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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What really causes radioactivity?

We know that a nucleus can transform itself by many ways such as fission, alpha decay, beta decay, etc. But what is it that propels this to happen? Is it just the instability of the nucleus in general?...
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How does positron emission happen naturally? [duplicate]

How does positron-emission happen naturally, for example in Potassium-40? Isn't the added mass of the neutron and the position more than the mass of a proton? Where does the proton get this extra ...
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Calculate the C14 decay rate of a living organism [closed]

Calculate the decay rate of a living organism which has 2g of carbon. The ratio of C14 to C12 is $1.3 \times 10^{-12}$. The half life of C14 is 5730 years. I tried solving this problem with the ...
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How can I find a theoretical maximum amount of radioactively polluted water which could be created by a single nuclear reactor?

This question has a lot of tolerance. The current context is that I'm writing a story which involves a group of terrorists who are using the threat of radioactive water pollution to deter ...
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27 views

Does decay rate change with time?

In a fire alarm, if we start with americium-241 which emits radiation at 370 kBq (as an example) what will have happened to the decay rate after 470 years (half life is 470 years). The amount of ...
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Is there a mathematical model for predicting when gamma rays are produced in radioactive decay?

My understanding of gamma ray emission from radioactivity is that the daughter particle is in an excited state, which then produces a gamma ray as the electron drops energy levels. In the case of ...
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When are W-bosons emitted?

According to this Wikipedia page W-bosons are involved in beta decay. According to Wikipedia, this occurs when a down quark turns into an up quark and also emits a W− boson. When this happens in a ...
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Is there any non-experimental way to determine what substances are radioactive? [duplicate]

Is there any way to determine if a substance is radioactive and if so, is there any way to determine in what form the radiation will appear, like β- or α-radiation? For example, if I am making a decay ...
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Is there any full Compton scattering experiment done with x-ray since 1923?

The original paper of A.H.Compton 1923 did not provide data of a full experiment; he provided 3 points. Was his result corroborated by others? Can someone provide a real full set of data for Compton ...
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68 views

How are energies determined in gamma ray calibration standards?

In operating scintillation gamma ray detectors, certain gamma ray standards are used for calibration: Energy (KeV) Na-22, 511 Mn-54, 835 Co-57, 122 How are ...
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Why are all isotopes of tungsten considered (theoretically) unstable?

The Wkipedia article on tungsten says: Naturally occurring tungsten consists of four stable isotopes ($^{182}\mathrm W$, $^{183}\mathrm W$, $^{184}\mathrm W$, and $^{186}\mathrm W$) and one very ...
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Equivalences for mCi doses and cGy?

I was searching a lot and could only find dosages for curing cancer and allowed emission, but no Iridium 192 dose that could be given internally through brachy sources been found, lets say a 700 cGy ...
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Positron beta decay in stellar core plasma

According to introduction level textbooks $\beta^+$ decay, that is conversion of protons into neutrons only occurs in atomic nuclei. $$p \xrightarrow{\beta^+} n + e^+ + \nu_e$$ I understand that it ...
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Would alpha decay taste sour?

If someone were foolish and/or brave enough to build a device to focus the alpha decay products from a radioactive sample, then point it at their tongue through their open mouth, would it taste sour, ...
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Origin of Ba-133 contamination

On a stainless steel part that was removed from a spent fuel pool of a pressurized water reactor, we found (among the usual contamination with activated corrosion products, fission products, and ...
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Solved problem on radioactive decay

I encountered a question that was given the disintegration rate of a radio active source measured at the interval of four minute. The source is consisted of two types of radio nucleus and the half ...
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High-purity silicon detector vs HPGe for gamma-spectroscopy

Is it possible to construct a high-purity silicon detector for gamma spectroscopy the same way HPGe detectors are made? Will it work when cooled to the same 77 K? Why HPGe is mainly used for gamma ...
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Do radioactive materials have a property for their natural heat output?

Consider room temperature, would a fissile/fissionable element be naturally warmer to the touch (or a sensitive thermometer) compared to say a glass of water (because the atoms have more ongoing ...
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How do we know the rate of decay for radiometric dating is constant?

http://www.purdue.edu/newsroom/research/2010/100830FischbachJenkinsDec.html The link above talks about a paper by Sturrock et al. in which slight fluctuations were detected in radioactive isotope ...
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How to transform activity ratio to isotope ratio? [closed]

I am given a table that describes an ancient spillage of spent nuclear fuel: ...
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41 views

Can beta rays induce radioactivity

I am aware that alpha particle can induce radioactivity. Is it also true for beta and gamma rays?
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Why do the elements Tc and Pm have such low abundances?

What specific nuclear and electronic properties make these two elements (Tc & Pm) almost disappear from solar and galactic abundance tables?
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Why does cluster decay almost always emit an even number of both protons and neutrons?

Looking on Wikipedia's cluster decay article, I see that almost all clusters emitted from a nucleus have an even number of both protons and neutrons (not necessarily the same number of each). The only ...
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Why does ionizing radiation hamper radio communication?

After having finished the second episode of the HBO Chernobyl series, wherein a helicopter flying too close to the core loses radio communication with the ground and is unreachable, I started thinking ...
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Can quantum theory predict the radioactive properties of given element?

