31 March 2004 Geneva University MICE TPG Reconstruction Cluster finding Space point reconstruction Track recognition Track fit GENEVA UNIVERSITY GENEVA UNIVERSITY 31 March 2004 Voloshyn Olena

31 March 2004 Geneva University status end of march: I Cluster finding written, to be tested, (promised end of march) II Space point reconstruction : almost finished, missing implemetation of errors on space points III Track recognition (exists in HARP code, and in G4MICE for SciFi) (exists in HARP code, and in G4MICE for SciFi) IV Track fit (exists in HARP code and in G4MICE for SciFi) (exists in HARP code and in G4MICE for SciFi) all promised for end of May.

31 March 2004 Geneva University Cluster finding Cluster algorithm takes as input the digitized hits. Different digits belong to the same cluster if they are neighbourgs in strip number and if their signals overlap or are close in time. Dimension of cluster is defined by lower and upper strip number. Cluster position is obtained as the centre of gravity of the digits that belong to this cluster weighted by their amplitudes. Amplitude of cluster is given as the sum of the amplitudes of the digits associated with this cluster.

31 March 2004 Geneva University Space Point definition Crossing of the clusters close in time gives the space point position in plane x-y. z coordinate of space point is defined z=v dr * t dr z=v dr * t dr U X V U X V

31 March 2004 Geneva University Track recognition Pattern recognition algoritm groups the space point recognized as belonding to the same track and searches the following point in the volume of a truncated cone with the axis defined by the previous points. The parameters of the cone will be optimised for 200 MeV track. The parameters of the cone will be optimised for 200 MeV track. Forward acceptance a Radius.....

31 March 2004 Geneva University Track fit Fit is performed in two steps: - circular fit in the x-y plane that alows to determine the inverse of the radius of curvature , the impact parameter in the x-y plane d 0 and the angle between the projection on this plane of the particle momentum at the impact point and the X axis   ; - Linear fit in the Sxy-Z plane that alows to determine the tangent of the dip angle and the Z o coordinate at the impact point. y x z Sxy Zo do p Oo tg a

31 March 2004 Geneva University (at a later stage) the calculated helix parameters will be used as a seed for a futher Kalman fit which handles multiple scattering and energy loss. The energy loss (which is derived from amplitude) and momentum (as derived from curvature and phase advance) will be estimated.