ALICE upgrades - Time Projection Chamber - CERN Indico
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Time Projection Chamber
GEM-based read-out chambers
Inner Tracking System
Monolithic Active Pixel Sensors
ALICE Read-out & computing
upgrades O2, FLP, EPN, PDP
2021 2022 2023
Future upgrades
2024 2025 2026 2027 2028 2029 2030 2031 2032 2033
LS 2 Run 3 LS 3 Run 4 LS 4 Run 5
ITS3 FoCal ALICE 3
• thinned (~25 µm) silicon sensors • silicon pixel + pad read-out • large area coverage sensors
→ bendable detectors → high-resolution energy → all-silicon tracker
measurement of photons
• stitching • cylindrical large sensors
→ wafer-sized sensors → retractable inner tracker
• silicon timing (σ ~20 ps)
→ particle identi cation
Various projects on di erent timescales, open to participation
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FoCal
A novel concept for forward calorimetry
FoCal-H
FoCal-E
3.4 < η < 5.8 Flange
• Physics goal:
Saturation/shadowing at low-x with direct photons in pp/p-Pb
Contact
• Focal-E:
high-granularity Si-W calorimeter with pixel + pad read-out
• FoCal-H:
conventional sampling calorimeter
C. Loizides
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The ALICE Forward Calorimeter
FoCal-E module
Longitudinal pro le (2γ showers) Trans. pro le
18 pad + 2 pixel layers
Full FoCal-E: 22 modules
• Main challenge: Separate γ/π0 at high energy
• Two photon separation from π0 decay (pT=10 GeV, η=4.5) ~5mm
• Two readout granularities
• PAD (LG) layers: granularity 1x1 cm2, analog readout
Letter-of-Intent: CERN-LHCC-2020-009 • PIXEL (HG) layers: 30x30 µm2 digital readout
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FoCal: recent news
New sensors: 8x9 geometry p-type
pedestal + signal
• Construction of prototype for test beam 2021
• new pad sensors acquired, being tested in beam
(ELPH Japan)
• readout PCB: rst prototypes acquired; tests ongoing
• construction and test of pixel modules
ELPH beam test: 0.9 GeV positrons
• Pixel prototype: EPICAL-2
(Feb 2021)
• new results from DESY test beam
• high-energy test at SPS
Number of pixel hits Energy resolution
Presentation at ALICE Week
Response simulations
5 with AllPix2 LCWS talks: T Rogoschinski, F Pliquett
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FoCal timeline
• 2021: Test beam at SPS
• validate performance with small-scale prototype
• new pad sensors+readout
• new pixel modules
• rst HCAL prototype Test beam setup
• 2022: Technical design report
• full module design; integration studies
• HCAL design
• additional physics performance studies
• 2023-2026: Construction
Integration challenge:
compact design
• 2026/2027 (LS3): Installation with electronics and cooling
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ITS3
From stave-based inner barrel to truly cylindrical layers ITS3
ITS2
• Improve performance by
• moving closer to the interaction point
Contacts
• reducing material budget
• Replace Inner Barrel with truly cylindrical layers (ITS3)
• requires low-power, wafer-scale, bendable MAPS
(65 nm ISC, stitching, thinning) A. Kluge M. Mager
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Sensor development
• First MLR submission (TowerJazz 65 nm ISC) out in 2020
• transistor test structures
• analog building blocks (band gaps, LVDS drivers, …)
• various diode matrices
• digital test matrices
• Testing and characterisation in preparation,
end-of-line ~May
• dedicated test system
• radiation hardness
• charge collection
• mechanical properties
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In-beam characterisation
• Operation of bent ALPIDEs established
• Several techniques for interconnections
in several laboratories
• Several test beam campaigns with bent ALPIDEs
• performance of bent ALPIDE sensors con rmed
(no performance degradation observed)
• ALPIDE telescope to be extended
for testing of µITS
Presentation at ALICE Week
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Mechanics
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Super-ALPIDE µITS3 Engineering model
• large-scale sensor • Individual ALPIDEs • Non-functional wafers
with individual ALPIDEs on support structure in target geometry
with target geometry
• FPC instead of stitching • Testing mechanical stability
10ITS3 timeline
NB: does include single, earlier TDR
old MPW2, too submission
Sensor MLR1 MLR2 ER1 ER2 ER3
(submissions) 65nm tech. test 65nm pixel opt. building blocks full-scale final chip
stitching
300mm 300mm 65nm
Thinning full-scale
ALPIDE chips dummy prototype
Bending prototype
wafers wafers
LS3
Mechanics BM EM QM FM
Cooling material selection half-barrel
Beampipe market tender beam pipe execution of
survey qualification pre-installation
purchase contract
samples
2019 2020 2021 2022 2023 2024 2025 2026 2027
11ALICE 3
A next-generation heavy-ion experiment
• Heavy-ion physics programme beyond Run 3+4 requires
→ qualitative steps in luminosity and detector performance
→ novel concepts
• Idea developed within ALICE in the course of 2018/19
ALICE Upgrade Coordination
Jochen Klein (CERN)
Marco van Leeuwen (Nikhef)
• discussed at the heavy-ion town meeting Heavy Flavour
(CERN, Oct 2018) Gian Michele Innocenti (CERN)
ALICE 3 LoI Working Groups & Coordinators
• Expression of Interest as input to EPPS Update Dileptons and Photons
(Granada, May 2019) Klaus Reygers (University of Heidelberg)
Michael Weber (Vienna)
• taken up in EPPS Update deliberation document Simulation and Performance
Matteo Concas (INFN Torino, CERN)
Roberto Preghenella (INFN Bologna)
• Concrete activities towards LoI since beginning of 2020 Layout and Outer Detectors
Werner Riegler (CERN)
• Physics and detector working groups formed
• Letter of Intent in preparation for submission by end of Time of Flight
Andrea Alici (INFN Bologna), Stefania Bufalino (Politecnico
2021 Torino), Angelo Rivetti (INFN Torino)
4D Tracking
Alessandro Grelli (Nikhef),
Magnus Mager (CERN)
12Fundamental questions
• What are the mechanisms of hadron formation in QCD?
