Decay of Short-Lived Barium and Lanthanum Fission Products

The half-lives and gamma-ray spectra of the short-lived barium and lanthanum fission products have been measured. ${\mathrm{Ba}}^{141}$ has a half-life of 18±1 min and emits x-rays and gamma rays of 120 kev, 190 kev, 290 kev, ∼350 kev, 460 kev, 640 kev, and 740 kev. ${\mathrm{Ba}}^{142}$ has a half-life of 11±1 min and emits x-rays and gamma rays of 80 kev, ∼260 kev, 890 kev, 970 kev, 1080 kev, 1200 kev, 1360 kev, and 1680 kev. ${\mathrm{La}}^{141}$ has a half-life of 3.85±0.10 hr and emits a low intensity gamma ray at 1370 kev. ${\mathrm{La}}^{142}$ has a half-life of 85±6 min and emits gamma rays of 640, 900, 1030, 1080, 1370, 1540, 1750, 1920, 2080, 2400, 2570, 3000, 3300, and 3650 kev.