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Used nuclear fuel contains fission products like cesium-137 and iodine-131. When that escapes from the core of the reactor surfaces, clothes, food, dust etc will get "contaminated" with radioactive isotopes. People will ingest and inhale these. Unhealthy. But there is no infection. After a shower and clean clothes, such people are not a danger to others. ...


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Yes there is difference between binding energy of atom and nucleus. Rest mass energy of atom=rest mass energy of electron +rest mass energy of nucleus - Binding energy of the atom. Rest mass energy of nucleus =rest mass of proton +rest mass energy of neutrons - Binding energy of nucleus. Since both atom and nucleus are bounded system because of attraction ...


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I hope this article help which I got from the mentioned website. https://www.explainingthefuture.com/helium3.html Helium-3 is produced as a by-product of the maintenance of nuclear weapons, which could net a supply of around 15Kg a year. Helium-3 is, however, emitted by the Sun within its solar winds. Our atmosphere prevents any of this helium-3 arriving ...


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A star's ability to synthesize elements heavier than helium depends on its mass. A star of sufficient size will indeed burn hydrogen all the way to iron in its core- but this will not happen in Our Mister Sun.


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This is something that can be calculated knowing the composition of the spent fuel, the decay constant for each isotope, and the "radiotoxicity" of each isotope. A typical graph looks something like this: Note that both axis are log scales. In rough numbers, it takes about a million years before the radioactive waste is the same toxicity as the natural ...


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The question is: Has anyone ever considered and/or investigated a purely fusion type of explosive device? Oh yes, the so-far mythical pure-fusion bomb. For a pure-fusion reaction, let's consider the easiest case, D-T. This is basically what an h-bomb uses, with intermediate steps. The problem is the required (pressure * dwell time) to get enough ...


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On the LibreTexts website the page Isotope stability contains information relevant to the question. A nucleus is classified as stable when there is no known half-life On the page a diagram labeled 'Type of decay' is displayed. For each atomic number (the amount of protons) there is an optimum for the ratio of neutrons to protons. When the number of ...


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Bismuth-207 is suitable for calibration of beta detectors because it emits relatively many internal-conversion electrons with energies of 942 keV and of 1016 keV (from the K-shell and from the L-shell). Its beta continuum is at lower energies. http://przyrbwn.icm.edu.pl/APP/PDF/129/a129z6p08.pdf It also has a suitable halflife of about 30 years.


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Bismuth-207 is one of a large ensemble of radioisotopes used as "standards" for calibration of detectors. Some others are listed in, for example, this catalog. I don't see any indication that bismuth-207 is used any more frequently than other standards (the only detector calibration I've done has used cesium-137 and cobalt-60), but one possible advantage is ...


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One of the guiding principles of physics is that anything not forbidden is mandatory. If it's possible for something to happen, then somewhere in the universe it happens spontaneously. In particle physics, this means that if there's some particle that you can produce resonantly in some well-chosen reaction, that particle is a background contributor to ...


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Bosons tend to be force carriers - all of the currently-known bosons are force-mediating particles. So, it seems natural to infer that, if this new particle is a boson, it would imply the existence of a previously unrecognized force of nature.


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Rob's answer is giving the correct physics, but since you are a "smart middle schooler" I would like to address the rest of your question. To start with it will be good to increase your background on axions by reading the wikipedia article. , for encyclopedic information. Axions are the particles that let energy flash between a matter particle and its ...


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For a nucleus with medium mass, the first excited vibrational state is typically at an excitation energy of about 1 MeV. We can relate this to a frequency via $E=\hbar \omega$, which gives $\omega\sim10^{21}$ Hz. This is what is known as an isoscalar vibration, in which neutrons and protons move together. Vibrating molecules is not the same thing - which ...


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Here is a quote from https://www.accessscience.com/content/giant-nuclear-resonances/288700 : Elementary modes of oscillation of the whole nucleus, closely related to the normal modes of oscillation of coupled mechanical systems. Giant nuclear resonances occur systematically in most, if not all, nuclei, with oscillation energies typically in the range of 10–...


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The axion is a hypothetical particle; no axion has been observed. (Neither have any particle-antiparticle oscillations.) Since we don't know the quantum numbers of any axion, we don't know whether they are distinct from their antiparticles or not. I'm pretty sure that most models of the axion don't have any quantum numbers which would change sign under ...


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The figure in the Nature article is a calculated spectrum, I think, the sum of two distributions with the same area and different Q-values. Panel (d) in that same figure indicates that the range of the Sr-90 beta particles in solids is only 1.5 mm. My best guess is that your Sr-90 is embedded or covered by 1 mm or so of stuff and/or that your detector is ...


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Yes, a nuclear "shaped charge" is possible. You can think of a conventional shaped charge as a set of small explosive charges in a particular 3D arrangement(e.g., a conical shell). It is the arrangement of the charges and the relative timing with which they are triggered that determines the shape of the emerging shock front. An array of small nuclear ...


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Spins are angular momenta. Angular momentum is a vector, and conservation of angular momentum imposes the sign on the spin found. If in a reaction the electron goes off with a spin -1/2, the antineutrino-electron ( which conserves lepton number) has to have +1/2. The title though Why do antinutrinos have a spin of 1/2? is not concerned with the vector ...


