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DOE OSTI2023

Direct LiF imaging diagnostics on refractive X-ray focusing at the EuXFEL High Energy Density instrument

The application of fluorescent crystal media in wide-range X-ray detectors provides an opportunity to directly image the spatial distribution of ultra intense X-ray beams including investigation of the focal spot of free-electron lasers. Here the capabilities of the micro- and nano-focusing X-ray refractive optics available at the High Energy Density instrument of the European XFEL are reported, as measured in situ by means of a LiF fluorescent detector placed into and around the beam caustic. The intensity distribution of the beam focused down to several hundred nanometers was imaged at 9 keV photon energy. A deviation from the parabolic surface in a stack of nanofocusing Be compound refractive lenses (CRLs) was found to affect the resulting intensity distribution within the beam. Comparison of experimental patterns in the far field with patterns calculated for different CRL lens imperfections allowed the overall inhomogeneity in the CRL stack to be estimated. The precise determination of the focal spot size and shape on a sub-micrometer level is essential for a number of high energy density studies requiring either a pin-size backlighting spot or extreme intensities for X-ray heating.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2023

Towards the Quantum Internet: Entanglement Rate Analysis of High-Efficiency Electro-Optic Transducer

Coherent microwave-optical photon conversion is a key enabling technology for the Quantum Internet, since it allows entanglement distribution among superconducting-based network nodes. A high-efficiency electro-optic transducer based on three-dimensional superconducting radio-frequency (SRF) technology has recently been proposed at Fermilab. In this paper, we evaluate the impact of Fermilab's transduction hardware on the entanglement generation probability and the entanglement rate, which are two critical metrics from a communication engineering perspective. Furthermore, we provide some guidelines to increase the direct entanglement rate, i.e., the rate before any entanglement purification process. Our analysis shows that, through high-efficiency transduction, it is possible to reduce the network overhead. This preliminary work paves the way toward distantly interconnected superconducting quantum processors.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

NASA NTRS1978

Ultraviolet-photoproduced organic solids synthesized under simulated Jovian conditions - Molecular analysis

In an earlier paper, Khare and Sagan reported the production of a brownish polymeric material from the near-ultraviolet irradiation of simulated jovian atmospheres with a low hydrogen abundance. Examination of this product indicates that hydrogen sulfide is the initial photon acceptor; the powder resulting after extraction with benzene is 84 percent sulfur, largely S8. In results reported here, the remaining 16 percent was pyrolyzed and then examined by gas chromatography-mass spectrometry. Pyrolysis at 450 C yielded a series of alkanes, alkenes, C3-alkylbenzenes, aromatics, thiophenes, alkylthiophenes, alkylmercaptans, alkyldisulfides, together with the nitrogenous compounds hydrogen cyanide, methyl cyanide, alkylisothiocyanates, acrylonitrile, and allylisothiocyanates. Some of these compounds might be sought on Jupiter and Saturn and their satellites by remote infrared and ultraviolet spectroscopy and directly by entry probes.

Khare, B. N.↗

NASA NTRS1992

Tidal heating and mass loss in neutron star binaries - Implications for gamma-ray burst models

A neutron star in a close binary orbit around another neutron star (or stellar-mass black hole) spirals inward owing to gravitational radiation. We discuss the effects of tidal dissipation during this process. Tidal energy dissipated in the neutron star's core escapes mainly as neutrinos, but heating of the crust, and outward diffusion of photons, blows off the outer layers of the star. This photon-driven mass loss precedes the final coalescence. The presence of this eject material impedes the escape of gamma-rays created via neutrino interactions. If an e(+) - e(-) fireball, created in the late stages of coalescence, were loaded with (or surrounded by) material with the mean column density of the ejecta, it could not be an efficient source of gamma-rays. Models for cosmologically distant gamma-rays burst that involve neutron stars must therefore be anisotropic, so that the fireball expands preferentially in directions where the column density of previously blown-off material is far below the spherically averaged value which we have calculated. Some possible 'scenarios' along these lines are briefly discussed.

