A possible gas for solar neutrino spectroscopy

We discuss the possibility of using pure CF₄ to fill a 2000 m³ Time Projection Chamber in order to detect the solar neutrinos through the elastic scattering v_ee^? → v_ee^?, with the threshold of 100 keV on the kinetic energy of the recoiling electron. In a volume of 2000 m³ of CF₄ at normal pressure and room temperature, which corresponds to a mass of 7.4 ton, we expect ~ 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, ⁷Be, and, eventually, ⁸B. We find that ¹⁴C is a possible severe source of background: it is necessary to have a ratio ¹⁴C/¹²C lower than 10^?19 in order to be able to identify the pp neutrinos.