Interestingly just within the past few years, a few small scale gem cutters and dealers have realized that the companies making this material have failed boules and offcuts that they will sell very cheaply which can be turned into highly unique jewelry with stupendous qualities of ultra bright fluorescence, extreme color play due to high index of refraction, and incredibly long lived (many hours) phosphorescence. Specifically House of sylas and Angry Turtle Jewelry in the US are essentially creating a whole new market around synthetic crystal jewelry usually involving things like BGO, lutetium-yttrium oxyorthosilicate, and lutetium aluminum garnet. If you search for these terms or their names on social media you can see examples of some really fantastic material they're making.

@gus473

Жыл бұрын

My wife has a set of earrings made of less-than-perfect ruled diffraction gratings, which have drawn many compliments over the years. Not commercially available, sadly.... 😎✌️

@gree9963

Жыл бұрын

hOPEFULLY CHINA INVADES TAIWAN AND us NUKE tsmc😂😂😂😂😂😂

@williamchamberlain2263

Жыл бұрын

Awesome

@liesdamnlies3372

Жыл бұрын

So…some day one could have a gemstone on a necklace or bracelet or something as a crude radiation detector…

@Peter_S_

Жыл бұрын

@@liesdamnlies3372 Yes, think of that item as an oven thermometer to tell you when your goose has already been cooked. The photomultipliers they're typically attached to have an amplification factor of something huge like 100,000 and they are looking for single photons so don't expect your eyes to have similar sensitivity. Side note: if you power up a photomultiplier tube in room-light, you'll cook it.

From Wagyu beef to scintillation crystals for PET scanners. Jon, you never fail to amaze. Thanks for the video.

@fredfred2363

Жыл бұрын

Yep. 100% agreed. 👍🏻😀🇬🇧

@zorintoto1167

Жыл бұрын

Thank you for reminding me I need to buy steak for today

"a long decay time is like a slow refresh time on a TV." wow.... You really had faith in how nerdy we are with that analogy....

A couple minor details to note. When one of those 511 keV gamma rays undergoes photoelectric absorption in the crystal, the gamma ray disappears and all of its energy gets put into the photo-electron. On the other hand, you have another phenomenon that can occur called Compton scatter, where the gamma ray does bounce off with lower energy, but having given some of its energy to an electron. Both of these processes occur in scintillators, with Compton scatter becoming more important for lighter elements and higher energy gamma rays. Second, the valence band of a scintillator is all full up of electrons. When an electron is excited out of the valence band, it leaves behind a missing electron (called a "hole") in the valence band. The hole acts like a particle, in that it can move around and carry charge (although as you might expect from something that is a missing electron, it carries positive, not negative, charge). In order to generate scintillation light, the conduction electron can't just fall back to the valence band anywhere, because as mentioned the valence band is all filled up and there's nowhere for the electron to go. Instead, the conduction electron needs to find a valence hole, so there is a place for it to fall down in to. When it does encounter a hole, it can emit a scintillation photon as the conduction electron and valence hole recombine.

@chalkchalkson5639

Жыл бұрын

also: you often get multiple excitations per photons, that's why some systems even add additional WLS crystals to convert the blue LYSO light to green for better detection (eg that insane CERN ToF PET project using axial instead of radial scintilators)

@janami-dharmam

Жыл бұрын

what is the band gap for these crystals? Recombination need not be slow but the shape of the fermi band is going to be critical. What are the crystal structures of these compounds?

@coffeeaddict8972

Жыл бұрын

Also I think there is one more condition a scintillation crystal has to fulfill and that is high light transmission. It needs to be as transparent as possible basically so the light can get to the PMT or Si detector without much attenuation or scattering.

@TheRadconranger

Жыл бұрын

same theory on why scintillation detectors work...Are you a Health Physics Tech or specialist by any chance? You sound like a bored HP tech explaining detector theory to a junior....;-)

@lukecampbell6647

Жыл бұрын

@@TheRadconranger I'm a physicist that has worked for more than a decade now in the field of radiation detection and material science (usually material science as applies to the electronic excitations from radiation detection). My thesis work was looking at the electronic excitations in condensed matter which you get from x-ray absorption. I work at a U.S. national lab (PNNL) where we worry about things like detecting smuggled nuclear material, scanning spent nuclear fuel, building new x-ray machines for emergency response or airline security, and other stuff where detecting high energy radiation is rather useful. Obligatory disclaimer - in this reply, I am speaking as a private citizen and not in any official capacity on behalf of PNNL.

