Johann M. Heuser GSI Helmholtz Center for Heavy Ion Research GmbH, Darmstadt, Germany 3 rd International Conference on New Frontiers in Physics, Kolymbari,

Johann M. Heuser

GSI Helmholtz Center for Heavy Ion Research GmbH, Darmstadt, Germany

3rd International Conference on New Frontiers in Physics , Kolymbari, Crete, Greece, July 2014

Status of the CBM experiment

J. Heuser - Status of the CBM experiment at FAIR 2

Outline

• Compressed Baryonic Matter • Meeting the experimental challenges• The CBM experiment • Development of CBM components• Examples of performance studies• Time-line

ICNFP2014


The CBM Physics Program

• comprehensive program to explore the phase diagram of strongly interacting matter at highest net baryon densities and moderate temperatures:

“Compressed Baryonic Matter”

• using heavy-ion collisions from 2 – 45 GeV/nucleon (sNN = 1.9 – 9 GeV) and proton-nucleus collisions at FAIR

• observables: excitation functions of yields and phase space distributions ofstrangeness, di-leptons, charm, strange matter

• few or no data at FAIR energies yet

ICNFP2014

Courtesy of K. Fukushima & T. Hatsuda


Experimental challenges: Rare probes

ICNFP2014

min. bias Au+Au collisions at 25 AGeV (from HSD and thermal model)

SPS Pb+Pb 30 A GeVSTAR Au+Au sNN=7.7 GeV

motivating CBM experimental requirements in precision and rates

particle multiplicity branching ratio


CBM Detector – Design constraints

High interaction rates• 105 – 107 Au+Au collisions/sec.

Fast and radiation hard detectors

Free streaming read-out • time-stamped detector data• high speed data acquisition

On-line event reconstruction • powerful computing farm • 4-dimensional tracking • software triggers

ICNFP2014

Central Au+Au collision at 25AGeVUrQMD + GEANT + CbmRoot

tracks in the Silicon Tracking System


CBM experiment set-up

ICNFP2014

• CBM (FAIR MSV Module 1)• Cave fully designed


CBM experiment set-up

ICNFP2014

HADES

SiliconTrackingSystem

Micro VertexDetector

Dipolemagnet

Ring ImagingCherenkovDetector

Transition Radiation Detector

Resistive Plate Chambers (TOF)

Electro-magneticCalorimeter(parking position)

Projectile SpectatorDetector

Muon Detection System(parking position)

beam dump

beam

Target


Super-conducting dipole magnet

ICNFP2014

• aperture: 140 cm vertical, 280 cm horizontal

• weight 140 tons• field integral 1 Tm• self protecting coil: Cu/SC = 9


Silicon Tracking in CBM

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p+C, 30 GeV

few charged particles

• STS task: track identification + momentum determination - from few charged particles in p+A collisions at SIS100- to hundreds of charged tracks in A+A collisions at SIS100 and SIS300 - at 105 to 107/s collisions per second

• identification of decay topologies within its aperture • links to further detectors: MVD (upstream) and MUCH/RICH (downstream)

central Au+Au, 8 AGeV

~350 charged particles

central Au+Au, 25 AGeV

~700 charged particles

UrQMD + GEANT + CbmRoot


System concept

ICNFP2014

Aim: a large-aperture, highly granular, low-mass detector capable of high data rates

• 8 tracking stations in dipole magnet: between 0.3 m and 1 m from target.

• Aperture: 2.5° < < 25° (38°).• Double-sided micro-strip sensors arranged

in modules on low-mass carbon-fiber supported ladders.

• Readout electronics at periphery• Target chamber/MVD/beam pipe.• Thermal enclosure, sensors at -5 ◦C.

STS

2.5°

25°

beam

target


STS integration concept

ICNFP2014

• 8 stations, volume 2 m3, area 4 m2

• 896 detector modules- 1220 double-sided microstrip sensors- ~ 1.8 million read-out channels- ~ 16 000 r/o STS-XYTER ASICs- ~ 58 000 ultra-thin r/o cables

• 106 detector ladders with 4-5 modules• power dissipation: 42 kW (CO2 cooling)

building block: 4-5 modules per ladder

front-end board: 8 self-triggering

r/o ASICs

sensor

8 tracking stationsladdermech. unit

material budget in physics aperture

[%X0]

ultra-thin r/o cables

1 m


Development of detector components

ICNFP2014

Silicon microstrip sensors

Module assembly

• 300 µm thick, n-type silicon• double-sided segmentation• 1024 strips of 58 µm pitch• strip length 6.2/4.2/2.2 cm• angle front/back: 7.5 deg• rad. tol. up to 1014 neq/cm2

Micro cables Front-end electronics

STS-XYTER ASIC Front-end board

64 Al lines 116 µm pitch, 10 µm thick 14 µm polyimide, up to 55 cm long

J. Heuser - Status of the CBM experiment at FAIR 13ICNFP2014

ROB

FEB

STS Engineering: stations/cabling/cooling

FEB stack 200 Wbi-phase CO2 cooling system

STS electronics total: 42 kW


Micro Vertex Detector

ICNFP2014

Monolithic Active Pixel Sensors (MAPS)

