“…More details about instrumental and experimental parameters can be found in Zhang et al (2021). 53 The results for 202 Hg, 204 (Pb + Hg), 206 Pb, 207 Pb, 208 Pb, 232 Th, and 238 U were acquired simultaneously on different detector configurations: 202 Hg on IC4, 204 (Pb + Hg) on IC5, 206 Pb on IC2, 207 Pb on IC1B, 208 Pb on IC6, 232 Th on H3, and 238 U on H4. The integration time was set at up to 0.131 s. Instrument tuning was carried out on an NIST SRM 614 with a laser repetition of 6 Hz, energy density of 3 J cm −2 , and diameter of 75 μm to ensure 238 U signal intensities > 12 mv (750 000 cps).…”