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

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

3. 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
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4. 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
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5. 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
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6. First cosmic signal from L2 chamber Side A
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7. 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
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8. 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
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9. 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
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10. Pedestal calibration (different shaping time)
Short Shaping time
Long Shaping time
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11. Pedestal calibration (Different chamber configurations)
Short Shaping
With external aluminium frame
Without external aluminium frame
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12. Pedestal calibration (Different chamber configurations)
Long Shaping
With external aluminium frame
Without external aluminium frame
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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