DELAYED PROTONS FOLLOWING 21Mg AND 25Si DECAY

Abstract

The delayed-proton precursors ²¹Mg and ²⁵Si 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 ²¹Mg. Strong lines in the delayed-proton spectra have been attributed to decay of the expected first T = 3/2 states in ²¹Na and ²⁵Al, fed by superallowed β transitions from the respective precursors ²¹Mg and ²⁵Si.