Large pixel SiPMs for single photon detection in the new LHCb large - - PowerPoint PPT Presentation
PIXEL2018 International workshop on Semiconductor Pixel Detectors for Particles and Imaging Large pixel SiPMs for single photon detection in the new LHCb large area scintillating fibre tracker Olivier Girard , Maria Elena Stramaglia, Guido
PIXEL2018 International workshop on Semiconductor Pixel Detectors for Particles and Imaging
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Module assembly on frame
3 3 Tracking station 12 detection layers 320 m2 total area 2× 3 m 2× 2.5 m SciFi module fibre mats + mirrors Read-out box SiPMs, cooling, electronics mirrors
3 3 Tracking station 12 detection layers 320 m2 total area 2× 3 m 2× 2.5 m SciFi module fibre mats + mirrors Read-out box SiPMs, cooling, electronics mirrors
3 3 Tracking station 12 detection layers 320 m2 total area 2× 3 m 2× 2.5 m SciFi module fibre mats + mirrors Read-out box SiPMs, cooling, electronics mirrors
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Signal =
Injection at mirror DV=3.5V
X = 1.35 mm X/X0 = 0.41% Energy deposit × scint. light yield × light capture × light attenuation × photon det. eff.
VELO upgrade
Signal = O(10k) e- Noise = O(200) e-
Collected
X = 220 μm X/X0 = 0.23%
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Signal =
Injection at mirror DV=3.5V
X = 1.35 mm X/X0 = 0.41% Energy deposit × scint. light yield × light capture × light attenuation × photon det. eff. → Amplification needed!
VELO upgrade
Signal = O(10k) e- Noise = O(200) e-
Collected
X = 220 μm X/X0 = 0.23%
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Signal =
Injection at mirror DV=3.5V
X = 1.35 mm X/X0 = 0.41% Energy deposit × scint. light yield × light capture × light attenuation × photon det. eff. → Amplification needed! Noise Collected from 2-3 ch. = 2-3 × 104 pixels
VELO upgrade
Signal = O(10k) e- Noise = O(200) e-
Collected
X = 220 μm X/X0 = 0.23%
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Signal =
Injection at mirror DV=3.5V
X = 1.35 mm X/X0 = 0.41% Energy deposit × scint. light yield × light capture × light attenuation × photon det. eff. → Amplification needed! Noise Collected from 2-3 ch. = 2-3 × 104 pixels Radiation environment Fibres: max 30kGy SiPMs: 5·1011 neq/cm2
VELO upgrade
Signal = O(10k) e- Noise = O(200) e-
Collected
X = 220 μm X/X0 = 0.23%
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Customised SiPM array produced by Hamamatsu (S13552)
Large pixels Opaque trenches Adjusted quenching resistor
32.54 × 1.625 mm2
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Overlap of pulses (high signals) Cooling (÷2 per 10°C) Short integration time Clustering
0.41mm2 channel DV=3.5V T=-40°C 4.5V 3.5V 2.5V neutrons protons
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DV=2V T=-40°C
SPIROC
due to the high dark current
PACIFIC
DV=3.5V T=-40°C 6∙1011 neq/cm2 Non-irradiated
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“Light yield” Noise ±4% up to 6∙1011 neq/cm2
efficiency
DV=3.5V T=-40°C
SPIROC
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Timescale during LS2 in 2019-2020 Goal extend physics reach with:
Higher luminosity (5×) Better trigger efficiency for a wide
range of decay channels
Design for 50 fb-1 integrated
luminosity Run1+2 (2011-now): 7 fb-1 Detector changes
40 MHz read-out + flexible trigger (in
software)
Detector hardware: cope with
increased occupancy and read-out rate Downstream tracker is replaced: silicon strips (IT) + straw tubes (OT) → scintillating fibre (SciFi) tracker modules
High hit detection efficiency Fine granularity Low mass (homogenous distribution)
17 2× 3 m 2× 2.5 m
µm) arranged in mats
Silicon PhotoMultipliers (SiPMs) for a total of 524k read-out channels
6 layers 1.35 mm
Tracking station 4 detection layers (stereo angles 0, ±5°) SciFi module fibre mats + mirrors Read-out box SiPMs, cooling, electronics mirror s
30 kGy 5·1011 neq/cm2
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In the central region: 30 kGy
Dominated by neutrons Neutron shielding between SciFi tracker
and calorimeter
Fluence expected: 5·1011 neq/cm2
Reduced transparency of the fibres Increase in SiPM noise
M1 replaced by polyethylene with 5% boron (10-20cm thick) Calorimeter SiPMs
SciFi tracker Neutron fluence: ratio
"𝑥𝑗𝑢𝑖 𝑡𝑖𝑗𝑓𝑚𝑒𝑗𝑜" "𝑜𝑝 𝑡𝑖𝑗𝑓𝑚𝑒𝑗𝑜"
30 kGy 50 to 100 Gy + neutrons
SiPMs
Total ionising dose at the end of the lifetime of the SciFi tracker [Gy]
SiPMs F i b r e s
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Signal time spread: scintillator
decay time and light transport
Attenuation length: ~ size Large size: flatness and
Radiation environment (fibres and
SiPMs): detection efficiency
SiPM cooling (-40°C)
Kuraray SCSF-78MJ blue emitting fibre
Cold box cross-section
