towards a clic detector, opportunities for r&d

1Lucie Linssen, Tel Aviv, 21/5/2009

Towards a CLIC detector, opportunities for R&D

Lucie Linssen

CERN

Outline and useful links

Outline: • Short introduction to the CLIC accelerator project• CLIC physics• CLIC detector issues

– difference wit ILC case– Recent simulation results

• R&D opportunities

• Outlook

Useful links:• CERN user web page• http://user.web.cern.ch/user/Welcome.asp

• Linear Collider Detector project at CERN• http://lcd.web.cern.ch/LCD/NewWelcome.html

• CLIC08 workshop, October 14-17 2008 (next one: October 12-16 2009)• http://project-clic08-workshop.web.cern.ch/project-clic08-workshop/


http://user.web.cern.ch/user/Welcome.asp


CLIC: Compact LInear Collider

No individual RF power sources

Two Beam Scheme:

Drive Beam supplies RF power

• 12 GHz bunch structure

• low energy (2.4 GeV - 240 MeV)

• high current (100A)

Main beam for physics

• high energy (9 GeV – 1.5 TeV)

• current 1.2 A

CLIC two-beam module


Drive Beam

Main Beam

2 m

20760 modules

to be constructed

e+ injector, 2.4 GeV

e- injector2.4 GeV

CLIC overall layout

3 TeV

e+ main linace- main linac , 12 GHz, 100 MV/m, 21.04 km

BC2BC2

BC1

e+ DR365m

e- DR365m

booster linac, 9 GeV, 2 GHz

decelerator, 24 sectors of 868 m

IP1

BDS2.75 km

BDS

2.75 km

48.3 km

drive beam accelerator2.37 GeV, 1.0 GHz

combiner rings Circumferences delay loop 80.3 m

CR1 160.6 mCR2 481.8 m

CR1CR2

delayloop

326 klystrons33 MW, 139 s

1 km

CR2delayloop

drive beam accelerator2.37 GeV, 1.0 GHz

326 klystrons33 MW, 139 s

1 km

CR1

TAR=120m

TAR=120m

245m 245m

Drive Beam

Generation Complex

Main Beam

Generation Complex

Main & Drive Beam generation

complexes not to scale 5Lucie Linssen, Tel Aviv, 21/5/2009


Main beam accelerating structures

Technologies:

Brazed disks - milled quadrants

Objective:

• Withstand of 100 MV/m without

damage

• Breakdown rate < 10-7

• Strong damping of HOMs

Collaboration: CERN, KEK, SLAC


Best result so far

High Power test of

T18_VG2.4_disk

(without damping)• Designed at CERN,

• Machined by KEK,

• Brazed and tested at

SLAC

Design: 100 MV/M loaded

BR: 10-7

CLIC

target

Improvement by

RF conditionning

CLIC test facility CTF3


2005

2004

CLEX

CR

TL1

DL

TL2

Beam up to

dump

(August 08)

Demonstrate Drive Beam generation (fully loaded acceleration, beam intensity and bunch frequency multiplication x8)

Demonstrate RF Power Production and test Power Structures

Demonstrate Two Beam Acceleration and test Accelerating Structures

Operational Experience (reliability) by continuous operation (10m/year)

Demonstrate Drive Beam generation (fully loaded acceleration, beam intensity and bunch frequency multiplication x8)

Demonstrate RF Power Production and test Power Structures

Demonstrate Two Beam Acceleration and test Accelerating Structures

Operational Experience (reliability) by continuous operation (10m/year)

Cleaning ChicaneFirst moduleINJECTOR


Tentative long-term CLIC scenario

First

Beam?

Technical

Design

Report (TDR)

Conceptual

Design

Report (CDR)

Project

approval ?

2007 2008 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023

R&D on Feasibility Issues

Conceptual Design

R&D on Performance and Cost issues

Technical design

Engineering Optimisation&Industrialisation

Construction (in stages)Construction Detector

2009

Technology evaluation and Physics assessment based on LHC results

for a possible decision on Linear Collider with staged construction starting

with the lowest energy required by Physics

CLIC parameters


LCD@CERN


Linear Collider Detector project at CERN

What is our goal ?