I have a gigantic version of those crystals sitting on my desk right now. Found the whole detector in the trash a few years ago. The PM tube is also still somewhere downstairs in my workshop

@fjs1111

Жыл бұрын

Those crystals come in handy and are fairly expensive.. Don't lose it! :-)

@Muonium1

Жыл бұрын

Do you know the exact crystal composition?

@gus473

Жыл бұрын

Betting that it's a Hamamatsu PMT! 😎✌️

@fjs1111

Жыл бұрын

@@gus473 Yes! They make the best PMs, Scintillators and Scintillator based detectors. I think they have silicon detectors too. They used gallium a lot I think.

@Danji_Coppersmoke

Жыл бұрын

Will be handy when Orcs invade your house.

It's worth mentioning that a pair of photons emitted during during a positron/electron annihilation travel away from the point of the annihilation at exactly 180 degrees. The system detects each pair of photons as a 'coincidence', allowing the system to reconstruct a straight line between the two scintillations that were detected. More advanced systems also process 'time of flight', whereby a tiny delay between the detected scintillations indicates the position along the straight line that the annihilation took place. Sorry if I'm boring you, but I found this relevant since other nuclear medicine tracers such as TC99m or I131 don't exhibit this unique property.

@mvadu

Жыл бұрын

You are not boring, but adding very important additional information to the topic covered in the video.

@luipaardprint

Жыл бұрын

Yes, you actually answered the one question I was still wondering about.

@chalkchalkson5639

Жыл бұрын

aktschualllllly it's not exactly 180° since the position is usually moving during annihilation, lorentz transforming back gives you slightly less than 180° and introduces an error source

@Tuttle9955i

Жыл бұрын

@@chalkchalkson5639 very hiiinterestin' thanks 👍

At 4:30, "visible" is irrelevant since photomultiplier tubes (and NOT our eyes) detect the flashes. However, the photon given off by electron-hole recombination has enough energy to excite another valence electron into the conduction band. Thus, the scintillator crystal is opaque to these photons and that is why we dope the crystal with thallium. Eventually, a conduction band electron will excite a thallium atom. Since thallium emits at a slightly lower energy, these photons can no longer excite the crystal and the crystal is transparent to them allowing these photons to reach the photomultiplier tube.

I went to a factory in the US that grew them. Two independent power companies supplied the site, and they had this ginormous UPS. Why? Because an interruption to the power would interrupt the crystal growth and would ruin a whole batch. The guy handed me a crystal - it looked like glass but weighed like steel. "Careful! That's worth like a BMW." You should also see the wiring inside a PET scanner. Truly amazing technology.

@codyhufstetler643

Жыл бұрын

I work in scintillator manufacturing. Not sure if that was our facility, though, our power flickers far too often 🙄 we do have a gigantic UPS and a massive natural gas generator though to keep the furnaces running for that reason. I heard once of a research facility that was growing extremely sensitive crystals that would be ruined by even the brief interruption before the generator kicked in, and it had a giant flywheel that would keep everything running just long enough to bridge the gap until the generator kicked in.

One driver for fast and bright scintillators is time-of-flight PET with coincidence time resolutions below 500ps. This was what LSO/LYSO scintillator made possible, as they produce enough photons in the beginning of the light pulse to enable this time resolution (LaBr would be another candidate, albeit with higher scatter fraction). It would be a topic on its own, but it may be interesting to mention the recent transition from photomultiplier tubes to silicon photomultipliers, and the "10ps PET challenge".

@crackwitz

Жыл бұрын

since 500 ns at light speed (time of flight) is 150 meters, I'm guessing you meant to write "500 ps", which means 0.15 meters. 10 ps give 3 millimeters.

