A HV-MAPS Pixel Tracker for the Mu3e Experiment

(1)

A HV-MAPS Pixel Tracker for the Mu3e Experiment

Heiko Augustin

Physikalisches Institut Heidelberg

DPG Spring Meeting T72.1 02. March 2016

HighRR

(2)

Mu3e

The Physics Goal

µ ⁺ → e ⁺ e ⁻ e ⁺ suppressed to a BR below 10 ⁻⁵⁴ in the Standard Model

Any observed signal is a sign for new physics

Current limit BR < 10 ⁻¹² (SINDRUM) Aiming for sensitivity of 1 in 10 ¹⁶ decays

SINDRUM: "Search for the decay muto3e" Nucl. Phys.,B299 1, 1988

(3)

Mu3e

The Physics Goal

µ ⁺ → e ⁺ e ⁻ e ⁺ suppressed to a BR below 10 ⁻⁵⁴ in the Standard Model

Any observed signal is a sign for new physics

Current limit BR < 10 ⁻¹² (SINDRUM) Aiming for sensitivity of 1 in 10 ¹⁶ decays

SINDRUM: "Search for the decay muto3e" Nucl. Phys.,B299 1, 1988

(4)

Mu3e

The Physics Goal

µ ⁺ → e ⁺ e ⁻ e ⁺ suppressed to a BR below 10 ⁻⁵⁴ in the Standard Model

Any observed signal is a sign for new physics

Current limit BR < 10 ⁻¹² (SINDRUM) Aiming for sensitivity of 1 in 10 ¹⁶ decays

SINDRUM: "Search for the decay muto3e" Nucl. Phys.,B299 1, 1988

(5)

The Signal Decay

Muons decay at rest: Σ~ p = 0

Common vertex and coincident in time Maximal momentum 53 MeV/c

Reconstruct invariant mass from

charged particle tracks ( E _tot = m _µ )

(6)

The Background

Accidental & Combinatorial

e ⁺

e ⁺ e ^-

10 ⁹ decays per second Gives rise to accidental &

combinatorial background

Good time and vertex resolution

needed

(7)

The Background

Accidental & Combinatorial

e ⁺

e ⁺ e ^-

10 ⁹ decays per second Gives rise to accidental &

combinatorial background

Good time and vertex resolution

needed

(8)

The Background

Irreducible

Br anching R a tio

m _μ - E _tot (MeV)

0 1 2 3 4 5 6

10 ^-12

10 ^-16

10 ^-18 10 ^-13

10 ^-17 10 ^-15 10 ^-14

10 ^-19 μ3e

R.M.Djilkibaev and R.V.Konoplich, Phys.Rev.,

D79 073004, 2009

Irreducible background from radiative decays with internal conversion:

µ ⁺ → e ⁺ e ⁻ e ⁺ ¯ ν _µ ν _e

Good momentum resolution needed to suppress SM background

Momentum resolution is dominated by multiple scattering ∝ √

x /p

(9)

The Detector

1T magnetic field

Target

μ Beam

(10)

The Detector

1T magnetic field

Target

μ Beam

(11)

The Detector

1T magnetic field

Target

Inner pixel layers

μ Beam

(12)

The Detector

1T magnetic field

Target Inner pixel layers

Outer pixel layers

μ Beam

(13)

The Detector

1T magnetic field

Target Inner pixel layers

Scintillating fibres

Outer pixel layers

μ Beam

(14)

The Detector

1T magnetic field

Target Inner pixel layers

Scintillating fibres

Outer pixel layers Recurl pixel layers

Scintillator tiles

μ Beam

(15)

The Requirements for the Silicon Pixel Tracker

Target Inner pixel layers

Scintillating fibres

Outer pixel layers Recurl pixel layers

Scintillator tiles

μ Beam

Good vertex resolution

Good time resolution & low dead time

→ fast signal generation & shaping

Good momentum resolution → low material budget

(16)

The Requirements for the Silicon Pixel Tracker

Pixel Sensor Requirements

Pixel Size Time Resolution Material Budget Efficiency 80 × 80 µm ² < 20 ns < 1 h X 0 /layer > 99 %

Good vertex resolution

Good time resolution & low dead time

→ fast signal generation & shaping

Good momentum resolution → low material budget

(17)

The Pixel Tracker

Readout & Powering via

Flexprints: T42.7

Cooling in Helium

atmosphere: T75.2

(18)

The Pixel Tracker

12345678910111213

141516171819

20212223

2425

262728293031

323334353637

3839 40414243

44

454647484950

51525354555657

585960

61626364

65666768697071

72737475767778 12345678910 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 3637383940 12345678910 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 3637383940 12345678910 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 3637383940

