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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 361 records · Page 20
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

FFA BEAM TRANSPORT DEMONSTRATION DEVELOPMENT FOR THE CEBAF 22 GeV UPGRADE

Jefferson Lab is planning an upgrade of the Continuous Electron Beam Accelerator Facility (CEBAF) to deliver highly polarized electron beams up to 22 GeV using Fixed- Field Alternating-gradient (FFA) magnets. As the application of FFA technology in the 10–22 GeV energy range is unprecedented, experimental validation is required prior to full-scale implementation. To support this effort, a dedicated FFA test insert is proposed within the existing CEBAF infrastructure, with candidate locations in the Beam Switchyard (BSY) dump line or the Hall C beamline. The testbed will consist of a half or full FFA cell using combined-function permanent magnets and will enable systematic studies of beam transport, field quality, alignment, and magnet performance under realistic conditions. Operation with polarized beams in the 5–11 GeV range will closely replicate the energy scaling of the full upgrade. This paper presents the current design status and layout options for the proposed FFA beam transport test line.

Ogur, S. [Thomas Jefferson National Accelerator Fa↗
DOE OSTI2026

Transport of 12 GeV positron beams at Ce+BAF

Jefferson Lab (JLab) is developing a concept to upgrade the Continuous Electron Beam Accelerator Facility (CEBAF) to additionally deliver spin-polarized continuous-wave positron beams for its nuclear physics program users (Ce+BAF 12 GeV). The concept involves repurposing the Low Energy Recirculator Facility (LERF) at JLab as a dual injector, first producing 100-300 MeV spin-polarized electron beams which are subsequently used for the generation and formation of 123 MeV continuous-wave positron beams. The positron beams are transported to CEBAF and injected for acceleration up to 12 GeV, tailored to the requirements of its four experimental halls. Given the higher emittance of the secondary positron beams, the CEBAF optics are optimized for low dispersion and low beta functions to enhance transmission within the Ce+BAF acceptance limits and with an R56 to manage the positron beams bunch length and energy spread. Potential bottlenecks are being investigated through both optical modeling and measurements using an electron beam, as well as degraded electron beams, to map the 6d acceptance of CEBAF as it is today. This presentation shares preliminary results from multi-particle tracking simulations of the positron beam up to 12 GeV, including spatial, momentum, and spin characteristics, and explores the feasibility of delivering beams simultaneously to multiple experimental halls via extraction optics.

Accelerator Physics↗
DOE OSTI2011

A Lattice for a Hybrid Fast-Ramping Muon Accelerator to 750 GeV

We describe a lattice for accelerating muons from 375 GeV to 750 GeV. The lattice is a fast-ramping synchrotron with a mixture of fixed-field superconducting dipoles and warm dipoles, so as to have a high average bending field while still being able to rapidly change the average bending field as the beam momentum increases. For a 1.5 TeV center of mass muon collider, muons must be rapidly accelerated to 750 GeV. To accomplish this efficiently, we wish to make as many passes through the RF cavities as possible, while keeping the average RF gradients sufficiently high to avoid excess muon decays. A synchrotron where the magnets are very rapidly ramped has been envisioned as one option to accomplish this. The entire acceleration cycle takes place in less than 1 ms, presenting a technological challenge for the magnets. Clearly superconducting magnets cannot be ramped on this time scale, so instead room-temperature magnets will be ramped. To keep losses low, dipoles can use grain-oriented silicon steel, but quadrupoles will probably need to use more conventional steel, giving a lower maximum field for these high ramping rates. If we want to have a large average RF gradient and simultaneously make a large number of passes through the RF cavities, the average bending field must be high. To achieve such a large bending field while rapidly ramping magnets, it has been proposed to use a hybrid lattice consisting of interleaved superconducting dipoles and bipolar ramped dipoles.

