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

learn more… | top users | synonyms (2)

2
votes
2answers
114 views

Would it be possible to detect nuclear explosion on exoplanet?

How strong would have to be nuclear explosion on exo-planet that orbits some other star for it to be detectable outside of that system. Or it would be impossible due to amount of radiation coming from ...
1
vote
2answers
45 views

Explosive energy in a container [closed]

What happens when the explosive energy of a grenade or a bomb is contained in a container, if you will, and no energy can be released through the container in the form of heat or sound etc...? Just ...
1
vote
2answers
81 views

Radioactive decay law and the exponential model, is it always valid?

The law of radioactive decay reads $$ N(t)=N_0e^{-\lambda t}$$ Is it valid when there is less than 1 nucleus or particle to decay? Obviously, it is nonsense to consider that we have 1/2 of nucleus ...
1
vote
1answer
38 views

Totally antisymetric wavefunction: clarification about terminology

Pauli's Principle says: "The wavefunction of two identical fermions must be totally antisymmetric". I know that, for a antisymmetric wavefunction, $(-1)^L*(-1)^{S+1}*(-1)^{I+1}=-1$ "totally ...
1
vote
1answer
72 views

Parity of a system composed of 2 particles

I have read that for a system of 2 particles, the total parity is given by: $P=P_1 P_2 (-1)^L$ where $ P_1, P_2$= insisec parity of particle 1, 2 $L$ = relative angular moment what's the meaning ...
-1
votes
1answer
62 views

Is the half-life of Primordial Nuclide determine only by the age of the earth? [closed]

Is the half-life of Primordial Nuclide determined only by the age of the earth? Or are their other age defining considerations? The point of the question is to know that the only reason that we have a ...
6
votes
4answers
282 views

About mass defect

Here's how my book explains mass defect: Particles inside the nucleus interact with each other - they feel attraction. The potential energy $U$ of such attraction is negative, because in absence ...
5
votes
1answer
149 views

Problem with shell model and magnetic moment of Lithium-6

I have a problem with the calculus of magnetic moment of Li-6. The configuration of protons is $1p_{3/2}$, and the neutrons' one is the same. I have to add the magnetic moment of uncoupled proton ...
2
votes
3answers
97 views

What makes nuclear binding energy so much stronger than chemical energy

The strong force acting between quarks and responsible for holding protons together is 100 times stronger than the electromagnetic force. How come the nuclear binding energy derived from the strong ...
0
votes
1answer
33 views

Collision of a heavy charged particle with an electron at rest - Deduction

When I was studying Nuclear Physics I saw this formula about interaction of radiation with matter. The book mentioned that when considering a elastic collision of a heavy charged particle of mass $M$ ...
1
vote
2answers
61 views

Which nucleus is the most resilient against gamma-induced fission?

To state the title question perhaps more precisely: What is the largest photon energy $E_{\gamma}$ and the corresponding mass number $A$ and atomic number $Z$ of a suitable nucleus ${}^A_ZX$ ...
12
votes
3answers
2k views

Why do all elements above $\require{mhchem}\ce{Fe}$ not decay to $\ce{Fe}$?

OK, so $\ce{Fe}$ is the most 'stable element'. As such, why do all elements above it not decay into $\ce{Fe}$? In all cases, would it not lead to an increase in binding energy and therefore energy ...
0
votes
0answers
46 views

Nuclear Physics: Eigenvalues of nucleus angular moment

In the shell model of nuclei, when we talk about collective motions, we describe any nucleus deformation, expanding its radius on spherical harmonics base like this $R(\theta,\phi) = ...
0
votes
0answers
37 views

Why are quark up and down an isospin doublet?

I have some difficulties in understanding the isospin of quarks. As far as I am concerned, the isospin formalism is used to express the physical property of electric charge. I mean: what I know ...
12
votes
1answer
155 views

Spallation neutron generation and pure U-238 reactors

Main question: Is it possible to achieve net power generation based on linear proton accelerator and U-238 target? In the proposed reactor design there is a proton beam with energy ~10 GeV, and on ...
3
votes
1answer
117 views

Shell model of an odd-odd nucleus: $^6$Li

Lithium-6 isotope has an approximate magnetic momentum of $0.88\ \mu_N$ in its fundamental nuclear state. I'm trying to find its angular momentum and parity. I found in a standard table: $I=1^+$ and ...
1
vote
1answer
32 views

When and why spontaneous nuclear fission is preferred to alpha emission?

