Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “GeV”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 865 records · Page 48
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

An Investigation into the Electromagnetic Interactions between a Superconducting Torus and Solenoid for the Jefferson Lab 12 GeV Upgrade

The Jefferson Lab 12 GeV Upgrade in Hall B will need CLAS12 detector that requires two superconducting magnets. One is a magnet system consisting of six superconducting trapezoidal racetrack-type coils assembled in a Toroidal configuration (Torus) and the second is an actively shielded solenoidal magnet (Solenoid). Both the torus and solenoid are located in close proximity to one another and are surrounded by sensitive detectors. This paper investigates the electromagnetic interactions between the two systems during normal operation as well as during various fault scenarios as part of a Risk Assessment and Mitigation (RAM).

Torus, actively shielded, Solenoid, SSC-NbTi,Ruthe↗
DOE OSTI2014

Electromagnetic and Mechanical Analysis of the Coil Structure for the CLAS12 Torus for 12 GeV Upgrade

The torus magnet for the CLAS12 spectrometer is a 3.6 T superconducting magnet being designed and built as part of the Jefferson Lab 12 GeV Upgrade. The magnet consists of six coil case assemblies mounted to a cold central hub. The coil case assembly consists of an aluminum case and cover enclosing an epoxy vacuum impregnated coil pack. The coil pack consists of a 117 turn double-pancake winding wrapped with 2 layers of 0.635 mm thick copper cooling sheets. The coil case assembly is cooled by supercritical helium at 4.6 K. This report details the structural analysis of the coil case assembly and the assessment of the coil pack stresses. For the normal operation of the torus magnet, the coil case assembly was analyzed for cool down to 4.6 K and the Lorentz forces at normal operating current. In addition to the normal operating configuration, the coil case assembly was analyzed for Lorentz forces arising from coil misalignment and current imbalances. The allowable stress criteria for the magnet followed the approach of the ASME codes. Primary stresses were limited to the lesser of 2/3 times the yield strength or 1/3 times the ultimate tensile strength. Primary plus secondary stresses were limited to 3 times the primary stress allowable. The analysis was performed using ANSYS Maxwell to calculate the magneto-static loads and ANSYS Mechanical to calculate the stresses.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2016

Overview of torus magnet coil production at Fermilab for the Jefferson Lab 12-GeV Hall B upgrade

Fermi National Accelerator Laboratory (Fermilab) fabricated the torus magnet coils for the 12 GeV Hall B upgrade at Jefferson Laboratory (JLab). The production consisted of 6 large superconducting coils for the magnet and 2 spare coils. The toroidal field coils are approximately 2 m x 4 m x 5 cm thick. Each of these coils consists of two layers, each of which has 117 turns of copper-stabilized superconducting cable which will be conduction cooled by helium gas. Due to the size of the coils and their unique geometry, Fermilab designed and fabricated specialized tooling and, together with JLab, developed unique manufacturing techniques for each stage of the coil construction. In conclusion, this paper describes the tooling and manufacturing techniques required to produce the six production coils and two spare coils needed by the project.

43 PARTICLE ACCELERATORS↗
DOE OSTI2017

Superconducting Magnet Power Supply and Hard-Wired Quench Protection at Jefferson Lab for 12 GeV Upgrade

The superconducting magnet system in Hall B being designed and built as part of the Jefferson Lab 12 GeV upgrade requires powering two conduction cooled superconducting magnets - a torus and a solenoid. The torus magnet is designed to operate at 3770 A and solenoid at 2416 A. Failure Modes and Effects Analysis (FMEA) determined that voltage level thresholds and dump switch operation for magnet protection should be tested and analyzed before incorporation into the system. The designs of the quench protection and voltage tap sub-systems were driven by the requirement to use a primary hard-wired quench detection sub-system together with a secondary PLC-based protection. Parallel path voltage taps feed both the primary and secondary quench protection sub-systems. The PLC based secondary protection is deployed as a backup for the hard-wired quench detection sub-system and also acts directly on the dump switch. Here, we describe a series of tests and modifications carried out on the magnet power supply and quench protection system to ensure that the superconducting magnet is protected for all fault scenarios.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2014

Recent STAR results on W production and asymmetry in polarized p-vector + p-vector collisions at √r = 500 GeV

The production of W± bosons in longitudinally polarized proton + proton collisions at RHIC is a unique way to study the flavor-dependent spin structure of the proton, since at leading order it couples directly and exclusively to specific quark flavor pairings: u+ d-bar →W{sup +} and u-bar +d→W{sup −}. Measurement of the longitudinal single-spin asymmetry of the electron decay daughters in W production is sensitive to the polarizations of the quarks involved. Results: from the first proton-proton collisions at √r = 500 GeV in 2009 are presented, along with a discussion of the forward-rapidity tracking upgrade.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2014

