arXiv subjects

J. J. Gaardhoje

Publications and source records attributed to J. J. Gaardhoje.

3 recordsLinked to original sources

arXiv2010

The ALICE TPC, a large 3-dimensional tracking device with fast readout for ultra-high multiplicity events

The design, construction, and commissioning of the ALICE Time-Projection Chamber (TPC) is described. It is the main device for pattern recognition, tracking, and identification of charged particles in the ALICE experiment at the CERN LHC. The TPC is cylindrical in shape with a volume close to 90 m^3 and is operated in a 0.5 T solenoidal magnetic field parallel to its axis. In this paper we describe in detail the design considerations for this detector for operation in the extreme multiplicity environment of central Pb--Pb collisions at LHC energy. The implementation of the resulting requirements into hardware (field cage, read-out chambers, electronics), infrastructure (gas and cooling system, laser-calibration system), and software led to many technical innovations which are described along with a presentation of all the major components of the detector, as currently realized. We also report on the performance achieved after completion of the first round of stand-alone calibration runs and demonstrate results close to those specified in the TPC Technical Design Report.

physics.ins-det↗

arXiv2001

Search for the Jacobi Instability in Rapidly Rotating 46Ti* Nuclei

The possible existence of Jacobi shape transition in hot 46Ti at high angular momenta was investigated with the Giant Dipole Resonance exclusive experiments. The GDR spectra and the angular distributions are consistent with predictions of the thermal shape fluctuation model indicating elongated nuclear shapes.

nucl-ex↗

arXiv1997

Coulomb Effects on Particle Spectra in Relativistic Nuclear Collisions

Coulomb effects on $π^\pm$ and $K^\pm$ spectra in relativistic nuclear collisions are investigated. At collision energies around 1 GeV the ratio of $π^-$ to $π^+$ is enhanced several times at low transverse momenta but less at ultrarelativistic energies. We describe the ratios at SIS, AGS and SPS energies with simple analytic models as well as more elaborate numerical models incorporating the expansion dynamics. The Coulomb effect depends on the properties of the source after the violent collision phase and provides information on source sizes, freeze-out times, and expansion velocities. Comparison with results from HBT analyses are made. Predictions for $π^\pm$ and $K^\pm$ at RHIC and LHC energies are given.

nucl-th↗