Questions tagged [radioactivity]

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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11 views

Pressure stabilisation of radionuclei

Looking at explanations of neutron stars, the neutrons towards the center of the star are stabilised by the enormous pressure, and so don't undergo nuclear decay. I am wondering if this is possible ...
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Why can't I find the moment $t_1$ where the radioactivity is gone?

Let's say $t_1$ is the moment the radioactivity is gone: $A(t_1) = A_0 e^{-kt}$ $A(t_1) = 0$ since it's gone But then what? How do I find $t_1$? Since $A_0 e^{-kt} = 0$ then I can't "$\ln$" ...
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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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In neutrinoless double beta decay, what happens when the neutrino(s) is/are absorbed? Is a lepton released, as per usual?

Neutrinos are detected when they 'hit' a nucleus and are re-directed (z-boson) or 'create' a leptons that matches the type of neutrino.... What happens when the neutrino(s) in a neutrinoless double ...
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Is there any simple way to predict beta decay half lives?

Question For nuclides that decay by alpha emission, the Geiger-Nuttall law gives a simple and reasonably accurate estimate of the half-life. Essentially, one can model the alpha particle as a ...
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Can a radioactive atom be prevented from decaying if it's in a REALLY strong chemical bond?

So, based on this question, a molecule containing a radioactive atom will break when the atom decays. But suppose you need a lot energy to break the compound apart --- as in, more energy than the ...
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Does the halflife time of a radioactive material decrease if its temperature increases?

If at high temperatures atoms are more intensely interacting with each other or emitted photons that also could make the core vibrate. Is in these circumstances the radioactive material more likely to ...
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Would Cherenkov radiation be observed in Uranium glass?

I recently read about Cherenkov Radiation and the neat blue glow it creates in underwater nuclear reactors, and my understanding of it is that it occurs due to particles ($\beta$ particles in the case ...
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Radioactive secular equilibrium and the relationship between the half lives of the parent and the daughter nucleus

It's known that In nuclear physics, secular equilibrium is a situation in which the quantity of a radioactive isotope remains constant because its production rate (e.g., due to decay of a parent ...
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38 views

How does radioactive decay affect material properties?

If I leave a bar of a radioactive material (e.g. uranium-235) for its half-life time, how will the bar look after halving its mass? Will it: stay the same size, but be lighter? shrink in size as to ...
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Why does a collection of radioactive atoms show predictable behaviour while a single one is highly random?

Well, we know that it is impossible to say exactly when a radioactive atom will go on decay. It is a random process. My question is why then a collection of them decays in a predictable nature (...
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Radioactivity and half life

Does the process of decaying in radioactive elements occur every second? The equation consists of $\rm e$, so it must mean that decay due to radiation must occur every second, right?
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Electron Capture or K-Capture and Heisenberg's Uncertainty principle

I read about Electron Capture or K-Capture in radioactivity. There I found that the electron in the K shell is captured by the nucleus and as a result the atomic number of the element decreases by 1 ...
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Were alchemists right? [closed]

When I was in school, I learned about alchemists, a group of scientists who sought a way to convert other materials into gold. They were never successful, so whenever I studied or read about them, ...
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Examples of macroscopic systems with exponentially distributed lifetimes?

I was considering the statistical lifetimes of various light bulbs at first. However, upon further reading it seems that they tend to be approximately Weibull distributed with a shape parameter $k \...
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What does CC699 mean in reference to Plutonium? [closed]

I noticed that Plutonium storage containers often have cc699 written on them. A Google search for cc699 also brings up plutonium as the first page but I can't find any mention of cc699 on the page or ...
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If you could magically tweak the strength of nuclear force, would some radioisotopes decay faster and others slower?

As far as I understand, there are forces in opposition within a nucleus: the protons are pushed apart by their positive charge, but held together (along with neutrons) by the strong force. For a ...
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How will the possibility of tritium contamination decay be removed from XENONnT data?

