Construction and Quality Assurance of Large Area Resistive Strip Micromegas for the Upgrade of the ATLAS Muon Spectrometer Philipp L¨ osel on behalf of the ATLAS Muon Collaboration LS Schaile Ludwig-Maximilians-Universit¨ at M¨ unchen Instrumentation for Colliding Beam Physics Novosibirsk 2017 02.03.2017 Philipp L¨ osel (LMU) Construction and QA of NSW Micromegas 02.03.2017 1 / 26
Outline Motivation for the ATLAS NSW Upgrade Project 1 Construction of NSW Micromegas Quadruplets 2 Design of the Micromegas Quadruplets Requirements for Micromegas Detectors Panel Construction Alignment of the Readout Boards Quality Assurance of NSW Micromegas Quadruplets 3 Planarity Measurement of the Panels Verification of Strip Alignment High Rate Irradiation Tests Summary 4 Philipp L¨ osel (LMU) Construction and QA of NSW Micromegas 02.03.2017 2 / 26
High Luminosity Upgrade of LHC LHC high luminosity upgrade 2021: Run 3: 2 × L design 2026: Run 4: 5 − 7 × L design upgrade of inner end-cap region of Muon Spectrometer (Small Wheels) before Run 3 Philipp L¨ osel (LMU) Construction and QA of NSW Micromegas 02.03.2017 3 / 26
Motivation for the ATLAS NSW Upgrade Project full inclusion of New Small Wheel in trigger 90 % of trigger are fake in end-cap region A track pointing to IP (good muon track) B no hit in Small Wheel (fake) C background event: not pointing to IP (fake) MDT efficiency loss: L > L design = ⇒ ε < 90 % L > 2 L design = ⇒ ε < 60 % maintain current excellent momentum resolution for higher luminosity: 1 mrad resolution + trigger capability needed ∆ p T ≈ 15 % @ p T = 1 TeV muons = ⇒ New Small Wheel needs trigger and high rate capable new technology: sTGC and Micromegas Philipp L¨ osel (LMU) Construction and QA of NSW Micromegas 02.03.2017 4 / 26
Outline Motivation for the ATLAS NSW Upgrade Project 1 Construction of NSW Micromegas Quadruplets 2 Design of the Micromegas Quadruplets Requirements for Micromegas Detectors Panel Construction Alignment of the Readout Boards Quality Assurance of NSW Micromegas Quadruplets 3 Planarity Measurement of the Panels Verification of Strip Alignment High Rate Irradiation Tests Summary 4 Philipp L¨ osel (LMU) Construction and QA of NSW Micromegas 02.03.2017 5 / 26
Layout of the New Small Wheel disk-like design: eight large sectors eight small sectors sector: two Micromegas wedges sandwiched by two sTGC wedges = ⇒ eight layers of sTGCs (trigger) eight layers of Micromegas (tracker) Micromegas wedges subdivided in two Micromegas quadruplets sector wedges sTGC MM Chambers sTGC Micromegas quadruplet strip layout 2 x 4 active layers Philipp L¨ osel (LMU) Construction and QA of NSW Micromegas 02.03.2017 6 / 26
Design of the Micromegas Quadruplets 2-3 m 2 Micromegas Micromegas quadruplets: three drift panels two readout panels four meshes mounted on drift panels four gas volumes between panels are the active Micromegas layers Philipp L¨ osel (LMU) Construction and QA of NSW Micromegas 02.03.2017 7 / 26
Resistive Strip Micromegas single active plane of a resistive strip Micromegas detector quadruplet: µ cathode 300 V cathode ionization grounded micro-mesh drift drift 5 mm t drift anode strip structure pillar position reconstruction: mesh 0 V 0.128 mm amplification anode charge centroid over strip-cluster resistive strips 570 V readout strips track reconstruction via µ cluster t drift = f ( strip ) Al frame drift cathode stiffening panel stiffening panel stiffening panel stiffening panel PCB pillars strips mesh Philipp L¨ osel (LMU) Construction and QA of NSW Micromegas 02.03.2017 8 / 26
Production of Resistive Strip Readout Boards resistive pattern Kapton foil PCB with readout strips copper readout strips PCB Kapton foil with resistive pattern aligned to readout strips with markers Polymer Kapton foil glued on top of silver conduct readout strips HV connection silver connection between HV connector and resistive pattern 128 µ m coverlay pillars as coverlay pillar mesh support Philipp L¨ osel (LMU) Construction and QA of NSW Micromegas 02.03.2017 9 / 26
Requirements for Micromegas maintain current excellent momentum resolution for higher luminosity: ∆ p T ≈ 15 % @ p T = 1 TeV muons = ⇒ 100 µ m spatial resolution in a single plane 30 µ m alignment accuracy of readout strips on the individual PCBs and particularly the alignment within a quadruplet 80 µ m accuracy perpendicular to the plane Philipp L¨ osel (LMU) Construction and QA of NSW Micromegas 02.03.2017 10 / 26
