T l B r

V.Gostilo1, A.Owens2, M.Bavdaz2,I. Lisjutin1, A.Peacock2, H.Sipila3, S.Zatoloka1 1Baltic Scientific InstrumentsGanibu dambis 26, P.O.Box 33, LV-1005,Riga,Latvia 2Astrophysics DivisionESA/ESTEC Postbus 299, 2200AG Noordwijk, The Netherlands 3Metorex Int.OyP.O.Box 85, FIN-02631, Espoo, Finland A COMPARISON OF THE X-RAY PERFORMANCEOF TlBr CRYSTALS GROWN BY THE BRIDGEMAN-STOCKBARGER ANDTRAVELLING MOLTEN ZONE METHODS

T l B r Bandgap – 2,678 eV Atomic number – Tl-81, Br-35 Density –7.5 g/cm3 Bridgeman-Stockbarger method Traveling Molten Zone method

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

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

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

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

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

CONCLUSIONS • Spectroscopic performance for detector crystals growth by both methods is compatible. • Further improvement of growth technology is required. • Efforts should be aimed at the improvement of transport characteristics. • 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.

T l B r

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