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

Abstract

Background: The ¹⁷⁶Yb(n,γ)¹⁷⁷Yb→¹⁷⁷Lu reaction is of interest in nuclear medicine as it is the preferred production route for ¹⁷⁷Lu. 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 ¹⁷⁶Yb(n,γ)¹⁷⁷Yb 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 ¹⁷⁶Yb(n,γ)¹⁷⁷Yb by means of the time-of-flight technique at the Experimental Area 1 of the n_TOF facility at CERN using an enriched ¹⁷⁶Yb₂O₃ 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 ¹⁷⁶Yb(n,γ)¹⁷⁷Yb 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.