tubes-tested-adam-savage
Check out the Lumafield CT scans for yourself!
Thyratron tube: app.lumafield.com/project/1154c69a-1aa0-4c50-81a7-0f2da22a2d79
Photomultipler: app.lumafield.com/project/63775e74-3841-4f68-ba1f-179194abe27f
IGBT module: app.lumafield.com/project/a165af93-8d96-4c7f-97e4-ebafcf4731d9
3D printed shoe: app.lumafield.com/project/13e969bc-12fa-4490-a8ec-4b6155efd7ff
its a fancy flesh light
great video and I love the channel, Unfortunately i can't afford to join or become a patron but if my situation ever changes i definitely will because these videos are the highlight of my day. Thank you for continuing to offer as much free content as you do so people like me who are not in a position to join get to enjoy these fantastic videos.
3d scans? So Adam gonna bring a VR headset next time? So he can experience the object in 3d space.
CX1538 is a Thyratron tube designed for 10kA for 15usec when turned on.
When off, it can withstand 27kV between anode and cathode.
It can be used for discharging capacitor for accelerator or pulse mode Klystron tube.
The thyratron tube label can be see on 9:46.
Thank you so much for your afford.
Hi Adam! As someone who built the Thyratrons by hand for 5 years I may be able to help too! All aspects of the thyratron we made by hand - the glass tube starts as 2 parts; the top we would attach to the inner first then once completed the tube would be added. Everything inside; from the ressies which we filled by hand, heaters & cathode which surrounds the heater were all made on site. There’s also a mini version that we made too which is the same device, just on a smaller scale. The stacked disks inside we welded onto the mesh with a small foot pedal welder, same for the mesh around the cathode (which is also painted!) and everything had to be perfect - scratches or dents would not pass and the items would have to be disposed of. If you opened one up, inside the stacked disks is a smaller disk and each of the staff who made them will have scratched their initials into them for traceability reasons (as the batches of everything used was recorded!) - I left the business around 6 years ago but could still make a thyratron in my sleep!
Thanks for sharing the video!
Best comment by far. Do you have any of these devices left over?
They’re still made on site daily! We were tasked with 7 of the large & 12 of the small every day, when I was there, we had 5 of us producing the final product before it went to the glass shop so there’s loads of them around!
Thanks for stopping by, Adam! It’s always great to explore with you.
If Adam's photomultiplier is indeed space hardware would @curiousmarc (who visited you with some Apollo gear earlier this year) be a good guy to help identify it? Could be fun to get them together talking all things space related.
Every episode featuring your company is brilliant!
@@GrahamNicholson56 They'd definitely enjoy meeting!
@@pixiniarts Thank you! We're glad you're enjoying these.
Thank you for sharing this technology with us and giving us a unique peek behind the curtain of some already amazing devices!
The Thyratron you have there was made in Chelmsford in Essex, UK by EEV, English Electric Valve. They are all hand made and tested and yes that glass is blown and sealed by hand. I work for the the same company now called Teledyne e2v and we still make these. They are used on equipment such as radiotherapy machines. 😊
Were they also used in neutrino detectors back in the 70's - 80's ? I recall thousands of something that looked like these in a subterranean array attempting to detect neutrinos striking in a tank of essentially dry cleaning fluid.
So they help save lives? That's awesome (you're awesome, too).
Awesome Dawn.. Were you always the 'cool' kid?😊
Big up Dawn, that's real nerd food. And I don't mean that sarcastically. Thank you. ;-)
@JeffPDX1 I believe similar ones are still used today for that purpose, we don't have anything better to detect singualr electrons. CCD's in cameras are way too noisy
This gentleman was amazing. Does he specialize in these type of devices, or just happens to be a good enough engineer to know how they work.
I'm speculating, but I would expect a master level physics student to have this level of competency. The other is electrical engineers, especially those how enjoy high voltage. Most of them have dabbled with x-ray tubes, PM-tubes etc. From the fact that Lumafield does cone-beam-CT(X-ray), I suspect he falls in the latter. And a physicist would probably linger on the photo-cathode and photoelectric effect. The electrical engineer goes straight to the dynodes. The charisma though, that's all him.
