Operation of an Archaeological Lead PbWO4 Crystal to Search for Neutrinos from Astrophysical Sources with a Transition Edge Sensor

The experimental detection of the CE ν NS allows the investigation of neutrinos and neutrino sources with all-flavor sensitivity. Given its large content in neutrons and stability, Pb is a very appealing choice as target element. The presence of the radioisotope 210 Pb (T 1 / 2 ∼ 22 yrs) makes natural Pb unsuitable for low-background, low-energy event searches. This limitation can be overcome employing Pb of archaeological origin, where several half-lives of 210 Pb have gone by. We present results of a cryogenic measurement of a 15 g PbWO 4 crystal, grown with archaeological Pb (older than ∼ 2000 yrs) that achieved a sub-keV nuclear recoil detection threshold. A ton-scale experiment employing such material, with a detection threshold for nuclear recoils of just 1 keV would probe the entire Milky Way for SuperNovae, with equal sensitivity for all neutrino flavors, allowing the study of the core of such exceptional events.