Cherenkov Effect and Radio

[Lauri-CoyoteFrostbite]

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Very early on, back when I fell in love with physics- a kindly undergrad professor told me

"Lauri, there are two types of physicists- the Applied, and the Theoretical."
"You, little Pilgrim, are the Applied"

In other words, he was kindly telling me I was no Einstein. And just as well- those guys are on another astral plane- they can Grock it but not apply it. That's where the Lauri's come in.
We are the ones with the screwdrivers.

So saying, trying desperately to rein in this topic by doing something 'applied' and getting away from the theoretical -- here is an introduction to Cherenkov Radiation -

Cherenkov Radiation & Neutrino Detection - ppt video online download

Its less than six minutes long. Ever wonder if HAL 9000 (2001: A Space Odyssey) had a sister?
Well, the answer is Yes, he did; and she works for the University of Mississippi as an applied physicist-- she read that above monograph.

_________________________________________________


Okay, so we are on a roll -- here is one of the best simulated movie scenes involving Cherenkov Radiation I can think of. It sends a chill up my spine each time I see it, for the lab building still exists-- and I have stood in there, exactly where Louis Slotin did this experiment real life.
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Lauri
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[MUTNAV]

Great, you posted the video while my comment was in moderation about the demon core... The question remains though. Why blue. and why did the NY transformer glow blue (some people say it was from the copper, but I don't really believe that)... I've been hit with a nice bright flash as a kid while trying to make hydrogen and oxygen by plugging bare copper wires into an outlet. (the DC power supply I had been using just wasn't making the H and O2 fast enough). and when the flash took out about two inches of copper wire, it wasn't blue, it was a nice broad spectrum white.

Another question is what material would have a the natural resonance frequency around 222 Mhz, I think Hydrogen is in the low VHF range (maybe 46 Mhz or something), there used to be a chart in a physics book that covered things like that.
If I'm really even thinking about the right things, I might be misunderstanding all of this completely.

Thank you so much for bringing this topic up to begin with.
Joel

 

[Lauri-CoyoteFrostbite]

Hey MUTNAV

A good question, but its not 46 Mhz
Hydrogen's frequency is 1420.4 (and a lot more numbers trailing off) MHz.
That is derived from the atomic transition of an electron from hydrogen's ground state (1s) that has an energy difference of ~ 6 µeV. The microwave frequency emitted by this transition between the two energy levels is from by the Planck–Einstein's
.
E = hν.

____________________________________________________________________________________

Ahh, Planck's Constant- I have it tatoo'd on my forearm (Not!- tho I should.)

Calculating what 222 Mhz rings is another matter. Anyone one to take the challenge ?

The blue flash seen when a errant copper wire is shorted out is not the same thing as Cherenkov radiation- that is the spectral light given off as a piece of copper volatilize. Cherenkov radiation is the hyper speed 'sonic boom' of radiation particles exceeding light's speed thru air. You do not want to see it like that dramatization -- ever!

The actor who played Louis Slotin would have received over a 100 Sieverts (neutron) dose- (if you look carefully at his blackboard calculations you will see '1000 rads'- he knew he was dead) --- yet those also in the room fared better...
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........... Like in radio, the inverse square law, anyone?

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Lauri

 

[RFI-EMI-GUY]

Hey MUTNAV

A good question, but its not 46 Mhz
Hydrogen's frequency is 1420.4 (and a lot more numbers trailing off) MHz.
That is derived from the atomic transition of an electron from hydrogen's ground state (1s) that has an energy difference of ~ 6 µeV. The microwave frequency emitted by this transition between the two energy levels is from by the Planck–Einstein's
.
E = hν.

____________________________________________________________________________________

Ahh, Planck's Constant- I have it tatoo'd on my forearm (Not!- tho I should.)

Calculating what 222 Mhz rings is another matter. Anyone one to take the challenge ?

The blue flash seen when a errant copper wire is shorted out is not the same thing as Cherenkov radiation- that is the spectral light given off as a piece of copper volatilize. Cherenkov radiation is the hyper speed 'sonic boom' of radiation particles exceeding light's speed thru air. You do not want to see it like that dramatization -- ever!

The actor who played Louis Slotin would have received over a 100 Sieverts (neutron) dose- (if you look carefully at his blackboard calculations you will see '1000 rads'- he knew he was dead) --- yet those also in the room fared better...
.
........... Like in radio, the inverse square law, anyone?

