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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2011

Nuclear Data Sheets for A = 33

The experimental data are evaluated for known nuclides of mass number A=33 (Ne, Na, Mg, Al, Si, P, S, Cl, Ar, K). Detailed evaluated level properties and related information are presented, including adopted values of level and {gamma}-ray energies, decay data (energies, intensities and placement of radiations), and other spectroscopic data. This work supersedes earlier full evaluations of A=33 published by 1990En08 (also 1998En04 update) and 1978En02. Experimental studies for the identification of the {sup 33}Ne and {sup 33}K nuclides have not met with success as yet. Values of S(n) and S(p) from systematics for {sup 33}Ne and {sup 33}K, respectively suggest that these nuclei are likely to be unstable to particle emission. The radioactive decay schemes of {sup 33}Na and {sup 33}Al seem incomplete in view of large Q values and known excitations much below than allowed by the Q values. The {sup 33}S and {sup 33}Cl nuclides remain as the most extensively studied from many different reactions and decays.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2011

The Spectroscopic study of {sup 33}Ar

The proton-rich nucleus {sup 33}Ar has been produced at the low-energy facility SPIRAL at GANIL. Spectroscopic studies of gamma and p emission of this nucleus were performed with the 'Silicon Cube' detection system. The analysis of proton and gamma singles and coincidence spectra allowed us to establish a complete decay scheme of this nucleus. The comparison of the Gamow-Teller strength distribution deduced from our experiment and the theoretical one obtained with the Shell Model permitted the determination of a quenching factor for the Gamow-Teller strength.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2011

Beta-delayed Proton-emission: Peering into Nuclear Structure

The {beta} decay data of {sup 32,33}Ar, recently revisited at the low energy line of SPIRAL at GANIL, is used to illustrate the structure information we can get from {beta}p precusors when a highly performing setup is used.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
NASA NTRS1983

Directional Solidification of Monotectic Alloys

Cooling at certain rates produced fibrous composite structures. Alloy samples melted in alumina or graphite crucibles under argon and then chillcast into 33-mm-diameter rods or sucked directly into 3-mm-bore alumina or silica tubes. Alloying not automatic with immiscible components of different densities and widely different melting points.

Hellawell, A.↗
DOE OSTI2019

Direct comparison of high voltage breakdown measurements in liquid argon and liquid xenon

As noble liquid time projection chambers grow in size their high voltage requirements increase, and detailed, reproducible studies of dielectric breakdown and the onset of electroluminescence are needed to inform their design. The Xenon Breakdown Apparatus (XeBrA) is a 5-liter cryogenic chamber built to characterize the DC high voltage breakdown behavior of liquid xenon and liquid argon. Electrodes with areas up to 33 cm 2 were tested while varying the cathode-anode separation from 1 to 6 mm with a voltage difference up to 75 kV. A power-law relationship between breakdown field and electrode area was observed. Finally, the breakdown behavior of liquid argon and liquid xenon within the same experimental apparatus was comparable.

47 OTHER INSTRUMENTATION↗
DOE OSTI2015

Pulsed electron beam propagation in argon and nitrogen gas mixture

The paper presents the results of current measurements for the electron beam, propagating inside a drift tube filled in with a gas mixture (Ar and N{sub 2}). The experiments were performed using the TEA-500 pulsed electron accelerator. The main characteristics of electron beam were as follows: 60 ns pulse duration, up to 200 J energy, and 5 cm diameter. The electron beam propagated inside the drift tube assembled of three sections. Gas pressures inside the drift tube were 760 ± 3, 300 ± 3, and 50 ± 1 Torr. The studies were performed in argon, nitrogen, and their mixtures of 33%, 50%, and 66% volume concentrations, respectively.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
NASA NTRS1998

A Generalized Fluid System Simulation Program to Model Flow Distribution in Fluid Networks