We are working towards a linear collider detector which will operate

in an energy range (CM) from 500 GeV to 3 TeV

Working together with the ILC concepts (SiD, ILD, 4th) and with the detector

collaborations (LC-TPC, EUDET, FCAL, CALICE).

In a concerted effort with the individual concepts, we work towards

describing the possible changes or upgrades to the ILC concepts

to make them compatible with multi-TeV energies and CLIC beam conditions.

CLIC physics


General Physics Context

• New physics expected in TeV energy range– Higgs, Supersymmetry, extra dimensions, …?

• LHC will indicate what physics, and at which energy scale ( is 500 GeV enough or need for multi TeV? )

• Even if multi-TeV is final goal, most likely CLIC would run over a range of energies (e.g. 0.5 – 3.0 TeV)

• ILC detector concepts are excellent starting point for high energy detector

http://documents.cern.ch/cgi-bin/setlink?base=cernrep&categ=Yellow_Report&id=2004-005

• Like for ILC, assume 2 CLIC detectors in pull push mode


http://documents.cern.ch/cgi-bin/setlink?base=cernrep&categ=Yellow_Report&id=2004-005

Cross-sections at a few TeV


CLIC at 3 TeV: assume 200 fb-1 per year

1/s log(s)

Lucie Linssen, Tel Aviv, 21/5/2009

If there is a light SM-like Higgs…

The cross-section at ~3TeV is large

access to very rare decays (BR~10-4).

Measure Higgs couplings to leptons, for

instance with 0.5 ab-1, we expect ~70 H+-

decays for Mh=120 GeV/c2, and measure the

couplings with ~4% precision.

15

Teubert, etc


Pysics case: Higgs

If there is only a light SM-like Higgs, it will be found at hadron colliders,

and most of their properties (spin, couplings,…) can be determined

with very good precision at a low energy linear collider. However, to

complete the measurements of its properties (eg, lepton couplings) and

more important, to measure with precision the Higgs potential (hence

non-trivial test of the SSB mechanism), a multi-TeV linear collider is

crucial.

If there is a light Higgs CLIC could search indirectly for accompanying new physics up to 100 TeV and identify any heavier partners

16

Ellis, Teubert, etc


Supersymmetry: LHC vs LC

17

LHC is good with sparticles that mainly interact strongly, (gluino, squarks, …), while

a LC could complement the spectra with sparticles that mainly interact weakly

(sleptons,

neutralinos,…)

Teubert, etc

Physics case: Supersymmetry

68%

90%

95%


Physics case: Extra dimensions

Extra-dimension scenario (Randall, Sundrum) predicts production of

• TeV-scale graviton resonances, decaying into two fermions.

• Cross sections are large, but wide range of parameters.


By counting the number of events

with missing energy and photons, at

different centre-of-mass energies we

can measure the number of extra

dimensions and the Planck scale.

Not possible at LHC, easy at a LC with

enough energy!

Ellis, Teubert, etc

Luminosity spectrum and effect onResonance Production

@CLIC significant beamstrahlung

→ Luminosity spectrum not as

sharply peaked as at lower energy

→ need for luminosity

Z’

+ ISR

+ beamstrahlung



CLIC detector issues,

and comparison with ILC


ILC experiment concepts

SiDILD

4th


Harry Weerts

CLIC detector issues


3 main differences with ILC:

•Energy 500 GeV => 3 TeV

•More severe background conditions

•Due to higher energy

•Due to smaller beam sizes

•Time structure of the accelerator

CLIC time structure


Train repetition rate 50 Hz

CLIC

CLIC: 1 train = 312 bunches 0.5 ns apart 50 Hz

ILC: 1 train = 2820 bunches 308 ns apart 5 Hz

Consequences for CLIC detector:

•Assess need for detection layers with time-stamping

•Innermost tracker layer with ~ns resolution

•Additional time-stamping layers for photons and for neutrons (needed?)

