119194439
Correlations and fluctuations studied with ALICE
The measurement of particle correlations and event-by-event fluctuations of physical observables allows to study a large variety of properties of the matter produced in ultra relativistic heavy-ion collisions. We will present results for two-particle correlations, mean transverse momentum fluctuations, and net charge fluctuations in Pb-Pb collisions at = 2.76 TeV.
16249880
Performances of 4-gap timing RPCs for relativistic ions in the range Z=1-6
Results from 4-gap Resistive Plate Chambers (RPCs) under irradiation by fully stripped relativistic ions (normalized momentum p/M = γβ = 2.7, atomic charge Z = 1−6) are presented. A time resolution of 80 ps at high efficiency has been obtained by using standard `off the shelf' 4-gap timing RPCs from the new HADES time-of-flight wall. The resolution worsened to 100 ps for ~ 1 kHz/cm2 proton flux and for ~ 100 Hz/cm2 carbon flux. The chambers were operated at a field E = 100 kV/cm, showing a high stability during the measurements. It seems to exist ample room for improvement, in particular regarding the time resolution.
121398902
Design and Construction of a TPC using GEM Foils for Gas Amplification
We report on the development of a large Time Projection Chamber (TPC) for the e+e- Linear Collider (LC). Our studies concentrate on the use of Gas Electron Multiplier (GEM) foils for the gas amplification in the TPC. Charge transfer measurements are performed using a triple-GEM structure installed into a small test chamber which is irradiated with an 55Fe source. This device is operated in high magnetic fields up to 5 T. No severe drop in primary ionisation statistics is observed, but an improved suppression of ion backdrift is achieved. For optimum settings the relative ion backdrift drops to only 2 per mil. Additionally, the width of the charge cloud created by individual 55Fe photons is measured using a finely segmented strip readout behind the triple GEM structure. Charge widths between 0.2 and 0.5 mm RMS are observed. This charge broadening is reduced in high magnetic fields. Based on these experiments a prototype GEM-TPC has been constructed for further tests in the 5 T magnet and in test beams.
114185756
Operational experience with the D0 silicon tracker
122225376
An investigation of the antinuclei and nuclei production mechanism in Pb + Pb collisions at 158 A GeV
We investigate the production mechanisms of p, d, t, 3He, 4He, 6Li, , and in Pb+Pb collisions at 158 A GeV measured near zero transverse momentum with the NA52 experiment at the CERN SPS. We find evidence that nuclei and antinuclei in Pb+Pb collisions are mainly produced via the coalescence mechanism out of a thermalized source of hadrons, at a time close to the thermal freeze-out of hadrons corresponding to a temperature of ~120 MeV.
124388402
Strangelet search and particle production studies in Pb + Pb collisions at 158-A-GeV/c at CERN SPS
We searched for long-lived strange quark matter particles, so-calledstrangelets, and studied particle and antiparticle production in Pb+Pb collisions at 158 GeV/c per nucleon at zero degree production angle. We give upper limits for the production of strangelets covering a mass to charge ratio up to 120 GeV/c 2 and lifetimest lab>1.2 μs and plot invariant differential production cross sections as a function of rapidity for a variety of particles.
119238918
A beam monitor detector based on doped silica and optical fibres
A beam monitor detector prototype based on doped silica fibres coupled to optical fibres has been designed, constructed and tested, mainly for accelerators used in medical applications. Scintillation light produced by Ce and Sb doped silica fibres moving across the beam has been measured, giving information on beam position, shape and intensity. Mostly based on commercial components, the detector is easy to install, to operate and no electronic components are located near the beam. Tests have been performed with a 2 MeV proton pulsed beam at an average current of 0.8 μA. The response characteristics of Sb doped silica fibres have been studied for the first time.