Quenching factors for Na recoils as a function of Tl dopant concentrations in NaI(Tl) crystals. - Angloher, G.; Bharadwaj, M. R.; Böhmer, A.; Cababie, M.; Colantoni, I.; Dafinei, I.; Marco, N. Di; Dittmar, C.; Einfalt, L.; Ferella, F.; Ferroni, F.; Fichtinger, S.; et al. (European Physical Journal C -- Particles & Fields, 2026)