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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

Update on the CeC PoP 704 MHz 5-cell cavity cryomodule design and fabrication

A 5-cell SRF cavity operating at 704 MHz will be used for the Coherent Electron Cooling Proof of Principle (CeC PoP) system under development for the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. The CeC PoP experiment will demonstrate the new technique of cooling proton and ion beams that may increase the beam luminosity in certain cases, by as much as tenfold. The 704 MHz cavity will accelerate 2 MeV electrons from a 112 MHz SRF gun up to 22MeV. This paper provides an overview of the design, the project status and schedule of the 704 MHz 5-cell SRF for CeC PoP experiment.

43 PARTICLE ACCELERATORS↗
DOE OSTI2016

Υ production in U + U collisions at s N N = 193 GeV measured with the STAR experiment

We present a measurement of the inclusive production of ¡ mesons in U+U collisions at √sNN = 193 GeV at mid-rapidity (|y| < 1). Previous studies in central Au+Au collisions at √sNN = 200 GeV show a suppression of ¡(1S+2S+3S) production relative to expectations from the ¡ yield in p+p collisions scaled by the number of binary nucleon-nucleon collisions (N coll ), with an indication that the ¡(1S) state is also suppressed. The present measurement extends the number of participant nucleons in the collision (N part ) by 20% compared to Au+Au collisions, and allows us to study a system with higher energy density. We observe a suppression in both the ¡(1S+2S+3S) and ¡(1S) yields in central U+U data, which consolidates and extends the previously observed suppression trend in Au+Au collisions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

BNL 56 MHz HOM Damper Prototype Fabrication at JLab

A prototype Higher-Order Mode (HOM) Damper was fabricated at JLab for the Relativistic Heavy-Ion Collider's (RHIC) 56 MHz cavity at Brookhaven National Laboratory (BNL). Primarily constructed from high RRR Niobium and Sapphire, the coaxial damper presented significant challenges in electron-beam welding (EBW), brazing and machining via acid etching. The results of the prototype operation brought about changes in the damper design, due to overheating braze alloys and possible multi-pacting. Five production HOM dampers are currently being fabricated at JLab. This paper outlines the challenges faced in the fabrication process, and the solutions put in place.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Development of Magnesium Diboride Superconducting Coils for Nuclear Physics Application

The primary objective of this project is to develop an affordable magnet technology at 10-25K and then take it to a level that it can be considered mature enough to be used in a real Nuclear Physics accelerator system. We believe that because of the lower cost of magnesium diboride (MgB2) as compared to the other HTS, it offers the best such chance. Once successfully demonstrated, this exciting and innovative technology could potentially revolutionize the field the same way the conventional superconducting NbTi magnets did several decades ago. MgB2 magnets could reduce the cost of ownership (capital +operation) while enhancing performance. Another innovation is the overall cooling scheme where the exhaust gas of an existing superconducting magnet cools the inner tube which conduction cools the MgB2 coils. In several instances during the upgrade of existing facilities or designing new facilities in the Nuclear Physics or High Energy Physics communities, it is found that magnets made neither with copper coils nor with conventional superconducting NbTi coils offer an acceptable solution. Whereas copper coils limit the performance of the machine and consume large amount of power, NbTi require 4 K cryogenic facilities. This is particularly applicable in those Nuclear Physics machines where the magnetic field requirements are rather modest. One such case has been found in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) where an e-lens system is under construction to increase RHIC luminosity. In this case, magnesium diboride (MgB2) operating at 10-25 K seems to offer an exciting and practical solution. The main objective in Phase II is to demonstrate the reliability and robustness of the MgB2 coil technology, so that it is ready for use in RHIC and other user facilities. We will do this by fabricating several MgB2 coils and by conducting an exhaustive series of lifetime cycle tests. The tests will involve about a thousand ramp-up and ramp-down cycles, about 20 over current or thermal-excursions hitting the quench limit and about 10 thermal cycles. Phase II will begin with a design modeling effort of the MgB2 coils for the e-lens system with enough detail so that the magnetic, thermal and stress requirements can be understood for the fabrication and testing of representative MgB2 coils. After the technology is proven in Phase II for reliability, we will propose to use this in Phase III to upgrade RHIC e-lens system for improved luminosity performance and expect that more applications will follow in other accelerator and medical facilities.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2026

