Decay of Cl39
Abstract
The beta- and gamma-ray spectra of 55-minute Cl39 were studied by means of magnetic and scintillation spectrometers. A first forbidden unique (ΔI=2, yes) beta transition takes place to the ground state of A39 in 7+/-2% of all decays with an end-point energy of 3.45+/-0.02 Mev and a ft value of 7.8 (f1t=8.3). Beta transitions to the second excited level of A39 at 1.52 Mev take place in 85+/-6% of the transitions and have an end-point energy of 1.91+/-0.02 Mev (ft=5.57). The remaining 8+/-4% of the beta transitions take place to the first excited level at 1.266 Mev (ft=6.8). Three gamma rays were found with energies of 0.246+/-0.003, 1.266+/-0.010, and 1.520+/-0.010 Mev, and relative intensities of 0.9+/-0.1, 1, and 0.85+/-0.05, respectively. The 0.240- and 1.266-Mev gamma rays are in cascade. Each of the three gamma rays is in coincidence with beta rays with end-point energies of 1.90+/-0.05 Mev. A beta-gamma delay is observed with a half-life of (0.95+/-0.05)×10-9 second. The metastable level is shown to be the second excited state. A decay scheme based on these data is proposed.
- Publication:
-
Physical Review
- Pub Date:
- November 1956
- DOI:
- 10.1103/PhysRev.104.740
- Bibcode:
- 1956PhRv..104..740P