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.
Lauri

I was never clear on how they determined exposure by coins and belt buckles etc. Were there some specific isotopes that could be accurately measured? I wonder what OSHA would have said about that accident. They had no PPE.

Sent from my SM-T350 using Tapatalk

 

[RFI-EMI-GUY]

Hey MUTNAV

A good question, but its not 46 Mhz
Hydrogen's frequency is 1420.4 (and a lot more numbers trailing off) MHz.
That is derived from the atomic transition of an electron from hydrogen's ground state (1s) that has an energy difference of ~ 6 µeV. The microwave frequency emitted by this transition between the two energy levels is from by the Planck–Einstein's
.
E = hν.

____________________________________________________________________________________

Ahh, Planck's Constant- I have it tatoo'd on my forearm (Not!- tho I should.)

Calculating what 222 Mhz rings is another matter. Anyone one to take the challenge ?

The blue flash seen when a errant copper wire is shorted out is not the same thing as Cherenkov radiation- that is the spectral light given off as a piece of copper volatilize. Cherenkov radiation is the hyper speed 'sonic boom' of radiation particles exceeding light's speed thru air. You do not want to see it like that dramatization -- ever!

The actor who played Louis Slotin would have received over a 100 Sieverts (neutron) dose- (if you look carefully at his blackboard calculations you will see '1000 rads'- he knew he was dead) --- yet those also in the room fared better...
.
........... Like in radio, the inverse square law, anyone?

.
.
Lauri

I am guessing the earths magnetic field is what rings with these neutrinos.

Sent from my SM-T350 using Tapatalk

 

[Kfred]

if remember corectly the exposure would be calculated by the distance you are from the source. knowing the level of energy at the source of exposure and calculating the loss of energy as it spreads out will give you exposure levels. i am guessing the metal was removed because it was radiated and had become "hot" and would continue to emit radiation. like most things time and distance are the two most important factors.

 

[Lauri-CoyoteFrostbite]

Years ago when that movie came out I watch'd it for the first time with a bunch of others geeks, and a host of 'normals.'
It was one of those movie nights where someone has a video, pizzas are produced and adult beverages are consumed. What made this all the more interesting was we were watching it up "on the hill"- and everyone knew we were right where this all happen'd.
But not everyone had the technical background to understand what was subtly occurring throughout the movie. So periodically someone would ask

"Why are they doing That !?"

(like the development scenes where the lens is constructed for the plutonium initiator- the explosives and all)

Or-

"Why did they drop all the metallic objects from their pockets ?"
.
Naturally, that scene had to be stopped, and replayed several times.

And that was a good question, too-
Why ?, Because those objects were now all radioactive. By measuring their 'counts,' a more accurate dosage for each individual could be calculated. That neutron bombardment produced a host of radionuclides in everything it irradiated... including the sodium and phosphorus in their bodies, their metallic fillings in the mouths..... Louis Slotin was radiating 15 mRem's when they took him to hospital.... he had a gold crown on a tooth that in the ensuing days burned a hole in his tongue....
What's also remarkable is that the total energy released by that 'experiment' was only about 20 watts, and the reaction went critical for less than a second.

The movie scene was Hollywood. It did occur, but after the war. The need to preform it like that was pure Cowboy, but Slotin was known for his devil-may-care attitude. He had done it some sixty times . Physicists like Fermi had warned against how reckless and dangerous it was, and advised -- "if you are going to do it like that, place safety shims between the sphere halves."


Kind'a on another aside, since I'm all over the place, and now talking plutonium- Plutonium is a marvellous metal-- if marvellous is a good word to describe one of the most poisonous substances on earth. Its metallic sheen changes as it is look'd at. It is radioactive, but only as an alpha emitter- so outside your body- except your eyes, the radiation doesn't penetrate intact skin. Internally its another story.
You *can* actually handle a sphere of it... tho highly doubtful anyone anywhere will ever ever offer the opportunity. But I have seen it up close and personal.

"Like to hold a piece, Lauri ?" I was (not !) seriously asked "It feels really warm from the Alpha radiation even though the metal itself is cold"
I declined - I am not sure what would have followed if I had said

"Why not ?"
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Lauri
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[MUTNAV]

Thanks for the help, I'm really unversed in all of these things, However, I found the reference I was thinking of

regarding the 46 MHZ. Unfortunately it relates to NMR spectroscopy, hydrogen resonance freq
is 42.5775MHZ per volt in a 1 tesla field (per "CRC Handbook of Chemistry and Physics", downloadable online, yeah!!! )... I thought there might be something around 222 MHZ, but it's a no go for a single element. Perhaps an RF spectra would be helpful.

