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Characterization of CsI:Tl recrystalization after liquid phase deposition. Ulrik Lund Olsen, Ph.D. student supervisors: H.F. Poulsen, S. Schmidt. SCINT’07, Salem Winston, June 4-8 2007. X-rays 50keV. photons 540nm. Diffracted Beam. Aims of project.
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Characterization of CsI:Tl recrystalization after liquid phase deposition Ulrik Lund Olsen, Ph.D. student supervisors: H.F. Poulsen, S. Schmidt SCINT’07, Salem Winston, June 4-8 2007
X-rays 50keV photons 540nm Diffracted Beam Aims of project Submicron grains structure resolved at high energy (30-100keV) at fast kinetic low flux diffraction meassurements. CCD Microscope Lens Grain in Aluminum Sample Mirror Scintillator fundamental relationship between scintillator thickness and resolution
Principle - Structured Scintillator CsI:Tl SiO2 Si
+ + + e- e- e- Electrochemical etching HF HF solution etches surfaces with positive donors Light induced donors are guided by an applied electric field Field determined by silicon resistivity and bias R.L. Smith and J.D. Collins, J. Appl. Phys. 71, 8, R1 (1992)
Pore Structure SiO2 1µm 10µm
Pore Filling Process • CsI:Tl powder on Silicon surface • Sealed sample holder • Tube furnace • Controlled cooling rate
Bulk characterization • Focused Ion Beam(FIB) milling 4µm Ions 10µm
Crystal characterization - EBSD Electron Backscatter Diffraction Grain size Distribution
Kβ1 Au Kα1 Kα2 Sn Kβ1 Kα1 Compositional characterization - Fluorescence Flourescence exited with 90keV synchrotron radiation: • local (w/ focused beam) • large lead(Pb) background fit
Compositional characterization - PIXE • Particle induced X-ray Emission: • 40keV protons • bulk information (250µm penetration) • global probe (2mm2 beam)
Compositional characterization - PIXE manufacturers specs on as-received was 0.2 wt% (GB crystals)
Composition characterization - SIMS Secondary Ion Mass Spectroscopy: • local information • surface probing • high compositional sensitivity (>ppm) • uneven sensitivity to different species No. Ion CentMass CI 1 I 126.8895 434 2 Cs 132.8742 564067 3 ^203Tl 203.0080 1069 4 Tl 205.0127 1362 5 Cs_2 265.7874 170843
Conclusion • Multiple characterization tools needed • textural information from high resolution EBSD • absolute composition from PIXE • meso-scale relative composition from x-ray induced fluorescence • local composition – SIMS T. Martin (ESRF) V. Honkimaki (ESRF) M. di Michiel (ESRF) X. Badel (KTH) J. Linnros (KTH) Thanks to: N.B. Larsen (RISØ) J.C. Grivel (RISØ) C. Gundlach (ESRF) Funding: Danish Fundamental Research Foundation &