I think there is no known physical theory that predicts the radioactive properties of elements in the periodic table. I guess it would be great if we can predict theoretically the radioactive ...
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Trinity vs Nagasaki

From what I read the radiation levels in Nagasaki today are equivalent to the natural background radiation levels in the surrounding areas. On the other hand, the radiation levels at the Trinity test ...
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162 views

Polonium 210 degradation

From what I read online - Polonium 210 is the isotope used as the neutron initiator in nuclear weapons. But the half-life of this element 138 days. This raises questions: how do substantial ...
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Why does gamma radiation have a low ionising ability?

It is commonly taught that alpha particles have high ionising ability and low penetrating ability (explained by saying due to their large charge and kinetic energy, they are able to knock off ...
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Irradiated persons as sources of radiation?

The new HBO series "Chernobyl" is supposedly filled with misconceptions about radioactivity, among other things, according to an opinion piece published in "Forbes". In particular: "The most ...
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Order of magnitude radiation measures conversion?

Standard unit of ionizing radiation dose is Sievert. I can get a rough idea of how dangerous absorbing various amounts is from https://xkcd.com/radiation/ and other sources. There are many other ...
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Why is the graphite moderator in a nuclear reactor radioactive?

Some nuclear reactors (like the RBMK in Chernobyl) use graphite as a neutron moderator. As far as I understand, this graphite material, either in rods or as blocks with embedded channels, surrounds ...
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How can corium eating its way into water tanks cause a megaton scale explosion? [duplicate]

The 2019 miniseries "Chernobyl" appears to state that the "lava like" substance of melted radioactive matter from the core, the so-called "corium", could eat its way down into the water reservoirs ...
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How does an ordinary object become radioactive?

In the 2019 miniseries "Chernobyl", ordinary objects are depicted as being capable of becoming radioactive, such as clothes, water, stones. How exactly does something composed of a non-radioactive ...
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Why are lighter nuclei dominated by $\beta$-decay and heavier ones by $\alpha$-decay?

While I'm trying to understand the nature of radioactive decay, I found that the lighter nuclei mostly have $\beta$-decay while heavier nuclei have $\alpha$-decay. From what I know is that the $\...
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What is wrong with my Cloud Chamber? I can't see supersaturated vapor or particles [duplicate]

I'm using black felt at the bottom, a small tin can, and black sponge around the inside of the can. I hot glued them onto the can, and then put 91% isopropyl alcohol in it. Afterwards, I used some ...
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How does the Earth's center produce heat?

In my understanding, the center of the Earth is hot because of the weight of the its own matter being crushed in on itself because of gravity. We can use water to collect this heat from the Earth and ...
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96 views

Why is the isotope of lead-206 stable against alpha decay?

The mass of Lead-206 is larger than that of Mercury-202 + Helium-4. Why is then Lead-206 stable against alpha decay? I have heard that the beta-decay can stabilize a nucleus against alpha decay, and ...
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617 views

Probability of decay of a nucleus

Question: A given sample of radium-226 has a half life of 4 days. What is the probability that a nucleus disintegrates after 2 half lives? Attempt at solution: After time $t$, the number of ...
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Confusion in Positron Decay

As we know, in a positron decay, by the involvement of weak forces, a proton converts into an neutron, emitting a neutrino and a positron, all of this happens inside the nucleus. Why doesn't the ...
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Why do unstable nuclei form?

Why do unstable nuclei form? Is it that we simply find unstable nuclei in nature and understand what these nuclei do in order to become more stable? I feel like textbooks gloss over this question ...
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Speed of beta-decay ejected electrons

It is well known that the energy spectrum of the beta-decay electron is continuous; it was confirmed by the Ellis and Wooster 1927 experiment. It means the electron are ejected with speeds that may ...
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is the half-life of a radioactive isotope dependent on the type of radiation it releases (alpha/beta/gamma)?

I understand the term half-life but I am not sure if the type of radiation it emits is a factor affecting an isotopes half-life
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Limit to number of neutrons in nucleus [duplicate]

As far as I understand the number of protons in a nucleus is limited because Coulomb forces grow faster with the number of protons than the nuclear force. So alpha/cluster decay limits the size in ...
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Nuclear Propulsion

I am watching a video on nuclear rocket engines, specifically the Nerva engine. It has a propulsion efficiency of 750-800 Isp versus chemical rockets which are only 350-400 Isp. The follow on NRX ...
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Tritium decay energy too small for quark model

So $^3$H turns into $^3$He through $\beta^-$ decay, right? The energy of this reaction is only 18.6 keV. However, according to the constituent quarks model, the only thing different between $^3$H ...
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Why is energy released during fission reactions?

If the energy released during a fission reaction is the binding energy then what energy is left to bind the nucleons together? I'm very confused if there's a better explanation on fission I'd ...
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What exactly is binding energy?

I've been reading on radioactivity but along the way I got confused, if binding energy is the amount of energy used in holding the nucleus together then why is binding energy also the amount of energy ...
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Half thickness of lead using a Ba-133m source, references?

I carried out an experiment to calculate the half thickness (half value layer) of lead. The experiment was done using what i believe to be a Ba-133m source on this software: https://radiation-lab....
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Why does a single X-ray photon generate 1620 electrons when it hits CCD detector?

Fe55 is one radioactive isotope. It emits X ray photons : mainly k-alpha & k-beta lines. Why does a single X-ray photon generate 1620 electrons when it hits CCD detector ? While, in photo-...