240 likes | 254 Views
Characterization of Micromegas resistive detectors for the MAMMA project. D. Attié, P. Colas, E. Ferrer-Ribas, A. Giganon, I. Giomataris, F. Jeanneau, P. Shune, M. Titov, W. Wang, S. Wu. Within the MAMMA collaboration Arizona, Athens (U, NTU, Demokritos ), BrookhaVen ,
E N D
Characterization of Micromegasresistive detectors for the MAMMA project D. Attié, P. Colas, E. Ferrer-Ribas, A. Giganon, I. Giomataris, F. Jeanneau, P. Shune, M. Titov, W. Wang, S. Wu Within the MAMMA collaboration Arizona, Athens(U, NTU, Demokritos), BrookhaVen, CERN, Harvard, Istanbul, Naples, CEA Saclay, Seattle, USTC Hefei, South Carolina, St. Petersburg, Shandong, Stony Brook, Thessaloniki RD51 Collaboration Meeting - Bari October 8th, 2010 WP meeting 94
Overview • The MAMMA project: Muon Atlas MicroMegasActiVity (J. Wotschack) • The Saclay beam test in 2009 at Cern: • Resistive detector efficiency in high intensity beam • Preliminary results • Next beam test preparation and resistive bulk characterization • Gain measurement • Stability in time • Spark topology of the resistive detectors • Conclusion RD51 Collaboration Meeting, Bari ̶ October 8th, 2010
The MAMMA Project LsLHC = 10 × LLHC = 1035 cm2.s-1 • Increase of the neutron, photon and hadron background • Replacement or upgrade of the muon forward chambers • Requirements: • High rate capability (≤ 10 kHz.cm-2) • Spatial resolution ~100 µm (θ ≤ 45 °) • Radiation hardness and good ageing properties • Time resolution ~few ns • Level1 triggering capability • Large surface • MPGD: Bulk Micromegas • Fast and efficient ion collection • TPC mode possible: sensitivity to incidence angle. • « bulk » production process suitable for large surfaces • Resistive coating may solve the sparking issue RD51 Collaboration Meeting, Bari ̶ October 8th, 2010
The Saclay beam test setup at CERN (2009) Detectors in test Resistive Non-Resistive Beam 1 mm 0.25 mm 1 mm X X Y X Y • Aim: test different resistive film detectors and compare behaviour to non-resistive detectors in order to operate in high rate • Telescope: 3 X-Y detectors (10 10 cm2) • Electronics: GASSIPLEX • DAQ: realised by Demokritos • Gas: 95%Ar + 3% CF4 + 2% isobutane • Tested detectors: • - Standard bulk detectors • - Resistive coating detectors • - Segmented mesh detector 120 GeV π+ SPS-H6 Y RD51 Collaboration Meeting, Bari ̶ October 8th, 2010
Current and voltage behaviourat 10 KHz/cm² Standard bulk (SLHC2: 2mm) Resistive strip bulk (R6: 1mm, 400kΩ/□) SLHC2: HV=400V (Gain ~3000): - current when sparking < 0.4 mA -voltage drop< 5% R6: HV=390V (Gain ~3000): - current when sparking < 0.08 mA -voltage drop<0.5% Ar /CF4/Iso (95/3/2) RD51 Collaboration Meeting, Bari ̶ October 8th, 2010
Summary of the 2009 beam test (Gain~3000) R3 R5 R6 S1 RD51 Collaboration Meeting, Bari ̶ October 8th, 2010
Spatial resolution • δ: define by residuals of the cluster position and extrapolated track from telescope: • δMM:convolution of: - the intrinsic Micromegas resolution - the track resolution (extrapolated) ~68µm R6(1mm pitch, 400kΩ/□) R3(2mm pitch, 2MΩ/□) δ=105µm δMM= 80µm δ=241µm δMM= 231µm RD51 Collaboration Meeting, Bari ̶ October 8th, 2010
Cluster size Resistive detectors: Standard detector: Ar /CF4/Iso (95/3/2) RD51 Collaboration Meeting, Bari ̶ October 8th, 2010
