Summary of Detector Technology Session

11th FCC-ee workshop, Jan. 11th 2019W. Riegler, CERN

ALICE TC, convenor of FCC-hh detectors and experiments

Very stimulation session with lots of discussion …

FCC-hh reference detector

No field return yoke for FCC-hh reference detector

I learned that detector ideas without magnet yoke for FCC-ee are ‘not very popular’ due to high sensitivity of electron beam to stray fields of any sort.

An FCC-ee detector has to be ready in 2038 at the earliest i.e. in 20 years from now.

It does not make sense to go into detailed engineering designs of FCC-ee detectors at this moment. This should be done in 2025 at the earliest.

We should use the next 5 years to think about general detector concepts and principles.

We should investigate the tracking performance with basic tools and use full simulation/reconstruction etc. for benchmark tests and not for tracker optimization.

In addition there will (hopefully) be significant advances in technology within the upgrades of the LHC detectors and other experiments.

E.g. detectors and sensors developed for Heavy Ion Physics are very well suited for application to e+e- colliders. The requirement of excellent momentum resolution and secondary vertex resolution for very low pt together with moderate radiation levels for HI physics match well the requirements for e+e- detectors.

General Thoughts

ALICE in Run 3 and Run 4

ALICE strategy for Run 3 + Run 4:

• 50 kHz Pb-Pb interaction rate (now <10 kHz)

• Experiment upgrades (LS2)

• Collect LPb-Pb > 13 nb-1

ALICE physics goals

• Heavy-flavour mesons and baryons (down to very low pT) mechanism of quark-medium interaction

• Charmonium states dissociation/regeneration as tool to study de-confinement and medium temperature

• Di-leptons from QGP radiation and low-mass vector mesons χ symmetry restoration, initial temperature and EOS

• High-precision measurement of light and hyper-nuclei production mechanism and degree of collectivity

• Need MB readout at highest possible rate no dedicated trigger possible

Tracking and PID performance (and radiation requirements) for HI physics matches closely the specs for FCC-ee

Trigger and DAQ

ALICE will write the 50kHz of PbPb collisions to storage without any selective trigger. The data will be ‘compressed’ and each event is written to permanent storage.

Each PbPb collision has around 6000 charged tracks.

Since the FCC-ee has a maximum collision rate of 130kHz at the Z, with only around 20 charged tracks per collision, the track rate (data rate) for FCC-ee is a factor 100 smaller than for ALICE PbPbin Run3.

It is clear that one doesn’t have to think about Trigger and DAQ for FCC-ee at this point, but just about the most efficient way to send the data off the detector (low mass, low power data links).

FCC-hh Volume 3

FCC-ee Volume 2

Tracker Material 11% X0 Barrel20% X0 Forward

CLD Detector and IDEA detector proposal

Very different concepts …Excellent basis for a good discussion on the essential features.

Basic formulas for: • momentum resolution• angular resolution (ϴ, ϕ)• Impact parameter resolution (d0, z0 )

for N+1 equidistant measurement planes

Basic formulas for tracking

Basic Formulas

Eq. 47, 10 deg. (mult. scattering)

Eq. 47, 90 deg., (mult. scattering)

Eq. 45, 10 deg (resolution)

Eq. 45, 90 deg. (resolution)

CLD Momentum ResolutionTalk by Emilia

Very easy way to calculate tracking performance

• Very easy way to find all track parameter resolutions for any geometry.

• For g(x) one can also use a template track shape calculated from numerical integration in a non-uniform magnetic field e.g. muons through the yoke …

• Dead material in between layers can be included by assuming a tracking layer with very large (infinite) spatial resolution such that it does not enter the fit.

Covariance Matrix for the parameters:

One should make it mandatory to superimpose these analytic results to all simulation plots !

Volume 2 FCC-ee

IDEA Detector

X0=1405m, dtot/X0=1.6m/1405m =0.0011, dpt/pt MS limit should be dpt/pt=0.00026 ?

CLD

MS limit ?

