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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 1,603 records · Page 89
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Modeling for the phased injector upgrade for 12 GeV CEBAF

The upcoming Jefferson Lab K-Long experiment at Hall D will require unique beam conditions with a much lower bunch repetition rate and atypically high bunch charge. To optimize the Continuous Electron Beam Accelerator Facility (CEBAF) injector for this experiment, we performed Multi-Objective Genetic Optimization (MGO) using General Particle Tracer (GPT) to determine the magnetic elements and RF settings necessary for the K-long bunch charge (0.64 pC) at 200 kV. We also investigated the transmission and beam characteristics of low to high charge per bunch electron beams through the injector for simultaneous operations of all four CEBAF Halls and characterized the transmission as a function of the photocathode laser spot size and pulse length. Our findings provide valuable insights into optimizing the CEBAF injector for the Jefferson Lab K-Long experiment, as well as for other experiments with similar beam conditions

Kazimi, R.↗
DOE OSTI2022

A Wide Dynamic-Range Halo Monitor for 8 GeV Proton Beams at FNAL

Eliminating harmful beam halos is the most important technique for high-intensity proton accelerators. Therefore, beam halo diagnosis is indispensable and becomes more and more important. At J-PARC, a wide dynamic range monitor was installed in the beam transport line in 2012. The device is a two-dimensional beam profile monitor [*, **], and it has a dynamic range of approximately six digits of magnitude by using Optical Transition Radiation and fluorescence screens. The FNAL accelerator complex has been upgrading through increased beam intensity and beam quality. A new beam halo diagnostic device is required in the beam transport line between the booster and recycler. It will be manufactured in a collaboration between J-PARC and FNAL as a part of the U.S.-Japan Science and Technology Cooperation Program in High Energy Physics. We are redesigning the monitor to satisfy FNAL specifications for beam energy, intensity, and size. The equipment will be manufactured at J-PARC and then shipped to FNAL in 2024. In this report, the design of the device will be described.

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

Transverse Single Spin Asymmetries of Heavy Flavor Electrons and Charged Pions in 200 GeV $p+p^{\uparrow}$ Collisions at Midrapidity

Transverse single spin asymmetries of particles produced in p+p^{\uparrow} p + p ↑ collisions provide insight on the partonic spin and momentum structure of hadrons; heavy flavor electrons provide access to initial state spin-momentum correlations of gluons in the proton, while charged pions provide access to initial and final state transverse spin effects. Charged particles are measured at midrapidity at PHENIX using the silicon vertex detector and central arm spectrometer, made of an electromagnetic calorimeter, a ring-imaging Cherenkov detector, and drift and pad chambers. Recent results for both electron and charged pion measurements from the 2015 running period will be presented.

Fitzgerald, Dillon↗
DOE OSTI2022

Measurement of Transverse Spin Dependent Azimuthal Correlations of Charged Pion(s) in $p^{\uparrow} p$ Collisions at $\sqrt s = 200$ GeV at STAR

At the leading twist, the transversity distribution function, h^{q}_{1}(x) h 1 q ( x ) , where x x is the longitudinal momentum fraction of the proton carried by quark q q , encodes the transverse spin structure of the nucleon. Extraction of it is difficult because of its chiral-odd nature. In transversely polarized proton-proton collisions ( p^\uparrow p p ↑ p ), h_{1}^{q}(x) h 1 q ( x ) can be coupled with another chiral-odd partner, a spin-dependent fragmentation function (FF). The resulting asymmetries in hadron(s) azimuthal correlations directly probe h_{1}^{q}(x) h 1 q ( x ) . We report the measurement of correlation asymmetries for charged pion(s) in p^\uparrow p p ↑ p , through the Collins and the Interference FF channel.

Pokhrel, Babu↗
DOE OSTI2012

Beam-beam effects with stochastic cooling in the 2012 RHIC 100 GeV heavy ion run

The 3-D stochastic cooling has been implemented in RHIC for the first time in the 2012 heavy ion run. In the U-U run, the U beam’s transverse emittances were cooled from initially about 13.5 mm.mrad down to 2.5 mm.mrad. The beam-beam parameters reached a maximum of -0.005. In the Cu-Au run, due to the unbalanced transverse beam sizes of the Cu and Au beams in the first several hours at the store, the Cu beam lifetime was significantly reduced by the beam-beam interaction. To maintain the Cu beam lifetime and to maximize the integrated luminosity, we intentionally reduced the cooling rate for the Au beam until the Cu beam got cooled. In this article, we review the beambeam effects in the 2012 RHIC heavy ion run and carry out numerical simulations to interpret the observations.

43 PARTICLE ACCELERATORS↗
DOE OSTI2012

Beam-Beam Effects with Stochastic Cooling in the 2012 RHIC 100 GEV Heavy Ion Run

The 3-D stochastic cooling has been implemented in RHIC for the first time in the 2012 heavy ion run. In the U-U run, the U beam’s transverse emittances were cooled from initially about 13.5 mm.mrad down to 2.5 mm.mrad. The beam-beam parameters reached a maximum of -0.005. In the Cu-Au run, due to the unbalanced transverse beam sizes of the Cu and Au beams in the first several hours at the store, the Cu beam lifetime was significantly reduced by the beam-beam interaction. To maintain the Cu beam life-time and to maximize the integrated luminosity, we intentionally reduced the cooling rate for the Au beam until the Cu beam got cooled. In this article, we review the beam-beam effects in the 2012 RHIC heavy ion run and carry out numerical simulations to interpret the observations.

