Tiny X-rays of Tiny Animals 30
Johnny Vector writes: "Scientists at Cornell have taken X-rays of fruit flies, with enough detail to see the hairs on their wings. The AIP has more photos. They did it with an "X-Pinch" machine: vaporize a wire, the resulting plasma implodes, producing a tiny (1/1000 inch), fast (nanosecond) pulse of X-rays. I want one of those machines."
Stop it! You're hurting them! (Score:1, Funny)
I'm starting an organization to protest and combat these evil scientists! Please join the Brothers United for the General Rights Of Fruit Flies today!
Or write for more information at:
Information
c/o BUGROFF
10101 Dolth Ave. N
Ani, MA 11111
Re:Stop it! You're hurting them! (Score:1)
Just yesterday I noticed a fruit-fly swimming around in my girlfrinds cup of cold coffee. We have a little compost bin in the kitchen that we don't empty often enough. It (the fly) was swimming around and around, occasionally bumping into a drowned friend.
For some reason, I fished it out and put it on the saucer. I walked around, still submerged in milky coffee, suface tension sticking it to the surface of the saucer, leaving a trail of coffee as it walked and still on its way to drowning.
I put some water in the palm of my hand and gingerly picked up the fly on the tip of my finger and dunked in in. Once in the water it suddenly started walking around much faster, totally under water, free of the oils from the milk. Still drowning, though.
I drained from my palm. It was left again stuck within the confines of the liquid stuck to its body. I touched it with a tissue and the water wicked away. It began walking around like a normal fly, only its wings now stuck down.
For the next few minutes I watched it crawl around the hairs on my wrist, pausing every now and again to clean its head, legs and wings in that very-fly-like way.
Then, zip, it took off again.
A few moments later, my girlfriend return and sat beside me with a book. The fly did a couple of low passes over the pages and was promptly swatted.
And so it goes.
Fascinating (Score:2)
Doctor "Yes, I'm sorry, but you seem to have broken several cilia on your last divide."
Actually wonder if they can use this for etching micro machines
X-rays from ordinary electrical fuses (Score:3, Interesting)
Any electrical spark of sufficient energy density can generate X-rays as well as emissions in other regions of the EM spectrum, especially visible and UV light. For example, you can also get emissions of X-rays from many types of electrical safety fuses when a massive excess of electrical current causes them to blow.
The X-ray emissions from a fuse are detectable with the help of a well-equipped physics lab. However, the emissions you get are not very useful, being neither of short duration nor a single point source emission. By contrast the researchers at Cornell are using carefully constructed crossed wires which produce extremely short picosecond point-source pulses of X-rays.
Re: Did you just guess that that would happen? (Score:2, Informative)
Yes you get RF emission and visible light and even a substantial amount of UV. But if you knew anything about the EM spectrum that you mentioned in your post, you would know that x-ray photons are a thousand times more energetic than UV photons and the puny spark in a blown fuse at household current could not possibly create x-rays.
The Z-machine [sandia.gov] at Sandia National Labs uses up to 20 Million amperes!! to pinch its plasma fusion experiments. In order to create x-rays from a pinch you need to heat the plasma in the pinch to millions of degrees celsius; the x-rays are produced by hot plasma radiating its energy through bremsstrahlung emission and the nuclei-electron recombination time during plasma cooling.
Re: X-rays from ordinary electrical fuses (Score:4, Informative)
What the previous poster says is completely wrong. You always get X-rays even from ordinary electrical sparks such as from fuses blowing. The ideas explaining this fact have been known since the theories of quantum mechanics were developed in the 20th century.
Planck's Law [egglescliffe.org.uk] states there are emissions of electromagnetic radiation at all wavelengths from zero to infinity, i.e. including visible light, infrared, ultraviolet, x-ray, gamma ray, etc.
Planck's Law of Energy Distribution:
L is the wavelength of emitted radiation [metres],
T is the temperature of the black-body emitter [Kelvin],
c is the speed of light (3x10^8 metres/second),
k is Boltzmann's constant (1.38x10E-23 Joules/Kelvin),
h is Planck's constant (6.62606891 x 10E-34 Joule seconds), and
PI is the mathematical constant (3.14159...)
