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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How to calculate gamma radiation shielding?

A device emits 0.2 μSv/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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574 views

Why is radioactive decay dependent on amount of substance available?

Radioactive decay is an attribute of unstable nucleus. When we represent it in equation, we don't involve any macroscopic attribute of substance. But still, rate of radioactive decay is proportional ...
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86 views

Why is there an emission of gamma rays?

When a spontaneous radioactive reaction happens, there is an emission of gamma rays (in most cases) What causes this emission?
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101 views

Harmlessness of a pure alpha decay particle

From my high school physics class I remember that there are some particles which exhibit pure alpha decay (i.e. alpha decay to there stable isotope), like Po-210, Po-211 and Bi-209. What I also know ...
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5answers
337 views

Thorium radioactivty vs Uranium radioactivty nuclear power

May i please open this question by asking that if you intended to answer this please could you provide links based on your answer. I have read ( and posted one ) on thorium and a lot of the answers ...
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958 views

Artificial planetary magnetic field

I wonder how difficult it is to create an artificial planetary magnetic field with generators? What power they would need? The question is inspired by thinking about possible colonization of ...
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119 views

Radioactivity and quantum superpositions

In the Schrödinger's cat experiment 'there is a tiny bit of radioactive substance, so small that perhaps in the course of the hour, one of the atoms decays'. The rest of the experiment magnifies this ...
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1answer
50 views

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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1answer
193 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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217 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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132 views

Radioactive decay / binding energies

If my understanding is correct, the binding energy determines a nucleus' stability and the greater the binding energy, the more stable the nucleus (e.g iron-56). The mass of the sum of nucleons that ...
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1answer
137 views

Is sub critical plutonium “safe” to handle?

Apparently, in Los Alamos scientists handled sub critical masses of plutonium (for example the demon core) with little or no protection. Richard Feynman and others mentioned that plutonium spheres ...
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88 views

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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117 views

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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89 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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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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2answers
511 views

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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1answer
94 views

Conversion of energy to mass with radioactive decay

Consider the following problem: The nuclei of Am-241 decay by the emission of $\alpha$-particles with a kinetic speed of $8.8 \cdot 10^{-19} J$. In a certain source of Am-241 there are $ 4.0 \cdot ...
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94 views

Probability density of detection of collinearly emitted photons in two detectors

Update: As proposed by @dmckee, I added equation numbers and improved the display of some equations. The answer by @Trimok inspired me to look at coordinate systems which are not specific to the ...
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Besides transmutation, is there any way to “speed up” the decay rate of radioactive material?

I'm well aware of transmutation as a way to effectively make radioactive material decay faster, however that isn't really what I mean. Doing a quick Google search I found references to several ...
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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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58 views

Can radioactive energies become electromagnetic

I am trying to learn about radioactive energies and wonder if, because these also seem to come under the topic of radiation, can these energies become electromagnetic. I'm pretty much a beginner, so ...
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376 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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2answers
109 views

Was the early Earth radioactive?

I've been reading of the (surprising) fact we are uncertain on whether there is nuclear fission in the center of the Earth or not (yet we know so much detail on structures at the other end of the ...
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1answer
61 views

Is radioactive decay spontaneous or random?

When the count rate of a radioactive isotope is measured, the readings fluctuate. Do the fluctuations demonstrate the random nature of the decay or the spontaneous nature? (This question was asked in ...
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199 views

Alpha Decay or Fission

In a quiz contest, I came across the following question: What is the term used to describe the splitting of a heavy nucleus into two lighter nuclei? Two options provided were: a) Alpha Decay b) ...
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1answer
38 views

Why does Se-82 undergo double beta decay?

