Radiochemical experiments for low-energy solar-neutrino detection have been making headlines by exploiting the isotopes \iso{ Cl}{ 37} and \iso{ Ga}{ 71}. Such a very low-threshold measurement of this type can also be performed using \iso{ Tl}{ 205}, which has been considered for decades for this purpose. A unique feature of this detector nucleus is the integration is the solar-neutrino flux over millions of years owing to its long-living daughter \iso{ Pb}{ 205}. In this study we have calculated for the first time the cross section for the charged-current solar-neutrino scattering off \iso{ Tl}{ 205}. Taking into account the solar-model-predicted neutrino fluxes and the electron-neutrino survival probabilities, a solar-neutrino capture rate of 62.2 $\pm 8.6$ SNU is determined, a value significantly smaller than in previous estimates.
Categories: nucl-th hep-ph