1. Nantes — 2008, July 15-17 1 Analysis of results from EmCal beam test at CERN PS (and SPS) energies P. La Rocca & F. Riggi University & INFN Catania University & INFN Catania

2. Nantes — 2008, July 15-17 2 Outlook General considerations (cuts, selections,…) Temperature analysis Temperature – Amplitude correlation Inter-calibration at 3 GeV/c Energy resolution at 3 GeV/c Preliminary analysis of all PS and SPS energy runs

3. Nantes — 2008, July 15-17 3 Beamtest Set-up 64 towers MWPC Scintillators beam Čerenkov (at PS) PS BEAM: electrons and hadrons (0.5 – 6.5 GeV/c) (Čerencov detector to discriminate)  Electron and beam (pions) runs at 3 GeV/c in all towers.  Electron and beam momentum scans 0.5, 1, 2, 3, 5 and 6.5 GeV/c at 6 different locations (centers and boundaries of some modules).  Phi angle scans at 9°, 6° and 3° (for electrons and pions)  Large Z configuration  Cosmic runs

4. Nantes — 2008, July 15-17 4 SPS BEAM: electrons (5-80 GeV/c) / hadrons (20-100 GeV/c)  High statistics electron runs at 80 GeV/c in all towers for relative calibrations.  100 GeV hadrons for relative calibration comparison using the mip peak.  Electron momentum scans 5, 10, 20, 40, 60, 80, and 100 GeV/c at the centers of several towers, and at 2 cm steps crossing module boundaries in X and Y.  Hadron data at 20, 40, 60, 80, and 100 GeV/c to measure the hadron energy deposition distributions, and to measure hadron shower shapes.  Hadron measurements at 100 GeV/c at module boundaries in X and Y to investigate hadron shower shape dependence on position. Beamtest Set-up

5. Nantes — 2008, July 15-17 5 Working conditions 1/2 PS LED signals nSig > 50 17 < tmaxSig < 19 BEAM signals nSig < 50 11 < tmaxSig < 13.5

6. Nantes — 2008, July 15-17 6 Working conditions 2/2 SPS LED signals nSig > 100 16 < tmaxSig < 19 BEAM signals nSig < 100 5 < tmaxSig < 10

7. Nantes — 2008, July 15-17 7 Temperature analysis

8. Nantes — 2008, July 15-17 8 APD temperature dependence - In principle gain dependence on temperature quite similar for all APDs (see Giuseppe’s talk) - Temperature correction: LED(i tower, j run ) / LED(i tower, Ref) Problems: Jumps in the signal issued by the LED pulser (discussed by Rachid) No correlation in some towers LED correction applied only on few runs (first PS period) to study its effect on the energy resolution

9. Nantes — 2008, July 15-17 9 Tower Inter-calibration E(I) = A * c_I *AmpSig(I) * LED(I,J) / LED(I,Ref) Energy in tower I (run J): Temperature Correction Inter-calibration scale factors - 1st method: inter-calibration by MIPs - 2nd method: inter-calibration by minimization Both methods applied to 3 GeV runs (1015 - 1205) Absolute energy scale factor

10. Nantes — 2008, July 15-17 10 MIP SELECTION ->Isolation cut (cut less efficient for towers in the boarders) Background due to hadronic shower produced by pions After isolation cut PS amp_around = 0 SPS Inter-calibration by MIPs 1/3

11. Nantes — 2008, July 15-17 11 Inter-calibration by MIPs 2/3 3x3 cluster energy around tower (3,4) without calibrationwith calibration REF

12. Nantes — 2008, July 15-17 12 Inter-calibration by MIPs 3/3 Energy resolution for each individual tower - Values spanning from 7.2% to 11.7 % - Weighted mean 8.6%

13. Nantes — 2008, July 15-17 13 Minimization algorithm 1/2 Calibration factors  i calculated by the minimization of the quantity: where index i runs over the towers, index j over all calibration events A system 64x64 must be solved!

14. Nantes — 2008, July 15-17 14 Minimization algorithm 2/2 Energy resolution for each individual tower (4x4 inner towers) - Values spanning from 7.1% to 10.8 % - Weighted mean 8.1% The minimization algorithm seems to give slightly better results

15. Nantes — 2008, July 15-17 15 Tower Inter-calibration & energy resolution at η  0 Analysis repeated for other energies (longer runs): - MIP Inter-calibration done only for central towers (2 < row < 4 && 3 < col < 5) - for the estimation of the energy resolution selected only those events with the maximum amplitude in row = 3 and col = 4 Momentum (GeV/c) El. runs 0.51393 11397,1398 21464 31424 51423 6.51422 Momentum (GeV/c) El. runs 10410, 412 20407, 408, 409 40405, 406 60403, 404 80270 - 275 100397 - 400 SPSPS

16. Nantes — 2008, July 15-17 16 Energy resolution at η  0 1/3 0.5 GeV/c 1 GeV/c 2 GeV/c 3 GeV/c 5 GeV/c 6.5 GeV/c

17. Nantes — 2008, July 15-17 17 Energy resolution at η  0 2/3 10 GeV/c 20 GeV/c 40 GeV/c 60 GeV/c 80 GeV/c 100 GeV/c

18. Nantes — 2008, July 15-17 18 Energy resolution at η  0 3/3

19. Nantes — 2008, July 15-17 19 Conclusions Full analysis at 3 GeV/c (Temperature, calibration, energy resolution…) Analysis at all PS and SPS energies for central towers