Cherenkov Effect and Radio

[quad_track]

I was going to post some stupid physics crap, but then I read this: Radium Girls: The Dark Story of America’s Shining Women by Kate Moore. – Glasgow Women's Library

Wow. I had never been exposed to this part of history. Thanks for this.

 

[ladn]

.
...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...
.

From a New Yourker story on "The Demon Core":

...The witnesses to the demonstration were taken to the Los Alamos hospital. Slotin vomited once prior to being examined, and several times more in the next few hours, but stopped by the next morning. His general health seemed acceptable. But his left hand, initially numb and tingling, became increasingly painful. This was the hand that had been closest to the core, and scientists later estimated that it had received more than fifteen thousand rem of low-energy X rays. Slotin’s whole-body dose was around twenty-one hundred rem of neutrons, gamma rays, and X rays. (Five hundred rem is usually fatal for humans.) The hand eventually took on a waxy blue appearance and developed large blisters. Slotin’s physicians kept it packed in ice, to limit the swelling and the pain. His right hand, which had been holding the screwdriver, suffered lesser versions of these symptoms...

...By the seventh day, he was experiencing periods of “mental confusion.” His lips turned blue and he was put in an oxygen tent. Eventually, he sank into a coma. He died nine days after the accident, at the age of thirty-five. The cause was recorded as acute radiation syndrome, also known as radiation sickness. His body was shipped to Winnipeg for burial in a sealed Army casket...

(The Demon Core)

Since television was in its infancy when this event occurred in 1946, it would have been reported via radio and in the print media and probably in film "newsreels". A very inglorious end to a brilliant, though careless physicist.

In the photo below, Slotin, at left, stands with his colleague Herb Lehr beside the first nuclear bomb, here only partially assembled. Photograph courtesy Los Alamos National Laboratory

 

[Hit_Factor]

Cherenkov was a super geek. He predicted the blue glow years before anyone saw it.

I work at a nuclear site. It's mesmerizing to watch the fuel offload.

73, K8HIT
Icom: IC-7300 IC-PW1 ID-5100A ID-51A Plus 2 IC-R30 Hytera PD782G Uniden SDS100 DVMega SDRplay RSPduo

 

[Lauri-CoyoteFrostbite]

I am a fan of Latin American telenovela's- those are Spanish language soap operas (part of my fun of watching Free-to-Air satellites.)

These novelas are different than US soaps- if comparing them to 'soaps' is fair- for they are more like stories- a 'mini series'- with a beginning , and an end. In other words, they don't go on forever.
I hope this topic doesn't turn into a "soap'... so, like a Tele, I think I have explored nuclear physics enuff- and have really nothing further to add....
Oh, except maybe this


Cherenkov radiation is something few will see- hopefully never see under all the many cheerful conditions this topic has discussed.
But here is one source of 'nuclear fire' that I can think of, one that is quite harmless --yet ever so captivating.

My friend, the nuclear physicist, is always coming up with neat things to do with the access she has to her reactors. One of them is her big bag of calcite crystals (calcium carbonate in crystalline form) - that she will put into a beam path of some idling reactor, irradiate it (Not! with neutrons... enuff with those nasty buggers)- changing the calcium's electron valence to a higher, unstable state. When they are removed, they are not radioactive- just radio activated- stable for the moment and just as normal looking as before.

Ahh !... but place them in a small frying pan, put that pan on a hot wood stove, in a tundra-line cabin, dim the lanterns- and they begin to glow with a bright eerie orange light... like live coals from the fire. Pick one up, -- its barely warm.
They will glow for a long time, and of course elicit all sorts of questions about why-- Do I dare get into electro-valence shifts ?.... Naw (smiles) a home work assignment .

Its been fun exploring this stuff with you guys. Perhaps in the ensuing, something else will tickle my scientific (radio centric) interests.

(But please feel free to continue this without me )



Lauri

 

[quad_track]

One of them is her big bag of calcite crystals (calcium carbonate in crystalline form) - that she will put into a beam path of some idling reactor, irradiate it (Not! with neutrons... enuff with those nasty buggers)- changing the calcium's electron valence to a higher, unstable state. When they are removed, they are not radioactive- just radio activated- stable for the moment and just as normal looking as before.

Ahh !... but place them in a small frying pan, put that pan on a hot wood stove, in a tundra-line cabin, dim the lanterns- and they begin to glow with a bright eerie orange light... like live coals from the fire. Pick one up, -- its barely warm.
They will glow for a long time, and of course elicit all sorts of questions about why-- Do I dare get into electro-valence shifts ?....

Interesting. How pure is the substance? Are impurities (natural doping) causing this? Seems like it, and you don't appear to need nuclear radiation, only certain sources of energy tuned to the specific resonating frequencies (aka excitation bands), and room temperature if I read this source correctly: Luminescence, fluorescence and phosphorescence of minerals
It also lists where you can find every colour around the world.
Bet it could also have applications in amateur radio if pushing far enough, although this removes from the equation the wood stove and cabin which are arguably the best part.

 

[N4GIX]

There are many who themselves still believe that Oppenheimer was the "white spawn of Satan" but honestly, someone else would have done the same as he eventually. Where would the world be if -say- the Russians had cracked the secret first? Or anyone else for that matter?