Mu3e Vertex Flex v1

A1 U1 U2 U3

A1

A1x1A1x2A1x3A1x4A1x5A1x6A1x7A1x8A1x9A1x10A1x11A1x12A1x13

A1x14A1x15A1x16A1x17A1x18A1x19

A1x20A1x21A1x22A1x23

A1x24A1x25

A1x38A1x39 A1x40A1x41A1x42A1x43

A1x44

A1x51A1x52A1x53A1x54A1x55A1x56A1x57

A1x58A1x59A1x60

U1

U1x1U1x2U1x3U1x4U1x5U1x6U1x7U1x8U1x9U1x10U1x11U1x12U1x13U1x14U1x15U1x16U1x17U1x18U1x19U1x20U1x21U1x22U1x23U1x24U1x25U1x26U1x27U1x28U1x29U1x30U1x31U1x32U1x33U1x34U1x35U1x36U1x37U1x38U1x39U1x40

U2

U3

A1

A1x24A1x25

A1x38A1x39 A1x40A1x41A1x42A1x43

A1x44

A1x58A1x59A1x60

U1

U2

U3

A1

A1x24A1x25

A1x38A1x39 A1x40A1x41A1x42A1x43

A1x44

A1x58A1x59A1x60

U1

U2

U3

A1

A1x24A1x25

A1x38A1x39 A1x40A1x41A1x42A1x43

A1x44

A1x58A1x59A1x60

U1

U2

U3

A1

A1x24A1x25

A1x38A1x39 A1x40A1x41A1x42A1x43

A1x44

A1x58A1x59A1x60

U1

U2

U3

A1

A1x24A1x25

A1x38A1x39 A1x40A1x41A1x42A1x43

A1x44

A1x58A1x59A1x60

U1

U2

U3

A1

A1x24A1x25

A1x38A1x39 A1x40A1x41A1x42A1x43

A1x44

A1x58A1x59A1x60

U1

U2

U3

A1

A1x24A1x25

A1x38A1x39 A1x40A1x41A1x42A1x43

A1x44

A1x58A1x59A1x60

U1

U2

U3

A1

A1x24A1x25

A1x38A1x39 A1x40A1x41A1x42A1x43

A1x44

A1x58A1x59A1x60

U1

U2

U3

A1

A1x24A1x25

A1x38A1x39 A1x40A1x41A1x42A1x43

A1x44

A1x58A1x59A1x60

U1

U2

U3

A1

A1x24A1x25

A1x38A1x39 A1x40A1x41A1x42A1x43

A1x44

A1x58A1x59A1x60

U1

U2

U3

A1

A1x24A1x25

A1x38A1x39 A1x40A1x41A1x42A1x43

A1x44

A1x58A1x59A1x60

U1

U2

U3

A1

A1x24A1x25

A1x38A1x39 A1x40A1x41A1x42A1x43

A1x44

A1x58A1x59A1x60

U1

U2

U3

A1

A1x24A1x25

A1x38A1x39 A1x40A1x41A1x42A1x43

A1x44

A1x58A1x59A1x60

U1

U2

U3

A1

A1x24A1x25

A1x38A1x39 A1x40A1x41A1x42A1x43

A1x44

A1x58A1x59A1x60

U1

U2

U3

A1

A1x24A1x25

A1x38A1x39 A1x40A1x41A1x42A1x43

A1x44

A1x58A1x59A1x60

U1

U2

U3

A1

A1x24A1x25

A1x38A1x39 A1x40A1x41A1x42A1x43

A1x44

A1x58A1x59A1x60

U1

U2

U3

A1

A1x24A1x25

A1x38A1x39 A1x40A1x41A1x42A1x43

A1x44

A1x58A1x59A1x60

U1

U2

U3

A1

A1x24A1x25

A1x38A1x39 A1x40A1x41A1x42A1x43

A1x44

A1x58A1x59A1x60

U1

U2

U3

A1

A1x24A1x25

A1x38A1x39 A1x40A1x41A1x42A1x43

A1x44

A1x58A1x59A1x60

U1

U2

U3

A1

A1x24A1x25

A1x38A1x39 A1x40A1x41A1x42A1x43

A1x44

A1x58A1x59A1x60

U1

U2

U3

A1

A1x24A1x25

A1x38A1x39 A1x40A1x41A1x42A1x43

A1x44

A1x58A1x59A1x60

U1

U2

U3

A1

A1x24A1x25

A1x38A1x39 A1x40A1x41A1x42A1x43

A1x44

A1x58A1x59A1x60

U1

U2

U3

A1

A1x24A1x25

A1x38A1x39 A1x40A1x41A1x42A1x43

A1x44

A1x58A1x59A1x60

U1

U2

U3

A1

A1x24A1x25

A1x38A1x39 A1x40A1x41A1x42A1x43

A1x44

A1x58A1x59A1x60

U1

U2

U3

A1

A1x24A1x25

A1x38A1x39 A1x40A1x41A1x42A1x43

A1x44

A1x58A1x59A1x60

U1

U2

U3

A1

A1x24A1x25

A1x38A1x39 A1x40A1x41A1x42A1x43

A1x44

A1x58A1x59A1x60

U1

U2

U3

A1

A1x24A1x25

A1x38A1x39 A1x40A1x41A1x42A1x43

A1x44

A1x58A1x59A1x60

U1

U2

U3

Readout & Powering via

Flexprints: T42.7

Cooling in Helium

atmosphere: T75.2

(19)

The Pixel Tracker

Readout

1056 Pixel Sensors

up to 36 1.25 Gbit/s links

FPGA FPGA FPGA

...

34 FPGAs

Switching Boards 1 6 Gbit/s link each

GPU

PC GPU

PC 12 PCs ...

12 10 Gbit/s links per Switching Board

2 Inputs each

Data Collection

Server