SiP M 3D-printed Ti cooling pipe Cold-warm feed-through FE electronics connection Cold box isolation Fibres 3D-printed Ti cooling pipe Enclosure Vacuum insulated distribution pipes
SiPM gluing to cooling pipe and optical
alignment
3D printed Ti cooling pipe with alignment
pins, thermal expansion and isolation are the main challenges
Integration into a vapour tight cooling
Cooling with single phase liquid chiller
(Novec or C6F14)
Front-end electronics with custom read-out
chip (Pacific)
Zero suppression (clusterisation) based on 3
threshold sampling
Optical transmission, zero suppression on
FPGA and GBT transmission
Common off detector electronics TELL40
20 Multi-channel SiPM with feed-through Cooling pipe Enclosure Vacuum insula- ted connections
Cold- box
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IEEE NSS MIC 2017
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23 O(1 - 10 mm) O(10 - 100 µm)
HPK, thin metal film RQ KETEK, Custom implementation HPK, MPPC
Overlap of pulses (high signals) Reduced by cooling (÷2 per 10°C) and
short integration time window
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Acerbi, 2015
Avalanches generated ~simultaneously DiXT, DeXT, AP Limits the operation range (and
therefore PDE)
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current and pulse frequency under illumination
noise (and dark)
3.5%
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PDE ∆𝑊 = 𝑐 ∙ 1 − 𝑓−∆𝑊/𝑏 𝑏 𝜇 > 𝑏(𝜇)
QE∙FF P01 For p-on-n structure:
SCSF-78MJ emission spectrum
~50% @ peak
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𝜐d = 𝑆d ∙ 𝐷d + 𝐷Q 𝜐short = 𝑆load ∙ 𝐷tot 𝜐long = 𝑆Q ∙ 𝐷d + 𝐷Q
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Pulse shape Correlated noise RQ DCR Gain PDE VBD VBD Gain PDE Gain NCR
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Oscilloscope
Pulse shape Amplifier Light injection Cooling
Measurements on single channel Light source Monochromator Fibre Diffuser Calibrated photodiode SiPM PDE
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DiXT DeXT AP VBD
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H2017 lot1 DV = 4.8V H2017 lot1 Delayed pulses
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𝑓−𝑢∙𝑔DCR 𝐻 = 𝑉𝑒𝑢 1𝑄𝐹 𝑆load ∙ 𝐻Amp ∙ 𝑓 ~ -6% High DCR DiXT detection
array read out at 40MHz
electronics shaping (here: SPIROC)
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Pedestal
DV = 3.5V DV = 3.5V
Dark pulses Correlated noise
Seed thrs = 2.5PE
length tint
function of tint
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Dark spectrum NCR vs seed NCR vs tint 𝜐int
bias = 𝛽 ∙ 𝑊 bias − 𝑊 BD 𝜁
⇒ d ln 𝐽 d 𝑊
bias −1
∝ Δ𝑊
region
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Cooling
38 Custom machine High quality mat: 2.5 m × 13 cm, 6 fibre layers Total of 1200 mats Four production centres (including EPFL) Optical scanner Uniform light yield (β- source) Special modules with beam pipe cut out 5 m × 53 cm Rigidity: honeycomb panels Cooling distribution Neutron shield Cabling
Related posters:
assurance of scintillating fibre modules for the LHCb upgrade.
Optical properties Mechanical specifications
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an area with controlled humidity and temperature
black 25 μm thick capton foil (both sides, ensures light tightness) and end piece glueing
and unforming
milling machine (polishing with a diamond head)
glueing
and β-source (light yield homogeneity)
Heidelberg and Nikhef for module assembly + integration of SiPMs, cooling and FE electronics
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properties:
specification ensuring high quality fibre mat production
identified with laser micrometer scanner
Detection and measurement of defects Fibre spool 12.5 km Target spool Bump shrinking by heating 100°C Ø 350 µm F ≈ 1 N Example: Before 415 µm → After 337 µm
Fiber Bumps larger than 500 µm must be cut away and the fibre re-glued (~15 min, 1-2×/spool). Fibre scanner: 3h30/spool
Bump shrinking is fully automatic and it preserves fibre strength, cladding and 85% light transmission.
Four production centres: RWTH Aachen and TU Dortmund (DE), EPFL
Custom winding machine produced by an industrial company (one per
winding centre)
Fibre mat of 2.5 m length × 13 cm width, 6 fibre layers with a total of 7
Mat winding takes 4h (1 per day)
41 Visual monitoring to detect fibre jumps Alignment pin groove in the wheel, filled with glue during winding, allows precision positioning at later production steps ~1200 mats required for the SciFi tracker Aimed production rate: 4 mats/week/site
Fibre spool Threaded Winding wheel Ø 82 cm Fibre tensioning system Linear axis for precision positioning
Checks for distorted or missing
fibres with an automated optical scanning and fibre detection
Measurement of light yield with an
electron source
42 Casted fibre mat End piece Scanner SiPM die gap, partially recovered by neighbouring channels