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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 exactly is delta-14C and why are there periodic plateaus in the delta-14C curve?

I downloaded the IntCal13, IntCal09, and IntCal04 datasets (parent site), and when I plotted the last 24k years was surprised to see a plateau or even reversal appear every ~5300 years. Apparently we ...
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Why is a delta resonance decay not a radioactive decay

A delta resonance decays as given in http://hyperphysics.phy-astr.gsu.edu/hbase/Particles/delta.html . I wonder, why is it not a radioactive decay? In principle, most/all decays should be radioactive ...
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Are human beings radioactive?

I am reading "The greatest story ever told - so far" by Lawrence Krauss. He starts chapter 9, Decay and Rubble, telling how he was shocked when he realized that humans are radioactive. When I first ...
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Possible to detect presence of nuclear bomb? [closed]

Take, for instance, a W-80 nuclear warhead. Does technology exist, say in the form of a satellite or drone, that could detect the warhead's presence (assuming it's not enclosed in some kind of ...
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How is Electron emitted in a Beta Decay? [closed]

In a beta decay , a neutron converts into proton and an electron. By How is one extra electron created? Are two electrons created by one neutron?
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penetration of Fe55 X-ray photons through glass

Can X-ray photons from Fe55 (one radioactive isotope of iron) pass through glass ?
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Gamma from U238 decay chain

Where can I find detailed information on the gamma background from the U238 decay chain? Edit: Thank you for your replies. I need to find all the branching ratios and extract information of all the ...
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1answer
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Why do half lives of Carbon isotopes vary by a great extent?

Both Carbon-14 and Carbon-15 decay by the $\beta^-$ mechanism but the half life for $C^{14}$ is approximately 5500 years whereas that if $C^{15}$ is around 2 seconds.What causes this disparity in ...
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Has there been any R&D(let alone progress) in the development of gamma voltaic cells?

I ask this because it is my understanding that gamma rays form ion tracks and oxygen radicals when gamma emitting material is immersed in an aqueous solution. Cesium-137 is a very strong gamma ray ...
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Gamma spectrometry

Suppose I have a sample containing only 137Cs. Now assume it shows 100 cps counts for 137Cs, 662keV energy. Now I added 60Co (1173, 1332 keV) source in the same sample. Compton scattering ...
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Questions regarding germanium detector

Why n+ contact in n type Ge is not several hundred microns? . Why we require both additional p or n type contact? in p type Ge, why we require additional p type junction also? crystal itself should ...
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How to derive the allowed beta decay selection rule $\Delta L=0$?

Starting from the beta decay matrix element and Fermi's golden rule how can one show that the matrix element at the leading order vanishes unless $\Delta L=0$?
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Talking Radon: Activity or Concentration

Currently I'm working on my PhD in environmental sciences and we are measuring Radon-222 in air using a commercially available detector. The results from the detector are given in units Becquerel per ...
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Is synchronized radiation possible?

Could it be possible to make 2 or more radioactive atoms, maybe plutonium, emit radiation at the same time? A kind of synchronized radiation. Perhaps this can be the basis for some kind of laser too.
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I have proved that radioactive disintegration is first order using probability. Is my proof correct? [closed]

I am a high school student and this is just a small attempt to prove why radioactive disintegration is first order. I don't even know if it has already been proved or not. Please let me know. I later ...
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Can't see any traces of particles in my Wilson chamber without radioactive material

I am doing an essay about particle physics and I need some help. I am comparing the results in a Wilsonchamber with and without a radioactive material present. I were able to see a lot of traces from ...
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Does the half-life of an element mean it will never decay completely?

Example: Half life of Polonium-194 is 0.7 seconds. If we supposedly take 50g of Polonium, there will surely be a time when no more of this Polonium will be left because if we consider the decay ...
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Theoretical explanation behind alpha particle emission [duplicate]

I have started studying radioactive decay. When I studied alpha-particle emission from an unstable nucleus I wondered why should there be emission of helium nucleus only(alpha particle) and why not ...
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1answer
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Nuclear reaction – What is the asterisk an indication of?

