Pairs of particles with opposite spins are attracted and the repulsive force from the charge is negated. Cooper pairs of protons and paired electrons in a atom are examples. How does the tunneling involving cross sections for two free nuclei-Li-6 and Li-7 consider the spin attraction of particles with opposite spins? And how would such a cross section change in a magnetic field that might align or anti-align particle spin vectors? What is the cross section if the Li-6 and Li-7 exist in a single coherent system---a nickel cyrstal lattice for example?
Bob Cook From: [email protected] Date: Wed, 9 Sep 2015 08:24:27 -0 To: [email protected] Subject: [Vo]:time, separation and neutron tunneling cross section Hi, This question is for Robin or anyone else who might know. Suppose you know that the cross section for a neutron to tunnel from 7Li to 61Ni is 1 barn at 10 MeV. Now simplify the problem to that of holding the 7Li stationary for a duration of time near the 61Ni so that the cross section remains 1 barn, after which you take the 7Li away. Given the separation distance and time that were needed to achieve this (perhaps the separation distance would be very close to the distance that the 10 MeV brought the 7Li in the original problem statement), is there a way to determine how long it would be necessary to hold the 7Li at twice a distance from the nucleus and still have a neutron tunneling cross section of 1 barn? Eric
