Laboratory simulation of direct positron annihilation in a neutral hydrogen galactic environment.
01 January 1986
The linewidth for thermalized positrons directly annihilating with bound electrons in low-density molecular hydrogen gas has been found to be 1.55 +-0.09 keV, using a germanium (Ge) detector with a low-energy pulsed positron beam. This linewidth measurement together with previous experimental results makes it possible to precisely determine the composite spectrum due to positrons annihilating in a neutral hydrogen galactic medium.