This paper describes a general purpose computer program for analyzing steady state and transient flow in a complex network. The program is capable of modeling phase changes, compressibility, mixture thermodynamics and external body forces such as gravity and centrifugal. The program's preprocessor allows the user to interactively develop a fluid network simulation consisting of nodes and branches. Mass, energy and specie conservation equations are solved at the nodes; the momentum conservation equations are solved in the branches. The program contains subroutines for computing "real fluid" thermodynamic and thermophysical properties for 33 fluids. The fluids are: helium, methane, neon, nitrogen, carbon monoxide, oxygen, argon, carbon dioxide, fluorine, hydrogen, parahydrogen, water, kerosene (RP-1), isobutane, butane, deuterium, ethane, ethylene, hydrogen sulfide, krypton, propane, xenon, R-11, R-12, R-22, R-32, R-123, R-124, R-125, R-134A, R-152A, nitrogen trifluoride and ammonia. The program also provides the options of using any incompressible fluid with constant density and viscosity or ideal gas. Seventeen different resistance/source options are provided for modeling momentum sources or sinks in the branches. These options include: pipe flow, flow through a restriction, non-circular duct, pipe flow with entrance and/or exit losses, thin sharp orifice, thick orifice, square edge reduction, square edge expansion, rotating annular duct, rotating radial duct, labyrinth seal, parallel plates, common fittings and valves, pump characteristics, pump power, valve with a given loss coefficient, and a Joule-Thompson device. The system of equations describing the fluid network is solved by a hybrid numerical method that is a combination of the Newton-Raphson and successive substitution methods. This paper also illustrates the application and verification of the code by comparison with Hardy Cross method for steady state flow and analytical solution for unsteady flow.

Majumdar, Alok↗
DOE OSTI2020

Computing for the DUNE Long-Baseline Neutrino Oscillation Experiment

This is a talk given at Computers in High Energy Physics in Adelaide, South Australia, Australia in November 2019. It is partially intended to explain the context of DUNE Computing for computing specialists. The DUNE collaboration consists of over 180 institutions from 33 countries. The experiment is in preparation now with commissioning of the first 10kT fiducial volume Liquid Argon TPC expected over the period 2025-2028 and a long data taking run with 4 modules expected from 2029 and beyond. An active prototyping program is already in place with a short test beam run with a 700T, 15,360 channel prototype of single-phase readout at the neutrino platform at CERN in late 2018 and tests of a similar sized dual-phase detector scheduled for mid-2019. The 2018 test beam run was a valuable live test of our computing model. The detector produced raw data at rates of up to ~2GB/s. These data were stored at full rate on tape at CERN and Fermilab and replicated at sites in the UK and Czech Republic. In total 1.2 PB of raw data from beam and cosmic triggers were produced and reconstructed during the six week test beam run. Baseline predictions for the full DUNE detector data, starting in the late 2020's are 30-60 PB of raw data per year. In contrast to traditional HEP computational problems, DUNE's Liquid Argon TPC data consist of simple but very large (many GB) 2D data objects which share many characteristics with astrophysical images. This presents opportunities to use advances in machine learning and pattern recognition as a frontier user of High Performance Computing facilities capable of massively parallel processing.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2015

Size dependent compressibility of nano-ceria: Minimum near 33 nm

We report the crystallite-size-dependency of the compressibility of nanoceria under hydrostatic pressure for a wide variety of crystallite diameters and comment on the size-based trends indicating an extremum near 33 nm. Uniform nano-crystals of ceria were synthesized by basic precipitation from cerium (III) nitrate. Size-control was achieved by adjusting mixing time and, for larger particles, a subsequent annealing temperature. The nano-crystals were characterized by transmission electron microscopy and standard ambient x-ray diffraction (XRD). Compressibility, or its reciprocal, bulk modulus, was measured with high-pressure XRD at LBL-ALS, using helium, neon, or argon as the pressure-transmitting medium for all samples. As crystallite size decreased below 100 nm, the bulk modulus first increased, and then decreased, achieving a maximum near a crystallite diameter of 33 nm. We review earlier work and examine several possible explanations for the peaking of bulk modulus at an intermediate crystallite size.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

Microstructure, Phase Occurrence, and Corrosion Behavior of As-Solidified and As-Annealed Al-Pd Alloys

In the present work, we studied the microstructure, phase constitution, and corrosion performance of Al{sub 88}Pd{sub 12}, Al{sub 77}Pd{sub 23}, Al{sub 72}Pd{sub 28}, and Al{sub 67}Pd{sub 33} alloys (metal concentrations are given in at.%). The alloys were prepared by repeated arc melting of Al and Pd granules in argon atmosphere. The as-solidified samples were further annealed at 700 °C for 500 h. The microstructure and phase constitution of the as-solidified and as-annealed alloys were studied by scanning electron microscopy, energy-dispersive x-ray spectroscopy, and x-ray diffraction. The alloys were found to consist of (Al), ε{sub n} (~ Al{sub 3}Pd), and δ (Al{sub 3}Pd{sub 2}) in various fractions. The corrosion testing of the alloys was performed in aqueous NaCl (0.6 M) using a standard 3-electrode cell monitored by potentiostat. The corrosion current densities and corrosion potentials were determined by Tafel extrapolation. The corrosion potentials of the alloys were found between − 763 and − 841 mV versus Ag/AgCl. An active alloy dissolution has been observed, and it has been found that (Al) was excavated, whereas Al in ε{sub n} was de-alloyed. The effects of bulk chemical composition, phase occurrence and microstructure on the corrosion behavior are evaluated. The local nobilities of ε{sub n} and δ are discussed. Finally, the conclusions about the alloy’s corrosion resistance in saline solutions are provided.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Rapid Identification of Calcium Aluminate Inclusions in Steels Using Cathodoluminescence Analysis

