Score
Title
98
AskScience Panel of Scientists XVIII
550
AskScience AMA Series: I am Melinda Krahenbuhl and I am the director of the Reed Research Reactor, the only nuclear reactor operated primarily by undergraduate students. AMA!
8468
What elements are at genuine risk of running out and what are the implications of them running out?
269
Can you break sound barrier under water or any other material?
4021
What’s the largest star system in number of planets?
19
Why does plastic turn white at the creases when folded/bent?
3
How does thermal imaging work?
21
Do microwaves leave residual changes to molecules after heating?
4
Can a setup of hall engines provide enough thrust to keep a satellite stationary above earth?
2
Does the temperature have any (noticable) effect on air resistance?
6
How does a memristor work?
1
How does radiation poisoning work?
1
How is the height of the mountain measured?
3827
What is the effect, positive or negative, of receiving multiple immunizations at the same time; such as when the military goes through "shot lines" to receive all deployment related vaccines?
4
If a planet had a radius that was equal to the altitude of Earth’s geosynchronous orbit, but had the same mass and rotational period as the Earth now, would there be reduced or zero gravity on the surface?
1
What is lost and what is preserved in a particle collider?
8
Why does snow melt in the sunlight, even when the temperature outside is below freezing?
11
Mar's summer temperature can be 20 celsius. Could a human survive with just an oxygen mask?
2
Is there an altitude at which there is no longer a speed of sound?
0
How would a moving target affect the rate of nuclear fission vs a stationary target?
14
What would a spaceship moving at 0.9c firing lasers both in front of it and behind it look like to an external reference frame?
6
Does adiabatic warming occur when air descends in the Earth's polar cells?
24
How does the cosmic microwave background persist? Why hasn't it been distorted and destroyed by new sources of energy pumping into space?
6
How does cancer metastasis work?
7
Can a comet maintain an atmosphere?
1
How does RFID blocking material work?
0
Does the Meissner effect relate to Lenzs law?
9
Why hasn't The Asteroid Belt formed a planet?
10
Can you use a normal (CMOS) camera for detecting scintillation?
3
How do people know that the Island of Stability exists? And could there possibly be another "island" after it?
59
How can brain cells cause tumours even though they can not multiply?
7
How far back can you go before carbon dating becomes unreliable?
2
How does a computer process “simple” events?
1578
Ask Anything Wednesday - Biology, Chemistry, Neuroscience, Medicine, Psychology
3
What is the nonrenewable fuel cost to produce x quantity of electricity?
1132
What triggers beta particles to form, and for what reason can they not penetrate substantially thick aluminium?
0
What is the strongest a magnet could be?
1242
If capacitance increases as distance between plates decreases, why aren't there very small 1F capacitors?
0
What makes astronomers think life in general isn't possible on gas giants?
1
How applicable are Newtonian Physics in real life? Is it completely false or are there some concepts which can be used to accurately predict real-life situations?
1050
is it possible to move an object in circular motion using magnets?
4
What would hydrogen in metal form look like?
1162 cantgetno197 The wavelength of light that comes out of an X-ray laser is in the tens of nanometers, versus in the hundreds of nanometers that comes out of a "regular" (i.e. visible wavelength) laser and versus the hundreds of millions of nanometers that came out of their fore bearer the maser (Microwave-aser). But, at the end of the day, it's all light and all the same basic mechanism.
90 antimony121 To perhaps add a few more details to the main difference mentioned already (energy of the light being produced) *and explain differences in the process of creating x-ray beams: It might first be useful to point out that laser light, unlike that from a light bulb, is coherent, so all the light waves are in phase with one another which is a direct result of how the energy is produced. In standard lasers, this energy is coming from the relaxation of excited electrons (excited by some mechanism, pretty much always deliberate to ensure the highest probability for the relaxation of the energy you're wanting, using something like a flash lamp, electric current, or even another laser, depending on the specific type of laser). The relaxation gives off the light you're looking for. Once this happens in one electron, that light prompts a neighboring, similarly excited electron to do the same with the nice bonus of doing so perfectly in phase with the original stimulating light/photon (this is the "stimulation" and "amplification," since you're getting two for the price of one, in the acronym that makes the word laser -- Light Amplification by the Stimulated Emission of Radiation). Since this means you need to have the electrons excited to an energy at least as high as the energy you want to get out of the laser, and for a relatively long amount of time as far as atomic/molecular excitations are concerned, the higher the lasing energy, the harder the process is to control and produce. When you reach the energy of x-rays, this is so much that it will usually just ionize whatever is being excited, stripping off the electron completely, which kills your shot at the whole coherent light production process. The first x-ray lasers got around this by using just the high energy electrons themselves, produced in [linear accelerators](https://portal.slac.stanford.edu/sites/lcls_public/aboutlcls/Pages/About-LCLS.aspx), using magnetic field to giggle them back an forth fast enough to give of coherent x-rays. More recently (and using technology I'm still trying to get my head around fully that totally blows my mind), [table-top x-ray](https://jila.colorado.edu/kmlabs/research/articles/attosecond-nonlinear-optics) lasers are coming out that are made by -- in the absolute simplest of analogies that doesn't completely capture the process -- almost but not quite ionizing atoms by kind of slingshotting electrons around their nuclei in such a way that the angular acceleration it gains has the x-ray energy you want, which it then gives off as it relaxed back to its regular orbit around the nucleus. Again, the details of this one I'm still catching up on so I hopefully I'm not too off on these points and it still makes some kind of sense. Not sure how much you already knew about laser physics, so sorry if this is overly in-depth and telling you stuff you already knew. I didn't mention some of the other aspects that will affect the type of light you get out (such as pulsed lasers vs. CW that are a single wavelength emitted constantly), but I'd be happy to further elaborate if you're interested.