@thomasfrach413

Жыл бұрын

@@crackwitz yes, I meant 500ps not ns 🙂 CRT of 10ps would potentially eliminate the need for reconstruction as the voxel size is in the order of 3mm, though that depends on system setting and application.

@Fulcanelli88

11 ай бұрын

La Br ? No endeed

You should do CT scanners and MRIs next! I was born with Osteogenesis Imperfecta or brittle bones and I can’t tell you how many countless MRIs and CTs I’ve had in my day. Super interesting 10/10 as always buddy ❤

damn son i gotta give it to you , you got a big nation level of motivation to make complex video in a short time , hat off brother :d .

@subliminalvibes

Жыл бұрын

He's a machine, and yet he sounds like a freshman!

Your work here on explaining crystals is unparalleled.

Our engineers were so excited by the availability of LSO:CE and LYSO:CE for the SPECT cameras we made. Giddy is the word.

Great video! Small correction, your images of yttrium lutetium and cerium say they have a melting point of 2,400c while you say they have a melting point of 24,000c. This might be confusing for people who are only listening to the video.

@41chemist19

Жыл бұрын

@Bigga Nigga I'm not making fun of him. I really do appreciate his work but if there're informational inaccuracies it's worth mentioning.

@htomerif

Жыл бұрын

@@41chemist19 I was gonna mention it if you didn't. People get stuff like this wrong all the time in presentations and generally you want to hear about it sooner rather than later. I corrected a professional chemist who kept mistakenly saying "glyphosphate" instead of "glyphosate" and that kind of correction is just a matter of professional courtesy. Letting it go without commenting on it would be disrespectful. Letting it go is basically saying "you're not smart enough to ever get this right so why bother correcting you?"

@ericcarabetta1161

Жыл бұрын

Nah, pretty sure it's 24,000℉. 😏

@ricktao8

Жыл бұрын

According to wiki lutetium oxide, the melting point is 2,400c as shown in photo. So when in doubt, check google wiki.

@htomerif

Жыл бұрын

@@ricktao8 Nothing has a melting point above 10kC, so you really don't have to bother checking.

You can also find scintillation crystals in xray equipment. Some facilities that are older or in poorer areas use computed radiography, which was developed due to its ability to easily obtain a digital image with minimal changes to a older traditional film systems making it a cheap upgrade. You fire the x ray beam through a target and when the beam reaches a phosphor layer to store some of the energy. They the shine a laser on it one row at a time which releases the stored energy as visible light. They then have a photodetector to read the signal and construct the image. You also see it in some fully digital xray radiography systems and CT scanners. Where the xrays are converted into visible light and the signal is captured with photodiode on an amorphous selenium or silicon layer. There is also direct detection as well there they measure liberated charge inside a substance but could require higher radiation dose because of the weaker signal from this method.

@benmcreynolds8581

Жыл бұрын

That's the method they used when they diagnosed me with Gastroparesis and imaged my digestion after I ate a meal of radioactive scrambled eggs and slice of bread.

@chalkchalkson5639

Жыл бұрын

Other neat applications: detectors in astronomy and particle physics and for tissue equivalent dosimeters. PMMA is a scinitlator (though a bad one) and happens to interact with xrays very similarly to water. So you can readings for radiation doses that require a little less guesswork/conversion to convert them to the dose which tissue would receive.

FYI: if you want to see scintillation (and check the UV absorption of your windows), get a gatorade bottle safely plastic seal: in sunlight it will emit bright violet light out of the sides: that is UV converted to visible via scintillation. Works best on a low-cloud day. You can also put tonic water in a black light, it will glow blue...same color as Froto's sword.

@karhukivi

11 ай бұрын

That is fluorescence, not scintillation. If you want to see scintillation, look at the luminous hands of an old radioactive watch with a strong lens, you will see the individual scintillations of the alpha particles striking the phosphor.

