A COMPARISON OF THE X-RAY PERFORMANCE OF TlBr CRYSTALS GROWN BY THE BRIDGEMAN-STOCKBARGER AND TRAVELLING MOLTEN ZONE METHODS V. Gostilo 1, A. Owens 2, M. Bavdaz 2, I. Lisjutin 1, A. Peacock 2, H. Sipila 3, S. Zatoloka 1 1 Baltic Scientific Instruments Ganibu dambis 26, P. O. Box 33, LV-1005, Riga, Latvia 2 Astrophysics Division ESA/ESTEC Postbus 299, 2200AG Noordwijk, The Netherlands 3 Metorex Int. Oy P.O.Box 85, FIN-02631, Espoo, Finland

T l B r Bandgap – 2,678 eV Atomic number – Tl-81, Br-35 Density –7.5 g/cm 3 Traveling Molten Zone method Bridgeman-Stockbarger method Energy, keV Single detector Pixel detector keV1.0 keV keV2.2 keV keV3.7 keV keV

TABLE 1 TABLE 1 The electrical and transport characteristics of the crystals grown by the two methods

Spectrum of the source Am-241, registered by the detector J2 at a temperature –15°С and a bias of +500V. Spectrum of the source Am-241, registered by the detector J2 at a temperature –15°С and a bias of -500V. 2.5 keV 1.14 keV 1.37 keV 7.89 keV

Spectrum of the source Cd-109, registered by the detector J2 at a temperature –15°С and a bias of +500V. 3.3 keV

Spectrum of the source Co-57, registered by the detector J2 at temperature –15°С and a bias of +500V. 4.4 keV

Spectrum of the source Cs-137, registered by the detector J2 at temperature –15°С and a bias of +50V keV

TABLE 2 TABLE 2 The best resolution values (in keV) obtained at various energies

CONCLUSIONS 1.Spectroscopic performance for detector crystals growth by both methods is compatible. 2.Further improvement of growth technology is required. 3.Efforts should be aimed at the improvement of transport characteristics. 4.The nature of carrier trapping should be clarify. Acknowledgments The authors thank Dr. K. Hitomi (Tohoku Institute of Technology, Japan) for providing crystals for test and evaluation and for valuable discussions.