 

[quad_track]

Back to the original topic (amateur radio and Cherenkov effect) since this got terribly sidetracked.
I was mildly annoyed at the "sonic boom" analogy from a practical (amateur radio) point of view, since this analogy seems to treat the neutrinos as particles and the interaction result as waves. I would like to submit that we need to look at this effect both from a particle and a wave point of view.
The particle pov makes us consider the delta mass and the delta velocity of two particles which we can plug into the energy transfer function and derive how much energy we need to use neutrinos as substrate for information transfer.

On the other hand, the particle creates the wave, but the information is still carried by the wave and recovered as another particle's properties on the other end. This concerns the topic of how to recover the information in the optimum way (I could go looking for it on the n-th harmonic but that would not be optimal).
Consider a sine function with origin in 0 and a max amplitude (measuring voltage) of 1. In order to measure the maximum interaction between particles at the time we expect it, we need another sine wave with same polarity and origin and superposition of waves with constructive interference. If we consider a sine wave with reverse polarity but same origin, we get destructive interference and we're into anti-particle territory.
So what function do we need to get minimum interaction _at_the_time_we_expect_it_ but still get "weaker" interaction at some point in time? We need a cosine function (PI/2 delayed) with same polarity but... different origin in time since if we had the same origin in time as our sine wave, we would have a voltage of 1 at the origin and be violating causality. So our "minimum interaction" wave is delayed by PI/2 times frequency and we can measure maximum interaction at 3*PI/4 on the time scale. Now, this time delay translates into phase delay translates into space delta distance so this tells us how to optimally position our antennas in time and thus space if we want to do interferometry.

Now this is a crude simplification into 2D space, but in reality we are dealing with waves in 4D, so we need to consider the amplitude, frequency, polarization and phase delay or time delay of the wave.
I guess what I meant to say is that you can go look for the reverse Cherenkov effect at the origin source, but also, circling back to transmission of information and since quantization effect is a thing, how fast can you quantize the voltage and what is your bit depth resolution? I'd say not enough, from a practical point of view of an amateur radio guy.

 

[RFI-EMI-GUY]

Quad Track; Wow!

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

Stand aside folks, I think the Theoretical Physicist has just entered the room!

This is all above my pay grade!

I am still attempting to visualize the whole particle and wave phenomenon (my brain works better with visualizations) . I picture a wave compression in front of the particle and a wave expansion behind the particle. Does the phase/frequency difference between the forward and following wave fronts work out to this magic 222 MHz in which case we do have a 4D time element because those waves are also somewhat displaced in time. Or am I missing something totally? I have not had my coffee. As far as modulation, maybe the medium can be modulated in physical properties like using a magnetostrictive solution. Then the receiver indeed becomes a problem.

 

[quad_track]

Hang on, I'm no theoretical physicist, I'm a practical guy just like you, and this is just back of the napkin math which amounts to a spherical chicken in the vacuum. If it looks weird, it's just because it's a different mathematical representation aimed specifically at the practical point of the transfer of information. If you want to transfer the information, you can't look at the neutrinos as just particles that you shoot at one end and recover at the other end. You have to look at the wave properties in order to design the most efficient energy converter to overcome the medium discontinuity.
In the end, you're looking at two main questions: how much energy do you need to transfer a specific amount of information, and how do you design the transducer optimally.
Oh, and sorry about the 4D space, I only did that to avoid instantaneous transfer of information, violation of second thermodynamics law and travel in the past. You can mathematically construct M-dimensional spaces to project a wave into a frame of reference, but in the end that amounts to a fancy 3D antenna which can do things like electronic beam steering
If you want to have a laugh about my math, think about the fact that the electromagnetic wave propagates at the speed of light, but by the time the signal reaches your ears, it's at the speed of sound. Real world is not pure math

Reference: xkcd: Models of the Atom

 

[RFI-EMI-GUY]

(snip)
If you want to have a laugh about my math, think about the fact that the electromagnetic wave propagates at the speed of light, but by the time the signal reaches your ears, it's at the speed of sound. Real world is not pure math

Reference: xkcd: Models of the Atom

Well we all know it has to slow down at the receiver or it would knock your headphones right off your noggin!

 

[Lauri-CoyoteFrostbite]

OMG !

(I knew there was a reason to say "Good Night" guys )


.................................. Smiles !

Lauri

 

[quad_track]

Back to calcium carbonate crystals, I think we can use them to do amateur TV at ultraviolet frequencies.
"Hey, I can see you in my crystal ball."

 

[Kfred]

since we have already gone way out in left field . It would be nice if we could build material in a reactor that would work like transistor hole theory. have a depletion area in the material and provide the needed emitter to make it active. Maybe someday learn how to bend an atom and release energy with out destroying it. remember I am an equipment operator ,caterpillar , john deere, etc not a physicist. just random rambling.

 

[BruceMN]

I work in a radiation therapy department as a medical physicist in a hospital where we treat people with cancer using linear accelerators. I have seen Cerenkov light in a water tank irradiated by high energy electrons (6-18 MeV) once. I've only seen it when there is was an extremely high dose rate when the accelerator is being tuned beyond its normal operating limits (when the accelerator is in a failure state while being repaired) and the lights in the treatment room were off. I would imagine it also occurs during normal operation but it is so faint it is not visible. (We have the ability to treat with either high energy x-rays or electrons). I never thought Cerenkov light might produce RF signals in the 220 MHz range. Perhaps this is something I could measure using one of our clinical accelerators.