Aqueous harvesting of 88Zr at a radioactive-ion-beam facility for cross-section measurements

Isotope harvesting is a method of collecting the long-lived radioisotopes that build up during the operation of ion-beam facilities in a way that is useful for subsequent research. As a demonstration of this method for the collection of a group IV metal at a fragmentation facility, the high-energy Zr-88 secondary beam produced from a 140-MeV/u Mo-92 primary beam at the National Superconducting Cyclotron Laboratory (NSCL) was stopped in a water target. The setup aimed to mimic the aqueous beam dump that will be implemented at the Facility for Rare Isotope Beams (FRIB). The collected Zr-88 and accompanying Y-88 decay daughter were radiochemically extracted from the solution and made into target samples suitable for neutron-capture cross-section measurements. These samples were then irradiated at two reactor facilities, and the Zr-88 average thermalneutron-capture cross section (sigma(T)) and resonance integral (I) were determined to be sigma(T) = (8.04 +/- 0.63) x 10(5) b and I = (2.53 +/- 0.28) x 10(6) b. The sigma(T) value agrees well with previous results and I, determined for the first time here, was found to be the largest measured resonance integral by two orders of magnitude. The Y-88 thermal-neutron-capture cross section was determined to be less than 1.8 x 10(4) b. This work demonstrates the steps needed to make cross-section measurements with samples produced via aqueous isotope harvesting.

Automated summary

Isotope harvesting is a method to collect long-lived radioisotopes for subsequent research. The study demonstrated the process of collecting Zr-88 and Y-88 from a water target and using them for neutron-capture cross-section measurements. The results showed good agreement with previous findings and revealed the largest resonance integral measured for Zr-88.