A technique to measure the neutron lifetime from low-earth orbit

Abstract

A new technique to measure the mean life of the neutron to beta decay, τ_n, is described. It uses the fact that neutrons created in the atmosphere with energies below 0.65 eV are gravitationally bound. Consequently, in the absence of beta decay, upward- and downward-going neutron currents above the atmosphere would be equal. The actual ratio of these currents therefore provides a sensitive measure of τ_n. An estimate of up-down countrates, of all known backgrounds, and of systematic uncertainties for a conceptual experiment indicates that an accuracy on τ_n of better than 1% could be achieved using a properly designed sensor in low-Earth orbit.