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Scintillation light yield of Ce-doped LuAP and LuYAP pixel crystals

Scintillation light yield of Ce-doped LuAP and LuYAP pixel crystals. A . J. Wojtowicz 1) , W. Drozdowski 1) , M. Ptaszyk 1) Z. Galazka 2) , J.L. Lefaucheur 2). 1) Institute of Physics, N. Copernicus University, Torun, Poland 2) Photonic Materials Ltd, Bellshill, Scotland.

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Scintillation light yield of Ce-doped LuAP and LuYAP pixel crystals

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  1. Scintillation light yield of Ce-doped LuAP and LuYAP pixel crystals A.J. Wojtowicz 1), W. Drozdowski 1), M. Ptaszyk 1)Z. Galazka2), J.L. Lefaucheur 2) 1) Institute of Physics, N. Copernicus University, Torun, Poland 2) Photonic Materials Ltd, Bellshill, Scotland International Conference on Inorganic Scintillators and their Industrial Applications SCINT 2005, Crimea, Ukraine

  2. OUTLINE Introduction Light yield from pixel crystalsof LuAP and LuYAP; results 2R-model Results:intrinsic light yields and loss parameters;absorption Summary and conclusions A.J. Wojtowicz, Crimea, Sept. 2005

  3. INTRODUCTION LuAP: 8.34 g/cm3, 0.3 photofraction, 365 nm emission, 17-18 ns decay time,LY over 2xBGO (thickness!!)difficult to grow, hence LuYAP ClearPetTM project: 2x2x8 and 2x2x10mm pixels of LYSO and LuYAP A.J. Wojtowicz, Crimea, Sept. 2005

  4. PROBLEM: poor vertical and horizontal light yield ratio V2H initially as low as 0.3OTHER CRYSTALS (the highest measured V2H today):BGO 0.6LSO, LYSO 0.63LuAP 0.43LuYAP 0.56 A.J. Wojtowicz, Crimea, Sept. 2005

  5. SAMPLES Photonic Materials Ltd, PML2x2x10 mm pixels and 5x5x1 platesclose to 60 samples of LuAP, YAP and LuYAP, delivered in 2003-2005 BOULES (Czochralski):diameter up to 53 mm,cylinder length up to 130 mm A.J. Wojtowicz, Crimea, Sept. 2005

  6. LIGHT YIELD ENERGY SPECTRUM Na 22, LuYAP pixel, horizontal, gain 3 Positions of full energy peaks depend on the amount of scintillation light produced by gamma particle A.J. Wojtowicz, Crimea, Sept. 2005

  7. PEAK POSITONSvsENERGY * GAIN note offset: peak 1, 9% peak 2, 3.5% peak 3, 2.5% slope coefficient:peak position for gain 1 and energy 1MeV A.J. Wojtowicz, Crimea, Sept. 2005

  8. ENERGY SPECTRUM Na22, LuYAP pixel vertically gain 3 Third peak gone, less light, wider peaks A.J. Wojtowicz, Crimea, Sept. 2005

  9. PEAK POSITIONS vsGAIN * ENERGY gain 3 LuYAP pixel vertically V2H = 0.42 A.J. Wojtowicz, Crimea, Sept. 2005

  10. ENERGY SPECTRA Na22, LuAP pixel vertically variable gain A.J. Wojtowicz, Crimea, Sept. 2005

  11. PEAK POSITIONS VS GAIN VS GAIN * ENERGY A.J. Wojtowicz, Crimea, Sept. 2005

  12. ENERGY SPECTRA, Na22, LuAP pixel vertically X-axis offset shifted, gain rescaled: peaks coincide A.J. Wojtowicz, Crimea, Sept. 2005

  13. SINGLE PHOTOELECTRON SPECTRA variable gain A.J. Wojtowicz, Crimea, Sept. 2005

  14. PEAK POSITIONS from single photoelectron spectra gain variable note offset of -18.7 for gain of 600 true peak position is 28.7 instead of 10!! slope coefficient 0.049 A.J. Wojtowicz, Crimea, Sept. 2005

  15. SINGLE PHOTOELECTRON SPECTRA X-axis offset shiftedgain rescaled peak position is offset independent norm. to gain 1 0.049Hamamatsu R2059 1500 V A.J. Wojtowicz, Crimea, Sept. 2005

  16. SUMMARY OF LIGHT YIELD MEASURMENTS LuAP (PML) V2H= 1) 900/2104 = 0.43 2) 909/2247 = 0.40 3) 856/2068 = 0.41 4) 909/2122 = 0.43 5) 740/1837 = 0.40 6) 873/2110 = 0.41 7) 855/1982 = 0.43 LuYAP (PML) V2H = 1) 999/1774 = 0.56 2) 793/1614 = 0.49 3) 856/1712 = 0.50 4) 1186/2533 = 0.47 5) 1061/2555 = 0.42 6) 945/2271 = 0.42 A.J. Wojtowicz, Crimea, Sept. 2005

  17. 2R – model (2 rays model) Experimental grounds: early papers by Lempicki et al, recently Dujardin et al: LY depends mostly on heigth not on length or width A.J. Wojtowicz, Crimea, Sept. 2005

  18. 2R – model (2 rays model) Experimental points, Balcerzyk et al., 2005Solid line 2R-model A.J. Wojtowicz, Crimea, Sept. 2005

  19. SUMMARY OF RESULTS from 2R-MODEL Loss (cm-1) / LY(0) (phel/MeV) LuAP (PML) 1) 1.46 / 2780 2) 1.61 / 3050 3) 1.55 / 2780 4) 1.46 / 2800 5) 1.62 / 2500 6) 1.55 / 2830 7) 1.44 / 2610 LuYAP (PML) 1) 0.86 / 2100 2) 1.14 / 2010 3) 1.10 / 2120 4) 1.24 / 3210 5) 1.54 / 3420 6) 1.53 / 3040 A.J. Wojtowicz, Crimea, Sept. 2005

  20. 2R-MODEL, selected LuAP pixels Loss 1.4-1.6 cm-1, LY(0) =2800-3600 phel/MeV A.J. Wojtowicz, Crimea, Sept. 2005

  21. 2R-MODEL, selected LuYAP pixels Loss 0.8-1.5 cm-1, LY(0) =2200-3200 phel/MeV A.J. Wojtowicz, Crimea, Sept. 2005

  22. Absorption, undoped LuAP, plate Corrections: Fresnel reflection, constant term A.J. Wojtowicz, Crimea, Sept. 2005

  23. Absorption, LuAP:Ce pixel transversally Corrections: Fresnel reflection, constant term A.J. Wojtowicz, Crimea, Sept. 2005

  24. Summary and conclusions We have introduced 2R-model to describe LY dependence on height of differently shaped crystals The model can be used to describe the pixel shaped crystals for PET The model allows to estimate intrinsic scintillation light yield and loss parameter from measurements of vertical and horizontal light yields Intrinsic light yields of LuAP and LuYAP are close. Loss parameter of LuAP at 1.4 to 1.6 cm-1 is higher than LuYAP (0.8 cm-1) The loss consists of Rayleigh term, constant term and unidentified UV absorption A.J. Wojtowicz, Crimea, Sept. 2005

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