43 PARTICLE ACCELERATORS↗
DOE OSTI2013

Measurement of Muon Neutrino Quasielastic Scattering on a Hydrocarbon Target at $E_{\nu}$ $\sim$3.5 GeV

In this thesis, we present the measurement of the charged-current quasi-elastic interaction on polystyrene scintillator (CH) in the MINERA detector at neutrino energy between 1.5 GeV and 10.0 GeV ( 3:5 GeV). The data used was taken between March and July 2010, with a total of 9.421019 protons-on-target. Interactions were selected by requiring a negative muon and low calorimetric recoil energy separated from the interaction vertex. The analysis was performed on 29,620 charged current quasi-elastic interaction candidates in MINERA's ne-grained scintillator tracker region. The measurement is reported as a ux-averaged single dierential cross section in Q2 and compared with the prediction of dierent theoretical models in Monte Carlo simulations. Dierence in shape between the measured d=dQ2 QE and the expectation from a model based on independent nucleons in a relativistic fermi gas is found.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2019

Heavy Photon Displaced Vertex Search at 2.3GeV with Prospects for True Muonium Discovery

The Heavy Photon Search (HPS) collaboration at Jefferson Lab is searching for a new massive U(1) gauge boson known as the A', or dark photon, in the sub-GeV regime, which arises from considering an additional symmetry in the Standard Model. Though part of a hidden sector, the A' also kinetically mixes with the photon of electromagnetism, allowing it to have detectable QED decays. The signatures of this new particle in a fixed target experiment include a resonance in the e + e - invariant mass spectrum and a displaced vertex of its decay products, which the HPS detector in Hall B at JLab is equipped to detect. HPS is also sensitive to discover True Muonium (TM), an exotic bound state which has never been observed in experiment. In this dissertation, data taken from the 2016 HPS run at 2.3GeV beam energy is analyzed to search for a displaced decay vertex from an A'. The True Muonium yield is also estimated using Monte Carlo simulations, to determine the feasibility for a True Muonium search in future runs at 6.6GeV.

Yale, Bradley↗
DOE OSTI2023

Hunting Sub-GeV Dark Matter with Diamonds and Magnetic Microcalorimeters Principle

This project is to study feasibility of a new concept for the sub-GeV dark matter (DM) detection using diamond crystals and magnetic microcalorimeters (MMCs). Diamond crystals are made of low mass carbon constituent that maximize kinetic energy of nuclear recoils from sub-GeV DM scattering due to their relatively similar masses. MMC is employed as a sensitive phonon sensor to measure athermal phonons that are produced by DM scattering in diamond crystals with 100 ns timing resolution and ~10 eV energy resolution. MMC’s fast timing resolution allows high precision phonon pulse shape analysis to separate out unwanted background or noise signals in the low energy region at E < 1 keV. Especially, the low energy excess (LEE) problems have been reported in the dark matter detection community and the proposed diamond-MMC detector might be able to provide important information to understand the origins of LEE signals in DM detectors. In this project a diamond-MMC detector has been built for proof-of-concept experiments and athermal phonon collection efficiencies have been investigated for single crystal and poly-crystal chemical-vapour-diamonds (SC and PC CVDs) as well as reference sapphire crystals are tested in the same geometries to quatify athermal phonon propagation and their collection to the MMC phonon sensors. Athermal phonon collection efficiencies and their lifetime in the diamond and sapphire crystals are successfully measured in the same geometry and experimental setup for comparison. SC CVD crystals exhibit poorer performance than the sapphire reference crystals in athermal phonon collection, while the PC CVD crystal exhibit better result than the sapphire. PC CVD with MMC phonon sensors would be feasible for sub GeV DM detection.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2018

Physics reach at JLab with the 12 GeV upgrade

The Continuous Electron Beam Accelerator Facility (CEBAF) and associated experimental equipment at Jefferson Lab comprise a unique facility for nuclear physics research whose upgrade has been just completed. The upgraded facility accelerates electron beams to 11 GeV for experiments in the existing Halls A, B and C. In addition, a 12 GeV beam is provided to a new experimental Hall D to generate a 9 GeV tagged photon beam. This upgrade will quantitatively address the nature of confinement and an era of nuclear femtography through precision measurements of the spectrum and structure of hadrons comprised of light quarks and gluons. This facility also provides new opportunities relevant to neutrino oscillation physics, ``dark photon'' searches, and precision tests of the standard model.