Meszaros, P.↗

NASA NTRS2012

Development of Field-Controlled Smart Optic Materials (ScN, AlN) with Rare Earth Dopants

The purpose of this investigation is to develop the fundamental materials and fabrication technology for field-controlled spectrally active optics that are essential for industry, NASA, and DOD applications such as: membrane optics, filters for LIDARs, windows for sensors, telescopes, spectroscopes, cameras, flat-panel displays, etc. ScN and AlN thin films were fabricated on c-axis Sapphire (0001) or quartz substrate with the RF and DC magnetron sputtering. The crystal structure of AlN in fcc (rocksalt) and hcp (wurtzite) were controlled. Advanced electrical characterizations were performed, including I-V and Hall Effect Measurement. ScN film has a free carrier density of 5.8 x 10(exp 20)/per cubic centimeter and a conductivity of 1.1 x 10(exp 3) per centimeter. The background ntype conductivity of as-grown ScN has enough free electrons that can readily interact with the photons. The high density of free electrons and relatively low mobility indicate that these films contain a high level of shallow donors as well as deep levels. Also, the UV-Vis spectrum of ScN and AlN thin films with rare earth elements (Er or Ho) were measured at room temperature. Their optical band gaps were estimated to be about 2.33eV and 2.24eV, respectively, which are obviously smaller than that of undoped thin film ScN (2.4eV). The red-shifted absorption onset gives direct evidence for the decrease of band gap (Eg) and the energy broadening of valence band states are attributable to the doping. As the doped elements enter the ScN crystal lattices, the localized band edge states form at the doped sites with a reduction of Eg. Using a variable angle spectroscopic ellipsometer, the decrease in refractive index with applied field is observed with a smaller shift in absorption coefficient.

Kim, Hyun-Jung↗

NASA NTRS2012

The Extreme Ultraviolet (EUV) Instrument for the MAVEN Mission

The Mars Atmosphere and Volatile Evolution Mission (MAVEN) will explore the variability in the planet's upper atmosphere and ionosphere that is dominated by interactions with the sun, specifically the high-energy photons in the soft X-ray and extreme ultraviolet wavelengths as well as interactions with the solar wind. Scientists will use MAVEN data to determine the current loss rate of volatile compounds from the Mars atmosphere, then extrapolate back in time in order to give historical estimations of state of the Mars atmosphere and climate, its ability to sustain liquid water, and the potential for the Martian habitability. The EUV instrument is critical in measuring the Space Weather driver of this atmospheric variability. It will directly observe a three EUV wavelength ranges and their variability due to solar flares (time scales of seconds to hours) as well as active region evolution (months), which will then act as proxies for a model to determine the entire 0.1-200 nm solar spectrum at all times during the MAVEN mission. These EUV measurements and models results will compliment the other instruments that will provide direct in-situ as well as remote sensing observations of the Martian atmospheric response to this solar driver. This presentation will be an introduction of this instrument and its science measurements and goals to the larger community, as well as a status report on its progress.

Chamberlin, Phillip C.↗

DOE OSTI2022

Studies of BONuS12 Radial GEM Detector and TCS Beam Spin Asymmetry in CLAS12

The Barely Offshell Nucleon Structure (BONuS12) experiment adopted the concept of spectator tagging technique to study the nearly-free neutron structure function Fn2 in the CLAS12 of Jefferson Lab. A novel Radial Time Projection Chamber (RTPC) detector was built, tested and integrated into the CLAS12 system to detect a back-moving low momentum tagged proton in d(e,ep)X deep-inelastic scattering. It was a 40 cm long gaseous detector consisting of 3 layers of cylindrical GEM foils for the charge amplification, with the data readout directly from the surrounding padboard. The RTPC detected the recoiling spectator proton, in coincidence with the scattered electron in the CLAS12. Nucleon structure functions are directly related to the partonic functions, quarks momentum distribution in one dimension. A Generalized Parton Distribution (GPD) came to the lime-light as it encodes the information of both longitudinal momentum and transverse position of partons inside the nucleons. Factorization of hard process such as DVCS allows to access GPDs. Timelike Compton Scattering (TCS), ?p ? ??p, is another process that allows to access the GPDs. TCS is studied experimentally in the CLAS12 of Jefferson lab using the quasi-real photoproduction of time-like photon which eventually decays to lepton pair. This dissertation presents the concept of spectator tagging in BONuS12, and the research and development efforts during the BONuS12 preparation leading up to the successful data-taking during spring and summer 2020. In addition, analysis framework to extract the beam spin asymmetry of TCS events through the CLAS12 Run group A data is presented.