I reasoned as follow: the probability of an $\alpha$ emission $^A_ZX\to^{A-4}_{Z-2}X^{'}+\alpha$ is given by: $T=e^{-G}$ where the Gamow factor is given by: $G\simeq \pi \sqrt{\frac{2\mu ...
1
vote
1answer
42 views

Nuclear fission mechanism: neutron capture

Consider this nuclear fission reaction: $\mathrm{^{235}U+{}^1n\to{}^{236}U \text{ (excited)}\to{} ^{92}Kr+{}^{141}Ba+3{}^1n}$ I have not understand why a thermal neutron ($^1$n with $E\simeq 0.025$ ...
2
votes
3answers
94 views

Tritium decay is spontaneous even if the binding energy of tritium is higher than the binding energy of 3He. Why?

Given this nuclear reaction: $^3_1\mathrm H\to {}^3_2\mathrm{He}+e^-+\bar{\nu}$ and knowing the binding energies: $BE(^3_1\mathrm H)=8.48 \,\mathrm{MeV}$ $BE(^3_2\mathrm{He})=7.72 \,\mathrm{MeV}$ ...
1
vote
1answer
95 views

Would a Nuclear bomb have any effect on the sun that could damage the earth?

I was asked this recently and wasn't sure. The power of the sun is much more powerful than that of a Nuclear explosion but the question was what is the worst that could happen, we are assuming a ...
2
votes
1answer
42 views

Peaks in binding energy per nucleon

Looking at the the binding energy per nucleon chart: I observe peaks for N=4,8,12,16,20,24 while I expected to observe peaks for 2, 8, 20, 28, 50, 82, and 126 because I have heard that in ...
1
vote
1answer
31 views

Original Paper on Slow Neutron Capture by Fermi?

I was wondering what the title of his original publication on Neutron capture was. I've found his Nobel lecture but I want to read his initial publication. A title would be most appreciated. It's ...
4
votes
2answers
101 views

Computer parsable table of nuclides

I am looking for an computer parsable (CSV, XML, JSON, since I didn't find anything, I am happy with almost everything) file (or collection of files) that contains the information you can find in a ...
0
votes
2answers
186 views

Radioactive stability of some nuclei

While studying radioactivity I found that even the most radioactive substances i.e substances with the shortest half lives do not completely degenerate. Suppose there is a 1 mole sample of an ...
1
vote
1answer
44 views

Could someone explain the “revolving frame” to me, as it is used in basic NMR?

I am an undergrad intern at a national lab currently working with a basic proton NMR device. The device consists of two big coils which provide the static magnetic field, and a smaller coil, which ...
1
vote
0answers
25 views

Question: if a nuclear reactor of a submarine explodes will it contaminate the surrounding waters? [closed]

After watching a Naval War movie I began to ask myself this question and I would like to know.
1
vote
1answer
87 views

Nuclear shell model - finite square well

I am trying to make a simplified approximation and solve Schrodinger equation in the finite square well to model the nucleus of Ca (shell nuclear model). The potential is $ V(r) = -V_0$ for ...
6
votes
1answer
116 views

Why a slow moving neutron is required in nuclear plants?

I came across a line that said "an atom of heavy element is hit with a low velocity neutron, otherwise the required reaction would not achieve result". So, why not a neutron of high velocity is ...
1
vote
2answers
56 views

Starting a nuclear reaction

In Chemistry, an amount of energy has to be supplied for a reaction to occur. This energy, known as the "activation energy", breaks up the bonds between molecues in the substance. It is equivalent to ...
2
votes
2answers
73 views

Copper coils for nMRI

Given the lack of financial efficacy in the medical industry, I was wondering if nuclear magnetic resonance imaging would be possible with a copper/silver coil if the use is short 10 second imaging ...
3
votes
1answer
124 views

Velocity distribution in ion source (electron bombardment) for Bainbridge mass spectrometer

Consider the following schematics of a Bainbridge mass spectrometer (Source: ...
-1
votes
1answer
145 views

why countries can't make nuclear bombs? [closed]

Somehow when I google about the nuclear bombs I find a lot of books and resources that seem to explain everything about how those bombs are made. But sometimes I often hear that countries that want to ...
4
votes
0answers
68 views

Why does strong interaction increase with distance?

