Nuclear physics is the study of the composition, behavior and interaction of atomic nuclei and their constituent parts.
-1
votes
0answers
27 views
The physics of Hartree-Fock convergence or non-convergence [closed]
I'm new here so please forgive me if I lack proper stack exchange etiquette.
So, I was wondering if anyone here could provide insight on a problem that I am running into with with a Hartree-Fock ...
1
vote
2answers
95 views
Under what conditions is a pure fusion nuclear bomb possible?
Is it possible to build a pure fusion and powerful nuclear bomb?
(because due to the harsh conditions of enriched uranium, I would guess most of today's world countries will want to build pure fusion ...
3
votes
1answer
107 views
Why does it take so long to make a nuclear bomb?
So as I know nuclear bombs are derived from fission reactions: By providing the nucleus with enough power to trigger a chain reaction. If uranium was present why does it take so much to make a nuclear ...
1
vote
2answers
36 views
Nuclear Binding energy
The nuclear binding energy, is the energy that is needed to seperate the nucleons in a nucleus. And binding energy is also defined as the energy given out when a nucleus forms from nucleons.
Also ...
2
votes
1answer
30 views
Fusion vs. Fission
I understand why fission generates large amounts of energy when the nucleus is split, but then why does fusion generate such large amounts of energy. If fission releases energy when some mass is lost ...
2
votes
1answer
42 views
Gaseous fission: Has it even been demonstrated experimentally?
I've been reading quite a bit about gas-core reactors, a theoretical reactor design where the fissioning of Uranium(along with Plutonium & possibly Thorium)occurs in gas phase. The result is that ...
0
votes
0answers
36 views
What does $\mathrm{A}_r(\mathrm{H})$ represent when calculating the average natural weight of an elemental atom? [migrated]
I have a question that explains the weights and abundances of various hydrogen isotopes, and the question concludes by asking to:
Calculate the atomic mass of hydrogen $\mathrm{A}_r(\mathrm{H})$ ...
6
votes
2answers
543 views
How do you build a nuclear reactor in your garage?
When I came across this link earlier today, I was astounded. Nuclear reactors are immensely complex devices that took scientists years to develop, and are usually housed in huge facilities. The link ...
1
vote
2answers
40 views
Theoretic Mass Energy Conversion?
say you had a large quantity of a heavy element such as uranium... AND you put a massive amount of energy into it, so that it began to undergo nuclear fission and transformed to a significantly ...
3
votes
1answer
165 views
What has $E = mc^2$ to do with nuclear powerplants?
In life, when you talk about nuclear energy, there always happens to be a guy who says that famous Einstein's equation. "Yeah, they just convert mass to energy, $E = mc^2$ ya know?"
When I think ...
1
vote
1answer
63 views
Proton mass and Weizsäcker's formula
I'm so confused in the use of nuclear masses and atomic masses.
I have two questions.
From the book "Outline of Modern Physics" by Ronald, I understand that the semiempirical mass formula ...
2
votes
1answer
78 views
One body harmonic oscillator states expressed in terms of creation operators
I am reading trough chapter one of Moshinsky's "The harmonic Oscillator in Modern Physics". However i am having some trouble with the mathematics in section 8 of chapter 1. I will sketch a summary of ...
5
votes
1answer
103 views
Can open, unsafe nuclear fusion reaction burn the atmosphere?
I happened to hear people saying that the nuclear fusion bomb tests could set the atmosphere on fire. I have some serious doubts about that - but I have no facts.
Nuclear fusion reaction requires ...
-6
votes
1answer
90 views
What's gonna happen if a nuclear bomb explodes nearby? [closed]
I live in the capital, 10 km from its center on the 9th floor, my windows facing the opposite direction will I still see a flash? Will I hear something? How loud will it be? How fast would I die? If I ...
6
votes
2answers
109 views
Why is Helium-3 better than Deuterium
I see that many websites and magazines with physics thematic are pretty excited about mining Helium 3 isotope on the Moon. But this seems to be a very hard-to-get resource. For more than one reason:
...
2
votes
2answers
76 views
Harmlessness of a pure alpha decay particle
From my high school physics class I remember that there are some particles which exhibit pure alpha decay (i.e. alpha decay to there stable isotope), like Po-210, Po-211 and Bi-209.
What I also know ...
1
vote
2answers
47 views
$Q$-value in nuclear reaction $^{9}Be\left(\gamma,n\right)^{8}Be$
I have two questions.
