1. Jean Favier LAPP CERN Physics and soft meeting 23/04/04 Why Monte-Carlo ? To understand and separate influences of parameters (ex: fog d, distorsions,m.i.p grain density) on efficiency To guide the optimization of reconstruction programs To evaluate track efficiency and systematics errors for different topological conditions ECC is the basic OPERA detector, but it is the only one escaping Monte-Carlo !

2. Jean Favier LAPP CERN Physics and soft meeting 23/04/04 THEN:The lack of data for various conditions ( particle type, angles, energies, fog densities, ambiant radioactivity integration times, etc) and poor statistics make difficult the reconstruction programs optimization. The large feed-back time between beam tests and scanning It was attracting to reproduce emulsions data by Monte-Carlo, as for the other detectors

3. Jean Favier LAPP CERN Physics and soft meeting 23/04/04 Genima GEN : GEANT3 generation of - single track (1 single field 200x200  2, double layer emulsion set-up) - or neutrino, showers events in a complete brick set-up. - The correct grain density is set by randomly eliminating some GEANT track hits to obtain the m.i.p density at : 32 IMA: single “classico” FORTRAN program: - read GEANT hits - add background fog - constructs the 32 images of grains, fog,etc present in the 2 emulsion layers NOW 128x128 pixels instead of 1024x1024 : factor 64 in computing time !!! -Artificial increase of depth of field to approximate reality - clusterises the images pixels NOW Digital Filter - finds micro-track NOW cut >= 8 hits to accept - finds base-track

4. Jean Favier LAPP CERN Physics and soft meeting 23/04/04 ccd plane Focused plane Grain plane d=3.254 mm d=200 mm r=6mm The systeme objective-ccd (in red) can move along the optical axis: we keep 16 tomographic planes ;  is defined by objective characteristics The virtual microscope  objective

5. Jean Favier LAPP CERN Physics and soft meeting 23/04/04 IMA : makes pictures For each “grain” x,y,z we calculate the intercepted surface by a conical prolongation, isolating the surface S of pixels to “dark”. The cone aperture is determined by the lense N.A (numerical aperture):  = arcsin(N.A/n refr ) Pixels are filled with grey in each of the 16 picture planes; grey density varies with 1 / S and e -d/ ( is an effective emulsion attenuation lenghth)

6. Jean Favier LAPP CERN Physics and soft meeting 23/04/04 Fog and background Fog is randomly generated as single grain with a density of 8 grains/ (10  ) 3 Album of real emulsions can be used also (radioactivity fossiles tracks)

7. Jean Favier LAPP CERN Physics and soft meeting 23/04/04 Emulsion simulation 16 images

8. Jean Favier LAPP CERN Physics and soft meeting 23/04/04 Emulsion simulation 16 images

9. Jean Favier LAPP CERN Physics and soft meeting 23/04/04

10. Emulsion simulation

11. Jean Favier LAPP CERN Physics and soft meeting 23/04/04 Emulsion simulation 16 images

12. Jean Favier LAPP CERN Physics and soft meeting 23/04/04 Emulsion simulation 16 images

13. Jean Favier LAPP CERN Physics and soft meeting 23/04/04 Emulsion simulation 16 images

14. Jean Favier LAPP CERN Physics and soft meeting 23/04/04 Emulsion simulation 16 images

15. Jean Favier LAPP CERN Physics and soft meeting 23/04/04 Emulsion simulation 16 images

16. Jean Favier LAPP CERN Physics and soft meeting 23/04/04 Emulsion simulation 16 images

17. Jean Favier LAPP CERN Physics and soft meeting 23/04/04 Emulsion simulation 16 images

18. Jean Favier LAPP CERN Physics and soft meeting 23/04/04 Emulsion simulation 16 images

19. Jean Favier LAPP CERN Physics and soft meeting 23/04/04 Emulsion simulation 16 images

20. Jean Favier LAPP CERN Physics and soft meeting 23/04/04 Emulsion simulation 16 images

21. Jean Favier LAPP CERN Physics and soft meeting 23/04/04 Emulsion simulation 16 images

22. Jean Favier LAPP CERN Physics and soft meeting 23/04/04 Emulsion simulation 16 images

23. Jean Favier LAPP CERN Physics and soft meeting 23/04/04 Performances of the European Scanning System Efficiency Efficiency is being estimated by European laboratories by using plates from a common test exposure 8 plates in contact were exposed to a  beam The brick was rotated in 14 different positions in order to test the angular dependency of efficiency