Longitudinal spin transfer to Λ and Λ-bar in polarized proton-proton collisions at √s = 200 GeV at STAR

The longitudinal spin transfer D {sub LL }of Λ and Λ-bar hyperons is expected to be sensitive to the helicity distribution function of strange (anti-)quarks, and to the polarized fragmentation functions. We report new results on D {sub LL }, extracted from √s = 200 GeV polarized pp collisions recorded at the STAR detector during the 2009 RHIC run. These new results cover mid-rapidity |η| < 1.2, with extended p {sub T }up to 6 GeV/c.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

Comparison between ūu and d̄d productions by the γp → π{sup −}Δ{sup ++} and π{sup +}Δ{sup 0} reactions at forward π angles at E{sub γ} = 1.5–3.0 GeV

Photoproduction reactions are dominated by isospin rules. In the case of πΔ photoproduction on the proton at forward π angles, the exchange of isospin = 1 meson(π or ρ) in the t-channel is the most dominant reaction mechanism, which is considered to give a cross section ratio σ(π{sup +}Δ{sup 0})/σ(π{sup −}Δ{sup ++}) of 1/3. The cross section ratio has not been measured precisely experimentally. We present preliminary results for the cross section ratio at E{sub γ} = 1.5–3.0 GeV. Larger ratios than 1/3 measured by our experiment at LEPS/SPring-8 suggest that the d̄d productions are enhanced compared with the ūu productions in the photoproduction reactions on the proton.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

New LHC resonance with mass 750 GeV and the vacuum stability in the Standard Model

In the present talk we show that the correction to the Higgs mass coming from the bound state S of 6 t + 6 t̅ quarks, predicted early by C.D. Froggatt and ourselves, leads to the just borderline of the Standard Model vacuum stability thereby confirming the accuracy of the multiple point principle (principle of degenerate vacua), if a mass of the bound state S coincides with the mass 750 GeV of the new diphoton state recently observed by LHC.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

Heavy supersymmetry with m{sub h} = 125 GeV in the effective field theory approach

After the Higgs boson discovery at the LHC with the mass 125 GeV a number of MSSM scenarios has been proposed to separate suitable domains of the parameter space. In the framework of two scenarios we demostrate possible reduction of multidimentional MSSM parameter space and analyse precise restrictions imposed on it.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

Analysis of pion production data measured by HADES in proton-proton collisions at 1.25 GeV

Baryon resonance production in proton-proton collisions at a kinetic beam energy of 1.25 GeV is investigated. The multi-differential data were measured by the HADES Collaboration. Exclusive channels with one pion in the final state ($np\pi^+$ and $pp\pi^0$ were put to extended studies based on various observables in the framework of a one-pion exchange model and with solutions obtained within the framework of a partial wave analysis (PWA) of the Bonn-Gatchina group. The results of the PWA confirm the dominant contribution of the $\Delta(1232)$, yet with a sizable impact of the $N(1440)$ and non-resonant partial waves.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2015

Critical fluctuations of the proton density in A+A collisions at 158A GeV

Here, we look for fluctuations expected for the QCD critical point using an intermittency analysis in the transverse momentum phase space of protons produced around midrapidity in the 12.5 % most central C+C, Si+Si and Pb+Pb collisions at the maximum SPS energy of 158A GeV. We find evidence of power-law fluctuations for the Si+Si data. The fitted power-law exponent Φ 2 =0.96 +0.38 –0.25 (stat.) ± 0.16 (syst.) is consistent with the value expected for critical fluctuations. Power-law fluctuations had previously also been observed in low-mass π + π – pairs in the same Si+Si collisions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

Diphoton excess at 750 GeV: gluon–gluon fusion or quark–antiquark annihilation?

Recently, ATLAS and CMS collaborations reported an excess in the measurement of diphoton events, which can be explained by a new resonance with a mass around 750 GeV. In this work, we explored the possibility of identifying if the hypothetical new resonance is produced through gluon–gluon fusion or quark–antiquark annihilation, or tagging the beam. Three different observables for beam tagging, namely the rapidity and transverse-momentum distribution of the diphoton, and one tagged bottom-jet cross section, are proposed. Combining the information gained from these observables, a clear distinction of the production mechanism for the diphoton resonance is promising.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2021

Study of energy response and resolution of the ATLAS Tile Calorimeter to hadrons of energies from 16 to 30 GeV

Three spare modules of the ATLAS Tile Calorimeter were exposed to test beams from the Super Proton Synchrotron accelerator at CERN in 2017. The detector’s measurements of the energy response and resolution to positive pions and kaons, and protons with energies ranging from 16 to 30 GeV are reported. The results have uncertainties of a few percent. They were compared to the predictions of the Geant4-based simulation program used in ATLAS to estimate the response of the detector to proton-proton events at the Large Hadron Collider. The determinations obtained using experimental and simulated data agree within the uncertainties.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2021