Poudel, Jiwan↗

DOE OSTI2021

Observation of Forward Neutron Multiplicity Dependence of Dimuon Acoplanarity in Ultraperipheral Pb-Pb Collisions at $\sqrt{s_{NN}}$ = 5.02 TeV

The first measurement of the dependence of $γγ → μ^+μ^–$ production on the multiplicity of neutrons emitted very close to the beam direction in ultraperipheral heavy ion collisions is reported. Data for lead-lead interactions at $\sqrt{s_{NN}}$ = 5.02 TeV, with an integrated luminosity of approximately 1.5 nb –1 , are collected using the CMS detector at the LHC. The azimuthal correlations between the two muons in the invariant mass region 8 < $m_{μμ}$ < 60 GeV are extracted for events including 0, 1, or at least 2 neutrons detected in the forward pseudorapidity range |η| > 8.3. The back-to-back correlation structure from leading-order photon-photon scattering is found to be significantly broader for events with a larger number of emitted neutrons from each nucleus, corresponding to interactions with a smaller impact parameter. This observation provides a data-driven demonstration that the average transverse momentum of photons emitted from relativistic heavy ions has an impact parameter dependence. These results provide new constraints on models of photon-induced interactions in ultraperipheral collisions. They also provide a baseline to search for possible final-state effects on lepton pairs caused by traversing a quark-gluon plasma produced in hadronic heavy ion collisions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2021

Observation of new excited ${B} ^0_{s}$ states

A structure is observed in the ${B} ^{\pm }{K} ^{\mp }$ mass spectrum in a sample of proton–proton collisions at centre-of-mass energies of 7, 8, and 13 TeV, collected with the LHCb detector and corresponding to a total integrated luminosity of 9$\,\text {fb} ^{-1}$. The structure is interpreted as the result of overlapping excited ${B} ^0_{s}$ states. With high significance, a two-peak hypothesis provides a better description of the data than a single resonance. Under this hypothesis the masses and widths of the two states, assuming they decay directly to ${B} ^{\pm }{K} ^{\mp }$, are determined to be $\begin{aligned} m_1&= 6063.5 \pm 1.2 \text { (stat)} \pm 0.8\text { (syst)}\,\text {Me}\text {V}, \\ \Gamma _1&= 26 \pm 4 \text { (stat)} \pm 4\text { (syst)}\,\text {Me}\text {V}, \\ m_2&= 6114 \pm 3 \text { (stat)} \pm 5\text { (syst)}\,\text {Me}\text {V}, \\ \Gamma _2&= 66 \pm 18 \text { (stat)} \pm 21\text { (syst)}\,\text {Me}\text {V}. \end{aligned}$ Alternative values assuming a decay through ${B} ^{*\pm }{K} ^{\mp }$, with a missing photon from the $B^{*\pm } \rightarrow B^{\pm }\gamma $ decay, which are shifted by approximately 45 $\,\text {Me}$V, are also determined. The possibility of a single state decaying in both channels is also considered. The ratio of the total production cross-section times branching fraction of the new states relative to the previously observed $B_{s2}^{*0}$ state is determined to be $0.87 \pm 0.15 \text { (stat)} \pm 0.19 \text { (syst)}$.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2021

