As the star collapses, the Fermi energy of the electrons increases to the point where it is energetically favorable for them to combine with protons to produce neutrons ( via inverse beta decay, also termed electron capture and " neutronization " ).
12.
TNU is specific to the inverse beta decay detection mechanism with protons . 1 TNU corresponds to 1 geoneutrino event recorded over a year-long fully efficient exposure of 10 32 free protons, which is approximately the number of free protons in a 1 kiloton liquid scintillation detector.
