Multigap RPCs in the STAR experiment at RHIC Llope, W.J.
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
2012, 2012-1-00, Volume:
661
Journal Article
Peer reviewed
A large-area (50
m
2) Time-of-Flight system has recently been installed in the STAR experiment at RHIC. The detectors are Multigap Resistive Plate Chambers (MRPCs) and are digitized using custom ...electronics based on the CERN “NINO” and “HPTDC” chips. Several different prototype systems were built and operated in STAR from 2002 to 2006. The design and performance of the prototypes and the
∼
70
%
installed final system during the 2009 RHIC Run will be presented. A possible future upgrade to the STAR experiment is the Muon Telescope Detector (MTD). This system will use very large MRPCs with double-ended read-out to identify via time of flight the muons that pass through steel back-legs of the STAR magnet. The design of this system and the performance of MTD prototype systems will also be presented.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
We propose a large-area, cost-effective muon telescope detector (MTD) at mid-rapidity for the solenoidal tracker at the RHIC (STAR) and for the next generation of detectors at a possible electron-ion ...collider. We utilize large multi-gap resistive plate chambers with long readout strips (long-MRPC) in the detector design. The results from cosmic ray and beam tests show that the intrinsic timing and spatial resolution for a long-MRPC are 60-70 ps and ~1 cm, respectively. The performance of the prototype muon telescope detector at STAR indicates that muon identification at a transverse momentum of a few GeV/c can be achieved by combining information from track matching with the MTD, ionization energy loss in the time projection chamber and time-of-flight measurements. A primary muon over secondary muon ratio of better than 1/3 can be achieved. This provides a promising device for future quarkonium programs and primordial dilepton measurements at the RHIC. Simulations of the muon efficiency, the signal-to-background ratio of J/psi, the separation of 1S from 2S+3S states and the electron-muon correlation from charm pair production in the RHIC environment are presented.
The gamma radiation emitted from a variety of commercial decorative granites available for use in U.S. homes has been measured with portable survey meters as well as an NaI(Th) gamma spectrometer. ...The 40K, U-nat, and 232Th activity concentrations were determined using a full-spectrum analysis. The dose rates that would result from two different arrangements of decorative granite slabs as countertops were explored in simulations involving an adult anthropomorphic phantom.
► Gamma rates, spectra, and activity concentrations from decorative granites used as countertops in U.S. homes. ► Activity concentrations in Bq/kg for 40K, U-nat, and 232Th. ► Dose rates for each calculated using an anthropomorphic phantom; typical countertop geometries.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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CMK, CTK, FMFMET, IJS, NUK, PNG, UL, UM
5.
The STAR Vertex Position Detector Llope, W.J.; Zhou, J.; Nussbaum, T. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2014, Volume:
759
Journal Article
Peer reviewed
Open access
The 2×3 channel pseudo Vertex Position Detector (pVPD) in the STAR experiment at RHIC has been upgraded to a 2×19 channel detector in the same acceptance, called the Vertex Position Detector (VPD). ...This detector is fully integrated into the STAR trigger system and provides the primary input to the minimum-bias trigger in Au+Au collisions. The information from the detector is used both in the STAR Level-0 trigger and offline to measure the location of the primary collision vertex along the beam pipe and the event “start time” needed by other fast-timing detectors in STAR. The offline timing resolution of single detector channels in full-energy Au+Au collisions is ~100ps, resulting in a start time resolution of a few tens of picoseconds and a resolution on the primary vertex location of ~1cm.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The large-area time-of-flight upgrade for STAR Llope, W.J.
Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms,
December 2005, 2005-12-00, Volume:
241, Issue:
1-4
Journal Article
Peer reviewed
The STAR experiment at RHIC concentrates on the tracking of charged hadrons via ionization in gas- and silicon-based detectors, and the detection of electrons and photons via calorimetry, in a wide ...and azimuthally complete acceptance that’s unique at RHIC. STAR’s ability to directly identify the species of the tracked charged hadrons is however limited to “low” hadron momenta. Approximately 30% of the charged particles in the event at higher momenta cannot be directly identified, which hampers the physics reach of STAR in a number of key areas. To address this blind spot, STAR aims to surround the entire cylindrical surface of the tracking detectors with a large-area (∼50m2) time-of-flight (TOF) system based on the relatively new technology called the multi-gap resistive plate chamber (MRPC). Prototype TOF systems based on this technology were operated in STAR throughout the last two RHIC running periods. The design and operation of STAR’s MRPCs, the performance of the two prototype systems, and an overview of the design of the planned large-area system, will be discussed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
We report on the W and Z/γ∗ differential and total cross sections as well as the W+/W− and (W+ + W−)/(Z/γ∗) cross section ratios measured by the STAR experiment at RHIC in p + p collisions at √s = ...500 GeV and 510 GeV. The cross sections and their ratios are sensitive to quark and antiquark parton distribution functions. In particular, at leading order, the W cross section ratio is sensitive to the d/u ratio. These measurements were taken at high Q2 ∼ M2W, M2Z and can serve as input into global analyses to provide constraints on the sea quark distributions. The results presented here combine three STAR datasets from 2011, 2012, and 2013, accumulating an integrated luminosity of 350 pb−1. We also assess the expected impact that our W+ / W− cross section ratios will have on various quark distributions, and find sensitivity to the u − d and d/u distributions.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
We report high-precision measurements of the longitudinal double-spin asymmetry, ALL, for midrapidity inclusive jet and dijet production in polarized p p collisions at a center-of-mass energy of √ s ...= 200 GeV . The new inclusive jet data are sensitive to the gluon helicity distribution, Δg (x, Q2), for gluon momentum fractions in the range from x ≃ 0.05 to x ≃ 0.5, while the new dijet data provide further constraints on the x dependence of Δ g (x , Q2). The results are in good agreement with previous measurements at √ s = 200 GeV and with recent theoretical evaluations of prior world data. Our new results have better precision and thus strengthen the evidence that Δg(x,Q2) is positive for x > 0.05.
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We report the first measurements of transverse single-spin asymmetries for inclusive jet and jet+π± production at midrapidity from transversely polarized proton-proton collisions at s=500 GeV. The ...data were collected in 2011 with the STAR detector sampled from 23 pb−1 integrated luminosity with an average beam polarization of 53%. Asymmetries are reported for jets with transverse momenta 6<pT<55 GeV/c and pseudorapidity |η|<1. Presented are measurements of the inclusive-jet azimuthal transverse single-spin asymmetry, sensitive to twist-3 initial-state quark-gluon correlators; the Collins asymmetry, sensitive to quark transversity coupled to the polarized Collins fragmentation function; and the first measurement of the “Collins-like” asymmetry, sensitive to linearly polarized gluons. Within the present statistical precision, inclusive-jet and Collins-like asymmetries are small, with the latter allowing the first experimental constraints on gluon linear polarization in a polarized proton. At higher values of jet transverse momenta, we observe the first nonzero Collins asymmetries in polarized-proton collisions, with a statistical significance of greater than 5σ. The results span a range of x similar to results from semi-inclusive deep-inelastic scattering but at much higher Q2. The Collins results enable tests of universality and factorization breaking in the transverse momentum-dependent formulation of perturbative quantum chromodynamics.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
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