[en] Neutrino-electron scattering can be used to probe neutrino electromagnetic properties at low-threshold underground detectors with good recoil electron energy resolution. We study the sensitivity of Helium detector experiments, such as HELLAZ, for artificial anti-neutrino sources. We show that, for a ⁹⁰Sr -- Y source, one expects a sensitivity to the neutrino magnetic moment at the level of μ_ν = 2 x 10^-11 μ_B. We also report the sensitivity that these experiments could have in searching for an additional gauge boson in E₆ models