status of the cbm experiment v. friese gesellschaft für schwerionenforschung darmstadt, germany...

Status of the CBM experiment

V. FrieseGesellschaft für Schwerionenforschung

Darmstadt, [email protected]

for the CBM Collaboration

2 2. Workshop „Challenges and Opportunities“, GSI, October 2003 V. Friese

nuclei

hadronic phase

The goal of high energy heavy-ion physics: Exploring the QCD phase diagram

SPS

RHIC

dilute hadron gas

RHIC, SPS : • crossover QGP hadrons• almost immediate freeze-out

dense bayonic medium

lattice QCD : Fodor / Katz, Nucl. Phys. A 715 (2003) 319

SIS300 : • system experiences a stage of dense baryonic matter• may come near to the end point: critical phenomena ?

SIS300


30 AGeV : Exciting physics

NA49, J. Phys. G 29 (2003), and preliminary

AGS

SPS

RHIC

Au+Au / Pb+Pb

p+p

Sharp structure in K+/+ exc. fct.,constancy of kaon slopes :Signal of 1st order PT ?

That’s where CBM will measure !


Physics questions and observables

Hadron properties in dense matterChiral symmetry restoration,generation of hadron masses

Penetrating probes : e+e- with high precision / statisticsThreshold production of open charm : D hadrons

Deconfinement, phase transition, critical phenomenaStrangeness production, flow, fluctuations

, K , p direct, , via decay topology

J/ e+e-

Nuclear equation of state at highest baryon densities

Exc. fct. of particle production and collective flow


Challenges and opportunities

e+e-, J/ e+e-, , D : extremely rare probes !

Highest beam intensities / interaction rates needed !

Opportunity: Systematic measurement of these probes as function of beam energy and projectile/target size

W. Cassing et al, Nucl. Phys. A 691(2001) 753


Conditions and requirements

High track multiplicity (700-1000)Beam intensity 109 ions/sec.High interaction rate (10 MHz)

Detector tasks:Tracking in high-density environment STS + TRDReconstruction of secondary vertices (resolution 50 m) STSHadron identification : / K / p separation (t 80 ps) TOFLepton identification : / e separation (pion suppression 10-4) TRD + RICH

central Au+Au @ 25 AGeV, UrQMD + GEANT

Need fast and radiation hard detectors


The CBM detector

Setup in GEANT4


Feasibility, Simulations

D Kπ(π)GSI Darmstadt, Czech Acad. Sci., RezTechn. Univ. Prague

,ω, e+e-

Univ. Krakow,JINR-LHE Dubna

J/ψ e+e-

INR Moscow

Hadron ID Heidelberg Univ,Warsaw Univ.Kiev Univ. NIPNE BucharestINR Moscow

GEANT4: GSI

TrackingKIP Univ. HeidelbergUniv. MannheimJINR-LHE Dubna

Design & constructionof detectors

Silicon PixelIReS StrasbourgFrankfurt Univ.,GSI Darmstadt,RBI Zagreb,Krakow Univ. LBNL Berkeley

Silicon StripSINP Moscow State U.CKBM St. PetersburgKRI St. Petersburg

RPC-TOFLIP Coimbra, Univ. S. de Compostela,Univ. Heidelberg,GSI Darmstadt,NIPNE BucharestINR MoscowFZ RossendorfIHEP ProtvinoITEP Moscow

Fast TRDJINR-LHE, DubnaGSI Darmstadt,Univ. MünsterINFN Frascati

Straw tubesJINR-LPP, DubnaFZ RossendorfFZ JülichECAL ITEP Moscow RICH

IHEP Protvino

Trigger, DAQKIP Univ. HeidelbergUniv. MannheimGSI DarmstadtKFKI BudapestSilesia Univ.

MagnetJINR-LHE, DubnaGSI Darmstadt

AnalysisGSI Darmstadt,Heidelberg Univ,

Data Acquis.,Analysis

R&D working packages


Feasibility study : open charm

Key variable to suppress background: secondary vertex position

D0 K-+ (central Au+Au @ 25 AGeV)

c = 124 m, BR = 3.8 %BG suppression 2 x 105

Assuming <D0> = 10-3 :

S/B 1SNR = 3 at 2 x 106 eventsdetection rate 13,000 / h

Similar study for D+ K- + + (c = 315 m, BR = 9 %)

First estimate S/B 3

Crucial detector parameters: Material in tracking stationsSingle hit resolution


Monolithic Active Pixel Sensors (MAPS)

Pitch 20 m

Low material budget : Potentially d = 20 m

Excellent single hit resolution : 3 m

S/N = 20 - 40

R&D (IReS / LEPSI Strasbourg) : radiation hardness, readout speed

MIMOSA IV Fallback solution : hybrid pixel detectorssee talk by P. Riedler


K / separation by time of flight

Separation power depends on: flight path time resolution


Time of flight : K- identifcation for D0

Decay + PID efficiency K- from D0 decay

Key issues for detector design : rate capability time resolution scale


Detector R&D : Resistive Plate Chambers (RPC)