Track position With hit in the tested detector Without hit in the tested detector Inefficiency due to pillars and misalignment RD51 Collaboration Meeting, Bari ̶ October 8th, 2010
Set-up for the next test beam at Cern • New telescope: 3 X-Y detectors(10 x 10 cm2) smaller pitch built in Saclay bulk workshop • Electronics: GASSIPLEX (96 channels per detector) • DAQ: more recent computer recording the spark counting and beam trigger • Gas: 98%Ar + 2% isobutane • Trigger improvement: PMs as close as possible to the telescope • New detectors to be tested: (built at Cern by Rui) Detectors to be tested Resistive Resistive Resistive Resistive 0.5 mm 0.25 mm 0.5 mm X Y X Y X Y X Y X Y RD51 Collaboration Meeting, Bari ̶ October 8th, 2010
Gain cures in Ar/Isobutane 2% Ar/Iso (98/2) RD51 Collaboration Meeting, Bari ̶ October 8th, 2010
Signal evolution in time for resistive detectors Ar/Iso (98/2) RD51 Collaboration Meeting, Bari ̶ October 8th, 2010
Normalized signal evolution of the resistive detectors Ar/Iso (98/2) RD51 Collaboration Meeting, Bari ̶ October 8th, 2010
Detector characteristics summary in Ar/C4H10 (97:2) RD51 Collaboration Meeting, Bari ̶ October 8th, 2010
Simple model RD51 Collaboration Meeting, Bari ̶ October 8th, 2010
Sparkstudy • Measurement through a 1 MΩ resistor • Detector divide in four parts • Sparks triggered by source (241Am) • HVdrift= -450V (5 mm gap) • HVmesh up to sparks arising • Threshold = 1V 1OO mm 23 strips 23 strips 23 strips 23 strips 1OO mm 1MΩ Oscilloscope Channel 4 Channel 3 Channel 2 Channel 1 RD51 Collaboration Meeting, Bari ̶ October 8th, 2010
Standard bulk Trigger on Channel 2 Vmesh = 330V RD51 Collaboration Meeting, Bari ̶ October 8th, 2010
ResistiveKapton 2 MΩ/□ Vmesh = 380V Trigger on Channel 3 Connector issue on channel 4 RD51 Collaboration Meeting, Bari ̶ October 8th, 2010
Spark behaviour in resistive detectors • Trigger on Channel 2 • Vmesh = 340V R17, Joerg like R14, Resistive strips 300 kΩ/□ RD51 Collaboration Meeting, Bari ̶ October 8th, 2010
Charge seen by the strips • G380V ~ 2 G360V • Q380V~ 1.2 Q360V • Trigger on Channel 2 • Vmesh = 340V & Vmesh = 360V R17, Joerg like R14, Resistive strips 300 kΩ/□ RD51 Collaboration Meeting, Bari ̶ October 8th, 2010
Spark topology of resistive detectors • Resistive strip detector has similar spark signal (exponential) than non-resistive detector but with an attenuation about 30 % and similar time constant (=RC) • Carbon-Loaded Kapton and Joerg-like detectors have shaping-like signals but the Joerg-like detector signal are shorter and ten times smaller • Signal from CLK are seen on the adjacent pads. RD51 Collaboration Meeting, Bari ̶ October 8th, 2010
Conclusions • It is still to soon to say that a resistive coating could solve the spark from operation. • In some configuration the resistive coating is able to contain or even suppress the spark signal. • We are now ready for the next beam test at Cern to determine in high rate condition operation the efficiency of the various resistive Micromegas. • After the choice of a technology spark proof, other stages are to come, ageing studies, larger surface, etc… RD51 Collaboration Meeting, Bari ̶ October 8th, 2010
Garfield simulation for Argon/Isobutane gas mixture RD51 Collaboration Meeting, Bari ̶ October 8th, 2010