Calibration of Precise Large Area Micromegas Detectors Using Cosmic - - PowerPoint PPT Presentation
Calibration of Precise Large Area Micromegas Detectors Using Cosmic Rays Maximilian Herrmann Ludwig-Maximilians-Universit at M unchen - Lehrstuhl Schaile 02.03.2017, Novosibirsk Instrumentation for Colliding Beam Physics M. Herrmann (LMU
Maximilian Herrmann
Ludwig-Maximilians-Universit¨ at M¨ unchen - Lehrstuhl Schaile
02.03.2017, Novosibirsk Instrumentation for Colliding Beam Physics
Calibration of Micromegas 02.03.2017, Novosibirsk 1 / 16
1
Micromegas Principle Position and Track Reconstruction
2
Cosmic Ray Facility Calibration and Potential Alignment by use of µ reference tracks and by partitioning of the detector area
3
Calibration Results
4
Homogeneity and Efficiency of Large Area Micromegas
5
Summary
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cathode
+570 V mesh 0V resistive strip anode readout strips 0.128 mm 5 mm drift amplification
pitch 0.45 mm pillar
e- e- e- e- reconstructed charge average
tdrift cluster of strips Ar:CO2
ionized electrons drift between cathode and grounded mesh gas amplification between mesh and anode charge collection on resistive strips charge detection on readout strips positioning of strips with high accuracy mandatory
calibration ⇒ determine position of strips using cosmic muons
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two readout anode boards (due to photolithographic limitations) no alignment tooling used during gluing on Al plate active area: 0.92 × 1.02 m2
pillars strips drift cathode mesh stiffening panel stiffening panel Al frame PCB Al plate gas volume
stiffening panels as support structure for anode and cathode mesh mounted on drift panel gas volume enclosed by anode and cathode potential deformation due to
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beginning of the signal : fit by an inverse Fermi function
time [25 ns] 2 4 6 8 10 12 14 16 18 pulse height [ADC channel] 200 400 600 800 1000 1200 1400
extrapolation fit 90 % 50 % 10 % start time
fFermi = p0 1 + exp[(p1 − x)/p2] + p3 p0 : maximal pulse height ⇒ charge of signal p1 : time of 50% maximal pulse height p2 : ∝ rise time p3 : pedestal
⇒ 3 values of fFermi at 10% , 50% and 90% define start time of signal by extrapolation
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drift time measurement α
xcentroid
tdrift
centroid method ⇒ charge average over strips xcentroid =
xstrip · qstrip
qstrip TPC-like method angle reconstruction by drift time measurement α = arctan
slopefit · vdrift
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trigger scintillator trigger scintillator muon track MDT chamber MDT chamber test Micromegas detector reference track 1 reference track 2
2D track reconstruction with two Monitored Drift Tube (MDT) chambers trigger via Scintillator hodoscope with coarse resolution (≈ 10 cm) in
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facility to calibrate detectors in Garching near Munich MDT chambers : 2.2 m × 4 m ⇒ active area : 9 m2 angular acceptance : ±30◦
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Idea:
reference track detector detector under study perpendicular track assumed position measured position shift residual reference track detector detector under study inclined track assumed position measured position shift perpendicular track residual slope reference track 0.6 − 0.4 − 0.2 − 0.2 0.4 0.6 residual in y [mm] 5 − 4 − 3 − 2 − 1 − 1 2 3 4 5
/ ndf
2
χ 109.4 / 96 intercept 0.002805 ± 0.3986 slope 0.01115 ± 0.3544 −
50 100 150 200 250
/ ndf
2
χ 109.4 / 96 intercept 0.002805 ± 0.3986 slope 0.01115 ± 0.3544 −
Implementation: residual = posmeasured − posreference residual vs. slope
⇒ linear fit shifthorizontal = interceptfit shiftvertical = slopefit
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92 cm 102 cm 10 segments 16 segments
1 14 15 …………... 7 8 …………...