Beam test results of the Intermediate Silicon Tracker for sPHENIX

The Intermediate Silicon Tracker (INTT), a two-layer barrel silicon strip tracker, is a key component of the tracking system for sPHENIX at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. The INTT is designed to enable the association of reconstructed tracks with individual RHIC bunch crossings. To evaluate the performance of preproduction INTT ladders and the readout chain, a beam test was conducted at the Research Center for Accelerator and Radioisotope Science, Tohoku University, Japan. This paper presents the performance of the INTT evaluated through studies of the signal-to-noise ratio, residual distribution, spatial resolution, hit-detection efficiency, and multiple track reconstruction.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2015

Proceedings of RIKEN BNL Research Center Workshop: Theory and Modeling for the Beam Energy Scan: From Exploration to Discovery (Volume 121)

The Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory has concluded phase I of its Beam Energy Scan (BES) program. The goal of the RHIC BES program is to explore the phase diagram of strongly interacting matter at high baryonic densities and search for the QCD critical point by performing systematic scans at lower beam energies. Results from the RHIC BES I program are intriguing. There indeed seem to be several signals suggesting a softening of the equation of state, which may result from a first-order transition, as well as possible indications of a critical point. In light of these intriguing results, several accelerator and detector upgrades have been planned to conduct the phase II of the RHIC BES during the period 2017-2020. The goal of the RHIC BES II is discovery of the QCD critical point by performing high luminosity scans within the interesting beam energy range revealed through explorations at RHIC BES I. Past experience has proven that even qualitative understanding of the physics encoded within the RHIC experimental data requires substantial theoretical input based on QCD calculations as well as detailed, quantitative modeling of the medium created at the RHIC. However, the coordinated theoretical and modeling efforts necessary for comprehensive understanding of the RHIC BES data is presently lacking. The purpose of this workshop was to gather a small group of expert theorists, phenomenologists and experimentalists to identify the necessary theoretical and modeling developments required for RHIC BES, to delineate a clear path towards extracting concrete physics utilizing the RHIC BES data, and to kick-start collaborations among theorists, phenomenologists and experimentalists to ensure that the necessary theoretical and modeling developments can be achieved before the start of the RHIC BES II experimental program.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2015

Au intensity enhancement for RHIC

In this article, possible improvement related to the AGS 6-3-1 bunch merge test is presented. After that, relevant issues for beams with larger longitudinal emittance at RHIC are discussed.

43 PARTICLE ACCELERATORS↗
DOE OSTI2018

Toward Understanding the QGP with the STAR Experiment at RHIC

By accelerating heavy atomic nuclei (ions) to very large energies and then colliding these heavy ions at points where large particle detectors are positioned, the Relativistic Heavy Ion Collider (RHIC) provides the laboratory for studying nuclear matter under extreme conditions. It is under these extreme conditions that the matter is expected to undergo a phase transition, “melting” the protons and neutrons into their more fundamental constituents (quarks and gluons). The resulting state of matter is the so-called Quark Gluon Plasma (QGP) phase and is believed to have existed in the early universe, briefly after the Big Bang, before it cooled and formed into the matter that we know today. RHIC, at Brookhaven National Laboratory, has been providing high-energy heavy-ion collisions since the year 2000. One of the particle detectors at RHIC is called the Solenoidal Tracker at RHIC (STAR). New sub-detectors within the STAR experiment are capitalizing on the high collision rates currently provided by RHIC, allowing the experiment to select and record certain rare physics observables. The production of rare particles requires a large amount of energy and thus occurs early in a heavy-ion collision, allowing those rare particles to experience the full evolution of the collision, including the medium creation under extreme (hot and dense) conditions and subsequently the cooling and expansion of the matter. The rare particles therefore serve as probes of the medium created. Two rare-probe measurements will be investigated in this project: 1) particles resulting from scatterings of quarks and gluons with a large energy transfer in the early stage of a heavy-ion collision, and 2) particles that are made up of heavy-quark pairs. The study of such rare probes can provide information about the density and temperature of the medium created at RHIC.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2018

The experimental study of the phase structure of strongly interacting matter

Over the duration of the project period, our research has been focused on the beam energy scan data conducted at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory in order to search for the location of the Critical End Point (CEP) temperature or cross-over in the nuclear phase diagram using the STAR detector at RHIC and to determine the Equation of State (EOS) and the QGP transport coefficients. Working at the RHIC early on, we discovered the Long Range forward-backward multiplicity Correlations (LRC) which quantitatively confirmed the predictions of saturation models, in particular, the Color Glass Condensate (CGC) and the Color String Percolation Model (CSPM). We have used the CSPM to extract the initial temperature from the data. The clustering of color sources may be the way to achieve thermalization in A-A and N-N collisions. Recently we also used CSPM to measure the shear viscosity to entropy ratio at RHIC and LHC temperatures. The ratios are in agreement with values expected for a strongly interacting QGP. The thermodynamic quantities,temperature and the equation of state are in agreement with lattice QCD.