Also, I thought Chernenkov radiation was created when anything going the speed of light was slowed? or did I read to many Star Trek books.

Also, I think the use of shims was ignored in the second demon core incident and a screwdriver was used instead. Wikipedia had an interesting article on the demon core thing. They made it sound like the only person present with any sense was Feynman, who was also the only one there to survive to a ripe old age.
It sounds like you have first hand and up close experience with many really cool science things. I never really had the math background for too much science, I mostly try now just to pay attention to the qualitative aspects.

I'm pleased that you said no to holding the item, maybe it was a sanity check. If you agreed the response easily could have been something along the lines of "You're to careless to be here."

Thanks
Joel

 

[MUTNAV]

My mistake, the wikipedia article lists those present and there lifespans and what they died from.

Thanks again
Joel

 

[Lauri-CoyoteFrostbite]

Hey Mutnav

This is really quite a topic, No ? I had no idea where it would go when I first mention'd it. I appreciate that the moderators have allow'd it this long of a run- tho I hope that everyone will see the science behind the topic and its applications to science minded radio hams.
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I really like your observation:
I'm pleased that you said no to holding the item, maybe it was a sanity check. If you agreed the response easily could have been something along the lines of "You're to careless to be here."
Yes, a security test... Smiles- as if I haven't been thru enuff of those- what a wonderful twist that one would have been.
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Actually, the speed of light is a factor, but the Cherenkov Effect is what occurs when a particle exceeds the speed of light thru a dielectric. Now the physics of why we see it as a blue light I'll leave to inquisitive minds (come'on guys this is the homework assignment )

A high energy Neutrino colliding with an electron can speed it sufficiently to produce the effect. The resultant wave produces the radio signature that this topic unfortunately is drifting away from. There are peaks, like 200-225 Mhz.... did I bring that back on line ?
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Other Loose Ends (?)
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What happen'd the other scientist present when Slotin's test went wrong ? They got sick.. and all probably had their lives shorten'd by the experience. Most them suffer'd life long health issues. I am only vaguely familiar with that aspect of 'the accident,' as it was called.
Remember, that for many years all this was classified.. and RFI-EMI's question about an OSHA over sight ?... at Los Alamos !?
Any OSHA guys would not have gotten beyond the spotlights of the machine gun towers.
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I'll finish off with these neat quotes:
"Neutrinos are everywhere in nature. Every second, tens of billions of them pass through every inch of our bodies without us ever noticing."
and
" Scientists estimate that the explosion of a star inside the Large Magellanic Cloud— released one billion trillion trillion trillion trillion trillion trillion neutrinos by the supernova."
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Kinda' makes you feel insignificant.

Now, how to detect them
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Lauri

 

[prcguy]

Did the original event in the movie clip happen at Los Alamos National Lab? If so I've probably been in the same room. An uncle of mine worked security at the lab around the late 50s through mid 60s and lived most of his adult life in White Rock, NM near the lab and eventually became chief of the NM state police. His wife was a nurse at the lab and I heard she had some plutonium leak stories she would not elaborate on.

Another uncle near Pueblo, CO sold a feller some land around the late 1940s and used to ride horses with him when he vacationed there in between his busy schedule. The fellers name was Oppenheimer and my uncle said he had no clue who he was until he toured Los Alamos Labs much later where he saw a life size picture of Oppenheimer and recognized him.

Years ago when that movie came out I watch'd it for the first time with a bunch of others geeks, and a host of 'normals.'
It was one of those movie nights where someone has a video, pizzas are produced and adult beverages are consumed. What made this all the more interesting was we were watching it up "on the hill"- and everyone knew we were right where this all happen'd.
But not everyone had the technical background to understand what was subtly occurring throughout the movie. So periodically someone would ask

"Why are they doing That !?"

(like the development scenes where the lens is constructed for the plutonium initiator- the explosives and all)

Or-

"Why did they drop all the metallic objects from their pockets ?"
.
Naturally, that scene had to be stopped, and replayed several times.

And that was a good question, too-
Why ?, Because those objects were now all radioactive. By measuring their 'counts,' a more accurate dosage for each individual could be calculated. That neutron bombardment produced a host of radionuclides in everything it irradiated... including the sodium and phosphorus in their bodies, their metallic fillings in the mouths..... Louis Slotin was radiating 15 mRem's when they took him to hospital.... he had a gold crown on a tooth that in the ensuing days burned a hole in his tongue....
What's also remarkable is that the total energy released by that 'experiment' was only about 20 watts, and the reaction went critical for less than a second.

