Engineering360: "What are Armchair Graphene Nanoribbons?"

Interesting graphic about the properties and potentiality of uses in electronics.

It is also known that GPO (or GO?) graphene oxide is a nearly perfect proton conduit when this material is in contact with water solutions. Question is this: If a proton enters a graphitic structure as a result of diffusion or charge induced transport through the defect opening of GPO, how hard would it be (not hard at all IMHO) for the proton to become immobilized between sheets of graphene, and held there in the lattice interstitial space, almost as if there were a nano-scale pair of tweezers, so tightly that the Heisenberg uncertainty in momentum becomes wildly large. Large enough to allow capture of an electron from the SPP cloud of graphite? I am referring to nuclear capture, not electronic capture.

It would probably be easiet to start with He3 with the aim of converting to H3.

Are you sure that is energetically favorable? I don't happen to have any ³He in my pocket, anyway.

Relatively more favorable than going from 1H to n.

Consider the half lives of a thermal neutron as compared to 3He. Minutes compared to years.

At the heart of the Heisenberg trap, is the idea that the trapped entity may only acquire sufficient energy to undergo the reaction with the electron (¹H+e^- → n(cold)), the nascent neutron is considered to be at 0 °K at the instant it is formed.

Granted that thermalization of said neutron would be fairly rapid in condensed media (I think we are talking 500 femtoseconds to 1 nanosecond), however one also has to consider the absorption cross-section for cold neutrons is usually >1000X that for a thermal one (for the same target isotope as the absorber). For example ²³⁵U has a thermal neutron σ of some 200-300 barns, but the cold neutron σ is ~10⁶ barns.

I should normally expect more ¹³C as ²H (or ³H or the mysterious ⁴H→⁴He+β^-), since the greater number of near neighbors might easily be carbon rather than protons, or water molecules. The only thing going for absorption of the cold neutron by proton is the idea that the cold neutron would begin to thermalize and move out of location very quickly, and might have a probability of "seeing" a nearby trapped proton in the interstices between sheets of graphene.

I really don't know anything about cold neutrons.

Anything you would suggest I read?

https://en.wikipedia.org/wiki/Neutron_temperature

Of note are several classifications. Do you agree that for Cadmium to act as a neutron absorber, the neutrons have to be above "thermal" kinetic energy?

Instead of "cold" neutrons, I should have referred to my supposed nascent neutrons as UCN (ultra-cold neutrons). These can be held in traps for some amount of time.

https://en.wikipedia.org/wiki/Ultracold_neutrons

Information about UCN (ultra-cold neutrons).

https://arxiv.org/pdf/1207.5887.pdf

Paper on the determination of the asymmetry parameter A (apparently has to do with calculation of theoretical lifetime of UCN.

I think what I have been leaving out of any supposed or pre-supposed hypothesis about UCN formation from Heisenberg trapped protons (with energy arriving from SPP electron cloud of graphene) is the necessary extra mass of the neutrino (or exceedingly high SPP energy contribution). I believe now the limiting factor might well be the neutrino flux density, along with the neutrino cross-section for a cold proton, which might be practically nearly vanishing. Typically neutrino experiments are known for exceedingly large tanks of water lined with event detectors.

Thank you.

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No, I would not agree that for cadmium to act as a poison the neutrons need to have greater than thermal energy.

Explain, please, in terms of the energy thresholds listed, as I apparently also failed to grasp that.

Cadmium is a strong absorber of neutrons in the thermal and epithermal regions. It is used as a burnable poison, an emergency shutdown poison, and in control rods for this very reason.

Most isotopes of cadmium have cross section for absorption that is roughly inversely proportional to neutron velocity, except through the epithermal region, in which resonances an create peaks with very large cross sections. By the time neutrons are above epithermal, the resonances are gone and the absorption, still roughly following the inverse of velocity is pretty low.

There is one standout isotope is Cd-113. It makes up 12+% of natural cadmium, yet it dominates neutron absorption as its cross sections are much higher especially in the thermal range...and also with much less adherence to the inverse velocity proportionality.

Thank you for the teaching lesson, and it was well explained, so even I could understand it.