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Registered Member #1025
Joined: Sun Sept 23 2007, 07:53PM
Location: Czech Rep.
Posts: 566
I have one theoretical question...
Considering that in optically high dense environments can particles travel faster than light and as a consequence Cherenkov radiation is emitted, I’d like to know, how is with salt ions in water.
Water is optically very dense (means high refraction index) and lowest particle energy necessary for Cherenkov radiation emission in water is only around 280KeV. Related to electrons - that’s something most of us can generate by Marx or TC at home.
So my question is: Do you think is it possible to induce Cherenkov radiation in water only by electric current off sufficient voltage (or you still need a particle accelerator)? What if I take water with salt (like NaCl) and use it as a conductor for my 500KV Marx discharge? Can the salt ions exceed the speed of light in the water?
Registered Member #567
Joined: Tue Mar 06 2007, 10:55AM
Location: Singapore
Posts: 147
Well, I cna't be sure, having not much knowledge here- But seeing as you have a marx, water and salt (I hope so anyway!), why not try it out? You might have to limit the current though, or risk blowing the water up. (Instant vaporization of water?)
Registered Member #964
Joined: Wed Aug 22 2007, 12:39AM
Location: Stockton, CA
Posts: 134
EEKER! you know Cherenkov radiation will kill you upon exposure, right? I hope you're going to try this with several feet of lead/concrete between it and any nearby living thing.
It would be interesting to try out.
Wait! metal is like 1000x more optically dense than water. It doesn't make Cherenkov radiation when we put 500kv through it, or the whole subject of EHV would be left alone completely, no TCs shooting 11 foot arcs. I'm thinking no Cherenkov radiation would result if we don;t deep-fry ourselves in radiation every time we turn on our marx/tesla coil
Interesting to try though. I would just be REALLY REALLY careful about the whole thing. :)
Registered Member #567
Joined: Tue Mar 06 2007, 10:55AM
Location: Singapore
Posts: 147
I just did a quick search on Wikipedia and I've found out the answer is no. Quote from wikipedia:
wrote ... ÄŒerenkov radiation results when a charged particle, most commonly an electron, exceeds the speed at which light is propagating in a dielectric (electrically insulating) medium through which it passes.
So it has to be non conductive. So no to salt water.
Registered Member #191
Joined: Fri Feb 17 2006, 02:01AM
Location: Esbjerg Denmark
Posts: 720
Spedy wrote ...
EEKER! you know Cherenkov radiation will kill you upon exposure, right? I hope you're going to try this with several feet of lead/concrete between it and any nearby living thing.
It would be interesting to try out.
Wait! metal is like 1000x more optically dense than water. It doesn't make Cherenkov radiation when we put 500kv through it, or the whole subject of EHV would be left alone completely, no TCs shooting 11 foot arcs. I'm thinking no Cherenkov radiation would result if we don;t deep-fry ourselves in radiation every time we turn on our marx/tesla coil
Interesting to try though. I would just be REALLY REALLY careful about the whole thing. :)
eh? who told you that? It's "just" light, well not all visible but still just light. BUT, if you are looking at a pool of water emmitting blue light(think movie K19), you are pretty much done for.
Registered Member #1025
Joined: Sun Sept 23 2007, 07:53PM
Location: Czech Rep.
Posts: 566
Firnagzen wrote ...
I just did a quick search on Wikipedia and I've found out the answer is no. Quote from wikipedia:
wrote ... ÄŒerenkov radiation results when a charged particle, most commonly an electron, exceeds the speed at which light is propagating in a dielectric (electrically insulating) medium through which it passes.
So it has to be non conductive. So no to salt water.
Actually I red that too, but I do not understand why only dielectrics should emit Cerenkov light. First of all the term dielectric is very relative (all materials are conductors – it is just a question of voltage). I think that for detectors of Cerenkov radiation where the deionised water is used it has something to do with the measuring procedure and not that the deionised water is bad electric conductor.
I have one litle bit indirect proof that Cerenkov radiation can be produced also in electrically conductive enviroments. It is the flashes of light the astronauts see during the stay on the orbit. It was shown that those are Cerenkov light emissions caused by an interaction of high energy particles with the vitreous humour - which as I suppose is full of salt ions...
Firnagzen wrote ...
