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

learn more… | top users | synonyms (2)

3
votes
3answers
226 views

Theoretical Stability of “AB-matter”

Alexander Bolonkin has proposed the possibility of manipulating nucleons to produce stable, macroscopic structures of nuclear matter at zero pressure (which he calls "AB-matter"), by analogy with the ...
3
votes
2answers
241 views

How clean will first generation fusion reactors be compared to fission reactors?

Googling the topic seems to indicate that fusion reactors will produce less waste and less toxic radioactivity, but this fact never seems to be mentioned during the current debate over nuclear power. ...
3
votes
2answers
140 views

Neutron decay and particles

On this picture you can see that this $d$ quark turns into $u$ quark and makes this $W^-$ boson. $W^-$ then apparently turns the anti-electron neutrino, $\bar{\nu_e}$, into an electron, $e^-$. My ...
3
votes
2answers
665 views

How were the heavy elements from iron to uranium made? [duplicate]

Possible Duplicate: Age of the Earth and the star that preceded the Sun How were the heavy elements from iron to uranium made? References: ...
3
votes
2answers
3k views

Strongest force in nature

Possible Duplicate: What does it mean to say “Gravity is the weakest of the forces”? It is said nuclear force is the strongest force in nature.. But it is not true near a black ...
3
votes
1answer
261 views

The original thorium reactor?

With lunar thorium being common, and heavier than iron or nickel, does earth's core have the the occasional nuclear reaction?
3
votes
3answers
120 views

The role of W bosons in the weak nuclear force and beta decay

I am a beginner Physics student and I am studying the weak nuclear force and how particle interactions work. Now, from my book and the Feynman diagram, I learned that a neutron can change into a ...
3
votes
3answers
208 views

Radioactive decay - What mechanism decides when an unstable nucleus decays?

My first question on Stackexchange (if it is formatted wrong or something please tell me so I know in future) - here it is: Given an unstable nucleus (exactly which nucleus is not particularly ...
3
votes
1answer
177 views

Do atomic nuclei have fixed orientation and position with respect to the electron cloud?

Does the nucleus of an atom of any element (besides protium) maintain a particular orientation in relation to its electron cloud? Does it bounce around within its cloud? Can it be ejected from its ...
3
votes
2answers
1k views

Effect of temperature on radioactivity?

I'm researching the effect of temperature on uranium radioactivity, however I can't find any solid empirical evidence to prove the notion that temperature does not affect radioactivity. Can anyone ...
3
votes
2answers
413 views

How much radiation exposure in the US was caused by the 105 nuke tests in the Pacific?

Between 1947 and 1962 the US conducted 105 tests of nuclear weapons in the "Pacific Proving Grounds". I'm wondering how much radiation exposure resulted on the west coast of the US. These were part of ...
3
votes
2answers
281 views

Why are neutron absorption cross sections high at low incident energy?

For example, U-235 fission cross section looks like this: As I understand it, the resonances peaks correspond to discrete quantum states of the excited compound nucleus. As you go higher, the ...
3
votes
3answers
106 views

Why do nuclear weapons create a blast wave?

As far as I know, in a nuclear explosion the energy is released in the form of radiation (neutrons, gamma rays, alpha particles and electrons), light and heat. There isn't a chemical reaction that ...
3
votes
2answers
158 views

About Nuclear magnetic resonance

I'm trying to understand the basic principles of Nuclear Magnetic Resonance reading this link but I have some doubts: 1) I have ever known that when protons aren't in a magnetic field, their spins ...
3
votes
2answers
3k views

Would being underwater help survive a nuclear bomb?

If I jump in my pool, on the river near my house knowing that a nuclear bomb, or atomic or H-Bomb exploded around 10 km from my house, would I survive? The way I see it is that water will protect me ...
3
votes
1answer
65 views

pp chain gamma decay / intermediate state

Based on the first equation at http://en.wikipedia.org/wiki/Proton%E2%80%93proton_chain_reaction $$_1^{1}H+_1^{1}H \to _2^{2}He+\gamma$$ Is it correct to say that in the P-P chain two hydrogen atoms ...
3
votes
2answers
645 views

Stable Nuclei - Deviation from equal protons and neutrons

While studying the semi-empirical mass formula for nuclei, I came across an "asymmetry term" whose function, as far as I understand, is to build in the fact that nuclei "prefer" to have equal numbers ...
3
votes
1answer
492 views

Should the expression for energy conservation in alpha decay include the mass of electrons?

