Neutron Definition and 770 Threads

Say a core collapse event of a massive star occurs, forming neutron star matter in its core. However, the explosion manages to eject enough core mass such that the remnant is below the Chanrasehkar limit. At this point, gravity would no longer be able to overcome electron degeneracy pressure...

It is often said that the paths of light bend, close to a neutron star? What happens if the ray of light is vertical to the surface . If we take into account the spacetime of that inertial body, the constancy of velocity of light holds, (or does it?). But shall we (as outside observers) ever...

There aren't any electrons on a neutron star right? They all get squooshed into the protons to make the neutrons. Am I right about that?

Neutron stars are thought to be rotating in a way that their beems are seen as the pulses. The beems are not aligned with the axis of rotation. What is the current theory about the speed of the axis of rotation? Are they spinning and rotating on both axis?

hi i have a question about nuclear spin if the number of protons and neutrons is even, then my chemistry book says, that the nuclear spin is always zero. i guess that the reason is, that there are always 2 protons and 2 neutrons in one state with opposite spin and therefore the overall...

Hi, 1) I have recently read a book about particle physics and was wondering what could happen if two neutrons hit each other and what energy level would be required for what ever happens? (Since the Pauli exclusion principle does not allow two neutrons to be at the same time and space). 2) If...

Homework Statement estimate light, eletron, neutron beams energy to use 'order - of - magnitude' [eV] Homework Equations E = hv The Attempt at a Solution E = hv where h is Plancks constant and v is frequency and E is energy...

Any one have online documents showing the complete derivation of the both with the numerical solution ?

what is the difference between a neutron star and a black hole?

A neutron is at rest inside a crystalline solid. Can a phonon come along and give up all of its energy to the neutron? Address the question with a graphical solution, i.e. overlay the dispersion curves for neutrons and phonons. For simplicity assume that the solid has a basis of a single atom...

Homework Statement Consider a particle of mass m in the potential V(z)=mgz z>0, infinity if z<0 Show that the wavelength of a neutron (m~1000MeV/c^2) is on the order of 10um. Homework Equations p=(2m(E-mgz))1/2 \lambda=h/p The Attempt at a Solution The most direct solution...

Is it because of charge of an electron that it absobs a photon or even a neutron can absorb a photon?

It is my understanding that when an electron drops to a lower orbital that 2 photons of light are produced. The moving electric charge produces EM radiation just like moving charges in a radio transmitters antenna produce EM radiation. Energy in the form of radiation, heat, or whatever else, can...

Can simple mass accretion turn a neutron star into a Black Hole, or does a BH require temperatures and pressures from the collapsed massive star?

Is my understanding correct that the short term stability of fast neutron liquid metal cooled reactors is based primarily on the thermal expansion of the core, while the Doppler coefficient is far less significant factor, as the Doppler coefficient primarily affects the low energy neutrons? (The...

Hi, before I start this is not coursework or any work attached to my degree but part of an internship at a neutron research facility at a level appropriate for Masters students and higer, so I felt it necessary to post it here rather than the homework section (sorry if I'm mistaken). I've been...

Homework Statement What is the Q value in units of MeV in each of the following processes? i) The spontaneous fission of 232U92 to 145La57 and 87Br35 ii) The neutron induced fission of 232U92 to 146La57 and 87Br35 Explain why heavy nuclei such as 232U92 do not usually undergo fission...

Question is: Determine the neutron and proton configurations of the first and second excited states of: _{20}^{41}Ca which have spin-parities of 3/2^{-} and 3/2^{+} respectively.My attempt at solution: (I haven't encountered a problem quite of this type before so am a little unsure as to how...

I was wondering, does anyone know of a lower limit on the mass of a neutron star from fundamental physics? That is, the smallest it could be before its pressure would make it explode. I don't mean the Chandrasekhar limit, as that's the upper limit for a white dwarf. Neutron stars occurring...

Oh hello. I'm quite uncertain about one of the reasons for the discovery of the neutron. Apparently, the neutron is supposed to be the radiation released by alpha particles hitting Beryllium. When the radiation hits Paraffin wax, the paraffin wax releases protons. At first, people thought that...

I refer to the last paragraph of http://physicsworld.com/cws/article/news/46592 quote: A few hundred milliseconds later, the neutron is captured by a proton to form a deuteron Can someone please explain how a proton captures a neutron or provide links to articles describing this

Yeah it's true, I heard him talking all about it tonight. He said he came up with the theory for it a while ago and he heard of it recently then he knew he was right. Among other things, he briefly said he connected quantum mechanics and consciousness. Then to top it off he said physicists...

Most common isotopes of He has 2 neutrons, Li has 3 neutrons and so on right, until Z increases to higher numbers and we get to elements like iron, where the nucleus doesn't have equal numbers of protons and neutrons anymore. But why isn't the number of protons and neutrons equal in the most...

So I have been reading about the cross section of neutron capture and have been reading about how the cross section for neutrons in a given material depends on neutron energy, the most important factor obviously. But I have not seen as much information on how, for a neutron of a given thermal...

Homework Statement Deep in space, two neutron stars are separated (center-to-center) by a distance of 18 X 106 km apart. Neutron star A has a mass of 153 X 1028 kg and radius 52000 m while the neutron star B has a mass of 159 X 1028 kg and radius 72000 m. They are initially at rest with...

