The STAR Time Projection Chamber (TPC) is used to record the collisions at the Relativistic Heavy Ion Collider. The TPC is the central element in a suite of detectors that surrounds the interaction ...vertex. The TPC provides complete coverage around the beam-line, and provides complete tracking for charged particles within ±1.8 units of pseudo-rapidity of the center-of-mass frame. Charged particles with momenta greater than
100
MeV/c
are recorded. Multiplicities in excess of 3000 tracks per event are routinely reconstructed in the software. The TPC measures
4
m
in diameter by
4.2
m
long, making it the largest TPC in the world.
A readout system for the STAR time projection chamber Anderson, M.; Bieser, F.; Bossingham, R. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2003, Letnik:
499, Številka:
2
Journal Article
Recenzirano
Odprti dostop
We describe the readout electronics for the STAR Time Projection Chamber. The system is made up of 136,608 channels of waveform digitizer, each sampling 512 time samples at 6–12 Mega-samples per ...second. The noise level is about 1000 electrons, and the dynamic range is 800:1, allowing for good energy loss (d
E/d
x) measurement for particles with energy losses up to 40 times minimum ionizing. The system is functioning well, with more than 99% of the channels working within specifications.
We have used a novel new spectrometer to make the first observation and measurement of electron capture from ital esup +-ital esup minus pair production in relativistic heavy ion collisions. For a ...0.96 GeV/nucleon Usup 92+ beam the cross section for a Au target is 2.19(0.25) b, and the target ital Z dependence is ital Zsub ital tsup 2.8plus minus0.25. We also measured the energy and angular distributions of the of the positrons, and for comparison, the cross section for ital esup +-ital esup minus pair production without capture is 3.30(0.65) b.
We report the first measurement of the energy dependence of electron capture from electron-positron pair production in relativistic heavy ion collisions. For a Lasup 57+ beam incident on Au, Ag, and ...Cu targets at energies of 0.405, 0.956, and 1.3 GeV/u we find that the cross sections for capture from pair production and the free pair production process increase with increasing collision energy at similar rates. Combining with uranium data reported previously gives a projectile atomic number dependence for 0.956 GeV/u ions on a Au target of ital Zsub ital psup 6.54plus minus0.65 for capture from pair production and ital Zsub ital psup 1.53plus minus0.80 for the free pair production process.
Results from the STAR TPC system test Betts, W.; Bieser, F.; Bossingham, R. ...
IEEE transactions on nuclear science,
06/1997, Letnik:
44, Številka:
3
Journal Article
Recenzirano
Odprti dostop
A system test of various components of the Solenoidal Tracker at RHIC (STAR) detector, operating in concert, has recently come on-line. Communication between a major sub-detector, a sector of the ...time projection chamber (TPC), and the trigger, data acquisition and slow controls systems has been established, enabling data from cosmic ray muons to be collected. First results from an analysis of the TPC data are presented. These include measurements of system noise, electronic parameters such as amplifier gains and pedestal values, and tracking resolution for cosmic ray muons and laser induced ionization tracks. A discussion on the experience gained in integrating the different components for the system test is also given.
Measurements of dielectron production in p + p and p + d collisions with beamkinetic energies from 1.04 to 4.88 GeV are presented. The differential cross section is presented as a function of ...invariant pair mass, transverse momentum, and rapidity. The shapes of the mass spectra and their evolution with beam energy provide information about the relative importance of the various dielectron production mechanisms in this energy regime. The p + d to p + p ratio of the dielectron yield is also presented as a function of invariant pair mass, transverse momentum, and rapidity. The shapes of the transverse momentum and rapidity spectra from the p + d and p + p systems are found to be similar to one another for each of the beam energies studied. The beam energy dependence of the integrated cross sections is also presented.
Two-pion correlations in heavy ion collisions Zajc, W. A.; Bistirlich, J. A.; Bossingham, R. R. ...
Physical review. C, Nuclear physics,
06/1984, Letnik:
29, Številka:
6
Journal Article
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