T10: LGAD Sensors (402.8.4.1) Christopher Rogan University of Kansas US-MTD Technical Review 15-16 November 2018
Outline § CMS ETL sensor requirements and design § Introduction to LGAD sensors § LGAD Performance § Bench and testbeam measurements, radiation tolerance, uniformity and efficiency § R&D and prototyping plans and stages § Summary § Additional material: § QA and QC capabilities and plans for production-era LGADs Christopher Rogan – T10: LGAD Sensors US-MTD Technical Review 2
Charge #6 Biographical sketch § Christopher Rogan § Assistant Professor University of Kansas § Role in International MTD § Coordinator for ETL Validation and System Tests § Role in US-MTD § L3 Coordinator for MTD Common Systems § L4 Coordinator for ETL Sensors § Expertise § ECAL and HCAL reconstruction (jets/MET,Egamma) § Detector development and operations for ECAL and MTD § Extensive test beam experience for several systems § Data analysis and statistics expertise Christopher Rogan – T10: LGAD Sensors US-MTD Technical Review 3
Charge #1,5 Performance Requirements § CMS ETL Sensor Requirements: § High efficiency of measuring MIP timing 1 . 6 < | η | < 2 . 9 § 30-50 ps single track resolution resolution § Radiation hard to ensure performance to 4000 fb -1 “BTL” “ETL” § Extensive US expertise and contributions towards achieving these goals Christopher Rogan – T10: LGAD Sensors US-MTD Technical Review 4
Charge #1,4,5 LGAD Sensor Concept § “Low-Gain Avalanche Detector” (LGAD) Time Detector Position Detector § Combining precision position reconstruction with ultra-fast timing resolution LGAD § Large Community § RD50 Collaboration § Several manufacturers: CNM, FBK, Hamamatsu § Alternatives considered: § CMS (US-CMS) § Microchannel Plates (MCPs) § UCSB, FNAL, Genoa, Helsinki, § Cost efficiency and logistical risk IFCA, KIT, KU, Sevilla, Torino § Hyper-Fast Silicon (HFS) § +US ATLAS § Technical risk § Including Brookhaven, SLAC, UCSC Christopher Rogan – T10: LGAD Sensors US-MTD Technical Review 5
Charge #1,5 LGAD Sensor Concept § “Low-Gain Avalanche Detector” (LGAD) § Large signal, large slew-rate, low gain § Extra doping layer results in high field (~300 kV/cm) ⇒ avalanche signal with 10-30 gain § More signal in thinner sensor ⇒ short drift time, better timing resolution § Low gain (10’s vs. 1000’s for SiPM) ⇒ low shot noise, below electronics’ Christopher Rogan – T10: LGAD Sensors US-MTD Technical Review 6
Charge #1,5 ETL Layout 6in Si wafer § Basic unit is a module sensor layout sub-assembly § 16x32 LGAD pixels of size 1.3x1.3 mm 2 → 42x21 mm 2 § 2 ROC ASICS § Arranged in two layers per endcap § modules mounted on both sides of each layer to provide a “single layer” hermetic coverage § See Slawek Tkaczyk’s talk on ETL Modules ETL disk in this session layout Christopher Rogan – T10: LGAD Sensors US-MTD Technical Review 7
Charge #1,3,5 R&D Performance § Continued R&D program with significant US contributions to optimize sensor reference design, with answers to key questions using both bench and beam tests: § Radiation hardness: Comparison of LGAD gain-layer doping schemes to achieve design resolution at end of ETL life § Fill factor: Comparisons of geometries to achieve smallest size dead area between pads and physical sensor edges § Uniformity: Testing of both timing resolution and efficiency uniformity over increasingly large arrays of pads Christopher Rogan – T10: LGAD Sensors US-MTD Technical Review 8
Charge #1,3,5 FNAL Test Beam Facilities § Pixel Telescope with two DUT regions for testing 5 DUTs Nov. 2018 MTD TB Cold Box § 5 slots for LGAD boards § Cooling w/ chiller + Peltier § Remotely controlled motion stage § Nitrogen supply § Signals and power thru patch panel § Humidity meas. & control Christopher Rogan – T10: LGAD Sensors US-MTD Technical Review 9
Charge #1,3,5 Radiation Hardness § Challenge : Radiation tolerance and design performance throughout the eta range of the ETL ETL Christopher Rogan – T10: LGAD Sensors US-MTD Technical Review 10
Charge #1,3,5 Irradiated LGAD Performance § LGADs up to challenge § Required radiation tolerance and timing resolution demonstrated for 2x2 sensor arrays: 30 ps at 1 × 10 15 n eq / cm 2 § Uniformity of signals across irradiated HPK sensor area is maintained Christopher Rogan – T10: LGAD Sensors US-MTD Technical Review 11
