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  1. Tracking Algorithms Hervé Savajols & Thomas Roger (GANIL) Wolfgang Mittig (MSU) …

  2. Cubic Geometry

  3. MAYA : the movie

  4. ❍ For particle leaving MAYA at forward angles, identification is given by the energy loss in MAYA, energy deposit in Si and CsI wall ❍ For particle stopping inside MAYA, identification is given by the energy of the particle and its Range : He t t d p d p Range ∝ E2/MZ2 Maya identification ❍ Reconstruction of the reaction kinematics

  5. Event analysis Event display of pads signals. Each dot shows the pulse height of the pad Drift time distribution • - Selection of the particle in Si • Projected trajectectory • reconstruction • Theta2D and Range2D • - Vertex (target depth) • - Reaction plane angle ❍ Energy resolution ❍ Angular resolution Range resolution ≈ 1mm ∆θ ≈ ∆x/R (0.6 deg for R=10cm) ∆R/R ≈ 1mm/R (≈ 1% for Range = 10cm) ∆E/E = 0.5*1/R (≈ 0.5% for Range = 10cm)  Charge resolution ~ 10 %  Vertex resolution ~ 3 mm

  6. 11Li(p,t)9Li 3. Event output - Class LogFile - Class Eventouput - Class EventDisplay 1. Event Generator - Class Nuclei - Class Reactions - Class CrossSections - Class Event - Class EventOutput ∆E = 120keV 2. Detector - Class EnergyLoss - Class ActiveAreaGeometry - Class AncillaryDetector 4. OfflineAnalysis - Class Identification - Class ParicleTracking Hervé Savajols, GANIL Handy simulation software is necessary • Because of the energy loss in MAYA • Beam energy changes depending on the depth into MAYA • Energies detected in Si or CSI depend strongly on the reaction point. • Angular acceptance depend on the reaction point

  7. Hyperbolic secant squared method - principle - Induced charge distribution from a point source -> search of maxima along symetry axis

  8. Hyperbolic secant squared method - results - Calculated angle is shifted around 0° and 60° Extreme points has to be removed from the fitting procedure... -> Range has to be greater than 4 pads

  9. Global Fitting method Orthogonal distance regression Good resolution if only one track Problems if two or more tracks -> used for thin tracks. Range has to be greater than 3 pads

  10. Getting 3rd dimension Time from wires used to extract reaction plan10e angle -> angle < 60°

  11. Test of a complete algorithm - case of p(11Li,9Li)t reaction -

  12. Range measurement

  13. Geometry definition of the next active target Cylindrical geometry: symmetry around beam axis E // beam axis, uniform Projection on the endcap of the cylinder B // beam axis ASIC cards Pads Anode Cathode 50cm O 50cm Gangnant@ganil.fr Quantities to be measured: curvature radius, collected charge, range, angles For 0.5 mm position resolution, ΔE/E=2ΔR/R, expected energy resolution≈100 keV for θcm>20°

  14. K.Tyler & W.Mittig (MSU)