Scott is a great engineer! :)
That knowledge is not taought in schools or universities as far as I know. I guess he has taught himself a lot autodidactically and or has worked in a physics institute.
Fortunately there are many old books about vacuum tubes, of which many have been scanned and archived online, such as "Vacuum Tubes" by Stanford professor Spangenberg from 1948.
If you're a passionate engineer being able to look at an object like this would definitely inspire you to learn about it, even if you had no prior knowledge about the device.
@@maeanderdev Or he is simply old enough to have learned it in college. I did. Any competent electrical engineer should understand basic vacuum tubes, because they are easy to wrap your head around, and then you can leverage that understanding to FET's and other solid state devices.
I mean your basic diode or triode is pretty easy to understand. After all it's just electrostatic attraction and repulsion along with a certain amount of geometry. Which is also (coincidentally) how solid state devices work!
Scott did a great job explaining the devices. He is clearly very knowledgeable.
Other than being wildly incorrect about almost everything involving the thyratron, yes, clearly.
It should be noted that the 1000A current rating of the thyratron is a PULSE rating, with a very small duty cycle. Average current through a tube of that size might be an ampere or 2.
On the photomultiplier, the conversion of photons to electrons takes place on the photocathode, a chemical coating on the inside of the front glass window. A thin layer of cesium or similar material.
That thousand amp rating was really thrown me for a curve, I was thinking there's no way this thing can handle that without turning into a ball of plasma itself. Any idea on the pulse length?
I own a thyratron just like that one. The heater is 6v at 20amps. And the peak frequency is 1,200 per second. The pulse time of each of those 1200 pulses per second is very small. They were used to power magnetrons for radar.
Probably 10A. 100A pulse/peak. No way it was ever rated for 1000A or more.
@@jaeweld19 it threw you for a curve for a good reason, it was pure gibberish. 10A is what something like that would have run, at probably 1500v. 100A peak pulse.
Ah, the undeniable joy of watching two learned geeks geeking out learnedly.
Their enthusiasm and excitement brought a smile to my face.
hey, this was super interesting!
small correction/addition: the honeycomb pattern on the bottom of the IGBT Module is the thermal "paste" already, it's called a phase-change TIM (thermal Interface Material) that turns into a paste when heated. I think it's made with a kind of wax.
that way they can pre-apply the TIM at the IGBT factory in the correct density (note differently sized gaps in the honeycomb!) and not worry about uneven/incorrect application when mounting the module to something. that's also why those modules need a kind of burn-in when using them the first time, to melt the TIM.
I’ve worked with vacuum tubes for a living for 20 years. They are far from primitive. And you’re right, they have had extreme amounts of engineering and physics know-how poured into them for about 100 years now. Solid state is just now starting to stretch into some of these technological strongholds, but it will be decades, if ever in the next lifetime, that they will replace all vacuum tube applications. The higher the frequencies and power, the smaller the wavelengths and solid state physics start to struggle, especially at heat removal from those extremely tiny solid state structures.
I'm a medical linac engineer and thyratrons are amazing devices, so cool to see in one! The ones we use from e2v are a ceramic package so they're inscrutable already... Really cool to have a look at the scan!
The thyratron pulses the magnatron to generate RF that we pump into the accelerator waveguide, the physics is really fantastic and interesting
Its great listening to someone speak so enthusiastically about what they do. I honestly think I could listen to this guy talk all day. Thank you Adam for another great video.
As a forklift service tech listening to them describing the operation I thought, "that sounds like an SCR". I don't think I have heard them referenced outside of DC drive systems, so it was cool to hear it actually said and described.
Very cool.
I highly recommend the behind the scenes tour of the shed aquarium in Chicago! They give you a very well educated guide and you get to see all the plumbing and lighting and filtration! It's wild back there!
As a nuclear engineer, photomultiplier tubes are really cool, because they are still in use, and don't even have a replacement. The ability to detect a single photon, and amplify it to a measurable electrical signal is how scintillation - a form of radiation detection and measurement - is accomplished. Using a polymer or - for ultra-high resolution - high purity germanium crystals, individual particles interact with the material to produce a photon with a wavelength proportional to the energy of the incident particle. This can be used to measure the individual energy peaks caused by different sources to identify various isotopes, as well as their relative abundances.
