# Tag Info

6

There is a misconception in your question, specifically: how does a neutron weigh more than itself plus 2 extra particles It doesn't. A hydrogen atom is composed only of a proton and an electron, but no neutron. Hydrogen is shown diagrammatically shown below: Image Source If a neutron were included, then it becomes the isotope of hydrogen, ...

2

I'm going to make the assumption that you're asking about the "beryllium reflector" that you find surrounding reactor cores, or around neutron moderators at neutron sources. You're mistaken in your question #2. For thermal neutrons beryllium has capture cross section $\sigma_\text{capture} = 7.6\,\rm millibarn$ and scattering cross section ...

0

I imagine that the simplest experiment you could do to show the non-specialist would be measuring the pion charge ratios near the pion-production threshold on the first few light targets ($^1\mathrm{H}$, $^2\mathrm{H}$, $^3\mathrm{He}$ $^4\mathrm{He}$). That is we're looking at the reactions \begin{align} e^- + {}^Z\!A &\longrightarrow e^- + ... 0 A three-body capture, ^AZ + \mathrm{n+n} \to {}^{A+2}{Z} + \gamma  is exceedingly unlikely because it is essentially impossible for three bodies to converge at the same place. However, sequential captures \begin{align} ^AZ + \mathrm n &\to {}^{A+1}Z \\ ^{A+1}Z + \mathrm n &\to {}^{A+2}Z \\ \end{align} can happen any time the neutron flux is ...

0

Natural germanium contains about 7% Ge-76. To get to Ge-78 would require two neutron captures on the same nucleus within the 11 hour half-life of Ge-77. According to the NNDC there is not data on neutron capture cross section for Ge-77, so if you are in fact seeing two-neutron capture you are in a position to make a very interesting measurement. I would ...

1

http://www.nndc.bnl.gov/nudat2/indx_adopted.jsp Appears to be the answer I was looking for, if anyone else is interested.

0

Even if it is pure neutrons, I doubt that it can be called one single atom. Strong forces are short ranged and I don't think a macroscopic number of neutrons can form one single bound state. Instead they will form into many bound states each with a few neutrons. Calling a neutron star a giant $Z=0$ atom would be like calling the earth, which is made of ...

13

It is a misnomer (at best) to characterize a neutron star as all neutrons. There are protons and electrons too. Imagine compressing a bunch of regular matter at some point it requires less energy for a proton and electron to combine to form another neutron rather than for the electron to try to fill a very high energy state. That means there are so many ...

1

While your answer has elements of "check my work" in it, as discussed in the comments above, I think the basic questions you posed are legitimate. Yes, the question refers to the kinetic energy of the neutrons, and the de Broglie wavelength associated with them; and yes, "other energies" will appear because higher order scattering can occur between the same ...

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