1. 27/02/2002M.D.P. - ATLAS Muon Week1 First results of Atlas RPC cosmic rays test Massimo Della Pietra Atlas RPC Group Napoli ( M. Alviggi, V. Canale, M. Caprio, G. Carlino, F. Conventi, R. de Asmundis, M.D.P., D. della Volpe, P. Iengo, S.Patricelli, L.Romano, G. Sekhniaidze )

2. 27/02/2002M.D.P. - ATLAS Muon Week2Outline RPC cosmic rays test in Naples. Definitions. Test results.  Gap currents and single rates  Full Plateau curves  Cluster size Conclusions.

3. 27/02/2002M.D.P. - ATLAS Muon Week3 RPC Test in Naples First chamber under test in Naples: BOS-B-004. final receivers 32  strips or 32  strips were tested with cosmic rays using final receivers. A complete scan of RPC performances with respect to HV and threshold values has been done.

4. 27/02/2002M.D.P. - ATLAS Muon Week4 Splitter board Shaper (50 ns) Latch Scaler TDC Shaper (50 ns) VME DAQ Setup Splitter board

5. 27/02/2002M.D.P. - ATLAS Muon Week5 Gap currents

6. 27/02/2002M.D.P. - ATLAS Muon Week6 Single rates

7. 27/02/2002M.D.P. - ATLAS Muon Week7 Single rates

8. 27/02/2002M.D.P. - ATLAS Muon Week8 Definitions (I) 10000 muons have been triggered for each run with fixed HV and threshold. golden To evaluate the RPC performances golden tracks were selected (1 single hit for each layer in drift chambers) reducing the sample to about 5000 events.

9. 27/02/2002M.D.P. - ATLAS Muon Week9 Definitions (II) Expected strip Expected area  The RPC is considered to be efficient if there is an hit in the “expected area” (defined as the expected strip  5 mm).

10. 27/02/2002M.D.P. - ATLAS Muon Week10 Definitions (III) Non physical cluster Physical cluster  We define Physical Cluster as the set of contiguous strips containing the expected one.

11. 27/02/2002M.D.P. - ATLAS Muon Week11 Plateau efficiency: ~ 96% Plateau efficiency: ~ 96% TDC e LATCH results are identical within 0,1 % TDC e LATCH results are identical within 0,1 % HV normalized HV normalized @ 1013 mbar, 20.5ºC  strips: Efficiency vs. HV

12. 27/02/2002M.D.P. - ATLAS Muon Week12  strips: Efficiency vs. Threshold Plateau efficiency: ~ 96% Plateau efficiency: ~ 96% TDC e LATCH results are identical within 0,1 % TDC e LATCH results are identical within 0,1 % HV normalized HV normalized @ 1013 mbar, 20.5ºC

13. 27/02/2002M.D.P. - ATLAS Muon Week13 Mean N. of Clusters  1.01 @ (0.71mV,10500 V) Mean N. of Clusters  1.01 @ (0.71mV,10500 V) HV normalized HV normalized @ 1013 mbar, 20.5ºC  strips: N. of Clusters

14. 27/02/2002M.D.P. - ATLAS Muon Week14 Phys. cluster size  1.3 @ (0.71mV,10500 V) Phys. cluster size  1.3 @ (0.71mV,10500 V) HV normalized HV normalized @ 1013 mbar, 20.5ºC  strips: Cluster size

15. 27/02/2002M.D.P. - ATLAS Muon Week15 Plateau efficiency: ~ 96% Plateau efficiency: ~ 96% TDC e LATCH results are identical within 0,1 % TDC e LATCH results are identical within 0,1 % HV not normalized! (DCS problem.) HV not normalized! (DCS problem.)  strips: Efficiency vs. HV

16. 27/02/2002M.D.P. - ATLAS Muon Week16 Plateau efficiency: ~ 96% Plateau efficiency: ~ 96% TDC e LATCH results are identical within 0,1 % TDC e LATCH results are identical within 0,1 % HV not normalized! (DCS problem.) HV not normalized! (DCS problem.)  strips: Efficiency vs. Threshold

17. 27/02/2002M.D.P. - ATLAS Muon Week17 Mean N. of Clusters  1.05 @ (0.59mV,10500 V) Mean N. of Clusters  1.05 @ (0.59mV,10500 V) HV not normalized! (DCS problem) HV not normalized! (DCS problem)  strips: N. of Clusters

18. 27/02/2002M.D.P. - ATLAS Muon Week18 Phys. cluster size  1.4 @ (0.59 mV,10500 V) Phys. cluster size  1.4 @ (0.59 mV,10500 V) HV not normalized! (DCS problem) HV not normalized! (DCS problem)  strips: Cluster size

19. 27/02/2002M.D.P. - ATLAS Muon Week19 Both curves reach 96% of efficiency Both curves reach 96% of efficiency HV not normalized to compare the two curves ! HV not normalized to compare the two curves !  and  Efficiency

20. 27/02/2002M.D.P. - ATLAS Muon Week20  and  Cluster size  strips are a little noisier than  strips (under investigation).  strips are a little noisier than  strips (under investigation). HV not normalized to compare the two curves ! HV not normalized to compare the two curves !

21. 27/02/2002M.D.P. - ATLAS Muon Week21Conclusions The results show a good RPC behavior for both  and  plane:  Efficiency  96 %  Cluster size 1.3 - 1.4 TDC and LATCH give identical results with shaped signals. The analysis tools to fully test up to 8 RPCs together are ready. We’re ready for massive tests. @ working point.