Neutron Definition and 746 Threads

What is measured in a fast reactor for power calculation : fast neutron flux or overall ( fast + thermal) neutron flux ? My doubt is : The fission chambers used for measuring neutron flux undergo chemical reactions due to which type of neutron : fast or thermal ?

I need so advise on SPH open source code to use to look at mergers and rotating objects... if anyone has some links or tutorials? Thank you!

Hey, So i just read 2 articles, the first talked about the mathematical problem of 'packing', IE how many smaller objects of the same size can fit inside a shape without overlapping or covering the boundaries of the shape. and the second article was talking about a recent neutron star that...

Hello. I am wondering what are the properties of matter at the core of a neutron star. I read that it could be quark matter of strange matter, but overall uncertain. How can strange matter form if strange quarks decay very quickly into up quarks (the state of matter would last very shortly), and...

Thank for all if you understand my ideal. My problem is i don't know what's neutron which cause of fission in critical accident? seem it must be have the first neutrons, and then reaction fission occurred ? eg The critical model in some nuclear accident, what is neutron source? The...

and successfully fission. let's say a neutron approaches the spherical nucleus from a particular distance. its possible route to the nucleus has a conical shape. how far from the center can it strike and still fission? If it just nicks it just inside a tangent line will it fission?

ok, this is the question: neutrons scatter elastically at 1.0MeV. after one scattering collision, determine what fraction of neutrons will have energy of less than 0.5 MeV if they scatter from: a. hydrogen b. Deuterium c. Carbon-12 d. Uranium-238 solution process... the basic...

just thinking cross sections here. a neutron that is freed as a result of a fission of pure U235. travels @c/10(fast!) will its trajectory be perturbed by the gravitational force emitted by a nearby nucleus, or do things on the quantum level work differently?

a. it rotates faster b. it is smaller c. it is more luminous d. it has stronger pulses I'm stumped on this practice question for my final. I'm thinking that a. and d. contradict each other since doesn't an older, slower rotating neutron strong emit longer, stronger pulses? C. seems to...

1. How much energy is released during the fission of one uranium-235 nucleus? 2. e=mc2 lol :smile: 3. I thought of putting them together but then how to separate them? 1.67495×10-27+3.903 05×10–25×c2=1.7539207313048996244767495×10-7 By the way, the answer is 4.73×10-11

Homework Statement An open cluster is observed to contain 1000 stars. Clusters contain many more low mass stars compared to high mass stars, reflecting the star formation process. This depen- dence of the number of stars formed in a given mass range is expressed in the so-called initial mass...

Hello all, Does anyone know the weight of a neutron? Or, better yet, does anyone know offhand the weight of hydrogen subscript 2 (hydrogen isotope with two neutrons)? Thanks!

I have just attended a talk, where the speaker (a professor in Hong Kong University) claims that neutron stars don't collapse due to "nuclear forces". He further explains that those nuclear forces are residual strong forces (i.e. exchange of pions). However, the mainstream saying (according to...

How do you strip a neutron from a particle? Thanks

Could anyone provide a concise explanation of the function of a discriminator in what is basically a, Detector => Pre-Amp => Amp => Discriminator => MCA (Multi-Channel Analyzer), circuit. I have a basic knowledge of electronics, but I'm still new to this. Thank you!

Hello all, this is my first post so hopefully its not overly foolish. I propose a mechanical piston driven by a cylinder that is filled with Uranium Hexafluoride and an inert gas (Nitrogen?). As the piston descends, the the UF6 is compressed and the neutron flux spikes. The increased...

Hello, So I'm reading about isospin in Griffith's Introduction to Elementary Particles, but the concept seems rather fishy, and I'm not quite sure what to make out of it. For example, if p and n (proton and neutron) are seen as different states of the same system, then what does...

Is there a well-established theory for temperature and cooling processes of neutron stars as a function of time?

Hi, I was reading about PWR control system and I saw that control rods are stainless steel tubes encapsulating a Hafnium absorber material , it has Excellent mechanical properties and exceptional corrosion-resistance properties allow its use in the harsh environment of a pressurized water...

Dear Forum, I have been given a DT fusion spectrum where neutrons are produced in the following reactions, DT = 14.1 MeV DD = 2.45 MeV TT = 0-9.8 MeV (three body spectrum) The spectrum is given in the form dN/dE. I have converted this spectrum into the dE/dE by multipling the...

