Hybrid MPGD based photon detector, R&D update. RD51 WG1 SL on behalf of Trieste THGEM group Detector performance in CH4 rich mixtures. Maximum gain stability region with 55Fe source. Operations in pure CH4. Large prototype performance

Hybrid detector FIRST SMALL SIZE PROTOTYPE UV LED Source 5 mm 55Fe X–Ray Source. Drift wires THGEM Micro Mesh Anode UV LED Source Kapton/Fused Silica Window Bulk Micromegas: courtesy of Saclay COMPASS colleagues FIRST SMALL SIZE PROTOTYPE 15 mm 5 mm MICROMEGAS stage 128 mm bulk Preliminary test Ar:CO2 70:30. CAEN N471A High Voltage PSU Cremat CR – 110/110 Canberra Spectroscopy amplifier Amptek MCA 8000A

Factor 10 for 250V of ∆V. Factor 10 for 100V of VMesh Effective GAIN vs. Transfer Field GAIN vs. ∆V and VMesh 0.4-0.8-0.4 THGEM Transfer field is not critical. Almost no effect above 0.8 kV/cm Factor 10 for 250V of ∆V. Factor 10 for 100V of VMesh

Full scan with different CH4 % Maximum GAIN ~ 2.4 X 105 S Levorato. Rd51 Collaboration Meeting, CERN Feb-2014

Full scan with different CH4 % Plateau represents the unitary THGEM gain, corresponding MM GAIN ~ 500. S Levorato. Rd51 Collaboration Meeting, CERN Feb-2014

Full scan with different CH4 % 55Fe source (~220 primary) The maximum stable gain is typically between 2·105 and 3·105 Total charge > 5·107, close to the Raether limit S Levorato. Rd51 Collaboration Meeting, CERN Feb-2014

Ar:CH4 10:90, (Fe55 X-Ray Source ) S Levorato. Rd51 Collaboration Meeting, CERN Feb-2014 Factor 10 for 100V of VMesh

Exploring the stability region (∆Vand Vmesh) THGEM | V_MESH > Volts DEL_V [V] 610 620 630 640 650 660 670 680 1760 17117 34179 42477 52879 45000 60175 74334 91021 1780   44581 52631 62043 57141 88493 108720 1800 54365 54107 61186 74333 86470 108214 135015 1820 59318 66242 92507 90344 113271 130969 171929 1840 74798 77437 94055 117822 160804 1860 54613 89306 103663 117306 139060 169906 1880 69783 110742 147151 170412 1900 83436 136026 154230 180525 222496 1920 167378 189157 239075 Ar:CH4 30:70. Effective GAIN are in 103 The previous ∆V scan was done in this region Numbers are in black are for fully stable region Numbers are in red are regions where we have experienced trips. S Levorato. Rd51 Collaboration Meeting, CERN Feb-2014

Exploring a larger region (∆V and Vmesh) THGEM | V_MESH > Volts DEL_V [V] 600 610 620 630 640 650 660 670 680 690 700 710 1720   95.6 1740 Effective GAIN are in 10^3 88 114.3 1760 86.5 102.8 1780 80.9 105.7 137.5 1800 90 101.1 130.5 1820 91 107.2 137 160.8 1840 83.9 113.3 133.5 163.3 1860 87.1 105.2 134 166.9 1880 89.9 91.5 106.7 131.5 174.5 1900 72.8 100.1 118.8 166.4 1920 69.8 128.4 144.1 168.9 176.5 1940 115.8 164.3 187.1 214.9 1960 151.2 Numbers are in black are for fully stable region Numbers are in red are regions where we have experienced trips. S Levorato. Rd51 Collaboration Meeting, CERN Feb-2014

The calculated GAIN sharing between THGEM and MM S Levorato. Rd51 Collaboration Meeting, CERN Feb-2014

Towards large size prototypes S Levorato. Rd51 Collaboration Meeting, CERN Feb-2014