• new types of hadrons found at LHC: new states, tetraquarks, …
• o ers new angles to explore hadron production, in particular multi-quark states
• connection to di erent areas of theory (ab initio calculations, lattice, …)
• Can we prove the realisation of chiral symmetry restoration (fundamental property of QCD)?
• electromagnetic probes from plasma phase
precision measurements of di-lepton spectra
• Are there violations of fundamental properties of quantum eld theories?
• probe predictions from tree-level exact Low theorem (emission of soft photons)
• Is there new physics (BSM)?
• phase space inaccessible by other experiments
• use heavy-ion collisions as a tool
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fiDetector concept
Fast and ultra-thin detector with precise tracking and particle identi cation
• Ultra-lightweight silicon tracker with excellent vertexing
• Fast to pro t from higher luminosity (also with nuclei lighter than Pb): 50-100x Run 3/4
• Particle Identi cation: TOF determination ( 20 ps time resolution), Cherenkov, pre-shower/calorimetry
• Kinematic range down to very low pT: 50 MeV/c (central barrel), MeV/c forward (dedicated detector)
• Large acceptance barrel + end caps Δη = 8
4d tracker of ~100 m2
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fiTracker
• Tracker geometry for performance studies (with B = 0.5 T) Leveraging ITS3
• Rin ~ 5 mm, Rout ~ 1m, L ~ 2.8 m (η ~ 1.75), Nlayers ~ 12
(assumes retractable inner tracker) • Additional R&D needed for
• Material budget X/X0: 0.1/1 % (inner/outer layers) • Timing capabilities (4d tracking)
• instrumented area: barrel ~ 53 m2, disks ~ 27 m2
• Distribution of timing reference
• Various detectors for particle identi cation under study • Large area coverage
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fiIdenti ed particles: electrons and hadrons
TOF with σTOF = 20 ps
• Electron identi cation
• Low-mass di-electron spectra: 50 MeV/c < pT < 3 GeV/c
need hadron rejection > 1000x with electron e ciency > 80 %
• Electrical conductivity: 10 MeV/c < pT < 100 MeV/c:
electron ID in forward region (p boosted by x10 at η ~3)
• Hadron identi cation
• HF decay chains: 50 MeV/c < pT < 5 GeV/c
> 3 sigma separation of π/K/p
Example e/π pT ranges
• Low to intermediate pT: electron+hadron ID with silicon-TOF
• Higher pT: two solutions under study
• RICH: hadron + electron ID up to several GeV
• Pre-shower:
• electron-ID up to high pT
• challenge: electron ID around ~ 500 MeV — performance studies ongoing
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ffiR&D challenges
• Inner tracker
• minimal distance from IP requires retractable detector
• ultra-thin layout: exible wafer-scale sensors (MAPS)
• position resolution O(1 µm) requires small pixel pitch
• Outer tracker
• large areas to instrument: develop cost-e ective sensors
• low material budget requires low-weight support and services
• Time of Flight
• large areas to instrument: develop cost-e ective sensors
• TOF resolution < 20 ps needed on the system level
requires advances both on sensors and microelectronics
• Cherenkov
• aerogel RICH: large area of single photon e cient sensors (visible light)
(SiPM, MAPS?, LAPPD, …)
• or develop other geometries, e.g. DIRC, for large occupancy?
• Photon detection at low pT
• develop system for very low pT photons with pointing resolution
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ffiDiscussion: areas for collaboration
• Wide spectrum of opportunities for collaboration:
• Micro-electronics
• monolithic active pixel sensor development (ITS3, ALICE 3)
• fast timing detectors (ALICE 3)
• Sensor characterisation
• Cooling and integration for high-density systems (FoCal, ITS3, ALICE 3)
• Detector construction/assembly (FoCal)
• Firmware development for readout, trigger etc
• Run 3 and/or run 4 (ALICE 2, ITS3, FoCal)
• Software/computing infrastructure: see talks Andreas, Vasco
• Physics performance studies (ITS3, FoCal, ALICE 3)
• Form teams around activities
• Engineers: (small) team to keep critical mass A team has at least two people
who attend regular (weekly) meetings etc
• Graduate students + (experienced) supervisor
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