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New results from CLAS12 forward resistive Micromegas produced by CIREA/ELVIA and CERN . Gabriel CHARLES. New results from CLAS12 forward resistive Micromegas built by ELVIA and CERN. Collaboration with ELVIA Geometry of the detector and first measurements
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New results from CLAS12 forward resistive Micromegas produced by CIREA/ELVIA and CERN Gabriel CHARLES
New results from CLAS12 forward resistive Micromegas built by ELVIA and CERN Collaboration with ELVIA Geometry of the detector and first measurements Tests with a cosmicbench Conclusions G. Charles Workshop RD51, 24/04/2013 0
Micromegas production at CIREA Conclusion slide by D. Neyret for the previous RD51 mini-week G. Charles Workshop RD51, 24/04/2013 1
ForwardMicromegas for CLAS12 Gerber view • Specifications : • active area : 430 mm diameterdiskwith a 50 mm diameterholeat the center • PCB thicknesslessthan 100 µm and glued on ROHACELL • 500 µm pitch, with 100 µm betweentwostrips • resistivestripsà la Joerg Central zone Two prototypes tested Prototype by CERN Prototype by CIREA G. Charles Workshop RD51, 24/04/2013 2
Stripresistivity for the CERN prototype The resistivitywasmeasuredin more than 400 points on a non-bulked PCB Strip 0 strip Strip 290 Ground Strip 960 Courtesy: D. Attié G. Charles Workshop RD51, 24/04/2013 3
Cosmic test bench • The twoforward prototypes have been tested • For both, more than 500,000 triggers have been recorded • For each trigger, when a cluster isreconstructed in all the reference detectors, the trackisinterpolated to the prototype • The position interpolatedisthencompared to the cluster reconstructed in the detector under test G. Charles Workshop RD51, 24/04/2013 4
First tests • No leakagecurrentafter one day • Excellent S/N ratio • Other variables consistent with standard Micromegas <S/N> ~ 140 atVmesh = 450 V <S/N> ~ 150 atVmesh = 460 V G. Charles Workshop RD51, 24/04/2013 5
Efficiencies Prototype by ELVIA • Central zone not connected (forgethole in the drift) • Lowerefficiency on the top left part of the detector Prototype by CERN • Excellent efficiency on almost all the detector • Lowefficiency on the top left part of the detector G. Charles Workshop RD51, 24/04/2013 6
Efficiencies Prototype by ELVIA • Central zone not connected (forgethole in the drift) • Lowerefficiency on the top left part of the detector • Efficiencyaround 90% Prototype by CERN • Excellent efficiency on almost all the detector • Lowefficiency on the top left part of the detector • Efficiencybetterthan 90% almosteverywhere G. Charles Workshop RD51, 24/04/2013 6b
Gain ELVIA CERN Samefields for both detectors Amplification gaps are different. ! • The two detectors have lower gain bothat the same position • Just a coincidence ? A gasleak ? Switch gas entrance and exit to check • About gas circulation : the design willbesoonfinalized, simulations by finiteelements are ongoing G. Charles Workshop RD51, 24/04/2013 7
Tests under X-ray generator Courtesy: C. Lahonde-Hamdoun and S. Procureur Preliminary conclusion : thereis no saturation at 1 MHz per cm². G. Charles Workshop RD51, 24/04/2013 8
Conclusions and perspectives • Large size resistive MM by CIREA • Production withoutproblem • Prototype tested in cosmicbench and under X rays • Normal behaviorundercosmic rays : no leakagecurrent • First results on performances • Very good efficiency • No sign of saturation yetwith X-rays • Next CLAS12 resistivemay have lowerresistivity • Nextstepswith ELVIA • Test of forward prototypes of resistive MM made by serigraphy by ELVIA • Test of small (6x10 cm² active area) prototypes withburiedresistors for COMPASS • Large size (40x40 cm²) non-simplified prototype for COMPASS 500 µm G. Charles Workshop RD51, 24/04/2013 9