Questions tagged [nuclear-physics]

Nuclear physics is the study of the composition, behavior and interaction of atomic nuclei and their constituent parts.

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Can nuclear material be detonated with light?

In this question https://space.stackexchange.com/questions/65842/nuclear-solar-reflective-plasma-drive I propose a question to use the light from the sun to start a nuclear chain reaction to propel a ...
Justintimeforfun's user avatar
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Is the sun multinucleated or is there just one point at or near the center of the sun where fusion is occurring?

I was just reflecting upon my thinking and probably any illustration in books or movies: I assumed a single general area near the "geographical" center where the actual fusion occurs. But ...
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Threshold energy formula

In Krane's Introductory Nuclear Physics, in chapter 11, he uses the conservation of energy and momentum to derive the formula for the threshold energy of a reaction a + X → b + Y (with X being an ...
Pedro Nogueira's user avatar
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Effects of a hypothetical "proton-decay bomb" for a fictional story [closed]

I'm writing a science fiction story in which I need a devastating weapon of mass destruction that is far worse than nuclear bombs. For some reason, I'm fascinated by the idea of a "proton-decay ...
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The reaction of hydrogen and neutrons [duplicate]

If there is no excited state in the deuterium nucleus, how does the reaction occur when hydrogen and neutrons collide to emit gamma rays and become deuterium?
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Hydrogen and deuterium reaction with neutrons

In my book "Introduction to nuclear engineering" by John R.Lamarsh and Anthony J.Baratta, (4th edition), they explain "The nuclei 1H and 2H, which are present in large amounts in many ...
SungJin Park's user avatar
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Are the relativistic masses conserved in nuclear fission? [duplicate]

If A $\rightarrow$ B+C+ΔE, then $M_{B}+M_{C}< M_{A}$ So, whether the masses involved were the relativistic or the rest, they aren't conserved. So, why would anyone say the rest masses, not the ...
Jack's user avatar
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Dependence of stability of nucleus on the packing fraction

How does the packing fraction of a nucleus affect the stability of the nucleus? A true and false based statement question came in a exam I gave, and it stated the statement "The stability of a ...
Shivansh Jaiswal's user avatar
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Why is the Ar-40 nucleus lighter than Ca-40?

I'm doing some problems on decay of K-40 with some students, and I'm baffled by the numbers I'm finding. I expected there to be a much greater mass defect for beta-minus decay than for beta-plus, and ...
Daniel Wicklund's user avatar
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Why does critical mass for radioactive isotopes seem to have little relation to half-life?

I understand that too short a half-life and flash point, becomes kind of meaningless, if the element generates too much heat, so this only applies to longer half-lives. Also, as I understand it, flash ...
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Decay constant Question in A level AQA physics

Mark scheme I don't understand 2.7. I have attatched the relevant part of the question and markscheme and also the links to full versions below. Apparantely you use the decay constant in 2.5 to find ...
ayron 13's user avatar
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How to think of the unit $\rm eV$?

How to get a sense of $\rm eV$? I mean when I know how much a metre is or a second is, but how to "visualize" when it is said atomic reactions are in order of $\rm eV$ and nuclear reactions ...
Questioningmind's user avatar
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Physical meaning of the multipolarity of gamma radiation

During my nuclear physics class, we talked about the multipolarity of gamma radiations but without going too much into the details, and I was wondering about the meaning of that, how can the radiation ...
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What is known about the isotope distribution of neutronium decay?

Sometimes it is known to happen. For example, neutron star mergers might result in unstable neutronium droplets which lose the enormous pressure that makes them stable. A "nucleon" of $10^{...
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Size of an atom

This may be a naive question, but today, while reading about the Rutherford experiment in my high school chemistry textbook, I came across the following sentence: "Calculations by Rutherford ...
tensorman666's user avatar
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Can the protium nucleus be in an excited state?

An electron in protium can absorb a photon and jump to an orbit of higher energy. Is an analogous procedure possible for the nucleus of protium (a single proton)? Can this nucleus be in an excited ...
azerbajdzan's user avatar
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Long and short range correlations in nuclear physics

In the introduction of chapter 6 of Ring and Schuck's book "The nuclear many-body problem" it is stated that "the Hartree-Fock method partially takes into account the particle-hole part ...
OutrageousKangaroo's user avatar
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Radioactive Decay Chain for the special case of equal decay constants (parent-daughter)

I have been trying to obtain an analytic solution for a daughter radionuclide's activity (or just the number of daughter atoms), as a function of $t\geq0$, resulting from the decay of a parent ...
Username134's user avatar
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Possible electron capture decay of $^{148}\mathrm{Gd}$?