My son is applying to do his senior year at a state tech school. We went and visited the school and they had got a $10million dollar grant from the department of defense and it was for their 3d printing department and not only do they have metal 3d printers and the best of the best but also have this machine and I was so excited to explain what it does and tell the students and their parents I learned about it from Adam Savage's YT channel. My son's in engineering program at his tech center and I really hope he gets in to this program. Hell not only graduate from his high school but will get his 1st year college credits (30) We will have to pay for his room and board ($14k) and food but I'm willing to get a second job if he's accepted. I grew up with nothing in foster care and my son has a future. I couldn't be prouder.
What an incredible opportunity you are willing to provide for. Hope it goes well for the both of you!
Good luck to your son! Sounds like he's in for a treat at that program.
I'm guessing they cut the part where Adam said "How much for one" and "where can I get it"... Honestly, I could see him spending DAYS at the cave scanning everything! "Sorry, won't be home for dinner, scanning an impact driver..."
Guess I’ll have to DIY one then…
(It Would be a HELL OF A LOT of Dev Work + One Would Need to Do Safety Stuff (Shielding/Interlocking) + It Would Probably Still be Decently Expensive and/or Not As Capable), BUT: *A Fully Open Source Industrial CT Scanner would be cool af*
It would be great for a “Reverse Engineering Lab” section of a Makerspace (or my “Big Box Store Sized Makerspace” idea lol)
(Edit: Typos)
@@ericlotze7724 Safety yes, but I don't think there wouldn't be a lot of dev needed since it's already a built product. Probably needed for the processing, but a bare bones 'mini scanner' would likely be 'easy' (NOT easy...). I think the hardest part would be if you decide to follow things like 'rules' or 'regulations'...you know, the pesky stuff that keeps people from doing things like powering your own home with a mini nuclear reactor... ;)
@@bobd2659 I wouldn’t be doing anything like Injection Mold Design / Casting Mold/Lost Wax Casting Design / Intense Production Engineering (Assembly Lines+Large Scale Logistics and so on) etc, so that would save *SOME time*, and for ultra-basic machinesApplied Science etc have pulled that off with not as much dev time as some full on replicatable workhorse machine.
And granted it would be tedious,, and i would prefer not to use lead (supposedly Beryllium is a lesser, but still better than most, radiation shielding material), so shielding may require a bit of time, but honestly a mix of Room Interlocking (ie you must be 10 meters and a wall away before it can run), and just basic materials (huge pile of steel, etc) should work.
I’d imagine the majority of the work would go into Motion System Design (Probably similar to Existing Open Source Polar 3D Printers I’d Imagine) (Could Maybe Even Adapt “Open5x” for 5+ Degrees!), Tube+Sensor Choice/Calibration, and Firmware/Software (*Sorted that mess above by increasing complexity/time needed (in my armchair napkin math estimate) *)
@@ericlotze7724 One day build
I can truly relate to Adam’s love and excitement of “pealing back the curtain back on the world”. I do 3D LiDAR scanning/documentation to support engineering design. This allows my team to get into some amazing environments. Seeing the CT scan of the tubes is very interesting!
In the field of nuclear medicine these PMTs are used to detect gamma rays from an injection of a radioactive material into the body (Usually Tc99m). We are able to see where the nuclear isotope has traveled in the body thanks to these. They are constructed into a lattice and contained within a device called a gamma camera.
Ahhh.. vacuum tubes... The first radios I took apart had transistors, but the first radio I built in high school electronics had vacuum tubes. Thanks for taking me back Adam! BTW.. my first RF power amps as a design engineer were on ceramic substrates with through-hole PCBs. We were using SMDs a year later. Tech changes fast!!!