42 ENGINEERING↗
DOE OSTI2016

Elliptic flow due to charged hadrons for Au+Au collisions at RHIC energy 62.4 GeV

Elliptic flow is an important observable in search of Quark Gluon Plasma. The elliptic flow parameter dependence on centrality due to charged hadrons were studied using events generated by event generator AMPT at center of mass energy of 62.4 GeV per nucleon pair for Au+Au collisions. This study performed for pseudorapidity range from −0.35 to 0.35 and transverse momentum bins p{sub t} = 0.2 to 1 GeV/c and 1 to 2 GeV/c. We compared the results obtained from simulated data and RHIC-PHENIX data.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2018

Light Meson Production in Heavy Ion Collisions in the PHENIX Experiment

Production of a strongly interacting quark−gluon plasma (QGP) has been established in central heavy ion collisions during the studies carried out at the RHIC collider. The experiments on interactions of asymmetric nuclei (Cu + Au, U + U) provide the means to study systematically a jet quenching effect, which is a signature of QGP formation. In this paper, the factors of nuclear modification of π{sup 0} and η mesons in Cu + Au and U + U collisions at 200 GeV measured in the PHENIX experiment at RHIC are presented.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2022

A numerical evaluation of the ambient air temperature in the Electron-Ion Collider tunnel

The Electron-Ion Collider (EIC) is a next-generation collider-accelerator that may require consistent operating temperature conditions for the beams within the accelerator tunnels to maintain stable operation. Variations in ambient temperature within the tunnel can cause thermal expansion of beampipe and component supports and can negatively affect the tunnel equipment, impacting the stability of the beamline. Modifications will be made to the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) to create the EIC, which necessitates a temperature model that addresses these modifications. To approach this problem, the consistency of temperature changes in different tunnel sections was first evaluated by plotting RHIC tunnel temperature data at various times of the day and year. From this data, a tunnel section was selected and a 2D temperature model was created for RHIC, EIC, and EIC with added cooling configurations. Soil temperature data was analyzed to determine the maximum, average, and mode soil temperatures, which were used as boundary conditions in different temperature scenarios. Computational fluid dynamics modeling was used to create 2D temperature profiles for the configurations. From this model, the predicted temperatures indicate that further analysis is required to validate the boundary conditions and benchmark the current conditions to allow the prediction of the tunnel ambient conditions at EIC. This research can be used as a preliminary model to create an EIC tunnel cooling system that will increase the operational stability of the EIC. As a result of my work this summer, I have become familiar with computational fluid dynamics, including creating fluid dynamic simulations using ANSYS Fluent and related software. I have also learned about the project process required for planning large-scale engineering projects.

43 PARTICLE ACCELERATORS↗
DOE OSTI2015

Experimental demonstration of interaction region beam waist position knob for luminosity leveling

In this paper, we report the experimental implementation of the model-dependent control of the interaction region beam waist position (s * knob) at Relativistic Heavy Ion Collider (RHIC). The s * adjustment provides an alternative way of controlling the luminosity and is only known method to control the luminosity and reduce the pinch effect of the future eRHIC. In this paper, we will first demonstrate the effectiveness of the s * knob in luminosity controlling and its application in the future electron ion collider, eRHIC, followed by the detail experimental demonstration of such knob in RHIC.

43 PARTICLE ACCELERATORS↗
DOE OSTI2015

Longitudinal impedance of RHIC

The longitudinal impedance of the two RHIC rings has been measured using the effect of potential well distortion on longitudinal Schottky measurements. For the blue RHIC ring Im(Z/n) = 1.5±0.2Ω. For the yellow ring Im(Z/n) = 5.4±1Ω.

43 PARTICLE ACCELERATORS↗
DOE OSTI2023

The mapping & avoidance of high order cavity modes

In this paper a technique developed in 2016 is presented for mapping the multidimensional, multi-mode high order mode landscape of a beam driven super conducting RF cavity. The initial use case for this technique was intended to allow longitudinal gradient control of a beam driven super conducting cavity while simultaneously avoiding many dangerous high order modes and excessive component stresses. This paper will focus on the stability and component stress considerations of the 56MHz superconducting cavity, located in the 4 o’clock sector interaction region of the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. The 56MHz cavity is intended to work in conjunction with the Stochastic Cooling system to improve the longitudinal confinement in the central 197MHz RF bucket and thus increase the integrated luminosity during heavy ion beam runs at RHIC.

43 PARTICLE ACCELERATORS↗