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All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Attosecond-pump attosecond-probe x-ray spectroscopy of liquid water

Attosecond-pump/attosecond-probe experiments have long been sought as the most straightforward method for observing electron dynamics in real time. Although there has been much success with overlapped near-infrared femtosecond and extreme ultraviolet attosecond pulses combined with theory, true attosecond-pump/attosecond-probe experiments have been limited. Here we used a synchronized attosecond x-ray pulse pair from an x-ray free-electron laser to study the electronic response to valence ionization in liquid water through all x-ray attosecond transient absorption spectroscopy (AX-ATAS). Our analysis showed that the AX-ATAS response is confined to the subfemtosecond timescale, eliminating any hydrogen atom motion and demonstrating experimentally that the 1b 1 splitting in the x-ray emission spectrum is related to dynamics and is not evidence of two structural motifs in ambient liquid water.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

Feasibility study of heavy ion physics program at NICA

There are strong experimental and theoretical evidences that in collisions of heavy ions at relativistic energies nuclear matter undergoes a phase transition to the deconfined state—Quark Gluon Plasma. The caused energy region of such transition was not found at high energy at SPS and RHIC and search for this energy is shifted to lower energies, which will be covered by the future NICA (Dubna), FAIR (Darmstadt) facilities and BES II at RHIC. Fixed target and collider experiments at the NICA facility will work at the energy range from a few AGeV up to √( S{sub NN}) = 11 GeV GeV and will study the most interesting area on the nuclear matter phase diagram. The most remarkable results were observed in the study of collective phenomena occurring in the early stage of nuclear collisions. Investigation of the collective flow will provide information on Equation of State (EoS) for nuclear matter. Study of the Event-by-Event fluctuations and correlations can give us signals of critical behavior of the system. Femtoscopy analysis provides the space-time history of the collisions. Also, it was found that baryon stopping power revealing itself as a “wiggle” in excitation function of curvature of the (net)proton rapidity spectrum relates to the order of the phase transition. The available observations of an enhancement of dilepton rates at low invariant masses may serve as a signal of the chiral symmetry restoration in hot and dense matter. Due to this fact, measurements of the dilepton spectra are considered to be an important part of the NICA physics program. The study of strange particles and hypernuclei production gives additional information on the EoS and “strange” axis of the QCD phase diagram. In this paper a feasibility of the considered investigations is shown by the detailed Monte Carlo simulations applied to the planned experiments (BM@N, MPD) at NICA.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2020

ARES. III. Unveiling the Two Faces of KELT-7 b with HST WFC3

We present the analysis of the hot-Jupiter KELT-7 b using transmission and emission spectroscopy from the Hubble Space Telescope, both taken with the Wide Field Camera 3. Our study uncovers a rich transmission spectrum that is consistent with a cloud-free atmosphere and suggests the presence of H{sub 2}O and H{sup −}. In contrast, the extracted emission spectrum does not contain strong absorption features and, although it is not consistent with a simple blackbody, it can be explained by a varying temperature–pressure profile, collision induced absorption, and H{sup −}. KELT-7 b had also been studied with other space-based instruments and we explore the effects of introducing these additional data sets. Further observations with Hubble, or the next generation of space-based telescopes, are needed to allow for the optical opacity source in transmission to be confirmed and for molecular features to be disentangled in emission.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2017

Evidence for Relativistic Disk Reflection in the Seyfert 1h Galaxy/ULIRG IRAS 05189–2524 Observed by NuSTAR and XMM-Newton

We present a spectral analysis of the NuSTAR and XMM-Newton observations of the Seyfert 1h galaxy/ULIRG IRAS 05189–2524 taken in 2013. We find evidence for relativistic disk reflection in the broadband X-ray spectrum: a highly asymmetric broad Fe Kα emission line extending down to 3 keV and a Compton scattering component above 10 keV. Physical modeling with a self-consistent disk reflection model suggests that the accretion disk is viewed at an intermediate angle with a supersolar iron abundance, and a mild constraint can be put on the high-energy cutoff of the power-law continuum. We test the disk reflection modeling under different absorption scenarios. A rapid black hole spin is favored; however, we cannot place a model-independent tight constraint on the value. The high reflection fraction (R{sub ref} ≃ 2.0–3.2) suggests that the coronal illuminating source is compact and close to the black hole (lying within 8.7 R{sub g} above the central black hole), where light-bending effects are important.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2025

