Bulletin of the American Physical Society
2007 Annual Meeting of the Division of Nuclear Physics
Volume 52, Number 10
Wednesday–Saturday, October 10–13, 2007; Newport News, Virginia
Session HH: Instrumentation II |
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Chair: Matthias Perdekamp, University of Illinois at Urbana-Champaign Room: Newport News Marriott at City Center Blue Point I |
Saturday, October 13, 2007 9:00AM - 9:12AM |
HH.00001: HIE-ISOLDE R. Kruecken, P. Butler, M. Huyse, D. Jenkins, M. Lindroos, K. Riisager, W.B. Walters The HIE-ISOLDE project proposal is a major staged upgrade to the existing REX accelerator facility at ISOLDE with the objective to provide radioactive beams up to 5.5 MeV/u with a future option of going to 10 MeV/u. The ambition is to make all isotopes produced at ISOLDE ($>$800) available as post accelerated beams. The beam quality will be much improved for ISOLDE users with the installation of a RFQ cooler, a new improved resonant laser ionization system and a renovated high resolution mass separator. New isotopes will be made available through target and ion source development. The driver intensity will be increased (5x), with a first increase coming from a faster cycling of the PS Booster and a later increase coming from the new Linac-4. The project is designed as a participative project with many sub-tasks in which ISOLDE users are invited to participate. So far, the development and construction of an improved resonant laser ionization system, the construction of an RFQ cooler, and the prototyping of the SC linac are well advanced. We will in this contribution review the project and report on the present status of the staged proposal. [Preview Abstract] |
Saturday, October 13, 2007 9:12AM - 9:24AM |
HH.00002: Current Status of HELIOS Jon Lighthall We are currently in the process of assembling and testing the HELIcal Orbit Spectrometer (HELIOS) at the ATLAS facility of Argonne National Laboratory. HELIOS is designed to study inverse-kinematic nucleon transfer reactions using exotic beams. These reactions are of particular interest in the studies of nuclear structure away from stability, and in nuclear astrophysics. This new type of spectrometer features a 3 Tesla, 90 cm bore superconducting solenoid. Inside the HELIOS solenoid will be a hollow detector along the magnetic field axis, in-line with the target. The detector consists of a four sided, forty-element array of position-sensitive silicon detectors. This geometry has significant advantages over conventional detectors. HELIOS will be used with secondary in-flight beams produced at ATLAS, and in the future with beams from the CARIBU (CAlifornium Rare Isotope Beam Upgrade) source. The current status of HELIOS will be presented. [Preview Abstract] |
Saturday, October 13, 2007 9:24AM - 9:36AM |
HH.00003: NIMROD Upgrade S. Wuenschel, K. Hagel, Z. Kohley, L. May, J.B. Natowitz, R. Wada, S.J. Yennello The 4 pi detection array NIMROD has been recently upgraded. The upgrade increased granularity in the backward direction and improved Si coverage. NIMROD is now composed of 10 forward annular rings ($\sim $3-90 degrees) and a hemisphere of the ISiS array (90-176 degrees). There is complete Si coverage in the regions of 3-45 and 90-176 degrees. The forward region is composed of ten telescopes of 300 micron Si and CsI as well as two super telescopes of 150 and 500 micron Si with CsI per ring. The ISiS portion has complete Si coverage in the form of 500 micron Si with the CsI. Additionally, modular treatment of signals has been implemented. Handling signals in this way retains the telescope grouping of detectors in the electronics as long as possible. Towards this end, motherboards holding Zepto System preamplifiers were installed on the reaction chamber for preamplification of the Si signals at the earliest opportunity. The improved detector system has been used in a first experiment with 86,78Kr+64,58Ni systems. Performance of the detector system during the experiment will be presented. [Preview Abstract] |
Saturday, October 13, 2007 9:36AM - 9:48AM |
HH.00004: Determining the Composition of Radioactive Hotspots in the Third Phase of SNO Brent VanDevender The third and final phase of the Sudbury Neutrino Observatory (SNO) was distinguished from earlier phases by the addition of 40 $^3$He-filled proportional counters. Despite great efforts to ensure the cleanliness of construction and installation, early analysis of Cerenkov light revealed three radioactive hotspots on the proportional counter bodies. We present two new methods employed to determine the composition and activity of these spots and their contributions to SNO's solar neutrino neutral-current interaction backgrounds. [Preview Abstract] |
Saturday, October 13, 2007 9:48AM - 10:00AM |