Looking at the decay chain, I saw it undergoes double beta decay. How is it feasible for something to undergo a simultaneous double decay?
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Relativistic Mass including exponential decay

So from what I gather, relativistic mass = $m_0\gamma$ where $\gamma$ is the lorentz factor. So if i have a mass that is .5 at rest then it is safe to say that the relativistic mass will be 1 if it ...
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414 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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114 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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Time scale when measuring total activity from radioactive sample

I have measured the total activity from a radioactive sample during an experiment by counting the number of decays happening in 3 seconds intervals. I got data as: Time bin: 0 1 2 3 4 5 6 7 ... ...
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1answer
20 views

Differentiating between mass number (A) and activity (A) in a nomenclature/glossary

I'm not sure if this is the best place to ask this question, but as it's related to the terminology of nuclear physics I thought it would probably be a logical place to start. I'm currently writing ...
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19 views

How does beta+ decay actually occur? [duplicate]

I'm having difficulty in understanding beta plus decay. How can a proton which has slightly less mass than neutron transform into a neutron, positron and neutrino? Form where does the extra mass for ...
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1answer
46 views

Using $A = {\lambda}N$ to find when a the amount of a radioactive source becomes constant

The question and mark scheme I will write in bold and my own thoughts in normal sized text. I'm told that: When a $\bf{_{92}^{235}U} $ nucleus is exposed to free neutrons it can absorb a neutron. ...
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49 views

Recover activity from photo at Fukushima

This photo was published at stern magazine online. I wonder which information about the physical quantities could be reconstructed or computed given this photograph, the exposure time, and the ...
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697 views

How do you calculate the equivalent absorbed radiation dose from activity, type of emission, and the energy of the emission?

I have a sample of U-238 of which my Geiger counter detects beta activity at 700 events per second. Based on the counter's efficiency of 98.6% for U-238, the activity would be about 710 becquerels, I ...
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457 views

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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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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158 views

How can radioactivity change depending on the number of nuclei? [closed]

I came across this problem. Please help me solve it. A radioactive sample S1 having an activity of $5\ \mathrm{\mu Ci}$ has twice the number of nuclei as another sample S2 which has an activity ...
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1answer
360 views

Does the Earth's revolution around the Sun affect radioactive decay?

Premises: The radioactivity is either hastened or slowed inside a fast moving aircraft. Speed of fastest aircraft: 3,529.6 km/h. The earth's revolution is: 107278.87 km/h. The earth's ...
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1answer
29 views

Does KI have to be a salt of stable I-127 isotope?

I was recently watching a TV show where some people exposed to radiation were asked to take KI. I googled for the information and discovered this and also the Wikipedia article. From what I read, I ...
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1answer
667 views

Nuclear reactions conservation laws

I'd want to know the basic rules to apply the conservation laws in nuclear reactions (nuclear fusion, nuclear fission, radioactive decays, etc.) to determine parity and angular momentum of the ...
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43 views

Where can I find a device or how can I make a device that measures only Alpha particles?

Are there special muller tubes that only measure alpha for example?
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Energy Question

Carl throws 100 g of Bohrium-262 (Half life: 0.10 seconds, undergoes alpha decay) to Sukhdeep with a initial horizontal velocity of 20.0 m/s at an initial height of 2.00 m above the ground. What is ...
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448 views

How is tritium illumination possible without negative health effects?

Turns out there's tritium illumination - a tiny very strong plastic tube will be covered in phosphor and filled with tritium. Tritium will undergo beta decay and a flow of electrons will cause the ...
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1answer
146 views

How to make neutron activation analysis online or with free software?

i want to make a neutron activation analysis for different crystals. (MnWO4, TbMnO3, and others) how can i do this with free or open source software? Can someone recommend a online calculator for ...
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1answer
31 views

What is the theoretical wattage output of a Tokamak fusion reactor?

By that I mean the complete radiative wattage of any type of energetic radioactivity or electromagnetic wave or even particle if that's what they output. My purpose is to compare this to the suns ...
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1answer
123 views

Mean stopping range of $\alpha$-particles in air

I did an experiment in university in which I determined how far $\alpha$-particles emmited from an $Am^{241}$ source penetrate into air. I want to compare my result to literature values but... I cant ...
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1answer
300 views

Inverse Square Law in Beta Radiation

Setup: A radioactive source is placed at alternating distances from a Geiger Counter. Counts per second for 10 different distances (each spaced 1 cm apart) were taken for preset times ranging from 200 ...
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77 views

Is the fraction of radioactive isotopes on the near side of the moon higher than on the far side?

As time passes more slowly in a region of space close to the source of a gravitational field, shouldn't the moon, which always has one side facing towards the earth, have a higher fraction of ...