Effect of source preparation technique on the differential angular correlation of the 133–482 keV cascade in 181Ta

Abstract

By using a standardised method of source preparation and an ultra-fast coincidence circuit the differential angular correlation of the 133–482 keV cascade in 181Ta using sources of Hf(OH) 4 in HF, HClO 4, HCl, HNO 3, H 2SO 4, and CH 3COOH medium has been measured. The results are (1) no attenuation in HF, (2) λ 2=(4.0±0.3) × 10 7 s −1, λ 4=(6.6±2.8) × 10 7 s −1 in HClO 4, (3) λ 2=(7.8±0.3) × 10 7 s −1, λ 4(13.0±1.8) × 10 7 s −1 in HCl,(4) λ 2=(9.5±0.5) × 10 7 s −1, λ 4=(11.4±3.9) × 10 7 s −1 in HNO 3, (5) λ 2=(26.1±0.2) × 10 7 s −1 in H 2SO 4, and (6) a two-exponential decay in CH 3COOH medium with λ 1 2=(4.1±0.2) × × 10 8 s −1 and λ 2 2=(0.14±0.02) × 10 8 s −1. The experiments in HClO 4 and HNO 3 medium are new. The other results are compared with the nature and magnitude of the results obtained by other workers in terms of the chemistry of Hf-ions in solution.