@DrDeuteron

11 ай бұрын

@@karhukivi where I’m from scintillation is fluorescence, and phosphorescence is delayed fluorescence, unless it is microwaves, then scintillation is speckle noise

@karhukivi

11 ай бұрын

@@DrDeuteron Most scintillators will also fluoresce . But if for example you have a ZnS screen and bombard it with alpha particles, there will be a succession of flashes which translate into pulses in a PMT. I would not consider that as fluorescence. A bit like the distinctions between killing, murder and dying, it depends on the circumstances!

@christopherleubner6633

9 ай бұрын

Yup the dye us the same one used for scintillating plastic, but it is generally used with acrylic for purpose made scintillating wands.

I was disappointed to learn that if I undergo a PET scan or radiation for cancer treatment, I don't get a t-shirt saying "I've been irradiated. Where's my superpower?"

@heptex8989

Жыл бұрын

I see a golden opportunity to dominate the PET market

@monad_tcp

Жыл бұрын

that's because you were already irradiated and are being irradiated always everywhere all the time

Something that baffled me for years is why does the plastic wrapper around the mouthpiece of Gatorade bottles glow a strange purple color sometimes. I'm not 100% this is the reason, but recently I discovered scintillators and I believe that's the reason behind the glow. Some plastics have scintillator properties, and that would explain why the plastic only had the strange purple hue when in sunlight.

@alexcarter8807

Жыл бұрын

All kinds of routine shit can be used as a scintillator. It's just that the exotic stuff works better.

@janami-dharmam

Жыл бұрын

most common plastics will not fluoresce, they may be doped with some fluorescent dyes.

@additivealex4566

Жыл бұрын

@@janami-dharmam PEN(polyethylene napthalate). On the wiki for scintillators there's a picture of extruded plastic glowing the exact color I've seen on the Gatorade bottle wrapper.

@Tadesan

Жыл бұрын

They put dye in the wrapper so they can easily see that each package has had that wrapper put on it.

@additivealex4566

Жыл бұрын

@@Tadesan interesting. Do you have a source? I haven't had Gatorade in a while but I distinctly remember only glowing purple/blue in sunlight

I work with these crystals on a daily basis. The only thing I noted that wasn't really accurate is that organic scintillators (at least the ones we make) aren't really crystals. They're a plastic with a scintillating dye. The density/detection efficiency is pretty low, but the plastic is cheap, so you can make huge panels of the stuff to monitor huge areas for radiation. You can also do plastic stuff with it, like pull it into fiber optics. The fibers are actually really cool if you get them in the wave shifting variety. Wave shifting is like low energy scintillation, and is really just fluorescence. But when you put that in a fiber optic, light passing through is absorbed and re-emitted in a random direction, and some portion gets trapped in the fiber. Get a significant length of fiber all trapping light, and you get a mysterious string that glows on the ends.

Thank you, your unique perspective is always refreshing given my lack of "pure" academic discipline. I am more of a complex eclectic type of observationalist, so&/thus, scattered information sometimes feels most organized and "pleasing" to me.

Wow this is insane. I'm a researcher for PET and at 7.53 seconds, this PET scanner is the JPET. It is design as plastic scintillators rather than crystal (reduce cost and easier to work with) and because of that the dominant interaction is Compton scatter, at the density for plastic, and so they needed multiple layers of the plastic scintillators for it to increase the sensitivity (fraction of gamma photon detected to gamma photon emitted). The image shown at 7.53 s is of the first generation prototype where it is using the photomultiplier tubes with lots of gaps between scintillators while the second generation has less and smaller gaps and uses SiPM modules. The most insane part is that I was there for a conference meeting in Krakow at the end of April and they showed everyone around the labs and of these prototype scanners. Now I see it on a video of someone I subscribed to on YT.

It is super cool to hear someone else talking about these things! Really nice coverage too--I only get to make ultra short videos but there is so much more to tell about these things. I feel like the story of having to develop an entire market and processing pipeline for lutetium so they could make enough LSO could make its own miniseries.

This deer knows so much about everything.

Photomultiplier tubes, CHEAP !? Boy, times have changed !

I love your stuff. I work in semis so got drawn in for that but lately i enjoy the other topics.

