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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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS1984

Means and method for calibrating a photon detector utilizing electron-photon coincidence

An arrangement for calibrating a photon detector particularly applicable for the ultraviolet and vacuum ultraviolet regions is based on electron photon coincidence utilizing crossed electron beam atom beam collisions. Atoms are excited by electrons which lose a known amount of energy and scatter with a known remaining energy, while the excited atoms emit photons of known radiation. Electrons of the known remaining energy are separated from other electrons and are counted. Photons emitted in a direction related to the particular direction of scattered electrons are detected to serve as a standard. Each of the electrons is used to initiate the measurements of a time interval which terminates with the arrival of a photon exciting the photon detector. Only the number of time intervals related to the coincidence correlation and of electrons scattered in the particular direction with the known remaining energy and photons of a particular radiation level emitted due to the collisions of such scattered electrons are counted. The detector calibration is related to the number of counted electrons and photons.

Srivastava, S. K.↗
NASA NTRS1972

Production cross sections for Lee-Wick massive electromagnetic bosons and for spin-zero and spin-one W bosons at high energies.

Production cross sections for three types of hypothetical particles are calculated in the presented paper. Several (Z, Z') cases were studied corresponding to elastic scattering off protons and neutrons (either free or embedded within a Fermi sea), coherent scattering off a nucleus, and inelastic scattering off a proton (in which case Z' denotes a nucleon resonance or hadronic system in the continuum). Detailed structure-function data are used to improve the accuracy of the inelastic scattering calculation. Results of calculations are given for beam energies between 50 and 10,000 GeV, and masses between 5 and 40 GeV for the massive Lee-Wick spin-1 boson. Cross sections were computed for resonant and semiweak processes. The production cross section of spin-zero weak intermediate bosons was found to be at least one order of magnitude smaller than for spin-1 weak bosons in nearly all regions of interest. The production cross section of spin-zero weak intermediate bosons for inelastic scattering off protons compares with that for elastic scattering in the regions of interest. In the case of massive spin-1 bosons and spin-1 weak intermediates, the main contribution to total production cross section off protons is elastic.

Linsker, R.↗
DOE OSTI2022

Measurement of the Deeply Virtual Compton Scattering Cross Section from the Proton at 10.6 GeV using the CLAS12 Detector

Deeply Virtual Compton Scattering (DVCS) is an exclusive process that produces a real photon when a lepton scatters from a quark inside a nucleon or a nucleus. Measurement of the DVCS cross section enables the study of the Generalized Parton Distributions (GPD), which plays a central role in understanding the QCD dynamics inside a hadron. Thus, the quark and gluon origin of the nucleon spin and mass can be probed and three-dimensional images of the target nucleon or nucleus can be realized. This thesis presents a cross section analysis of DVCS from the proton in the presence of its background, Bethe-Heitler (BH) process. The CEBAF Large Acceptance Spectrometer for operation at 12 GeV beam energy (CLAS12) collaboration has taken electron-proton scattering data in fall 2018 using a liquid hydrogen target and the 10.6 GeV polarized electron beam from the Continuous Electron Beam Accelerator Facility (CEBAF). The CLAS12 detector is a nearly hermetic fixed-target detector, located in Hall B, Jefferson Lab at Newport News, Virginia. The experimentally determined BH-DVCS cross section is in good agreement with a phenomenological-model based theoretical prediction. The kinematic dependence of the cross section is reported over a wide range. The short-term plan to utilize the results presented here for a thorough tomography study and the long-term plan for GPD studies at future facilities such as the Electron-Ion Collider (EIC) are discussed.

Lee, Sangbaek↗
NASA NTRS1997

Raman Spectroscopy for Mineral Identification and Quantification for in situ Planetary Surface Analysis: A Point Count Method

Quantification of mineral proportions in rocks and soils by Raman spectroscopy on a planetary surface is best done by taking many narrow-beam spectra from different locations on the rock or soil, with each spectrum yielding peaks from only one or two minerals. The proportion of each mineral in the rock or soil can then be determined from the fraction of the spectra that contain its peaks, in analogy with the standard petrographic technique of point counting. The method can also be used for nondestructive laboratory characterization of rock samples. Although Raman peaks for different minerals seldom overlap each other, it is impractical to obtain proportions of constituent minerals by Raman spectroscopy through analysis of peak intensities in a spectrum obtained by broad-beam sensing of a representative area of the target material. That is because the Raman signal strength produced by a mineral in a rock or soil is not related in a simple way through the Raman scattering cross section of that mineral to its proportion in the rock, and the signal-to-noise ratio of a Raman spectrum is poor when a sample is stimulated by a low-power laser beam of broad diameter. Results obtained by the Raman point-count method are demonstrated for a lunar thin section (14161,7062) and a rock fragment (15273,7039). Major minerals (plagioclase and pyroxene), minor minerals (cristobalite and K-feldspar), and accessory minerals (whitlockite, apatite, and baddeleyite) were easily identified. Identification of the rock types, KREEP basalt or melt rock, from the 100-location spectra was straightforward.