I've been observing the two-step decay of iodine-131 and can't quite determine what the asterisk above Xenon-131 indicates. I'm currently unsure as to what precisely the superscript asterisk on Xenon ...
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How to interpret the radioactivity for a radioactive material that generate isotopes?

I have a Strontium-90 radioactive source. The radioactivity of this source is $0.1\mu\ \rm Ci$. This source $\beta$−decays into Yttrium-90. Then Yttrium-90 $\beta$−decays into Zirconium-90 with a ...
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Why is Neon not used as a coolant for gas cooled nuclear reactors?

What is the reason that Neon is not considered as good coolant for gas cooled reactors? I haven't found any research nor experiment with Neon in this field. As I checked out Neon has small neutron ...
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1answer
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In a Radioisotope betavoltaic cell, does the amperage or voltage decay?

In a tritium-powered betavoltaic cell, the power output obviously decreases as the tritium decays. Is it the voltage, amperage, or both that would decay?
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Question relating to storage of radioactive substances

I saw this para while reading my physics textbook which said that radioactive substances were kept in thick lead containers with a very narrow opening. I understood the purpose of the lead but what is ...
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216 views

What is the mean life of a radioactive substance?

As far as my understanding goes, it is the average lifetime of a collection of nuclei undergoing disintegration. But doesn't each nucleus take an infinite amount of time to decay? Is that not why we ...
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Link between average lifespan and half time in radioactivity

I have learnt that in radioactivity $λ=\ln2/t_{1/2}$, thus showing the link between λ and radioactive half time. I have also learnt how to apply it in calculations (such as $R={R_0}e^{-λt}$) etc. Now ...
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How much do radiation-resistant suits cost?

Let's say you wanted a top-of-the-line, impenetrable suit to withstand high levels of radiation. How much does one of these suits cost?
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Unstable vs. stable nuclei plotted on a graph

The enclosed graph shows the number of Protons on the x-axis (Z), and the number of Neutrons on the y-axis for all elements (N). Stable combinations are marked by black squares, whereas unstable ones ...
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What happens to a radioactive material's atom when it disintegrates?

Suppose you initial had radioactive $2^n$ atoms (where $n$ is an integer). Now after a number of halflives the number of left out atoms becomes 1. Now what will happen to it will it disintegrate and ...
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Why do some gases transfer radioactivity and some don't?

I have recently read that helium is going to be used as coolant in Generation IV nuclear reactors, because Helium is radiologically inert (i.e., it does not easily participate in nuclear processes ...
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What's wrong with the following way to calculate mean lifetime from half-life?

So I understand that half-life $T_{1/2}$ is the time for the amount $N(0)$ to reduce by half. Basically, $$N(t)=N(0)2^{-t/T_{1/2}} $$ My question is that why can't I use this to directly pull out the ...
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What is the reason for radioactivity?

In any radioactive series we can observe that the half-lives of a daughter nucleus might be less than that of the parent nucleus. If the reason for radioactivity is gaining stability, why does a more ...
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Is this samarskite producing Xe-135?

I left a small sample of samarskite (a uranium bearing mineral) directly beside a radiation monitor for a few days as in the photo below. I then removed the samarskite, left the radiation monitor in ...
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Is there a way to slow down radioactive decay? (with mathematical proof)

See http://wtamu.edu/~cbaird/sq/2015/04/27/can-the-decay-half-life-of-a-radioactive-material-be-changed/ It stated that relativistic effect(obviously) and chemical component can slow down the radio ...
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Which elements or isotopes can be analyzed by Neutron activation analysis (NAA)?

