Determination of γ-ray branching ratios for ⁹⁵Zr and ¹⁴⁷Nd

Technical Report · Mon Jun 08 04:00:00 EDT 2020

DOI:https://doi.org/10.2172/1633525· OSTI ID:1633525

Kolos, K. ^[1]; Scielzo, N. D. ^[1]

---

1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

For many fission products, the γ rays emitted following decay provide an easily-detectable signature that can be used to identify their quantities and distributions in a sample. As a result, γ-ray spectroscopy is often exploited to study fission-product yields (FPYs), provided sufficiently accurate information on the γ-ray branching ratio is available. However, in many cases, the uncertainties in the existing nuclear data are large enough that they compromise the precision achievable for modern experiments and applications. To address this need, we have developed a new experimental method that is well suited to precisely measure the γ-ray branching ratios in the decay of long-lived fission products. The approach involves the production of a radiopure sample by implantation of a mass-separated ion beam from the CAlifornium Rare Isotope Breeder Upgrade (CARIBU) facility on a thin carbon foil. The emitted β -decay radiation is detected with a 4π gas proportional counter and a meticulously efficiency-calibrated high-purity germanium (HPGe) detector. As a first measurement to demonstrate the approach, we studied the γ-ray branching ratios of the strongest transitions following the decay of ⁹⁵Zr and decay-daughter ⁹⁵Nb and determined these branching ratios to fractional precisions of 1%. We then applied this approach to determine the γ-ray branching ratios for the β decay of ¹⁴⁷Nd. The results for the γ-ray branching ratios are presented here and compared to previous results and evaluations.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Argonne National Laboratory (ANL), Argonne, IL (United States); Texas A & M Univ., College Station, TX (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• DOE Contract Number: AC52-07NA27344; AC02-06CH11357; FG03-93ER40773
• OSTI ID: 1633525
• Report Number(s): LLNL-TR--811617; 1018237
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
73 NUCLEAR PHYSICS AND RADIATION PHYSICS