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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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Derivation for angle of diffraction of electron beam fired at thin metal sample (diffraction by nuclei) [duplicate]

My textbook says sinx = 0.61λ/R where R is radius. How do I derive this? Tried to search online and most sites just state what happens, not why it happens. I understand the Bragg equation is given ...
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Is a nucleus a collection of quarks or a collection of neutrons and protons? [duplicate]

I do not much about particle physics. But people say that neutron and proton are composed of quarks, and in turn a nucleus is composed of neutrons and protons. Therefore, the question is, is this ...
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Omnes function in particle physics [on hold]

Here's the paper of R.Omnes Please tell me how to get(2.3a)and(2.3b)from(2.2)
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Why are protons and neutrons the “right” degrees of freedom of nuclei?

This question may sound stupid but why do we visualize nuclei as composed of a bunch of neutrons and protons? Wouldn't the nucleons be too close together to be viewed as different particles? Isn't the ...
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What is more massive, Proton, standard Hydrogen?

If you consider the classical states of hydrogen, one in which the electron is rotating at an orbital distance of $r$ and then take $\lim_{r\to\infty}$ one obtains that the $r_\infty$ state has more ...
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How to determine the approximate order of the strength of nuclear force from Heisenberg's Uncertainty Principle

Today I came across a question , where I was asked to find the Strength of nuclear force from Heisenberg's Uncertainty Principle... Please can anyone help me out... I have come across a solution ...
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Infinite Subcritical Reactor with a plane Source; Deriving analytical solution with boundary conditions [migrated]

this might aswell be a mathematics question since I am only looking for a way to solve a basic model of the neutrondistribution in an infinite plane subcritical reactor. So the model for the ...
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Quantum Nuclear Corrections

I am interested in calculating quantum nuclear corrections to energy profiles or free energy profiles. For example, say I perform a DFT simulation for some molecules, and I the energetic profile in ...
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1answer
79 views

Is this reaction even allowed? [closed]

$$p+p\rightarrow p+n+\pi^+$$ According to coservation laws, is this Allowed or Forbidden? If Allowed what type of interaction is this :- Strong, EM. or Weak? Why? From conservation of Charge &...
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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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18 views

Errors of counts/count rates and LN(Count rate) [duplicate]

Just wanted to confirm something, I am doing a report on an experiment I did using a Geiger tube/counter. As radioactive activity is random, errors should be: Standard Error in count: √counts Count ...
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Nuclear Fusion Proton-Proton Chain

When hydrogen nuclei are able to overcome the coulomb forces, two protons collide. As a result, one of them decays into a neutron and a positron and electron neutrino are emitted. However, isn't mass ...
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Binding Energy and Energy Mass Equivalence

Consider a neutral atom. An external force acts on one of its valence electron so that it brings this valence electron to infinity away from the rest of the atom. The electron's kinetic energy does ...
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How much would the lifetime of the sun change if the reactions inside ended at 3-Helium

This is assuming no other changes. I am aware the PPI branch makes up 87.1% of the reactions in the sun, and that the PP sequence as a whole powers the sun, but I am not able to tell the amount of ...
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Why the nuclear fusion 6Li+D and 7Li+P reactions happens 10 time less than H+11B?

The first two reactions generates 2 alphas and the boron one generates 3, but boron has 2 more protons than lithium so should repels more to hydrogen. I suppose is a question of nuclear states, but ...
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Hamiltonian for a magnetic field

An atom has an electromagnetic moment, $\mu = -g\mu_B S$ where S is the electronic spin operator ($S=S_x,S_y.S_z$) and $S_i$ are the Pauli matrices, given below. The atom has a spin $\frac{1}{2}$ ...
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Estimating standard deviation of radioactive decay [closed]

I recently did a laboratory exercise where we had an amount of silver containing two isotopes. Silver with 108 and 110 neutrons, respectively. Using sensors and software, we measured the amount of ...
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1answer
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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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How to determine isospin $T$ (not just $T_z$) of a nuclear ground state

I’m trying to work out the total isospin and the $z$-component of the isospin for specific elements like $^{20}O$ and $^{20}F$ in the ground state. I’ve worked out the $z$-component, as I concluded ...
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3answers
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Why does it take so much energy to keep the protons and neutrons in an atom together

I heard on the net that the reason there is so much more energy released during the breakage of an atom, i.e. the sun, than from breaking a chemical bond is because the particles are pushing away so ...
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How is visible light not observed when slow moving electrons pass through water

Why do the electromagnetic waves that come from electrons moving faster than the speed of light in a medium create visible light but the EM waves that are produced by slower electrons produce no ...
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1answer
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Description of particles using co-moving frame in accelerator

I am learning particle accelerators and there is a basic concept as to description of particle beams in accelerators which confused me a lot. Moving orthogonal, right-handed coordinate system (x, y, ...
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2answers
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How does the exchange of pions result in the strong force?

