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LCcal * : a Calorimeter prototype for future Linear Colliders

LCcal * : a Calorimeter prototype for future Linear Colliders. TALK SUMMARY. Design principles Prototype description Construction details Test Beam results Conclusions and Future plans.

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LCcal * : a Calorimeter prototype for future Linear Colliders

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  1. LCcal*: a Calorimeter prototype for future Linear Colliders TALK SUMMARY • Design principles • Prototype description • Construction details • Test Beam results • Conclusions and Future plans * Contributors (Como, ITE-Warsaw, LNF, Padova, Trieste): M. Alemi, A.Anashkin, M. Anelli, M.Bettini, S.Bertolucci, E. Borsato, M. Caccia, P.C, C. Fanin, J.Marczewski, S. Miscetti, B.Nadalut, M. Nicoletto, M. Prest, R. Peghin, L. Ramina, F. Simonetto, E. Vallazza …. P. Checchia Como 8th ICATPP

  2. Design principles From the LC Physics requirements: Tesla TDR solutions: • Si W • Shashlik (thanks to CALEIDO) • Cristals • Fully compensating Ecal+Hcal Alternatives: Proposed solution: Keep SiW advantages (flat geometry, high granularity) Erec. not from Si but from Scintillator-WLS fibers Reduce (factor >10) the number of channels P. Checchia Como 8th ICATPP

  3. Prototype description Pb/Sc+Si • 45 layers • 25 × 25 × 0.3 cm3 Pb • 25 × 25 × 0.3 cm3 Scint.: 25 cells 5 × 5 cm2 • 3 planes: • 252 .9 × .9 cm2 Si Pads • at: 2, 6, 12 X0 Scintillation light transported with WLS σ tail fibers: Cell separation with grooves in Sc. plates with Tyvec strips inside Coupled with clear fibers (to PM) P. Checchia Como 8th ICATPP

  4. Prototype (cntd) 3 Siplanes • Goal: shower-shower separation, position measurement, e/h identification: • Pad dimension< shower dimension:.9x.9 cm2 • Longitudinal sampling:3 planes • Analogic RO VA hdr9c from IDEas • See A. Bulgheroni’s talk for details Pad diode ac(old)-dc(new) coupled Actual design: - Detector: 6x7 pads - Plane: 3x2 detectors pcb contact with conductive glue P. Checchia Como 8th ICATPP

  5. 3 mm Kuraray SCSN-61 (25x25 cm2) 3 mm Bicron BC-408 (25x25 cm2) Construction details:Scintillator Machined with vacuum plate as holder Whole Production (>50 tiles) done in september 2002 P. Checchia Como 8th ICATPP

  6. Fibers: Kuraray 1mm d. Y11 300 ppm multicladding Face polished and aluminized by sputtering To make the 2.4 cm radius curvature : middle temperature(500-700) oven Splicing with optical glue and a supporting tube : stable in >30 day time P. Checchia Como 8th ICATPP

  7. Detector Assembling: 45 Layers calorimeter prototype completely built in 2002 Fibres grouped into 25x4 bundles making a 4-fold longitudinal segmentation. Slots for the insertion of the 3 Si pad planes (Motherboard). Mechanical support for Photomultipliers in the 3x3 central cells P. Checchia Como 8th ICATPP

  8. detector LINAC Beam 1-500 mA W slits tunable W target: 1.7, 2.0, 2.3 X0 450 magnet Test beam activity • after a 2002 pre test with the 1st layer only(2.1 X0) at CERN • two runs at Frascati Beam Test Facility (n × 50 – 750 MeV) it is possible to tune the multeplicity..... • run at CERN SPS H6 beam line (e/ 5 – 150 GeV) All tests: two beam position monitors (telescope) put in front of the calorimeter. • - Each detector consisting of 400400 x–y Si strips with a pitch of 240 m • - They cover the central area of the prototype (9.5  9.5 cm2) LCcal trigger beam