The movie scene was Hollywood. It did occur, but after the war. The need to preform it like that was pure Cowboy, but Slotin was known for his devil-may-care attitude. He had done it some sixty times . Physicists like Fermi had warned against how reckless and dangerous it was, and advised -- "if you are going to do it like that, place safety shims between the sphere halves."


Kind'a on another aside, since I'm all over the place, and now talking plutonium- Plutonium is a marvellous metal-- if marvellous is a good word to describe one of the most poisonous substances on earth. Its metallic sheen changes as it is look'd at. It is radioactive, but only as an alpha emitter- so outside your body- except your eyes, the radiation doesn't penetrate intact skin. Internally its another story.
You *can* actually handle a sphere of it... tho highly doubtful anyone anywhere will ever ever offer the opportunity. But I have seen it up close and personal.

"Like to hold a piece, Lauri ?" I was (not !) seriously asked "It feels really warm from the Alpha radiation even though the metal itself is cold"
I declined - I am not sure what would have followed if I had said

"Why not ?"
.
.
Lauri
.
.
.

 

[RFI-EMI-GUY]

A great cable TV series called "Manhattan" was based on Los Alamos. It was a dramatization because nobody was really keeping records of life on the base.

Sent from my SM-T350 using Tapatalk

 

[Lauri-CoyoteFrostbite]

.
Did the original event in the movie clip happen at Los Alamos National Lab?

Hi PRC

Yes, it did. Here's a photo of it- not very imposing- but none of those 40's era building were built for anything but utility. Its tuck'd away in a side canyon off a lonely mesa, not too far from where I had my facility.
What its used for now ......?

Oppenheimer was quite the enigmatic character- though without him the Manhattan Project might never have been successful. Of course he was well before my time, but when I was at Berkeley I met some old timers who had been in his circle of students. Theoreticians; I could never fit (or want'd to)- into that environment.
In Los Alamos, not far from its famous Lodge, is a statue of him and General Groves- like him or not, for what he did or who he was, he is a celebrated figure at Los Alamos.

And he sure pick'd a beautiful site for the lab.
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Los Alamos today is a quite a mixture of a completely open city to the ultra secure 'Tech Areas." There are only two roads up "the hill"- the first is just a normal highway, but it passes the old security watch towers- preserved as National Historical Sites.
The back road has checkpoints- have your badges ready.


Its not exactly a tourist mecca for the average person, but there is an interesting museum, the Lodge, and places nearby, like my favorite for hiking- Bandelier National Monument .
For those of us that love the feel of a university campus, military base, small modern city- absolutely no crime or unemployment-- its Los Alamos. I am not a booster for the Chamber of commerce, but anyone that wants to take a peek here's a link to begin

Ranger in Your Pocket
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Lauri
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[ladn]

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Okay, so we are on a roll -- here is one of the best simulated movie scenes involving Cherenkov Radiation I can think of. It sends a chill up my spine each time I see it, for the lab building still exists-- and I have stood in there, exactly where Louis Slotin did this experiment real life.
.

Wasn't this called "Tickling the Dragon's Tail"? https://nerdist.com/tickling-the-dragons-tail-the-story-of-the-demon-core/

 

[Lauri-CoyoteFrostbite]

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Hey Ladn
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Yes, that is what it was called, 'tickling the dragon's tail', 'tickling the sleeping dragon'- it went by any number of terms- but all meaning the same thing-- "very Very Stupid !"
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When you come right down to it, what else can be expect'd if you do that criticallity test enuff times? Sooner or later the dragoon is going to wake up, be P*ss'd -- and eat you.
.

Fortunately those sorts of shenanigans are forbidden in any lab today. Even if the core doesn't go critical, everyone in the vicinity is/was explosed to high levels of various radiations.
About the nastiest of the radiation hazards is called neutron activation, which is the ability of neutron radiation to induce radioactivity in substances they encounter--- including body tissues
ie: They will render you radioactive for the rest of your (now shorten'd) life.

I cringe whenever I see any open, unshield'd radiation sources, and tho not required for what I do/have done- I undergo dosimetry tests every blue moon , or so, just for peace of mind.





Lauri




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[RFI-EMI-GUY]

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Hey Ladn
.
Yes, that is what it was called, 'tickling the dragon's tail', 'tickling the sleeping dragon'- it went by any number of terms- but all meaning the same thing-- "very Very Stupid !"
.
When you come right down to it, what else can be expect'd if you do that criticallity test enuff times? Sooner or later the dragoon is going to wake up, be P*ss'd -- and eat you.
.