Would be very interesting to understand which contribution comes from multiple scattering and which comes from position resolution …

X0 of air 304m 1.7m =0.0056 X0

1.7m zero mass perfect resolution tracker with infinite number of detector planes in air

1.7m zero mass perfect resolution tracker with 3 detector planes in air

1.7m perfect resolution tracker with 3 detector planes of 0.003X0 each in air

From discussions with Giovanni ….

For the future we can expect detectors with excellent time resolution, 10ps seems a realistic goal.

For TOF path of 2m a time resolution of 10ps we have3σ π-K, K-p, π-p separation up to 5/8.4/9.8 GeV/c

What is the momentum range of interest ? How important is it ?

Particle Identification, TOF, dE/dx

π-KK-p

π-p

π-pK-p

π-K

Volume 2 FCC-eeIDEA detector

In addition to the questions of momentum and dE/dx resolution there are a few principle points.

Having several layers of silicon sensors provides significant redundancy. If one module in a single layer fails there is only a very small impact on the tracking performance.

For the TPC there is zero redundancy. If a chamber fails there is a hole in the acceptance. Stable TPC operation was achieved in the past, but 100% operational efficiency for all chambers is a significant requirement.

Also wire chambers with very large numbers of wires have been built and operated, but still, the breaking of a single wire can cause significant downtime and needs some tools for wire replacement.

Calibration is also a significant effort for gas detectors due to changing temperature and pressure conditions. This should be specifically taken into consideration when talking about the extreme requirements on measurement precision.

For silicon detectors there is very good experience with long term alignment stability from the LHC …

silicon vs. gas detectors

Stability of the momentum scale ??

The high granularity of ECALs proposed for e+e- detectors results in significant cost, e.g. almost 50% of the entire detector cost for the CLIC detector:

Calorimetry

What is the performance impact for a larger granularity, more standard e.g. scintillator based ECAL ?

Would LArg be an effective alternative ? There is some R&D on lightweight cryostat materials such that the impact of this additional material in front of the calorimeter might be significantly reduced (see talk by M. Aleksa).

Possibly even a thin coil in front of the ECAL would not even pose a problem, as proposed for the IDEA detector(see presentation by Herman Ten Kate).

W. Riegler

LAr Calorimetry for FCC-ee

Martin Aleksa

• Introduction: LAr Calorimetry at LHC• Calorimetry of the FCC-hh Reference Detector • Requirements for FCC-ee Calorimetry – Would LAr Calorimetry Work?• Conclusions & Outlook

Based on Material from the FCC CDR Summary Volumes (https://indico.cern.ch/event/750953/) and Studies by the FCC-hh Calorimetry Group (https://indico.cern.ch/category/8922/) January 9, 2019 11th FCC-ee Workshop — M. Aleksa (CERN) 32

ATLAS LAr EM Calorimeter

11th FCC-ee Workshop — M. Aleksa (CERN)January 9, 2019 33

|η|<3.2

tdrift ≈ 450 ns

E

Incident electrons create EM showers in Pb(X0=0.56cm) and LAr gaps (X0=14.2cm)

secondary e+ and e- create e-–ion pairs in LAr (W=23.3eV)

Ionized electrons and ions drift in electric field (2kV for 2mm gaps in barrel) and induce triangular signal (≈450ns e- drift time)

Sampling calorimeter – with Pb absorbers and active LAr gaps (2mm in barrel,

1.2 – 2.7mm in endcap)

Advantages of liquid argon (LAr) as active material– linear behavior

– stability of the response over time

– radiation tolerance

Advantages of accordion geometry– it allows a very high η-φ granularity and longitudinal

segmentation (PS, L1, L2, L3)

– it allows for very good hermeticity since HV and signal cables run only at the front and back faces of the detector

– it allows for a very high uniformity in φ

s (E)

E=

10%

EÅ

0.2

EÅ 0.2%

L1

PS or L0

L2

L3

Design resolution:

A Possible FCC-hh Detector – Reference Design for CDR

11th FCC-ee Workshop — M. Aleksa (CERN)January 9, 2019 34

• During last years converged on reference design for an FCC-hhexperiment

• Radiation simulations

• Demonstrate in the CDR document, that an experimentexploiting the full FCC-hhphysics potential is technically feasible

