The property of some materials by which individual atoms decay, emitting energy or particles often transforming into different elements in the process.

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XP Decay mode of radioactive nucleus

The decay mode of Carbon-8 is listed as 'XP' in this table. None of the references I looked at listed XP as a decay mode. What is it>
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Is there a direct relationship between an isotope's neutron count and radioactivity?

In my textbook, it lists isotopes of Carbon: C-12, C-13, and C-14. It noted that C-14 is radioactive (C-12 and C-13 are not). Is there a direct relationship between the number of neutrons and an ...
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Decay of Cobalt-60 isotope

How does the Gamma decay of Cobalt-60 occur? Motivation: A research team led by D. Habs made contributions to our understanding of the gamma decay of Ca-40 and Zr-90: ...
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Program for radiation and toxic hazards

I worked in my masters thesis with $^{87}Rb$ and $^{40}K$, really small beta emitters. But there are so many other things around in the lab, that I want to keep track on all the things I might get in ...
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How do we know that internal conversion creates no intermediate photon?

I've read, from several sources, that in internal conversion -- an excited electron transferring its energy to another electron which is then emitted -- no intermediate gamma radiation is produced. ...
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Why are alpha particles made of 2 protons and neutrons?

When experiencing alpha decay, atoms shed alpha particles made of 2 protons and 2 neutrons. Why can't we have other types of particles made of more or less protons?
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Earth's beginnings and early years, Re radioactive decay or not

It is said that the Earth and solar system are 4.6 billion years old. Presumably this date is achieved from radioactive decay. If this is the case, since most of the radioactive elements would have, ...
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How to calculate gamma radiation shielding?

A device emits 0.2 ╬╝Sv/h of gamma rays. How thick does an aluminum sheet need to be to completely stop radiation from coming out ? What equation is to be used to calculate this ?
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219 views

How was Be-8's Half-Life of 7E-17 Second Determined?

Radionuclides occur with half-lives in a vast range of over 37 magnitudes as listed in this site. In question 7584, Lubos Motl explained how Gyr half-lives were determined. This method doesn't appear ...
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Problem on nuclear physics radioactivity [duplicate]

Possible Duplicate: How do we know that C14 decay is exponential and not linear? Please help me solving this problem. Find the half life period of uranium-238,if one gram of it emits ...
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234 views

Can stable nuclei theoretically fission through quantum tunneling?

As I understand it, an unstable nucleus is going to randomly fission because the forces binding it together are momentarily weaker than the electrostatic repulsion of the protons. Given that some ...
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363 views

Island of Stability

When I was much younger, I remember being fascinated by the thought of an Island of Stability at very high atomic numbers. However, I have not heard much on this and I was wondering Did this idea ...
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Why is beta negative decay more common than beta positive?

In simple terms, why is beta negative decay more common than beta positive? I know it's something to do with occuring inside/outside the nucleus - but I can't find a simple, easy to understand ...
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93 views

Creation of Nuclear Isomers

As I understand it, if a nucleus is excited with energy exceeding its ground state, it releases energy via gamma radiation. An example would be technitium 99m, a medical tracer with a 6 hour half life ...
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718 views

can radiocarbon dating be used on living things?

I have been going through a wiki article about worlds oldest living creature. As a matter of fact its a plant, a shrub to be precise. Wiki says that the plant age was determined by carbon dating. But ...
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How do we know that C14 decay is exponential and not linear?

In my previous question I asked Please explain C14 half-life The OP mentioned that I was thinking of linear decay and C14 was measured in exponential decay. As I understand it, C14 is always in a ...
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Please explain C14 half-life [duplicate]

I understand that C14 decays at a given rate. I also interpret this to mean that 100% of the atoms of C14 in an object will all decay at the same right, individually. So if I have 4 C14 atoms, will ...
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1k views

Effect of temperature on radioactivity?

I'm researching the effect of temperature on uranium radioactivity, however I can't find any solid empirical evidence to prove the notion that temperature does not affect radioactivity. Can anyone ...
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13k views

What did Marie Curie do for atomic theory?

There appears to be a distinct lack of agreement in the physics community on what exactly Marie Curie did for atomic theory. Many journals state that Curie was responsible for shifting scientific ...
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radioactive decay in molecular constituents [duplicate]

Possible Duplicate: What happens to chemical compunds that include radioactive nuclei, when those decay? Suppose a radioactive atom, which is incorporated in a molecule, decays? What ...
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485 views

Significance of isolation of radium? [duplicate]

This is an extension of my previous question here. Marie Curie isolated radium in 1903, which paved the way for the development of the theory of radioactivity. In regards to the techniques she used ...
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Work of Marie Curie?

I've been reading about the work of Marie Curie recently after a friend filled me in on what she did (never having had much of an idea previously) and it's all very interesting. What I can't ...
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What other shielding material than lead is effective against gamma rays?

