Development of multi-gap resistive plate chambers with low-resistive silicate glass electrodes for operation at high particle fluxes and large transported charges
Using electrodes made of semi-conductive glass is an innovative way of improving the rate capability of resistive plate chambers. To address this issue, we developed 6- and 10-gap counters with low-resistive silicate glass electrodes (bulk resistivity ∼10 10  Ω cm) suited for time-of-flight (TOF) applications at high rates and high transported charges. Measurements were performed at GSI-Darmstadt under uniform an irradiation by secondary particles stemming from proton reactions at 2.5 GeV/A. For the 10-gap MRPC, time resolutions below 90 ps and efficiencies larger than 90% were obtained at counting rates up to 25 kHz/cm 2 . When the particle flux increases every 5 kHz/cm 2 , the efficiency decreases by 1% and the time resolution deteriorates by 4 ps. A tolerable decrease of the material conductivity was also observed for a total transported charge of 1 C/cm 2 .

title: Study on the position resolution of resistive plate chamber
abstract: A prototype RPC detector with a 2-mm readout strip pitch has been built for research into its position resolution. After determining the optimal threshold and working voltage, the efficiency and position resolution of this prototype RPC detector have been studied carefully. Using cosmic-ray muons with different directions and incident positions, we have obtained less than 0.5-mm average statistical errors of position resolution for two different RPC readout structures: 1- and 1.7-mm readout strip widths. The results show that the RPC can also give high position resolution with very little variation from its traditional structure. This will lead to possible applications of the RPC in medical imaging and other domains.

title: Performance of a new LMRPC prototype for the STAR MTD system
abstract: A new prototype of a Long-Strip Multi-Gap Resistive Plate Chamber (LMRPC) for the STAR Muon Telescope Detector (MTD) at RHIC has been developed. This prototype has an active area of 52 x 90 cm(2) and consists of six 250 mu m wide gaps. Each detector has 12 strips, read-out at both ends, which are each 3.8 cm wide and 90 cm long with 0.6 cm intervals. In cosmic-ray tests, the efficiency was larger than 95% and the time resolution was similar to 75 ps for the 94% Freon, 5% iso-butane, and 1% SF6 gas mixture. There was good uniformity in the performance across the different strips. The module was also tested in a proton beam at IHEP in Beijing. The efficiency was close to 100% and the best timing resolution achieved was 55 ps for the 90% Freon, 5% iso-butane, and 5% SF6 gas mixture. Trigger scans along and across the strip direction were also performed. Crown

title: A prototype of a high rating MRPC
abstract: Six-gap resistive plate chamber (MRPC) prototypes with semiconductive glass electrodes (bulk resistivity ~ 1010 Ωcm) were studied for suitability in time-of-flight (TOF) applications at high rates. These studies were performed using a continuous electron beam of 800 MeV at IHEP and an X-ray machine. Time resolutions of about 100 ps and efficiencies larger than 90% were obtained for flux densities up to 28 kHz/cm2.

title: Measurements of $D^{0}$ and $D^{*}$ Production in $p$ + $p$ Collisions at $\sqrt{s}$ = 200 GeV
abstract: We report measurements of charmed-hadron ($D^{0}$, $D^{*}$) production cross sections at mid-rapidity in $p$ + $p$ collisions at a center-of-mass energy of 200 GeV by the STAR experiment. Charmed hadrons were reconstructed via the hadronic decays $D^{0}\rightarrow K^{-}\pi^{+}$, $D^{*+}\rightarrow D^{0}\pi^{+}\rightarrow K^{-}\pi^{+}\pi^{+}$ and their charge conjugates, covering the $p_T$ range of 0.6$-$2.0 GeV/$c$ and 2.0$-$6.0 GeV/$c$ for $D^{0}$ and $D^{*+}$, respectively. From this analysis, the charm-pair production cross section at mid-rapidity is $d\sigma/dy|_{y=0}^{c\bar{c}}$ = 170 $\pm$ 45 (stat.) $^{+38}_{-59}$ (sys.) $\mu$b. The extracted charm-pair cross section is compared to perturbative QCD calculations. The transverse momentum differential cross section is found to be consistent with the upper bound of a Fixed-Order Next-to-Leading Logarithm calculation.

