Gravitational Clustering of Relic Neutrinos Jc a P 12 ( 2004 ) 005

Possible ways of detecting the cosmic neutrino background are described and their difficulties discussed. Among them, the capture on the radioactive tritium nuclei is challenging, but perhaps doable. The principal difficulty is the need for the combination of a very strong source and very good detector resolution. It is argued that if it turns out that the neutrino masses follow the degenerate scenario, i.e. if mν ≥ 0.1 eV for all three massive neutrinos, then it is important to devote a substantial effort to develop a realistic detection experiment.