128 channels
APV
PCB 1 PCB 2 z x y
two readout boards with in 2048 strips 16 APV25 frontend boards ⇒ 16 segments in y direction 10 cm resolution of scintillator hodoscope ⇒ 10 segments in x direction
⇒ 160 partitions
` a 100 × 57.6 mm2
⇒ calibration and alignment for each of the 160 partitions individually
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x [ 1 m m ] 0 1 2 3 4 5 6 7 8 9 10 y [57.6 mm] 2 4 6 8 10 12 14 16 z [mm] 0.4 − 0.3 − 0.2 − 0.1 − 0.1 0.2 0.3 0.4 − 0.3 − 0.2 − 0.1 − 0.1 0.2 0.3 0.50 0.84 1.17 1.51 0.17 Deformation [mm]
mesh stiff base plate gas in tracks reconstructed z position cathode gas out 10 mbar
drift gap deformation due to small overpressure maximum deviation of 0.8 mm from central plane ⇒ 1.6 mm at cathode (stiff base plate support) deformation in agreement with finite element simulation (ANSYS)
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x [100 mm] 1 2 3 4 5 6 7 8 9 10 y [ 5 7 . 6 m m ] 2 4 6 8 10 12 14 16 mean residual y [mm] 0.6 − 0.5 − 0.4 − 0.3 − 0.2 − 0.1 − 0.1 mean residual y [mm] 0.6 − 0.5 − 0.4 − 0.3 − 0.2 − 0.1 −
analysis of all 160 partitions individually alignment of the right half of the detector ⇒ misalignment between PCBs becomes visible shift : 0.1 mm rotation : 0.35 mm/m 50 µm effects are clearly
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Entries 160685 Mean 0.001863 − RMS 0.3508 Integral 1.563e+05 / ndf
2χ 439.7 / 34
coreA 9.372e+01 ± 2.375e+04
coreµ 0.0007018 ± 0.0009471 −
coreσ 0.0008 ± 0.2102
tailsA 42.8 ± 1854
tailsµ 0.00414 ± 0.00326 −
tailsσ 0.0059 ± 0.6635
residual in y at 0° [mm] 2 − 1.5 − 1 − 0.5 − 0.5 1 1.5 2 counts 5 10 15 20 25
3
10 ×
Entries 160685 Mean 0.001863 − RMS 0.3508 Integral 1.563e+05 / ndf
2χ 439.7 / 34
coreA 9.372e+01 ± 2.375e+04
coreµ 0.0007018 ± 0.0009471 −
coreσ 0.0008 ± 0.2102
tailsA 42.8 ± 1854
tailsµ 0.00414 ± 0.00326 −
tailsσ 0.0059 ± 0.6635
] ° angle reference track [ 20 − 10 − 10 20 residual width [mm] 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
fully calibrated shift corrected not calibrated
centroid position reconstruction fit residual distribution for each angle with double Gaussian plot narrow Gaussian width as function of angle ⇒ calibration improves resolution improvement @ 0◦ : ≈ 100 µm
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weighted width
] ° angle reference track [ 20 − 10 − 10 20 residual width [mm] 0.2 0.4 0.6 0.8 1 1.2 no cut slope difference < 0.01 slope difference < 0.005 slope difference < 0.001 slope difference < 0.0005
Entries 127276 Mean 0.06446 RMS 0.622 Integral 1.233e+05 / ndf
2χ 550.6 / 44
coreA 59.4 ± 9462
coreµ 0.00158 ± 0.06263
coreσ 0.0023 ± 0.3004
tailsA 43.3 ± 2282
tailsµ 0.00440 ± 0.06882
tailsσ 0.0066 ± 0.9064
[mm] ° residual in y at 0 2.5 − 2 − 1.5 − 1 − 0.5 − 0.5 1 1.5 2 2.5 counts 2 4 6 8 10 12
3
10 ×
Entries 127276 Mean 0.06446 RMS 0.622 Integral 1.233e+05 / ndf
2χ 550.6 / 44
coreA 59.4 ± 9462
coreµ 0.00158 ± 0.06263
coreσ 0.0023 ± 0.3004
tailsA 43.3 ± 2282
tailsµ 0.00440 ± 0.06882
tailsσ 0.0066 ± 0.9064
couts 500 1000 1500 2000 2500 3000 3500 4000 no cuts cut on slope differnce
assumption: multiple scattering of muons ⇒ broadening of residual distributions centroid residual distribution fit with double Gaussian ⇒ weighted sigma cut on slope difference of reference tracks decreases residual width by 350 µm
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MPV of charge distribution [ADC counts]