I think the photomultiplier is back to the medical imaging industry. The first CT scanners I worked on used them, but not like that one. However, although I never worked on them, I reckon that one would have been used in a "Gamma Camera". It would have been mounted in the 'head' with maybe a dozen similar tubes. Being hexagonal, they can 'nest' with at least six others and thus many more in the spaces available. In front of the array of tubes would be one or more crystals, sodium iodide if I recall.
As the Gamma particles from the patient - they are injected with a radioactive isotope - hit the sodium iodide, they interact with the molecules and the crystal emits photons. The photomultiplier amplifies the signal photons with a gain of probably 10,000 and generates a reasonable electronic signal directly proportional to the distribution of the isotope. From the array of PM Tubes, an image can be generated.
I believe the young man said modern solid state SCR's "were not made to handle this voltage and current." Well, maybe, maybe not. One of the CT's that I worked on (From the mid eighties into the nineties) used a solid state SCR to 'fire' the current the xray generator tank would use to apply across the xray tube. Up to 140Kv - 140,000 volts. The SCR wasn't switching that - it switched the primary current - but it was a huge ceramic device (same sort of stuff as a spark plug) that would audibly "tick" when it was fired! None of it is like that now, it all goes on in oil filled tanks rotating with the xray tube inside the scanner.
Very interesting--thanks for the back story!
this guy is AMAZING! please have him back on or to the cave!
Hi Adam I love your Chanel. I am in the uk and am disabled but you give me a chance to do things and learn things that I have never thought about. Absolutely brilliant . Thanks
Channel. Chanel sells perfume.
As an X-ray tech, this is such a fun video! Its cool to watch this while already having some understanding for the way the engineering and physics works for both the CT scanner and the photomultiplier tube.
Thanks! It's always interesting to hear from folks on the medical side of the CT world.
I read somewhere the thyratron was used as part of the ignition system in some WW2 bomber engines. The modern equivalent is the Silicon Controlled Rectifier, also known as a thyristor. I don't think that particular thyratron could carry 1000 amps continuously because the wires are far too thin. Instead it would be more of a current surge of 1000 amps, e.g. maybe for 100 milliseconds.
It was probably 10A nominal, less than 100A surge. No way it was ever rated for 1000A. Also it was probably in the 1500V-2000V range. I don't think he had a very good understanding of basic physics if he thought that sucker could pump out a kA.
Adam getting in touch with his Dr Evil side... Slowly building his giant laser! Would really like to see more of these videos please. Fascinating!
Absolutely fascinating. I never expected tube technology to be so sophisticated.
Thanks to Savage and Tested for sharing this type of content! I thoroughly enjoy watching videos about weird or niche electronics. I currently work in the high-power electronic industry. I’d really like to see more of these videos featured here. 🙂⚡️Thanks for bringing this one to us.
Fascinating episode, would love to see more collabs with them!
And a design implementation you didn't notice was that the photo-multiplier has a hexagonal "head", implying that many can be set up in an array.
you need to visit this place again with a truck load of stuff to scan ... would love to see inside so many things ... thx Adam
My wife bought me a Savage Industries shop apron for my birthday yesterday. What a beautiful piece of gear. It is so well thought out. Thanks Adam.
As a point of perspective for folks regarding how nutso the currents that Thyratron tube can handle are- 1,000 amps at 25,000 volts makes for 25 *megawatts.* For context on how insanely massive that number is, a typical US house with every single circuit drawing its rated maximum load will only pull in the neighborhood of 50 kilowatts- in other words, you'd need something like 500 houses all pulling as much power as they safely can just to max out that tube's capacity.
Is it a pure dual state switch or can it modulate the output?
@@MostlyPennyCat From what they said, it sounds like it's essentially an ultra-high voltage relay that can't be shut off without cutting power elsewhere. Truthfully, I don't entirely understand how that's useful, but it sounds like modulation might be possible?
@@HexagonaldonutIt works like an SCR. If used for phase control (like a light dimmer) when the AC waveform crosses zero (120 times per second in a 60 Hz system) the current stops. To use them in a DC to AC inverter, usually the output stage is arranged so turning on one tube interrupts the current in the one that is currently on, turning it off.
@@dale116dot7 Ooh, interesting! I figured there had to be more to it than was explained. Cool shit!