Like the question says, would a neutrino be stopped by the very high density matter in a neutron star? IH

Homework Statement A thin target of lithium is bombarded by helium nuclei of energy E0. The lithium nuclei are initially at rest in the target but are essentially unbound. When a Helium nucleus enters a lithium nucleus, a nuclear reaction can occur in which the compound necleus splits apart...

If a super-duper-hyper-energetic particle like the OMG particle (refer http://en.wikipedia.org/wiki/Oh-My-God_particle) were to impact the surface of a neutron star, could the tremendous impact density it creates lead to the beginnings of an embryonic black hole that would (slowly/quickly?)...

does neutrons have electromagnetic force? I mean it is the electromagnetic force which allows particles to feel each other in the first place during detection process, but neutron is neutral with no charge so does it possesses it?

Problem statement How fast must a neutron be traveling relative to a detector in order to have a measured kinetic energy that is equal to its rest energy? An "attempt" I know Ek = mc^2 - m0c^2 But if Ek = m0c^2, wouldn't the two terms cancel out from this equation? I am having trouble...

If you add up the g-factor for the electron, the proton and the neutron it is not exactly zero. Doesn't this calculate to a magnetic moment for every atom in the universe proportional to it's mass.

Does the absorption cross section to scattering cross section ratio of an isotope vary with neutron energy or stay constant? I have heard that cross sections in general are inversely proportional to velocity (eg the fission cross section of U235 is about 1000 times higher for thermal neutrons...

I keep reading that when a U-238 atom absorbs a neutron it turns into Pu-239. How does that happen? If I'm not mistaken Pu-239 is U-238 plus 2 protons and 2 electrons and minus 2 neutrons. When U-238 absorbs the neutron and becomes U-239 I can see that it can turn into Pu-239 if 2 neutrons decay...

Talking to the point, I need to know how a free neutron interacts with light (or a photon). Or, if they do not interact, the reason behind it. The reason why I am asking this question: Assume that a free neutron is being hit by light. If I assume that light is an EM wave, I can conclude...

I'm thinking about the thermodynamics of electron capture: p + e --- n + v(e) + energy (That is, proton absorbs electron to give neutron, electron neutrino and energetic photons.) This is thermodynamically disfavored given the substantial energy barrier to fusion to a neutron...

I am working on some neutron experiments and have to calculate the heat released in the boron neutron capture 10B + 1n - > Li + Alpha particle The reaction has a Q value of 2.31 MeV. Is this entire energy converted to heat? Also, in the two types of reactions of neutron with Boron...

http://arxiv.org/abs/1101.4298 The missing link: Merging neutron stars naturally produce jet-like structures and can power short Gamma-Ray Bursts Luciano Rezzolla, Bruno Giacomazzo, Luca Baiotti, Jonathan Granot, Chryssa Kouveliotou, Miguel A. Aloy (Submitted on 22 Jan 2011) "Short Gamma-Ray...

I have been reading up on radioactivity (Wikipedia). I keep coming across articles which talk about emission of Neutrons (during Plutonium decay, for example). Now I know alpha radiation is basically Helium-4 nuclei, but that consists of both Protons and Neutrons combined in a nucleus. What...

Ok so my problem is I have absolutely no idea where to start. I have been able to figure out other problems but this I can't get my head around. I am unsure as to the equations I need to use for collisions and how to obtain the correct answer. Homework Statement A nuclear reactor (see...

Neutrons have no charge, and in neutron stars we have matter that is only made of tightly packed neutrons. The mass is very great due to density. If I were to go fetch a baseball sized ball of neutron star matter from a neutron star and lay it on hard concrete ground... Other than making a...

A very simple question, but needs to know proper explanation. Why the neutron scattering from hydrogen is negative while deuterium and almost all other atom has positive scattering?

Homework Statement I have a (numerically calculated) cross section for a neutron scattering from a nucleus which looks like: 1) Am I correct in saying that there are three resonant peaks and these correspond to three different resonant particles? 2) If so, are the lifetimes of the...

Can someone explain what are the implications for the 13 neutron beams that have been observed at Fukushima? How are they created? What will cause more to be created?

Homework Statement How many collisions will be necessary to slow a neutron down from 14.1 MeV to thermal energy (0.0253 eV)? A=24 Homework Equations E'=[(A-1)/(A+1)]^2 x E The Attempt at a Solution The calculation is not an issue- I understand how to use the equation and what...

Basically as the title says, what type of fusion would give the highest number of neutrons for a given amount of power. Also am I correct in assuming that most fusion methods will always produce more neutrons than other neutron sources such as americium-beryllium? (There are probably some...

Hello all. I'm am a first time poster but a long time visitor. I am having a little trouble that I was hoping someone far wiser and more knowledgeable than myself might be able to help with. I've been using MCNP to investigate criticality in a simple geometry consisting of a central natural...

Will black dwarfs eventually quantum tunnel into neutron stars if proton decay doesn't occur?

I'm wondering about the visual appearance of neutron stars up close. Do they continue to emit light like a white dwarf? Can cooled ones be gray or black? The xray emissions from pulsars will not be visible to us. Due to their high mass, they will bend light in a similar manner to a black hole...

In the early universe electrons and protons would combine to form neutrons and few, if any, protons would remain. If the mass difference were greater than the binding energies of nuclei, neutrons inside nuclei would decay leaving no nuclei behind. Does anyone know why the above...

I thought others might be interested in this: http://arxiv.org/abs/1011.6142 As a nuclear physicist, I don't find it surprising to hear that neutron stars are superfluid. Nuclei are superfluid. I'm not clear on the relationship between superfluidity and cooling. Can anyone explain this using...