Constraining the Neutrino Mass Using Cyclotron Radiation Emission Spectroscopy

Abstract

The existing prototype to demonstrate the viability of the Cyclotron Radiation Emission Spectroscopy (CRES) has been upgraded to incorporate tritium compatibility. The spectrum of the conversion electrons from $^{83m}Kr$ has been measured with great linearity and a precision of $2 \ eV$ over the energy range of $17-32 \eV$. The first tritium beta-spectrum using CRES has also been measured to conclude an endpoint value of $E_0 = 18574.1 \pm (17.2)_{stat.} + \left(^{+12.5}_{-21.1}\right)_{sys.} \ eV$. The recorded tritium spectrum is analyzed to set the first CRES limit on the neutrino mass, $m_\beta \ < 146 \ eV \ \ (90\% \ C.L.)$.