I. Time Resolution of a MCP-PMT and II. Test Infrastructure in the - - PowerPoint PPT Presentation

• I. Time Resolution of a MCP-PMT and
• II. Test Infrastructure in the Solid State Detector Lab
• M. Centis Vignali 1

Representing: CEA (Saclay), CERN, NSRC “Demokritos”, Princeton University, Thessaloniki University, USTC (Hefei) 22.02.2017 RD51 Precise Timing Workshop, CERN

1matteo.centis.vignali@cern.ch 1 / 28

The RD51 PICOSEC collaboration

Fast Timing for High-Rate Environments: A Micromegas Solution

Institutes: CEA (Saclay):

• T. Papaevangelou, I. Giomataris, M. Kebbiri

CERN:

• L. Ropelewski, E. Oliveri, F

. Resnati, R. Veenhof, S. White, H. Muller, F . Brunbauer,

• J. Bortfeldt, M. van Stenis, M. Lupberger, T. Schneider, C. David, D. Gonzalez Diaz2

NCSR Demokritos:

• G. Fanourakis

Princeton University:

• S. White, K.T. McDonald, Changguo Lu

University of Thessaloniki:

• S. Tzamarias

University of Science and Technology of China: Yi Zhou, Zhiyong Zhang, Jianbei Liu

Contributing from the RD50 collaboration:

CERN:

• M. Centis Vignali, M. Moll, and the SSD lab group (EP-DT-DD)

2Present Institute: University of Santiago de Compostela 2 / 28

• I. Time Resolution of a MCP-PMT

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Timing

∆t = t2 − t1 σ2

∆t = σ2 t1 + σ2 t2

σ2

t = σ2 J + σ2 TW + ...

Jitter The noise influences the time at which the threshold is crossed σJ = σn/dV

dt

Countermeasures: Reduce rise time Improve noise figure Time walk Variations in the amplitude influence the time at which the threshold is crossed Countermeasures: Algorithm e.g. CFD

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MCP-PMT

Microchannel plate photomultipliers MPC as amplification structure Million of microglass tubes fused in parallel 1 − 3 plates in one PMT Channel diameter 6-20 µm Vbias ≈ 3000 V Gain 104 − 106

Hamamatsu PMT handbook, chapter 10 5 / 28

Beam Test

Performed by the PICOSEC group of the RD51 collaboration CERN SPS Fall 2016 Several timing detectors Gas detectors Silicon detectors MCP-PMT used as time reference Analysis of a special run to characterize the timing reference

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Beam Test Setup

150 GeV/c muons 2 MCP-PMTs ( ˇ C light) Scope readout Trigger on PMT2 (50 mV thr)

MCP-PMTs

Hamamatsu R3809U-50/52 3.2 mm quartz window 11 mm diameter photocathode Bias 2.8 kV Gain ≈ 8 · 104

Scope

2.5 GHz bandwidth 8 bit (LSB 3.5 mV) 40 GSa/s (25 ps sampling)

Time [s] 2 − 1.5 − 1 − 0.5 − 0.5 1 1.5 2

9 −

10 × Amplitude [V] 0.1 0.2 0.3 0.4

Thanks to Stefano Mazzoni for lending one of the MCP-PMT

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Noise and Baseline

Noise Distr of all points with time < -2 ns ≈ 1.6 mV for both PMTs PMT1

Amplitude [V] 0.02 − 0.015 − 0.01 − 0.005 − 0.005 0.01 0.015 0.02

3

10

4

10

5

10

6

10

Baseline Mean (evt by evt) of all points with time < -2 ns PMT1

Baseline [V] 0.004 − 0.003 − 0.002 − 0.001 − 0.001 0.002 0.003 0.004 1 10

2

10

3

10

4

10 Time [s] 6 − 4 − 2 − 2 4 6

9 −

10 × Amplitude [V] 0.1 0.2 0.3 0.4

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Event Selection

From run using a 5 × 5 mm2 trigger scintillator: Max ampli 1 > 200 mV Max ampli 2 > 120 mV Max using parabolic interpolation Max measured from baseline

