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P. Lecoq CERN 1 February 2015 FCC meeting, CERN, February 3 d, 2015 Inorganic scintillators Trends and perspectives Paul Lecoq CERN, Geneva This work is performed in the frame of the ERC Advanced Grant Agreement N338953TICAL Slide 2 P. Lecoq CERN February 2015 2 FCC meeting, CERN, February 3 d, 2015 25 years of SCINT community actions New crystals development PWO La halide family LSO, LYSO, LGSO, LuAP, LuYAP, LuAG, . Main emphasis (application driven: HEP & MI) was on: Understanding the material High light yield Good energy resolution (non-uniformity) Short decay time (for high event rate) Good radiation hardness (defect studies, compensation doping) Developping/adapting production technologies Czokralsky and Bridgeman for reacing desired specifications Investigating new technologies (mPD, ceramics,thin films, nano) Slide 3 P. Lecoq CERN February 2015 3 FCC meeting, CERN, February 3 d, 2015 Why fast timing in HEP? Search for rare events implies High luminosity accelerators Rate problems Pile-up Time of Flight techniques can alleviate the pile-up problem and help improving energy resolution, but: Current state of the art for Alice expt: 75ps Current state of the art for PET demonstrators: 140ps Need for a finely segmented calorimeter with 10ps time resolution TICAL 4D Time Imaging Calorimeter Slide 4 P. Lecoq CERN February 2015 4 FCC meeting, CERN, February 3 d, 2015 SiPMCrystalelectronics tt t kth pe = t t Conversion depth + t k ph Scintillation process + t transit Transit time jitter + t SPTR Single photon time spread + t TDC TDC conversion time Random deletion 1 Absorption Self-absorption Random deletion 2 SiPM PDE Unwanted pulses 2 DCR Unwanted pulses 1 DCR, cross talk Afterpulses Slide 5 P. Lecoq CERN February 2015 5 FCC meeting, CERN, February 3 d, 2015 New research directions Besides all factors related to photodetection and readout electronics the scintillator contributes to the time and energy resolution through: 1.The scintillation mechanism Light yield, Rise time, Decay time P. Lecoq et al, IEEE Trans. Nucl. Sci. 57 (2010) 2411-2416 2.The light transport in the crystal Time spread related to different light propagation modes 3.The light extraction efficiency (LY LO) Impact on photostatistics Weights the distribution of light propagation modes Slide 6 P. Lecoq CERN February 2015 6 FCC meeting, CERN, February 3 d, 2015 Ways to a faster rise time? Rise time is to a large extent related to the multiple scattering and thermalization of hot primary e-h pairs More studies needed for self activated scintillators Probability for low energy transfer from ionizing radiation Direct excitation of the luminescent center It would be interesting to measure the rise time of PWO, BGO, CeF3 Cross luminescence: Core-Valence luminescence Sub ns rise time and decay time But UV-VUV emission (not maching SiPM QE) High donor band: ZnO, CuI, PbI2 Derenzo, NIMA 486 (2002) 214-219 Cerenkov Quantum dots????? Slide 7 P. Lecoq CERN February 2015 7 FCC meeting, CERN, February 3 d, 2015 Light generation in a scintillator Rare Earth 4f 5d Slide 8 P. Lecoq CERN February 2015 8 FCC meeting, CERN, February 3 d, 2015 Wide emission spectrum from UV to IR Ultrafast emission in the ps range Independant of temperature Independant of defects Absolute Quantum Yield W h /W phonon = 10 -8 /(10 -11 -10 -12 ) 10 -3 to 10 -4 ph/eh pair Higher yield if structures or dips in CB? Interesting to look at CeF3 Hot intraband luminescence M. Korzhik, P. Lecoq, A. Vasilev, SCINT2013 paper TNS-00194-2013 Slide 9 P. Lecoq CERN February 2015 9 FCC meeting, CERN, February 3 d, 2015 CeF 3 hot intraband luminescence V. Nagirnyi, S. Omelkov, Tartu, Estonia Fast interband hole luminescence < 200ps Fast 5ns CeF3 luminescence Fast interband e - luminescence < 200ps Regular 20ns CeF3 luminescence Tartu electron gun, 200keV, 200ps Slide 10 P. Lecoq CERN February 2015 10 FCC meeting, CERN, February 3 d, 2015 Transient absorption M-Korzhik Slide 11 P. Lecoq CERN February 2015 11 FCC meeting, CERN, February 3 d, 2015 Transient absorption Experimental bench to prove the conceptTwo