Szintillationseigenschaften von Anthracen- und Naphthalinkristallen beim Beschuß mit energiereichen α-Teilchen, Deuteronen und Elektronen bei tiefen Temperaturen*

Abstract

The scintillation response of anthracene crystals has been investigated with 7.0 MeV a particles within the temperature range 1.5°K < T < 300°K and with 46 MeV α particles and 24 MeV deuterons within the temperature range 11°K < T < 300°K. With decreasing crystal temperature the scintillation light yield increases towards a temperature independent but still angularly dependent limiting value reached at about 4 CK. The angular dependence of the scintillation light yield shows a so far unknown sharp peak at particle impact directions nearly paralel to the (a, b) plane. The peak changes with crystal temperature and ionization density in a complicated manner and disappears below 10°K. For 0.6 MeV β particles the scintillation light yield has been investigated within the temperature range 11°K < T < 300°K. It increases with decreasing temperature less steeply than the α-light yield, i. e. the α/β yield ratio increases as the crystal temperature decreases. From this it is concluded that the quenching of excitations within an ionization column is a function of the crystal temperature. Similar results have been obtained with single crystals of naphthalene. A possible relation between the scintillation anisotropy and the anisotropy of the lattice thermal conductivity has been examined.