More like 25kw - 120v * 200A service = 24,000w or 24kw. And 200A service is kinda modern, a lot of older houses have 100A or even 80A service, so 10 to 12kw.. so 12,000w vs 25,000,000w
And thats why Doc almost has a heart attack when he hears 1.21 jiggawatts 😆.. 1.21 gigawatts is like 1,210,000,000w, meaning the flux capacitor is a tube 1000x more insane than the one shown
I love how excited Adam was even just to see and learn about the quote-unquote "boring" modern device
What would be cool would be large color prints of the image produced! That would sell like hot cakes! Thank you Adam and Scott!
My thoughts exactly! And they make very cool desktop wallpapers/background images :)
Adam, check out Glasslinger’s channel. A very skilled artisan with long form demonstrations of how these types of tube devices are made. The channel is a gold mine of obscure knowledge and techniques. I highly recommend. Cool video brother!
Fascinating it just amazes me how this stuff got figured out to get the job done and then the next task is to make it smaller. Probably the next step will be how small will the next requirement need to be before the quantum mechanics say nope you’ll need understand the physics that is currently unknown before you can go smaller or build it in another dimension.
Adam I'm going through and liking all your videos your a living legend, the work ethic on this channel is unbelievable
"Peel the curtain back on the world" is an elegant description of the scientific process!
It's so cool! @CuriousMarc grade stuff :)
Photomultipliers are still used in all kinds of analytic gear that use infrared, visible and ultraviolet light, mostly spectrometers, though CCD sensors are also used there.
Adam Savage...making all of us more enlightened and quizzically more aware of our surroundings.
Thyratron’s are awesome. Used them
In high power radars for the crowbar circuits.
Early night-vision scopes used 'channel plates' that exploited the photo-multiplier effect in an array of narrow, angled metal lines holes.
Each hole was sort of a continuous dynode, a voltage gradient across the thickness of the plate powered the thing.
Each channel made a pixel, which was projected onto a phosphor screen.
Awesome. Also-any relation to Steve Gallacci?
Ya know... I love seeing Adam have to ask a ton of questions to understand something he owns, but actually knows next to nothing about. It's a beautiful thing, the human mind. and those tubes. XD
Great exploration adam sir thanks for sharing another wonderful video.
The world is a glorious place!
Photon multipliers are also super essential in flow cytometry FYI 😁
Thyratron.
And it is indeed a high power switch, uses Townsend Discharge, which I believe is also the working principle behind the much cooler Mercury Rectifier.
You should definitely get one.
And then be very careful because they can kill you in multiple exciting ways.
Thanks for bringing in a couple of vacuum tubes for them to scan. Way back in the day I worked for Teledyne MEC (I'm talking around the late 70's) and wound the helix for thier traveling wave tubes. I was probably around 16 or 17 at the time and didn't really know what they were for and really still don't. But thanks for triggering those memories of my youth. It would be great to see one of those scanned.
The big neutrino telescopes still use PMTs (photo-multiplier tubes) for detecting very very low photon fluxes from the huge scintillator tanks they use for neutrino detection.
That's what I was thinking as well.
I too am fascinated by infrastructure. The basements, attics, steam tunnels, and mechanical rooms of the world fascinate me. I am so glad to hear of your interest in these, too!
I'm a guitarist, and we still actively use tubes in our amplifiers.
I was thinking just this - Not sure Adam has ever looked into it, but I think he would love the design aspects of classic hand wired amps both in the circuits (valves, transformers, etc) and cabinet design.
You can see the excitement in both of ‘em!
Stellar stuff! Very excited for the future of this technology
Vacuum tubes are awesome. Slowly accruing a collection of them myself...
Currently working on a Vacuum Tube Tesla Coil at this very moment!
Do u feel any pressure to collect them ?
I love this guy. :D
We're getting one of these at work in a few months, pretty excited
Do you know the price?
We're excited for you! Hope you enjoy lots of exploration with your Neptune scanner.
@@blindleader42 Neptune scanners start at $36k/year, which includes all the hardware, software, and service needed to operate it.