photons(2,97+3.16eV) absorption in 1 cm thick PWO R&D to combine ionization and transient absorption is planned within AIDA-II and TICAL: 4D Time Imaging Calorimeter ERC project M-Korzhik Slide 12 P. Lecoq CERN February 2015 12 FCC meeting, CERN, February 3 d, 2015 Transient absorption M-Korzhik Slide 13 P. Lecoq CERN February 2015 13 FCC meeting, CERN, February 3 d, 2015 CdSe Nanosheets Exciton/biexciton emission obtained in the lab using LSO + CdSe nano deposition excited with blue laser. Electron pulse excitation experiments to come. Stimulated photoluminescence due to exciton quantum confimenet in CdSe nanoplatelets 100 m layer of CdSe nanoplatelets deposited on 1mm thick LSO crystal by J. Grim, IIT, Genova P. Lecoq, J.Grim, I.Moreels, SCINT conference Berkeley, June 2015 R. Turtos Matinez, CERN 525nm Slide 14 P. Lecoq CERN February 2015 14 FCC meeting, CERN, February 3 d, 2015 Light Transport -49 < < 49 Fast forward detection 17.2% 131 < < 229 Delayed back detection 17.2% 57 < Fast escape on the sides 54.5% 49 < < 57 and 123 < < 131 infinite bouncing 11.1% Improving light extraction efficiency at first hit on coupling face to photodetector is the key Slide 15 P. Lecoq CERN February 2015 15 FCC meeting, CERN, February 3 d, 2015 Photonic crystals Crystal Crystal- air interface with PhC grating: >c>c Total Reflection at the interface Extracted Mode >c>c Nanostructured interface allowing to couple light propagation modes inside and outside the crystal air >c>c Slide 16 P. Lecoq CERN February 2015 16 FCC meeting, CERN, February 3 d, 2015 Use large LYSO crystal: 10x10mm 2 to avoid edge effects 6 different patches (2.6mm x 1.2mm) and 1 (1.2mm x 0.3mm) of different PhC patterns 045 Photonic crystals A. Knapitsch et al, Photonic crystals: A novel approach to enhance the light output of scintillation based detectors, NIM A268, pp.385-388, 2011 Review on photonic crystal coatings for scintillators A. Knapitsch, P. Lecoq International Journal of Modern Physics A Vol. 29 (2014) 1430070 (31 pages) Slide 17 P. Lecoq CERN February 2015 17 FCC meeting, CERN, February 3 d, 2015 Chiral nanophotonic waveguide Controlling the flow of light with nanophotonic waveguides Transverse quantum confinement of guided photons strong spin orbit coupling Allows scattering of light by a nonoparticle at the surface of the nanofiber to be redirected in the direction of the fiber -49 < < 49 Fast forward detection 17.2% 131 < < 229 Delayed back detection 17.2% 57 < Fast escape on the sides 54.5% 49 < < 57 and 123 < < 131 infinite bouncing 11.1% Can be used to redirect in the direction of the photodetector >50% of the light emitted at large angle Slide 18 P. Lecoq CERN February 2015 18 FCC meeting, CERN, February 3 d, 2015 New production technologies Micro-Pulling-Down: Marie Curie Rise-INTELUM project recently approuved CERN coordinator Ce doped LuAG Sintillator undoped LuAG Cerenkov 30cm 2mm Slide 19 P. Lecoq CERN February 2015 19 FCC meeting, CERN, February 3 d, 2015 New production technologies Transparent Ceramics Reduced production cost Increased activator concentration Increased uniformity of doping Improved mechanical properties Production of large transparent samples of various shapes Potential to fabricate phases that can not be grown from melt Courtesy N. Cherepy, S. Payne, LLNL Slide 20 P. Lecoq CERN February 2015 20 FCC meeting, CERN, February 3 d, 2015 New production technologies Thin films ZnO:Ga thin films on Si(100) are deposited by reactive DC magnetron sputtering of zinc in oxygen/argon mix, followed by vacuum annealing Courtesy R. Williams, Wake Forest University 60 ps ZnO:Ga powder Slide 21 P. Lecoq CERN February 2015 21 FCC meeting, CERN, February 3 d, 2015Conclusions R&D in inorganic scintillators is moving fast Timing performance is becoming a key R&D focus for many applications (HEP, MI, Homeland security, ) Enabling technologies are being developped Crystal production Nanophotonics for the management of optical photons A rapidly moving field with an enormous industrial potential and demand 3D ranging Photo-electronic chips Quantum entanglement and quantum computing Etc.