Pixel size: ~ 20 × 20 μm2

Position resolution: σ = 4 μm

⇒ Vertex res.: 50-100 μm (beam axis)

Radiation hardness: 1013 neq/cm2 (non-ion.), 3Mrad (ion.)Readout time: few 10 μs/frame

System integration• 2-4 stations (5, 10, 15,20 cm)• operation in vacuum • thickness per station: <0.5% X0

current prototypeMIMOSA-26:600 k Pixels104 frames/s50 μm thick


RICH Detector

ICNFP2014

Electron identificationRadiator box filled with CO2

2 mirror arrays

photon detectors:MAPMTs (H8500,H10966, R11265)MCP-PMTs (XP85012)

e-π-Separation

MAPMT test array

full-size prototype test at CERN PS


TRD Detector

ICNFP2014

Electron identificationπ-suppression by factor 100 (10) at SIS300 (SIS100)

Achievable with different radiator typesDifferent readout chamber types tested with and w/o (fast) drift region

SIS100:4 layers

SIS300:10 layers

Test beam at CERN-PS

TRD read-out chainSPADIC 1.0 readout chip

Extraction of different signal features in readout chain


MUCH Detector

ICNFP2014

MUCHMUon CHamber systemMuon identification and tracking

• hadron absorbers • tracking stations

GEM

PSD

Straw tubes

Full set-up for SIS-300: 60 cm C+Pb + (20+20+30+100) cm Fe4 GEM stations + 2 straw tube stations (+ TOF)

Reduced set-up for SIS-100:60 cm C+Pb + (20+20+20) cm Fe3 GEM stations

GEM test COSY 2013

+ TOF


TOF Detector

ICNFP2014

Test beams atGSI, ELBE/HZDR,CERN-PS,COSY

Particle identificationTime resolution ≈ 60ps

Resistive Plate Chambers (RPC)TOF wall: active area ~ 120 m2

Setupdistance to target: 10m (SIS300), 6 m (SIS100)

Hit rates:10 – 25 kHz/cm2 (2 – 10 kHz/cm2) for inner (outer) section

10 GeV


Calorimeter Detectors

ICNFP2014

PSDParticipant Spectator Detector

determination of collision centrality and orientation of an event plane

ECALElectro-magnetic CALorimeter

detection of photons and neutral mesons (π0, η) decaying into photons

• “shashlik” type calorimeter • modules of 140 layers of 1 mm lead

and 1 mm scintillator • cell sizes 3 by 3 cm, 6 by 6 cm and 12

by 12 cm. • modules arranged in wall or in a

tower geometry with variable distances from the target.

• full compensating modular lead-scintillator calorimeter with high and uniform energy resolution.

• 44 individual modules, with 60 lead/scintillator layers, surface of 20×20 cm2.

• Read-out via wavelength shifting fibers by MAPDs


DAQ and on-line event selection

ICNFP2014

Free streaming DAQ Time stamped message streams (no trigger!)

Total input data rate: 1 TByte/s; ~1000 input nodes

FLES: High-throughput event building and data analysis by application of massive parallelization to recons-truction algorithms and tasks.

Data reduction by up to a factor of 1000 before storage.

“GreenIT cube”FAIR Tier-0 data center (planned)

6 MW cooling, expandable to 16 MW

FLES prototypes:

LOEWE CIC, Frankfurt

Mini Cube, GSI


Steps of event reconstruction

ICNFP2014

1. Time-slice sorting of detector hits: First step in “pre-event” definition.

2. Track finding – Cellular Automaton: Which hits in the detector layers belong to the same track? - large combinatorial problem- well to be parallelized - applicable to many-core CPU/GPU systems

3. Track fitting – Kalman Filter: Optimization of the track parameters. - recursive least squares method, fast

4. Event determination Which tracks belong to same interaction?

5. Particle finding: Identify decay topologies and other signatures.

1 2 3 4

t

hits


Performance of hyperon measurement

ICNFP2014

5·106 central Au+Au collisions, 25 AGeV

5·106 central Au+Au collisions, 10 AGeV


Di-lepton invariant mass spectra

ICNFP2014

e+e-

μ+μ-

ωφ J/ψ

J/ψφω

central Au+Au collisions at 25 A GeV


Open charm measurement

ICNFP2014

D0 Kπππ D Kππ

D0 Kπππ D KππD0 Kπ

p+C collisions, 30 GeV (SIS100)

Au+Au collisions, 25 AGeV (SIS300)

1012 centr.


