NIST Laboratories Research Articles

The first cut is the cheapest: optimizing Athena/X-IFU-like TES detectors resolution by filter truncation

The X-ray Integral Field Unit (X-IFU) instrument on the future ESA mission Athena X-ray Observatory is a cryogenic micro-calorimeter array of Transition Edge Sensor (TES) detectors designed to provide spatially-resolved high-resolution spectroscopy. The onboard reconstruction software provides energy, spatial location and arrival time of incoming X-ray photons hitting the detector. A new processing algorithm based on a truncation of the classical optimal filter and called 0-padding, has been recently proposed aiming to reduce the computational cost without compromising energy resolution. Initial tests with simple synthetic data displayed promising results. This study explores the slightly better performance of the 0-padding filter and assess its final application to real data. The goal is to examine the larger sensitivity to instrumental conditions that was previously observed during the analysis of the simulations. This 0-padding technique is thoroughly tested using more realistic simulations and real data acquired from NASA and NIST laboratories employing X-IFU-like TES detectors. Different fitting methods are applied to the data, and a comparative analysis is performed to assess the energy resolution values obtained from these fittings. The 0-padding filter achieves energy resolutions as good as those obtained with standard filters, even with those of larger lengths, across different line complexes and instrumental conditions. This method proves to be useful for energy reconstruction of X-ray photons detected by the TES detectors provided proper corrections for baseline drift and jitter effects are applied. The finding is highly promising especially for onboard processing, offering efficiency in computational resources and facilitating the analysis of sources with higher count rates at high resolution.

Residual Strain Predictions for a Powder Bed Fusion Inconel 625 Single Cantilever Part

The laser powder bed fusion (LPBF) process involves using a laser beam to selectively melt metal powder with a desired shape on a substrate to create a part layer-by-layer. As an Additive Manufacturing (AM) process, laser powder bed fusion (commonly referred to as selective laser melting—SLM) offers superior design freedom over conventional manufacturing methods and enables the production of complex, lightweight geometries with applications in the aerospace, automotive, and biomedical industries. In addition to enhanced design freedom, AM technologies provide improved material utilization and allow for reduced assembly needs. However, the reliability and repeatability of additively manufactured parts is a challenge to the wide-scale adoption of the technology for safety critical parts. A critical limitation of process optimization is the prediction and control of residual stresses, distortion, and microstructure evolution. This work focuses on the development and implementation of a numerical modeling technique for the prediction of residual strains within an Inconel 625 LPBF part. The model, using the SIMULIA Additive Manufacturing Scenario App, based on the Abaqus 2018 finite element solver, was developed and analyzed as part of a submission for the NIST AM Benchmark 2018. A sequentially coupled thermo-mechanical analysis was adopted to replicate the building conditions of a single cantilever beam built at the NIST laboratories. The results of the blind study were compared to X-ray diffraction (XRD) measurements of the physical build. The predicted three-dimensional residual strain field showed a high level of accuracy and the submission described in this paper received joint first prize in the residual elastic strain category of the NIST AM Benchmark 2018. The results presented in this paper reflect only findings before the benchmark measurements were posted on the NIST website.

Extended analysis of six-times ionized barium (Ba VII)

The seventh spectrum of barium (Ba VII) has been investigated using experimental recordings made on a 3-m normal incidence vacuum spectrograph in Canada in the wavelength region 300–2000Å. The data below 350Å was supplemented from the spectrograms recorded on a 10.7-m grazing incidence spectrograph of NIST laboratory USA. The sources used to excite the spectra in both the cases were triggered spark. Previously reported levels of 5s25p2, 5s5p3, 5s25p5d and 5s25p6s in Ba VII have been confirmed except the 1P1 level of 5s25p5d. The analysis has been extended considerably to include new configurations 5s25p6d and 5s25p7s in odd parity configuration and doubly excited configurations 5s25p6p, 5s25p4f, 5s25p5f, 5p4, 5s5p25d and 5s5p26s in even parity configuration. The 3F4 level of 5s25p5d configuration has now been established through the identification of transitions from 5s25p6p. In all, one hundred twenty-two levels have been established in this spectrum out of which ninety-two are new. A configuration interaction Hartree–Fock calculation supports the analysis.

Special report: Budget boosts physical sciences in FY 2008, most other research down

For the second year, President Bush's American Competitiveness Initiative would significantly increase funding for research at NSF, Department of Energy, and NIST laboratories. Other agencies aren't so lucky.

Requirements for the Development of Bacillus Anthracis Spore Reference Materials Used to Test Detection Systems.

Bacillus anthracis spores have been used as biological weapons and the possibility of their further use requires surveillance systems that can accurately and reliably detect their presence in the environment. These systems must collect samples from a variety of matrices, process the samples, and detect the spores. The processing of the sample may include removal of inhibitors, concentration of the target, and extraction of the target in a form suitable for detection. