Measurement of the scintillation light quenching at room temperature of sodium recoils in NaI(Tl) and hydrogen recoils in NE 213 by the scattering of neutrons

At the newly installed neutron scattering facility for the calibration of Dark Matter (DM) detectors we have measured quenching factors (QFs) at room temperature in NE 213 and NaI(Tl). For proton energies E p between 1 and 3.5 MeV we found the electron-equivalent energy E ee to obey the relation E ee = ( 0.23 ± 0.03 ) E p + ( 0.02 ± 0.01 ) E p 2 . The QF of the light output from Na recoils in NaI(Tl) at 850 keV was measured to be Q = 0.21 ± 0.04 .