Spontaneous fission of light californium isotopes produced in 206,207,208Pb + 34,36S reactions; new nuclide 238Cf
Abstract
In bombardments of 206,207,208Pb with 34S and 206Pb with 36S, we identified a new spontaneously fissioning isotope 238Cf with T sf ≈ T {1}/{2} = 21 ± 2 ms and obtained evidence of the production of a new isotope 237Cf with T {1}/{2} = 2.1 ± 0.3 s. The spontaneous-fission (SF) decay mode was established for 240Cf; its SF branch was estimated to be bsf ∼ 2 × 10 -2. We measured also bsf ⩽ 1.4 × 10 -4 for 242Cf and estimated bsf ∼ 10 -1 for 237Cf. The production cross sections of 238Cf in the 206,207,208Pb + 34S reactions were measured to be in the range of 0.3 to 1.1 nb. Finally, we probed the influence of the neutron excess in the N = 20 projectile 36S on cross sections of fusion-evaporation reactions occurring on lead targets.
- Publication:
-
Nuclear Physics A
- Pub Date:
- February 1995
- DOI:
- 10.1016/0375-9474(95)00002-I
- Bibcode:
- 1995NuPhA.588..501L
- Keywords:
-
- RADIOACTIVITY 237;
- 238;
- 240CF (SF);
- MEASURED T1/(2);
- DEDUCED SPONTANEOUS FISSION BRANCHES;
- 242CF (SF);
- MEASURED UPPER LIMIT FOR SPONTANEOUS-FISSION BRANCH;
- 246FM;
- MEASUREDT1/(2);
- NUCLEAR REACTIONS 206;
- 207;
- 208PB(34S;
- X);
- 206PB(36S;
- E = 215 MEV;
- 208PB(40AR;
- E = 225 MEV;
- MEASURED PRODUCTION σ FOR SPONTANEOUSLY FISSIONING237;
- 240 CF NUCLEI;
- ISOTOPICALLY ENRICHED TARGETS