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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Gamma Spectrum: What is causing this behavior?

In my radiation detection lab we're identifying a unknown source, based on the gamma spectrum it's an activated gold foil. You can clearly see 4 peaks: 411.78 keV (Au-198), 675.93 keV (Au-198), 823.51 ...
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Would a matter-antimatter explosion cause fallout?

I know matter and antimatter annihilation release a lot of gamma rays which are considered ionizing radiation if I am not mistaken. But what if the explosion happened on the surface of the earth, ...
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70 views

Are there any radiation emitted from the cameras? [closed]

Do modern video cameras emit any kind of radiation? If so, what range of frequencies they have? I was wondering if we can detect any radiation so any help regarding detection will also be appreciated. ...
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Proton energy distribution after Si layer

I've been using SRIM to get an approximation of the energy distribution that a beam of monoenergetic incident ions will have after a thin layer of silicon. However, for my purposes it would be better ...
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2answers
59 views

What is the distribution of energy between the alpha, beta and gamma particles emitted in nuclear fallout per one RAD?

I have been trying to find a relation to be able to convert from RAD to REM. What I found is that I need to know the "quality factor" as some sources call it, which is the effect of different ionizing ...
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24 views

Will the background radiation get “dimmer”? If so when will it be “turned off” [duplicate]

This video http://youtu.be/_mZQ-5-KYHw talks about the background radiation which we can observe today. It's from the beginning of the universe and has traveled so long that the expansion of the ...
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1answer
27 views

Index of refraction appearing in the radiative transfer equation

In this publication the Radiative Transfer Equation (RTE) (eq. (7)) contains the following emission term: $$n_i^2\kappa_{d,i}L_{b,i}(\mathbf{r})$$ where $n_i$ is the refractive index of component ...
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95 views

How damaging is light? [closed]

On Surely You're Joking Mr Feynman, when talking about the Trinity test, the author states: the only thing that could really hurt your eyes (bright light can never hurt your eyes) is ultraviolet ...
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1answer
76 views

Use of fission products for electricity generation

Why can't we use fissions products for electricity production ? As far has I know fissions products from current nuclear power plants create enough 'waste' heat to boil water; and temperature ...
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4answers
2k views

Why aren't betavoltaics and alphavoltaics batteries widely used?

Betavoltaic batteries are devices which creates electricity from beta radiation of a radioactive material. Alphavoltaics operate similarly, using alpha radiation. The concept was invented roughly 50 ...
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1answer
28 views

“Radiative” particle decay?

This might be a very simple question, so sorry. I have encountered the expression "radiative particle decay" quite a few times now, and none of the sources ever explain what they mean by radiative: I ...
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2answers
66 views

Leakage of X-ray radiation

Suppose a sample of strontium-90 is stored in a lead container with lead walls. It is know that X-ray radiation may be detected outside the lead container. After some discussion with my peers, it ...
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Maximum electron momentum in $\beta^-$-decay

This should be easy, but I think I have a mind-block... For $\beta^-$-decay, what is the maximum possible momentum for the electron? The two equations I can use are conservation of energy and ...
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124 views

Radiation emission and absorption

Any object can emit and absorb radiation and the power of emission can be represented by the Stefan-Boltzmann law: $$P=A\epsilon\sigma T^4$$ In many texts the net power radiated is the difference ...
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1answer
37 views

Help understanding this differential equation of a varying electromagnetic field [closed]

I'm reading some lecture notes (we're studying blackbody radiation and are approaching Planck's formula) but I'm struggling to understand exactly what's being said. So the lecture notes read as ...
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3answers
85 views

Is the amount of radiation you receive in space constant regardless of velocity?

I'm only in high school, so this will probably have fatal flaws. So basically in space, there is bound to be stray radiation, whether from the stars, or cosmic background, floating around right. And ...
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Why can Hiroshima be inhabited when Chernobyl cannot?

There was an atomic bomb dropped in Hiroshima, but today there are residents in Hiroshima. However, in Chernobyl, where there was a nuclear reactor meltdown, there are no residents living today (or ...
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1answer
33 views

Model to convert radiation data from one tilted surface to a different one?

I have measuring data of global radiation on a tilted surface (a solar collector surface). Now I need to do 2 things: split the tilted global radiation into its diffuse and beam parts calculate ...
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1answer
59 views

Why is the graph of CMB/black-body radiation asymptotic?

Speaking of this graph of blackbody radiation, I see that the graph goes to 0 asymptotically: As we go to higher and higher frequencies, the energy of a single photon becomes increasingly high. ...
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22 views

Beta plus decay [duplicate]

I think I understand beta minus decay: A nucleon loses mass and this mass is converted into an electron and an electron anti-neutrino. Correct? (I imagine there might be some kinetic energy too but ...
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31 views

Beta plus decay…explain one thing [duplicate]

Can anyone please explain how, in beta plus decay, a nucleon can gain mass by changing from a proton to a neutron? Where does it get the extra mass from? Does it convert energy in some way? Does ...
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2answers
263 views

Will a microwave heat sand?

I want to cook Turkish coffee on heated sand at school. I have difficulty accessing some easier method of heating, so I was going to try to heat sand in a microwave. It was then pointed out to me that ...
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1answer
95 views

Cobalt 60 beta decay

In the beta decay of an atom of Co60, the radiation you would expect is one or two gamma rays, plus an electron plus an electron neutrino (and in the nucleus Ni60+, if I understand it well). However, ...
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1answer
49 views

What's wrong with this temperature-in-space calculation?

I'm trying to calculate the steady-state temperature of a body in space, but my numbers are coming up much too small. For example, for a 1-meter cube, I'm getting a temperature of 194 K (or -81 C). ...
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1answer
324 views

Why does electron move closer to the nucleus when it emits light and not vice-versa?

