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.
The STAR Barrel Electromagnetic Calorimeter Beddo, M.; Bielick, E.; Fornek, T. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2003, Letnik:
499, Številka:
2
Journal Article
Recenzirano
Details concerning the design, fabrication and performance of the STAR Barrel Electromagnetic Calorimeter are presented.
The forward time projection chamber in STAR Ackermann, K.H.; Bieser, F.; Brady, F.P. ...
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
Two cylindrical forward TPC detectors are described which were constructed to extend the phase space coverage of the STAR experiment to the region 2.5<|
η|<4.0. For optimal use of the available space ...and in order to cope with the high track density of central Au+Au collisions at RHIC, a novel design was developed using radial drift in a low diffusion gas. From prototype measurements a 2-track resolution of 1–
2
mm
is expected.
Active pixel sensor (APS) is a promising technology for next-generation vertex detectors. This paper discusses the design and testing of two generations of APS chips. Both are arrays of 128 by 128 ...pixels, each 20 by 20 /spl mu/m. Each array is divided into subarrays in which different sensor structures (4 in the first version and 16 in the second) and/or readout circuits are employed. Measurements of several of these structures under Fe/sup 55/ exposure are reported. The sensors have also been irradiated by 55 MeV protons to test for radiation damage. The radiation increases the noise and reduces the signal. The noise can be explained by shot noise from the increased leakage current, and the reduction in signal is due to charge being trapped in the epi layer. Nevertheless, the radiation effect is small for the expected exposures at RHIC and RHIC II. Finally, we describe our conception for mechanically supporting a thin silicon wafer in an actual detector.
The STAR trigger Bieser, F.S.; Crawford, H.J.; Engelage, J. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2003, Letnik:
499, Številka:
2
Journal Article
Recenzirano
We describe the trigger system that we designed and implemented for the STAR detector at RHIC. This is a
10
MHz
pipelined system based on fast detector output that controls the event selection for ...the much slower tracking detectors. Results from the first run are presented and new detectors for the 2001 run are discussed.
Development and studies of a time projection chamber with GEMs KAMINSKI, J; BALL, M; BIESER, F ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2004, Letnik:
535, Številka:
1-2
Journal Article
Three novel integrated CMOS active pixel sensor circuits for vertex detector applications have been designed with the goal of increased signal-to-noise ratio and speed. First, a large-area native ...epitaxial silicon photogate sensor was designed to increase the charge collected per hit pixel and to reduce charge diffusion to neighboring pixels. High charge to voltage conversion is maintained by subsequent charge transfer to a low capacitance readout node. Second, a per-pixel correlated double sampling kT/C reset noise reduction circuit was tested. It requires only one read, as compared to two for typical double sampling in active pixel sensors, and no off-pixel storage or subtraction is needed. The technique reduced input-referred temporal noise by a factor of 2.5 to a measured 15.6 e/sup -/, rms. Finally, a column-level active reset technique was designed that suppresses kT/C reset noise. It reduced noise by up to a factor of 7.6, to an estimated 8.3 input-referred electrons, rms. The technique also dramatically reduces fixed pattern (pedestal) noise, by up to a factor of 21. This may reduce pixel-by-pixel pedestal differences enough to permit sparse data scan without per-pixel offset corrections.
Development and studies of a time projection chamber with GEMs Kaminski, J.; Ball, M.; Bieser, F. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2004, Letnik:
535, Številka:
1
Journal Article
Recenzirano
Future high-energy physics experiments will have stringent requirements on the quality of their central tracking systems. In order to evaluate whether a Time Projection Chamber (TPC) in combination ...with a Micro-Pattern Gas Amplification stage can meet these demands, a small cylindrical prototype has been equipped with two Gas Electron Multipliers (GEMs) and micropads connected to highly integrated front-end electronics. In earlier tests with this system in high-rate particle beams—but without magnetic field—at the Proton-Synchrotron at CERN, high efficiencies and good single-pad-row spatial resolutions could be demonstrated.
We now present complementary measurements with this system in high magnetic fields up to 5
T at DESY (Hamburg, Germany). Detailed results are given for the spatial resolution dependence on parameters such as drift distance, effective gas gain and magnetic field. Transverse single-pad-row spatial resolution was found to be as low as
(
53
±
5
)
μ
m and a previously published model for the extrapolation of the beam test resulting in large scale operation conditions at the Linear Collider could be confirmed.
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.