  9. define ‘cell’ as the calibrated sum of the 4 longitudinal layers on the same lateral position: Ci=bij=1,4ajLij(4-1+9-1+16 parameters) • process in two steps: • equalise the layer response at the same incoming energy Lij=bk/bi Lkj • minimise the Energy spread on the sum of 9 cells(iterative process)aj|min. widthEcal=n=1,9Cn Test beam activity : detector calibration L4 L3 L2 L1 Ci Si L3 Si L2 Si L1 P. Checchia Como 8th ICATPP

  10. Good linearity vs molteplicity 1 e- 2 e- 3 e- Test beam results: Linearity and Energy Resolution BTF test EE 11.5%E Ebeam (MeV) • Photoelectron statistics negligble • Stocastic Term11.5% as in MC • Light disuniformity <<10% Effects on resolution to be measured at SPS (August 2003) Cern TB 2002 Nphe>5.1 /layer →Cal(45 layers) ~ 250 MeV/Mip ~ 800Npe/GeV OK also @ BTF (E ~500 MeV) P. Checchia Como 8th ICATPP

  11. Cern TB 2003 Test beam results: Linearity and Energy Resolution EE pm saturates confirmed at high energy !!! Ecal (GeV) e- 11.1%E Ebeam (GeV) Ebeam (GeV) 75 GeV 15 GeV e- P. Checchia Como 8th ICATPP Ecal (GeV) Ecal (GeV)

  12. =2.45 mm =2.16 mm e- Test beam results: Si pad detector (Position Meas.) Cern TB 2003 y pad Si L2 (cm) 30 GeV electrons y telescope (cm) Si L1+L2 =3.27 mm =1.76 mm Si L3 Si L2 Si L1 P. Checchia Como 8th ICATPP y pad –y telescope (cm)

  13. Test beam results: Si pad detector (Position Meas.) PRELIMINARY analysis: pad noise subtraction not optimised Position resolution  2.5mm not far from Monte Carlo 10 GeV electrons 10 GeV simulated electrons =2.5 mm P. Checchia Como 8th ICATPP

  14. 30 GeV e- Cern TB 2003 Test beam results: uniformity in (light) Energy response disuniformity < 2% correction from pad reconstruction can be applied! Ecal (GeV) x telescope ± 2% PRELIMINARY: cell border effects dominated by residual miscalibration x pad x (cm) ± 2% Cj y(cm) x telescope Cj-1 x pad x (cm) Ecal (GeV)

  15. Test beam results: ( e/ rejection) the redundancy of the information on the linear/lateral shower development makes the rejection very easy (difficult to quantify below 10-3 due to beam contamination) Cern TB 2003 30 GeV e- 30 GeV e- 30 GeV 30 GeV E Si pad Layer 1 E cal Layer 1 50 GeV e- Si pad Layer 2 30 GeV e- 30 GeV 75 GeV shower variance:

  16. Test beam results: Si Pad two particle separation exhaustive analysis not fully accomplished Two electrons with energy 750 MeV X silicon chambers Y silicon chambers First layer BTF test Second layer NB: not fully equipped+ problematic channels Third layer P. Checchia Como 8th ICATPP

  17. Conclusions and Future plans • A calorimeter prototype with the proposed technique has been built and fully tested. All the results are preliminary. • Energy and position resolution as expected: E/E ~11.-11.5% /E, pos~2 mm (@ 30 GeV) • Light uniformity acceptable. • e/ rejection very good ( <10-3). • Two particle separation results coming soon. • Next steps: include a calorimeter made following this technique into the general LC simulation and Pattern recognition. • Combined test with Hcal (?) P. Checchia Como 8th ICATPP

  18. backup P. Checchia Como 8th ICATPP

  19. Detector Assembling: P. Checchia Como 8th ICATPP

  20. PM’s Fibres with PM support structure Fibres faced to PMs Scintill. Piani Si P. Checchia Como 8th ICATPP LCCAL in test @ BTF (Frascati)

  21. 4 layers m.i.p.→check light output and uniformity in Light collection: Ratio signal/sigma →lower limit for photoelectrons Test beam results CALORIMETER (2.1 X0) Nphe>5.1 /layer → cal(45layers):>220 phe/m.i.p. good uniformity: Simulated Light collection disunifority(20%) P. Checchia Como 8th ICATPP

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