1. 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

2. 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

3. 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

4. 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

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

6. 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

7. 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

8. 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

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

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

11. 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

12. 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

13. 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

14. 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

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