24. Jean Favier LAPP CERN Physics and soft meeting 23/04/04 Performances of the European Scanning System Purity Purity is being estimated by European laboratories measuring plates from a common reference batch with the same parameters used to measure efficiency Tracks found by the scanning system in a few cm2 are manually checked in order to evaluate the density of fake tracks Density of fake tracks is less than 1/cm2

25. Jean Favier LAPP CERN Physics and soft meeting 23/04/04 Performances of the European Scanning System Sy = 0 Sy = -0.180 Base-track Microtrack 6/7 plates 4 averages  cut Bkgnd = 1 fake/cm 2 Efficiency Salerno

26. Jean Favier LAPP CERN Physics and soft meeting 23/04/04 Offline cut:  < -6.667 + 0.4167PH Efficiency Napoli

27. Jean Favier LAPP CERN Physics and soft meeting 23/04/04 R&D Meeting, LNGS, 4th October 2004 Base-track efficiency Jun. 04 reference brick with lead sheets 18 – 25  = N6N6 N 5 + N 6 volume 1: sheets 20 – 25 volume 2: sheets 19 – 24 volume 3: sheets 18 – 23 6 samples of tracks ( external sheets only ) Bari

28. Jean Favier LAPP CERN Physics and soft meeting 23/04/04 Efficiency Neuchatel

29. Jean Favier LAPP CERN Physics and soft meeting 23/04/04 Volume tracks Base tracks efficiency vs peaks (averaged over 7 plates) Error bars = 1  spread of 7 plate efficiencies Red:  y 0 mrad Black:  y 200 mrad Bologna

30. Jean Favier LAPP CERN Physics and soft meeting 23/04/04 Scanning performance Basetracks MIC1 (SmartTracker6) Dry objective Bern

31. Jean Favier LAPP CERN Physics and soft meeting 23/04/04 Scanning performance Basetracks MIC2 (SmartTracker7) Dry objective Bern

32. Jean Favier LAPP CERN Physics and soft meeting 23/04/04 How fog can influence efficiency ? - Fog effects will be higher at large angle where the sensible volume around the track is higher -infection of a good cluster: the resulting barycentre becomes out of association: the hits number can go down from 6 to 5 - Deformations of good clusters by a fog one can produce a deterioration of qui2 -Oppositely, on a 5 hits track, one fog cluster can, by luck, occupy the sixth rank, so the track will be accepted

33. Jean Favier LAPP CERN Physics and soft meeting 23/04/04

34. Base-track efficiency Fog effect

35. Jean Favier LAPP CERN Physics and soft meeting 23/04/04

36. Grain density Fog=0 (preliminary) Nhit  6 Nhit  5

37. Jean Favier LAPP CERN Physics and soft meeting 23/04/04 Boliden Lead + Ca (NGL washed by Goslar) CERN refreshed emulsion (FD (6.3 + 0.5)g/(  m   ) Spider packing Delrin cover and side protection 35°C in the oven (1 year) FD (6.8 + 0.5)g/(10  m) 3 Long term test using PbCa (11/2004  11/2005) Track grains/100  m Emulsion sensitivity

38. Jean Favier LAPP CERN Physics and soft meeting 23/04/04 Distortion It is simulated by random rotation (0 to  max ) of the microtracks,leaving fixed the intercept with the basis; we varied  max from 0 to 40 mrad Emulsion layer 1basis

39. Jean Favier LAPP CERN Physics and soft meeting 23/04/04