  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
$^{90}Sr-Y$ source, one expects a sensitivity to the neutrino magnetic moment
at the level of $\mu_{\nu}= 2 \times 10^{-11}\mu_{B}$. We also report the
sensitivity that these experiments could have in searching for an additional
gauge boson in $E_6$ models.