First, I understand that in a nuclear reaction
$$Q:=K_{after}-K_{before}\equiv E_{0,before}-E_{0,after} \qquad (1)$$
where $K$ is the total kinetic energy, and $E_0$ is the ...
-1
votes
1answer
52 views
Calculate energy from an reaction [closed]
I'm trying to calculate the released energy from a reaction.
The radioactive substance polonium decays according to this formula:
$$^{210}_{84}\mbox{Po} \rightarrow \mbox{X}+^4_{2}\mbox{He} $$
At ...
-3
votes
0answers
57 views
How long would it typically take to develope nuclear weapons these days? [closed]
This question is a bit related to politics.SE too.
These days there's a lot of concern about development of nuclear weapons in countries that are believed by United States to support terrorism.
As ...
3
votes
2answers
51 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 ...
1
vote
2answers
56 views
Electric potential energy after nuclear fission
We have a uranium-236 nucleus that fissions into two equal fragments, and I'm supposed to find the electrical potential energy just as the two fragments split apart. No other information is provided.
...
-2
votes
0answers
37 views
The Hartree solution of two harmonic oscillator coupled by potential $V \propto ({\bf r}_1-{\bf r}_2)^2$ [closed]
$H={\bf p}_1^2+{\bf p}_2^2+{\bf r}_1^2+{\bf r}_2^2+x({\bf r}_1-{\bf r}_2)^2$.
$x$ is the coupling factor.
1
vote
1answer
54 views
what is the magnetic quadrupole operator?
To find magnetic or electrical moments in quantum theory we must calculate the expectation value of an appropriate operator. the dipoles operator are similar and is easy to find but the magnetic ...
0
votes
0answers
38 views
What is the magnetic quadrupole moment of a nucleus in cylindrical coordinates?
What is the magnetic quadruple moment of a nuclei in cylindrical coordinates?
The quadrupole moment of a nucleus is zero in spherical coordinates but in the cylindrical coordinates it can't be ...
27
votes
2answers
3k views
Why can Hiroshima be inhabited when Chernobyl cannot?
There was an atomic bomb dropped in Hiroshima, but today there are residents in Hiroshima. However, in Chernobyl, where there was a nuclear reactor meltdown, there are no residents living today (or ...
-4
votes
0answers
35 views
Approximately how much would a LFTR cost? [closed]
Would anyone happen to know how a LFTR costs?
Please could you include the efficiency and payback time.
0
votes
2answers
36 views
Finding radioactive nucleus given table of values
Question Measuring the number of decays per minute $N(t)$ of a radioactive source every four days we have that: $N(t=0):=N_0=200$, $N(t=4)=141$, $N(t=8)=100$, $N(t=12)=71$, where $t$ is measured in ...
3
votes
1answer
40 views
Containement system of a nuclear reactor: role of the water moderator
In a modern nuclear reactor for example a PWR there are multiple containment systems which prevent the release of radioactive material into the environment and shield the environment from the ...
0
votes
1answer
48 views
Speed of neutrons in a nuclear reactor
How fast (in $\frac{\mathrm{m}}{\mathrm{s}}$) are typical neutrons before and after slowing down in a nuclear reactor (with U-235 and $H_2O$ as moderator)? Do you have any reference for the values?
2
votes
1answer
55 views
Adding many more neutrons to a nucleus decreases stability?
If you take any large nucleus and add protons to it, the electrostatic repulsion between them will make the nucleus more unstable, because the electrostatic force between them is more repulsive at a ...
6
votes
2answers
156 views
Radioactive Decay
Problem:Nuclei of a radioactive element $\Bbb X$ having decay constant $\lambda$ , ( decays into another stable nuclei $\Bbb Y$ ) is being produced by some external process at a constant rate ...
0
votes
0answers
46 views
Find mass of Plutonium in alpha decay [closed]
I did:
$$\Delta mc^2 = (m_{Pu}+m_{U}+m_{He})c^2$$
$$\frac{5.24 \times 10^6 eV}{(3 \times 10^8)^2} = m_{Pu} + 235.043924 + 4.002603$$
$$m_{Pu} = 239.0465$$
But answer is 239.052157, slightly ...
3
votes
1answer
53 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 ...
6
votes
2answers
139 views
What stabilizes neutorns against beta decay in a neutron star?