Rossi, Patrizia↗
DOE OSTI2017

Overview of the Jefferson Lab 12 GeV Experimental Program in Halls A,B, and C

The 11 GeV beam energy available in experimental Halls A, B, and C as part of the Jefferson Lab 12 GeV Upgrade, combined with the new equipment in those halls will provide a rich and diverse physics program. This program includes inclusive measurements used to constrain polarized and unpolarized quark distributions in nucleons, exclusive reactions to access nucleon and meson form factors and GPDs, semi-inclusive measurements aimed at constraining TMDs, as well as measurements from nuclei to provide further insight into the origins of Short Range Correlations and the EMC Effect. The experimental equipment was designed with the above program in mind and the three halls provide complementary capabilities. Magnetic focusing spectrometers in Hall C (the new SHMS and existing HMS) will provide precision separated and unseparated cross section measurements and ratios. The new large acceptance CLAS12 spectrometer in Hall B enables measurements over broad regions of phase space. In Hall A, the new SBS spectrometer, used in conjunction with the existing HRS or Big Bite spectrometers will provide access to very large Q2 and allow for measurements requiring both high luminosity and large acceptance. This talk will give an overview of the upcoming experimental program in Halls A,B, and C, in particular highlighting synergies between the hall programs, which will allow Jefferson Lab to maximize the science output its 12 GeV program.

Gaskell, David↗
DOE OSTI2023

Lattice Design of the EIC Electron Storage Ring for Energies Down to 5 GeV

The Electron-Ion Collider (EIC) at Brookhaven National Laboratory will feature an electron storage ring that will circulate polarized beams with energies up to 18 GeV. Recently a study has been undertaken to extend the minimum energy from 6 GeV to 5 GeV. As the solenoid-based spin rotators around the interaction point require specific bending angles that depend on the energy range, this change results in major changes to the geometry. Moreover, avoiding interference of the electron beamline with the other beamlines in the tunnel, as well as with the tunnel walls, is a formidable challenge, especially at the location of the large-diameter superconducting solenoids. In this contribution, the details of the modified spin rotators, geometrical layout, and optics of the revised lattice are presented.

43 PARTICLE ACCELERATORS↗
DOE OSTI2023

22 GeV CEBAF with Novel Fixed Field Alternating Gradient Design

Extending the energy reach of CEBAF up to 22 GeV within the existing tunnel is being explored. Proposed energy upgrade can be achieved by increasing the number of recirculations, while using the existing CEBAF SRF cavity system. Presented scheme is based on an exciting new approach to acceleratie electrons efficiently with multiple passes in a single FFA beam line. Encouraged by recent success of the CBETA Test Accelerator, a proposal was formulated raise CEBAF energy by replacing the highest-energy arcs with Fixed Field Alternating Gradient (FFA) arcs. The new pair of arcs configured with FFA lattice would support simultaneous transport of additional 6 passes with energies spanning a factor of two, using the non-scaling FFA principle implemented with Halbach-derived permanent magnets - a novel magnet technology that significantly saves energy and lowers operating costs. One of the challenges of the multi-pass (11) linac optics is to provide uniform focusing in a vast range of energies, using fixed field lattice. Here, we propose a triplet lattice scaled up with increasing momentum along the linac. This would provide a stable periodic solution covering energy ratio of 1:33. The current CEBAF configured with a 123 MeV injector, makes optical matching in the first linac virtually impossible due to extremely high energy span ratio (1:175). Therefore, we envision replacement of the current injector with a 650 MeV 3-pass recirculating injector based on the existing LERF facility. Finally, the 22 GeV CEBAF would promise to deliver in 10-passes a beam with normalized emittance of 80 mm·mrad and with a relative energy spread of 1.5 × 10-3. Further recirculation beyond 22 GeV is limited by large, 974 MeV per electron, energy loss due to synchrotron radiation.

Bogacz, Slawomir↗
DOE OSTI2017

35 GeV e-p collisions, SM type, LEPTO/ARIADNE generator: gev35ep_lepto6ard_dis1q2

Electron-proton collisions. LEPTO 6.5 with ARIADNE 4.12. Q2>1 GeV2. MSTW2008lo68cl PDF (LHAPDF= 21000). Other default parameters are E(scattered)>1 GeV and W2>5 GeV2. Collision energy: E(p)=60 GeV and E(e-)=5 GeV. These energies are designed for the JLab EIC proposal. The samples were requested by J.Repond for ANL LDRD studies.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

35 GeV e-p collisions, SM type, LEPTO/PYTHIA generator: gev35ep_lepto6_dis1q2

Electron-proton collisions. LEPTO 6.5 with PYTHIA 5.7 for PS and hadronization. Q2>1 GeV2. CT10W PDF (LHAPDF= 10900). Other default parameters are E(scattered)>1 GeV and W2>5 GeV2. Collision energy: E(p)=60 GeV and E(e-)=5 GeV. These energies are designed for the JLab EIC proposal. The samples were requested by J.Repond for ANL LDRD studies.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