Efficiency of bulk perovskite-sensitized upconversion: Illuminating matters

Photon upconversion via triplet–triplet annihilation could allow for the existing efficiency limit of single junction solar cells to be surpassed. Indeed, efficient upconversion at subsolar fluences has been realized in bulk perovskite-sensitized systems. Many questions have remained unanswered, in particular, regarding their behavior under photovoltaic operating conditions. Here, we investigate the impact of repeated and continuous illumination on bilayer perovskite/rubrene upconversion devices. We find that variations of the underlying perovskite carrier recombination dynamics greatly impact the upconversion process. Trap filling and triplet sensitization are in direct competition: more saturated trap states in the perovskite and, thus, longer underlying perovskite photoluminescence lifetimes allow for an increased number of carriers to diffuse to the perovskite/rubrene interface and undergo charge extraction to the triplet state of rubrene. As a result, the upconversion efficiency is greatly influenced by the underlying trap density: the upconverted photoluminescence intensity increases by two orders of magnitude under continuous illumination for 4 h. This shows that the upconversion efficiency is difficult to define for this system. Importantly, these results indicate that perovskite-sensitized upconversion devices exhibit peak performance under continuous illumination, which is a requirement for their successful integration into photovoltaics to help overcome the Shockley–Queisser limit in single junction solar cells.

VanOrman, Zachary A. (ORCID:000000027773012X)↗

DOE OSTI2024

Measurement of atomic oxygen densities using TALIF on a dielectric barrier discharge: insights into the volume above a micro cavity plasma array

Dielectric barrier discharges, particularly micro cavity plasma arrays, offer significant potential for plasma-catalytic research due to their ability to ignite plasma in direct contact with a catalytic surface, enabling the observation of plasma-surface interactions. A key factor in their application is the generation of reactive species, such as atomic oxygen, within the cavities. These species can interact with both the surface (e.g. for activation or cleaning) and the gas being treated (e.g. for oxidation). Given the central role of oxygen atoms in plasma catalysis and their use as a model for more complex species, this work investigates the transport of these atoms out of the cavities. Two-photon absorption laser-induced fluorescence spectroscopy with picosecond laser excitation is performed in the volume above the cavities. The results are compared with a basic diffusion model. The reactor operates with a He/O 2 mixture at a flow rate of 1 slm and atmospheric pressure. Densities of up to 10 16 cm -3 are measured near the surface. Time-dependent measurements show that, at a distance of 350 µm from the surface, a density equilibrium is reached within less than 3 ms of reactor operation. Decay times due to ozone formation after the reactor is turned off are on a similar scale. Spatially resolved measurements show that the oxygen density decreases exponentially from the surface but remains detectable up to approximately 1 mm above the surface, indicating significant application potential. Variations in the O 2 admixture show a density maximum at 0.4%, confirming previous helium state enhanced actinometry measurements within the cavities.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

DOE OSTI2025

Portal matter models of kinetic mixing with two light dark gauge bosons

The kinetic mixing (KM) portal mandates the existence of at least one new gauge boson, the dark photon (DP) based on the group 𝑈⁢(1) 𝐷 , which mixes with the Standard Model (SM) photon via loops of other new heavy particles carrying both SM and dark charges called portal matter (PM). Arguments exist based on the renormalization group equations running of the 𝑈⁢(1) 𝐷 gauge coupling suggesting that at higher scales 𝑈⁢(1) 𝐷 becomes part of a more complex non-Abelian group, a simple example being just the SM-like 𝐺 𝐷 =𝑆⁢𝑈⁢(2)𝐼 ×𝑈⁢(1) 𝑌 𝐼 . In our past analyses, it was always assumed that 𝐺 𝐷 broke in a SM-like manner directly to the DP’s 𝑈⁢(1) 𝐷 which then subsequently broke at low energies ≲1 GeV. However, this need not be the case, and 𝐺 𝐷 can instead break to 𝑈⁢(1) 𝑇 3⁢𝐼 ×𝑈⁢(1) 𝑌 𝐼 , with 𝑇 3⁢𝐼 being the diagonal generator of 𝑆⁢𝑈⁢(2) 𝐼 , now producing two light gauge bosons which obtain masses at the ≲1 GeV scale. In this paper, we explore the phenomenology of a very simple realization of this kind of alternative setup employing non-Abelian KM and having a minimal, leptonlike PM sector, demonstrating its distinctive nature in comparison to the previously examined symmetry breaking path. The effects of interference between these gauge bosons on thermal dark matter annihilation, the production of new heavy gauge, and Higgs and PM states at colliders, as well as the corresponding signatures for the light dark gauge bosons are examined. Collider signatures of this setup are found to be particularly challenging.

