1. June 4, Scint 2007 Scintillators and ILC 1 Scintillator calorimeters at ILC Jaroslav Cvach Institute of Physics ASCR, Prague CALICE Collaboration 1.Accelerator 2.Physics and detector goals 3.Scintillator calorimeters 4.Conclusions

2. June 4, Scint 2007 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

3. June 4, Scint 2007 Scintillators and ILC 3 Physics and detectors goals Interesting reactionsInteresting reactions e + e - -> H,W, Z, t, … production of heavy particles decaying into jets Goal: to reach energy resolution for jets σ E /E ≈ 30%/√EGoal: to reach energy resolution for jets σ E /E ≈ 30%/√E W and Z production measure every particle: charged particles in the tracker photons in electromagnetic calo neutral hadrons in hadron calo  tracker in strong magnetic field  fine granularity in calorimeters

4. June 4, Scint 2007 Scintillators and ILC 4 Four detector concepts 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 f em using Čerenkov light –Scintillation fibres measure total hadron energy, clear fibers Č light from electromagnetic energy (π 0 →γγ)  f em –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 vertex / tracker ECAL + HCAL Muon tracker

5. June 4, Scint 2007 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% Light yield in tiles of cassettes 1-26 60 mm 120 mm 30 mm

6. June 4, Scint 2007 Scintillators and ILC 6 Hadron calorimeter prototype SiPM Tile 3х3 cm 2, WLS fiber,SiPM 38 planes of scintillating detectors Light from a tile is read out via WLS fiber and SiPM SiPM properties Sensitive area - 1x1 mm 2, Matrix of 1156 (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  ~ N pixels Light registration efficiency  QE(~80%) x ε Geiger (~60%)х ε geom (~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

7. June 4, Scint 2007 Scintillators and ILC 7 Parameters of 10000 tested SiPMs NOISE AT ½ MIP(7.5 pixels) CROSS TALKSIPM CURRENT GAIN /10 3 SATURATION CURVE E.Tarkovsky, ITEP, ILC 2006, Valencia Gain ~10 6 (ΔV~3 V, C~50 fF) 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

8. June 4, Scint 2007 Scintillators and ILC 8 Test calorimeter at CERN 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 wavelength shifting fibre plastic scintillator SiPM

9. June 4, Scint 2007 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

10. June 4, Scint 2007 Scintillators and ILC 10 Scintillator ECAL Univ. Kyoto & Shinshu Orthogonal scintillator strips in x & y layer from Kuraray Size: 1cm x 5cm x 2mm 30 layers  10 M channels hole outside shielded by TiO 2 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 MPPC EM-Scintillator-layer model TT Oct 06 MPPC Tungsten MPPC WLSF scintillator Flexsheet Tungsten particle 1cm 4cm ASIC

11. June 4, Scint 2007 Scintillators and ILC 11 Future 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 m 2 scintillator 38 layers 80000 tiles FEE: 32 ASICs (64-fold) 4 readout lines / layer Layer data Concentrator (control, clock and read FEE) Module data concentrator Instrument one tower (e.m. shower size) + 1 layer (few 1000 tiles) To DAQ M. Danilov, ITEP

12. June 4, Scint 2007 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