Positron-electron annihilation momentum transfer to trapped deuterons

The probability of positron annihilation momentum transfer to a trapped deuteron is calculated based on neutron measurements from 2H(d,n)3He reactions in deuterated palladium thin films. Deuterium gas loading in Pd thin films creates a high D/Pd fraction at point defects in the metal lattice. Unmoderated positrons from a Na-22 source thermalize and are trapped in the same point defects as deuterium in the Pd thin films. Similar to the Mössbauer effect, an interaction with the surrounding crystal lattice allows for conservation of momentum during electron-positron annihilation energy transfer to the trapped deuteron.