As the question in the title states I am wondering what material can be effectively used to shield gamma rays apart from lead? I believe concrete is often used, but it is nowhere near as effective as ...
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408 views

Nuclear decay rate affected by sun and quantum randomness

If nuclear decay rate were affected by sun, then emission probabilities would be subject to sun state and its influence, so quantum randomness would depend on it, Would it still be truly random? One ...
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188 views

Does the Standard model allow for radioactive decay prediction? [duplicate]

Possible Duplicate: Predicting Decay Rates via the Standard Model More specifically, does (any) current theory allow for approximate or exact predictions of atomic decay rates and types ...
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Is there a way to decrease the rate of nuclear Beta decay?

In that question and its answers it was mentioned that you could trigger radioactive decay by bombarding atoms with gamma rays of the right energy level (there may be other solutions I do not know ...
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118 views

experimental setup to measure Center-Of-Momenta of products from spontaneous radiactive decay

This question is an attempt to complement this other question about fluctuations in radiactive decay. This question is completely experimental though: in general, suppose i have certain sample of a ...
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The vacuum as trigger

Do the apperance in the atomic nucleus of virtual matter-antimatter particle pairs play a role in the random nature of radioactive decay?
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strange modulation of radiactive decay rates with solar activity

Recently i found out this uber strange article about nuclear decay rates being somehow showing seasonal variations with a high correlation with sun activity. Two very precise questions: 1) has this ...
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Can one see radioactive substances with an X-ray detector?

I was wondering the other day an X-ray detector (like the ones used at airports) can detect gamma-rays lets say from a sample of uranium. I know its all electro-magnetic waves but I'm really unsure ...
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Why do they consider radioactive matter with long half lives more dangerous than matter with a short half life?

The title says it all. For example why is plutonium considered more dangerous than radioactive iodine?
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Radioactive nuclear fuel?

I suppose this is a not-too-bright question but, in a nutshell: why are nuclear fuels radioactive? With this I mean, which is the connection between being a fissile (or fertile, for that matter) ...
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338 views

Dangerous dose of I-131?

I was searching a lot and could only find dosages for curing cancer and allowed emission, but no Iodine-131 dose that could be connected with increased thyroid cancer risk (like, 10mSv is the ...
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What happens to chemical compunds that include radioactive nuclei, when those decay?

Say you have a chemical compound made up of one or more radioactive nuclei. If the nucleus decays, does the compound? Possible outcomes I can think of: the compounds continues to exist if a ...
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Gravity and Planetary Differentiation

During solar system formation, many bodies achieved hydrostatic equilibrium, a spherical shape where their self gravitational force was balanced by internal pressure. Many also achieved ...
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What needs to happen for one to ingest radioactive particles and how likely is this?

There are many stories about radioactivity and the relative danger of it in the news lately, but very little actual information. The radioactivity levels around Fukushima Daiichi are high, but seem ...
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562 views

Predicting Decay Rates via the Standard Model

Question 7584 illustrated a procedure to forecast the decay rates of isotopes with known long average lifetimes. Lifetimes of the many U isotopes vary from micoseconds to gigayears. F has only one ...
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Iodine isotope question

Quick question for the nuclear engineers/physicists out there Where does I-134 come from? I cant find it in any of the charts of standard decay products of Uranium fission, but there is tons of the ...
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How do we know that some radioactive materials have a half life of millions or even billions of years?

If a radioactive material takes a very long time to decay, how is its half life measured or calculated? Do we have to actually observe the radioactive material for a very long time to extrapolate its ...
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126 views

Detailed logical steps to show experimentally that radioactivity ionizes air?

Suppose one knows almost nothing about the nature of radioactivity (like the discoverers of this phenomenon). What are the detailed/rigorous logical steps/arguments to show experimentally that ...
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Iodine-131 half-life and reality

Iodine is a chemical element with symbol I and atomic number 53. There is currently a lot of discussions regarding radioactivity in Japan, and iodine-131. Iodine-131 has a half-life of 9 days. Does ...
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561 views

Can electricity transfer radioactivity?

If a cable used to power something is exposed to a radioactive source will it over time make the entire cable radioactive?
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Since radioactive material decays how is it possible that there is any left after 4.5 billion years?

I was not able to find an answer for this question... Some radioactive elements have half-life measured in thousands of years and some others even in millions, but over 4.5 billion years all the ...
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Alpha Beta Gamma Biological Impact

Assume that alpha & beta particles and gamma photons each reach skin at the same energy. It's known that they penetrate most deeply in order by gamma, beta and alpha. How would they compare in ...
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Long time deviations from exponential decay in radioactivity

Are there any examples of common substances whose decay is not exponential? We're used to thinking about radioactivity in terms of half-lives. This is a concept that makes sense only for a decay that ...
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Is there any thing other than time that “triggers” a radioactive atom to decay?

Say you have a vial of tritium and monitor their atomic decay with a geiger counter. How does an atom "know" when it's time to decay? It seems odd that all the tritium atoms are identical except with ...