  We investigate the spin-to-charge conversion emerging from a mesoscopic
device connected to multiple terminals. We obtain analytical expressions to the
characteristic coefficient of spin-to-charge conversion which are applied in
two kinds of ballistic chaotic quantum dots at low temperature. We perform
analytical diagrammatic calculations in the universal regime for
two-dimensional electron gas and single-layer graphene with strong spin-orbit
interaction in the universal regime. Furthermore, our analytical results are
confirmed by numerical simulations. Finally, we connect our analytical finds to
recent experimental measures giving a conceptual explanation about the apparent
discrepancies between them.