Can anyone tell me, in detail, about Neutron - Proton interaction. Newbie here, so please use easy words(i know enough about quarks and gluons as well as strong interaction forces)

I recently saw the Evaluated Nuclear Data File provided by Brookhaven national lab., where in i saw the plot of "Neutron Energy Vs cross section (total)" for different elements. http://www.nndc.bnl.gov/sigma/index.jsp?as=1&lib=endfb7.0&nsub=10 Now what i am interested in is, can we derive or...

I have a scientific background in materials science. However this is one type of material that we don't exactly learn about! Let's say you have a neutron star approaching a comparable mass black hole. As the neutron star approaches the event horizon for such a comparable black hole, tidal...

Dear all, I am gautama currently pursuing my M.Tech in Fast breeder reactor at IGCAR. The project is based on the fuel sub assembly bowing due to thermal, swelling gradients. Using a FEM software ANSYS i have modeled the Sub assembly, but i am not able to give swelling parameter in ANSYS...

Dear friend, I am getting confused in this question;what i learned till now is that number of proton+number of neutron=atomic mass. But while searching the net i got this equation atomic mass = mass a x fract a + mass b x fract b. can anyone tell me which is the correct (not approximate)...

Homework Statement In a reactor, we're making 56Mn by inducing thermal neutron capture. 2g sample of 55Mn is put into the reactor which has a flux of thermal neutrons of 3E13 neutrons/cm^2*s Sample is in the reactor for 8 hours and then removed. a. Calculate the amount and activity of...

Homework Statement DT fusion produces 14.1 MeV neutrons. A diagnostic for a total fusion yield is the Cu-63( n, 2n)Cu-62 reaction. A) what is the threshold for this reaction? Cu-63 also undergoes a radiative capture reaction yielding Cu-64. This reaction has a thermal cross section of 4.5b...

Neutron star is said to have masses so compact that 10 miles of it would have more mass than the sun. For example two neutron star collides, can a small fragment be separated from it forming a meteor? And if a small piece were to enter Earth atmosphere and reach land. Would the neutron star as...

Homework Statement In an experimental setup (shown in attachment) like this for neutron diffraction, how do I find the wavelength of the neutron. It should be around 2nm. Homework Equations \lambda = \frac{h}{mv}=\frac{396}{v} The Attempt at a Solution I am having trouble with...

Homework Statement In an experiment carried out with a beam of thermal neutrons it is found that on traversing a 2mm thick foil of 197Au, some 70% of the neutrons are removed. What is the total thermal neutron cross-section for this isotope of gold? (Density of gold: 19300 kg m-3) Homework...

An electron and a proton can not form a neutron because they are short about 800KeV of energy. If we place an electron 200 fermi from a proton there is a strong electrostatic attraction. As the electron moves towards the proton electrostatic potential energy is converted to kinetic energy of the...

If I have a low energy neutron and I bring it close to a nucleus it will be captured when it gets close enough. How can I calculate the shape of the potential well of the nucleus for neutron capture? I keep reading that it is due to the strong force, which I agree with. But it is some...

After a supernova what compels the left over core to be either a neutron star or a pulsar? is it decided before or after explosion? any thoughts would be appreciated.

Specifically, what happens to the identical fermions in a neutron star as the neutron star collects additional mass that makes it into a black hole. Fermions cannot occupy the same state according to the Pauli exclusion principle, what happens to them in the black hole?

Neutron stars are held together by extremely strong gravitational force. What would happen to a chunk of the star if it had been removed and left to stand alone? Same question for a chunk of a white dwarf?

I recently read an article that said that experiments in synchotrons had indicated that an electron was the most spherical object in the universe. It stated that if an electron were the same diameter as the solar system, the variation in its diameter would be less than the thickness of a human...

From https://www.physicsforums.com/showthread.php?t=40391 in gravitational time dilation. At the center of neutron star PSR J1614-2230 at 1.97 SM mass of Sun 1.9891×10^30 kg mass of PSR J1614-2230. 4 ×10^30 gravitational constant = 6.67300 × 10-11 m3 kg-1 s-2 radius(rough estimate) =...

Eur. Phys. J. C (2006) THE EUROPEAN PHYSICAL JOURNAL C Digital Object Identifier (DOI) 10.1140/epjc/s2006-02479-8 Ultra low momentum neutron catalyzed nuclear reactions on metallic hydride surfaces A. Widom 1, L. Larsen 2 1 Physics Department, Northeastern University, 110 Forsyth Street...

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...

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...