Recent developments at LIP Coimbra : Time resolution ( 90 ps) essentially unchanged up to 25 kHz/cm2

Challenge : Counting rate


FOPI-RPC-R&D

90 cm-14 strips-4 gaps

t < 80 ps

Tail < 2%

Detector resolution

In house developments:90 cm-14 strips anode

2 RPCs in gas box


Feasibility study: J/ e+e-

with cuts: pt(e+,e-) > 1 GeV/c, lab 25o, > 10o

without cuts (incl. misident. pions)

e+e-

e+e-

DDe+e-+X

e+e-

J/e+e-

sumStudy in CDR : S/B 10 after cuts

Now available: conversion in detector materialdominating component, but mostly at low pt

study ongoing


Feasibility study : e+ e-

Background from conversion dominatesAfter cut on e+e- vertex :SNR 3 in 1 M eventsstudy ongoing, tracking needed


Tracking in the STS

TRACK RECONSTRUCTION

XZ (bending) / YZ (non-bending)

TRACK RECONSTRUCTION

XZ (bending) / YZ (non-bending)


Tracking in the STS

RECONSTRUCTION PROGRAMbased on the Cellular Automaton Method

(KIP Heidelberg)

RECONSTRUCTION PROGRAMbased on the Cellular Automaton Method

(KIP Heidelberg)

RECO STATISTICS 100 events Refprim efficiency : 98.36 | 46562Refset efficiency : 94.85 | 49250Allset efficiency : 90.09 | 64860Extra efficiency : 77.79 | 15610Clone probability : 0.11 | 74Ghost probability : 5.18 | 3358Reco MC tracks/event : 648Timing/event : 175 ms

RECO STATISTICS 100 events Refprim efficiency : 98.36 | 46562Refset efficiency : 94.85 | 49250Allset efficiency : 90.09 | 64860Extra efficiency : 77.79 | 15610Clone probability : 0.11 | 74Ghost probability : 5.18 | 3358Reco MC tracks/event : 648Timing/event : 175 ms

RECONSTRUCTIONRECONSTRUCTION•Fetch ROOT MC data•Copy to local arrays and sort•Create segments•Link segments•Create track candidates•Select tracks

Reconstruction efficiency > 95 %


Magnet design

Superconducting dipole magnetField 1 T over 1 m

Field calculatiop by TOSCA


DAQ / Trigger Architecture

clock

Practically unlimited size

Max. latency uncriticalAvr. latency relevant

Detector

Front endADC

Buffer memory

Event builderand selector

Self triggered digitization: Dead time free

Each hit transported asAddress/Timestap/Value

Compensates builder/selector latency

Use time correlation of hits to define events.Select and archive.

Challenge : reconstruct 1.5 x 109 track/sec.data volume in 1st level trigger 50 Gbytes/sec.

see talk by L. Schmitt


EU FP6 HP:

Joint Research Projects (approved):

• Fast gaseous detectors • Advanced TOF Systems• Future DAQ and trigger systems

Network activities (approved):

• CBMnet

INTAS:

Submitted proposals to the INTAS-GSI joint call:

• Silicon Strip Detectors• Electromagnetic calorimeter• Transition Radiation detectors• Straw tube tracker• Resistive Plate Chambers

Proposals to EU FP6 (Design and Construction of new facilities) in preparationCall end of 2003

CBM participation in EU programmes


Croatia: RBI, Zagreb

Cyprus: Nikosia Univ. Czech Republic:Czech Acad. Science, RezTechn. Univ. Prague France: IReS Strasbourg

Germany: Univ. Heidelberg, Phys. Inst.Univ. HD, Kirchhoff Inst. Univ. FrankfurtUniv. Mannheim Univ. MünsterFZ RossendorfFZ JülichGSI Darmstadt

Russia:CKBM, St. PetersburgIHEP ProtvinoINR TroitzkITEP MoscowKRI, St. PetersburgKurchatov Inst., MoscowLHE, JINR DubnaLPP, JINR DubnaSINP, Moscow State Univ.

Spain: Santiago de Compostela Univ. Ukraine: Shevshenko Univ. , Kiev

USA: LBNL Berkeley

Hungaria:KFKI BudapestEötvös Univ. Budapest

Italy: INFN CataniaINFN Frascati

Korea:Korea Univ. SeoulPusan Univ.

Poland:Krakow Univ.Warsaw Univ.Silesia Univ. Katowice Portugal: LIP Coimbra

Romania: NIPNE Bucharest

The CBM R&D Collaboration : 35 institutions

status of the cbm experiment v. friese gesellschaft für schwerionenforschung darmstadt, germany...

Documents

opportunities e e

e separation pion suppression

geant4sqm03 atlantic

319sqm03 atlantic beach30

warsaw univ

d hadronsdeconfinement

high interaction rate

simulationsd kgsi darmstadt