Let $M_P$, $M_d$, $m_\alpha$, $m_e$ and $Q$ the mass of the parent nucleus, daughter nucleus, alpha particle, electron and the disintegration energy, respectively. I understand that applying ...
3
votes
1answer
67 views

The synthesis of $^{254}\text{No}$

How is $^{254}\text{No}$ synthesised? Could you explain the reaction where it is preceded by $^{208}\text{Pb}(^{48}\text{Ca}, 2\text{n})$? References to articles are well enough—I was somehow unable ...
3
votes
1answer
847 views

What is the relationship between earthquakes power and nuclear explosions?

What is the relationship between earthquakes power and nuclear explosions? How to compared power of earthquake with nuclear explosion?
3
votes
1answer
266 views

How do people get the proton number for each element from experiment?

How did people determine the proton number for each element from experiment in each decade of 20th century?
3
votes
3answers
260 views

Ratio of radiation sources in the uranium cycle

Sorry, I know y'all are probably getting a lot of questions re: Fukushima, but I had a very specific one and no-one has been able to answer it. I am specialised in medical radiation, and have been ...
3
votes
2answers
94 views

What's the slowest nuclear decay rate that's been measurably linked with a narrow energy linewidth?

As was explained in the question What is the relation between the half-time and the line-width of a radioactive nucleus?, the half-life $\tau$ of an unstable nucleus is related to the linewidth ...
3
votes
1answer
52 views

What does 'channel' mean?

I see many plots like the following that graph counts per channel, I know what a 'count' is, but I don't know what a 'channel' is. Could somebody please explain to me? My guess is that it is that ...
3
votes
4answers
155 views

Can neutrons be synthesized purely from protons and electrons?

Can neutrons be synthesized purely from protons and electrons? Note: I'm looking for reactions that do not require neutrinos or any particles besides just protons and/or electrons as reactants.
3
votes
1answer
80 views

What is relationship between Quantum tunnelling and Gravitational potential energy of stars?

Are there a direct mathematical relationship between Quantum tunnelling and Gravitational potential energy of stars? The true source of the Sun's energy was shown by Hans Bethe to be nuclear fusion ...
3
votes
3answers
815 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 ...
3
votes
2answers
1k views

How is energy produced in Alpha emission (radioactivity)?

In the above Alpha decay reaction, we get thorium by the alpha decay of uranium with an alpha particle. But we also get energy of amount Q by this process. And according to my course books, this Q ...
3
votes
1answer
491 views

“Dynamic Albedo of Neutrons” and all these Farnsworth fusors

I've checked specs of Russian "Dynamic Albedo of Neutrons" module on Mars MSL rover - it can do 10^8 neutron pulses at 10 pulses per second. It works on D-T reaction in tiny linear accelerator, and ...
3
votes
1answer
476 views

Phase space suppression

In talking about production/decay processes, I've heard people speaking of decay modes or cross sections being 'phase space' suppressed. For example, a two body final state is more likely to occur ...
3
votes
2answers
266 views

Pressures Necessary for Carbon Detonation

Carbon detonation is a characteristic event of Type 1a Supernova (EDIT: where an accreting white dwarf near the Chandrashankar limit of 1.4 solar masses explodes), an extremely important standard ...
3
votes
3answers
1k views

Does the Breit Wigner formula apply to intermediate virtual particles?

Breit Wigner Formula describes the cross section for interactions that proceed dominantly via a intermediate particle (O*) A+B → O* → C + D: $$σ = \frac{2\Pi}{k^{2}}\frac{Γ_{i}Γ_{f}}{(E-E_{o})^{2} + ...
3
votes
1answer
125 views

Proton-Neutron Lattice as a form of matter?