11:41 perks of playing Geoguessr: seeing that black/yellow spiral warning pattern on a utility pole and immediately thinking that's Taiwan! (If the lines were straight vertical, it would be Japan. If spiral but positioned over the ground, South Korea. If no warning pattern but pictures of the Dear Leader everywhere, North Korea.)

Remember finding a PET scanner at s junk yard that had the 4 section square PMT tubes and the BGO scintillating crystals. You can change the resistors on the end and make a position sensitive radiation detector with one.

I didn't know that I would find PET Scanners so interesting, Jon. Thanks!

I wasn't aware of the need of a glowing crystal to scan my pet.

Great video! I’m an EE student at Stanford, and your interesting content really complement my courses :)

Very happy the topic ended up working out for a video! After your polite email response and no content on it for so long I assumed it was deemed not a good fit :D 6:59 3D PET is probably supposed to refer to ToF PET here? PET is pretty much always reconstructed in 3D, that's why you typically limit yourself to coincidence measurements where both 511keV photons are detected.

you overlooked a major problem in PET scanners: higher resolution sensors don't create higher resolution images. the resolution is already now limited by the random time the positron takes to recombine with an electron!

What an awesome episode, great work, super interesting👍🏻👍🏻👍🏻

Because nothing ever went wrong with ominously glowing crystals

You can get some of those crystals as jewlery, combine it with a UV laser, and it'll glow for a while. Wish they were resistant to wear...

@AngryTurtleGems

Жыл бұрын

LYSO/LSO are definitely on the soft side, but fortunately other scintillators like Ce:YAG, GAGG and LuAG are all pretty durable and can even work as ring stones.

Just one quick comment, the term "aromatic" when talking about organic scintillator crystals doesn't mean they're smelly. It's a chemical property involving the electrons in certain ring structures (pi electrons in resonance). Admittedly, many of the first studied aromatic compounds (benzene for example) did have distinct odors, but as a general term its not a requirement.

Very interesting subject ! Thanks a lot. 👍🏻🙏🏻

Making the most boring sounding topics sound interesting is a unique specialty of yours isn't it?

@TimPerfetto

Жыл бұрын

Ohh yes I appreciate you saying so

@answerman9933

Жыл бұрын

I am always surprised when I actually finding interests in some of the eclectic topics.

Enlightening. Exellent informative video plugging a hole in my knowledge. Thank you! 👍🏻😀🇬🇧

Thank you 👍

I don't know how you do it but you make topics that I found boring interesting

I don't like the idea of positrons annihilating my electrons.

@user-hu2iw5qu3i

Жыл бұрын

If you must have a PET scan made this is the least of your problems...

It seems like there could be some interesting Laser applications with something like LuAG instead of YAG.

To get a higher spatial resolution, SiPMs are the way to go. They're very cheap compared to regular PMTs, but the measurement equipment to get a signal out of a large array is very expensive. My lab wanted a 12" diameter array of SiPMs but the cost would be at least in the tens of thousands of dollars.

It would have been interesting to mention how much a PET scanner costs. Do a video about CT scanners, especially the new photon counting scanners!

@janami-dharmam

Жыл бұрын

The dye (glucose containing a radioactive fluorine) must be made freshly in a nuclear reaction and costs a lot (for the user). In India, GE dominates these markets and the price is a closely guarded secret.

"…the less likely we are to get Spiderman" That's effing brilliant!

You ain’t scanning my dog in there! 😊❤

@unitedfront9717

Жыл бұрын

Yes because i will be eating it

@monad_tcp

Жыл бұрын

@@unitedfront9717 the dog, or the scintillator ?

@unitedfront9717

Жыл бұрын

@@monad_tcp both

@maeanderdev

Жыл бұрын

And no Commodore neither

Thanks!

@TimPerfetto

Жыл бұрын

How disgusting.

@heptex8989

Жыл бұрын

​@@TimPerfetto it's ten dollars lmfao

@TimPerfetto

Жыл бұрын

@@heptex8989 Oooohhh

@heptex8989

Жыл бұрын

@@TimPerfetto assuming you are up there on the autism spectrum

Scintillating topic to be sure! Sometimes I get so excited that I wonder if I emit a photon before dropping to a lower energy state.

