  A new indium-loaded liquid scintillator (LS) with up to 15wt% In and high
light output promises a breakthrough in the 25y old proposal for observing pp
solar neutrinos (nue) by tagged nue capture in 115In. Intense background from
the natural beta-decay of In, the single obstacle blocking this project till
now, can be reduced by more than x100 with the new In-LS. Only non-In
background remains, dramatically relaxing design criteria. Eight tons of In
yields ~400 pp nue/y after analysis cuts. With the lowest threshold yet, Q=118
keV, In is the most sensitive detector of the pp nue spectrum, the long sought
touchstone for nue conversion.