I understand that the residual strong force is a result of an exchange of pions. But I fail to understand how this exchange results in a force that holds nuclei together! May this query please be ...
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Photodissociation as the triggering mechanism for star collapse

It is known (one can find this in every book about stars, for example Shapiro's, Tayler's and others) that photodissociation is the mechanism by which the collapse of a star which has burnt all the ...
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1answer
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Form of energy release

I know that fusion and fission can be esothermic processes if they happen between the "right" elements (meaning, indicatively, lighter/heavier than iron respectively). I always thought I got this ...
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Proportionality of rate of decay with the amount of nuclei present in the substance

Why is the rate of decay of a substance directly proportional to the amount of nuclei present in the substance? I don't know much about this topic, my teacher introduced us to this concept in class ...
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Magnetic force between ions

In the force between nucleous knowing the magnetic moment: $$F={\frac {3\mu _{0}}{4\pi |{\mathbf {r} }|^{4}}}(({\hat {\mathbf {r} }}\times {\mathbf {m} }_{1})\times {\mathbf {m} }_{2}+({\hat {\mathbf {...
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1answer
59 views

Introduction to nuclear physics

I want to self-study nuclear physics in order to understand nuclear reactors and nuclear weapons, what books can you recommend?
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2answers
84 views

Heisenberg's uncertainty in nuclear physics

I'm doing a course in Nuclear Physics but I think it focuses more on the experimental side so not everything is that rigorous. In the notes, lecturer gives an argument for why we should use electrons ...
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1answer
49 views

Does the nucleus have less inertial mass than sum of inertial masses of constitute protons and neutrons?

In nuclear fusion part of nucleons' rest mass goes into radiation energy. Does it mean that inertial mass of result nucleus decreased?
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1answer
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Is there any theoretical calculation for the nuclear magnetic moment for beryllium-7?

Magnetic moment measured for Be7 is -1,39. Is there a theoretical calculation which aproaches to this experimental value? I did not find any in the internet.
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How to calculate angular momentum given angular distribution

I have recently attended a colloquium on transfer reactions. At one point, the speaker was talking about calculating the angular momentum of a nuclear transfer reaction from an angular distribution ...
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3answers
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Why would gamma spectroscopy be a tool for nuclei?

I am very much familiar with Atomic spectroscopy, not much with nuclear spectroscopy. In atoms (electronic cloud), we have electromagnetic interaction that plays the leading role, whose exchange ...
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1answer
32 views

What is the Significance of Mass Excess?

I know that, what is Mass Excess according to the formula, but please tell me that why it is used. And as according to the formula, we take difference of Mass of atom and atomic mass unit times the ...
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2answers
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Using $E=mc²$ to simplify particle KE calculations?

In an old examination paper I found a question asking for the ratio between the KE of a nucleus and the KE of an alpha particle emitted from the nucleus. For reference here is the question and answer ...
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How fast do nuclei need to be traveling when colliding for them to break apart? [closed]

I don't mean fission or fusion reactions with uranium or such. I mean gold or lead or even hydrogen collisions, such as in these particle colliders or outer space, wherein the nuclei seem to touch, ...
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37 views

Binding energy of the nucleus

In a reaction U235+1n->141 Ba +92Kr +(3) 1n+200MeV, the energy released (200Mev) is of one atom or of 6.023*10^23 atoms?
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Interpreting a nuclear decay scheme

From my understanding, this is a decay scheme that shows the percentage of each energy level at which the disintegrated mother nucleus has reached after the disintegration has occurred. But what do ...
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What is the experimental evidence that the nucleons are made up of three quarks?

What is the experimental evidence that the nucleons are made up of three quarks? What is the point of saying that nucleons are made of quarks when there are also gluons inside it?
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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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“Internal conversion,” but with scattering of a real photon?

In internal conversion, a nucleus undergoes an electromagnetic decay, but with some probability it actually ejects a preexisting electron (most often a K-shell electron) rather than emitting a photon. ...
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1answer
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How in Cesium 137 spectroscopy Barium X-rays being detected?

Iv been looking at gamma ray spectroscopy of late for a project that I am currently researching and going to be doing in the lab, but what I cannot seem to figure is how the barium x-rays are being ...
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2answers
47 views

Confusion regarding the orbital angular momentum of mesons in an excited state

I came across the statement that Mesons can have a spin of a whole number (e.g. 1 or 2) instead of the regular 0, as a result of the orbital angular momentum they have in their excited states, with ...
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Spin-parity states of $^{17}O$ and $^{19}O$

I am trying to understand a problem in a subnuclear physics course. The question is the following: The biggest difference between the low-lying states of $^{17}O$ and $^{19}O$ is that $^{19}O$ ...
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1answer
38 views

Nuclear Instability and Q value in Alpha decay

Alpha decay: $(Z,A) \rightarrow (Z-2,A-4)+ ^4_2He $ According to the book: "Nuclear and particle physics" by Williams, $Q_\alpha$ is the measure of available energy to permit an alpha decay. It is ...
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1answer
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confusion regarding energy levels of the nucleus of a Sodium atom [closed]

In my textbook I was asked to compute the wavelength of a photon emitted as the nucleus of a Sodium atom pass from the first excited level to the base level. I got the formula itself right, but ...
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Magnetic field record set with a bang : Can peak magnetism last more than microseconds?

I have read a couple days ago, about the spectacular 1200T magnetic field record set by Shojiro Takeyama and his team at the University of Tokyo. Since the output peak only lasts for a couple ...
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Which structure function is G(x)?

I found a question about structure functions where they ask what is the $F_2(x)$, $xF_3(x)$ and $G(x)$ shape as a function of $x$ (for a given $q^2=10$ GeV$^2$) and also as a function of $x$. I found ...
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1answer
28 views

Two-nucleon coupling: symmetrization postulate

I have some trouble understanding isospin symmetry. If we consider a system of a proton and a neutron as two different iso-states of a nucleon and we wish to write the wave function, do we have to ...