Haskin, Larry A.↗
DOE OSTI2023

Cross-beam energy transfer in conditions relevant to direct-drive implosions on OMEGA

In cross-beam energy transfer (CBET), the interference of two laser beams ponderomotively drives an ion-acoustic wave that coherently scatters light from one beam into the other. This redirection of laser beam energy can severely inhibit the performance of direct-drive inertial confinement fusion (ICF) implosions. To assess the role of nonlinear and kinetic processes in direct-drive-relevant CBET, the energy transfer between two laser beams in the plasma conditions of an ICF implosion at the OMEGA laser facility was modeled using particle-in-cell simulations. For typical laser beam intensities, the simulations are in excellent agreement with linear kinetic theory, indicating that nonlinear processes do not play a role in direct-drive implosions. At higher intensities, CBET can be modified by pump depletion, backward stimulated Raman scattering, or ion trapping, depending on the plasma density.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2022

Neutrino interaction measurements with the MicroBooNE and ArgoNeuT liquid argon time projection chambers

Abstract Precise modeling of neutrino interactions on argon is crucial for the success of future experiments such as the Deep Underground Neutrino Experiment (DUNE) and the Short-Baseline Neutrino (SBN) program, which will use liquid argon time projection chamber (LArTPC) technology. Argon is a large nucleus, and nuclear effects—both on the initial and final-state particles in the interaction—are expected to be large in neutrino–argon interactions. Therefore, measurements of neutrino scattering cross sections on argon will be of particular importance to future DUNE and SBN oscillation measurements. This article presents a review of neutrino–argon interaction measurements from the MicroBooNE and ArgoNeuT collaborations, using two LArTPC detectors that have collected data in the NuMI and Booster Neutrino Beams at Fermilab. Measurements are presented of charged-current muon neutrino scattering in the inclusive channel, the ‘0 $$\pi $$ π ’ channel (in which no pions but some number of protons may be produced), and single pion production (including production of both charged and neutral pions). Measurements of electron neutrino scattering are presented in the form of $$\nu _e+\bar{\nu }_e$$ ν e + ν ¯ e inclusive scattering cross sections.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2025

Pump with Broadband Probe Experiments for Single-Shot Measurements of Plasma Conditions and Crossed-Beam Energy Transfer

Here, a novel technique for measuring plasma conditions using monochromatic pump-broadband-probe laser interactions has been experimentally demonstrated. Originally proposed in Ludwig et al. [Phys. Plasmas 26, 113108 (2019)], this method utilizes crossed-beam energy transfer between the broadband probe and the pump, mediated by plasma ion acoustic waves. The complete energy transfer spectrum can be captured in a single shot, enabling the inference of plasma parameters such as density, electron and ion temperatures, and flow velocity. Compared to Thomson scattering, this technique offers signal enhancements typically larger than 9 orders of magnitude, significantly reducing the required probe laser intensity and facilitating interactions that are linear and measurements that are nonperturbative of the plasma. Furthermore, it provides a powerful tool for advancing studies of crossed-beam energy transfer under conditions relevant to inertial confinement fusion experiments.

Physics - Plasma physics↗
DOE OSTI2022

Neutron-upscattering enhancement of the triple-alpha process

Abstract The neutron inelastic scattering of carbon-12, populating the Hoyle state, is a reaction of interest for the triple-alpha process. The inverse process (neutron upscattering) can enhance the Hoyle state’s decay rate to the bound states of 12 C, effectively increasing the overall triple-alpha reaction rate. The cross section of this reaction is impossible to measure experimentally but has been determined here at astrophysically-relevant energies using detailed balance. Using a highly-collimated monoenergetic beam, here we measure neutrons incident on the Texas Active Target Time Projection Chamber (TexAT TPC) filled with CO 2 gas, we measure the 3 α -particles (arising from the decay of the Hoyle state following inelastic scattering) and a cross section is extracted. Here we show the neutron-upscattering enhancement is observed to be much smaller than previously expected. The importance of the neutron-upscattering enhancement may therefore not be significant aside from in very particular astrophysical sites (e.g. neutron star mergers).