Well, I can't be sure, having not much knowledge here- But seeing as you have a marx, water and salt (I hope so anyway!), why not try it out? You might have to limit the current though, or risk blowing the water up. (Instant vaporization of water?)
Of course I tried it – here are the pictures – but honestly the light emitted from the water seems to be too strong to call it cerenkov radiation so easily (but on the other hand the energy of the dischgarge is almost 100J).
But supportive arguments for this theory are: I've never seen the emission of light when my marx was 200KV only. I also miss the yellow glow of natrium which should be visible in case plasma was generated…
I plan to make a better setting of the experiment and get better camera soon. I'd like to hear more of your opiniens and hints...
Thanks
here is my old 500KV 100J setting (there is a salt water in the plastic tube and two electrodes from the top and bottom are dipped inside)
And here is my new marx (still in progress) where every stage has 65KV - it means over 300KV sparks at the moment. In this case the discharge is visible on both pictures which sometimes happens (it looks that the CCD chip has a problem to recover from the amount of light which stays burned into the chip for some time)
BTW: ear-plugs are absolutelly neccessary for these experiments
It would be also great if somebody of you owning a TC which can make sparks over 1m (unfortunately it is not my case) could perform similar experiment
Registered Member #96
Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4061
Electroholic wrote ...
Spedy wrote ...
EEKER! you know Cherenkov radiation will kill you upon exposure, right? I hope you're going to try this with several feet of lead/concrete between it and any nearby living thing.
It would be interesting to try out.
Wait! metal is like 1000x more optically dense than water. It doesn't make Cherenkov radiation when we put 500kv through it, or the whole subject of EHV would be left alone completely, no TCs shooting 11 foot arcs. I'm thinking no Cherenkov radiation would result if we don;t deep-fry ourselves in radiation every time we turn on our marx/tesla coil
Interesting to try though. I would just be REALLY REALLY careful about the whole thing. :)
eh? who told you that? It's "just" light, well not all visible but still just light. BUT, if you are looking at a pool of water emmitting blue light(think movie K19), you are pretty much done for.
Depends on dosage. IIRC a second or two of exposure may cause damage but its dosage over time that kills.
In any case K-19 wasn't accurate at all, the worst effects are too gruesome for film, including:- Massive oedema (swelling), blood vessels erupt all over the body, basically what you have is third degree burns. Oh, and the damage extends through the muscles so you end up practically immobile after more than an hour or so.
I did recall reading somewhere that most of the short term effects of radiation can be reduced by infusion of electrolytes, as well as some new peptides (something to do with inhibiting apoptosis IIRC) but that would be a stopgap measure at best.
Registered Member #1025
Joined: Sun Sept 23 2007, 07:53PM
Location: Czech Rep.
Posts: 566
Conundrum wrote ...
Depends on dosage. IIRC a second or two of exposure may cause damage but its dosage over time that kills.
In any case K-19 wasn't accurate at all, the worst effects are too gruesome for film, including:- Massive oedema (swelling), blood vessels erupt all over the body, basically what you have is third degree burns. Oh, and the damage extends through the muscles so you end up practically immobile after more than an hour or so.
I did recall reading somewhere that most of the short term effects of radiation can be reduced by infusion of electrolytes, as well as some new peptides (something to do with inhibiting apoptosis IIRC) but that would be a stopgap measure at best.
-A
"Bother" said Pooh, as he hit the SCRAM button...
Cerenkov radiation by itself is more or less harmless because it is just low energy photons (It has peak emmission in UV spectrum but that's all the danger) . What is usually not harmless is what causing this radiation - means high energetic particles. But even here the real danger is a qustion of dose and energy of the particles.
Registered Member #964
Joined: Wed Aug 22 2007, 12:39AM
Location: Stockton, CA
Posts: 134
Oh I get it now. lol, I got confused there. thanks for clearing it up. Well, since the Na and Cl ions arn't exactly going to be shooting at you at full speed, I don't really see any danger. I was going to tell everyone how you deep-fried yourself w/ a marx and a glass of salt water. :P
Anyway, still interesting. For the thing w/ the marx being too bright, I think some kind of cover, or move it off-frame (you prob thought of this already though), and for the water's flash, I have no idea how to help that that won't block the blue glow aswell.
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Cherenkov radiation, HV and home experiments
