T.Peitzmann Status of the ALICE Project NIKHEF annual scientific meeting Thomas Peitzmann Universiteit Utrecht
Jan 14, 2016
T.Peitzmann
Status of the ALICE Project
NIKHEF annual scientific meeting
Thomas PeitzmannUniversiteit Utrecht
T.Peitzmann
The Quark-Gluon-Plasma
QCD ground state– color charge of quarks and gluons
is confined
– chiral symmetry spontaneously broken
pressure or heat leads to overlap of hadrons– intuitive in bag model
new state of matter:– color charges can move between
hadrons
– deconfinement: quark-gluon-plasma
– restoration of chiral symmetry
T.Peitzmann
The QCD Phase Diagram
SPS– QGP probably reached
– dominated by transition and hadron gas
– theoretically extremely difficult
RHIC and LHC– dominated by QGP
– theoretically simpler» coupling s small
» thermodynamical “limit”
» baryon. chem. potential b = 0
– new physical observables» heavy quarks» jets
T.Peitzmann
People (NIKHEF and Utrecht University)
PhD– M. van Leeuwen NA49
» strangeness and charm yields
– E. van der Pijll WA98» direct photons
– P. de Rijke NA57» omega production
– E. Schillings NA57» lambda polarisation
– A. Sokolov ALICE» SSD module tests
staff– M. Botje
– N. van Eijndhoven
– R. Kamermans
– P. Kuijer
– G.-J. Nooren
– T. Peitzmann
– R. Snellings
T.Peitzmann
SPS: Reaping The Harvest
Example 1: WA98 (E. van der Pijll)– study of direct photon production
» signal of hot initial state in heavy ion collisions
» very difficult: small signal with high background
– direct photon signal observed in WA98
– development of new analysis method
– extension of analysis to lower transverse momenta
» even more difficult!
Example 2: NA57 (E. Schillings, P. de Rijke)– polarisation (E. Schillings, see
talk)» small polarisation at mid-rapidity
– production (P. de Rijke)» understanding the systematic
errors alignment, efficiencies, …
T.Peitzmann
transverse mass spectra of different hadron species
well described by thermalized source
measures freeze-out conditions– hadronic interactions stop
– similar temperatures for all SPS energies
– high average expansion velocity
Hydrodynamical Model Fits To NA49 Data
M. van Leeuwen
T.Peitzmann
RHIC: Joining The -Party
exciting data from first beam times at RHIC
the most important physics activity in present day heavy ion physics is happening at RHIC
STAR one of the major players– substantial contribution
to be built up! see talk by R. Snellings
central Au+Au collision at sNN=200GeV in the STAR TPC
STARSTAR
T.Peitzmann
LHC: Preparations for ALICE
hardware contribution: silicon strip detector– design and prototyping well under
way physics simulation
– efforts being started
T.Peitzmann
Hardware Contributions
•DetectorDetector
•FE moduleFE module
•EndcapEndcap
•FEROMFEROM
•DAQDAQAlice Inner
Tracking System
ADC racks
outside magnet
5mm
50 cm
25 m
200 m
•CF supportCF support
•CoolingCooling
T.Peitzmann
Status Of Technical Work
preseries of double sided strip detectors – delivered (Canberra, SINTEF,
ITC)– tested (IRES, Trieste)
ladder spaceframes– delivered (St. Petersburg)
ASICs for endcap– design ready (NIKHEF/UU)
readout chain using prototype ASICs– first test (NIKHEF/UU)
testequipment for ASICs and hybrids– operational (NIKHEF/UU)
ladder assembly robot– near to completion (NIKHEF/UU)
first silicon strip detector module– NIKHEF/UU + IRES design
– manufactured at IRES by Ukraine people
– to be tested at NIKHEF/UU
T.Peitzmann
Tests Of SSD With Infrared Laser
laser wavelength chosen to optimize penetration depth– close to band gap energy
– 20-30% light absorbed
– nearly uniform density of ionization
properties adequate for detector tests– beam spot ≈ 30 µm
» larger than for particle, but small compared to strip pitch
– precision of positioning ≈ 1.5 µm
A. Sokolov
T.Peitzmann
2-Dimensional Map Of Collected Charge
strip structure visible– aspect ratio distorted
» y-axis compressed by factor 15
» true angle: 35 mrad
setup used for– dead strip search
– relative calibration
– measurement of charge sharing
T.Peitzmann
Charge Sharing Around Dead Strip
T.Peitzmann
ALICE Physics Studies (Simulation) work on the Physics Performance
Report for ALICE pA physics
– important link pp - pA - AA
– nuclear modifications
– no thermalization/phase transition
further simulation studies foreseen– prepare analysis framework for
future data taking (pp, pA and AA) full tracking with ITS and TPC
example: impact parameter vs. charged multiplicity– HIJING simulations
T.Peitzmann
Summary
physics analysis from SPS experiments– very fruitful!
participation in STAR– major activity in heavy ion group
gearing up for ALICE– hardware contribution well under
way
– increase effort on physics simulations