Validation of the DESI-DR1 3x2-pt analysis: scale cut and shear ratio tests

Combined survey analyses of galaxy clustering and weak gravitational lensing (3x2-pt studies) will allow new and accurate tests of the standard cosmological model. However, careful validation is necessary to ensure that these cosmological constraints are not biased by uncertainties associated with the modelling of astrophysical or systematic effects. In this study we validate the combined 3x2-pt analysis of the Dark Energy Spectroscopic Instrument Data Release 1 (DESI-DR1) spectroscopic galaxy clustering and overlapping weak lensing datasets from the Kilo-Degree Survey (KiDS), the Dark Energy Survey (DES), and the Hyper-Suprime-Cam Survey (HSC). By propagating the modelling uncertainties associated with the non-linear matter power spectrum, non-linear galaxy bias and baryon feedback, we design scale cuts to ensure that measurements of the matter density and the amplitude of the matter power spectrum are biased by less than 30% of the statistical error. We also test the internal consistency of the data and weak lensing systematics by performing new measurements of the lensing shear ratio. We demonstrate that the DESI-DR1 shear ratios can be successfully fit by the same model used to describe cosmic shear correlations, and analyse the additional information that can be extracted about the source redshift distributions and intrinsic alignment parameters. This study serves as crucial preparation for the upcoming cosmological parameter analysis of these datasets.

Emas, N. [Swinburne U., Ctr. Astrophys. Supercompu↗
DOE OSTI2017

Synthesis, Spectral Characterization, Thermal and Optical Studies of Novel Complexes: 4-(Dimethylamino)benzylidene-4-acetamideaniline and 4-(Dimethylamino)benzylidene-4-nitroaniline

The phase diagram representing solid–liquid equilibrium of entire range of composition and thermodynamic studies of two binary organic systems of 4-dimethylaminobenzaldehyde (DMAB) with two NLO active compounds, p-aminoacetanilide (PAA) and p-nitroaniline (PNA), have been studied by solid state synthetic route. Both systems are independently forming a new entity called intermolecular complex (IMC) and two eutectics on either side of intermolecular complexes. The various thermodynamic parameters such as heat of mixing, entropy of fusion, roughness parameter, interfacial energy and excess thermodynamic functions of IMCs and eutectics were calculated using the heat of fusion values. The TGA and DTA studies were performed to understand the physico-chemical, thermal behavior and unique identity of newly synthesized organic complexes, 4-(dimethylamino)benzylidene-4-acetamideaniline (DMABPAA) and 4-(dimethylamino)benzylidene-4-nitroaniline (DMABPNA), and their respective enthalpy of fusion values were found to be 30.01 and 37.26 kJ mol{sup − 1}. The higher melting point of both the novel complexes than their parent’s compounds reveal the strong molecular interaction between parent components to yield the complex. The FTIR spectral analysis predicts the disappearance of aldehyde peaks of DMAB and NH{sub 2} peaks of PAA and PNA while the appearance of entirely new peaks than that of parent’s compounds are the supportive for the formation of new molecular entities. These findings are further supported by FTNMR spectrum studies by observation of disappearance of proton peak of aldehyde of DMAB and amine peaks of PAA and PNA rather formation of new imine proton peak or peaks were observed. The appearance of new peaks in Powder XRD of complexes than those of parent components is further indicative for the formation of complexes. The absorption spectrum of DMABPAA and DMABPNA showed intra-molecular charge-transfer (ICT) excited state absorption at 258 and 241 nm, respectively. Both the IMCs, DMABPAA and DMABPNA, show strong fluorescence with quantum yield 0.66 and 0.93, respectively, in methanol solution.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2026

Instantaneous difference frequency locking observed during toroidicity-induced Alfvén eigenmode coupling in the DIII-D tokamak

In magnetic confinement fusion, toroidicity-induced Alfvén eigenmodes (TAEs) are well-studied, weakly stable solutions of the linearized ideal magnetohydrodynamic equations. Driven unstable by suprathermal populations of energetic particles, TAE pose a key vulnerability to the confinement of high-energy alpha particles generated by fusion reactions. Hence, it is paramount to understand TAE dynamics if a working reactor is to be realized. In this work, we detect and characterize signatures of nonstationary nonlinear coupling between TAE using a novel, time-resolved bispectral analysis; results are supported by analytic signal of band-passed data. Crucially, a stationary phase relationship between two TAE and a nascent low frequency fluctuation is observed precisely when the triple product of magnetic fluctuation amplitudes is enhanced. Local mode number and frequency spectrum, gleaned from beam-emission spectroscopy, corroborates simultaneous satisfaction of nonlinear matching conditions, and provides a tool to identify theorized pathways of energy transfer, e.g. TAE parametric instability.

bispectral analysis↗
DOE OSTI2016

Nondestructive Analysis of MET-5 Drum at TA35 Building 2 A-Wing Vault.