9 LeWorgen The frequency is higher i.e. the energy in an X-ray laser is higher (E=hv, where E is the energy of the photon, h is the plank constant and v is the frequency), therefore more dangerous than a regular (visible-light) laser.
9 BeardySam Lots of good answers here so I'm just throwing in a fact not a lot of people know: the US 'Star Wars' program under Reagan was a space-bourne x-ray laser, using a nuclear bomb to pump the states of the lasing medium.
3 XJindosh Awesome, thanks! Is the difference down to the geometry of the magnets? Or is there other differences between the two? (I.e. input beam properties) I'd imagine for the broadband source you'd need an electron pulse with a larger range of kinetic energies, whilst the converse would be true for the narrow band output? Which leads me to think it's more than the geometry of the magnets....
1162 0 cantgetno197 The wavelength of light that comes out of an X-ray laser is in the tens of nanometers, versus in the hundreds of nanometers that comes out of a "regular" (i.e. visible wavelength) laser and versus the hundreds of millions of nanometers that came out of their fore bearer the maser (Microwave-aser). But, at the end of the day, it's all light and all the same basic mechanism.
90 0 antimony121 To perhaps add a few more details to the main difference mentioned already (energy of the light being produced) *and explain differences in the process of creating x-ray beams: It might first be useful to point out that laser light, unlike that from a light bulb, is coherent, so all the light waves are in phase with one another which is a direct result of how the energy is produced. In standard lasers, this energy is coming from the relaxation of excited electrons (excited by some mechanism, pretty much always deliberate to ensure the highest probability for the relaxation of the energy you're wanting, using something like a flash lamp, electric current, or even another laser, depending on the specific type of laser). The relaxation gives off the light you're looking for. Once this happens in one electron, that light prompts a neighboring, similarly excited electron to do the same with the nice bonus of doing so perfectly in phase with the original stimulating light/photon (this is the "stimulation" and "amplification," since you're getting two for the price of one, in the acronym that makes the word laser -- Light Amplification by the Stimulated Emission of Radiation). Since this means you need to have the electrons excited to an energy at least as high as the energy you want to get out of the laser, and for a relatively long amount of time as far as atomic/molecular excitations are concerned, the higher the lasing energy, the harder the process is to control and produce. When you reach the energy of x-rays, this is so much that it will usually just ionize whatever is being excited, stripping off the electron completely, which kills your shot at the whole coherent light production process. The first x-ray lasers got around this by using just the high energy electrons themselves, produced in [linear accelerators](https://portal.slac.stanford.edu/sites/lcls_public/aboutlcls/Pages/About-LCLS.aspx), using magnetic field to giggle them back an forth fast enough to give of coherent x-rays. More recently (and using technology I'm still trying to get my head around fully that totally blows my mind), [table-top x-ray](https://jila.colorado.edu/kmlabs/research/articles/attosecond-nonlinear-optics) lasers are coming out that are made by -- in the absolute simplest of analogies that doesn't completely capture the process -- almost but not quite ionizing atoms by kind of slingshotting electrons around their nuclei in such a way that the angular acceleration it gains has the x-ray energy you want, which it then gives off as it relaxed back to its regular orbit around the nucleus. Again, the details of this one I'm still catching up on so I hopefully I'm not too off on these points and it still makes some kind of sense. Not sure how much you already knew about laser physics, so sorry if this is overly in-depth and telling you stuff you already knew. I didn't mention some of the other aspects that will affect the type of light you get out (such as pulsed lasers vs. CW that are a single wavelength emitted constantly), but I'd be happy to further elaborate if you're interested.
11 0 LeWorgen The frequency is higher i.e. the energy in an X-ray laser is higher (E=hv, where E is the energy of the photon, h is the plank constant and v is the frequency), therefore more dangerous than a regular (visible-light) laser.
8 0 BeardySam Lots of good answers here so I'm just throwing in a fact not a lot of people know: the US 'Star Wars' program under Reagan was a space-bourne x-ray laser, using a nuclear bomb to pump the states of the lasing medium.
3 0 XJindosh Awesome, thanks! Is the difference down to the geometry of the magnets? Or is there other differences between the two? (I.e. input beam properties) I'd imagine for the broadband source you'd need an electron pulse with a larger range of kinetic energies, whilst the converse would be true for the narrow band output? Which leads me to think it's more than the geometry of the magnets....