1. Micromegas-TPC Oct 2005 beam test in KEK Ar/isobutane 1T data Setting HMThreshold Analysis results of Run249-251(220V/cm) Analysis results of Run252-257(80V/cm),

2. Setting HMThreshold

3. Problems of Cluster finding How should it be solved? 1.Way of chage the Timewindow width 2.Way of change the HMthreshold 3.Way of chage the HMseachradius ・ Doublefit program recognizes the same signal to be another signals. I tried that I was solved by changing the HMthreshold. X Z

4. Setting HMThreshold HMThreshold10 HMThreshold6 Run 249 #41018 Bad! Good! Three hits are formed

5. Because the threshold is high, small signals are cut. HMThreshold10 HMThreshold6 HMThreshold10. Z X Z Z

6. A change of a event display by HMthreshold HMThreshold=10 HMThreshold=2 But, this event display is not so clean.

7. HMThresholdstop(0.5) HMThresholdstart(2.0) In this way I get possible to take many signals.

8. Event Display HMThresholdstart =2.0 HMThresholdstop = 0.5 Event display became clean!

9. Run249-251(220V/cm) Ar/isobutane 1T Pedestal 015

10. X resolution (220V/cm ） par HMThreshold HMThreshold=10 is the best resolution,but event numbers decrease,so I do not understand whether it is good resolution Number of 1track HMThreshold10 = 3710/4873 HMThreshold6 = 3837/4832 HMThreshold2 = 4005/4667

11. X resolution(220V/cm) HMThresholdstart =2.0 HMThresholdstop = 0.5 Neff=21 ～ 28(Magbolz=193)

12. Z resolution (220V) per HMThreshold Inversely, Z resolution improved so as to lower the threshold.

13. Z resolution(220V/cm) HMThresholdstart =2.0 HMThresholdstop = 0.5

14. Width of pad response(220V/cm) I did not understand whether Pad response data are right to use resistive foil, but show it for reference. Cd=193 Magboltz

15. Padresponse per row(220V/cm) Run 249-251

16. Padresponse Z dependence(220V/cm) Run 249-251

17. Phi direction (220V/cm) Run 249-251

18. Theta direction(220V/cm) Run 249-251

19. Run251-257(80V/cm) Ar/isobutane 1T Pedestal 017

20. X resolution (80V/cm) HMThresholdstart =2.0 HMThresholdstop = 0.5 Neff=39 ～ 23(Magboltz=127) Run 252-257

21. Z resolution (80V/cm) HMThresholdstart =2.0 HMThresholdstop = 0.5

22. Width of pad response (80V/cm) HMThresholdstart =2.0 HMThresholdstop = 0.5 Cd=127 Magboltz Run 252-257

23. Phi direction(80V/cm) HMThresholdstart =2.0 HMThresholdstop = 0.5 Run 252-257

24. Theta direction(80V/cm) HMThresholdstart =2.0 HMThresholdstop = 0.5 Run 252-257

25. Conclusion It was possible to solve the problem of cluster finding by lowering HMthreshold. Future works ・ I analyze Bias and want to correct resolution in pad neighborhood. V fc 220 V/cm 80 V/cm Ｄ (Magboltz) 176 ±3.64 (193) 132 ±10.4 (127) σ ＰＲ０ 1543 ±5.92 1563 ±17.2 Ｄ /√ Ｎｅ ｆｆ 41.6 ±4.94 20.2 ±5.97 σ ｘ０ 163 ±17.6 167 ±9.93 Ｎｅｆｆ 21 ～ 2839 ～ 23