The abstract of the new arXiv preprint Observation of Excess Electronic Recoil Events in XENON1T contains the following sentence: The excess can also be explained by $\beta$ decays of tritium, which ...
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Why is Polonium-210 more lethal than other radioisotopes? [closed]

So it takes a single microgram or less of pure Polonium-210 to be lethal. Which according to basically all sources makes it the most toxic material or at the very least the most toxic element. But why ...
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Why is long-term radioactive material so bad?

So i'm currently researching nuclear power and nuclear energy as it is a topic that has always interested me, but when researching nuclear fission waste, and hearing about waste that has a half life ...
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Activity of a radioisotope after an hour of irradiaton

Suppose that you irradiate a beam of monoenergetic alpha particles on a target. You can determine the saturation activity using Saturation activity = $\frac{R_a x \sigma \rho N_A}{A}$ But how do you ...
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Why Pb-210 is lost “as fast as” the creation through Ra-226 decay?

In a material about radiometric dating, it is said that: As fast as this background $\bf{_{}^{210}Pb}$ is lost by radioactive decay, new $\bf{_{}^{210}Pb}$ is created by the decay of $\bf{_{}^{226}Ra}...
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Estimating the energy output of a tritium watch

I was recently trying to get a very roughly obtained estimate for how much power my radioluminescent watch is giving off and the result was so low I wanted a second opinion. There are no official ...
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$\beta^-$ and $\beta^+$ $Q$ value issue

It's unclear to me why the following doesn't work when I calculate the $Q$ value for $\beta^-$ and $\beta^+$ decay. If we start with a parent nucleus $P_z$ with $Z$ electrons decaying through $\beta^-$...
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How to estimate exposure in Roentgens/hr from 99m Tc on a given distance?

I tried to find out how to calc it myself, but seems it's not something very straigthforward... I hope it's not a bad question, sorry if it is! So, this is known: It's 99mTc Let's assume it's point ...
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Why is this way of calculating mean life of radioactive atoms incorrect?

Suppose there are $N$ radioactive atoms and the half life of decay is $t$. Then after one half life the number of remaining atoms will be $\frac{N}{2}$. And so after each half life the number will be ...
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How do we observe that $\frac{dN}{dt} \propto N$?

I was learning how do derive the radioactive decay formula which starts with the experimental observation that the rate of decay is directly proportional to the amount of isotope present. i.e. $\frac{...
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Radioactive decay differential equations [closed]

I am trying to form a differential equation between two different isotopes, Uranium-238 and Thorium-234. The rate of decay of an isotope is proportional to the amount present. So that: $$ \frac{dx}{...
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Where could I find a reliable source that states all the existing radioactive decays?

According to searches on many sources on the web and books, I could merge informations to deduce that the general possible radioactive decay modes are the following: $\alpha$ (proof that this is a ...
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Is the so-called $\gamma$ radioactivity corresponding to the so-called $\gamma$ emission of the isomeric transition?

According to information on radioactivity, for example : https://en.wikipedia.org/wiki/Nuclear_isomer#Decay_processes Isomeric transition is made of two processes : $\gamma$ emission and internal ...
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Why does chart of radiative decay modes appear in two different conventions (x and y axis switched) for english and french versions in wikipedia?

Why does chart of radiative decay modes appear in two different conventions for english and french versions in wikipedia ? Which one is more academic ? On english version, the Z number is in x axis, ...
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Why irradiated color CMOS sensor shows white (not color) dots?

I exposed CMOS imaging sensor (OmniVision OV2710) to radiation from Radium watch dial, through 2 glass layers (test tube + IR-cut filter, so all low energy particles were filtered out). On the image ...
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$β^-$ decay should be impossible

I have gone through texts about Radioactivity.What I understood is that The Basic cause of radioactivity is dominant electrostatic repulsion over nuclear force of attraction between nucleons due to ...
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What is the physical basis behind the half life of nuclear decay?

