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At least 685 records · Page 38
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Thresholds for the Break of Nucleon Cooper Pairs and Special Features of the Decay of the {sup 172}Yb Nucleus in the Reaction {sup 171}Yb(n{sub th},2γ)

The reaction {sup 171}Yb(n{sub th},2γ) was studied with the aim of extending the experimental database of intensities of cascades of two photons emitted sequentially after radiative thermal-neutron capture. An analysis of these cascade intensities permitted revealing the change in the structure of observed levels of the {sup 172}Yb nucleus versus the excitation energy and determining probable thresholds for the break of four Cooper pairs of neutrons below the neutron binding energy.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2018

Elastic Deuteron Scattering on the {sup 12}C Nucleus within a Three-Body Model

The formalism developed earlier for elastic pd scattering on the basis of Glauber theory with allowance for a total spin dependence is modified by replacing pN amplitudes by amplitudes for N{sup 12}C scattering and is applied to elastic deuteron scattering on the {sup 12}C nucleus. The amplitudes for elastic N{sup 12}C scattering are obtained within the optical model. Respective numerical calculations performed at the kinetic deuteron-beam energy of 270 MeV lead to results that agree well with data on the differential cross section for d{sup 12}C scattering into the forward hemisphere, but the calculated spin observable A{sub y}{sup d} agrees with experimental data only qualitatively.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2022

Gluon saturation in proton and its contribution to single inclusive soft gluon production in high energy proton-nucleus collisions

The leading order single inclusive soft gluon production in high energy proton-nucleus (pA) collisions has been studied by various approaches for more than two decades. The first correction due to the gluon saturation in proton was analytically attempted recently through a diagrammatic approach in which only partial results were obtained. An important feature of the first saturation correction is that it includes both initial state and final state interactions. In this paper, we present the complete result derived from the Color Glass Condensate framework. Our approach is to analytically solve the classical Yang-Mills equations in the dilute-dense regime and then use the Lehmann-Symanzik-Zimmermann (LSZ) reduction formula to obtain gluon production from classical gluon fields.

Li, Ming↗
DOE OSTI2013

THE FREE GAS THERMAL TREATMENT IN MCATK: Sampling the Thermal Motion of the Target Nucleus (U)

The free gas thermal treatment for neutron scattering, as formulated for Monte Carlo by Coveyou et al., is implemented and tested in the MCATK software library. This treatment is necessary for two reasons: 1) to handle the kinematics of a neutron colliding with a target nucleus in thermal motion and 2) to accurately use ACE scattering data.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2012

Mobile Ice Nucleus Spectrometer

This first year report presents results from a computational fluid dynamics (CFD) study to assess the flow and temperature profiles within the mobile ice nucleus spectrometer.

Kulkarni, Gourihar R.↗
DOE OSTI2014

Development of a Mobile Ice Nucleus Counter

An ice nucleus counter has been constructed. The instrument uses built-in refrigeration systems for wall cooling. A cascade refrigeration system will allow the cold wall to operate as low as -70°C, and a single stage system can operate the warm wall at -45C. A unique optical particle counter has been constructed using polarization detection of the scattered light. This allows differentiation of the particles exiting the chamber to determine if they are ice or liquid.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2013

Coherent Elastic Neutrino Nucleus Scattering

Coherent Elastic Neutrino Nucleus Scattering (CENNS) has yet to be observed since its first prediction in 1974. The CENNS cross-section is precisely known in the Standard Model (SM). It is considerably larger than the other neutrino interaction channels at MeV energies. If measured at its predicted value, CENNS can be a very powerful tool for future neutrino oscillation experiments. Alternatively, any deviation from the very robust SM prediction could be a window to beyond-SM physics. The discovery of CENNS requires an intense source of low energy neutrinos, and a large-scale low energy threshold detector, both of which complement and build on existing programs at Fermilab. The Booster Neutrino Beamline (BNB) at Fermilab is a surprisingly powerful source of pion decay-at-rest ($\pi$DAR) neutrinos. The energy spectrum and flux of neutrinos in the backward direction (far-off-axis) of the BNB is excellent for a CENNS discovery measurement. At the closest practical location, the $\pi$DAR neutrino flux at BNB would be about a fifth of the neutrino flux of Spallation Neutron Source (SNS at Oak Ridge). The BNB site is preferable in almost every other aspect, however. First, the beam duty factor of BNB (2.5x10 -5 ) is about a factor of four better, which will help to reduce ambient backgrounds. Second, the potential experiment site, close to the BNB target, allows optimal placement of the detectors, with minimal sitting issues. The CENNS experiment would be completely parasitic to any running of the BNB. It would require no changes to the beamline, and place no additional requirements on the running mode or times. The $\pi$DAR neutrinos from the BNB are a by-product of running the beamline for MicroBooNE, and will be available for the foreseeable future. The CENNS detector would be a ton-scale single-phase Liquid Argon (LAr) detector, placed inside a water shield with an active cosmic ray veto. The low energy threshold and low background detector technology is already well developed thanks to work over the last decade in Dark Matter detector physics. Moreover, Fermilab is equipped with very strong technical and engineering resources in liquid argon detector development. One issue that must be addressed prior to the development of a full CENNS proposal is the question of whether the beam-related fast neutron background is low enough that it can be practically shielded.