extensions of Higgs sector↗

NASA NTRS2011

A Deterministic Electron, Photon, Proton and Heavy Ion Radiation Transport Suite for the Study of the Jovian System

A deterministic suite of radiation transport codes, developed at NASA Langley Research Center (LaRC), which describe the transport of electrons, photons, protons, and heavy ions in condensed media is used to simulate exposures from spectral distributions typical of electrons, protons and carbon-oxygen-sulfur (C-O-S) trapped heavy ions in the Jovian radiation environment. The particle transport suite consists of a coupled electron and photon deterministic transport algorithm (CEPTRN) and a coupled light particle and heavy ion deterministic transport algorithm (HZETRN). The primary purpose for the development of the transport suite is to provide a means for the spacecraft design community to rapidly perform numerous repetitive calculations essential for electron, proton and heavy ion radiation exposure assessments in complex space structures. In this paper, the radiation environment of the Galilean satellite Europa is used as a representative boundary condition to show the capabilities of the transport suite. While the transport suite can directly access the output electron spectra of the Jovian environment as generated by the Jet Propulsion Laboratory (JPL) Galileo Interim Radiation Electron (GIRE) model of 2003; for the sake of relevance to the upcoming Europa Jupiter System Mission (EJSM), the 105 days at Europa mission fluence energy spectra provided by JPL is used to produce the corresponding dose-depth curve in silicon behind an aluminum shield of 100 mils ( 0.7 g/sq cm). The transport suite can also accept ray-traced thickness files from a computer-aided design (CAD) package and calculate the total ionizing dose (TID) at a specific target point. In that regard, using a low-fidelity CAD model of the Galileo probe, the transport suite was verified by comparing with Monte Carlo (MC) simulations for orbits JOI--J35 of the Galileo extended mission (1996-2001). For the upcoming EJSM mission with a potential launch date of 2020, the transport suite is used to compute the traditional aluminum-silicon dose-depth calculation as a standard shield-target combination output, as well as the shielding response of high charge (Z) shields such as tantalum (Ta). Finally, a shield optimization algorithm is used to guide the instrument designer with the choice of graded-Z shield analysis.

Norman, Ryan B.↗

NASA NTRS2014

Testing the Solar Probe Cup, an Instrument Designed to Touch the Sun

Solar Probe Plus will be the first, fastest, and closest mission to the sun, providing the first direct sampling of the sub-Alfvenic corona. The Solar Probe Cup (SPC) is a unique re-imagining of the traditional Faraday Cup design and materials for immersion in this high temperature environment. Sending an instrument of this type into a never-seen particle environment requires extensive characterization prior to launch to establish sufficient measurement accuracy and instrument response. To reach this end, a slew of tests for allowing SPC to see ranges of appropriate ions and electrons, as well as a facility that reproduces solar photon spectra and fluxes for this mission. Having already tested the SPC at flight like temperatures with no significant modification of the noise floor, we recently completed a round of particle testing to see if the deviations in Faraday Cup design fundamentally change the operation of the instrument. Results and implications from these tests will be presented, as well as performance comparisons to cousin instruments such as those on the WIND spacecraft.

