Test beam results for neutron and proton irradiated MuPix7 prototypes

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Test beam results for neutron and proton irradiated MuPix7 prototypes

Lennart Huthfor the Mu3e collaboration Physikalisches Institut Heidelberg DPG spring meeting

March 2017

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Motivation

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Motivation

• new physics searches at low momenta and high rates requirethin and fastpixel sensors e.g. Mu3e: search forµ⁺ → e⁺e⁻e⁺

• Mu3e pushesHV-MAPS development

• AMS H18 process itself is radiation hard

• Radiation damage is not an issue for Mu3e

→Designnotoptimized for radiation hardness

• Are HV-MAPS potentially useful for LHC-like experiments?

→Perform measurements withirradiated MuPix7 prototypes

signal

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Motivation

• new physics searches at low momenta and high rates requirethin and fastpixel sensors e.g. Mu3e: search forµ⁺ → e⁺e⁻e⁺

• Mu3e pushesHV-MAPS development

• AMS H18 process itself is radiation hard

• Radiation damage is not an issue for Mu3e

→Designnotoptimized for radiation hardness

• Are HV-MAPS potentially useful for LHC-like experiments?

→Perform measurements withirradiated MuPix7 prototypes

background

Lennart Huth - huth@physi.uni-heidelberg.de (PI HD) March 2017 1

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The MuPix7

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HighVoltage - MonolithicActivePixelSensors (HV-MAPS)

(I.Peric, P. Fischer et al., NIM A 582 (2007) 876 )

• digital position and time read out

• 80 x 80µm²pixel size

• 256 x 256 pixel

• 2 x 2 cm²active size

• σ_t<14.3 ns measured

• efficiency>99.5 % measured

• 50µm thin≈0.05% radiation length

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MuPix7

• full self-triggered zero-suppressed readout running in on-chip state machine

• 1.25 GBit/s serial data output

• 125 MHz external reference clock

• 32 pixel×40 pixel with size of 103 x 80 µm²

• active area: 3.3 mm²×3.2 mm²

120 mV 60 mV 0 mV -60 mV -120 mV

0 1 2 3 4 ns

Questions addressed in the talk

• how does the test beam setup look?

• can we operate the MuPix after irradiation?

• do we see a temperature influence?

• how performs the irradiated MuPix compared to the non irradiated MuPix?

• how is efficiency, noise and time resolution changing with the dose?

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Setup and Samples

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Setup

• dry N2volume box

• gaseous nitrogen cooling

• up to 2 duts in parallel

• gas cooled down to−20^◦C

chip on carrier

with peltier element direct gas ﬂow

cooling

Beam

volume N

ﬂow 25°C 2 stage heat

exchanger -20°C 0°C

ﬂow control

dry nitrogen atmosphere

2

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Samples

CERN PS proton irradiated

• 28 MeV/c protons

• 7.8×10¹⁵p/cm²≈4.7×10¹⁵n/cm²

• 1.5×10¹⁵p/cm²≈0.9×10¹⁵n/cm²

• directly glued to a thinned PCB

• cooled with gas flow Ljubljana neutron irradiated

• 5.0×10¹⁵n/cm²

• 1.0×10¹⁵n/cm²

• 5.0×10¹⁴n/cm²

• mounted on carrier

• cooled with peltier element

All sensors tested after 1 year of annealing at room temperature

Irradiated sensors need to be cooled to<10^◦C to be operated (we used≈0-4^◦C)

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Observations & Results

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Noise based tuning - 70 V

0.0 n/cm² 1.5×10¹⁵n/cm² 1.5×10¹⁵p/cm²

TDAC

2 4 6 8 10 12 14

Column

0 5 10 15 20 25 30

Row

0 5 10 15 20 25 30 35

TDAC

0 2 4 6 8 10 12 14

Column

0 5 10 15 20 25 30

Row

0 5 10 15 20 25 30 35

TDAC

0 2 4 6 8 10 12 14

Column

0 5 10 15 20 25 30

Row

0 5 10 15 20 25 30 35

• all sensors tuned to 1 Hz noise per pixel

• over tuned pixels corrected

• flat distribution for non irradiated

• clear structure in proton irradiated

• increased pixel to pixel variations

• only 95 % of the pixels tuned!