The 300 X 300 mm2 Micro Mesh setup Drift Wires 13 mm Micro Mesh (prepared by Rui in CERN by BULK technology) Anode S Levorato. Rd51 Collaboration Meeting, CERN Feb-2014

The Hybrid scheme MicroMegas detector and THGEM, medium size preparation Medium size prototype MESH size 300x300 mm2 THGEM strips using a resistive ink of 100kW/ Confirm the same performances on Medium size prototype Problematic: Anode planarity <->Mesh to anode distance Bulk MicroMegas technology S Levorato. Rd51 Collaboration Meeting, CERN Feb-2014

Setup Details 123456 A B C D E F The 300 X 300 mm2 Anode has been divided in 36 sectors. Each Sectors contains 16 pads. We connect one sector to CREMAT, all others remain connected to 50Ω terminators. We use one HV channel to Power six drift Sectors with Splitters We use CAEN N471A HV PS. Normal readout chain as mentioned before for 30 X 30 mm2 Prototype. S Levorato. Rd51 Collaboration Meeting, CERN Feb-2014

The Hybrid scheme MicroMegas detector and THGEM, medium size preparation Pure MicroMegas detector Same readout scheme as before Ar/CO2 70-30 strips using a resistive ink of 100kW/ S Levorato. Rd51 Collaboration Meeting, CERN Feb-2014

Choosing THGEM(300 X 300 mm2) for the Hybrid We tried to chose a 300 X 300mm2 THGEM for combining with the Mesh to prepare our 300 X 300 mm2 prototype. We started from PCB Selection 2% thickness variation Paschen Method to evaluate the quality Applied our polishing procedure Paschen Method to evaluate the procedure effect 1 2 3 4 5 6 S Levorato. Rd51 Collaboration Meeting, CERN Feb-2014

Choosing THGEM(300 X 300 mm2) for the Hybrid Then we test them in Single to obtain Gain Uniformity. #72 Date Sec 1 Sec 2 Sec 3 Sec 4 Sec 5 Sec 6 Before treatment 57 59 58 56 60 After treatment 92 97 100 101 102 90 #73 Date Sec 1 Sec 2 Sec 3 Sec 4 Sec 5 Sec 6 Before treatment 62 63 64 After treatment 95 92 100 102 98 97 #74 Date Sec 1 Sec 2 Sec 3 Sec 4 Sec 5 Sec 6 Before treatment 60 56 55 58 61 52 After Treatment 84 88 77 75 90 92 S Levorato. Rd51 Collaboration Meeting, CERN Feb-2014 N.B. All the values are in %

The Hybrid scheme MicroMegas detector and THGEM, medium size preparation THGEM 300x300 mm2 Segmented into 6 independent sectors Pure THGEM Same readout scheme as before Ar/CO2 70-30 Raw PCB material after selection For thickness uniformity Units in microns Detector Gain at the same DV for all the sectors 1450 V strips using a resistive ink of 100kW/ S Levorato. Rd51 Collaboration Meeting, CERN Feb-2014

The full hybrid test All the THGEM Bottom sectors together with one HV channel. Drift Sectors together with another HV channel. We used resistive coupling for all THGEM top sectors separately. For all channels we use CAEN N471A HV PS. S Levorato. Rd51 Collaboration Meeting, CERN Feb-2014

Result S Levorato. Rd51 Collaboration Meeting, CERN Feb-2014

Result S Levorato. Rd51 Collaboration Meeting, CERN Feb-2014

Very promising result from the “hybrid architecture” (medium size) Can be operated in pure CH4 mixtures without performance loss ( higher V) Mesh (alone) gain uniformity good! THGEM pre-selection procedure and polishing process confirm their validity Satisfactory result from the THGEM combined to Mmegas! Next steps: enlarge the size of the B-MMegas 300x600 FE electronic protection under study ? A la resistive anode ? Goal: Have a detector 300x600 ready for the next TBeam (Sep-Oct 2014) THANK YOU S Levorato. Rd51 Collaboration Meeting, CERN Feb-2014

