blue glow?

[Johnny5]

hold your horses

you did it right the first time

the angle was 30 degrees

 

the speed of the electrons is not supposed to come out bigger than c

 

it is supposed to come out bigger than the speed of light in the medium

which in this case is the speed of light in water which is 0.75c

 

Yes, I realized that as soon as I went away.

 

But I am right about the angle. That has to be measured by some experiment.

[swansont]

Yes' date=' I realized that as soon as I went away.

 

But I am right about the angle. That has to be measured by some experiment.[/quote']

 

And it has been. The equation fits the data. You can plug in your own numbers and get the expected results for other conditions.

[Johnny5]

And it has been. The equation fits the data. You can plug in your own numbers and get the expected results for other conditions.

 

And thank you too swansont for everything. You may not realize how much of a help you have been, but you have. Your posts are some of the ones I read closely.

 

Just wanted to say thanks

[Guest tinman]

EwWwWwWw )

 

cool stuff! Thanx man' date=' you`re a star

 

I`m glad it added the part about the Vacuum though, I don`t want to start another FTL frenzy again

it`s a beautifull blue color though, I`de love to see it 1`st hand with my own eyes.[/quote']

I was one of first to fuel reactors and was in pool to do it at that time only wet suite. There was some black stuff in reaction area. They said it was bacteria that lives in the reaction zone. This was just Commercial Diving job nothing special. The reaction destroys the welds on the fuel rod containers by bombarding them. The rods are about 1400 degrees when the go to storage yard to cool off. Its not dangerous as water is sheld I was told but first time to do it was very strange.

Jim

[Johnny5]

I was one of first to fuel reactors and was in pool to do it at that time only wet suite. There was some black stuff in reaction area. They said it was bacteria that lives in the reaction zone. This was just Commercial Diving job nothing special. The reaction destroys the welds on the fuel rod containers by bombarding them. The rods are about 1400 degrees when the go to storage yard to cool off. Its not dangerous as water is sheld I was told but first time to do it was very strange.

Jim

 

Don't do it twice.

[mmalluck]

okay, now I have a question for you, it probably trivial, but it's been years since I've been in a physics class.

 

What would the energy of said electron be in eV as it speeds through the water at .866c?

 

Just wondering if I could crank out my high voltage stuff and make my own Cherenkov effect.

[Johnny5]

okay' date=' now I have a question for you, it probably trivial, but it's been years since I've been in a physics class.

 

What would the energy of said electron be in eV as it speeds through the water at .866c?

 

Just wondering if I could crank out my high voltage stuff and make my own Cherenkov effect. [/quote']

 

mass of electron = 9.10953 x 10^-31 kilograms

 

c=2997924358 meters/second

 

[math] .866c = (.866)(299792458) = 259620268 meters/second[/math]

 

Using classical kinetic energy formula

 

[math] T = \frac{mv^2}{2} [/math]

 

So for v = 259620268 meters/second you have:

 

[math] T = \frac{mv^2}{2} = \frac{(9.10953 \times 10^{-31})(259620268 )^2}{2} = 3.1 \times 10^{-14} \text{Joules} [/math]

 

Now, just convert from Joules to electron volts.

 

[math]1 = 1.60219 \times 10^{-19} \frac{\text{Joules}}{eV} [/math]

 

[math] \frac{3.1 \times 10^{-14}}{1.6 \times 10^{-19}} = 191887 eV[/math]

 

Regards

[swansont]

Using classical kinetic energy formula

 

 

 

A Classical formula for a relativistic effect? And such egregious use of significant digits, too.

 

 

 

For v=.866c, gamma is 2. So the kinetic energy is equal to the rest energy, or 0.51 MeV

[YT2095]

Hmmm... just an idea, if Mmalluck used his HT electrical output to trigger an X-Ray tube that was underwater, would there be any effect at all in the visual range?

[mmalluck]

Yeah, .51 MeV is alittle out of the range of most people's high voltage equipment, but x-rays can be made with voltages as low as 30kv or so.

 

I know they make quartz glass glow green, I don't know about water.

 

Edit: But isn't an X-ray just a energetic photon? In that case, it's stuck going at .75c just like a light photon, thus no pretty blue glow.

[soulestada]

If radioactive material emits a blue glow under certain conditions, then what is this green glow that has always been associated with radioactivity?

[swansont]

If radioactive material emits a blue glow under certain conditions, then what is this green glow that has always been associated with radioactivity?

 

Mostly Hollywood, I would guess. Also possibly the green phosphor used to detect charged radiation.

[YT2095]

a few Plutonium compounds such as PuCl3 and PuO2 are green or yellow-green also.

[jdurg]

A good deal of the early zinc-sulfide based paints, used in conjunction with radioactive salts, were of a green color and gave off a green glow when exposed to the radiation. Also, uranyl acetate has been used for a while and is a nice bright green color.

 

One other neat thing is that you don't need to have a radioactive source under water for it to display the Cerenkov radiation. Pure actinium metal is so intensely radioactive that it emits a blue 'Cerenkov Glow' in plain atmospheric air. Many of the high level radioactive metals display this glow, though photographs of it are fairly rare since nobody really has a need, or a want, for pure radioactive metals. (I should know because I've spent quite a long time trying to get a good picture of pure protactinium, actinium, etc. etc. They have been made in large quantities of the pure metal numerous times in the past, but photographs which were supposedly taken are nowhere to be found).

[YT2095]

off topic I know, but would the use special film/camera or sheild be needed to take the pics?

 

I only ask this because to create such a "Glow" reaction in free air, surely it would expose the film long before you got close enough.

 

also in use as a compound in scintilation counters is Sodium Iodide (a nice bright yellow color).

[mmalluck]

Lets not forget all the radium clock dials made during the 40's and 50's that glowed with a nice green color. That's probably where hollywood gets it from.

[swansont]

Lets not forget all the radium clock dials made during the 40's and 50's that glowed with a nice green color. That's probably where hollywood gets it from.

 

Again, though, that's the phosphor you are seeing.