While the nuclide $^{148}\mathrm{Gd}$ is only known to undergo $\alpha$ decay, with a half-life of $86.9$ years, I noticed that it has higher energy than its isobar $^{148}\mathrm{Eu}$: $m_{^{148}\...
Jianing Song's user avatar
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Binding energy of Hydrogen = 0 = 13.6 ${\rm eV}$? [closed]

I was solving nuclear physics today.I used the binding energy formula on hydrogen.I found that B=0.But,B is also,as mentioned in my textbook,13.6eV. How?
CODE_FOR_PURSUIT's user avatar
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How does pion exchange cause protons and neutrons to be attracted to each other? [duplicate]

I read that neutron and protons are attracted through exchanging pions between each other. However, as far as I understand, they are just exchanging a meson, not any force carriers. What causes them ...
thingthingthing123's user avatar
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Electrons and atoms

Electrons do not follow fixed orbits around an atom's nucleus but exist within "clouds of probability" (orbitals), where there is a high chance of finding them. As one extends the search for ...
Marco Fabbri's user avatar
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Cobalt atomic mass less than 100 % isotope mass? [closed]

Why is cobalt's atomic mass listed on periodic tables as less than 59 amu when its main isotope (virtually 100 %) is cobalt 59 with a trace of cobalt 60? After reading a bit I'm wondering if it has to ...
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Is there proof for: "Elements heavier than iron will decay to iron by processes such as fission and alpha emission"?

Freeman J. Dyson in his "Time without end: Physics and biology in an open universe", Lecture 2: Physics, part G: All matter decays to iron, claimed that on a long enough time scale "...
Sourabh Choudhary's user avatar
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Why does saturation occur when the populations of the spin-up and spin-down energy levels are equal?

I'm learning about NMR spectroscopy and I don't understand why saturation occurs when the populations of the higher and lower energy levels of spin are equal. Why wouldn't energy continue to be ...
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Asimov's nuclear intensifiers

Well, it is fiction: in Isaac Asimov's stories there are "nuclear amplifiers" that magically (fiction without even an attempt of explanation) produce a beam of W-bosons, thus amplifying the (...
Gyro Gearloose's user avatar
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Estimate values of $g$-factor

I'm not sure I understand how to compute the gyromagnetic ratios. Here's what figured out: if we consider an orbiting charged point-like massive particle we can $\textit{classically}$ compute the ...
polology's user avatar
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Maximum number of partial waves and matching point

I have read that a large number of partial waves, around 200, are required in a situation such as ${}^{16}$O incident on ${}^{152}$Sm at c.m. 65 MeV in Coulomb excitation Anybody familiar with ...
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$Q$-value (nuclear)

I'm studying principles of physics. I have a question. In my book, they seem to have calculated the Q value in different ways. $$ \begin{align} \rm p + {^{27}_{13}Al} &\rightarrow \rm{^{27}_{14}Si}...
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What is the definition of the 0th element of the spin 1/2 four vector?

Is it: $$ S_\mu = (I, \frac{1}{2}\vec{\sigma})\quad\text{or}\quad S_\mu = (0, \frac{1}{2}\vec{\sigma}) $$ Specifically in the "CHIRAL DYNAMICS IN NUCLEONS AND NUCLEI" Bernard,Kaiser,Meißner, ...
Alex Long's user avatar
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Is there an equation that can predict black hole formation from neutron star formation from supernova occurrence?

If supernovas can be predicted depending on the mass of the a star, (If its more than about 8 times the mass of sun it will eventually go supernova - https://www.space.com/23756-white-dwarf-stars.html)...
Sam Jones's user avatar
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How was Rutherford's model of an atom wrong?

They mention that Rutherford's model of an atom was wrong as in a circular orbit the electron would accelerate and hence radiate energy along with electric and magnetic fields. But why does the ...
Unknxwn's user avatar
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If we use Negative Ions as probe for nuclear reactions, will they get deflected?

I am studying the basics of Nuclear Physics, and just read about the Rutherford experiment. My question is if we use Negative Ions as probe for nuclear reactions, will they get deflected? If yes then ...
user393509's user avatar
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Derivation of mean life of a radioactive nucleus

How can the mean life of a radioactive nucleus be derived? Consider R.dt number of nuclei decaying in the time interval t and t+dt. Then, isn't the lifetime of those R.dt number of nuclei is t? But, I ...
Vinay5101's user avatar
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Does antimatter have the same half-life as ordinary matter?