We propose a method to identify calcium aluminate inclusions in calcium-treated aluminum-killed steels (Ca{sub 12}Al{sub 14}O{sub 33}, CaAl{sub 4}O{sub 7}, CaAl{sub 12}O{sub 19}, and Al{sub 2}O{sub 3}) using cathodoluminescence (CL) analysis. Such inclusions result in nozzle clogging and melting of the stopper rod during continuous casting. We obtain CL images and CL spectra of calcium aluminate inclusions in model samples of calcium-treated aluminum-killed steel. The model samples are prepared by heating mixtures of Fe powder, Al powder, and Ca shot at 1550 °C in an argon atmosphere. On the basis of the CL colors and CL spectra of the calcium aluminate inclusions, we demonstrate that it is possible to distinguish Ca{sub 12}Al{sub 14}O{sub 33}, CaAl{sub 4}O{sub 7}, CaAl{sub 12}O{sub 19}, and Al{sub 2}O{sub 3} inclusions from CaAl{sub 2}O{sub 4} and Ca{sub 3}Al{sub 10}O{sub 18} inclusions, which do not cause nozzle clogging and melting of the stopper rod, by comparing CL images obtained using digital cameras with and without a built-in filter. The acquisition times for the CL images are less than 10 seconds. Thus, the method we present here can be applied for the rapid detection of harmful calcium aluminate inclusions during continuous casting. The CL spectra also provide basic information to specify compositions in agglomerated calcium aluminate inclusions.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Photo-fragmentation spectroscopy of benzylium and 1-phenylethyl cations

The electronic spectra of cold benzylium (C{sub 6}H{sub 5}-CH{sub 2}{sup +}) and 1-phenylethyl (C{sub 6}H{sub 5}-CH-CH{sub 3}{sup +}) cations have been recorded via photofragment spectroscopy. Benzylium and 1-phenylethyl cations produced from electrosprayed benzylamine and phenylethylamine solutions, respectively, were stored in a cryogenically cooled quadrupole ion trap and photodissociated by an OPO laser, scanned in parts of the UV and visible regions (600–225 nm). The electronic states and active vibrational modes of the benzylium and 1-phenylethyl cations as well as those of their tropylium or methyl tropylium isomers have been calculated with ab initio methods for comparison with the spectra observed. Sharp vibrational progressions are observed in the visible region while the absorption features are much broader in the UV. The visible spectrum of the benzylium cation is similar to that obtained in an argon tagging experiment [V. Dryza, N. Chalyavi, J. A. Sanelli, and E. J. Bieske, J. Chem. Phys. 137, 204304 (2012)], with an additional splitting assigned to Fermi resonances. The visible spectrum of the 1-phenylethyl cation also shows vibrational progressions. For both cations, the second electronic transition is observed in the UV, around 33 000 cm{sup −1} (4.1 eV) and shows a broadened vibrational progression. In both cases the S{sub 2} optimized geometry is non-planar. The third electronic transition observed around 40 000 cm{sup −1} (5.0 eV) is even broader with no apparent vibrational structures, which is indicative of either a fast non-radiative process or a very large change in geometry between the excited and the ground states. The oscillator strengths calculated for tropylium and methyl tropylium are weak. Therefore, these isomeric structures are most likely not responsible for these absorption features. Finally, the fragmentation pattern changes in the second and third electronic states: C{sub 2}H{sub 2} loss becomes predominant at higher excitation energies, for both cations.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1998

Fluoropolymer Films Deposited by Argon Ion-Beam Sputtering of Polytetrafluoroethylene