748.677 811.028 883.7 946.354 1007.84 1088.5 1133.79 1162.39 1225.61 1213.27 935.488 1011.44 1077.33 1173.6 1253.63 1356.12 1397.84 1468.29 1490.96 1387.83 968.686 1051.01 1092.8 1160.89 1272.84 1381.34 1417.81 1455.99 1438.56 1312.37 1207.45 1296.9 1342.4 1424.24 1543.17 1641.19 1647.16 1715.11 1650.16 1478.31 1110.81 1180.58 1199.67 1261.87 1352.17 1415.48 1469.88 1469.48 1351.66 1188.87 1443.02 1562.7 1615.42 1658.92 1797.61 1870.02 1857.42 1804.07 1673.24 1434.55 1083.93 1187.22 1206.49 1234.21 1305.97 1343.1 1289.18 1251.25 1140.39 961.671 1399.94 1491.5 1586.87 1575.25 1639.28 1675.67 1605.58 1580 1414.47 1232.26 1232.1 1322.16 1100.79 1310.47 1545.79 1494.66 1321.58 1233.76 1205.67 1100.92 1738.4 1933.48 1887.29 2232.02 2159.5 2034.1 1894.14 1728.85 1598.73 1473.3 1326.56 1423.22 1465.96 1622.11 1614.78 1472.56 1343.02 1256.92 1151.06 1069.48 1885.87 1964.78 1978.79 2230 2158.21 1974.85 1766.06 1625.95 1471.27 1321.97 1224.52 1267.18 1288.27 1400.37 1345.61 1244.14 1129.21 1044.27 967.964 882.009 1860.82 1915.88 1945.11 2141.73 2084.21 1868.21 1624.26 1492.73 1321.73 1180.97 1636.08 1639.46 1663.35 1732.09 1687.66 1561.2 1347.72 1266 1124.3 988.789 1824.62 1793.81 1776.19 1864.36 1756.61 1620.28 1462.62 1339.51 1155.97 1022.6
x [100mm] 1 2 3 4 5 6 7 8 9 10 y [57.6mm] 2 4 6 8 10 12 14 16 800 1000 1200 1400 1600 1800 2000 2200
efficiency [%]
90.98 91.21 90.73 90.69 90.84 90.7 91.09 90.39 91.25 91.08 92.07 92.02 92.18 91.96 92.16 91.89 92.29 91.96 92.29 92.05 91.04 91.15 91.06 91.57 91.28 91.44 91.22 91.46 91.34 90.88 90.07 90.52 90.94 91.08 90.97 90.93 90.93 90.69 90.36 89.56 90.57 90.83 91.31 91.03 91.17 90.99 91.18 91.15 90.8 89.66 91.42 91.69 91.96 92.23 92.07 92.01 92.07 91.73 91.35 90.28 89.91 90.33 90.36 90.6 90.42 90.42 90.41 90.1 90.05 88.76 92.03 92.62 93.02 92.87 92.85 92.74 92.81 92.49 91.93 91.27 89.83 90.33 90.59 91.09 91.02 90.63 90.75 90.3 90.19 89.6 92.09 92.31 93.02 93.44 93.3 93.17 93.1 93.04 92.72 92.31 90.29 90.78 91.19 91.09 91.37 91.13 90.93 90.9 90.75 90.02 92.1 92.51 93.02 93.43 93.07 92.86 93.04 92.61 92.54 91.7 90.1 91 91.19 91.61 91.46 91.21 90.96 90.47 90.31 89.59 92.53 92.59 92.84 93.14 93.03 92.95 92.85 92.77 92.73 92.61 90.73 91.25 91.46 91.65 91.52 91.33 91.16 90.98 91.28 91.19 91.81 91.55 91.64 91.72 91.62 91.54 91.45 91.24 91.34 91.11
x [100 mm] 1 2 3 4 5 6 7 8 9 10 y [57.6 mm] 2 4 6 8 10 12 14 16 89 89.5 90 90.5 91 91.5 92 92.5 93
charge average : 1440 ± 310 ADC channel efficiency average : 91.5 ± 0.9 % no significant difference between readout boards master-slave differences of APV25 frontend boards homogeneous 3σ efficiency (deviations due to border effects) 91.5 % limited by multiple scattering
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Cosmic Ray Facility position and track reconstruction investigation of 1 m2 Micromegas detector
deformation due to overpressure (1.6 mm @ 10 mbar) misalignment of the readout PCBs during assembly (100 - 450 µm) (no alignment tool available) broadening of the residual distribution due to multiple scattering of muons homogeneous pulse height and high efficiency over large area
results of calibration:
deviation of micro-strips detectable with sensitivity < 50 µm deformations of the active volume perpendicular to the readout area are measurable with sensitivity < 100 µm
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charge integration over 25 ns pairwise connection as master-slave to reduce output channels
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] ° reference track angle [ 10 15 20 25 30 ] ° reconstructed angle [ 10 15 20 25 30 35
without charge correction with charge correction
resistive strips readout strips
angular reconstruction via TPC like method [ tDrift = f(strip) ] reference track angle by MDT chambers larger angles reconstructed due to capacitive coupling between 1 m long strips ⇒ correction improves angular resolution
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