Measurements using a mechanically cooled portable high purity germanium HPGe Ortec detective were taken of a type B drum Serial number R-1157 to determine if any radioactive material was inside. The Drum, R-1157, spectrum was analyzed using PeakEasy 4.84 and a visual look at the spectrum showed background radiation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

HFIR Core Modeling and Analysis for the PROSPECT Reactor Antineutrino Experiment

Nuclear reactors have been employed as a copious source of antineutrinos for over six decades. Research initially directed at the study of antineutrino physics has led to applications of these highly penetrating particles to reactor safeguards because the antineutrino flux and spectrum can be related to the state of the reactor core, including burnup evolution. One of the main challenges of antineutrino-based safeguards is operation of the detectors near surface (within the reactor containment or in the close proximity). Lack of overburden results in increased contribution to the detector noise from cosmic radiation. Similarly to safeguards, experiments to definitively confirm or exclude the existence of sterile neutrino oscillations require detector technologies capable of operating at short baselines (tens of meters) at the surface. The Precision Reactor Oscillation and Spectrum Experiment (PROSPECT) at the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL) is an experiment with a main objective to make a precision measurement of the flux and energy spectrum of antineutrinos emitted from nuclear reactors in order to search for the oscillation signature of sterile neutrinos. Fissions of highly-enriched uranium of HFIR will serve as a source of antineutrinos. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2023

Multidimensional quantitative phenotypic and molecular analysis reveals neomorphic behaviors of p53 missense mutants

Abstract Mutations in the TP53 tumor suppressor gene occur in >80% of the triple-negative or basal-like breast cancer. To test whether neomorphic functions of specific TP53 missense mutations contribute to phenotypic heterogeneity, we characterized phenotypes of non-transformed MCF10A-derived cell lines expressing the ten most common missense mutant p53 proteins and observed a wide spectrum of phenotypic changes in cell survival, resistance to apoptosis and anoikis, cell migration, invasion and 3D mammosphere architecture. The p53 mutants R248W, R273C, R248Q, and Y220C are the most aggressive while G245S and Y234C are the least, which correlates with survival rates of basal-like breast cancer patients. Interestingly, a crucial amino acid difference at one position—R273C vs. R273H—has drastic changes on cellular phenotype. RNA-Seq and ChIP-Seq analyses show distinct DNA binding properties of different p53 mutants, yielding heterogeneous transcriptomics profiles, and MD simulation provided structural basis of differential DNA binding of different p53 mutants. Integrative statistical and machine-learning-based pathway analysis on gene expression profiles with phenotype vectors across the mutant cell lines identifies quantitative association of multiple pathways including the Hippo/YAP/TAZ pathway with phenotypic aggressiveness. Further, comparative analyses of large transcriptomics datasets on breast cancer cell lines and tumors suggest that dysregulation of the Hippo/YAP/TAZ pathway plays a key role in driving the cellular phenotypes towards basal-like in the presence of more aggressive p53 mutants. Overall, our study describes distinct gain-of-function impacts on protein functions, transcriptional profiles, and cellular behaviors of different p53 missense mutants, which contribute to clinical phenotypic heterogeneity of triple-negative breast tumors.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2021

Chimera Spectrum Diagnostics for Peptides Using Two-Dimensional Partial Covariance Mass Spectrometry

The rate of successful identification of peptide sequences by tandem mass spectrometry (MS/MS) is adversely affected by the common occurrence of co-isolation and co-fragmentation of two or more isobaric or isomeric parent ions. This results in so-called `chimera spectra’, which feature peaks of the fragment ions from more than a single precursor ion. The totality of the fragment ion peaks in chimera spectra cannot be assigned to a single peptide sequence, which contradicts a fundamental assumption of the standard automated MS/MS spectra analysis tools, such as protein database search engines. This calls for a diagnostic method able to identify chimera spectra to single out the cases where this assumption is not valid. Here, we demonstrate that, within the recently developed two-dimensional partial covariance mass spectrometry (2D-PC-MS), it is possible to reliably identify chimera spectra directly from the two-dimensional fragment ion spectrum, irrespective of whether the co-isolated peptide ions are isobaric up to a finite mass accuracy or isomeric. We introduce ‘3-57 chimera tag’ technique for chimera spectrum diagnostics based on 2D-PC-MS and perform numerical simulations to examine its efficiency. We experimentally demonstrate the detection of a mixture of two isomeric parent ions, even under conditions when one isomeric peptide is at one five-hundredth of the molar concentration of the second isomer.