• Input for Delphes physics simulations

• Room for other ideas, other concepts and different technologies

• See FCC CDR Summary Volumes– https://indico.cern.ch/event/750953/Forward detectors

up to η=6Barrel HCAL: σE/E≈50%/√Ē⊕3%

Barrel ECAL: σE/E≈10%/√Ē⊕0.7%

Tracker: σpT/pT≈20% at 10TeV (1.5m radius)

Central Magnet:B=4T, 5m radius

23m

9m

Muon System: σpT/pT≈5% at 10TeV

FCC-hh Electromagnetic Calorimeter (ECAL)

11th FCC-ee Workshop — M. Aleksa (CERN)January 9, 2019 35

ZOOM

• Compared to ATLAS, FCC-hh Calo needs finer longitudinal and lateral granularity– Optimized for particle flow– 8 longitudinal compartments, fine lateral granularity – Granularity: Δη x Δφ ≈ 0.01 x 0.01; first layer Δη x Δφ ≈ 0.0025 x 0.02 ~2.5M channels

• Possible only with straight multilayer electrodes (no accordion)– Active material LAr– Straight absorbers (Pb + stainless steel sheets), 50∘ inclined with respect to radial direction – Readout and HV on straight multilayer electrodes (PCBs, 7 layers, 1.2mm thick)– Sampling fraction changes with depth fsampl ≈ 1/7 to 1/4 (LAr gap 2 x 1.15mm to 2 x 3.09mm)

• Required energy resolution achieved – Sampling term ≤ 10%/√Ē, only ≈300 MeV electronics noise despite multilayer electrodes

– Impact of in-time pile-up at <µ> = 1000 of ≈ 1.3GeV pile-up noise

– Efficient in-time pile-up suppression will be crucial (using the tracker)

Precision on Higgs self coupling 𝜆:

δ𝜆/𝜆 ≈7%

Plots A. Zaborowska, C. Helsens, M. Selvaggi

How to Achieve High Granularity?Realize read-out electrodes as multi-layer PCBs (1.2mm thick)• Signal traces (width wt) in dedicated signal layer

connected with vias to the signal pads

• Traces shielded by ground-shields (width ws) forming 25Ω – 50Ω transmission lines

• capacitance between shields and signal pads Cs will add to the detector capacitance Cd

• Ccell = Cs + Cd ≈ 100 – 1000pF

• The higher the granularity the more shields are necessary Ccell increases

11th FCC-ee Workshop — M. Aleksa (CERN)January 9, 2019 36

Serial noise contribution proportional to capacitance Ccell

4 – 40MeV noise per read-out channel assuming ATLAS-like electronics

Hadronic showers: Energy sums over O(500-10000) cells Plots A. Zaborowska, J. Faltova

FCC-ee

11th FCC-ee Workshop — M. Aleksa (CERN)January 9, 2019 37

“IDEA”“CLIC-detector revisited - CLD”• Calorimetry requirements:– Excellent jet energy resolution (~30%/√Ē)– Radiation tolerance and bandwidth requirements

benign compared to LHC– Particle ID

• Calorimetry based on particle flow– Same technologies as for CLIC/ILC under study

• e.g. Si/W ECAL and Scintillator/Iron HCAL

– On top of that fibre-sampling dual-readout calorimetry could be a very interesting option for future leptonic colliders

• Fine transverse granularity• Need longitudinal segmentation to separate e/𝛾 from π±! Idea with fibres of different length

• Excellent hadronic resolution (simulation ~35%/√Ē)

– Noble liquid based calorimetry?• Calo only: Simulation with DNN calib. for

LAr ECAL + TileCal HCAL: ~37%/√Ē• Fine granularity particle flow reco with ID

Could Noble Liquid Calorimetry Work? (1/2)• Dimensions:

– ECAL: 22X0: ~60 cm radial space for FCC-hh type LAr/Pb calorimeter (including 15cm cryostat thickness)

• Could be further reduced to ~45cm by using W instead of Pb

– ECAL+HCAL: 5-7λ: ~1.2 m radial dimension for TileCal (FCC-hh style) – Calorimetry within Δr = 1.65m (W ECAL + TileCal) to Δr = 1.8m (Pb ECAL +

