  We present ultra low energy results taken with the novel Spherical
Proportional Counter. The energy threshold has been pushed down to about 25 eV
and single electrons are clearly collected and detected. To reach such
performance low energy calibration systems have been successfully developed: -
A pulsed UV lamp extracting photoelectrons from the inner surface of the
detector - Various radioactive sources allowing low energy peaks through
fluorescence processes. The bench mark result is the observation of a well
resolved peak at 270 eV due to carbon fluorescence which is unique performance
for such large-massive detector. It opens a new window in dark matter and low
energy neutrino search and may allow detection of neutrinos from a nuclear
reactor or from supernova via neutrino-nucleus elastic scattering
