1. 1 First tests of LCCAL prototype at BTF LCCAL: Official INFN R&D project, official DESY R&D project PRC R&D 00/02 Contributors (Como, LNF, Padova, Trieste): M. Alemi, M.Bettini, S.Bertolucci, E. Borsato, A.Bulgheroni, M. Caccia, P.Checchia, C. Fanin, G. Fedel, J.Marczewski, S. Miscetti, M. Nicoletto, M. Prest, R. Peghin, L. Ramina, E. Vallazza. ECFA-DESY LC Workshop 2 April 2003 Amsterdam Construction of prototype Description of BTF Silicon Pads status First results from test run Talk Summary:

2. 2 (Slightly reduced to cope with budget:45) 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): (Reduced to cope with budget:252) Description of the proposed hybrid em calorimeter Old slide from P.Checchia at last ECFA meeting in Praha

3. 3 Status of Tile –PB calorimeter early November 2002 Scintillator tiles Si pad detectorsFibres Detector assembling The tile-Pb calorimeter is fully mounted! Steps and status: Old slide from P.Checchia at last ECFA meeting in Praha

4. 4 The tiles were surrounded by an Al support structure for PMs 44 bundles of fibers were connected to PMs, the optical coupling between fibers and PMs was left “in air” (i.e. no optical grease) The calorimeter was covered by PVC and made light tight. As soon as the calorimeter was ready we went for testing at BTF Status of Tile –PB calorimeter end of November 2002 Final assembly done @ LNF where:

5. Areal view and BTF layout Da  ne Linac BTF test facility Located @ Frascati close to Da  ne machine

6. 6 gun focusing Positron converter focusing Length: 60 m Maximum energy: 850 (550) MeV e  (e  ) Transverse emittance: < 1 (5) mm mrad e  (e  ) mm mrad Energy spread: < 1% (2%) e  (e  ) Pulse duration:10 ns (RF = 2.865 GHz) Max repetition rate:50 Hz Da  ne Linac

7. 7 W slits detector tunable W target: 1.7, 2.0, 2.3 X 0 45 0 magnet W slits LINAC Beam 1-500 mA Single particle production at BTF In the transfer line from Linac to BTF it is possible to tune the multeplicity.....

8. 8 N. of electrons Events in peak Events Energy in calorimeter Measured energy in BTF monitor calorimeters reflects the Poisson distribution of the number of produced particles  1 means P(0)  P(1)  37% Example of single particle production at BTF

9. 9 e  and e  Energy: 50 – 850 (550) MeV e  (e  ) Repetition rate: 24 Hz (will be 49 Hz) Pulse Duration 10 ns (will be  1.5 ns) Single particle production (1% energy selection) Maximum current/pulse is 500 mA… … but up to 10 3 allowed electrons/sec Upgrade asked for 10 10 allowed electrons/sec 100 m 2 Experimental Hall Summary of BTF characteristics...

10. 10 Test Beam Dic 2002: layout of prototype  25×4 cells 5×5 cm2  Fibers grouped in four longitudinal sectors (L1-L4) L1/L2/L3/L4 = 4/7/11/23 PB/Sc layers (2.3 : 4: 6.3: 13.2) X 0. 1 2 3 4 5 6 7 8 9 MultiAnode PMs under test to readout all cells...... X Z Y Empty space for insertion of Si pads  The 3x3 central cells (1-9) readout in each longitudinal sector by PMs.  Other 4x4 surrounding cells readout integrating along Z and merging few contiguous cells. Used for leakage.

11. 11 Motorized table LCCAL VME+Camac (users) VME (diagnostics) Calo 1 Calo2 HV Test Beam Dic 2002: LCCAL in position... BTF just started.. LCCAL proto was one of the first user!

12. 12 Test Beam Dic 2002: more pictures... Strange yellow beam P.Checchia and G.Mazzitelli (BTF responsible)

13. 13 Test Beam Dic 2002: equalization procedure... Shower longitudinal profile 2.3 X 0 4.0 X 0 6.3 X 0 13.2 X 0 Ene L1(Counts)Ene L2(Counts) Ene L3(Counts)Ene L4(Counts) Electron beams of 490 MeV used to test the energy response of each cell. A first cross-calibration of the PM gains was done by: 1.Minimizing energy res. 2.Lowering gains to reduce saturation No exact knowledge of beam size and position. Just 3 days of running.. Still.. compare cell 4,6

