Author/Authors :
Onken, Drew R. Lawrence Berkeley National Laboratory, Berkeley, USA , Perrodin, Didier Lawrence Berkeley National Laboratory, Berkeley, USA , Vogel, Sven C. Los Alamos National Laboratory, Los Alamos, USA , Bourret, Edith D. Lawrence Berkeley National Laboratory, Berkeley, USA , Moretti, Federico Lawrence Berkeley National Laboratory, Berkeley, USA
Abstract :
The title compound, thallium magnesium trichloride, has been identified as a scintillator with both moderate gamma-stopping power and moderate light yield. Knowledge of its crystal structure is needed for further development. This work determines the crystal structure of TlMgCl3 to be hexagonal P63/mmc (No. 194) and isostructural with RbMgCl3, contrary to previously reported data. This structure was obtained by single-crystal X-ray diffraction and was further confirmed by neutron diffraction measurements. Extending neutron diffraction measurements to high temperature, the data show that TlMgCl3 maintains this crystal structure from 290 K up through 725 K, approaching the melting point of 770 K. Anisotropic thermal expansion coefficients increase over this temperature range, from 31 to 38 × 10−6 K−1 along the a axis and from 19 to 34 × 10−6 K−1 along the c axis.
Keywords :
TlMgCl3 , scintillator , crystal structure , high-temperature neutron diffraction
