Plutonium-241 as a possible isotope for neutrino mass measurement and capture

Abstract

Abstract Tritium has been the isotope of choice for measurements of the absolute neutrino mass and planned detection of the relic neutrino background. The low mass of 3H leads to large recoil energy of the nucleus. This has emerged as a limiting factor in both measurements. We investigate 241Pu as an alternative. The recoil is 80 times smaller and it has similar decay energy and a lifetime to 3H. We evaluate for the first time its soft-neutrino capture cross-section and find (σ v) ν = 1.52 × 10−45 cm2. This is 40% of the capture cross-section for tritium, making 241Pu an interesting alternative for 3H.