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Accelerator Physics and detector goals Scintillator calorimeters Conclusions

Scintillator calorimeters at ILC Jaroslav Cvach Institute of Physics ASCR, Prague CALICE Collaboration. Accelerator Physics and detector goals Scintillator calorimeters Conclusions. = International Linear Collider.

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Accelerator Physics and detector goals Scintillator calorimeters Conclusions

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  1. Scintillator calorimeters at ILCJaroslav CvachInstitute of Physics ASCR, PragueCALICE Collaboration Accelerator Physics and detector goals Scintillator calorimeters Conclusions Scintillators and ILC

  2. = International Linear Collider • e+e- machine with two beam pipes each at energy 250 GeV with cold rf cavities • Lower energy than Large Hadron Collider (LHC, CERN, Geneva) but more clean interactions – precision physics • LHC will make discovery, ILC will measure it • Detector design goes in parallel with accelerator development Scintillators and ILC

  3. Physics and detectorsgoals • Interesting reactions e+ e- -> H,W, Z, t, … • production of heavy particles decaying into jets • Goal: to reach energy resolution for jets σE/E ≈ 30%/√E • measure every particle: • charged particles in the tracker • photons in electromagnetic calo • neutral hadrons inhadron calo • tracker in strong magnetic field • fine granularity in calorimeters W and Z production Scintillators and ILC

  4. Four detector concepts Muon tracker ECAL + HCAL vertex / tracker • Detectors significantly smaller than at LHC • Three classical detectors SiD, LDC, GLD in advance stage • DREAM detector relies on • Separate measurement of electromagnetic shower component fem using Čerenkov light • Scintillation fibres measure total hadron energy, clear fibers Č light from electromagnetic energy (π0→γγ) fem • complementary information about both showers suppresses fluctuations in energy measurement • See e.g., N. Akchurin etal., NIM A537 (2005) 537 • R&D programs ongoing, do not follow necessarily the detectors but rather different technologies Scintillators and ILC

  5. Scintillator for calorimeter • Careful R&D program to select scintillator, shape, WLS fibre, wrapping, photodector position, homogeneity, … • Final choice: scintillator tiles 5 mm thick of 3 dimensions: 30x30 mm,… • polysterene + 1.5% PTP+ 0.01% POPOP from UNIPLAST, Vladimir, Russia, molding (PHENIX, HERA-B, LHC-B electromagnetic calorimeters) • Maximum of emmision spectrum at 420 nm • LY ~ 1.5x lower than Bicron 408 • WLS fibre Kuraray Y11(200), ⌽1mm, different geometry of groove, fibre bent at T ~ 100°C • Reflector foil super-radiant VN2000 from 3M for top and bottom • Chemical treatment of tile sides, 2.5% cross-talk over sides • LY uniformity over tile surface ~ 4% 30 mm 60 mm 120 mm Light yield in tiles of cassettes 1-26 Scintillators and ILC

  6. Hadron calorimeter prototype • SiPM properties • Sensitive area - 1x1 mm2, Matrixof1156 (34х34) pixels operating in Geiger mode • A fired pixel gives ΔQ= V∙C • So net signal ~ number of detected photons • Limited dynamic range due to limited number of pixels  saturation at N ~ Npixels • Light registration efficiency QE(~80%) x εGeiger(~60%)х εgeom(~35%)~ 17%, with maximum for green light • First massive use of SiPMs • Producer PULSAR, Moscow in coll. with MEPHI, DESY • Tested and assembled in tiles by ITEP and MEPHI Moscow • Calorimeter construction at DESY Hamburg • Tests in beams of DESY, CERN, FNAL 38 planes of scintillating detectors Light from a tile is read out via WLS fiber and SiPM Tile 3х3 cm2,WLS fiber,SiPM SiPM Scintillators and ILC

  7. NOISE AT ½ MIP(7.5 pixels) GAIN /103 CROSS TALK SIPM CURRENT Parameters of 10000 tested SiPMs Gain~106 (ΔV~3V, C~50fF) Noise~2MHz, exponentially falls with threshold Optical inter pixel crosstalk<~0.3 restricted operation voltage Insensitive to magnetic field (Tested up to 4 T) Saturation due to the finite number of pixels SATURATION CURVE E.Tarkovsky, ITEP, ILC 2006, Valencia Scintillators and ILC

  8. Test calorimeter at CERN SiPM wavelength shifting fibre plastic scintillator • CALICE Collaboration – more than 200 physicists all over the world – calorimeter design • Task: developement and tests of different technologies in R&D • European laboratories supported by EU via EUDET grant – 2006-9 (7 M€) • Calorimeters in tests at CERN, 2006-7, 2008 at FNAL • Two scintillator calorimeters in line (hadron+TC) – same technology, different scintillator shape • First massive use of novel photodector – SiPM (> 8000 pcs) • Aim: proof of principles – calorimeter as „tracking“ device Scintillators and ILC

  9. Event with 2 hadrons after reconstruction. Two showers separated in depth are visible reconstruction algorithm: Deep Analysis (V. Morgunov, ITEP, DESY) applied to HCAL only clusters grouped according to topology and hit amplitude Separate: EM and HAD shower components + neutrons (= isolated hits) DATA ECAL HCAL Scintillators and ILC

  10. Scintillator ECALUniv. Kyoto & Shinshu EM-Scintillator-layer model TT Oct 06 Tungsten ASIC WLSF scintillator 4cm MPPC Flexsheet MPPC Tungsten ASIC 1cm MPPC Tungsten particle • Orthogonal scintillator strips in x & y layer from Kuraray • Size: 1cm x 5cm x 2mm • 30 layers  10 M channels • hole outside shielded by TiO2 • Readout with & w/out WLS fibre by Multi-Pixel Photon Counter (Hamamatsu) (see Satoru Uozumi at the poster session) Cast-Mega-strip Extruded-strip T.Takeshita Scintillators and ILC

  11. Future To DAQ Module data concentrator 38 layers 80000 tiles Layer data Concentrator (control, clock and read FEE) FEE: 32 ASICs (64-fold) 4 readout lines / layer Instrument one tower (e.m. shower size) + 1 layer (few 1000 tiles) M. Danilov, ITEP • Decision about ILC 2010(?) + 7 years of construction • Next prototype of scintillator hadron calorimeter will be built in 2009 (EUDET) • geometry of the final calorimeter (integration of calibration and read-out electronics • Direct coupling of SiPM to tile – is it advantegeous? • Homegeneity from tile with WLS fibre / direct coupling • Final calorimeter will have ~ 3000 m2 scintillator Scintillators and ILC

  12. Conclusions • The next generation of calorimeters for the International Linear Collider aim at significant improvement of the energy resolution • Two basic methods how to achieve it in scintillator calorimeters: • Detection of scintillation and Čerenkov light in parallel • High granular tile calorimeter with Si diodes operated in Geiger mode (SiPM, MPPC, … ) as photodectors • CALICE Coll. – first massive use of SiPMs (<10000) • Intensive R&D program ongoing aiming at Engineering Design Report in 2010 with technical solutions and cost estimates as a world-wide activity • Calorimeter prototypes use plastic scintillators at the moment (not inorganic - the subject of this conference)  • New photodectors can find use also in applications with inorganic scintillators  Scintillators and ILC

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