The FT-IR, XPS and UV spectra of fluoropolymer films (SPTFE-I) deposited by argon ion-beam sputtering of polytetrafluoroethylene (PTFE) were obtained and compared with prior corresponding spectra of fluoropolymer films (SPTFE-P) deposited by argon rf plasma sputtering of PTFE. Although the F/C ratios for SPTFE-I and -P (1.63 and 1.51) were similar, their structures were quite different in that there was a much higher concentration of CF2 groups in SPTFE-I than in SPTFE-P, ca. 61 and 33% of the total carbon contents, respectively. The FT-IR spectra reflect that difference, that for SPTFE-I showing a distinct doublet at 1210 and 1150 per centimeter while that for SPTFE-P presents a broad, featureless band at ca. 1250 per centimeter. The absorbance of the 1210-per centimeter band in SPTFE-I was proportional to the thickness of the film, in the range of 50-400 nanometers. The SPTFE-I was more transparent in the UV than SPTFE-P at comparable thickness. The mechanism for SPTFE-I formation likely involves "chopping off" of oligomeric segments of PTFE as an accompaniment to "plasma" polymerization of TFE monomer or other fluorocarbon fragments generated in situ from PTFE on impact with energetic Ar ions. Data are presented for SPTFE-I deposits and the associated Ar(+) bombarded PTFE targets where a fresh target was used for each run or a single target was used for a sequence of runs.

Golub, Morton A.↗
DOE OSTI2011

Preparation, crystal structures and rapid hydration of P2- and P3-type sodium chromium antimony oxides

Two new Na{sub x}[Cr{sub (1+x)/2}Sb{sub (1-x)/2}]O{sub 2} compounds have been prepared by solid-state reactions in argon. Their structures have been determined by the X-ray Rietveld method. Both new phases together with NaCrO{sub 2}-based solid solution comprise brucite-like layers of edge-shared (Cr,Sb)O{sub 6} octahedra but differ by packing mode of the layers and coordination of the interlayer Na{sup +} ions. A P3 phase exists at x{approx}0.5-0.58. It is rhombohedral (R3-bar m), a=2.966, c=16.937 A at x{approx}0.58, with 29% Na{sup +} occupancy of trigonal prisms. A P2 phase exists at x{approx}0.6-0.7. It is hexagonal (P6{sub 3}/mmc), a=2.960, c=11.190 A at x{approx}0.7, with 37% and 33% Na{sup +} occupancy of two non-equivalent trigonal prisms. Both P2 and P3 phases rapidly absorb moisture in air; packing mode is preserved, the a parameter changes slightly but c increases by 24-25%. Very high sodium ion conductivity is predicted for both P2 and P3 anhydrous phases. -- Graphical Abstract: Polyhedral presentation of layered structures of Na{sub x}[Cr{sub (1+x)/2}Sb{sub (1-x)/2}]O{sub 2}. (Cr,Sb)O{sub 6} octahedra are green. Part of the sodium prisms are open to show short distances between sodium sites which cannot be occupied simultaneously. Display Omitted highlights: > Two new layered Na{sub x}[Cr{sub (1+x)/2}Sb{sub (1-x)/2}]O{sub 2} phases, P2 and P3, have been prepared in argon. > Interlayer O-O distances are larger than in Na{sub x}(M,Ti)O{sub 2} analogs (M=Cr,Ni,Li). > As a result, both rapidly hydrate in air with c-axis expansion of 24-25%. > Bottleneck radii are also larger, and this predicts very high Na{sup +}-ion conductivity.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2014

Operation of Lanzhou all permanent electron cyclotron resonance ion source No. 2 on 320 kV platform with highly charged ions

The 320 kV platform for multi-discipline research with highly charged ions is a heavy ion beam acceleration instrument developed by Institute of Modern Physics, which is dedicated to basic scientific researches such as plasma, atom, material physics, and astrophysics, etc. The platform has delivered ion beams of 400 species for 36 000 h. The average operation time is around 5000 h/year. With the beams provided by the platform, lots of outstanding progresses were made in various research fields. The ion source of the platform is an all-permanent magnet electron cyclotron resonance ion source, LAPECR2 (Lanzhou All Permanent ECR ion source No. 2). The maximum axial magnetic fields are 1.28 T at injection and 1.07 T at extraction, and the radial magnetic field is up to 1.21 T at the inner wall of the plasma chamber. The ion source is capable to produce low, medium, and high charge state gaseous and metallic ion beams, such as H{sup +}, {sup 40}Ar{sup 8+}, {sup 129}Xe{sup 30+}, {sup 209}Bi{sup 33+}, etc. This paper will present the latest result of LAPECR2 and the routine operation status for the high voltage platform.