HH.00005: Instrumentation of PrimEx Experimental Apparatus Pawel Ambrozewicz A state-of-the-art experimental setup was assembled in the Hall B of Jefferson Lab. A hybrid calorimeter, consisting of a multichannel lead glass detector with segmented high-resolution lead tungstate insert was coupled with a quasi-monochromatic photon beam from the Jefferson Lab Hall B tagged photon facility. Aided by a photon flux monitoring system, the pair spectrometer, this apparatus allows precise measurements of position and energy of forward going particles. This device was recently used in a precision measurement of neutral pion lifetime that was carried out at the Jefferson Lab - the PrimEx experiment. The measurement tested one of the most fundamental symmetry predictions of Quantum Chromodynamics, the axial anomaly, via the Primakoff effect, coherent $\pi^0$ production off a nuclear Coulomb field. Data collected covered a range of photon energies and angles that allowed clean separation of the Primakoff contribution from competing photoproduction processes. Similar setup would be used to investigate the Primakoff effect in photoproduction of the $\eta$ meson in the 12GeV energy regime of the Jefferson Lab. [Preview Abstract] |
Saturday, October 13, 2007 10:00AM - 10:12AM |
HH.00006: Precise Determination of Total Absolute Gamma Ray Intensity at HI$\gamma$S S. Stave, M.W. Ahmed, M.A. Blackston, M.D. Busch, M. Emamian, S.S. Henshaw, C.R. Howell, J. Li, S. Mikhailov, B.A. Perdue, G. Swift, H.R. Weller, Y.K. Wu Precision determination of cross sections requires precise knowledge of the incident $\gamma$-ray intensity. For this purpose, six precision machined copper attenuators have been installed in the beamline of the High Intensity Gamma Source (HI$\gamma$S) located on the Duke University campus. Each of the attenuators is individually mounted and controlled remotely. To decrease background, the attenuator system is located near the exit of the storage ring about 50 meters from the location of the target. The Cu attenuation coefficients were determined for several $\gamma$-ray energies between 2.3 MeV and 40 MeV and then the attenuated beam intensity was measured in a 10x14 inch NaI detector. Different combinations of the attenuators were used to test their effect on the $\gamma$-ray beam looking for differences in counts and resolution. Then the total, unattenuated intensity was calculated using the deadtime corrected integrated peak counts from the NaI along with the measured Cu attenuation coefficients. The results for attenuation coefficients and total intensity are in good agreement with existing attenuation data, intensity calculations and known cross sections. A detailed analysis of the uncertainties in the measured intensities will be presented along with a description of the system. [Preview Abstract] |
Saturday, October 13, 2007 10:12AM - 10:24AM |
HH.00007: The PHENIX Silicon Vertex Detector Upgrade Eric Mannel The PHENIX experiment is designed to the study the properties of the dense nuclear matter created in relativistic heavy ion collisions. In order to enhance the physics capabilities of the PHENIX detector, a silicon vertex detector (VTX) is being constructed to provide precise tracking and vertex reconstruction over the full rapidity and azimuthal range of the central spectrometer. By identifying displaced decay vertices, the VTX will be able to identify heavy quark production in proton-proton and heavy ion collisions. In addition, the VTX will be able to reconstruct jets over a large acceptance. The VTX is comprised of a four-layer barrel, with two inner pixel sensor layers and two outer strip sensor layers. This presentation will provide details of the physics capability added to PHENIX by the VTX, the technology choices of the design, and the current status of the project. [Preview Abstract] |
Saturday, October 13, 2007 10:24AM - 10:36AM |
HH.00008: The FVTX upgrade detector at PHENIX Hubert van Hecke A forward silicon detector is being designed for PHENIX. The device will cover pseudorapidities +-(1.2-2.4), matching the acceptence of the muon detectors, and is designed to greatly enhance the heavy-flavor phyics capabilities of the experiment. The FVTX will consist of two sets of four disks of silicon mini-strips, with a fast readout system that will allow input to the level-1 trigger. I will describe the proposed device, and show results from a prototype readout chain. [Preview Abstract] |
Saturday, October 13, 2007 10:36AM - 10:48AM |
HH.00009: Design and Performance of Reaction Plane Detector in PHENIX Rui Wei Measuring the event anisotropy of nucleus-nucleus collisions is one of the most important methods to investigate the hot dense partonic matter produced at RHIC. Along with the discovery of jet suppression, the observation of large $v_2$ leads to the conclusion that the strongly coupled medium is formed in Au+Au collisions. However, the $v_2$ measurements of rare observables such as electrons, photons, $J\psi$ and high p$_T$ particles are constrained by the low statistics and reaction plane resolution. By installing a new reaction plane detector at PHENIX, the resolution is improved by factor of 2. This enables us to further study the $v_2$ of rare probes and even to extend our view to $v_4$. In the talk the performance of this new detector in this year's run will be discussed. [Preview Abstract] |
