Résumé du preprint Irfu-09-121

Measurements of Lorentz angles with a Micromegas detector in high transverse magnetic fields
P. Konczykowski, S. Aune, J. Ball, S. Cazaux, E. Delagnes, M. El Yakoubi, C. Lahonde-Hamdoun, S. Lhenoret, O. Meunier, A. Mohamed, S. Procureur, F. Sabatié
We measured the Lorentz angles in an Argon +10% isobutane mixture using a Micromegas detector placed inside the CLAS-DVCS solenoid of Hall B at the Jefferson Laboratory. The primary goal of these tests was to validate Magboltz based simulations developed for the implementation of Micromegas bulk detectors in the Central Tracker of the future CLAS12 spectrometer. We used a UV Laser to extract electrons from the drift electrode of the detector. After amplification, the signal was collected on the readout strips. The difference of position observed between runs with and without magnetic field provided a direct measurement of the Lorentz angle. Scans in the drift electric field were performed for the first time in very high magnetic fields, up to 4.2 T, and a good agreement was observed with the Magboltz predictions.