Setup for simultaneous use of UV LED and 55Fe source The measured gain is the same for the same conditions while using UVLED and 55Fe sources simultaneously S Levorato. Rd51 Collaboration Meeting, CERN Feb-2014

UV LED and 55Fe provide compatible results S Levorato. Rd51 Collaboration Meeting, CERN Feb-2014

Some calculation regarding Calculating the Mesh and THGEM gain separately We know the formula for calculating Gain of a Gaseous Detector is given by: 𝐺 𝑑𝑒𝑡 = 𝐴𝑒 𝛼 ∆𝑉− 𝑉 𝑐 / 𝑉 10 Where A and 𝛼 are the constants. ∆𝑉 is the voltage difference across the detector electrodes. 𝑉 𝑐 is the Critical Voltage at which it has a gain of 1. And 𝑉 10 is the voltage required to increase the gain by factor 10. For our case we find out that for THGEM it is 𝑉 𝑐 =1220𝑉, 𝑉 10 =108𝑉 and for Micromegas it is 𝑉 𝑐 =362𝑉, 𝑉 10 =50.4𝑉 for the gas mixture Ar:CH4 30:70 And we calculate the gain for each box for the previous plot ignoring 𝐴 𝑎𝑛𝑑 𝛼, because the correction is negligible . We marked the boxes which are the nearest to the last stable gain achieved. Also the boxes marked in red are the gains which are completely unstable. S Levorato. Rd51 Collaboration Meeting, CERN Feb-2014

Gas mixture Ar:CH4 30:70. THGEM | V_MESH > Volts Effective gain X 10 ^3 DEL_V [V] 600 610 620 630 640 650 660 670 680 690 700 710 1720 12 14 17 21 25 31 38 46 56 69 84 102 1740 37 68 83 101 123 1760 20 30 45 55 67 82 100 121 148 1780 24 36 44 54 66 81 98 120 146 178 1800 29 53 65 79 97 118 144 176 214 1820 35 43 64 78 96 117 142 173 211 258 1840 52 63 77 94 115 140 171 209 255 310 1860 42 51 76 93 114 138 169 206 251 306 374 1880 62 75 92 112 137 167 203 248 302 369 449 1900 61 74 91 111 135 164 201 245 298 364 444 541 1920 73 90 109 133 162 198 241 294 359 438 534 651 1940 88 108 131 160 195 238 291 354 432 527 642 783 1960 106 130 158 193 235 287 350 426 520 634 773 943 1980 128 156 190 232 283 345 421 513 626 763 930 1135 V_MESH DEL_V G_THGEM G_MM G_MM/G_TH G_TOT G_Measured /1000 G_Calc/G_Meas *100 G_TH/G_MM G_Measured 600 1940 785.772 112.41779 0.143067 88334.75 86.5 102.1211 6.989748 86500 610 137.08963 0.174465 107721.2 115.8 93.02348 5.731812 115800 620 167.17608 0.212754 131362.3 164.3 79.9527 4.700266 164300 630 203.86547 0.259446 160191.8 187.1 85.61827 3.854365 187100 640 1920 652.9375 248.60692 0.380751 162324.8 168.9 96.10704 2.626385 168900 650 1900 542.5587 303.16758 0.558774 164486.2 166.4 98.84989 1.789633 166400 660 1860 374.6251 369.70242 0.98686 138499.8 134 103.3581 1.013315 134000 670 1840 311.2949 450.83937 1.448271 140344 133.5 105.1266 0.690479 133500 680 1820 258.6706 549.78308 2.125418 142212.7 137 103.8049 0.470496 137000 690 1800 214.9425 670.44154 3.119167 144106.4 130 110.851 0.320598 130000 700 1760 148.4132 817.58037 5.508813 121339.7 102.8 118.0347 0.181527 102800 710 1740 123.324 997.0111 8.084487 122955.4 114.31 107.5631 0.123694 114310 S Levorato. Rd51 Collaboration Meeting, CERN Feb-2014