I read numerous times that strong interaction increases with distance. But how can one actually derive the force-distance relation from the lagrangian (quark field + gluon field + gauge coupling)? ...
2
votes
0answers
100 views

Why is free neutron unstable but free proton is stable?

Aren't they basically made up of the same stuffs (quarks) in almost the same configuration?
3
votes
1answer
98 views

Put yourself in the shoes of Wolfgang Pauli (1930): How could Pauli have narrowed the culprit down to one particle, instead of many?

A while ago, during my introductory physics course, my professor purposefully neglected to tell us about the existence of the anti-electron neutrino in beta decay; he made it an assignment(on our ...
0
votes
1answer
58 views

In what sense can an object in outer space be “on fire”?

The famous "Tears in rain" soliloquy in Blade Runner goes like this: I've... seen things you people wouldn't believe... [contemptuous laugh] Attack ships on fire off the shoulder of Orion. I ...
3
votes
2answers
400 views

Atomic nucleus consisting of only neutrons?

Is it true that the nucleus of all atoms (including radioactive isotopes) contain at least one proton? Is there an atomic nucleus consisting entirely of neutrons? (Let's exclude neutron stars for the ...
0
votes
3answers
149 views

Is the solar energy Infinite?

Is the solar energy coming from the sun infinite and will continue to be radiated to our earth forever? (discarding any outer factors) what's the sun's fuel?
17
votes
6answers
1k views

Which experiment gave scientists reason to believe nuclear fission/fusion produced energy?

Every piece of knowledge in science has a beginning lying in someone's experiment. I would like to know which experiment gave scientists the reason to believe nuclear fission/fusion existed and was ...
0
votes
1answer
33 views

Behavior of Pion-Mediated Nuclear Force before Electroweak Symmetry Breaking?

When Chiral Symmetry was exact, as it was before EWSB due to the lack of mass terms for quarks, would the residual strong force have infinite range? Related to this, does the Negative Beta Function ...
2
votes
1answer
39 views

Radioactive half lifes

What is the typical half life of material released from nuclear fission? This is a question I received for yr 12 physics and I can't find a proper answer telling me what the material released is and ...
1
vote
2answers
73 views

How to calculate the energy freed in the reaction: $^{10}_5Be +\space ^2_1H \rightarrow \space^{11}_5B + \space ^1_1H$?

I have the following reaction: $^{10}_5\mathrm{Be} +\space ^2_1\mathrm{H} \rightarrow \space^{11}_5\mathrm{B} + \space ^1_1\mathrm{H}$ And I know that I have to use the formula: $E = \Delta m\cdot ...
1
vote
0answers
39 views

Subnuclear physics vs wave function

This question is more a philosophical question than a physics one. When we appreciate particle physics we study that in order to explain some experimental results we have to introduce a new particle ...
5
votes
1answer
79 views

Why do excited states in $^4$He not decay by photon emission?

Here's a level scheme for the $^4$He nucleus (source; click image to see full size): Notice that all of the confirmed decay modes are by disintegration — emission of a neutron, proton, or deuteron. ...
2
votes
0answers
53 views

De-excitation and vibrational frequency

By utilising energetic beams of particles it is possible to set atomic nuclei into vibration. For a certain nucleus the subsequent de-excitation results in the emission of photons of energy $1$ $MeV$. ...
3
votes
3answers
271 views

How do substances with like charges repel each other?

I have read in a number of places how substances with opposite charges attract each other: The excess electrons in the one substance repels the electrons in the other substance so that they move away ...
0
votes
1answer
51 views

What kind of research will go in nuclear fusion power once the commercial power plant is designed and implemented? [closed]

once the commercial nuclear power plant is built for electricity production , after this what kind of research does scientists do in nuclear fusion power. Why I am asking this question is ITER is ...
2
votes
1answer
27 views

Periodic Table and strong fields at high Z

There is a known "phenomenon" recalled by Greiner et al. in several of his books related to hypothetical elements with Z>172: in some point arount this Z, the nuclear field is strong enough to pop out ...
0
votes
1answer
59 views

What is the half-life threshold for an isotope to be considered stable?

What minimum half-life an isotope should have to be considered stable?
4
votes
1answer
111 views

Why 3He(n,p)3H nuclear reaction proceeds but 3He(n,gamma)4He heavily suppressed?

The neutron capture reaction 3He(n,p)3H is very useful for neutron detection as the Q value of ~700keV is converted to kinetic energies in the produced p and 3H. These charged products can then ionize ...