•Or …. all-detector time stamping at the 10 ns level

•Readout/DAQ electronics will be different from ILC

•Power pulsing has to work at 50 Hz instead of 5 Hz

Beam-induced background

Background sources: CLIC and ILC similar

Due to the higher beam energy and small bunch

sizes they are significantly more severe at CLIC.

Main backgrounds:

• CLIC 3TeV beamstrahlung ΔE/E = 29% (10×ILCvalue)

– Coherent pairs (3.8×108 per bunch crossing) <= disappear in beam pipe– Incoherent pairs (3.0×105 per bunch crossing) <= suppressed by strong solenoid-field– γγ interactions => hadrons (2.7 hadron events per bunch crossing)

• Muon background from upstream linac

– More difficult to stop due to higher CLIC energy (active muon shield)


CLIC centre-of-mass energy spectrum


Due to beamstrahlung:

• At 3 TeV only 1/3 of the luminosity is in the top 1% Centre-of-mass energy bin

• Many events with large forward or backward boost

Beamstrahlung, continued…..


At 3 TeV many events have

a large forward or backward

boost, plus many back-

scattered photons/neutrons

3 TeV

3 TeV

Extrapolation ILC = > CLIC


Adrian Vogel, DESY

For full LDC detector simulation at 3 TeV

Simulation of e+e- pairs from beamstrahlung

•Conclusion of the comparison:•ILC, use 100 BX (1/20 bunch train)

•CLIC, use full bunch train (312 BX)

•CLIC VTX: O(10) times more background

•CLIC TPC: O(30) times more background

LDC 3 TeV, with forward mask

<= 10% beam crossing in ILD detector at 500 GeV


Vertex DetectorVertex detector hits from incoherent pairs, B=5T,

two angular coverages

for

312 BX

PR

ELI

MIN

AR

Y

“barrel”

Vertex Detector

Daniel Schulte

vertex opening angle


Forward region detectors

e.g. LUMICAL, measuring luminosity

Using BhaBha scattering

Iftach Sadeh, Tel Aviv univ.

Full simulation of LUMICAL at

3 TeV, adaptation of detector

geometry and opening angle.

Simulation of back-scattering

from the front-face of

LUMICAL

CLIC Tracking

Vetex and Tracking issues:• Due to beam-induced background and short time between bunches:

– Inner radius of Vertex Detector has to become larger (~25 mm)– High occupancy in the inner regions

• Narrow jets at high energy– 2-track separation is an issue for the tracker/vertex detector– Track length may have to increase (fan-out of jet constituents)?

32Lucie Linssen, Tel Aviv, 21/5/2009 3TeV e+e- W+W- qqqq

CLIC Calorimetry

33Lucie Linssen, Tel Aviv, 21/5/2009 33

•Higher energy => need deeper HCAL (≥8λi)

•Cannot increase coil radius too much => need heavy absorberChoice of suitable HCAL material

•Choice of Calorimeter technology (PFA or Dual readout)

3 TeV e+e- event on

SiD detector layout,

illustrating the need

for deeper

calorimetry

Jet multiplicities


3TeV e+e- W+W- qqqq

Longitudinal shower containment


Peter Speckmayer / Christian Grefe

Lucie Linssen, Tel Aviv, 21/5/2009 37

Tungsten – Scintillator calorimeter Conventional Calorimetry, resolution for 8λ

Hadron Calorimetry


Lucie Linssen, Tel Aviv, 21/5/2009 38

230-270 GeV 6,7,8,9 -> 40 λ

Hadron Calorimetry


Which calorimetry at CLIC energies?


