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Why Monte-Carlo ?

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

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Why Monte-Carlo ?

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

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

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

  4. The virtual microscope Focused plane objective ccd plane d=3.254 mm Grain plane 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 Jean Favier LAPP CERN Physics and soft meeting 23/04/04

  5. 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/nrefr ) • 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) Jean Favier LAPP CERN Physics and soft meeting 23/04/04

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  23. 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 p beam The brick was rotated in 14 different positions in order to test the angular dependency of efficiency Jean Favier LAPP CERN Physics and soft meeting 23/04/04

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

  25. Performances of the European Scanning System Efficiency Microtrack Base-track 6/7 plates4 averagess cut Bkgnd = 1 fake/cm2 Sy = 0 Sy = -0.180 Salerno Jean Favier LAPP CERN Physics and soft meeting 23/04/04

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

  27. N6  = N5 +N6 Base-track efficiency Jun. 04 reference brick with lead sheets 18 – 25 volume 1: sheets 20 – 25 volume 2: sheets 19 – 24 volume 3: sheets 18 – 23 6 samples of tracks ( external sheets only ) Bari Jean Favier LAPP CERN Physics and soft meeting 23/04/04 R&D Meeting, LNGS, 4th October 2004

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

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

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

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

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

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

  34. Base-track efficiency Fog effect Jean Favier LAPP CERN Physics and soft meeting 23/04/04

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

  36. Nhit 5 Grain density Fog=0 (preliminary) Nhit 6 Jean Favier LAPP CERN Physics and soft meeting 23/04/04

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

  38. 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 1 basis Jean Favier LAPP CERN Physics and soft meeting 23/04/04

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

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

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

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

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

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

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

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