14. 14 Energy in tower after gain equalization Energy in tower before gain equalization 2 nd electron Test Beam Dic 2002: first look at response & resolution Cell 4 Tower comparison (ADC counts) Cell 4 vs 6 No bad for the first try.... still some hints of saturation with 2 particles

15. 15 Upgrade of prototyping during last 4 months PCBs also fully developed (see next talk by A.Bulgheroni) Each motherboard mounts 3x2 Si wafers, for a total of 18x14 pads. SI Pads detector:  20 detectors produced by IET (Warsaw) : - 1 used on the old Test beam - 16 OK and assembled on 3 PCB - 1 noisy, 2 bad 6 cm 7 cm Problems, adopted solutions, running conditions and future plans still refer to Bulgheroni’s talk

16. 16 Silicon Pads insertion in prototype PCB with SiPad inserted inside prototype the 28-03-03 Picture 1 HERE

17. 17 Last Friday a 1 week data taking started. Improvements: Si Pads inserted Two beam position monitors 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) Running @ BTF in 2003

18. 18 easier life during data taking... HV monitor & setting remotely controlled movement of table remotely controlled a faster DAQ Large test program underway.. energy scan at low energy: 140 – 750 MeV energy response & resolution for 1-2-3 impinging particles a more stable equalization procedure scanning along cell and pads in progress Running @ BTF in 2003 Moreover

19. 19 Test Beam Mar 03: Beam monitor The beam position monitor allow us to control the particle multeplicity Typical beam size:  x of few mm  y of  0.5cm 490 MeV

20. 20 Test Beam Mar 03: first look at response vs cell profiles E cell (a.u.) Given the small beam size we tried to position the beam as well as possible inside the cell. E cell (a.u.) Example of cell boundaries for central cell. In red (green) the x-y position of the events with 1 hit and Energy  (  )150 counts. Scan along cell is in progress  10%

21. 21 Calibration applied 3 e - 2 e - 1 e - Test Beam Mar 03: Energy spectra for 1-2-3 electrons No calibration applied 1 e - 2 e - 3 e - Test of calibration procedure on central cell. multeplicity from ext. strips no gaussian tails disappear linearity and resolution improve Calibration done after a first round of HV setting to reduce saturation

22. 22 Test Beam Mar 03: Energy linearity E cal (MeV) E beam (MeV) 2 electrons 3 electrons A larger energy region can be approximately scanned merging dat with single and multiple electrons  Linearity preserved

23. 23 Test Beam Mar 03: Energy resolution I Resolution for single electrons on the expected ball park! “Slightly” worse resolution for multiple electrons... probably due to overlapping multiple hits on ext. strips EEEE E beam (MeV) 11.5%  E Single electron 2 electrons 3 electrons EEEE Merging 1-2-3 electrons E beam (MeV)

24. 24 Test Beam Mar 03: Energy resolution & linearity  N phe >5.1 /layer → cal(45 layers):>220 phe/m.i.p. ~ 250 MeV/Mip → 800-900 Phe/GeV  Light uniformity better than 20% OK also @ BTF From Cern TB with first longitudinal sector only PRELIMINARY CONCLUSIONS.. 1.Photoelectron stat. negligible 2.Sampling term 11.5% as in MC 3.Uniformity of light collection still at a level < 10%-20% using all layers. Effect on resolution to be evaluated as eventual constant term at next Cern TB. 4.Expectations by MC

25. 25 Test Beam Mar 03: distribution of “fired” Si Pads First layer Second layer Xpad Ypad Qpad (a.u.) Ypad Nev Xpad Yes ! They are FIRING

26. 26 Test Beam Mar 03: position resolution at low energy Ypad (cm) Yb (cm) Ypad-Yb (cm) Just for fun : online correlation plot between position given by pads and external strips.  show only Y direction (since Xb is small!!)  No clustering tried  fast weighted average (Y-centroid) of firing Si pads with Q  5  Q Still: a clear correlation and a space resolution of 6-7 mm are found to be compared with  x,y of 2 mm found @ 25 GeV Ebeam = 490 MeV

27. 27 Conclusions and perspectives The LCCAL prototype is  fully working! - more Si Pads are under constructions - the third Si layer will be fully equipped. - multianode PMs to be installed in late autumn. Needs to start the simulation of this hybrid technique in LC software After a first learning phase in Nov 02 a succesfull test run with the whole prototype is under way at the BTF in Frascati. Energy response and resolution as expected! Work is in progress to understand discriminating power of multiple hits by merging Silicon and Energy information. Two test beams at Higher Energy in preparation: -PS (June 2003 ??) SPS (August 2003)