DELAYED PROTONS FOLLOWING ²¹Mg AND ²⁵Si DECAY

Abstract

The delayed-proton precursors 21 Mg and 25 Si have been produced by proton bombardment of targets of sodium, magnesium, aluminum, and silicon dioxide in the internal beam of the McGill synchrocyclotron. Half-lives of 118 ± 4 and 225 ± 6 msec respectively were measured, and a spin-parity assignment of (5/2) + has been made to the ground state of 21 Mg. Strong lines in the delayed-proton spectra have been attributed to decay of the expected first T = 3/2 states in 21 Na and 25 Al, fed by superallowed β transitions from the respective precursors 21 Mg and 25 Si.