The book tells me that electrons move more close to the nucleus when emission occurs and it moves far away from the nucleus when absorption occurs: why it's not vice-vers? As I understand, the ...
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3answers
126 views

Radioactive decay - What mechanism decides when an unstable nucleus decays?

My first question on Stackexchange (if it is formatted wrong or something please tell me so I know in future) - here it is: Given an unstable nucleus (exactly which nucleus is not particularly ...
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4answers
491 views

Why are alpha particles such a prominent form of radiation and not other types of nucleon arrangement?

It is said in many textbooks that alpha decay involves emitting alpha particles, which are very stable. Indeed, the binding energy (~28.3 MeV) is higher than for $Z$-neighboring stable isotopes. But ...
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480 views

Is data which rides on the carrier frequency dangerous?

My understanding of broadcasting data via electromagnetic radition is, that the data "rides" on a carrier frequency on which it is radiated. I am aware of the fact, that those carrier frequencies are ...
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2answers
86 views

Why black body radiation is all over the frequency range

I was studying black body radiation and how quantization of energy solves the problem of ultraviolet catastrophe. But I have a very fundamental doubt. A black body can be assumed as a cavity with a ...
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3answers
2k views

How can there be heat in a vacuum?

I keep reading in the Physics World focus issue on vacuum technology about scientists creating high temperatures in the vacuums etc. If heat is caused by thermal energy being radiated from particles ...
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80 views

What did recombination look like?

I recently remembered that someone worked out what the big bang sounded like and that got me thinking... About 377,000 years after the Big Bang, electrons became bound to nuclei to form neutral ...
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93 views

internal conversion and the electromagnetic force

I have read that the mechanism behind internal conversion, in which a nuclear transition leads to the ejection of an electron in one of the lower atomic orbitals, is related to the fact that the ...
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1answer
49 views

What does a supernova look like at its peak luminosity?

I know that in some types of supernovae, the cause of the increased luminosity is the radioactive decay of certain elements ejected during the explosion, so a question came to my mind. If the ejected ...
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42 views

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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3answers
488 views

How can blackbody radition be explained by quantization?

I don't understand why quantization makes a peak on the blackbody radiation curve (so there is no UV catastrophe) and the relationship between that peak and quantization concept. When the blackbody ...
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1answer
58 views

Need help in identification of formula [closed]

i would greatly appreciate it if someone could provide me with the concept to learn about this equation
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1answer
78 views

What can make signal triangulation tricky?

Usually, when you're trying to find a source of whatever signal, you move around the source and then calculate the position using triangulation. I'm specifically talking about low frequency signals, ...
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2answers
47 views

Function to fit solar radiation data

I have ground-level radiation data of solar incoming radiation from a radiometer (cosine collector) measured along the day. In the following plot you can see PAR irradiance (ie visible light) in Watts ...
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1answer
38 views

Calculate transparency from Beer-Lambert Law

I want to calculate a transparency parameter for a superposition of several volumes containing media using the Beer-Lambert Law, which states that $$I/I_0=exp(-\tau)$$ where $I$ is the transmitted ...
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26 views

Energy of black body radiation [duplicate]

Does radiated energy of black body radiation due to the transition of electrons to higher energy state? or due to the increasing vibration of atoms themselves?
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1answer
181 views

Maintaining local thermodynamic equilibrium (LTE) in radiating gas with a broad atomic transition line

Definitions / Background In LTE, Kirchoff's law for radiation holds: $$ \frac{j_{\nu}}{\alpha_{\nu}} = B_{\nu} (T) $$ where $j_{\nu}$ is the specific radiative emissivity, $\alpha_{\nu}$ is the ...
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1answer
59 views

Is it possible to generate electric energy from the radiation of radioactive materials

I wonder if it is possible to generate electric energy from the radiation of radioactive materials like nuclear waste? If it is then wouldn't that also mean that it could be used as an energy source ...
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2answers
286 views

How does quantization solve the ultraviolet catastrophe?

I understand how classical physics leads to the UV catastrophe. But I cannot understand how quantization solves it. How can quantization prevent the body from radiating a lot of energy? I know ...
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1answer
351 views

Is there any difference between a proper photon and a photon of thermal radiation?

Does a thermal photon radiate spherically whereas a photon radiates in a circle/beam? How do you tell a thermal photon of, say 3 eV, from a photon of light?
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171 views

Does blackbody radiation work like this?

In a blackbody object the photons are reflected back and forward. If I heat up the the blackbody object with microwaves or other types of photons the electrons in the wall would vibrate. When the ...
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235 views

How Does Lead Block Radiation

How is it that lead can block radiation, and things are lead lined. In the Indiana Jones 4 movie he climbs inside a lead-lined fridge and he somehow survives the blast and radiation?
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2answers
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How can heat turn into light

I am confused about how hot surfaces can radiate light to their surroundings. When I shine a light on a surface the light turns to heat spontaneously, and when I leave that hot surface it radiates ...
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5answers
564 views

Can we say there are 2 EM radiation types?

EM radiation seems to come from two different sources: According to the Maxwell, by acceleration of electrons According to the Bohr, by jumping of electrons between energy levels? Are these two, ...
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5answers
76 views

Is the plasma state always visible?

All the examples of plasma I have come across are visible. Is there any plasma which is not visible? For example, during a dark lightening we don't see the radiation because its gamma radiation. Is ...
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How does radiation shielding using absorbing materials work?

I understand that, for example, a thick enough sheet of lead can absorb gamma radiation, but I want to understand what actually happens at the molecular/atomic/subatomic level. Also, can the same ...