Adam there are still applications where tubes a still used in MRI machines and high powered radio transmitters also in high end Guitar and audio amps!
👍😎 Adam has the coolest “Just cuz it’s cool” stuff
This is awesome. I've been getting into tubes lately and want to make a tube amp for my turntable as a DIY project. Tubes are so much cooler than solid state parts.
fascinating interogation of two rare and fascinating devices! thxu
With two rare and fascinating people
Just realized I have one of those old Thyratrons at home! Cool !
Unexpectedly fascinating.
Reverse-clickbait title, I was expecting a box of radio/TV tubes, but you had two really interesting specialized tubes!
That was quite interesting. Thanks Adam!
This was absolutely fascinating!!!!!
"Scientific glass blower". Now that's as wizardly a real job as I've ever heard.
I know right? I wanted to get into glass blowing when I was younger, didn't happen but hearing that term makes me go 😵🧐
It amazes me the shere brilliance involved in Early electric equipment
I can only imagine the thought processes that were part of designing such a device, and to generate its own hydrogen! Just part science part alchemy and a little wizardry. Awesom😅
That EEV CX-1538 thyratron was a bespoke part for the LLNL Advanced Test Accelerator. It was developed and tested to handle peak currents in excess of 10,000 amps, although was put into operation at only 2,500.
Six were used together in a chassis to switch a capacitor charged to 25kV into a 1:10 transformer to charge a Blumlein to 250 kilovolts, which was in turn switched by a gas-blown spark gap into an accelerator cavity to deliver 250keV acceleration over a 70 nanosecond pulse. Such modules were stacked 190 deep for a 50MeV electron beam.
I want to make a small chemistry comment! Hydrogen is _in most cases_ less of an escape artist than Helium is, because most hydrogen gas we encounter is the dihydrogen molecule. Because quantum physics, it's hard to exactly compare the sizes of atoms and molecules (they require different metrics, thus making it hard to compare), but in pretty much every case helium is **smaller** than dihydrogen, by a pretty significant factor I believe. Of course, hydrogen is still a crazy escape artist, but it can't quite beat helium.
(Cases where we don't see hydrogen as dihydrogen include in space! Most of the hydrogen in the universe is, in fact, monoatomic hydrogen, but Earth is our special case home.)
I believe you're right.
I was thinking that at high enough temperatures (excluding plasmas) might separate into individual hydrogen atoms. I can't seem to find if that's true.
Buuuut... looking at the Wikipedia article, it appears the thyratron operates by the hydrogen being turned into a plasma. I'd suspect a proton is a pretty good escape artist in this case, even better than helium.
I understand about 40% of the words these two nerds are saying but I could listen to it all day.
Here's a 21st century sentence. "After the wonderful work they did scanning my robotic bird, I decided to get my space tube looked at "
If you ever get a chance you should go to the race if gentlemen I think you would love seeing very old technology being cared for and used
It’s amazing to see technology shrink down like this. Maybe someday a CT scanner will be a thing anyone can buy, and this is a neat step in that direction.
Thyratrons are used a lot in our old radar systems here where I work.
This episode blew my mind
When you talk about the development of the thiotron: the math, the schematics, the failed attempts.... I'm immediately thinking of the huge breadboard that incorporated all the elements of this device and the tests that caused changes to the breadboard, until they had a working model. Then the iterations of reducing it in size to fit in a smaller package.
I was like the DiCaprio pointing meme at the beginning when they showed the crates and I was like "OH ShockWatch stickers!" pointing at the screen.
I have an extensive collection of specialty vaccum tubes, if you want to show more on the channel I can help with that.
Some highlights as Wanderfeldröhren by Siemens (used for satelite transmissions), photomultipliers, TV camera tubes and the elusive lorentz Napfröhren.
You put a scintillator material on the front of the photo multiplier to detect certain types of radiation. The chemical releases photons when the radiation hits it and the PM detects the photons.
Scott explains science stuff to a maker. Also he x-rays the stuff.
Two nerds, nerding. I love this shit. So much passion in one video.
This is incredible!!!
congratulations!!
I love vacuum tubes!!
Adam your amazing at blowing minds. Poof. Brain is on fire. So cool.