Asianometry, your accent is so good it makes me forget that English is not your probable first language. When reading, 2400, twenty four hundred, is not twenty four thousand.

Have you done image intensifier tubes? I only have a half-assed understanding of their history and manufacturing but it seems interesting in the same general sense as these crystals. (specifically the MCP that makes modern night vision possible. The rest of it is pretty much just a CRT)

@janami-dharmam

Жыл бұрын

theoretically you can consider a MCP as an array of thousands of PMTs with micron sized windows and electron amplification of about 100.

@htomerif

Жыл бұрын

@@janami-dharmam Yeah, I know how they work, but how they're manufactured would be interesting. It might not be quite as easy to research though. My rough understanding is that the MCP starts off as a bundle of tubes that is stretched and folded a bunch of times like taffy, then sliced into wafers. I have no idea how the structure of it survives being cut up though.

@janami-dharmam

Жыл бұрын

@@htomerif that is more or less the common process.

Could you do a video on EELS? Or perhaps on TEM in general

Asianometry: "have you ever done a PET scan?" My Brain: "doesn't have to be a PET scan"

Its called pet scanner, but it is HUGE

24 hundred 👍👍 Dunno how you get so many great essays out on such a regular basis. Maximum Effort! lolz

this just made me not to want to get that pet scan on my gallbladder more

I thought PET scan is just a pet that scans you... like how a cat scan is when a cat looks at you and scans you.

Thank Youu

BTW, using E=MC^2 works well to calculate the energies of those two anti-parallel gamma photos. It's a good exercise. There are TWO photos created because the net momentum must also be brought to zero by two photos moving in opposite directions.

@DrDeuteron

Жыл бұрын

don't forget ortho-positronium's 3-gamma decay.

@SF-fb6lv

Жыл бұрын

@@DrDeuteron So for 3 gamma photons, each gamma photon energy is 1022 KeV/3 and 120 degrees apart?

@DrDeuteron

Жыл бұрын

@@SF-fb6lv no, it’s all about phase space, like in beta decay.

@SF-fb6lv

Жыл бұрын

@@DrDeuteronNow I get what you mean by your very compact response. But I had to research it a little...

I've gone through a PET scan due to a cancerous tumor. Interesting technology.

I have worked in medical image (DICOM) processing software for years but i did not know about PET, only the calssical modalites like CT or MRT. So this machine is basically an Antimatter-Gun firing anti-electrons?

It's the day of exams for me and part of it is based on gamma scintillators and PET scans so this video couldn't have come out at a better time.

So basically we've figured out a way to scan human tissue using antimatter.

Well, literally scintillation means sparkling, because in Latin and then Italian "scintilla" means spark. It seems that it has a common etymology with shine.

I have the second sight i know excatly what next weeks topic will be: 'The failure of the terranian lightsabre-industry and why corrosant is dominating the market'

"don't go easily into that hot hot melt" LOL... hopefully I wasn't the only one to catch that.

So the lyso crystals are just used to measure annihilation photons? And the natural radioactivity of lutetium doesn’t throw it off

Did gamma rays turn Bruce Banner into the Hulk?

10:16 I though that was *the matrix* method... Oh... wrong -skis

So.... due to TSA's involvement we have better scanners? Talk about under funding medicine.

@ssl3546

Жыл бұрын

well with Japan's declining population there are fewer and fewer Tomokos around, hence less need for tomographs

@monad_tcp

Жыл бұрын

didn't you see what happened in 2020 just because 5% of the population had to go to the hospital at the same time ? imagine if it was higher than that, under funded is selling it short, its way more underfunded than that

11:53 why isn’t there a real photo of Yttrium(lll) oxide as there is for the other two oxide ingredients?

I am endlessly fascinated with MRI machines. I’ve had a dozen or more MRI scans due to my arthritis. I had NO idea that a PET scanner was that different! That was a fascinating episode, thanks so much. It is wild to me that chemical scientists can create so many different compounds of materials.

We had one of the first PET at BNL,NY national lab DOE that did addiction research in early 90s. Dr Nora Volkow found addiction was inherited not a behavior.