Technical Design Reports

ICNFP2014

# Project TDR Status

1 Magnet approved

2 STS approved

3 RICH approved

4 TOF evaluation

5 MuCh evaluation

6 PSD evaluation

7 MVD submission 2014

8 DAQ/FLES submission 2014

9 TRD submission 2014


Time-line

ICNFP2014

2013 2014 2015 2016 2016 2017 2018 2019 2020 2021 2022 2023 2024

construction

Installation

commissioning

expts. at SIS100 ?

expts. at SIS300

cave ready

SIS100 ready

CBM (FAIR MSV Module 1)

series productionprototypes


CBM as experimental facility

ICNFP2014

• electron-hadron configuration• muon configuration • operation right after FAIR start-up, at SIS-100, at SIS-300 energies

example: three possible muon configurations:

“day-1” SIS-100 SIS-300


The CBM Collaboration

ICNFP2014

12 countries, 56 institutions, 516 membershttp://www.fair-center.eu/for-users/experiments/cbm.html

Croatia: Split Univ.China:CCNU WuhanTsinghua Univ. USTC Hefei

Czech Republic:CAS, RezTechn. Univ.Prague

France: IPHC Strasbourg

Hungary:KFKI BudapestBudapest Univ.

Germany: Darmstadt TUFAIRFrankfurt Univ. IKFFrankfurt Univ. FIAS GSI Darmstadt Giessen Univ.Heidelberg Univ. P.I.Heidelberg Univ. ZITIHZ Dresden-RossendorfMünster Univ. Tübingen Univ. Wuppertal Univ.

India:Aligarh Muslim Univ.Bose Inst. KolkataB.H. Univ. VaranasiGauhati Univ.IOP BhubaneswarIIT IndoreIIT KharagpurPanjab Univ. Rajasthan Univ.Univ. of Jammu Univ. of KashmirUniv. of CalcuttaVECC Kolkata

Russia:IHEP ProtvinoINR TroitzkITEP MoscowKRI, St. PetersburgKurchatov Inst., MoscowLHEP, JINR DubnaLIT, JINR DubnaMEPHI MoscowObninsk State Univ.PNPI GatchinaSINP MSU, Moscow St. Petersburg P. Univ.

Ukraine: T. Shevchenko Univ. KievKiev Inst. Nucl. Research

Korea:Pusan Nat. Univ.

Romania: NIPNE BucharestUniv. Bucharest

Poland:AGH Krakow Jag. Univ. KrakowSilesia Univ. KatowiceWarsaw Univ.Warsaw TU

23rd CBM Collaboration Meeting, GSI, April 2014


Back-up slides


Detector acceptance

ICNFP2014

Au+Au 25 AGeV

Au+Au 6 AGeV ybeam = 1.28

ybeam = 1.98


Track reconstruction performance in STS

ICNFP2014

track reconstruction efficiency momentum resolution

• realistic detector geometry, material budget and response functions• cellular automaton and kalman filter algorithms


In-beam test of a prototype STSlow-mass STS module • silicon microstrip sensors

- double-sided, 300 µm thick- 1024 strips of 58 µm pitch - front/back side strips, 7.5 deg angle- radiation tolerant up to 1014 n/cm2

• micro r/o cables (partial read-out)• self-triggering electronics

proton beam, COSY, Jülich

Results• signal amplitudes • cluster sizes • spatial resolution


CBM online data flow

First-level Event Selector

copper ca. 0.5 m

optical some 10 m

optical 100s m


STS-XYTER ASIC

ICNFP2014

STS-XYTER ASIC

• purely data driven read-out• time-stamped data elements

channels 128, polarity +/-

noise 900 e- at 30 pF load

ADC range 16 fC, 5 bit

clock 250 MHz

power < 10 mW/channel

timestamp < 5 ns resolution

out interface 4(5) × 500 Mbit/s LVDS

v1.0 produced(v2.0 under design) UMC 180 nm CMOS

every channel is divided into two sub-channels:

• fast branch: time-stamp• slow branch: signal digitization

noise minimization in self-triggering system:

effective two-level discrimination

• trigger to the timestamp latch is vetoed if ADC-LSB generated no signal

• no transmission of data then

CBM-NET

(v1.0 )

GBT(V2.0)

LSB veto

ts = 30 ns

ts = 80 ns

r/ologic


STS Read-out electronics

ICNFP2014

STS-XYTER ASIC

GBTx chip-set (CERN):3 GBTx, 1 VTRx, 1 VTTx, 1 SCA

42 E-links à 320 Mb/s 3 GBT optical uplinks à 4.48 Gb/s

Front-end Board Read-Out Board

Data Processing Boardtime-slicing

FLES farmonline event computing

• purely data driven read-out• time-stamped data elements

8 STS-XYTER chips1/2/5 LVDS links out

separate power boards

channels 128, polarity +/-

noise 900 e- at 30 pF load

ADC range 16 fC, 5 bit

clock 250 MHz

power < 10 mW/channel

timestamp < 5 ns resolution

out interface 4(5) × 500 Mbit/s LVDS

v1.0 produced(v2.0 under design) UMC 180 nm CMOS

data combiningtime-stamped data

Documents

Johann M. Heuser GSI Helmholtz Center for Heavy Ion Research GmbH, Darmstadt, Germany 3 rd International Conference on New Frontiers in Physics, Kolymbari,