The electromagnetic emissions are strongest at one wavelength given by
Wien's Law [egglescliffe.org.uk]
There is a simple experiment to give a visible indication that a wide range of wavelengths is emitted by electrical sparks. Wearing gloves and safety eye glasses, connect a short 2cm length of 1Amp fuse wire across the two terminals of a low voltage supply like a 12Volt car battery. The fuse wire will blow. Notice the color of the centre of the spark is roughly white. This is because the temperature of the vaporised metal from the fuse wire, created when the fuse blows, momentarily exceeds 5000K, giving a wavelength of peak emission by Wien's Law of 580nm (green light).
If you want to understand more about the electromagnetic spectrum, there is a great summary of the quantum mechanics of black body radiation here [egglescliffe.org.uk]
Re: X-rays from ordinary electrical fuses (Score:2)
It dosen't matter how many equations you fill your post with, you are still violating thermo. law with the assumption that blackbodies emit at ALL wavelenghts. This is due to the fact that as you stated, EM emission is quantized!!
Let's take the example you gave for an emitter at 5000 Kelvins. You were right(close) that it will peak at an emission of 578 nanometers, giving white light; fine. Now apply the value of 5000K to the plank energy distribution formula to derive the power emitted at....oh lets say 10^20 Hz (gamma rays), (this corresponds to a wavelength of ~1 picometer in the gamma ray range and, according to you, this must be emitted by the spark); you get: Power=[2*3.14159265 st*speed of light^2]/[10^-12 meters^5*(e^(6.626 x 10^-34*c/10^-12 meters*boltzmann const of 1.38 x 10^-23*5000K))]=3.7469e-16/1*10^60(2.7182818^8642
Re:X-rays from ordinary electrical fuses (Score:1)
The X-ray emissions from a fuse are detectable with the help of a well-equipped physics lab.
A well-equipped physics lab will also let you construct Battlecruisers, but I don't see any slashdot stories about it...
double exposure (Score:1)
What about when they get two point sources? Is the resulting image totally blurred/mucked up?
Doesn't that make a double exposure on the x-ray film? Would not the two illuminating point sources make a stereo image? Then you would be talking about a very tiny and detailed three dimensional x-ray images of flies. I assume they would need to develop a digital filter that could amplify the stereo separation of the image, as the two point sources of x-rays are quite close to each other...
Re:double exposure (Score:2)
You only get a stereoscopic image if you store each (single-source) image on a different piece of film. Two light sources for the same piece of film just gives you a double exposure. The next time you're walking in the evening, stand between two street lights and look at your shadow for an example of this; you're not going to get a 3D picture of yourself from those shadows very easily.
Practical Uses - Chip Etching? (Score:2)
Re:Practical Uses - Chip Etching? (Score:1)
I hope they don't ignite the atmosphere... (Score:1)
Re:I hope they don't ignite the atmosphere... (Score:3, Informative)
See, for example, this Scientific American article [sciam.com] about "Z-pinch fusion".
Re:I hope they don't ignite the atmosphere... (Score:1)
That would certainly generate x-rays!
"Pinches" (Score:1)
Does anyone know how these "pinches" work, or have a link to a good site or paper that explains what they are?
Re:"Pinches" (Score:3, Informative)
The pinch effect is created by the strong axial magnetic field created by the current flowing through the material in question. See here [electronicstheory.com] for illustrations of magnetic fields. In the case of the article they used two crossed wires which were vaporized to a plasma(therefore still conducting like a wire) by high current. You can picture the strong magnetic field wraping cylindrically around (and squeezing inward with increasing current) the vaporized wire/plasma's axis. At the intersection of the two wires there would then be a small bubble of highly compressed plasma which is heated to extremely high temperatures, as the plasma cools there is a fast plasma "recombination" where the electrons rejoin their nuclei and emit a fast burst of x-rays.
(IANAP so if someone here is, and there is a mistake anywhere feel free to correct me)
If you instead picture an annular array of wires(eg. 10-20 wires) rather than two crossed wires than you can see that the individual magnetic fields of the wires combine into one huge axial field. This is the so called Z-pinch (because the magnetic field is in the "z" axis). These are the pinches used to initiate thermonuclear fusion in machines like this [sandia.gov].
As an aside: Sandia used to use an X-Pinch to "backlight" implosion experiments on the Z-Machine with x-rays so that they may be imaged. Recently they upgraded this setup with a more reliable method of x-ray backlighting using ultrahigh power laser pulses to heat a metal foil target that then creates x-rays. The place where I work supplied the laser parts.
?animal research? (Score:1)
Fruit flies aren't animals. They're insects....
Re:?animal research? (Score:1)
...As opposed to minerals or vegetables? Of course they're animals!
Re:?animal research? (Score:1)