I'm trying to understand the physical basis of decay half-life (understanding there may be different bases for different types of decay...) and I came across this article: https://www.lanl.gov/museum/...
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How long will a cube of Plutonium-238 keep my tea warm? [closed]

Plutonium-238 gives off heat, which reduces over time due to its half-life. Suppose I have a mug of tea in a room temperature environment, and instead of dropping in a sugar cube, I dropped in a ...
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How to convert the deposition of radionuclides on surface from the atmosphere ($Bq/m^2 d$) to precipitation ($Bq/L$) on surface?

These are results from CROM tool and you can check the SRS-19 book. or the concentration of these radionuclides in the atmosphere ($Bq/m^3$) to precipitation on water ($Bq/L$)? If I have a value of ...
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What is the extreme long-term elemental composition of the universe?

In Freeman Dyson's classic 1979 Time Without End paper he points out that, if proton decay does not occur, then normal matter will spontaneously fuse to iron on a timescale of $10^{1500}$ years, and ...
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Radioactive Dating: How do we know the initial amount of radioactive atoms present in the object?

I'm currently reading a book about Earth's geological history and the authors mentions radioactive dating as on of the methods used to estimate the age of given fossils. It obviously does makes sense ...
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How can integration be used in deriving radioactive decay formula?

I recently learnt the derivation of radioactive decay formula and I am quite surprised about using integration to derive the formula. But $N$ (the number of atoms) can only be discrete numbers (like ...
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The number of active nuclei left after a half life has passed

This is the given statement: A radioactive substance has a half life of 1 hour. Therefore if two nuclei of the substance are present initially, after 1 hour only one will remain undissociated. I ...
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Need help understanding a radioactive decay question

I have the following question: A stationary nucleus of uranium-$238$ undergoes alpha decay to form thorium-$234.$ The following data are available. Energy released in decay $4.27 MeV$, Binding ...
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Why is an alpha particle 'specifically' emitted in radioactive element and not other some other particle? [duplicate]

Why is an alpha particle emitted from any radioactive element if it is decaying? Why can it not emit multiple protons + neutrons one after the other or any other particle that is heavier than an ...
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How do neutrino masses change the shape of the $\beta$ decay spectrum?

It is more-or-less established that neutrinos have masses. But as of now, $\nu$-masses have not been directly measured in the laboratory. But I heard a talk where the speaker said that efforts are ...
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How should I treat background radiation in an experiment?

I am performing an experiment to verify the inverse-square law for the intensity of a beam of $\gamma$ rays emitted by a sample of $^{60}\text{Co}$. The set-up is as follows: A Geiger-Müller tube ...
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Why does the same proportion of a radioactive substance decay per time period? (half life)

Just wondering, if decay is random, why does the activity half every half life, as in, why does it have to reduce by the same proportion in the same time period?
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Is a planet hot inside because it is still hot from beginning, or continuously heated? [duplicate]

If a planet emerges from multiple colliding pieces, that causes its material heat up. Later, an existing planet is continuously heated by radioactive decay, tidal forces and other effects. But are ...
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Half life of radioactive elements: are there some atoms in a different state than others? [duplicate]

I think I generally understand what half-life means. What I wonder is, in a large collection of atoms of a radioactive element, are some atoms more likely to decay than others due to internal state or ...
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Fundamentally, why do some nuclei emit ionizing radiation?

I understand that some nuclei and their isotopes are not stable and therefore at random intervals bits of the nucleus (i.e. protons & neutrons) break away with differing amounts of energy ...
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What to think of the convergence of the logarithmic integral and its repercussions in QM?

Suppose we prepare a certain quantum system with Hilbert space ${\cal H}$, a self-adjoint Hamiltonian operator $H:{\cal H} \to {\cal H}$ whose spectrum is bounded below by $E_0\in \mathbb{R}$ (i.e. ...
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What is the relationship between single and double source gamma radiation?

I am a physics student currently undertaking a labs project about gamma radiation, we measured the spectra of different sources using a scintillation counter, my lab partner and I were wondering if ...

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