Whittlesey, Phyllis L.↗

DOE OSTI2024

Rethinking Coherent Diffraction Instruments for High Brightness Sources

Over the past two decades, exceptional progress has been made providing coherent x-ray beams at both high-brightness synchrotron sources and x-ray free electron lasers (XFEL). The availability of these coherent x-rays has led to a surge in instruments that exploit x-ray coherence for either x-ray photon correlation spectroscopy (XPCS) or coherent diffraction imaging (CDI). A key to these techniques has been to resolve, or at least nearly resolve, the speckles associated with the scattering from structural disorder. Given practical limits on detector pixel size, this requires long sample-to-detector distances. This paper presents numerical simulations of an instrument that can efMiciently provide a long sample-detector distance while maintaining the ability to rapidly set momentum transfer by inserting crystals with different order in the incident beam, thus changing in incident direction instead of moving the detector.

Fuoss, Paul H↗

DOE OSTI2024

Nonlinear wavepacket dynamics in proximity to a stationary inflection point

A stationary inflection point (SIP) in the Bloch dispersion relation of a periodic waveguide is an exceptional point degeneracy where three Bloch eigenmodes coalesce, forming the so-called frozen mode with a divergent amplitude and vanishing group velocity of its propagating component. For this work, we have developed a theoretical framework to study the time evolution of wavepackets centered at an SIP. Analysis of the evolution of the statistical moment distribution of linear pulses shows a strong deviation from the conventional ballistic wavepacket dynamics in dispersive media. The presence of nonlinear interactions dramatically changes the situation, resulting in a mostly ballistic propagation of nonlinear wavepackets with the speed and even the direction of propagation essentially dependent on the wavepacket amplitude. Such a behavior is unique to nonlinear wavepackets centered at an SIP and can be used for the realization of a novel family of beam power routers for classical waves.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2023

Modeling of Radiative Emission from Shallow Color Centers in Single Crystalline Diamond

Optically active defects in diamond are widely used as bright single-photon sources for quantum sensing, computing, and communication. For many applications, it is useful to place the emitter close to the diamond surface, where the radiative properties of the emitter are strongly modified by its dielectric environment. It is well-known that the radiative power from an electric dipole decreases as the emitter approaches an interface with a lower-index dielectric, leading to an increase in the radiative lifetime. For emitters in crystalline solids, modeling of this effect needs to take into account the crystal orientation and direction of the surface cut, which can greatly impact the emission characteristics. In this paper, a framework for analyzing the emission rates of shallow (<100 nm) defects is provided, in which optical transitions are derived from electric dipoles in a plane perpendicular to their spin axis. The calculations for the depth-dependent radiative lifetime for color centers in (100)-, (110)-, and (111)-cut diamond are presented, which can be extended to other vacancy defects in diamond.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2024

Three-dimensional reconstruction of laser-direct-drive inertial confinement fusion hot-spot plasma from x-ray diagnostics on the OMEGA laser facility (invited)

A deep-learning convolutional neural network (CNN) is used to infer, from x-ray images along multiple lines of sight, the low-mode shape of the hot-spot emission of deuterium–tritium (DT) laser-direct-drive cryogenic implosions on OMEGA. The motivation of this approach is to develop a physics-informed 3-D reconstruction technique that can be performed within minutes to facilitate the use of the results to inform changes to the initial target and laser conditions for the subsequent implosion. The CNN is trained on a 3D radiation-hydrodynamic simulation database to relate 2D x-ray images to 3D emissivity at stagnation. The CNN accounts for the lack of an absolute spatial reference and the different bands of photon energies in the x-ray images. While previous works studied the effect of mode-1 asymmetries on implosion performance using nuclear diagnostics, this work focuses on the effect of mode 2 inferred from x-ray diagnostics on implosion performance. A current analysis of 19 DT cryogenic implosions indicates there is an upper limit of ~20% reduction in the neutron yield caused by an ℓ = 2 amplitude for ℓ 2 /ℓ 0 ≤ 0.32. Here, these conclusions are supported by 2D simulations.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