Some sources name only a handful, but that might refer to the use of optical film. Others state more than 70. I would like to know which elemets or isotopes can be detectet/imaged by NAA.
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What effect does radioactive material have on the structure of spacetime? [closed]

I am curious as to how nuclear energy, from a nuclear blast could effect the structure of spacetime if the radiation escaped the atmosphere. Would it weaken the structure or would it be harmless?
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When to involve electron mass in energy calculation of beta decay

I would just like to apologise for the horrible images because I have no idea to format the subscripts of the elements. Why is that we do not have to account for the weight of the electron in beta ...
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Why alpha particles inestead of hydrogen or duetereum?

I know atoms undergoing alpha decay emit alpha particles, but I was wondering why specifically helium nuclei? If these atoms wanted to emit the smallest unit of matter (I'm talking about hadrons here, ...
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Should Copper 65 and Copper 63 isotopes have a larger density than a copper 29 atom?

I was looking at the first page of a paper (see https://aip.scitation.org/doi/10.1063/1.1735598#Metrics-content for details) and I ran across something odd. According to the paper, Copper isotopes 63 ...
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1answer
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Integrating $1/x$ in radioactive decay derivation

I have a question concerning, for example, the derivation of the equation for radioactive decay. You start with the following differential equation $$-\lambda \cdot N=\frac{\mathrm dN}{\mathrm dt}$$ ...
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Where does energy come from in fusion/fission?

Hello! I am trying to understand where does the energy come from in fusion and fission reactions. Looking at the table, the more stable atoms are the ones with the highest binding energy- the atoms ...
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In $\beta^{+}$ decay the produced positron annihilates with an atomic electron?

The Q value of $\beta^{+}$ decay with atomic masses $m$ is : $${\displaystyle Q=\left[m\left({ {^{\mathit {A}}_{\mathit {Z}}X}}\right)-m\left({{^{\mathit {A}}_{{\mathit {Z}}-1}X'}}\right)-2m_{e}\...
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What is the relationship between the amount of radioactive substance and the harm it does to the body?

This is probably a very simple question, but I wonder how the amount of radioactive substance is related to the radiation it emits and therefore the harm it does to the body. If I held 0.1g of barium-...
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If a nucleus is radioactive, will another nucleus with lesser binding energy be necessarily radioactive?

Consider two nuclei A and B. Let the binding energy of A is less than the binding energy of B (i.e., A is unstable compared to B) and B is known to be radioactive. Does it mean that A also has to be ...
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Are there radioactive elements that can be seen to diminish/change with the naked eye?

That is, after creating a quantity of a radioactive isotope with a half-life of several seconds or minutes, could the sample be seen to change into decay products with the naked eye? (Excluding ...
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Half-Life of Radioactive Isotopes [duplicate]

Why do radioactive isotopes have a half-life? I know that they decay in order to become stable but why would it take out enough subatomic particles to be half? Or am I approaching this question the ...
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1answer
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Radioactive pollution [closed]

Why doesn't anyone somehow collect radioactive elements from polluted areas like Pripyat in Chernobyl? Should we really wait for thousands years until it stop being radioactive? Maybe there are ways ...
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1answer
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Is the arrangement of nucleons within a nucleus identical between heavy elements of the same type?

In elements with smaller atomic numbers, we will typically see graphic renderings of the nuclear structure with the protons and neutrons displaying some sort of symmetry spread within the nucleus. ...
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Creating isotopes by shooting neutrons into an unstable nucleus [closed]

I've been doing a lot of amateur research lately (youtube videos) on particle physics and find it all really interesting. I'm also a crazy alien conspiracy theorist who believes in the whole "Bob ...
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185 views

Equation related to the radioactive decay being random

How is time decay randomness calculated? it's similar that on variables like position? If we describe a system with $\phi\left(x,t\right)$ as wave function, $\left|\phi\left(x,t\right)\right|^2$ as ...
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Can radioactive decay particles be modeled as plasma?

Since plasma is simply ionized gas (ie. charged particles), with the exception of neutron ejection (no charge) and gamma radiation (photons), can the natural decays of an isotope be modeled as plasma? ...