Time [s] 6 − 4 − 2 − 2 4 6

9 −

10 × Amplitude [V] 0.1 0.2 0.3 0.4

Max ampli distribution PMT1, PMT2

Amplitude [V] 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 1 10

2

10

3

10

4

10

Components: Poisson distribution of number of photoelectrons Partial collection of ˇ C light

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Data Interpolation

Signal sampled every 25 ps Linear interpolation of 2 points to determine crossing time

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Rise Time 20% 80%

Average rise time 116 ps PMT1, PMT2

Rise time [s] 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2

9 −

10 × 1000 2000 3000 4000 5000

Same rise time for both PMTs Correlation rise time amplitude PMT1 (no amplitude cuts)

1000 2000 3000 4000 5000 6000 Amplitude [V] 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 Rise time [s] 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

9 −

10 ×

Rise time independent of amplitude

Time [s] 6 − 4 − 2 − 2 4 6

9 −

10 × Amplitude [V] 0.1 0.2 0.3 0.4

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Timing using Leading Edge Discriminator

Resolution → std dev of ∆t = t2 − t1 Resolution map

Thr 1 [V] 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1 0.11 Thr 2 [V] 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1 0.11 t [s] ∆ Std Dev 26 28 30 32 34 36 38

12 −

10 ×

Max ampli at least 5% higher than thr Diagonal of the 2d plot

Thr [V] 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1 0.11 t [s] ∆ Std Dev 5 10 15 20 25 30 35

12 −

10 ×

∆t distribution, thr = 30 mV

t [s] ∆ 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

9 −

10 × 100 200 300 400 500 600

0.30 ps, 9855 events ± = 24.02 σ 0.30 ps, 9855 events ± = 24.02 σ

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Timing using Constant Fraction Discriminator

Resolution → std dev of ∆t = t2 − t1 Resolution map

t [s] ∆ Std Dev 8 10 12 14 16 18 20 22 24

12 −

10 × CFD frac 1 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 CFD frac 2 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

Reduction of time walk Diagonal of the 2d plot

CFD frac 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 t [s] ∆ Std Dev 2 4 6 8 10 12 14

12 −

10 ×

∆t distribution, CF = 0.45

t [s] ∆ 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

9 −

10 × 200 400 600 800 1000 1200 1400 1600 1800 2000

0.22 ps, 9855 events ± = 7.66 σ 0.22 ps, 9855 events ± = 7.66 σ

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Timing as a Function of Amplitude

Resolution → std dev of ∆t = t2 − t1 Resolution map

t [s] ∆ Std Dev 2 4 6 8 10 12 14 16 18 20

12 −

10 × Amplitude 1 [V] 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 Amplitude 2 [V] 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

CFD with CF = 0.45 No amplitude cuts “Holes” due to low statistics Diagonal of the 2d plot

Amplitude [V] 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 t [s] ∆ Std Dev 2 4 6 8 10 12 14 16 18 20

12 −

10 ×

The resolution improves with amplitude

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Transit Time Spread for MCP-PMT

Variations in the time it takes for an electron to move from the photocathode to the MCP σTTS ∝ TTS/ √ N N → number of photoelectrons ⇒ σTTS

∆t

∝

• 1

N1 + 1 N2

Conversion coeff to number of photons from a different run

1/N1 + 1/N2 0.2 0.4 0.6 0.8 1 1.2 1.4 t [s] ∆ Std Dev 2 4 6 8 10 12 14 16 18 20

12 −

10 ×

Outliers probably due to low statistics

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Leading Edge Interpolation

Linear interpolation of points between 20% and 80% of ampli LED thr = 30 mV

t [s] ∆ 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

9 −

10 × 200 400 600 800 1000

0.21 ps, 9855 events ± = 13.61 σ 0.21 ps, 9855 events ± = 13.61 σ

Std dev 2 pt interpolation: 24.0 ps CFD CF = 0.45

t [s] ∆ 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

9 −

10 × 200 400 600 800 1000 1200 1400 1600 1800 2000

0.22 ps, 9855 events ± = 7.78 σ 0.22 ps, 9855 events ± = 7.78 σ

Std dev 2 pt interpolation: 7.7 ps LED more affected than CFD due to different thr

