Preliminary Performance of the L2 Chamber (Side A) Michele Bianco, Maria Hoffmann, Givi Sekhniaidze, Joerg Wotschack, Weekly MicroMegas Meeting 05/02/2013

Overview Cosmic Stand Setup HV scan Side A / Side B comparison Pedestal calibration with different setup conditions 1/29/13

Cosmic Stand Data acquired by 16 APVs connected to SRS readout system (single FEC card), able to read out half chamber (Side B) Power supplied by five HV channels. Four used for the resistive strips, one for the drift electrode Gas flow monitored manually with gas flow-meter 1/29/13

Cosmic Stand L2 - Naming convension AR AL BR BL Trigger scheme Side A Scint. 1 Scint. 2 Scint. 3 MM L2 L2 side A L2 side B Three-fold coincidence Scheme 1: all three scintillators aligned along the strips AR AL BR BL Side A Side B LEFT Side RIGHT Side L2 - Naming convension 1/29/13

HV Scan Trigger scheme 1 used (as described in previous slides) HV on resistive strips scanned in the range 500 V – 580 V in steps of 10 Last two HV steps for side B (570 V – 580 V ) acquired two days later with different environmental conditions (different gas gain) At least 5k events collected at each step in side B At least 10K events collected at each step in side A 1/29/13

First cosmic signal from L2 chamber Side A 1/29/13

Cluster width vs. HV Side A Cluster width increases with HV as expected Cluster width quite large at HV 580 cluster width distributions average cluster width vs. HV cl_nclu == 1 cl_nclu == 1 1/29/13

Cluster width vs. HV Side B Cluster width increases with HV as expected Cluster width quite large at HV 580 Shift due to different environmental conditions cluster width distributions average cluster width vs. HV cl_nclu == 1 cl_nclu == 1 1/29/13

Pedestal calibration Different “Pedestal Calibration” have been studied: Different signal shaping time Different different chamber configurations (with/without external aluminium bar) honeycomb Drift panel Read-out panel APV25 Aluminium Bar 1/29/13

Pedestal calibration (different shaping time) Short Shaping time Long Shaping time 1/29/13

Pedestal calibration (Different chamber configurations) Short Shaping With external aluminium frame Without external aluminium frame 1/29/13

Pedestal calibration (Different chamber configurations) Long Shaping With external aluminium frame Without external aluminium frame 1/29/13

Summary L2 chamber Side A looks good as Side B Surface scan on Side A, still to be performed Dedicate test on pedestal calibration are ongoing Pedestal calibration without external aluminum frame looks more stable and flat as well long shaping time help w.r.t the short shaping time ……. 1/29/13