ACTAR meeting - Dec 10th 2008Hervé Savajols (GANIL) Tracking Algorithms Hervé Savajols & Thomas Roger (GANIL) Wolfgang Mittig (MSU) …

ACTAR meeting - Dec 10th 2008Hervé Savajols (GANIL) Cubic Geometry

ACTAR meeting - Dec 10th 2008Hervé Savajols (GANIL) MAYA : the movie

ACTAR meeting - Dec 10th 2008Hervé Savajols (GANIL) 4 ❍ For particle leaving MAYA at forward angles, identification is given by the energy loss in MAYA, energy deposit in Si and CsI wall d p t He pd t ❍ Reconstruction of the reaction kinematics ❍ For particle stopping inside MAYA, identification is given by the energy of the particle and its Range : Range ∝ E 2 /MZ 2 Maya identification

ACTAR meeting - Dec 10th 2008Hervé Savajols (GANIL) 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 Event analysis Event analysis ❍ 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

ACTAR meeting - Dec 10th 2008Hervé Savajols (GANIL) 6 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 1. Event Generator - Class Nuclei - Class Reactions - Class CrossSections - Class Event - Class EventOutput 2. Detector - Class EnergyLoss - Class ActiveAreaGeometry - Class AncillaryDetector 4. OfflineAnalysis - Class Identification - Class ParicleTracking Hervé Savajols, GANIL 3. Event output - Class LogFile - Class Eventouput - Class EventDisplay 11 Li(p,t) 9 L i ∆ E = 120keV

ACTAR meeting - Dec 10th 2008Hervé Savajols (GANIL) Hyperbolic secant squared method - principle - Induced charge distribution from a point source -> search of maxima along symetry axis

ACTAR meeting - Dec 10th 2008Hervé Savajols (GANIL) 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

ACTAR meeting - Dec 10th 2008Hervé Savajols (GANIL) 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

ACTAR meeting - Dec 10th 2008Hervé Savajols (GANIL) Getting 3 rd dimension Time from wires used to extract reaction plan10e angle -> angle < 60°

ACTAR meeting - Dec 10th 2008Hervé Savajols (GANIL) Test of a complete algorithm - case of p( 11 Li, 9 Li)t reaction -

ACTAR meeting - Dec 10th 2008Hervé Savajols (GANIL) Range measurement

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ACTAR meeting - Dec 10th 2008Hervé Savajols (GANIL) 16 Geometry definition of the next active target 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 Anode Pads ASIC cards Cathode O 50cm 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  cm >20° 50cm

ACTAR meeting - Dec 10th 2008Hervé Savajols (GANIL) 17 K.Tyler & W.Mittig (MSU)

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