Mass Storage Gbit Ethernet

Front-end (inside magnet)

Untriggered readout 1 Tbit/s raw data rate GPU based online reconstruction Sessions:

T42.5, T42.6, T22.5, T22.4,

T98.1, T98.5

(20)

High Voltage Monolithic Active Pixel Sensors

P-substrate N-well

Particle E field

I.Peric, P. Fischer et al., NIM A 582 (2007) 87

Deep n-well in p-doped substrate

Depleted area is the active detector volume ≈ 15 µm Fast charge collection via drift

Sensor can be thinned to < 50 µm

(21)

The MuPix7 Prototype

Commercial 180 nm HV-CMOS process

Thinned to 50 µm

(22)

The MuPix7 Prototype

(23)

The MuPix7 Prototype

Pixel Periphery State Machine

readout state machine

VCO

&

PLL

8b/10b

encoder serializer LVDS .. .

oth er pixels

sensor CSA

comparator tune

DAC

threshold baseline source

follower

test-pulse injection

readout 2 ^nd amplifier

integrate charge

amplification

line driver

digital output AC coupling

via CR filter

per pixel

threshold

adjustment

(24)

The Pixel

3 . 2 × 3 . 2 mm ² active area 32 × 40 pixels

3 × 3 diode structure In-pixel amplifier

103 µm

80 µm

(25)

The Pixel

Pixel Periphery State Machine

readout state machine

VCO

&

PLL

8b/10b

encoder serializer LVDS .. .

oth er pixels

sensor CSA

comparator tune

DAC

threshold baseline source

follower

test-pulse injection

readout 2 ^nd amplifier

integrate charge

amplification

line driver

digital output AC coupling

via CR filter per pixel threshold adjustment

In-pixel amplifier

Point-to-point connection to periphery

(26)

The Periphery

Additional amplification stage Signal digitisation

8-bit time stamps Zero-suppressed readout

51 µm

7 µm

(27)

The Periphery

Pixel Periphery State Machine

readout state machine

VCO

&

PLL

8b/10b

encoder serializer LVDS .. .

oth er pixels

sensor CSA

comparator tune

DAC

threshold baseline source

follower

test-pulse injection

readout 2 ^nd amplifier

integrate charge

amplification

line driver

digital output AC coupling

via CR filter per pixel threshold adjustment

Individual pixel tuning

Characterise analogue behaviour

→ T72.2 & 3

(28)

The Analogue Behaviour

Test of general functionality HV-dependence

Analogue performance Pulse shape reconstruction SNR determination

More Details: T72.2, T72.3

(29)

The Analogue Behaviour

Data

Binomial Error Function Fit

0.58 0.60 0.62 0.64 0.66 0.68

0.0 0.2 0.4 0.6 0.8 1.0

re la tiv e nu m be r o f t rig ge rs

Threshold [V]

SNR=15

@ 1600 e ^-

Test of general functionality HV-dependence

Analogue performance Pulse shape reconstruction SNR determination

More Details: T72.2, T72.3

(30)

The MuPix State Machine

(31)

The MuPix State Machine

Pixel Periphery State Machine

readout state machine

VCO

&

PLL

8b/10b

encoder serializer LVDS .. .

oth er pixels

sensor CSA

comparator tune

DAC

threshold baseline source

follower

test-pulse injection

readout 2 ^nd amplifier

integrate charge

amplification

line driver

digital output AC coupling

via CR filter per pixel threshold adjustment

On-chip readout state machine VCO & PLL

LVDS Gbit data link

(32)