Brice, S. J.↗
DOE OSTI2015

Neutrino-Nucleus Interactions and the Short-Range Structure of Nuclei

Improvements in theoretical modeling of Short Range structures and phenomena, and comparisons with data, will require sustained collaboration between nuclear theorists and neutrino experimentalists. The extensive history of studying this area of nuclear physics in electron- and hadron-scattering experiments, coupled with the transformative capabilities of LArTPCs to identify neutrinos, will provide a ripe opportunity for new discoveries that will further our understanding of the nucleus.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2019

Compact Cloud Condensation Nucleus Counter for Unmanned Aerial Systems (UAS) and Long-Term Monitoring Applications (Final Report)

Brechtel Manufacturing Incorporated (BMI) is developing a compact, modular suite of new aerosol measurement technologies optimized for use on Unmanned Aerial Vehicles (UAVs) and other applications where space, weight, power and cost are significant barriers to deployment. The project is focused on a cloud condensation nucleus counter that exposes sampled particles to a simulated cloud environment and counts how many of the particles grow to micron-sized droplets. The new development helps address the need for reduced uncertainties in climate model sensitivities to ambient aerosol properties by promoting the capability to perform aerosol measurements more often, in more locations, and at reduced cost. Applications of the new technology include long-term measurements of the aerosol effects on cloud radiation, microphysical and precipitation processes, weather prediction and modelling studies, and weather modification studies.

47 OTHER INSTRUMENTATION↗
DOE OSTI2021

Boson Fermion Nucleus Polynuclear Structure: Monograph #11

The boson fermion nucleus (BFN) structure indicates the possibility of stable, nonradioactive polynuclear structures bound by the strong nuclear force. In the process of making polynuclear structures, BFN self-ordering on the nuclear level as a stable structure resembles the self-ordering of carbon atoms at the atomic level into buckminsterfullerene, graphene sheet, or graphene nanotubes. This natural assembly derives from the modulation of electron orbital collapse, which decreases coulomb repulsion between atoms and allows a natural reordering among nuclear structures by modulating the permeability of free space. Polynuclear material would be unearthly in tensile strength, thermal and electrical conductivity, and heat of disassociation.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2022

Experimental Searches for Muon to Electron Conversion in a Nucleus: COMET, DeeMe, and Mu2e (A Contributed paper for Snowmass 21)

Searches for charged lepton flavor violation (CLFV) offer deep probes for a range of new physics scenarios, such as super-symmetric models, theories involving scalar leptoquarks or additional Higgs doublets, and models explaining the neutrino mass hierarchy and the matter-antimatter asymmetry of the universe via leptogenesis. The coherent, neutrinoless conversion of a muon to an electron in the field of a nucleus, $\mu^{-}+N\rightarrow e^{-} +N$, is one example of a muonic CLFV process which has sensitivity to this new physics. This paper details three experiments: COMET, DeeMe and Mu2e which will search for $\mu^{-}+N\rightarrow e^{-} +N$ in the coming decade. These experiments offer sensitivity up to an effective new physics mass scale of $\mathcal{O}(10^{4}$ TeV/c$^{2}$), going far beyond what can be achieved in direct, collider-based, searches. The theoretical motivation, designs and anticipated timelines for these three experiments are presented. These experiments are a crucial part of a global search for CLFV. Continued support for all planned experimental searches for muonic CLFV is strongly encouraged.