Antimatter is just ordinary matter but with opposite electric charge. Scientists have created only a handful of antihelium-4 in the LHC. I am wondering if the half-life of, say, antiRadium-226 is ...
user6760's user avatar
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Why doesn't the water in a Light Water Reactor split to $\rm H_2$ and $\rm O_2$?

Intuitively I'd expect a nuclear reactor to produce gamma and neutron radiation powerful enough to knock hydrogen atoms/nuclei (or electrons) off $\rm H_2O$ molecules, some of which could recombine ...
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What is "point of interest" and why isn't there a Zref for determining electron beam quality with TRS 398?

What is "point of interest" and why isn't there a Zref for determining electron beam quality with TRS 398? ((To what depth do you put the ion chamber when you do high energetic electron ...
medical physics's user avatar
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When K-shell X-ray is emitted, how the vacancy in the L-shell are filled?

When there is a vacancy in the K-shell because of electron capture or incoming energy, an electron in the higher energy level will fill the vacancy and emit a characteristic X-ray. However, I think ...
siron's user avatar
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Why does this term of two electron masses appear when calculating the heat of these nuclear decay modes?

Consider the following two nuclear decay modes: $$^{64}_{29}\mathrm{Cu} \to e^- + \bar{\nu}_e + ^{64}_{30}\mathrm{Zn} $$ $$^{64}_{29}\mathrm{Cu} \to e^+ + \nu_e + ^{64}_{28}\mathrm{Ni}$$ The solutions ...
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Why is helium-4 the only nuclide with a negative nucleon binding energy?

He-4 is very unusual as it’s the only nuclide that does not accept another nucleon. In other words, even if you force a proton or a neutron into He-4, it will be kicked out immediately. If you ...
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What is the causation of the mass deficit in atomic nuclei?

I've always heard that when protons and neutrons are combined together into nuclei, the mass of the product is less than the mass of the constituents. And that this mass is called the mass deficit and ...
Wander verse's user avatar
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Most stable isobar for even-$A$ nuclei

In the Liquid Drop Model of the nucleus, the most stable isobar is the one whose atomic number $Z_{A}$ is the one corresponding to the minimum mass, and can be found from the mass parabola or, by ...
Momo's user avatar
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if decay rates were somehow increased, would neutron flux proportionally increase in a reactor?

I've heard people argue that decay rates in the past could have been faster. Despite not having a mechanism for this, I am curious about it. The oklo reactor is commonly cited as proof that decay ...
Hurdlegreen2's user avatar
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Two nucleons system with total isospin quantum number $T = 1$

I am confused with the resolution of this question: A system of two nucleons is in a state with a total isospin quantum number $T = 1$. What are the possible values for the total spin quantum number $...
japf's user avatar
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Why do nucleons pair up?

I'm learning about the semi-empirical mass formula currently, and in the explanation for the pairing term, the course notes say that it's energetically favorable for nucleons to pair up. Could someone ...
user374355's user avatar
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Beta decay of 6-Helium

In this reaction: $$\require{mhchem} \ce{^6_2He ->{^6_3Li}}$$ in the initial state there are two neutrons in the $1p_{3/2}$ that coupled (for the Pauli's principle) with antiparallel spin, so $J_i=...
Riccardo Benettin's user avatar
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High-energy neutron multiplier

Are there any materials that can function as efficient high-energy neutron multipliers? I have read about the utilization of Beryllium and Lead as neutron multipliers, but they seem to only be ...
S.T. Zweig's user avatar
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What forces are responsible for the conservation of momentum at the subatomic scale?

When I throw a ball at a wall and it bounces off of it and there is conservation of momentum we can say that the springiness of the ball and the wall is the action reaction force responsible for the ...
Alfred's user avatar
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What is the balanced nuclear fusion equation?

Given that the deuterium-tritium (DT) reaction has been identified as the most efficient for fusion devices, what is the ultimate balanced nuclear fusion equation?
nuclearninja's user avatar
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Parity of Photons

In nuclear physics, while studying gamma decay (Nuclear physics, Roy and Nigam, 1st ed, pp 450) I have read that the parity of photons depends on the type of multipole radiation they represent. Means ...
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