Measurements of ${\Xi \left( 1530\right) ^{0}} $ and ${\overline{\Xi }\left( 1530\right) ^{0}} $ production in proton–proton interactions at $\sqrt{s_{NN}}$ = 17.3 $\text{ GeV }$ in the NA61/SHINE experiment

Double-differential yields of ${\Xi \left( 1530\right) ^{0}} $ and ${\overline{\Xi }\left( 1530\right) ^{0}} $ resonances produced in p+p interactions were measured at a laboratory beam momentum of 158 $\text{ GeV }\!/\!c$. This measurement is the first of its kind in p+p interactions below LHC energies. It was performed at the CERN SPS by the NA61/SHINE collaboration. Double-differential distributions in rapidity and transverse momentum were obtained from a sample of $26\times 10^6$ inelastic events. The spectra are extrapolated to full phase space resulting in mean multiplicity of ${\Xi \left( 1530\right) ^{0}} $ ($6.73 \pm 0.25\pm 0.67)\times 10^{-4}$ and ${\overline{\Xi }\left( 1530\right) ^{0}} $ ($2.71 \pm 0.18\pm 0.18)\times 10^{-4}$. The rapidity and transverse momentum spectra and mean multiplicities were compared to predictions of string-hadronic and statistical model calculations.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Charmonium production in $p$Ne collisions at $\sqrt{s_{\scriptscriptstyle \text {NN}}} =68.5$ GeV

The measurement of charmonium states produced in proton-neon (pNe) collisions by the LHCb experiment in its fixed-target configuration is presented. The pro duction of J/ψ and ψ(2S) mesons is studied with a beam of 2.5 TeV protons colliding on gaseous neon targets at rest, corresponding to a nucleon-nucleon centre-of-mass energy $\sqrt{s_{NN}}$ = 68.5 GeV. The data sample corresponds to an integrated luminosity of 21.7 ± 1.4 nb -1 . The J/ψ and ψ(2S) hadrons are reconstructed in μ + μ - final states. The J/ψ production cross-section per target nucleon in the centre-of mass rapidity range y* ϵ [-2.29, 0] is found to be 506 ± 8 ± 46 nb/nucleon. The ratio of J/ψ and D 0 cross-sections is evaluated to (1.06 ± 0.02 ± 0.09)%. The ψ(2S) to J/ψ relative production rate is found to be (1.67 ± 0.27 ± 0.10)% in good agreement with other measurements involving beam and target nuclei of similar sizes.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Open charm production and asymmetry in p Ne collisions at $\sqrt{s_{\scriptscriptstyle {\textrm{NN}}}}$ = 68.5 GeV

A measurement of D 0 meson production by the LHCb experiment in its fixed-target configuration is presented. The production of D 0 mesons is studied with a beam of 2.5 TeV protons colliding on a gaseous neon target at rest, corresponding to a nucleon–nucleon centre-of-mass energy of $\sqrt{s_{NN}}$ = 68.5 GeV. The sum of the D 0 and $\overline{D}$ 0 production cross-section in pNe collisions in the centre-of-mass rapidity range y* ϵ [-2.29,0] is found to be $σ^{y* ϵ [-2.29,0]}_{D^0}$ = 48.2 ± 0.3 ± 4.5 μb/nucleon where the first uncertainty is statistical and the second is systematic. The D 0 and $\overline{D}$ 0 production asymmetry is also evaluated and suggests a trend towards negative values at large negative y*. The considered models do not account precisely for all the features observed in the LHCb data, but theoretical predictions including 1% intrinsic charm and 10% recombination contributions better describe the data than the other models considered.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

${{J}/\psi }$ and ${{D}} ^0$ production in $\sqrt{s_{\scriptscriptstyle \text {NN}}} =68.5\,\text {GeV} $ PbNe collisions

The first measurement of ${{J}/\psi }$ and ${{D}} ^0$ production in PbNe collisions by the LHCb experiment in its fixed-target configuration is reported. The production of ${{J}/\psi }$ and ${{D}} ^0$ mesons is studied with a beam of lead ions with an energy of 2.5 TeV per nucleon colliding on gaseous neon targets at rest, corresponding to a nucleon-nucleon centre-of-mass energy of $\sqrt{s_{\scriptscriptstyle \text {NN}}} =68.5\,\text {GeV}$. The ${{J}/\psi }$/${{D}} ^0$ production cross-section ratio is studied as a function of rapidity, transverse momentum and collision centrality. These data are compared with measurements from $p\text {Ne}$ collisions at the same energy and show no difference in the observed ${{J}/\psi }$ suppression trend when comparing $p\text {Ne}$ and PbNe peripheral collisions with PbNe central collisions. Similar content being vie

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