@DrDeuteron

Жыл бұрын

In the nuclear physics community, the down side of doing an experiment at BNL is getting Lyme's disease.

@MitzvosGolem1

Жыл бұрын

@@DrDeuteron I have the red meat allergy from a lone star tick bite from that area. I grew up near bye. Before 1980 very few issues with ticks and Lyme disease. We rode dirt bikes all day in surrounding forest rarely got a tick bite. Today I would not set foot in woods or fields unless covered in permethrin. Kindly read "Lab257, history of Plum Island"( non fiction) . Information shows where this terrible disease came from and why federal government refuses to admit responsibility and help the infected people. Half the people I know have it on Eastern long island new york.

@11:59 That is (like you said it 😄) a controversial statement, as the temperate scale doesn't start at 0°C. It's about 3.5x starting from 0K.

@DrDeuteron

Жыл бұрын

or 0 degrees R

you dont miss

Very interesting

Have you missed or ignored GE(Li) and pure Germanium detectors or you were specifically dealing with PET ?

Now make a video about BAK4 prism and ED glass

the future, literally, *glows in the dark*

I know it's going to be good 👍

A bit nit-picking I know, but 511 KeV radiation is not "high-energy" gamma radiation, rather it is on the low end of the gamma radiation range of 300 to 3000 KeV.

Did you say iridium metal crucibles? No wonder these crystals are so expensive.

You skipped the organic scintillators completely; they are low in density but great in performance. Even the lowly naphthalene (very cheap and easy to make a single crystal) can show good fluoresence (if my memory serves me right)

@DrDeuteron

Жыл бұрын

tonic water works well, too.

I've never heard vrom something like this. Thank you for giving me a look inside a, otherwise undetectable, world of technology. Thank you! (not native speaker, sorry)

11:49 - "Three of them .... melt at TWENTY FOUR THOUSAND DEGREES OF CELSIUS" - ??! Rather, "24 HUNDRED °C" or 2400°C (as CC reads).

Can you do ultrasound please?

I just got some scintillation crystals from china to make an xray spectrometer. How timely.

You said 24,000°C. You meant 2400. Also that’s still way hotter than the surface of Venus, which is around 475°C.

i want a lighsaber, it's an elegant weapon, for an elegant age 😀

Wizards LOVE collecting crystals 😎🔮🔮🔮🪄

10:53 Why can't I summon corpeal Patronus with that spell ? professor

Great

Anytime there is a DBZ reference is a WIN ;)

I asked my buddy who was a trash man why there are the radiation detectors when you check in at the dump. I thought maybe smoke detectors but he said the main thing that set it off were bags of poop from people that were injected with this stuff.

So a PET scanner is just a backwards diodes pumped laser?

@Peter_S_

Жыл бұрын

Interesting perspective. As with the comparison between a Vidicon camera tube and a CRT, many converse analogies do apply.

Shadow wizard money gang crystals

Valeu!

One also must smudge them with sage 😅

So the difference between a scientist and a hippie is...

So at 11:57 you said 24000°C but the screen says 2400°C. That's obvious. But then you say it's five times the temperature on Venus. If you measure it in Celsius, it seems correct. But absolute Celsius cannot meaningfully be multiplied because its zero point is arbitrary. So better to use Kelvin then in which case is about 3.5 times, not 5. To be clear, when using Fahrenheit you get a different multiplier than Celsius because its zero point is just as arbitrary as Celsius. Five times as hot only has meaning when measured from zero heat. It's like saying a 6 foot table is twice as long as a 5 foot one, but you don't measure the first 4 feet. A table that's twice as long as another is that in any measurement, feet, thumbs, arms-lengths, miles, etc. In Celsius you don't measure the first 273°C (which is °K, when used relatively, since one °C is as big as one °K).

@jurian0101

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↑ This (One does not simply divide or multiply degrees °C. ) However.... if it happens we're talking about the temperature for nuclear fusion, some millions of *degrees* the units don't matter very much, since 273.15 is rounding error here, while Celsius and Fahrenheit differ by 9/5 which is less than an order of magnitude. 😛