Saturday, October 13, 2007 10:48AM - 11:00AM |
HH.00010: High $p_T$ PID using Time-of-Flight with Multi-gap Resistive Plate Ronald Belmont In Run7 of RHIC the PHENIX experiment operated a Time-of-Flight detector based on Multi-Gap Resistive Plate Chambers. The detector covers an area of 8 $m^2$ in the PHENIX West arm spectrometer and together with the previously installed Aerogel Cherenkov Counters (ACC) completes the high-$p_T$ particle identification (PID) upgrade in PHENIX. Intrinsic detector timing resolution of $\sigma_t ~ 80$ ps has been achieved, which allows for 4 $\sigma$ $\pi/K$ separation up to $p_T ~ 3$ GeV/$c$ and $K/p$ separation up to $p_T ~ 5 $ GeV/$c$. Combined with ACC, the new detector system provides seamless PID for $\pi/K/p$ in the range $0.2< p_T < 9$ GeV/$c$. The PID for resonances has been extended to even higher ( $> 10 $ GeV/$c$ ) $p_T$. The track-by-track identification with increased angular coverage allows for jet correlation measurements with PID in both the near side and away side jet cones. Jets have been shown to be significantly modified in heavy ion collisions at RHIC when compared to the p+p reference data. Identified particle measurements at high $p_T$ are a key to understanding the underlying jet suppression mechanisms. The MRPC-TOF performance and the extended physics capabilities of PHENIX will be discussed. [Preview Abstract] |
Saturday, October 13, 2007 11:00AM - 11:12AM |
HH.00011: Pressure and temperature dependence of gas amplification gains in R134a-isobutane-SF6 mixtures for RPCs John Wood The PHENIX first level muon trigger upgrade will include dedicated muon tracking spectrometers based on resistive plate chamber (RPC) technology. We have studied the pressure and temperature dependence of gas amplificiation in typical gas mixtures expected for the RPC application in PHENIX. [Preview Abstract] |
Saturday, October 13, 2007 11:12AM - 11:24AM |
HH.00012: Design and R\&D for the PHENIX Muon Trigger RPCs Young Jin Kim Resistive Plate Chambers (RPCs) have been widely used for trigger or time-of-flight applications in high energy physics and nuclear physics experiments. The PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) upgrades its first level muon trigger with tracking stations of double-gap RPCs. This will make it possible to study flavor separated quark and anti-quark polarizations of the proton by measuring the spin dependent yields of W-bosons in polarized proton-proton collisions. The RPC design for the PHENIX muon trigger is based on technology developed for the CMS endcap muon trigger RPCs. In this talk we introduce the general detector design and discuss the results of RPC detector performance R\&D carried out at several PHENIX institutions with different prototypes, including prototypes manufactured in the CMS RPC factory at Korea University in Seoul. [Preview Abstract] |
Saturday, October 13, 2007 11:24AM - 11:36AM |
HH.00013: A Cosmic Ray Test Stand for the PHENIX Muon Trigger RPCs Beau Meredith Resistive Plate Chambers (RPC's) will be used in the first level muon trigger for W events in the PHENIX detector at RHIC. As technology for the upgrade PHENIX has chosen fast CMS muon trigger bakelite RPCs. In order to understand RPC's and to gain experience in operating them, institutions within the PHENIX collaboration have undertaken an intense research effort in which they both develop and test RPC's. In this presentation we will describe the cosmic ray test stand setup at the University of Illinois at Urbana and present some of the results we have obtained. In particular, we shall present results for the efficiency, position resolution, timing resolution, and cluster size for RPC prototypes developed at UIUC. [Preview Abstract] |
Saturday, October 13, 2007 11:36AM - 11:48AM |
HH.00014: Near-Real Time Reconstruction of Minimum Bias Au+Au collisions at $\sqrt{s_{NN}}$=200 GeV Using Remote Computer Resources Through GRID Networking Brian Love Near-real time reconstruction of minimum bias Au+Au collision data at $\sqrt{s_{NN}}$=200 GeV from the PHENIX experiment at RHIC has been sustained over a 7 week period, proving the feasibility of future longer duration efforts. CPU resources from the ACCRE computing facility at Vanderbilt University were used for data production, while the Open Science GRID infrastructure was utilized for large volume data transfers to and from the RHIC Computing Facility (RCF). During this trial, raw data files were transferred daily from PHENIX to ACCRE and, through an automated pipeline, the files were processed and the output returned to RCF just days later at a rate of 5TB a week. Fault tolerant mechanisms were developed to ensure a robust operation with an absolute minimum of manual intervention. With the incorporation of this facility into PHENIX data processing, the power of GRID networking to combine computing resources from diverse geographical locations has been confirmed. With fast analysis turnaround of raw data, more opportunities are provided for near-real time decision making in PHENIX. [Preview Abstract] |
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