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2020

Transverse-energy-energy correlations in deep inelastic scattering

Event shape observables have been widely used for precision QCD studies at various lepton and hadron colliders. We present the most accurate calculation of the transverse-energy-energy correlation event shape variable in deep-inelastic scattering. In the framework of soft-collinear effective theory the cross section is factorized as the convolution of the hard function, beam function, jet function and soft function in the back-to-back limit. A close connection to TMD factorization is established, as the beam function when combined with part of the soft function is identical to the conventional TMD parton distribution function, and the jet function is the second moment of the TMD fragmentation function matching coefficient. We validate our framework by comparing the obtained LO and NLO leading singular distributions to the full QCD calculations in the back-to-back limit. We report the resummed transverse-energy-energy correlation distributions up to N 3 LL accuracy matched with the NLO cross section for the production of a lepton and two jets. Our work provides a new way to precisely study TMD physics at the future Electron-Ion Collider.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2021

Cross-Beam Energy Transfer Saturation by Ion Heating

Cross-beam energy transfer (CBET) saturation by ion heating was measured in a gas-jet plasma characterized using Thomson scattering. Here, a wavelength-tunable ultraviolet (UV) probe laser beam was interacted with four intense UV pump beams to drive large-amplitude ion-acoustic waves. For the highest-intensity interactions, the power transferred to the probe laser dropped, demonstrating ion-acoustic wave saturation. Over this time, the ion temperature was measured to increase by a factor of 7 during the 500-ps interaction. Particle-in-cell simulations show ion trapping and a subsequent ion heating consistent with measurements. Linear kinetic CBET models were found to agree well with the observed energy transfer when the measured plasma conditions were used.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
NASA NTRS1975

Theoretical and experimental studies in ultraviolet solar physics

The processes and parameters in atomic and molecular physics that are relevant to solar physics are investigated. The areas covered include: (1) measurement of atomic and molecular parameters that contribute to discrete and continous sources of opacity and abundance determinations in the sun; (2) line broadening and scattering phenomena; and (3) development of an ion beam spectroscopic source which is used for the measurement of electron excitation cross sections of transition region and coronal ions.

Parkinson, W. H.↗
NASA NTRS2007

Focal-Plane Imaging of Crossed Beams in Nonlinear Optics Experiments

An application of focal-plane imaging that can be used as a real time diagnostic of beam crossing in various optical techniques is reported. We discuss two specific versions and demonstrate the capability of maximizing system performance with an example in a combined dual-pump coherent anti-Stokes Raman scattering interferometric Rayleigh scattering experiment (CARS-IRS). We find that this imaging diagnostic significantly reduces beam alignment time and loss of CARS-IRS signals due to inadvertent misalignments.

Bivolaru, Daniel↗
NASA NTRS1990

Ionisation of atomic hydrogen by positron impact

With the crossed beam apparatus the relative impact-ionization cross section of atomic hydrogen by positron impact was measured. A layout of the scattering region is given. The first measurements on the ionization of atomic hydrogen by positron impact are also given.

Spicher, Gottfried↗
DOE OSTI2020

First Measurement of Differential Charged Current Quasielasticlike $\nu_{\mu}$ -Argon Scattering Cross Sections with the MicroBooNE Detector

We report on the first measurement of flux-integrated single differential cross sections for charged-current (CC) muon neutrino ($\nu_{\mu}$) scattering on argon with a muon and a proton in the final state, 40 Ar $(\nu_{\mu},μp)X$. The measurement was carried out using the Booster Neutrino Beam at Fermi National Accelerator Laboratory and the MicroBooNE liquid argon time projection chamber detector with an exposure of 4.59 × 10 19 protons on target. Events are selected to enhance the contribution of CC quasielastic (CCQE) interactions. The data are reported in terms of a total cross section as well as single differential cross sections in final state muon and proton kinematics. We measure the integrated per-nucleus CCQE-like cross section (i.e., for interactions leading to a muon, one proton, and no pions above detection threshold) of (4.93 ± 0.76 stat ± 1.29 sys )×10 -38 cm 2 , in good agreement with theoretical calculations. The single differential cross sections are also in overall good agreement with theoretical predictions, except at very forward muon scattering angles that correspond to low-momentum-transfer events.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