47 OTHER INSTRUMENTATION↗
DOE OSTI2024

Insights into Tetravalent Np Speciation in HNO 3 through Spectroelectrochemistry and Multivariate Analysis

In situ optical spectroscopy, spectropotentiometry, and multivariate analysis were applied to the Np(IV) nitrate system to better understand speciation and quantify HNO 3 concentration. Thin-layer spectropotentiometry, or spectroelectrochemistry, was leveraged to isolate and stabilize Np(IV) without compromising the solution conditions and generate representative Vis-NIR absorption spectra from 0.5 to 10 M HNO 3 and benchmark the corresponding Np(IV) molar absorptivity coefficients. Spectra were described with principal component analysis (PCA) to identify the purest Np(IV) absorbance spectra among other oxidation states [e.g., Np(V/VI)] at each acid concentration and then to identify the primary sources of variance within each Np(IV) spectrum with respect to Np(IV) nitrate complexes. Then, partial least-squares regression (PLSR) and support vector regression (SVR) models were built to predict HNO 3 concentration from the Np(IV) spectral data. The nonlinear SVR model outperformed the linear PLSR model for the HNO 3 concentration predictions. Finally, the inclusion of spectra collected in edge and center point HNO 3 concentrations in the calibration set was determined to be crucial for producing models with strong predictive capabilities. The multivariate approach used in this study makes it possible to quantify HNO 3 concentration solely based on Np(IV) absorption spectra, which is essential to quantifying processing streams in various online monitoring applications.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2016

The Nature of Secondary Interactions at Electrophilic Metal Sites of Molecular and Silica-Supported Organolutetium Complexes from Solid-State NMR Spectroscopy

Lu[CH(SiMe 3 ) 2 ] 3 reacts with [SiO 2-700 ] to give [(≡SiO)Lu[CH(SiMe 3 ) 2 ] 2 ] and CH 2 (SiMe 3 ) 2 . [(≡SiO)Lu[CH(SiMe 3 ) 2 ] 2 ] is characterized by solid-state NMR and EXAFS spectroscopy, which show that secondary Lu···C and Lu···O interactions, involving a γ-CH 3 and a siloxane bridge, are present. From X-ray crystallographic analysis, the molecular analogues Lu[CH(SiMe 3 ) 2 ] 3-x [O-2,6-tBu-C 6 H 3 ] x (x = 0-2) also have secondary Lu···C interactions. The 1 H NMR spectrum of Lu[CH(SiMe 3 ) 2 ] 3 shows that the -SiMe 3 groups are equivalent to -125°C and inequivalent below that temperature, δ‡(T c = 148 K)= 7.1 kcal mol -1 . Both -SiMe 3 groups in Lu[CH(SiMe 3 ) 2 ] 3 have 1 J CH = 117 ± 1 Hz at -140°C. The solid-state 13 C CPMAS NMR spectrum at 20°C shows three chemically inequivalent resonances in the area ratio of 4:1:1 (12:3:3); the J-resolved spectra for each resonance give 1 J CH = 117 ± 2 Hz. The 29 Si CPMAS NMR spectrum shows two chemically inequivalent resonances with different values of chemical shift anisotropy. Similar observations are obtained for Lu[CH(SiMe 3 ) 2 ] 3-x [O-2,6-tBu-C 6 H 3 ] x (x = 1 and 2). The spectroscopic data point to short Lu···Cγ contacts corresponding to 3c-2e Lu···Cγ-Siβ interactions, which are supported by DFT calculations. Calculated natural bond orbital (NBO) charges show that Cγ carries a negative charge, while Lu, Hγ, and Siβ carry positive charges; as the number of O-based ligands increases so does the positive charge at Lu, which in turns shortens the Lu···Cγ distance. Finally, the change in NBO charges and the resulting changes in the spectroscopic and crystallographic properties show how ligands and surface-support sites rearrange to accommodate these changes, consistent with Pauling's electroneutrality concept.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Experimental tests of an infrared video bolometer on Alcator C-Mod

