# Tag Info

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The X-rays come from hot gas orbiting around the black hole in an accretion disk. As the gas orbits, magnetic stresses cause it to lose energy and angular momentum, thus spiralling slowly in towards the black hole. The orbital energy is transformed into thermal energy, heating up the gas to millions of degrees, so it then emits blackbody radiation in the ...

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My understanding is that any radiation emitted "from a black hole" is actually originating from or just outside the event horizon of the black hole. This is the region beyond which the escape velocity is at or above the speed of light (electromagnetic radiation). Outside the event horizon, escape is still possible. There is another kind of radiation, ...

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X-rays are electromagnetic waves, just as light rays are. The difference is in the wavelength (thus frequency and Energy ). So your question has the same answer as "What happens if you shine light on light" or "What happens if you point a light ray at a light ray". Classically, you will see the same effects you see with usual light rays, interference, ...

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The goal of such a treatment is to induce damages in the cells of the tumor by mean of ionizing radiation. These radiations can be X-rays (photons), electron, proton or things like carbon ions. The problem is: if you try to irradiate a tumor, you first have to go through normal tissues and the risk is to damage them also. Photons will transfer energy ...

4

Roughly yes. Radiation is broadly divided into two from a safety point of view. Ionising radiation can break chemical bonds and so has an obvious way to cause damage to your body - how much depends on the energy, how much radiation you absorb and where in your body it gets to. Both X-Rays and particles from radioactive material are ionising, as is the ...

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It is well-known that x-rays are blocked by metal. [Ref: Kid's Science] Obviously the doctor wants to look at your internal organs, unobscured by a fuzzy outline of your house keys and pendant. So, the sign is requesting that you removing metal items from the external parts of your body, to allow visibility to the internal parts. (MRI is a totally ...

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Black holes are formed from collapsed supermassive stars. If a black hole ends up completely isolated then it will be very black. However, many stars are binaries. Moreover, within dense globular clusters stars can often pass very close to other stars. Just as with stars, when a black hole is near enough to another star it can collect matter from it. Black ...

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I believe most of the em-spectrum from a nuke is low energy. So when you take a photo you get a lot of visible light and heat, and only small amounts of high energy radiation on your film. Also the lens might be transparent to visible light, but non transparent to high-energy em-waves. Edit: just found http://www.fas.org/nuke/intro/nuke/thermal.htm It ...

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I don't believe X-ray diffraction machines focus the X-rays. Generally you want to put them in along a straight line and detect them undisturbed from the sample. The straight line input beam is just a source an energy selector and a slit (unless the machines have got a lot more complex) The Wolter mirrors used in telescopes are because you only have very ...

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http://en.wikipedia.org/wiki/Electron_crystallography gives a pretty good comparison of the two. Basically electrons are much more strongly interacting than X-rays, so they are restricted to very small samples. In a previous life I used electron diffraction on mixtures of sub-micron crystals to identify what was present in the mixture. This would have been ...

3

I think there are two questions here. How do you focus high energy photons and how do you detect them. Generally detecting high energy photons isn't a problem. They have lots of energy (!), even measuring their energy directly as you collect them is pretty straightforward. So you don't need spectrographs in the same way as for visible light. Focussing ...

3

First of all terminology: When physicists speak of radiation they primarily speak of electromagnetic radiation. When health physicists speak of radiation they include radiations of other types, alpha and beta and neutrons in addition to gamma and xrays. They have developed a system where radiation is given in Becquerel ignoring the particular source. So ...

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In wikipedia there is an extensive article about x-ray detectors and one on gamma ray detectors. Detectors are calibrated to work with specific frequencies and though there will be some effect from a gamma ray source on an x ray detector, and vice versa, to make sense of it one would need the proper calibration. Now if you are asking whether when luggage ...

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Technology has evolved a bit compared to what was described by Martin Beckett. Many powder diffractometers still use the setup he describes, but mirrors are becoming more and more common at laboratory powder diffractometer sources. However, these mirrors do not aim to focus the beam, they collimate the beam (try to make sure that as much as possible of the ...

