Majority carrier traps produced in arsenic‐doped silicon by 1.5‐MeV electron irradiation are characterized by deep level transient spectroscopy. Four traps are observed including a new defect located atEc−0.30 eV. It is also observed that oxygen plays a vital role in the annealing mechanism of the arsenic‐vacancy pair. This defect, with a level atEc−0.42 eV, has two annealing stages, the first being much faster than the second. Its first annealing stage cannot be explained by another defect superimposed upon the As‐Vpair.