Nuclear reactor there is radiation called like sarencobe radiation

[cragar]

My physics teacher today said in a nuclear reactor there is radiation called like sarencobe
radiation I didn't hear him very well so I don’t know how to spell it ,
he said it is this erie glow in the water when the neutrons out run the light
in the water , can anyone tell me how to spell it or what it is I searched the internet for it but could not find anything.

 

[Pengwuino]

http://en.wikipedia.org/wiki/Cherenkov_radiation

 

[cragar]

wow i really misspelled what i thought he said thanks .

 

[cragar]

so what causes the light to be emitted in cherenkov radiation the electrons
move through the water faster then light but how is the light emitted.

 

[turin]

It is sort of like the EM equivalent of a sonic boom. The field builds up and produces a broad spectrum conical front.

 

[cragar]

ok so what elements are making up that light.

 

[Danger]

It's not a matter of what elements are involved. Photons always travel at c; it's the interaction with atoms that determines the propagation speed of the light signal. In some cases, such as uranium storage pools, sub-atomic particles can travel with less interference from atoms. That occasionally allows them to get to the finish line ahead of the photons.

 

[cragar]

I guess what I am asking is like when a neon lamp makes light you get this orange glow and you can tell that neon atoms made up that light .
so do the electrons coming out of the reactor into the water and interfering with the water molecules cause the light to be emitted .

 

[Danger]

In a storage pool, the usual culprit is a fast neutron. Electrons don't really contribute.
The spectra of various elements are not connected to this phenomenon.

 

[cragar]

ok i see thanks for answering

 

[Danger]

You're more than welcome. I can't help thinking, though, that this might get better responses if it were moved to the 'Atomic, Solid State and Comp. Physics' sub-forum. That seems more in line with what you're investigating.

 

[Bob S]

Cerenkov radiation (sometimes spelled Cherenkov) is produced by beta-decay electrons traveling faster than light (photons) in water. The speed of light in vacuum is about 3 x 10^8 meters per sec, but only about 2.25 x 10^8 meters per sec in water (index of refraction n=1.33 in water). The beta decay electrons travel faster than 2.25 x 10^8 meters per sec (hence faster than photons in water), but slower than 3 x 10^8 meters per sec in water, so they radiate visible blue light. This glow continues as long as the fuel rods in reactors are radioactive, and has no direct connection to neutrons.

 

[Danger]

I stand corrected. Thanks, Bob. I was relying on something that I half-remembered from my visit to the Douglas Point reactor back in the late 60's; I haven't really paid much attention since then.

 

[cragar]

so it has nothing to do with nuetrons , my physics professor said it was because the nuetron's were out running the photons.

 

[Bob S]

so it has nothing to do with nuetrons , my physics professor said it was because the nuetron's were out running the photons.

Only charged particles produce Cerenkov radiation. I recall looking down into a (water) pool-type reactor while it was running, and seeing the eery blue glow. I have also seen it when a charged particle beam was going through glass.

 

[QuantumPion]

I think the term "erie" is a good way to describe Cerenkov light, especially if you have seen spent fuel rods or pool-type reactors in person. It is erie, because you can't really tell what the source of the light is, it almost appears as if it is glowing through the opaque metal rods although it is actually coming from the water itself. But the light also shrouds the fuel in a sort of fog, making it appear ghostly.