3

Exactly how and to what extent diamond shows up in x-rays depends on factors such as type of x-ray apparatus, size of diamond, orientation and so on. Carbon has an atomic mass of 12. That's fairly low. Diamond exhibits a bunch of unique properties such as extreme hardness, high thermal conductivity and chemical inertness. In terms of X-ray windows ...

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I guess the idea here would be to make something like a ring cavity for ordinary light, where the light is bounced around a closed loop. Which is something you see done in dye lasers, and has probably been used to do laser spectroscopy at some point. The problem with this is that if your deflection angle is a few milliradians, then you would require ...

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I finally found a source; according to Peter Nollert, ice rings are located at: 3.897 Å, 3.669 Å, 3.441 Å, 2.671 Å, and 2.249 Å. My frame seems to be missing one of the three 3 Å rings, but the 2 Å rings seem plausible.

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When you do diffraction, $\theta$ is the angle of incoming EM wave, as well as the angle of difracted EM in regard to Bragg's planes. So the total change in angle of the EM wave equals $2\theta$. See images at http://en.wikipedia.org/wiki/Bragg%27s_law. If this is not the answer you're looking for, maybe you should specify your question more clearly. (I ...

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Yes the refractive index of a material depends on wavelength. This phenomenon is called dispersion. In fact, it's precisely this phenomenon, for example, that causes prisms to separate white light into its constituent colors. Since each color refracts a different amount when they enter the material, the colors separate.

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There do not exist materials made of antimatter, so even though they would behave completely symmetrically to the corresponding matter materials, the fact is irrelevant. Dark matter reacts only with gravity, and X-rays are electromagnetic waves. To all intents and purposes, as far as possibility of measurements, dark matter is transparent to X-rays, since ...

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The question can be rephrased as "is there any form of matter that does not absorb X-rays?", because objects only appear on an X-ray plate if they've absorbed some of the radiation. Anything with electrons in it, i.e. all normal matter, will absorb X-rays to some extent. I think the interaction cross-section for photons and dark matter is effectively zero ...

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I would add this as a comment to the previous answer, but my starter-repuation precludes me from doing this. So, here is my refinement of Karsus Ren's response. Compton's formula (and 1923 paper) were about x-ray scattering from free electrons. In 1928, DuMond published a paper showing that for Mo K-alpha x-rays scattered off of beryllium, in addition to ...

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Found this for you: http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/compdat.html. The formula for Compton scattering assumes a free electron initially at rest. In reality, electrons have thermal motion, so only the peak value corresponds to the formula. In addition, electrons are bound by electromagnetic force. Electrons in the inner shell will have a ...

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The distinction is that the physics for detection of x-rays (hard and soft) and gamma-rays is different. For gamma-ray detection, Compton scattering will allow you to determine the direction of the incident photon by tracking the recoil electron, combined with the scattered photons direction and energy. The Compton recoil electrons can be tracked by ...

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For the $\theta : 2\theta$ goniometer, the X-ray tube is stationary, the sample moves by the angle $\theta$ and the detector simultaneously moves by the angle $2\theta$. At high values of $\theta$, small or loosely packed samples may have a tendency to fall off the sample holder.

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X-rays In order to make metal radioactive one have to turn it into another element or isotope. This can be performed only with high-energy particles (including photons). X-rays can be produces if an electron enters metal with very high speed in two ways: deceleration radiation (Bremsstrahlung) an atom absorbs part of the electron's kinetic energy, moves ...

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The wikipedia article covers what is happening pretty well: While light atoms have binding energies on order of a few $\text{eV}$, the binding energies of inner shell electrons on heavy atoms can be hundreds of $\text{eV}$. If anything happens to remove a tightly bound inner-shell electron (say a interaction with a high energy electron or other ionizing ...

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Yes, the Bremsstrahlung photon's energy is taken from a diminishing electron's kinetic energy. Because the typical energies in Brehmsstrahlung are at least of order keV, it's unlikely that the process of deflection slows down the electron exactly for the electron to sit in a bound state but of course that some electrons do and electrons interacting with ...

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