title: Three-particle coincidence of the long range pseudorapidity correlation in high energy nucleus-nucleus collisions.
abstract: We report the first three-particle coincidence measurement in pseudorapidity (Δη) between a high transverse momentum (p⊥) trigger particle and two lower p⊥ associated particles within azimuth |Δϕ|<0.7 in square root of s(NN)=200 GeV d+Au and Au+Au collisions. Charge ordering properties are exploited to separate the jetlike component and the ridge (long range Δη correlation). The results indicate that the correlation of ridge particles are uniform not only with respect to the trigger particle but also between themselves event by event in our measured Δη. In addition, the production of the ridge appears to be uncorrelated to the presence of the narrow jetlike component.

title: Determination of the neutrino mass hierarchy at an intermediate baseline
abstract: It is generally believed that neutrino mass hierarchy can be determined at a long baseline experiment, often using accelerator neutrino beams. Reactor neutrino experiments at an intermediate baseline have the capability to distinguish normal or inverted hierarchy. Recently, it has been demonstrated that the mass hierarchy could possibly be identified using Fourier transform to the L/E spectrum if the mixing angle sin(2)(2 theta(13)) > 0.02. In this study, a more sensitive Fourier analysis is introduced. We found that an ideal detector at an intermediate baseline (similar to 60 km) could identify the mass hierarchy for a mixing angle sin(2)(2 theta(13)) > 0.005, without requirements on accurate information of reactor neutrino spectra and the value of Delta m(32)(2).

title: Test results of heavily irradiated Si detectors
abstract: A large use of silicon microstrip detectors is foreseen for the intermediate part of the CMS tracker. A specific research and development program has been carried out with the aim of finding design layouts and technological solutions for allowing silicon microstrip detectors to be reliably used on a high radiation level environment. As a result of this work single sided, AC-coupled, polysilicon biased, 300 μ m thick, p + on n substrate detectors were chosen. Irradiation tests have been performed on prototypes up to fluence 2×10 14  n/cm 2 . The detector performances do not significantly change if the detectors are biased well above the depletion voltage. S / N is reduced by less than 20%, still enough to insure a good efficiency and space resolution. Multiguard structures has been developed in order to reach high voltage operation (above 500 V).

title: The high-speed after pulse measurement system for PMT
abstract: A system employing a desktop FADC has been developed to investigate the features of 8 inches Hamamatsu PMT. The system stands out for its high-speed and informative results as a consequence of adopting fast waveform sampling technology. Recording full waveforms allows us to perform digital signal processing, pulse shape analysis, and precision timing extraction. High precision after pulse time and charge distribution characteristics are presented in this manuscript. Other photomultipliers characteristics, such as dark rate and transit time spread, can also be obtained by exploiting waveform analysis using this system.

title: SLOW MAGNETOACOUSTIC WAVES OBSERVED ABOVE A QUIET-SUN REGION IN A DARK CAVITY
abstract: Waves play a crucial role in diagnosing the plasma properties of various structures in the solar corona and coronal heating. Slow magnetoacoustic (MA) waves are one of the important types of magnetohydrodynamic waves. In past decades, numerous slow MA waves were detected above active regions and coronal holes, but were rarely found elsewhere. Here, we investigate a “tornado”-like structure consisting of quasi-periodic streaks within a dark cavity at about 40–110 Mm above a quiet-Sun region on 2011 September 25. Our analysis reveals that these streaks are actually slow MA wave trains. The properties of these wave trains, including phase speed, compression ratio, and kinetic energy density, are similar to those of the reported slow MA waves, except that the period of these waves is about 50 s, much shorter than the typical reported values (3–5 minutes).

title: Letter of intent for the study of CP violation and heavy flavor physics at PEP-II