BEAM DYNAMICS CHALLENGES IN THE DESIGN OF THE ELECTRON-ION COLLIDER

The Electron-Ion Collider (EIC), presently under construction at Brookhaven National Laboratory, will collide polarized high-energy electron beams with hadron beams, achieving luminosities up to 1 × 1034 cm¿2 s¿1 in the center-of-mass energy range of 20-140 GeV. To achieve such high luminosity, we adopt high bunch intensities for both beams, small and flat transverse beam sizes at the interaction point (IP), a large crossing angle of 25 mrad, and a novel strong hadron cooling in the Hadron Storage Ring (HSR) to counteract intra-beam scattering (IBS) at the collision energy. In this talk, we will review the beam dynamics challenges in the design of the EIC, particularly the single-particle dynamic aperture, polarization maintenance, beam-beam interaction, impedance budget and instabilities. We will also briefly mention some technical challenges associated with beam dynamics, such as strong hadron cooling, multipoles and noises of crab cavities, power supply current ripples, and the vacuum upgrade to existing beam pipes of the Hadron Storage Ring of the EIC.

Luo, Y.↗
DOE OSTI2021

An experimental program with high duty-cycle polarized and unpolarized positron beams at Jefferson Lab

Positron beams, both polarized and unpolarized, are identified as important ingredients for the experimental programs at the next generation of lepton accelerators. In the context of the hadronic physics program at Jefferson Lab (JLab), positron beams are complementary, even essential, tools for a precise understanding of the electromagnetic structure of nucleons and nuclei, in both the elastic and deep-inelastic regimes. For instance, elastic scattering of polarized and unpolarized electrons and positrons from the nucleon enables a model independent determination of its electromagnetic form factors. Also, the deeply-virtual scattering of polarized and unpolarized electrons and positrons allows unambiguous separation of the different contributions to the cross section of the lepto-production of photons and of lepton-pairs, enabling an accurate determination of the nucleons and nuclei generalized parton distributions, and providing an access to the gravitational form factors of the energy-momentum tensor. Furthermore, positron beams offer the possibility of alternative tests of the Standard Model of particle physics through the search of a dark photon, the precise measurement of electroweak couplings, and the investigation of charged lepton flavor violation. This document discusses the perspectives of an experimental program with high duty-cycle positron beams at JLab.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2025

C 12 ( n , n 1 ′ γ ) partial γ -ray cross section measured using the GENESIS array

Improved neutron inelastic scattering cross sections have repeatedly been identified as a top priority nuclear data need, important for basic science and a range of applications in nuclear energy, stockpile stewardship, and proliferation detection. For the C 12 ( n , n ′ γ ) reaction in particular, recent measurements have unveiled some structural discrepancies, demonstrating incongruities among themselves and in relation to the ENDF/B-VIII.0 nuclear data evaluation. To help resolve these disagreements, a measurement was performed at the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory using a broad-spectrum neutron beam and a 99.8% pure natural carbon target. The Gamma Energy Neutron Energy Spectrometer for Inelastic Scattering (GENESIS) was employed to measure energy-differential γ -ray emission spectra as a function of incident neutron energy in the energy range of 5.5 to 16.7 MeV. The C 12 partial γ -ray cross sections were extracted at 63 ∘ , 122 . 5 ∘ , and 150 ∘ with respect to the incoming neutron beam and integrated using angular distribution data available in the literature. The data show agreement with a recent literature measurement and evaluation from 11 to 15 MeV, but indicate a larger cross section for incident neutron energies between 5.5 and 8.5 MeV. The measured relative angular distributions are also reported and were found to agree with evaluation. Published by the American Physical Society 2025

Gordon, J. M. (ORCID:0009000789886897)↗
DOE OSTI2020

Cross section of neutrons from the H 2 ( n , 2 n ) reaction at E n = 15 MeV

In this work, the double-differential cross section of the deuteron breakup reaction 2 H(n, 2n) has been studied experimentally with a neutron beam energy of 15 MeV. Special attention has been devoted to estimation of background condition and multiple scattering effect in the scattering sample. Experimental data have been compared with models based on phase-space approximation used in the ENDF/B-VIII.0 data library and in the MCNP neutron transport code, as well as with rigorous model based on Faddeev equations used for cross section evaluations in JENDL data library. It was found that experimental data are better reproduced by Faddeev model, however, the model overestimates data in the low-energy region of the neutron spectrum (<4 MeV)

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