A TPC detector for the study of high multiplicity heavy ion collisions

Wieman, H.; Abbott, Steve; Arthur, A.; Bercovitz, J.; Bieser, F.; Harnden, C.W.; Jones, Ronald W.; Kleinfelder, S.; Lee, K.; Nakamura, Morikazu; McParland, C.; Odyniec, G.; Olson, D.; Pugh, H.G.; Rai, G.; Ritter, H. G.; Symons, T. J. M.; Wright, M.; Wright, R.E.; Rudge, A.

doi:10.1016/0375-9474(91)90396-n

Cited by 19 publications

(6 citation statements)

References 3 publications

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“…The new data were taken by the E895 Experiment [8] at nominally 2, 4, 6, and 8 AGeV (1.85, 3.91, 6.0 and 8.0 AGeV after correction for energy loss before the target) at the Brookhaven AGS using the EOS TPC [9]. Global characterization of the collisions is made possible by the nearly 4π center of mass frame coverage provided by this detector.…”

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confidence: 99%

Longitudinal Flow of Protons from(2–8)AGeVCentralAu+AuCollisions

Klay¹,

Ajitanand²,

Alexander³

et al. 2002

Phys. Rev. Lett.

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110

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Experimental heavy ion programs from the Bevalac, SIS, the AGS and the CERN SPS have attempted to characterize the distributions of particles emerging from high energy collisions in terms of simple thermodynamic principles. Testing the underlying assumptions of chemical and thermal equilibrations at different stages of the collision has been attempted by comparing model expectations to many different experimental observables. Static isotropic thermal emission models applied to observed particle rapidity distributions from experiments at all beam energies consistently fail to describe the observed shape; such model predictions being too narrow. Thermal models which include collective longitudinal expansion have been much more successful at reproducing the observed rapidity distributions [1,2]. The additional collective motion is attributed to intense pressure gradients which develop in the very hot, compressed nuclear matter fireballs created in heavy ion collisions.At the AGS, rapidity distributions of multiple particle species, including pions, kaons, protons and lambda hyperons from central collisions have been simultaneously described by a thermal distribution with a common longitudinal expansion velocity [2,3]. The agreement between the proton and other particle distributions suggests a high degree of stopping of the incident nucleons at the top AGS energy, which implies even more stopping at lower beam energies. However, recent investigations of the centrality dependence of the proton rapidity distributions from 6-11 AGeV Au+Au collisions by E917 suggest that the degree of nucleon stopping may be less than previously considered [4]. Nevertheless, their flat dN/dy for central collisions at all beam energies, fitted by sources distributed uniformly in rapidity to y-y cm = 0, could also be interpreted in the manner presented herein.For the asymptotic case at extremely high beam energies, Bjorken proposed [5] that nuclear transparency would evacuate the central rapidity region of all of the initial nucleons, leaving a hot, high-energy density region in which a Quark Gluon Plasma might form. In 160 AGeV Pb+Pb collisions at the CERN SPS, observed net proton ((+)-(-)) rapidity distributions [6] exhibit a double-humped character which is consistent with this transparency. At SPS energies, the nucleon distributions are not describable by a simple thermal model with only collective longitudinal flow, but rather need additional theoretical consideration of transparency. However, the negative hadron (mostly pions) rapidity distributions are well-described by this model, which might be interpreted as suggesting a significant amount of collective longitudinal flow for produced particles [2].

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confidence: 99%

Longitudinal Flow of Protons from(2–8)AGeVCentralAu+AuCollisions

Klay¹,

Ajitanand²,

Alexander³

et al. 2002

Phys. Rev. Lett.

Self Cite

110

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“…In the first design a powerful laser beam is focused by a demagnification telescope to ~1 mm diameter beam with the smallest waist positioned in the detector center. This beam is split by semitransparent mirrors, installed on an inner surface of the detector (ALEPH TPC [8]), or on a separate optical bench near the detector (EOS TPC [9]). There are several difficulties in this design.…”

Section: Laser System Descriptionmentioning

confidence: 99%

The laser system for the STAR time projection chamber

Abele

Berkovitz

Boehm

et al. 2003

Nuclear Instruments and Methods in Physics Research Section A:

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The Time Projection Chamber (TPC) is the core tracking detector for the STAR experiment at RHIC. To determine spatial distortions, calibrate and monitor the TPC, a laser calibration system has been built. We developed a novel design to produce ~500 thin laser beams simulating straight particle tracks in the TPC volume. The new approach is significantly simpler than the traditional ones, and provides a higher TPC coverage at a reduced cost. During RHIC 2000 and 2001 runs the laser system was used to monitor the TPC performance and measure drift velocity with ~0.02 % accuracy. Additional runs were recorded with and without magnetic field to check ExB corrections.

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“…The STAR system [3] is similar to the design used for the EOS [4] and NA-49 [5] TPC electronics. In fact, NA-49 and STAR share the SCA/ADC chip design.…”

Section: Introductionmentioning

confidence: 99%

A readout system for the STAR time projection chamber

Anderson

Bieser

Bossingham

et al. 2003

Nuclear Instruments and Methods in Physics Research Section A:

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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 (dE/dx) 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.

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A TPC detector for the study of high multiplicity heavy ion collisions

Cited by 19 publications

References 3 publications

Longitudinal Flow of Protons from(2–8)AGeVCentralAu+AuCollisions

Longitudinal Flow of Protons from(2–8)AGeVCentralAu+AuCollisions

The laser system for the STAR time projection chamber

A readout system for the STAR time projection chamber

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