To overcome known shortfalls from LEP/LHC experience, new

concepts/technologies are chosen for ILC:

•Based on Particle Flow Algorithm

•Highly segmented (13-25 mm2) ECAL (analog)

•Very highly segmented ECAL (digital)

•Highly segmented (1 cm2) HCAL (digital)

•Segmented HCAL (analog)

•Based on Dual (Triple) readout

•Sampling calorimeter

•Plastic fibres

•Crystal fibres (<= materials studies)

•Fully active calorimeter (EM part)

•Crystal-based

Method and Engineering

difficult, but conventional


difficult, but conventional


difficult and non-proven


difficult and non-proven

Limited in energy-range

to a few hundred GeV

Limited in energy-range

to a few hundred GeV

Not limited in energy

range

Not limited in energy

range

Opportunities for Detector R&D and engineering studies


Opportunities for detector R&D

Most of the detector R&D currently carried out for the ILC is most relevant for CLIC.

In several aspects the CLIC R&D is already being integrated into the present technology collaborations CALICE, LC-TPC, FCAL)

R&D needed beyond present ILC developments:• Time stamping• Alternative to PFA calorimetry (dual readout?)• Mechanical engineering studies

– Heavy calorimeter concept

– Large high-field solenoid concept

– Integration studies

• Precise stability/alignment studies• Power pulsing and other electronics developments


Precise alignment/stability

• Precise alignment studies/technologies– Beam focusing stability !!– How to link left-arm and right-arm?

• Lumical =>measurement using Bhabha scattering• Alignment of last quadrupoles at +- 3.5 m

– ILC alignment requirements => <4 μm (x,y), <100 μm (z)– CLIC requirement is be more severe

43Lucie Linssen, Tel Aviv, 21/5/2009 Leszek Zawiejski, FCAL collab.Daniel Schulte CLIC08.

Mechanical engineering studies

– Heavy calorimeter concept (with ≥ λi)• Tungsten could be suitable from the physics point of view• Difficult to produce, normally not in large plates, very expensive• Brittle => overall concept design

– Large high-field solenoid concept• Extrapolation from CMS solenoid• Replacement of Al coil stabiliser by stronger doped alloy (hardware R&D)• Welding technique of reinforced conductor cable (hardware R&D)• Suspension of heavy barrel calorimeter from coil cryostat

– Integration studies• Detailed forward region integration and stabilisation• Overall care for precise mechanical stability (decoupling from accelerator!)• Overall detector integration studies


Conclusions

• Linear Collider Detector project, is now an official project at CERN.

• Currently assessing the adaptations of the ILC concepts to the CLIC environment

– Basic concepts will be similar

– ILC hardware developments are most relevant for CLIC

– Using the same software tools

• A number of areas have been identified, where the CLIC detector at 3 TeV differs from the ILC concepts at 500 GeV

– The initial CLIC concept simulation studies will concentrate on these areas– CLIC-specific R&D will be required in a number of technology domains

• Many thanks to ILC physics community, who helped to get the CLIC detector studies restarted

Welcome to join !!!


SPARE SLIDES


Alternative to PFA calorimetry

R&D on dual/triple readout calorimetry


Basic principle:

•Measure EM shower component separately

•Measure HAD shower component separately

•Measure Slow Neutron component separately

Dual Triple

EM-part=> electrons => highly

relativistic => Cerenkov light

emission

EM-part=> electrons => highly

relativistic => Cerenkov light

emission

HAD-part=> “less” relativistic

=> Scintillation signal

HAD-part=> “less” relativistic

=> Scintillation signal

Slow neutrons => late fraction

of the Scintillation signal

Slow neutrons => late fraction

of the Scintillation signal

Requires broader collaboration on materials + concept

48

SiD Forward Region

LumiCal

20 layers of 2.5 mm W +

10 layers of 5.0 mm W

BeamCal

50 layers of 2.5 mm W

3cm-thick Tungsten Mask13cm-thick BoratedPoly

Centered on the outgoing beam line

EC

AL

Beampipe

+/- 94 mrad (detector)

+101 mrad, -87mrad (ext. line)


towards a clic detector, opportunities for r&d

Documents

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clic beam conditions

amain beam

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drive beam supplies

clic scenariofirstbeam

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