T10: LGAD Sensors (402.8.4.1) Christopher Rogan University of - - PowerPoint PPT Presentation

T10: LGAD Sensors (402.8.4.1)

Christopher Rogan University of Kansas US-MTD Technical Review 15-16 November 2018

Christopher Rogan – T10: LGAD Sensors US-MTD Technical Review 2

§ 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

Outline

Christopher Rogan – T10: LGAD Sensors US-MTD Technical Review 3

§ 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

Biographical sketch

Charge #6

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Performance Requirements

Charge #1,5

§ CMS ETL Sensor Requirements:

§ High efficiency of measuring MIP timing § 30-50 ps single track resolution resolution § Radiation hard to ensure performance to 4000 fb-1

§ Extensive US expertise and contributions towards achieving these goals

1.6 < |η| < 2.9

“BTL” “ETL”

Christopher Rogan – T10: LGAD Sensors US-MTD Technical Review 5

LGAD Sensor Concept

Charge #1,4,5

§ “Low-Gain Avalanche Detector” (LGAD)

§ Combining precision position

reconstruction with ultra-fast timing resolution

§ Alternatives considered:

§ Microchannel Plates (MCPs)

§ Cost efficiency and logistical risk

§ Hyper-Fast Silicon (HFS)

§ Technical risk

§ Large Community

§ RD50 Collaboration § Several manufacturers:

CNM, FBK, Hamamatsu

§ CMS (US-CMS)

§ UCSB, FNAL, Genoa, Helsinki,

IFCA, KIT, KU, Sevilla, Torino

§ +US ATLAS

§ Including Brookhaven, SLAC, UCSC

Time Detector Position Detector LGAD

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LGAD Sensor Concept

Charge #1,5

§ “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’

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ETL Layout

Charge #1,5

§ Basic unit is a module sub-assembly

§ 16x32 LGAD pixels

• f size 1.3x1.3 mm2

→ 42x21 mm2

§ 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 in this session

6in Si wafer sensor layout ETL disk layout

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R&D Performance

Charge #1,3,5

§ 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

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FNAL Test Beam Facilities

Charge #1,3,5

§ Pixel Telescope with two DUT regions for testing

5 DUTs

§ 5 slots for LGAD boards § Remotely controlled motion stage § Signals and power thru patch panel § Cooling w/ chiller + Peltier § Nitrogen supply § Humidity meas. & control

Cold Box

• Nov. 2018 MTD TB

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Radiation Hardness

Charge #1,3,5

§ Challenge: Radiation tolerance and design performance throughout the eta range of the ETL

ETL

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Irradiated LGAD Performance

Charge #1,3,5

§ LGADs up to challenge

§ Required radiation

tolerance and timing resolution demonstrated for 2x2 sensor arrays:

§ Uniformity of signals across irradiated HPK sensor area is maintained

30 ps at 1 × 1015neq/cm2

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Irradiated LGAD TB Performance

Charge #1,3,5

§ 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

1.5 × 1015neq/cm2

43 ps resolution up to

100 150 200 250 300 350 400 450 500 550

Bias Voltage (V)

20 30 40 50 60 70 80

(ps)

t

s

FBK W8 FBK W6 FBK W1 m µ HPK 35 non-irradiated

2

/ cm

eq

n

14

10 ´ 8

2

/ cm

eq

n

15

10 ´ 1.5

CMS Preliminary

Fermilab TB Dec. '17 - Apr. '18 LGAD Summary

32 ps resolution up to

8 × 1014neq/cm2

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Irradiated LGAD TB Performance

Charge #1,3,5

§ 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

*Preliminary* FNAL TB results from data taken Nov. 13, 2018

320 340 360 380 400 420 440 460 Bias Voltage [V] 40 45 50 55 Time Resolution [ps]

2

W5 8e14 3x1 mm

2

W5 1.5e15 3x1 mm Fermilab TB Nov. 2018 FBK LGAD *Preliminary*

CMS Preliminary

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Time Resolution

Charge #1,3,5

FBK HPK

§ Testing variety of sensors from different manufacturers (now in 3rd prototype round) and have measured:

§ time resolution of ~30 ps pre-irradiation § 100% MIP efficiency over sensitive area § Uniform sensor response

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Fill Factor and Uniformity

Charge #1,3,5

§ Excellent uniformity observed on 2x2 mm2 and 3x3 mm2 pixel arrays from all manufacturers

§ In process of testing 1.3x1.3 mm2 pixels for ETL § Verifying uniformity with smaller pixels in larger arrays

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 17 18 19 20 21 22 23

3

10 ´ m] µ X position [ 21 22 23 24 25 26 27

3

10 ´ m] µ Y position [

FNAL Test Beam Data

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Schedule and Plans

Charge #3,10

§ 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

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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

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§ 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

Production Era: QA and QC Testing

Charge #4,9

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Backup