A prototype of an infrared imaging bolometer (IRVB) was successfully tested on the Alcator C-Mod tokamak at the end of its 2016 campaign. The IRVB method interprets the power radiated from the plasma by measuring the temperature rise of a thin, ~2 μm, Pt absorber that is placed in the torus vacuum and exposed, using a pinhole camera, to the full-spectrum of plasma’s photon emission. The IRVB installed on C-Mod viewed the poloidal cross section of the core plasma and observed Ohmic and ion cyclotron range of frequency (ICRF)-heated plasmas. Analysis of total radiated power and on-axis emissivity from IRVB is summarized, and quantitative comparisons made to data from both resistive bolometers and AXUV diodes. IRVB results are clearly within a factor of two, but additional effort is needed for it to be used to fully support power exhaust research. The IRVB is shown to be immune to electromagnetic interference from ICRF which strongly impacts C-Mod’s resistive bolometers. Results of the bench-top calibration are summarized, including a novel temperature calibration method useful for IRVBs.

47 OTHER INSTRUMENTATION↗
DOE OSTI2021

Constraining the hadronic spectrum and repulsive interactions in a hadron resonance gas via fluctuations of conserved charges

We simultaneously incorporate two common extensions of the hadron resonance gas model, namely the addition of extra, unconfirmed resonances to the particle list and the excluded volume repulsive interactions. We emphasize the complementary nature of these two extensions and identify combinations of conserved charge susceptibilities that allow to constrain them separately. In particular, ratios of second-order susceptibilities like $\chi_{11}^{BQ}/\chi_2^B$ and $\chi_{11}^{BS}/\chi_2^B$ are sensitive only to the baryon spectrum, while fourth-to-second order ratios like $\chi_4^B/\chi_2^B$, $\chi_{31}^{BS}/\chi_{11}^{BS}$, or $\chi_{31}^{BQ}/\chi_{11}^{BQ}$ are mainly determined by repulsive interactions. Analysis of the available lattice results suggests the presence of both the extra states in the baryon-strangeness sector and the repulsive baryonic interaction, with indications that hyperons have a smaller repulsive core than non-strange baryons. Furthermore, the modified hadron resonance gas model presented here significantly improves the description of lattice QCD susceptibilities at chemical freeze-out and can be used for the analysis of event-by-event fluctuations in heavy-ion collisions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2024

New methods and simulations for cosmogenic induced spallation removal in Super-Kamiokande-IV

Radioactivity induced by cosmic muon spallation is a dominant source of backgrounds for 𝒪⁡(10 MeV) neutrino interactions in water Cherenkov detectors. In particular, it is crucial to reduce backgrounds to measure the solar neutrino spectrum and find neutrino interactions from distant supernovae. In this paper we introduce new techniques to locate muon-induced hadronic showers and efficiently reject spallation backgrounds. Applying these techniques to the solar neutrino analysis with an exposure of 2790 × 22.5 kton · day increases the signal efficiency by 12.6%, approximately corresponding to an additional year of detector running. Furthermore, we present the first spallation simulation at Super-Kamiokande, where we model hadronic interactions using fluka. The agreement between the isotope yields and shower pattern in this simulation and in the data gives confidence in the accuracy of this simulation, and thus opens the door to use it to optimize muon spallation removal in new data with gadolinium-enhanced neutron capture detection.

muons↗
DOE OSTI2018

Validation Study of the Spacecraft Background Activation using RHESSI Data

This document serves as a brief writeup of the work done to validate CINDER2008 and the Activation Analysis Tools in the Activation in Accelerator Radiation Environments (AARE) distribution that are used to calculate the activation of spacecraft material while in orbit [1{3]. The validation study involves replicating the decay gamma spectrum as observed onboard the RHESSI spacecraft in the high-purity germanium (HPGe) detectors after crossing the South Atlantic Anomaly (SAA) [4]. The tools involved are a suite of Python scripts, the transmutation code CINDER2008 accompanied with a suite of scripts distributed with AARE,MCNPX, and MCNP6.2 [2,5{7]. Figure 1 shows the gamma ray spectrum this study replicates as the spectrum designated \Difference".

42 ENGINEERING↗