A possible gas for solar neutrino spectroscopy

We discuss the possibility of using pure CF4 to fill a 2000 m(3) Time Projection Chamber in order to detect the solar neutrinos through the elastic scattering nu(e) + e(-) --> nu(e) + e(-), with the threshold of 100 keV on the kinetic energy of the recoiling electron. In a volume of 2000 m(3) of CF4 at normal pressure and room temperature, which corresponds to a mass of 7.4 ton, we expect similar to 3300 of such events per year. The detector can give the spectrum of the low energy neutrinos from the Sun and it can identify solar neutrinos of different origin: pp, Be-7, and, eventually, B-8. We find that C-14 is a possible severe source of background: it is necessary to have a ratio C-14/C-12 lower than 10(-19) in order to be able to identify the pp neutrinos.