P. Checchia Como 8th ICATPP1 LCcal * : a Calorimeter prototype for future Linear Colliders 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 …. TALK SUMMARY

P. Checchia Como 8th ICATPP2 Design principles From the LC Physics requirements: Tesla TDR solutions: Si W Shashlik (thanks to CALEIDO) 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 Alternatives: Cristals Fully compensating Ecal+Hcal

P. Checchia Como 8th ICATPP3 Prototype description Pb/Sc + Si 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) 45 layers 25 × 25 × 0.3 cm 3 Pb 25 × 25 × 0.3 cm 3 Scint.: 25 cells 5 × 5 cm 2 3 planes: ×.9 cm 2 Si Pads at: 2, 6, 12 X 0

P. Checchia Como 8th ICATPP4 Prototype (cntd) 3 Si planes Actual design: - Detector: 6x7 pads - Plane: 3x2 detectors Goal: shower-shower separation, position measurement, e/h identification: Pad dimension< shower dimension:.9x.9 cm 2 Longitudinal sampling: 3 planes Analogic RO VA hdr9c from IDEas See A. Bulgheronis talk for details Pad diode ac(old)- dc(new) coupled pcb contact with conductive glue

P. Checchia Como 8th ICATPP5 Construction details:Scintillator 3 mm Kuraray SCSN-61(25x25 cm 2 ) 3 mm Bicron BC-408 (25x25 cm 2 ) Machined with vacuum plate as holder Whole Production (>50 tiles) done in september 2002

P. Checchia Como 8th ICATPP6 To make the 2.4 cm radius curvature : middle temperature( ) oven Splicing with optical glue and a supporting tube : stable in >30 day time Fibers: Kuraray 1mm d. Y ppm multicladding Face polished and aluminized by sputtering

P. Checchia Como 8th ICATPP7 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

Test beam activity after a 2002 pre test with the 1 st layer only (2.1 X 0 ) at CERN two runs at Frascati Beam Test Facility (n × 50 – 750 MeV) detector tunable W target: 1.7, 2.0, 2.3 X magnet W slits LINAC Beam mA 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 x–y Si strips with a pitch of 240 m - They cover the central area of the prototype ( cm 2 ) LCcal beam trigger

P. Checchia Como 8th ICATPP9 Test beam activity : detector calibration define cell as the calibrated sum of the 4 longitudinal layers on the same lateral position:C i =b i j=1,4 a j L i j ( parameters) process in two steps: equalise the layer response at the same incoming energy L i j =b k /b i L k j minimise the Energy spread on the sum of 9 cells (iterative process) a j | min. width E cal = n=1,9 C n L1L1 L2L2 L3L3 L4L4 CiCi Si L1 Si L2 Si L3

P. Checchia Como 8th ICATPP10 Good linearity vs molteplicity 3 e - 2 e - 1 e - E E beam (MeV) 11.5% E N phe >5.1 /layer Cal(45 layers) ~ 250 MeV/Mip ~ 800Npe/GeV OK BTF (E ~500 MeV) Cern TB Photoelectron statistics negligble 2. Stocastic Term 11.5% as in MC 3.Light disuniformity <<10% Effects on resolution to be measured at SPS (August 2003) BTF test Test beam results: Linearity and Energy Resolution

P. Checchia Como 8th ICATPP11 E Cern TB 2003 E beam (GeV) 11.1% E E cal (GeV) e-e- pm saturates confirmed at high energy !!! E beam (GeV) Test beam results: Linearity and Energy Resolution E cal (GeV) 15 GeV e - 75 GeV

P. Checchia Como 8th ICATPP12 Si L1+L2 30 GeV electrons Test beam results: Si pad detector (Position Meas.) e - =2.16 mm =2.45 mm =3.27 mm =1.76 mm y pad –y telescope (cm) y telescope (cm) y pad Si L2 (cm) Cern TB 2003 Si L1 Si L2 Si L3

P. Checchia Como 8th ICATPP13 10 GeV electrons Test beam results: Si pad detector (Position Meas.) 10 GeV simulated electrons Position resolution 2.5mm not far from Monte Carlo =2.5 mm PRELIMINARY analysis: pad noise subtraction not optimised

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

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

P. Checchia Como 8th ICATPP16 BTF test Test beam results: Si Pad two particle separation Two electrons with energy 750 MeV Y silicon chambers X silicon chambers exhaustive analysis not fully accomplished NB: not fully equipped+ problematic channels First layer Second layer Third layer

P. Checchia Como 8th ICATPP17 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 ~ % / 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 ICATPP18 backup

P. Checchia Como 8th ICATPP19 Detector Assembling:

P. Checchia Como 8th ICATPP20 PMs Scintill. Piani Si Fibres with PM support structure LCCAL in BTF (Frascati) Fibres faced to PMs

P. Checchia Como 8th ICATPP21 Test beam results CALORIMETER (2.1 X 0 ) 4 layers m.i.p.check light output and uniformity in Light collection: Ratio signal/sigma lower limit for photoelectrons N phe >5.1 /layer cal(45layers):>220 phe/m.i.p. good uniformity: Simulated Light collection disunifority(20%)