Charge #1,3,5 Irradiated LGAD TB Performance CMS Preliminary Fermilab TB Dec. '17 - Apr. '18 LGAD Summary 80 FBK W8 non-irradiated 32 ps resolution up to FBK W6 ´ 2 14 8 10 n / cm eq FBK W1 70 ´ 15 2 µ 1.5 10 n / cm HPK 35 m eq 8 × 10 14 n eq / cm 2 60 (ps) 50 t s 43 ps resolution up to 40 1 . 5 × 10 15 n eq / cm 2 30 20 100 150 200 250 300 350 400 450 500 550 Bias Voltage (V) § Preliminary TB results consistent with lab measurements and reach required performance § Comparing bench tests at UCSC with FNAL TB results § Continuing to explore new doping strategies for improved rad tolerance § e.g. Boron-Carbon doped FBK shows smaller resolution degradations Christopher Rogan – T10: LGAD Sensors US-MTD Technical Review 12
Charge #1,3,5 Irradiated LGAD TB Performance CMS Preliminary Fermilab TB Nov. 2018 FBK LGAD *Preliminary* 2 W5 8e14 3x1 mm 55 2 W5 1.5e15 3x1 mm Time Resolution [ps] *Preliminary* FNAL TB results from data 50 taken Nov. 13, 2018 45 40 320 340 360 380 400 420 440 460 Bias Voltage [V] § Preliminary TB results consistent with lab measurements and reach required performance § Comparing bench tests at UCSC with FNAL TB results § Continuing to explore new doping strategies for improved rad tolerance § e.g. Boron-Carbon doped FBK shows smaller resolution degradations Christopher Rogan – T10: LGAD Sensors US-MTD Technical Review 13
Charge #1,3,5 Time Resolution § Testing variety of sensors from different manufacturers (now in 3 rd prototype round) and have measured: § time resolution of ~30 ps pre-irradiation § 100% MIP efficiency over sensitive area § Uniform sensor response HPK FBK Christopher Rogan – T10: LGAD Sensors US-MTD Technical Review 14
Charge #1,3,5 Fill Factor and Uniformity § Excellent uniformity observed on 2x2 mm 2 and 3x3 mm 2 pixel arrays from all manufacturers § In process of testing 1.3x1.3 mm 2 pixels for ETL § Verifying uniformity with smaller pixels in larger arrays ´ 3 10 27 1 m] µ Y position [ 0.9 26 0.8 0.7 25 0.6 0.5 24 0.4 23 0.3 0.2 22 0.1 ´ 3 10 21 0 17 18 19 20 21 22 23 µ X position [ m] FNAL Test Beam Data Christopher Rogan – T10: LGAD Sensors US-MTD Technical Review 15
Charge #3,10 Schedule and Plans § Schedule and plans organized around several R&D/prototyping, pre-production, and production periods: § Continuing program of R&D, test beams, irradiations associated with increasingly large sensors [2018-2020] § Studies of doping schema, sensor geometry, radiation resistance with increasing large channel arrays § Pre-production sensors with final geometry/doping/design choices [2020-2022] § Prototyping of complete modules, including integration with ASIC/flex electronics § Development and implementation of sensor QA/QC procedures, preparation of testing sites § Production sensors for CMS ETL [2022-2024] § Execution of the previously developed plans for sensor acquisition, testing, module assembly, and then installation Christopher Rogan – T10: LGAD Sensors US-MTD Technical Review 16
Summary § LGADs sensors are capable of meeting CMS ETL needs § 30-50 ps time resolution for MIPs § High efficiency of measuring MIP time over CMS ETL § Radiation hard to ensure performance to 4000 fb -1 § The use of LGADs is a prudent, robust choice that minimizes technical and logistical risk § Mature technology supported by large community § Cooperative design and testing between US CMS + ATLAS § Testbeam and radiation hardness testing of LGADs is proceeding in line with the R&D plans § Performance confirmed with smaller pixel arrays § Manufacturing and testing of larger arrays this year and next Christopher Rogan – T10: LGAD Sensors US-MTD Technical Review 17
Charge #4,9 Production Era: QA and QC Testing § Prototyping and R&D for LGAD QA § Ongoing activities in LGAD R&D prototype characterization from several vendors to ensure sensor quality and reliability § Primary QC facility in US at University of Kansas § Planned capability for batch testing 5% of total ETL sensor production (support in US-MTD up-scope option) § Developing/assembling QC procedures/facilities for visual inspections, bench characterization tests, and database cataloging of each sensor batch, with ongoing commissioning throughout prototyping phases § Institutional experience with silicon sensors (CMS pixels) and timing detectors (CT-PPS) with significant contributions to LGAD R&D and development Christopher Rogan – T10: LGAD Sensors US-MTD Technical Review 18
Backup Christopher Rogan – T10: LGAD Sensors US-MTD Technical Review 19
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