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R&D on scintillation materials and photo-sensors for CALIFA.

R&D on scintillation materials and photo-sensors for CALIFA. I. Durán on behalf of CWG (IPNO, LUND, IEM/CHALMERSS, USC. Work performed at home laboratories Prototype definition: In-beam tests. Properties of scintillating crystals. Intrinsic energy resolution, density

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R&D on scintillation materials and photo-sensors for CALIFA.

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  1. R&D on scintillation materials and photo-sensors for CALIFA. I. Durán on behalf of CWG (IPNO, LUND, IEM/CHALMERSS, USC • Work performed at home laboratories • Prototype definition: In-beam tests

  2. Properties of scintillating crystals • Intrinsic energy resolution, density • Maximum light emission • hygroscopic • price !!!! • Long enough to stop and measure high energy p and  • High granularity in polar angle due to Lorentz boost.

  3. Matching of scintillators and photo-sensors properties. • Crystal quality, Surface treatment, Wrapping • Election of the adequate photo-sensor • Optical coupling • Light collection uniformity • Shaping time • T and V dependence

  4. R&D program: Crystal + photosensors • Push scintillation materials and photo-sensors producers. • Specify main characteristics for large scale production CsI(Tl), La3Br(Ce), La3Cl(Ce) and PMs, LAAPDs, PinD. In close contact with the Industry St.Gobain, AMCRYS, Lanzhou, SCIONIX,HAMAMATSU, Photonis… - CsI(Tl) has been retained for the Califa Barrel, offering an excellent trade-off performance/price. - LAAPDs provide the best results

  5. Barrel Crystals • Two CsI(Tl) providers have been retained: AMCRYS(Ukraine), Lanzhou (China) AMCRYS Best quality and price. Comercial experience. Lund/Dubna good contact. Lanzhou Very good crystal quality. Interest in NUSTAR/R3B Scientific collaboration?

  6. Wrapping the crystals • To maximise light collection crystals must be wrapped • Best results achieved using polished surfaces and ESR (VM2000)

  7. About Non-Uniformity • (USC)‏ • Light collection depends on the position where the primary energy was deposited. Why non-uniformity is a problem? • (LUND)‏ • (IPNO)‏ mask PM  source 137Cs CsI (Tl) crystal dL/L <1 % requested from manufacturers By the time being, we are getting ~ 2 – 4 %

  8. On the crystal's size Tests with realistic sizes following Barrel design Tests with small samples 1cm 13 cm M.Gascón USC

  9. On the crystal's size • (IPNO)‏

  10. CsI(Tl) with different LAAPD sizes • Different qualities received from Hamamatsu (Si thickness, frames, epoxi windows) PANDA Price 140 € unit (now ~500€)‏ Dimensions: 7x14 mm2 CMS/PANDA Price 110 € unit (now ~500€)‏ Dimensions: 10x10 mm2 R3B prototype Price (now ~2000 €)‏ Dimensions: 10x20 mm2 M.Gascón USC

  11. Energy resolution at Lund with 10x10 LAAPD (S8664)‏ V. Avdeichikov LUND

  12. Two CsI(Tl) with 20 x10 APDs FADC multichannel readout of CsI(Tl) crystals Digital filter avoid pile-up problems Time coincidence allow us add-back analysis M.Gascón USC

  13. APD´s drift problem • The APD's Gain drifts with both Voltage and Temperature G(V,T) = G(Vo,To)(1.03V[volt] – 1.02T[deg])‏ • T range must be kept low enough to allow V feedback • In any case, both V and T must be slow-controlled (HELP!!!)‏ I.Durán USC

  14. CsI(Tl) with XP1452 at IPN-O • XP1452 green extended bialkali (Quantum efficiency 30% at 420nm, 20% at 550 nm)‏ 9 stages 15 mm 35 mm 30 mm XP1452 • For CsI(Tl): Energy resolution of 5 - 5.5% seams reachable with XP1452 at 1MeV • Cross-Talk around 3 - 5 % (can be improved and easy to correct)‏ • Resolution degrades with magnetic field (main constraint)‏ • (IPNO)‏

  15. CsI(Tl) with Photodiodes at Lund + PDs do’nt require neither temperature nor voltage stability - Significantly worse energy resolution and higher threshold ~100 keV The gamma energy-resolution depends strongly on the PinD noise level. A low-capacity (15 pF) PD with low current (< 1 nA) can give a resolution close to what an APD can provide. V. Avdeichikov LUND

  16. Lanthanum-based crystals at IEM IEM-CSIC(Madrid)/ Chalmers

  17. Lanthanum-based crystals at IEM IEM-CSIC(Madrid)/ Chalmers

  18. Lanthanum-based crystals at IEM IEM-CSIC(Madrid)/ Chalmers

  19. LUND ProtoZero beam-tests USC IPN-O Different solutions will be tested

  20. CONCLUSIONS on R&D on scintillation materials and photo-sensors for CALIFA. • A lot of satisfactory work has been done • A lot of work remains to be done • Readout electronics and slow-control are open questions I. Durán – Gotenburgo 2008

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