Questions tagged [radiation]
Radiation is a process in which energetic particles or energetic waves travel through a medium or space. The particles or waves radiate (i.e., travel outward in all directions) from a source.
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On the right-angled fork track of alpha particles
In high school we were told that the idea "alpha particles are actually helium nuclei" came from observing the right-angled fork track, produced by placing an alpha source in a diffusion cloud chamber ...
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Why bulk of HPGe detectors is doped?
When I am looking at schematic diagrams of HPGe gamma spectrometer detectors (like this Ortec GLP one), it is often mentioned that bulk of Ge is doped. In this example - P-type doped. Is there a ...
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"Single-shot" Heat engine efficiency limits
The sun is 5778K and Earth is ~290K. Using the sun as the hot reservoir and earth as a cold reservoir we get 95% Carnot efficiency. However, the solar power efficiency limit is only 86%, see: http://...
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Surface UV exposure with cooler star
If the sun's surface was ~ 4000K (and earth closer to compensate), the UV component of the radiation would be less. However, UV makes ozone via photolysis of oxygen. Also, the stratosphere would ...
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Gravitational wave flux in Effective One-Body (EOB) models
I'm working for my M2 internship on gravitational waves in effective one-body approach, and I'm struggling in understanding how they compute the non-conservative flux from GW radiations. Most of the ...
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Shield gamma/X-ray/ultraviolet radiation without blocking radio waves
I was theoretically considering building an airtight enclosure that shielded the insides from gamma/X-ray/ultraviolet radiation but did not block radio waves (so that communication would not be ...
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Why gravitational waves can only be generated by a time-varying quadrupole moment of the mass distribution?
The (rather old) source I dispose of "Sexl, Urbantke : Gravitation and Cosmology" describes the radiation of gravitational waves only rather sketchy. So why gravitational waves are only generated by ...
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Frequency spectrum of bremsstrahlung
I have tried to find a method to derive the spectrum of the emitted radiation of accelerated relativistic charged particles but I've never found such a method in any books. Does anyone know a method ...
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Do Solar Cells Regenerate After Exposure to Ionising Radiation?
In the past, plenty of research has been done on the effects of ionising radiation on solar cells. This is due to the importance of high efficiency solar cells for electric spacecraft propulsion. Such ...
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Interaction with Gravitational Radiation
I have a question about hypothetical gravitational radiation. To put it simply, is there any sort of material or field or other force which can interact with it? I'm thinking about lenses and mirrors ...
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Equivalent Dose absorption from Na22 source
No idea what exactly the rules are or how I should ask this question, but here's the verbatim quesiton:
"A Na$^{22}$ source has an activity of 100 $ \mu $C. If you handle the source, how big is the ...
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Trouble justifying calculation of force on a sphere due to radiation pressure
I am attempting to calculate the force on a sphere in a plane wave of light where the light has intensity $I$. My calculations have concluded that, regardless of whether or not the sphere absorbs or ...
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Effect of Background Radiation on a Transmitted Signal
I'm coding a basic simulation of using error correcting codes to transmit data from a satellite back to earth. I'm not sure what to set the "noise level" to. Let's say a satellite orbiting Mars ...
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A problem concerning the change of temperature and spectrum of a filament
The spectrum of a filament has been given before, the left one having the lowest temperature, the middle with a medium temperature and the right one with the highest. My question is this: Why does the ...
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Are scalars starting at around 1300 MeV analogous to some kind of sound in the vacuum glue?
Are scalars starting at around 1300 MeV analogous to some kind of sound in the vacuum glue?
Background:
There are scalars starting at around 1300 MeV which are probably some combination of glue-...
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