43 PARTICLE ACCELERATORS↗
DOE OSTI2023

Coherent Neutrino-Nucleus Scattering: A Tool to Search for New Physics

The Neutrino is a well-understood particle in the models of particle physics. Even so, it is electrically neutral, and has a very small mass. As such, it’s interaction probability is extremely small. Detecting neutrinos has always been a challenge for particle physics. Over 40 years ago, Daniel Freedman predicted a new type of interaction that neutrinos could undergo that would be much more frequent. This has since been called Coherent Elastic Neutrino Nucleus Scattering (CEvNS). While this process occurred more frequently than the traditionally used interaction process (called inverse beta decay) it was more challenging to detect. Interestingly, though, if you could detect the CEvNS process, you would be sensitive to many new studies of fundamental particle physics. A researcher may also be able to use this process to study neutrinos in more applied settings, for instance by more easily monitoring the neutrinos given off during the nuclear reaction processes in nuclear reactors. The aim of this project was to observe coherent neutrino scattering for the first time, and begin to use it as a tool both to study new types of physics models, and to study the feasibility of this concept for applied situations.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2014

High Momentum Nucleons in the Nucleus

Mean field models have traditionally been used to describe the behavior nucleons in the nucleus. However, differences in nucleon behavior in experiments ranging from valence knock-out reactions to high-energy deep-inelastic scattering experiments provide evidence that the properties of the bound nucleons are not identical to free nucleons. I will discuss the recent Jefferson Lab experiments that have sought to find the signatures of nucleon modifications by isolating high-momentum initial states, and also present the links this research has to other fields of nuclear physics such as neutrino scattering and deep inelastic scattering from heavy nuclei.

Higinbotham, Douglas↗
DOE OSTI2024

Structure of the high-spin, β-decaying state in the neutron-rich nucleus 146 La

Excited structures in 146 Ce were populated in β decay of the high-spin state in the neutronrich nucleus 146 La. The beam was produced by the Californium Rare Isotope Breeder Upgrade (CARIBU) facility at Argonne National Laboratory, re-accelerated by the ATLAS accelerator and implanted on a moving-tape system in the middle of the GAMMASPHERE array. The decay scheme of the high-spin, β-decaying state in 146 La was revised with respect to previous studies and evaluated nuclear data. The structure of 146 La is discussed in the framework of the deformed Nilsson model and systematics of known quasiparticle structures in the region.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2025

Neutrino-Nucleus Interactions in the Precision Era

Current and future accelerator-based neutrino facilities, leveraging intense neutrino beams and advanced detectors, aim to precisely determine neutrino properties and probe signals of weakly interacting beyond the Standard Model physics. Achieving discovery-level precision and fully exploring the physics potential of these experiments critically depends on the accuracy of our understanding of fundamental underlying neutrino-nucleus interaction processes. This talk will focus on neutrino interactions spanning energies from tens of MeV to a few GeV—a complex, multi-scale and multi-process domain spanning from low-energy nuclear physics to perturbative QCD, with no unified underlying framework currently known. In this seminar, I will provide an overview of the field, discuss recent advancements, and share examples of ongoing cross-community efforts addressing these challenges.

Pandey, Vishvas [Fermilab]↗
DOE OSTI2025

Coupling between collective modes in the deformed 98 Zr nucleus: Insights from consistent HFB+QRPA calculations with the Gogny interaction

The Zirconium isotopes exhibit structural properties that present multiple challenges to nuclear theory. Investigations of the coupling present within isoscalar modes and within isovector modes are scarce but important for advancing our understanding of the microscopic picture of nuclei. To explore some of these underlying coupling features, and to test the predictive power of a state-of the-art nuclear structure approach, we provide a detailed analysis of the properties of 90,96,98Zr. This region includes a benchmarking case and offers insights into nuclear deformation phenomena. To investigate the coupling between collective modes in deformed nuclei, we focused our analysis on the ground and excited-state properties of these isotopes, employing a consistent approach with the axially-symmetric deformed Hartree-Fock-Bogoliubov (HFB) and the Quasiparticle Random Phase Approximation (QRPA) framework, both using the Gogny D1M force. This approach effectively describes both low-lying and giant-resonance states. We devoted special attention to the deformed 98Zr nucleus, where we confirm the existence of coupling between monopole and quadrupole excitations through the K π = 0 + QRPA components and demonstrate an analogous dipole-octupole coupling through the K π = 0 − and K π = 1 − components. Intrinsic transition densities and associ ated radial projections illustrate the coupling. Our work complements and extends earlier studies carried out using density-functional-based methods and notably, we included the complete Coulomb interaction also in the pairing fields, i.e. we treat terms exactly that are approximated in typical calculations that use the Gogny D1 and D2 interaction families.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