Measurement of the Yb 176 (n,γ) cross section at the n_TOF facility at CERN

Background: The Yb176(n,γ)Yb177→Lu177 reaction is of interest in nuclear medicine as it is the preferred production route for Lu177. This radioisotope has seen a very fast growth of usage in nuclear medicine in recent years due to its outstanding properties. New data on this reaction could provide useful information for production at new facilities. Purpose: We aim to resolve resonances in the Yb176(n,γ)Yb177 reaction for the first time. Previous capture measurement provided data at thermal point and encompassed integral measurements in the range from 3 keV to 1 MeV, where three time-of-flight measurements are available, but with low resolution to resolve the resonances. Transmission measurements from the 1970s resolved and analyzed some resonances. Method: We measure the neutron capture cross section of Yb176(n,γ)Yb177 by means of the time-of-flight technique at the Experimental Area 1 of the n_TOF facility at CERN using an enriched Yb1762O3 sample and an array of four C6D6 liquid scintillation detectors. Results: We have resolved 164 resonances up to 21 keV, including 96 new ones. We also provide new capture experimental data from 90 eV to 3 keV, and we extend the resolved resonance region up to 21 keV. In addition, resonance decay widths, Γγ and Γn, are provided for all resonances together with resonance energies. Conclusions: The Yb176(n,γ)Yb177 reaction has been measured, providing resonance parameters for the first time from a few eV to 21 keV. The analysis of the resonances has been carried out and compared with previous works and existing libraries, revealing discrepancies due to the new information on Γγ parameters. Our results are consistent with the Γn parameters obtained in transmission measurements.