Fortunately those sorts of shenanigans are forbidden in any lab today. Even if the core doesn't go critical, everyone in the vicinity is/was explosed to high levels of various radiations.
About the nastiest of the radiation hazards is called neutron activation, which is the ability of neutron radiation to induce radioactivity in substances they encounter--- including body tissues
ie: They will render you radioactive for the rest of your (now shorten'd) life.

I cringe whenever I see any open, unshield'd radiation sources, and tho not required for what I do/have done- I undergo dosimetry tests every blue moon , or so, just for peace of mind.





Lauri




.

While it sounds morbid , I wonder if any old gravesites around the lab are HOT?

Sent from my SM-T350 using Tapatalk

 

[ladn]

While it sounds morbid , I wonder if any old gravesites around the lab are HOT?

Sent from my SM-T350 using Tapatalk

I've wondered that as well, but suspect a metal casket (especially if lead lined) combined with deep earth burial in a concrete vault (as is standard in modern cemeteries), would contain the radiation.

 

[Lauri-CoyoteFrostbite]

That's a good question- just how 'hot' were these fellows... especially poor Louis ?


I'm going out on a limb here- I know virtually nothing about nuclear medicine except that I do have my blood drawn looking for the signature traces of radionuclides.... something that would be seen after a neutron exposure (notice I used radio there, still trying to keep this topic centre'd.)

I know that after an immediate exposure to neutrons (and remember that Louis Slotin received a heavy dose of eveything mixed, not just neutrons-- complicating the dose calculation)- after an immediate exposure the radio active (there's "radio" again)- the radioisotope Sodium 24 has a big spike. It has a half life of less than a day, so while Louis was 'hot' immediately afterwards, the counts decreased rapidly thereafter. Phosphorus is in there too, but its half life is like 2 weeks. These are Beta emitters, and I would think any coffin would be a shield, sufficient to see a decay down to safe before they succumb to the ages... but I'm (thankfully) no undertaker. Things like gold dental crowns are another matter.

If you want a grizzly tale, about someone(s) who will be 'hot' for a long long time ... Goggle Eben Byer, Radiothor, and the Radium Girls.

Radium has a really long half life, and Eben was laid to rest in a lead-lined coffin. Radium, btw, is an analogue of Calcium; its like these nightmare irrigation ditches we have in the West- wide, deep, swift flowing ditches often paralell'd by gravel roads-- no banks, no barriers, ---Creepy ! to drive beside-----

"Once In , Never Out"

I never drive anywhere around them- nor would I mess with Radium.


Lauri

____________________________________________________________

oh, there are no graves of any scientists, that I know of, on the 'hill.'

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[RFI-EMI-GUY]

Eben Byer. That is a truly frightening story. Unfortunately we are all being guinea pigs to current pharmaceuticals and supplements.

For an example, I picked this one called PREVAGEN that " contains a substance found in Jellyfish" because it is advertised constantly. Imagine my surprise right now to find the FTC has ruled it a hoax, yet just today I heard the advert again.

Memory pills are a hoax, FTC said in suit against company

Yesterday I read an article about a sculptor who has morbidly poisoned herself over the years creating a masterpiece made of mullosk shells she would saw into tiny pieces creating dust she would inhale in the process. Who would have known that mullosk collect heavy metals in their shells?

You are what you eat.

Sent from my SM-T350 using Tapatalk

 

[Lauri-CoyoteFrostbite]

Oh, I don't know- I run into a lot of people with IQ's of Jelly Fish. Prevegan may be just the thing to boost their intelligence, their memory-

The mullock poisoning is disquieting, however.

I met an engineer years ago that work'd with high power microwaves. He was a Cowboy, much like Louis Slotin. On projects he was quite reckless in exposing himself and other to this non-ionizing radiation.
I fortunately had little contact with him- except once that is most memorable. I and a group of others were down range of a 'blow torch' when one of our guys said

"Do you feel that heat?"

I wasn't being very cerebral at the moment (I should have taken my Prevegan ) - but almost instantly one of our group said

"Sh*T !" .....and push me over to a side ravine-

..........then tore up the hill and had some 'words' with that engineer.

I later heard that fellow had gone practically deaf, most likely to his disregard for stuff like that.


_____________________________________________________

(RFI- love your new Avatar)


Lauri