Measurements of anisotropic scintillation efficiency for carbon recoils in a stilbene crystal for dark matter detection

AbstractIt is known that scintillation efficiency of organic single crystals depends on the direction of nuclear recoils relative to crystallographic axes. This property could be applied to the directional WIMP dark matter detector.The scintillation efficiency of carbon recoils in a stilbene crystal was measured for recoil energies of 30 keV to 1 MeV using neutrons from 7Li(p,n)7Be and 252Cf. Anisotropic response was confirmed in low energy regions. The variation of the scintillation efficiency was about 7%, that could detect the possible dark matter signal