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Leading Edge Interpolation

Linear interpolation of points between 20% and 80% of ampli LED thr = 30 mV

t [s] ∆ 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

9 −

10 × 200 400 600 800 1000

0.21 ps, 9855 events ± = 13.61 σ 0.21 ps, 9855 events ± = 13.61 σ

Std dev 2 pt interpolation: 24.0 ps Extrapolation to 0 of interpolation

t [s] ∆ 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

9 −

10 × 200 400 600 800 1000 1200 1400 1600 1800

0.38 ps, 9855 events ± = 9.73 σ 0.38 ps, 9855 events ± = 9.73 σ

Improvement wrt LED due to partial time walk correction

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• II. Test Infrastructure in the Solid State

Detector Lab

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Silicon Detectors

Solid state ionization detector Mono-crystalline Si Rectifying junction in reverse bias Mean ionization energy: 3.6 eV/eh Typical thickness, 300 µm typical Signal ≈ 24000 e− in 300 µm Fast signals, O(10 ns)

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Transient Current Technique (TCT)

Measure i(t) to investigate sensor’s electric field and charge collection iind = n · q0 · v · EW = nq0µE d EW = 1/d v = µ · E Produce eh pairs using a pulsed laser Red laser → short absorption depth (few µm) → one type of charge carriers drifts Infrared laser → long absorption depth (≈mm) → similar to charged particle signal Read out the signal using an oscilloscope

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TCT Example (Non-irradiated Diode)

Holes drift (red top) Electrons drift (red bottom)

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Edge TCT

In irradiated sensors trapping of e/h reduces the signal during drift → less signal to study the E field Edge illumination Use the first part of the i(t) pulse to extract information Scan the sensor thickness by moving the laser spot Drift velocity profile for an irradiated detector (Φeq = 5 · 1015 cm−2)

From: Investigation of Irradiated Silicon Detectors by Edge-TCT, G. Kramberger et al., IEEE 2010 22 / 28

TCT setup

Red (600 nm) and infrared (1064 nm) laser 200 ps pulse Laser focus ≈ 10 µm Front, back, and edge illumination Current amplifier 2.5 GHz, 20 GSa/s oscilloscope Reference diodes to monitor laser intensity Temperature control Translation stages

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TCT setup

Red (600 nm) and infrared (1064 nm) laser 200 ps pulse Laser focus ≈ 10 µm Front, back, and edge illumination Current amplifier 2.5 GHz, 20 GSa/s oscilloscope Reference diodes to monitor laser intensity Temperature control Translation stages

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TCT for Timing

Use signal from reference diodes as time reference Alternatively, use second detector for reference To be tested in the next weeks

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Two Photon Absorption TCT

Point-like charge carrier generation 3D sensor scan Use wavelength for which Si is transparent e/h pair generation through virtual states Photons densly packed in space and time High intensity femtosecond laser Measurement performed at the SGIKER laser facility in Bilbao Application ongoing to acquire components for one setup

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Summary SSD Lab Test Infrastructure

Current infrastructure used to characterize irradiated and non-irradiated Si detectors Several parameters investigated No time to show all the setups Extension to timing measurement in the next months Lab setups constantly maintained and upgraded

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Summary MCP-PMT Timing

Implemented different timing algorithms to estimate the timing resolution of the 2 MCP-PMT system The result depends on the used algorithm The best resolution is obtained using a CFD The results are similar to the ones of Inami et al. NIM A560 303-308 (2006)

Resolution [ps] Single PMT resolution [ps] Algorithm 2 pt inter Leading edge inter 2 pt inter Leading edge inter LED thr = 30 mV 24.0 13.6 17.0 9.6 CFD CF = 0.45 7.7 7.8 5.4 5.5 Extr 0

• 9.7
• 6.9

The resolution of a single MCP-PMT is obtained by dividing the result by √ 2

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Backup Material

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Max Ampli vs Radius

From different run Using tracking information

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Absorption Depth in Si

From: http://www.pveducation.org/pvcdrom/materials/optical- properties-of-silicon

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IV/CV

Current-Voltage Dark current Noise Power consumption Capacitance-Voltage Capacitance Depletion voltage Doping Setup Temperature controlled chuck Probe needles Voltage source Ammeter LCR meter

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