TileCal).– Only slightly bigger than CLD (ΔrCLD = 1.4m)

11th FCC-ee Workshop — M. Aleksa (CERN)January 9, 2019 38

Ccell=1000pF

Ccell=100pF

Ccell=400pF

Ccell=700pF

FCC-hh

Shaping time τ (s)

Shap

ing

tim

e AT

LAS

(50

ns)

• EM resolution: – Sampling term of a ≈ 10%/√Ē quite easily achievable– Resolution at low energies dominated by noise term

b• Noise term b ≈ 300MeV achieved with FCC-hh

calorimeter• Noise term of b ≤ 100 MeV seems possible for low

energy deposits (optimized cluster size, see next slide)

• In addition for large cell capacitances: Could probably gain factor 1.5 when going to slower shaping times τ ≥ 100 ns (FCC-hh τ = 45ns)

– To measure down to 300 MeV need to minimize material in front of the calorimeter ”thin” Al cryostat or carbon fibre cryostat (R&D program at CERN has been launched, see next slides)

FCC-hh

Conclusions and Outlook

• Noble liquid calorimetry has been successfully used for LHC experiments (ATLAS LAr Calorimeter) – Strengths: Stability, pointing resolution, particle ID, radiation hardness

• Noble liquid calorimetry is proposed for the reference detector of FCC-hh– Simulations show that such a calorimeter would fulfil physics requirements for FCC-hh

• Noble liquid calorimetry is also an interesting option for a FCC-ee experiment!– Preliminary considerations: such a calorimeter could be feasible and would fulfil physics

requirements for FCC-ee– Potentially cheaper than other options!– Layout needs to be adapted to an FCC-ee experiment– A LAr calorimeter should be implemented into FCC-ee experiment in FCC SW– Start full-sim studies and optimization!

• Please join us if you are interested in this promising option!

11th FCC-ee Workshop — M. Aleksa (CERN)January 9, 2019 39

• Concept

• Process

• Scope and themes

• Budget

• Implementation

https://ep-dep.web.cern.ch/rd-experimental-technologies(you find some more links there)

Strategic R&D Programme on Technologies for future Experiments

C. Joram, EP FCC-ee week 09 January 2019 55

An initiative of the CERN EP department

Working Groups packages Convenors

WP 1: Silicon detectors Heinz Pernegger, Luciano Musa, Petra Riedler, Dominik Dannheim

WP 2: Gas detectors Christoph Rembser, Eraldo Oliveri

WP 3: Calorimetry and light based detectors Martin Aleksa, Carmelo D'Ambrosio

WP 4: Detector Mechanics++ Corrado Gargiulo, Antti Onnela

WP 5: IC technologies Federico Faccio, Michael Campbell

WP 6: High Speed Links Paolo Moreira, Francois Vasey

WP 7: Software Graeme Stewart, Jakob Blomer

WP 8: Detector Magnets Herman Ten Kate, Benoit Cure

Steering committee

Philippe Farthouat, Roger Forty, Patrick Janot, Christian Joram (coordinator), Manfred Krammer (chair), Lucie Linssen, Pere Mato, Burkhard Schmidt, Werner Riegler

R&D themes

C. Joram, EP FCC-ee week 09 January 2019 56

BudgetWorking groups estimated - for the agreed 5-year workplans - their needs in terms of

• material

• longer term investment (lab, instruments)

• fellows

• Students

These were scrutinized and squeezed by the steering group.

Total budget request: 62.9 MCHF, i.e. 12.6 MCHF p.a. (fellows/students converted to money)

In parallel, CERN management created, from 2020 on, a budget line “RDD - R&D for future detectors” and sources it with ~6 MCHF p.a. with a promise for ~8 MCHF p.a.

Problem: a part of the 8 MCHF is used to pay staff salaries. For the time being, we are lacking a substantial part of the budget.

100 k p.a./ 50 k p.a.

C. Joram, EP FCC-ee week 09 January 2019 57

Thanks !