43 PARTICLE ACCELERATORS↗
DOE OSTI2016

Influence of pre-hydriding and quench on embrittlement of E110 alloy under LOCA conditions

The aims of present work were to investigate the corrosion behavior and residual ductility of pre-hydrided E110 alloy under LOCA conditions including the influence of cooling rate. The fragments of unirradiated and pre-hydrided cladding (9,5*8,33 mm with a 10 mm length) were used as samples. The claddings were made from an E110 sponge based alloy (finish polishing). The hydrogen concentration varied from 5 (as received) to 800 wppm. As a result of pre-hydriding δ- hydrides of zirconium have been formed into cladding material. Corrosion tests were carried out at temperatures 1100 and 1200 C. degrees in a steam (80 mg/s) and argon (25 ml/s) mixture flow. The samples were cooled by 2 regimes: the first one is cooling in the cold zone of test facility with rate about 20 C. degrees/s, the second is cooling in the cold zone of test facility with rate about 20 C. degrees/s from test temperature to 800 C. degrees and quench by dropping in to the water. The change of a sample mass was determined as a difference between initial sample mass and its mass after oxidation. The mechanical tests of oxidized claddings in a diametrical direction were carried out with the use of a universal tension testing machine at a steady deformation rate of 1 mm/min at 135 C. degrees. The investigations have established the following. The initial concentration of hydrogen has no effects on the oxidation kinetics, while the oxidation kinetics are parabolic and the breakaway oxidation is not observed. The oxide films on cladding surfaces are black and shining. There are no cracks, visual spots and peelings. The residual ductility of oxidized samples decreases with the increase of hydrogen concentration. The residual ductility of slow cooled claddings is higher than residual ductility of quenched claddings. The limiting value of ECR (Equivalent Cladding Reacted) corresponding to ductile-brittle transition as function of initial hydrogen content was evaluated. The value of residual ductility 2% was used as a ductile-brittle threshold. The limiting value of ECR for as-received E110 alloy is 18% and it decreases slowly to 15% with hydrogen content rising to 350 wppm. At hydrogen content of about 350 - 400 wppm there is a rapid change of limiting value of ECR from 15% to 8 %. At hydrogen content from 400 to 800 wppm the limiting value of ECR decreases from 8% to 3%. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2012

A portable optical emission spectroscopy-cavity ringdown spectroscopy dual-mode plasma spectrometer for measurements of environmentally important trace heavy metals: Initial test with elemental Hg

A portable optical emission spectroscopy-cavity ringdown spectroscopy (OES-CRDS) dual-mode plasma spectrometer is described. A compact, low-power, atmospheric argon microwave plasma torch (MPT) is utilized as the emission source when the spectrometer is operating in the OES mode. The same MPT serves as the atomization source for ringdown measurements in the CRDS mode. Initial demonstration of the instrument is carried out by observing OES of multiple elements including mercury (Hg) in the OES mode and by measuring absolute concentrations of Hg in the metastable state 6s6p {sup 3}P{sub 0} in the CRDS mode, in which a palm-size diode laser operating at a single wavelength 405 nm is incorporated in the spectrometer as the light source. In the OES mode, the detection limit for Hg is determined to be 44 parts per 10{sup 9} (ppb). A strong radiation trapping effect on emission measurements of Hg at 254 nm is observed when the Hg solution concentration is higher than 50 parts per 10{sup 6} (ppm). The radiation trapping effect suggests that two different transition lines of Hg at 253.65 nm and 365.01 nm be selected for emission measurements in lower (<50 ppm) and higher concentration ranges (>50 ppm), respectively. In the CRDS mode, the detection limit of Hg in the metastable state 6s6p {sup 3}P{sub 0} is achieved to be 2.24 parts per 10{sup 12} (ppt) when the plasma is operating at 150 W with sample gas flow rate of 480 mL min{sup -1}; the detection limit corresponds to 50 ppm in Hg sample solution. Advantage of this novel spectrometer has two-fold, it has a large measurement dynamic range, from a few ppt to hundreds ppm and the CRDS mode can serve as calibration for the OES mode as well as high sensitivity measurements. Measurements of seven other elements, As, Cd, Mn, Ni, P, Pb, and Sr, using the OES mode are also carried out with detection limits of 1100, 33, 30, 144, 576, 94, and 2 ppb, respectively. Matrix effect in the presence of other elements on Hg measurements has been found to increase the detection limit to 131 ppb. These elements in lower concentrations can also be measured in the CRDS mode when a compact laser source is available to be integrated into the spectrometer in the future. This exploratory study demonstrates a new instrument platform using an OES-CRDS dual-mode technique for potential field applications.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