Darmstadt 2008 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 34: Postersitzung

HK 34.35: Poster

Donnerstag, 13. März 2008, 14:00–16:00, Poster C3

New HADES Alignment Strategy with Millepede^* — •Olga Pechenova and Vladimir Pechenov for the HADES collaboration — II Physikalisches Institut. Univ. Giessen

The feasibility and the results of applying internal and global alignment methods of the HADES MDC chambers are discussed. These methods are based on a simultaneous fit of track and alignment parameters using the Millepede approach (http://www.desy.de/∼blobel). Millepede solves the linear least square problem for the alignment parameters. Different types of data were used simultaneously to align the MDC chambers (data from different beamtimes, beam and cosmic data). The method was tested with simulated data as well as with real data taken in various beamtimes between 2005 and 2007. 426 alignment parameters were obtained simultaneously. The influence of misalignment on the reconstruction of individual tracks and pairs from elastic scattering has been estimated. First results show that the quantity and the quality of fitted individual tracks and of pairs from elastic scattering were improved significantly.

^*This work was supplied in part by GSI and BMBF (6GI179)