1. Atsuhiko Ochi, Yuki Edo, Yousuke Kataoka ATLAS MicroMEGAS meeting, 11/12/12

2.  Features ◦ Main board was manufactured (including screen printing) by industrial company (Laytech Inc.) ◦ Build up by bulk MM method. ◦ Resistive strips are formed by screen printing. ◦ Readout is connected to panasonic connector.  Dimensions ◦ Size : 10cm x 10cm effective area ◦ Readout : 1-Dimensional, 400um pitch ◦ Gas gap : ~ 100 um (estimated) ◦ Drift length : ~ 1.5cm ◦ Resistivity : ~ 100M  /cm 2012/12/11 A.Ochi Kobe Univ.2

3.  Gain measurements using 55Fe (5.9keV). ◦ Maximum gas gain ~ 10000 (using Ar:CO2 = 93:7) ◦ Operation voltage is 15% smaller than CERN MMs (T series, Z series)  Due to difference of amplification gap? 2012/12/11 A.Ochi Kobe Univ.3

4.  High rate capability test (8keV XG at CERN labo.) ◦ Small gain degradation are found in 10 7 counts/cm 2 irradiation (~ 10%) Histogram of qmax from APV25 2012/12/11 A.Ochi Kobe Univ.4

5.  Just now, we have a beam time for fast neutron at Kobe. ◦ I am participating this meeting from beam site.  We will put the same chamber in fast neutron beam, and test the properties under HIP circumstances (e.g. spark probabilities) 2012/12/11 A.Ochi Kobe Univ.5

6.  We will make a second prototype ◦ Printing method  Screen printing is good method, but engineer in industrial company suggests that, it will be easy to print large size pattern (with same accuracy) using dispenser.  We have a small dispenser system in KEK, and we will try to use this for next prototype. ◦ Resistive strip pattern  We should modify it like a zebra chamber, or some other pattern. ◦ Two dimensional readout. ◦ Variable drift space. 2012/12/11 A.Ochi Kobe Univ.6

7.  The Bulk MicroMEGAS prototype using screen printed resistive strips have been tested at Kobe RD51 labo and CERN H6 beamline.  The maximum gain with Ar-CO2 gas was 11000.  Results of beamtest will be given by Yousuke.  We will test the chamber under fast neutron just now!  Next prototype will be produced and tested at beginning of next year. ◦ Modifying the resistive value, printing pattern and printing method. ◦ Two dimensional readout. 2012/12/11 A.Ochi Kobe Univ.7