Panel Construction in two Gluing Steps: Step 1 PCBs granite table vacuum PCBs placed and aligned on granite table Philipp L¨ osel (LMU) Construction and QA of NSW Micromegas 02.03.2017 11 / 26
Panel Construction in two Gluing Steps: Step 1 sealing tape glue granite table vacuum PCBs placed and aligned on granite table sucked to granite table and sealed with tape = ⇒ planarity transfer glue distributed on PCBs Philipp L¨ osel (LMU) Construction and QA of NSW Micromegas 02.03.2017 11 / 26
Panel Construction in two Gluing Steps: Step 1 aluminum bars honeycomb halfpanel granite table vacuum PCBs placed and aligned on granite table sucked to granite table and sealed with tape = ⇒ planarity transfer glue distributed on PCBs aluminum bars and honeycomb placed on top halfpanel cures over night in vacuum bag Philipp L¨ osel (LMU) Construction and QA of NSW Micromegas 02.03.2017 11 / 26
Panel Construction in two Gluing Steps: Step 2 stiffback perforated honeycomb vacuum honeycomb alu alu halfpanel precision distance pieces granite table vacuum PCBs placed and aligned on granite table sucked to granite table and sealed with tape = ⇒ planarity transfer glue distributed on PCBs aluminum bars and honeycomb placed on top halfpanel cures over night in vacuum bag halfpanel removed and sucked to stiffback second set of PCBs placed on granite table glue distributed on PCBs Philipp L¨ osel (LMU) Construction and QA of NSW Micromegas 02.03.2017 11 / 26
Panel Construction in two Gluing Steps: Step 2 stiffback perforated honeycomb vacuum granite table vacuum PCBs placed and aligned on granite table sucked to granite table and sealed with tape = ⇒ planarity transfer glue distributed on PCBs aluminum bars and honeycomb placed on top halfpanel cures over night in vacuum bag halfpanel removed and sucked to stiffback second set of PCBs placed on granite table glue distributed on PCBs stiffback with halfpanel placed on distance pieces = ⇒ well defined panel thickness Philipp L¨ osel (LMU) Construction and QA of NSW Micromegas 02.03.2017 11 / 26
Panel Construction in one Gluing Step main difference: no halfpanel, only PCBs sucked to stiffback stiffback perforated honeycomb vacuum precision distance pieces alu honeycomb alu all granite table other steps vacuum as stiffback before perforated honeycomb vacuum granite table vacuum Philipp L¨ osel (LMU) Construction and QA of NSW Micromegas 02.03.2017 12 / 26
Panel Construction in one Gluing Step Philipp L¨ osel (LMU) Construction and QA of NSW Micromegas 02.03.2017 13 / 26
Alignment of the Readout Boards Philipp L¨ osel (LMU) Construction and QA of NSW Micromegas 02.03.2017 14 / 26
Two Versions of Alignment: Precision Holes or Washers precision washer accurate alignment frame planar precision plates global alignment on granite table well aligned relative alignment using pins pins + precision holes glued @ position of target washer gluing accuracy < 5 μm Philipp L¨ osel (LMU) Construction and QA of NSW Micromegas 02.03.2017 15 / 26
Two Versions of Alignment: Precision Holes or Washers precision washer accurate alignment frame planar precision plates global alignment on granite table well aligned relative alignment using pins pins + precision holes glued @ position of target Philipp L¨ osel (LMU) Construction and QA of NSW Micromegas 02.03.2017 15 / 26
Two Versions of Alignment: Precision Holes or Washers precision washer accurate alignment frame planar precision plates global alignment on granite table well aligned relative alignment using pins pins + precision holes glued @ position of target Philipp L¨ osel (LMU) Construction and QA of NSW Micromegas 02.03.2017 15 / 26
Mesh Stretching and Mounting mesh stretching: in cleanroom pneumatic clamps 1. step: glued on transfer frame 2. step: glued onto mesh frame tension ≈ 11 N/cm Philipp L¨ osel (LMU) Construction and QA of NSW Micromegas 02.03.2017 16 / 26
Mesh Stretching and Mounting 14 y [mm] 1400 11.6 11.8 11.6 11.8 11.8 11.6 11.6 11 13 1200 11.6 12.6 12.2 12 12 12.4 12.4 12.2 1000 12 11.8 11.8 11.8 11.8 12 12 12 12 800 11 11 11.2 10.8 11.2 11.2 11.2 11.6 11.6 600 10 400 11.6 11.6 11.4 11.6 11.6 11.6 11.8 11.8 9 200 11.8 11.6 11.6 11.6 11.4 11.2 11.2 11 0 8 0 200 400 600 800 1000 1200 1400 1600 1800 2000 Average mesh tension: 11.66 +- 0.38 N/cm (RMS) x [mm] mesh stretching: in cleanroom pneumatic clamps 1. step: glued on transfer frame 2. step: glued onto mesh frame tension ≈ 11 N/cm Philipp L¨ osel (LMU) Construction and QA of NSW Micromegas 02.03.2017 16 / 26
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