PRODUCTION AND PROPERTIES OF C¹⁵

Abstract

Uniform thin C 14 targets on 2500 Å nickel backings were prepared in a discharge tube containing acetylene (enriched to 28.8% C 14 ). A NaI (Tl) crystal was used to measure the yield of C 15 (2.25 ± 0.05 sec. half life) from C 14 (d, p)C 15 from E d = 1.3 to 3.0 Mev. A 7.5 ± 1.5 sec. activity was also observed, presumably N 16 produced by C 14 (d, γ)N 16 . The C 15 gamma-ray spectrum indicates only a 5.3-Mev. transition. A plastic scintillator was used to measure the C 15 beta spectrum. End-point energies of 9.5 ± 0.3 and 4.5 ± 0.2 Mev. with a branching ratio of 4 to 1 favoring the lower energy component were observed. The results are consistent with a spin and parity assignment of 1/2(+) for the C 15 ground state.