Would it be possible for a lattice of protons and neutrons (I'm picturing a plane of hexagons in my head) to exist bound by the strong nuclear force (not gravity)? I know that the strong force losses ...
3
votes
1answer
265 views

Can stable nuclei theoretically fission through quantum tunneling?

As I understand it, an unstable nucleus is going to randomly fission because the forces binding it together are momentarily weaker than the electrostatic repulsion of the protons. Given that some ...
3
votes
1answer
477 views

Why the pion does not get mass under Spontaneus breaking of chiral symmetry, but the quarks do?

Some sources state that when the mass of a quark goes to zero, it allows for Spontaneous Breaking of Chiral Symmetry and gets a constituent mass of about $200\, \mathrm{MeV}$. Other sources state ...
3
votes
3answers
615 views

If there is a meltdown at the Fukushima reactors, would the control rods melt also?

According to the reports, the shutdown procedures at all the Fukushima reactors were successful, and all the control rods were fully inserted. So - if there was a meltdown, would the control rods ...
3
votes
1answer
306 views

Why are atomic quadrupole moments calculated using nuclear spin?

It's my understanding that electric quadrupoles interact with the gradient of an electric field, and I understand roughly how this works. I am trying to calculate the interaction between an atomic ...
3
votes
1answer
157 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 ...
3
votes
1answer
101 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 ...
3
votes
1answer
242 views

What determines the distribution of the energy between the beta-particle and the neutrino in beta decay?

When beta-decay occurs an electron or a positron is emitted along a neutrino or an antineutrino. The energy spectrum of the beta particles is continuous because, as I read, the energy is shared ...
3
votes
2answers
1k views

Nuclear Spin of Sodium 23

I am actually calculating the nuclear spin of Sodium 23. Here we have 11 protons and 12 neutrons. Now both the nuclei are short of the magic numbers. When I use the shell model for protons and ...
3
votes
1answer
584 views

Why does the addition of paramagnetic ions decrease the spin lattice relaxation time of protons?

My question pertains to NMR (nuclear magnetic resonance). $T_1$, the spin lattice relaxation time of protons in water is about 2.5 seconds. If you add some $CuSO_4$ (copper sulfate) to the water the ...
3
votes
2answers
453 views

Proton-proton bound state

There is something unclear for me. We say that the deuterium is a proton-neutron bound state of orbital angular momentum L=0 and of total spin S=1. I don't understand why can't we build such a state ...
3
votes
1answer
433 views

Why is the total interaction cross section larger for incident particles with lower energy?

The cross section of a nuclear interaction is a measurement of the probability of that interaction occuring. These probabilities are typically presented in terms of barns ($10^{-28}$ m$^2$) as a ...
3
votes
2answers
2k views

Why is the binding energy per nucleon not zero for hydrogen atom?

The lone proton has not to be worked on against any electrostatic force. So where does the energy come from? What is mass defect for a hydrogen nucleus?
3
votes
1answer
237 views

The vacuum as trigger

Do the apperance in the atomic nucleus of virtual matter-antimatter particle pairs play a role in the random nature of radioactive decay?
3
votes
1answer
205 views

$\frac{1}{\sqrt{2}}$ (|Independent particle Model⟩+ |Strong Interaction Model⟩)?

What is an adequate way to understand this simultaneously. One has the underlying assumption that matter is saturated and has the merit of being able to come up with an accurate formula for the ...
3
votes
1answer
263 views

PNMR, Pulsed Nuclear Magnetic Resonance, Experiment

I am writing a lab report for class on PNMR experiment that we did. How come in this experiment we don't worry about the electron spins in our sample? Aren't the electrons affected by the PNMR machine ...
3
votes
1answer
160 views

Why is Silver-108 unstable

Why is Silver-108 unstable if silver-107 and silver-109 are stable? I found it on crash course but no answer was given.
3
votes
1answer
219 views

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

Consider the following schematics of a Bainbridge mass spectrometer (Source: ...