Production cross section measurements of radioactive isotopes by BigRIPS separator at RIKEN RI Beam Factory

We have measured the production rates and production cross sections for a variety of radioactive isotopes which were produced from ¹²⁴Xe, ⁴⁸Ca, and ²³⁸U beams at an energy of 345 MeV/nucleon using the BigRIPS separator at the RIKEN Nishina Center RI Beam Factory (RIBF). Proton-rich isotopes with atomic numbers Z = 40-52 and neutron-rich isotopes with Z = 5-16 were produced by projectile fragmentation of the ¹²⁴Xe and ⁴⁸Ca beam on Be targets, respectively. Neutron-rich isotopes with Z = 20-59 were produced by in-flight fission of the ²³⁸U beam, in which both Be and Pb were used as production targets. The measured production rates and production cross sections were compared with those of the LISE ⁺⁺ calculations, and overall fairly good agreement has been obtained. Furthermore, in the measurements with the ¹²⁴Xe beam, we have discovered four new isotopes on the proton-drip line, ^85,86Ru and ^81,82Mo, and obtained the clear evidence that ¹⁰³Sb is particle unbound with an upper limit of 49 ns for the half-life. The measurements of projectile-fragment momentum distributions have been also performed with the ¹²⁴Xe beam, in which the low-momentum tails of the distributions have been measured for the first time at the energy of 345 MeV/nucleon.