1. 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

2. 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 5.90.5 keV1.0 keV 59.62.7 keV2.2 keV 1224.4 keV3.7 keV 66229.0 keV

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

4. 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

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

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

7. Spectrum of the source Cs-137, registered by the detector J2 at temperature –15°С and a bias of +50V. 27.7 keV

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

9. 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.