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Efficiency and noise at HV = -60 V

Non irradiated

Threshold [V]

0.66 0.68 0.7 0.72 0.74

Efficiency

0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1

Efficiency

Noise

Noiserate per pixel [1/s]

10

102

103

Ljubljana neutron irradiated 5.0×10¹⁴n/cm²

Threshold [V]

0.66 0.68 0.7 0.72 0.74

Efficiency

0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1

Efficiency

Noise

10

102

103

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Efficiency and noise at HV = -60 V

Non irradiated

Threshold [V]

0.66 0.68 0.7 0.72 0.74

Efficiency

0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1

Efficiency

Noise

10

102

103

PS proton irradiated 1.5×10¹⁵p/cm²

Threshold [V]

0.66 0.68 0.7 0.72 0.74

Efficiency

0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1

Efficiency

Noise

10

102

103

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Effect of the HV 5.0 × 10

¹⁵

n/cm

²

Threshold [V]

0.66 0.68 0.7 0.72 0.74

Efficiency

0 0.2 0.4 0.6 0.8 1

201611_psi_carrier_5e15_eff_hpRemoved.pdf

Settings

5e15 -40V 365MeV/c 5e15 -60V 365MeV/c 5e15 -70V 365MeV/c 5e15 -85V 365MeV/c

Threshold [V]

0.66 0.68 0.7 0.72 0.74

Noiserate per Pixel [1/s]

−2

10

−1

10 1 10 102

103

104

201611_psi_carrier_5e15_noise_hpRemoved.pdf

Settings

5e15 -40V 365MeV/c 5e15 -60V 365MeV/c 5e15 -70V 365MeV/c 5e15 -85V 365MeV/c 201611_psi_carrier_5e15_noise_hpRemoved.pdf

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Comparison of the different irradiation doses

Efficiency @ 200 Hz noise per pixel

0 0.2 0.4 0.6 0.8 1

-40 V -60 V -70 V -85 V

2

cm p

0

⋅10 0.0

2

cm n

0

10⋅ 0.0

2

cm n

14

⋅10 5.0

2

cm p

15

⋅10 1.5

2

cm n

15

⋅10 5.0

2

cm p

15

⋅10 7.8

• per pixel noise rate 200 Hz

• no significant difference between carrier and direct mount

• only small decrease in efficiency up to doses of 5×10¹⁵n/p/cm²

• 1.0×10¹⁵n/cm²sensor broken (likely bonding issue)

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Time Resolution

[ns] @ 200 Hz noise per pixelσTime Resolution

0 5 10 15 20 25 30

-40 V -60 V -70 V -85 V

2

cm p

0

⋅10 0.0

2

cm n

0

10⋅ 0.0

2

cm n

14

⋅10 5.0

2

cm p

15

⋅10 1.5

2

cm n

15

⋅10 5.0

2

cm p

15

⋅10 7.8

• per pixel noise rate 200 Hz

• time difference relative to reference track hits time stamps

• plotted resolution corresponds toσof a Gaussian fit

• similar behaviour as efficiency: time resolution reduced due to dose

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Conclusion & Outlook

Conclusion

• up to 7.8×10¹⁵p/cm²irradiated samples

• 1 year annealing at room temperature

• designNOTrad. hard, but

• efficiency>90 %

• time resolution<25 ns

• increased leakage→need cooling to

< 10^◦C

• same DACs as for non irradiated at room temperature used

• results showintrinsic AMS H18 radiation hardness!

Outlook

• new MuPix8 has circular transistors

• perform similar tests

• improve cooling setup

• optimize DAC settings for irradiated samples

Efficiency @ 200 Hz noise per pixel

0 0.2 0.4 0.6 0.8 1

-40 V -60 V -70 V -85 V

p2 n² n² p2 n² p2

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BACKUP

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Comparison of different doses at −60 V

Threshold [V]

0.64 0.66 0.68 0.7 0.72 0.74

Efficiency

0 0.2 0.4 0.6 0.8 1

Comparison of different irradiations

Settings

0e0 p/cm^2 -60V 365MeV/c 1.5e15 p/cm^2 -60V 365 MeV/c 0e0 n/cm^2 -60V 365MeV/c 5e14 n/cm^2 -60V 365MeV/c 5e15 n/cm^2 -60V 365MeV/c

Threshold [V]

0.66 0.68 0.7 0.72 0.74

Noiserate per Pixel [1/s]

−2

10

−1

10 1 10 102

103

104

Settings

0e0 p/cm^2 -60V 365MeV/c 1.5e15 p/cm^2 -60V 365 MeV/c 0e0 n/cm^2 -60V 365MeV/c 5e14 n/cm^2 -60V 365MeV/c 5e15 n/cm^2 -60V 365MeV/c

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MuPix7 II

Pixel Periphery State Machine

readout state machine

VCO

&

PLL

8b/10b

encoder serializer LVDS ...

other 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

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Efficiency Studies using the MuPix Telescope II

• dut rotated

• thicker effective depletion zone higher signal - more efficient

• similar effect with higher substrate resistivity

• new prototype!

Threshold [V]

0.68 0.7 0.72 0.74 0.76

Efficiency

0.94 0.95 0.96 0.97 0.98 0.99 1

m and time cut 48 ns µ

Search Window 800

Rotation [deg]

0 15 30 45 60 m and time cut 48 ns µ

Search Window 800

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Time Resolution

−600 −500 −400 −300 −200 −100 0

Entries [1/run]

102

103

104

Time diﬀrence between hit and scintillator time [ns]

σ= 14.3 ns

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Concept

Idea: Build a tracking telescope from Mu3e detector components to test read out, synchronization and carry out test beams

Use one pixel layer as device under test (dut)