Geochemical constraints on the half-life of 130Te

To determine the half-life of Te-130 we have analyzed multiple aliquots of geological telluride samples 100 times smaller than those previously reported using a unique resonance ionization mass spectrometer. We employ a low-fluence neutron irradiation that allows determination of parent and daughter from the same xenon isotopic analysis. Step heating of these irradiated samples allows the Xe-130/Xe-132 ratio of fluids trapped inside the tellurides to be determined. Considering only samples where the trapped Xe-130/Xe-132 ratio is demonstrably consistent with atmospheric xenon, we can avoid over- or under-estimating the half-life due to redistribution or inheritance of radiogenic Xe-130. Combining our work with literature data, it is clear that several relatively young samples have retained xenon quantitatively since formation, allowing the half-life to be determined as (8.0 +/- 1.1)x10(20) yr. Older samples have clearly been affected by post-formation processing. This suggests that there is little hope of monitoring solar luminosity through the geological record of Xe-126 production by solar neutrinos, but it is possible that geologically useful chronological information can be obtained from this system.