Free neutrons are known to undergo beta decay with a half-life of slightly above 10 minutes. Binding with other nucleons stabilizes the neutrons in an atomic nucleus, but only if the fraction of ...
0
votes
1answer
173 views
Energy conservation in nuclear reactions and radiactive decay
Reading "Fundamentals of Nuclear Physics" by Atam P. Arya, I understand that in a nuclear reaction, let say $x+X \to y+Y$ meaning that "when a particle $x$ strikes a target nucleus $X$, the outcome of ...
4
votes
1answer
85 views
Why is a pion so light compared to a neutron or proton?
A pion is made out of a pair of up and/or down quarks. A neutron or proton is three up or down quarks. So naively I'd expect a pion to be about 2/3 the mass of a nucleon.
In fact it's less than 1/6 ...
1
vote
1answer
90 views
What is the lowest possible theoretical temperature that nuclear fusion can occur at?
I am not talking about the pseudo-science of so called cold fusion I am interested in what temperature you can get away with to produce fusion reaction. I was thinking in terms of micro-fusion or at ...
0
votes
3answers
43 views
Interaction photons-matter and dimensional analysis
I know that when photons pass through matter, the law that describes the intensity in function of the thickness is:
$$I(x)=I_0 e^{-\mu x}$$
where $\mu = \rho \frac{N_a}{A} \sigma$ and ...
1
vote
2answers
79 views
Alpha particle and helium nucleus
The symbol for the alpha particle is α or $α^{2+}$, it can be written as $He^{2+}$.
What I want to know is that, are they same? I mean alpha particle and helium nucleus are same or any subtle ...
1
vote
1answer
78 views
Ratio of Size of Atom to Size of Nucleus
I have the following problem:
In nuclei, nucleons exists in nuclear energy levels and in atoms, electrons exist in atomic energy levels. The order of magnitude of nuclear energy is 1MeV whereas ...
2
votes
1answer
62 views
$\require{mhchem}$ $\ce{\beta^{+}}$ decay for $\ce{_9^18F}$, computing $\Delta m$
For the decay:
$$\require{mhchem}\ce{_9^18F\to_8^18O +e+ +{v}}$$
To compute $E$, I need $\Delta m$, the provided answer looks like:
$$m_i = 18.000938~u$$
$$m_f = 17.999159~u + 2~(5.49 \times ...
8
votes
4answers
188 views
Why are alpha particles such a prominent form of radiation and not other types of nucleon arrangement?
It is said in many textbooks that alpha decay involves emitting alpha particles, which are very stable. Indeed, the binding energy (~28.3 MeV) is higher than for $Z$-neighboring stable isotopes. But ...
0
votes
2answers
89 views
Bremsstrahlung: why is electron slowed/stopped by the positive nucleus?
I can't understand why the electron is slowed/stopped by the nucleus.
The electron is a negative charge and the nucleus is positive... they should attract each other...
-2
votes
1answer
79 views
Is speed of electrons in atoms a constant during explosions? [closed]
E.g. in exploding nuclear bomb or some other big explosions.
I mean if the speed of electrons as waves/particles is a constant or changes according to other "forces" involved?
5
votes
3answers
225 views
We're all star dust?
OK so we've all heard of this from Carl Sagan, Lawrence Krauss and others and we know the argumentation, I don't refute that. There are other examples, for instance I once calculated (this was before ...
6
votes
0answers
66 views
Does quark color contribute to “spin degeneracy” for QGP calculations?
Like the title say, does quark color matter in counting contributions in a early universe plasma (QGP), as when adding up the total plasma energy density, or is it just spin? The book I have (Pathria) ...
4
votes
2answers
159 views
Mass defect- From where mass is being lost?
As a school student, I have wondered while studying mass defect the following mysterious problem
My assumption
Just like a car's mass is constituted by each part of it(i.e total mass of car will be ...
2
votes
1answer
52 views
Ground states in the shell model for odd-even nuclei
I understand that even-even nuclei (Z and N number) have zero spin because of pairing.
Even-odd nuclei have the spin of the odd nucleon, and parity is given by $(-1)^L$ - so my question is, ...
2
votes
1answer
78 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 ...
2
votes
1answer
42 views
Why did Otto Hahn use neutrons to generate transuranium?
In physics textbooks with chapters about nuclear fission there is often a historical introduction about Otto Hahn. That he tried to generate transuranium but discovered the nuclear fission.
If you ...