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Binding Energy is considered negative because it's the energy needed to separate the constituent parts. Suppose you have a simple Hydrogen atom, just a proton and an electron. You need 13.6eV to separate the proton and electron an infinite distance away from each other. So the energy of the atom in the ground state is $m_pc^2+m_ec^2+BE$ where BE=-13.6 eV....


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The answer touches upon the concept of Big Bang Nucleosynthesis (BBN), which is excellently explained on a graduate level in Baumann's lecture notes. The key idea is the following: In order to form metals (anything heavier than hydrogen and helium), you need deuterium nuclei. But deuterium nuclei are only formed significantly when the temperature of the ...


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This is because of a principle known as lepton number conservation. "Leptons" are a class of elementary particles which includes both electrons and neutrinos (the only stable examples), as well as their associated anti-particles. The lepton number is the total count of leptons in a physical system, where that anti-leptons are counted as though they were a "...


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235U has a half-life of almost a billion years, so its decay rate is very low. This makes it relatively safe to be around. When it does decay, there is then a decay chain in which alphas, betas, and gammas are emitted. The alphas can't hurt you unless you're exposed internally. The betas are more penetrating but still usually not very harmful unless you're ...


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Hydrogen is the easiest element to get started "burning" into helium via nuclear fusion. Helium will "burn" too via fusion but is harder to "ignite". Each successive element as you go up in mass in the periodic table is capable of supporting fusion but as the mass goes up, the temperature needed to trigger fusion increases while at the same time the amount ...


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No nuclear reaction rates can be altered as far as we know, other than by the well-known method of hitting the nuclei with neutrons. Having said that, some people keep reporting correlations with solar activity, possibly related to some undetermined neutrino-based reactions some not so recent articles with links to papers on the subject: https://...


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Short answer: Yes, mostly, with some exceptions. Long answer: Nuclei can only be changed by nuclear processes. So the everyday chemical transformations that go on in our bodies and in the world around us do not affect the nuclei of the atoms involved. However, some nuclei are naturally unstable and will spontaneously decay or transform themselves into ...


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The fission fuel in an atomic bomb is always undergoing spontaneous fission and hence emitting neutrons, but at a very slow rate. The rate stays slow in an untriggered bomb because the neutrons being produced are allowed to escape before they can trigger more fissions within the bomb material. That bomb material is not pre-processed in any way to force it ...


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Neutrons are introduced when the bomb is detonated. The way it works is that (at least for a plutonium bomb), once the detonator is pressed, a very precisely machined and synchronized set of high explosives is set off around a plutonium core, which then compresses it to a density high enough to sustain the fission chain reaction (if the nuclei are too far ...


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In nuclear bombs, initiators are typically used to produce initial neutrons, the initiators can be activated by a shock wave caused by conventional explosives.


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I don't know the internals of either of those programs, so the following comments are rather general (and based on my own experience with more specialized event generators; including one written from scratch from first-principles and couple I've debugged and improved). The calculation of cross-sections generaly requires that you compute several things A ...


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At least in the field of radiation protection, spontaneous fission actually is considered as a decay mode. For example in ICRP, 2008. Nuclear Decay Data for Dosimetric Calculations. ICRP Publication 107. Ann. ICRP 38 (3).: Spontaneous fission Spontaneous fission is a decay mechanism resulting in splitting of the nucleus into lighter nuclei, referred ...


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Behind the scenes, it is the strong force. But on the nuclear scale, it looks quite different, and is mediated by pions (composed of two quarks) rather than gluons. Sometimes the resulting force is called the residual strong force.


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Is it not possible that incoming electron excite the hydrogen atom and then when it de-excites it releases radiation? Yes, that is what is happening. It is a confluence of photons, and it has frequencies that start from gamma rays and end in very low frequency ELF. The spectrum of the hydrogen atom emitted photons that create radiation is in the visible ...


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Radium that was used for luminous indicators was combined with a phosphor. The radiation excited the phosphor and that was what glowed (usually green). If you have enough radium in the dark, it can ionize the nitrogen in the air. As the nitrogen recombines with electrons, various emissions are possible, but in the visible band, blue is strong. You'll see ...


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Yes. In the case of nuclear states, the mass difference can be measured with remarkable precision by high resolution mass spectroscopy. I found this paper by Babcock et al (2018) about different isomers of some isotopes of indium. There is good agreement with the energy differences inferred from gamma spectroscopy.


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Yes, according to special relativity, if you excite any bound system, you increase its mass because of $E_0=mc²$. You can increase its mass by this mechanism until the two constituents are finally separate. If you have two particles, their rest energy and therefore their mass is always biggest in the free case and lower in any bound state. If two free ...


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Yes, we can convert uranium-238 to uranium-235, but the last step of the conversion is a very slow process, so it's not practical. The standard way to obtain U-235 is to separate it out from natural uranium, typically using uranium hexafluoride; see Enriched uranium for descriptions of the various techniques. Here are the steps to convert U-238 to U-235. ...


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