Voltage Controlled Oscillator & Phase Locked Loop

Stable working point Chip as line driver

Jitter <100 ps ( → T72.2) 1.25 Gbit/s 8b10b encoded data

Up to 30 MHits/s possible

(33)

Power Consumption

Upper limit of 400 mW cm ⁻²

Temperature gradient of 50 K ( → T75.7)

Investigation of temperature dependence ( → T72.2)

(34)

Testbeam Measurements

(35)

The Mu3e Experiment The MuPix Testbeam Results Summary & Outlook

Time Resolution

Sandwich scintillator setup

Time resolution measured to <11 ns

Time walk observed for pixel analogue behaviour

(36)

The Mu3e Experiment The MuPix Testbeam Results Summary & Outlook

Time Resolution

V

BL

MuPix7 Threshold

Range

time V

input pu lse

Compara tor R esponse ToT

Latency

MuPix7 Pulse

Threshold

small medium large

Energy-depostition

Sandwich scintillator setup

Time resolution measured to <11 ns

Time walk observed for pixel analogue behaviour

(37)

The Mu3e Experiment The MuPix Testbeam Results Summary & Outlook

Time Resolution

30 40 50 60 70 80

0 2000 4000 6000 8000 10000 12000

Trigger TimeStamp Difference Distribution for Single Events

time diﬀerence / 16 ns

Events

σ < 11 ns

Sandwich scintillator setup

Time resolution measured to <11 ns

Time walk observed for pixel analogue behaviour

(38)

Time Resolution

0 20 40 60 80 100 120

0 50 100 150 200 250

0 10 20 30 40 50 60 70 80 90

ToTtime Trigger Difference versus ToT

Latency [2,5ns]

ToT [10ns ]

Sandwich scintillator setup

Time resolution measured to <11 ns

Time walk observed for pixel analogue behaviour

(39)

The MuPix Telescope (T99.5)

µ m]

Residual of matched hit [

− 300 − 200 − 100 0 100 200 300

Entries [1/run]

0 50 100 150 200 250 10 3

×

µ m 19.8+-0.2 σ X Residual

µ m 18.3+-0.2 σ Y Residual

4 layers MuPix7 Use one as DUT

Time sorted data (T22.4)

Resolution <30 µm

Position resolved analysis

(40)

Efficiency Measurements

Threshold [V]

0.68 0.7 0.72 0.74 0.76 0.78

Efficiency

0.9 0.92 0.94 0.96 0.98

1 99 %

Noise Rate Eﬃciency

Threshold [V]

Noiserate per pixel [1/s]

0 500 1000 1500 2000 2500 3000 3500 4000

Use telescope setup

220 MeV mixed pion beam provided by PSI

(41)

Efficiency Measurements

Threshold [V]

0.68 0.7 0.72 0.74 0.76 0.78

Efficiency

0.9 0.92 0.94 0.96 0.98

1 99 %

Noise Rate Eﬃciency

Threshold [V]

Noiserate per pixel [1/s]

0 500 1000 1500 2000 2500 3000 3500 4000

Efficiencies above 99 % observed

Tuning results in sharp noise edge

Power consumption: ≈ 300 mW cm ⁻²

(42)

Crosstalk

Pixel Matrix

Digital Cells

Signal lines

(43)

Crosstalk

Row Address

0 5 10 15 20 25 30 35

Crosstalk Probability

− 4

10 − 3

10 − 2

10

(44)

Crosstalk

Row Address

0 5 10 15 20 25 30 35

Crosstalk Probability

− 4

10 − 3

10 − 2

10

(45)

Crosstalk

Row Address

0 5 10 15 20 25 30 35

Crosstalk Probability

− 4

10 − 3

10 − 2

10 Crosstalk observed

Matches signal routing

(46)

MuPix8 Prototype

MuP ix8

23mm

13mm

Submission planned for June 2016

First big chip 2 . 3 × 1 . 3 cm ²

Pixel size 80 × 80 µm ²

Higher resistivity substrate

First module prototypes

(47)

Summary

Reliable characterisation setup & frame work Very well performing chip technology

First HV-MAPS prototype with integrated readout

Many design goals already satisfied

(48)

Acknowledgments

The efficiency measurements for several power settings have been performed at the Test beam Facility at DESY Hamburg (Germany), a member of the Helmholtz Association (HGF).

We would like to thank the PSI for providing high rate test beams under excellent conditions.

We owe our SPS test beam time to the SPS team and our LHCb colleagues, especially Heinrich, Kazu and Martin.

We thank the Institut für Kernphysik at the JGU Mainz for giving

us the opportunity to take data at MAMI.

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A HV-MAPS Pixel Tracker for the Mu3e Experiment