There are Thyristors (SCR) that can handle 6 kV and 100,000A. They can be put in series and run at voltages like the thyratron.
I worked for a company in the UK that maufactures photomultipliers. Electron Tubes is now a subsiduary of Ludlum Measurements Inc.. At one time RCA was a leading manufacturer, as well as Phillips and Hamamatsu in Japan.
Electrons are "generated" by the photon or photons interacting with an electron emmisive layer, the photocathode, which is deposited on the inside of the front window when the photomultipler is made. Electrons are "knocked" out of this layer and electrostatically focused, as stated here, onto the dynode stack. Each dynode is held at a higher potential than the preceding one. This "attracts" the electrons and focuses them, by the electrostatic field generated, guiding them down the stack. At 5:37 in the video, to the right of the end of the glass envelope inside the spring, you can see what is probably a chain of resistors, on a PCB, which is used to generate the voltages required. There can also be other electonics on this PCB which may be used to condition the output signal.
To detect photons that would be blocked by normal glass, in the UV part of the spectrum, the front window can be made from quartz or so called solar blind ones using magnesium fluoride.
Different photocathodes are used to enhance the photomultipliers sensitivity in the IR, visible and UV parts of the spectrum. Again at 5:37 in the video, just below the dynode stack, you can see the slightly blurry shapes of the "generators" which contain the chemicals that the photocathode is created from during the "processing" of the tube.
A great deal of mechanical engineering, glass processing technology and sophisticated chemistry goes into making a photomultiplier.
Photomultiplers are still used extensively in the particle and high energy physics fields as well as astronomy, pollution monitoring, process control and medical physics, to name but a few.
Science: “Pay no attention to that man behind the curtain”.
Savage: “Help me pull this curtain back”.
Photomultiplier: _ehm_
CTscanner: *owh you are my ancestors, sir. Please come. Sit down here, please and make yourself comfort*
You should sell those scans as prints.
PMTs(Photomultiplier Tubes) are used in Medical Imaging Devices. Like a Gamma Camera. I have calibrated the gains on them
adam you know you have to make a high voltage pulse lazer now i hope Lol :D
The Philips photomultiplier tube is used in nuclear medicine. It detects faint flashes of light emitted by a gamma particle as it passes through a crystal. Usually about 50-60 of those photo multiplier tubes (PMT's) are situated in a large detector to capture gamma radiation emmited by radio isotope injected patients. Then a computer uses that data to create a 3D image of anatomy in question.
Amazing stuff.
There aren't many devices that still use photomultiplier tubes nowadays. I'm sure there probably are spacefaring applications for these things, but chances are pretty good that this one was used in nuclear medicine. I reckon it might have come from a gamma camera or a SPECT or PET scanner, which Philips does actually make.
Just in case you're wondering what nuclear medicine is, it's very similar to radiology, the difference being that radioactive tracers are administered to the patient and the scanners themselves don't emit radiation, whereas in radiology, a CT scanner fires X-rays through the patient and looks at what comes out of the other end.
Adam: if you ever get a chance to do that again, could you have him scan a klystron and explain to me how that works?
Because its the closest thing to dark magic in a radio amplifier to me.
Many of the only klystrons in the world are owned and operated by NASA JPL, and are very fascinating devices! An overly simplified (and somewhat incorrect) explanation of their workings is a super high power microwave oven, but it focuses light (radiation) rather than cooking with it. I don’t recommend you stand near one when it powers on.
@@GearsAndBricks
I don't know if they still are, but they *were* one of the last stages of UHF television transmission.
When I first started looking into the processes of television transmission, I ran across the term, looked up the device, and was kinda blown away by how they look.
Oh yeah! I forgot about the television industry! 😂 Yes, they were (and still are) used everywhere. It’s difficult to find information about klystrons, though. I work in the industry, yet I don’t know everything i’d like to know… 😅
@@GearsAndBricks
I just leaned what a Gunn diode is, and the difference in size blows my mind.
That came straight off the DeLorean Time Machine - 1000 Amps? It must have been the switching mechanism for the flux capacitor!
Love these