43 PARTICLE ACCELERATORS↗
DOE OSTI2013

A Heavy Ion Fireball freeze-out Dipion Cocktail vs Angular Correlations for Au-Au Collisions at root $\sqrt{S_{NN}}$=200 GeV (Part 2)

The ultra-relativistic heavy ion collision starts out as a state of high density nuclear matter called the Quark Gluon Plasma(QGP) and expands rapidly to freeze-out. During the freeze out phase quarks and gluons form a system of strongly interacting hadrons. These hadrons continue to expand in a thermal manner until no further scattering is possible because the system becomes to dilute.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2012

Study of Low $p_{T}$ $D^{0}$ Meson Production at CDF II in $p\bar{p}$ Collisions at $\sqrt{s}$ = 900 GeV

In this thesis a study of the D 0 meson production in proton-antiproton collisions is presented. The data were collected with the CDF II detector at the Tevatron Collider of the Fermi National Accelerator Laboratory. This work is part of a specific effort by the CDF Collaboration to measure the inclusive differential cross section of prompt charmed mesons in the low pT kinematic region.

Gramellini, Elena↗
DOE OSTI2013

Parity Violating Deep Inelastic Electron Scattering from the Deuteron at 6 GeV

An experiment that measured the parity violating (PV) asymmetry A d in e- 2 H deep inelastic scattering (DIS) at Q 2 ~ 1.10 and 1.90 (GeV/c) 2 and x B ~ 0.3 was completed in experimental Hall A at the Thomas Jefferson National Accelerator Facility. The asymmetry can be used to extract the neutral weak coupling combination (2C 2u -C 2d ), providing a factor of five to six improvement over the current world data. To achieve this precision, asymmetries of the 10 -4 level needed to be measured at event rates up to 500 kHz with high electron detection efficiency and high pion background rejection capability. A specialized scaler-based counting data acquisition system (DAQ) with hardware-based particle identification was successfully implemented. The statistical quality of the asymmetry measurement agreed with the Gaussian distribution to over five orders of magnitudes and the experimental goal of 3-4% statistical uncertainty was achieved. The design and performance of the new DAQ system is presented with the preliminary asymmetry results given in the end.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

Full Simulation for the Qweak Experiment at 1.16 and 0.877 GeV and their Impact on Extracting the PV Asymmetry in the N → Δ Transition.

The Qweak project is seeking to find new physics beyond the Standard Model. It is aimed to measure the weak charge of the proton, which has never been measured, at 4% precision at low momentum transfer. The experiment is performed by scattering electrons from protons and exploiting parity violation in the weak interaction at low four-momentum transfer. In this experiment, two measurements were considered: which are elastic and inelastic. The elastic is to measure the proton's weak charge. In addition, the inelastic asymmetry measurement, which will extract the low energy constant d. That measurement works in the neutral current sector of the weak interaction. Qweak measures the asymmetry in the N → Δ; transition. Because the elastic radiative tail gives a dominant contribution to the uncertainty to the N → Δ; asymmetries, this thesis will discuss the radiative correction. In addition, this thesis will describe in details the extensive simulations preformed to determine the impact of all simulated background processes on extracting the PV N → Δ; asymmetries. In the process of verifying the validity of these background fractions, we determined the best value of a quantity measured during the Qweak experiment: the beam normal single spin asymmetry, Bn, in the N → Δ; transition.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2021

DUNE and MINERvA Flux Studies and a Measurement of the Charged-Current Quasielastic Antineutrino Scattering Cross Section with $<E_{\nu}> \sim 6 $ GeV on a CH Target

One of the biggest open questions in physics is the prevalence of matter over anti-matter in the present universe. One of possible answers lies in the violation of charge and parity symmetry in the lepton sector that would favor matter over anti-matter so that the universe becomes dominated by matter over time. Recent results from neutrino experiments like T2K and NOvA have indicated that there is CP violation in the leptonic sector \citep{Abe:2019vii}. However, the precise measurement of CP violation will require an unprecedented level of accuracy in these oscillation experiments. One of the challenges lies with the systematic uncertainties that come with the measurements, which include uncertainties related to the neutrino flux modeling, interaction modeling and detector related systematic uncertainties.\\ The first part of this thesis will go through the challenges related to flux uncertainties. It will discuss the flux uncertainties related to hadron production in the LBN F beamli ne for the DUNE experiment. Hadron production models used in flux simulations vary widely depending on the simulation and choice of physics models used to simulate the hadron production. This thesis will explain the method of using existing hadron production data to constrain these uncertainties, a method which has been used in MINERvA experiment.\\ The second part of the thesis goes through the effect of possible flux mismodeling and MINERvA's approach to address this effect. In doing so, we discovered that the suspected mismodeling could also result from incorrect estimation of the energy scale of the muons. This project not only demonstrated the challenges of flux modeling but also led to a novel approach of using neutrino energy spectra to understand the correlation between detector and neutrino beamline parameters. \\ A high statistics measurement of the anti-neutrino scattering cross section in the charged current quasielastic (CCQE) channel is the final part of the th esis. Th e 2-body interactions in this channel have the advantage of allowing reconstruction of the interaction kinematics from the outgoing muon trajectory which can be measured very well. Double differential cross sections as a function of muon kinematics, one of the deliverables of this analysis, will help future oscillation experiments understand their data. The cross-section as a function of the four-momentum transferred from the leptonic system to the hadronic system ($Q^{2}_{QE}$) can be used to test models used in simulating antineutrino interactions and the nuclear effects that can modify the predicted cross sections. Nuclear effects arise from the complex nuclear environment and both modify the initial scattering and change the fate of the particles produced from in neutrino-nucleus interactions. Study of nuclear effects will help to understand the structure of the atomic nucleus and its impact on neutrino interactions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