a TPC with resistive Micromegas Recent results from a TPC with resistive Micromegas D. Attié, P. Colas, M. Dixit, M. Riallot, Yun-Ha Shin, S. Turnbull, W. Wang 25/05/2010 Wenxin Wang-5th RD51 Collaboration meeting 1

Large Micromegas TPC Prototype for ILC One module was installed in the centre of the large TPC each time 25/05/2010 Wenxin Wang-5th RD51 Collaboration meeting

Detector Modules 2 Resistive Kapton Resistive Kapton Standard Resistive ink ~2(?) MΩ/□ Resistive Kapton ~5 MΩ/□ Standard 2 Resistive Kapton ~3 MΩ/□ 25/05/2010 Wenxin Wang-5th RD51 Collaboration meeting

PRF(Pad Response Functions) fits, z ~ 5 cm Preliminary Data Analysis Results ( B=1T ) Γ ~ 2.6 mm Γ ~ 4 mm δ ~ 10 mm δ ~ 14 mm B=1T data : comparison of resistive ink and Carbon-loaded Kapton PRF(Pad Response Functions) fits, z ~ 5 cm 25/05/2010 Wenxin Wang-5th RD51 Collaboration meeting

Preliminary Data Analysis Results ( B=1T ) Position residuals xrow-xtrack 25/05/2010 Wenxin Wang-5th RD51 Collaboration meeting

Preliminary Data Analysis Results ( B=1T ) Mean Residual vs Row Number Z-independent distortions Distortions up to 50 microns for resistive paint (blue points) Rms 7 microns for CLK film (red points) Z=5cm Z=35cm Z=50cm 25/05/2010 Wenxin Wang-5th RD51 Collaboration meeting

Preliminary Data Analysis Results ( B=1T ) Module_CLK Module_INK Resolution as a function of drift distance 25/05/2010 Wenxin Wang-5th RD51 Collaboration meeting

Dependence of resolution with data taking conditions Preliminary Data Analysis Results ( B=1T ) Resolution at z=5cm (µm) Vmesh (V) Dependence of resolution with data taking conditions 25/05/2010 Wenxin Wang-5th RD51 Collaboration meeting

Drift velocity measurements ( B=0T ) Vdrift = 7.698 +- 0.040 cm/µs at E=230 V/cm (Magboltz : 7.583+-0.025(gas comp.)) The difference is 1.5+-0.6 % 25/05/2010 Wenxin Wang-5th RD51 Collaboration meeting

Drift velocity measurements ( B=0T ) Drift Velocity in T2K gas compared with Magboltz simulations for - P=1035 hPa, - T=19°C - 35 ppm H20 25/05/2010 Wenxin Wang-5th RD51 Collaboration meeting

Preliminary Data Analysis Results (B=0T) Module_4 Module_5 Resolution as a function of drift distance 25/05/2010 Wenxin Wang-5th RD51 Collaboration meeting

Neff is stable with cuts Magnetic field Peaking time Resolution Neff Module_4 resistive Kapton of ~ 3 MΩ/□ B=0T (December 2009) 200ns 56 μm 38.3 Module_5 61 μm 39 Module_CLK resistive Kapton of ~ 5 MΩ/□ B=1T (March 2010) 500ns 53 μm 42.5 Module_INK resistive ink of ~ 2(?) MΩ/□ 100 μm 43.8 Expected : Neff = 47.7 * <G>2 / <G2> . Leads to (too?) high values of q Maybe information from neighbouring rows increases artificially Neff, but this would introduce a correlation between neighbouring rows : not observed (skipping 2 lines every 3 does not change Neff measurement) Neff is stable with cuts At B=1 T, uncertainties from B (assumed to be 0.98 T) and CD 25/05/2010 Wenxin Wang-5th RD51 Collaboration meeting

New T2K Electronics NEW ELECTRONICS – FLAT ON THE BACK OF THE MODULE Goal: Fully equip 7 modules with more integrated electronics, still based on the T2K AFTER chip. First prototype in June 2010 Tests at fall 2010 Then production and characterization of 9 modules in 2011 at the CERN T2K clean room 25/05/2010 Wenxin Wang-5th RD51 Collaboration meeting

Conclusions and outlook Since December 2008, 5 modules of Micromegas TPC have been measured and good results were obtained. The resistive CLK is more uniform than resistive ink. Resolution at z=0: 50 times smaller than the pad size. Quantitative measurement of Neff. Next step: 7 modules to fully equip the present endplate. 25/05/2010 Wenxin Wang-5th RD51 Collaboration meeting

Thank you 25/05/2010 Wenxin Wang-5th RD51 Collaboration meeting