35 GeV e-p collisions, SM type, LEPTO/ARIADNE generator: gev35ep_lepto6ard_dislowq2

Electron-proton collisions. LEPTO 6.5 with ARIADNE 4.12. Q2>1 GeV2. Min W2 was set to 4 GeV2, and the minimum energy of scattered electron was set to 0.3 GeV. MSTW2008lo68cl PDF (LHAPDF= 21000) is used. Collision energy: E(p)=60 GeV and E(e-)=5 GeV. These energies are designed for the JLab EIC proposal. The samples were requested by J.Repond for ANL LDRD detector studies. Note that all exclusive processes were removed, therefore, this sample is not realistic for physics.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

35 GeV e-p collisions, SM type, LEPTO/ARIADNE generator: gev35ep_lepto6ard_dislowq2_jlab

This is a test sample to check the availability of Jlab data server. This sample is identical to gev35ep_lepto6ard_dislowq2. Electron-proton collisions. LEPTO 6.5 with ARIADNE 4.12. Q2>1 GeV2. Min W2 was set to 4 GeV2, and the minimum energy of scattered electron was set to 0.3 GeV. MSTW2008lo68cl PDF (LHAPDF= 21000) is used. Collision energy: E(p)=60 GeV and E(e-)=5 GeV. These energies are designed for the JLab EIC proposal. The samples were requested by J.Repond for ANL LDRD detector studies. Note that all exclusive processes were removed, therefore, this sample is not realistic for physics.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

45 GeV e-p collisions, SM type, PCSIM generator: gev45ep_pcsim_upsilon

Upsilon(1S) production to e+e-. Collision energy: E(p)=100 GeV and E(e-)=5 GeV. CM energy is 44.7 GeV. There samples are designed for detector studies, and are not be expected to be realistic in terms of the cross sections. The cross section includes the original cross section times the branching ratio Upsilon(1S) to electrons.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

45 GeV e-p collisions, SM type, PCSIM generator: gev45ep_pcsim_jpsi

J/Psi production to e+e-. Collision energy: E(p)=100 GeV and E(e-)=5 GeV. CM energy is 44.7 GeV. The cross section includes the original cross section times the branching ratio J/Psi to electrons. There samples are designed for detector studies, and are not be expected to be realistic in terms of the cross sections.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

Time stretching of the GeV emission of GRBs: Fermi-LAT data versus geometrical model

It is known that the high-energy (>100 MeV) emission of gamma-ray bursts is delayed with respect to the low-energy emission. However, the dependence of light curves on energy has not been studied for the high-energy bands. In this paper, we consider the bursts observed by Fermi LAT from 2008 August 4 to 2011 August 1, for which at least 10 photons were observed with energy greater than 1 GeV. These include four bursts: GRB 080916C, GRB 090510, GRB 090902B, and GRB 090926A. We use the Kolmogorov–Smirnov test to compare the light curves in the two bands 100 MeV 1 GeV. For GRB 080916C and GRB 090510 the light curves in the two bands are statistically compatible. However, for GRB 090926A, the higher-energy light curve is stretched compared to the lower-energy one with a statistical significance of 3.3σ and, for GRB 090902B, on the contrary, the lower-energy curve is stretched with 2.3σ significance. We argue that the observed diversity of stretching factors may be explained using a simple geometrical model. The model assumes that the jet opening angle depends on the emission energy in a way that the most energetic photons are radiated near the axis of the jet. All of the bursts are considered equivalent in their rest frames, and the observed light curves differ only due to different redshifts and view directions. The model conforms to the total burst energy constraint and matches the Fermi-LAT observations of the fraction of GRBs visible in the 100 MeV<E<1 GeV band, which may be observed at higher energies. The model predicts the distribution of observable stretching factors, which may be tested in future data. Finally, we propose a method to estimate the observer's off-axis angle based on the stretching factor and the fraction of the high-energy photons. The code for modeling is open source and is publicly available on GitHub (https://github.com/maxitg/GammaRays).

79 ASTRONOMY AND ASTROPHYSICS↗