End-point energy and half-life of the Re-187 beta decay - art. no. 014302

A high statistics measurement of the beta decay of Re-187 with a cryogenic microcalorimeter has been performed. The high accuracy and the calorimetric nature of the measurement allow setting a value for the end-point energy o f the decay in a metallic rhenium crystal equal to [2470+/-1(stat)+/- 4(sys t)] eV. A good extrapolation of the spectrum to zero energy has also been p ossible thanks to the stable and well determined detector response down to the energy threshold of about 420 eV. This allows an estimate of the Re-187 half-life of [4.12+/-0.02(stat) +/- 0.11(syst)] x 10(10) yr. Both results are significantly better than the previous measurements reported in the lit erature.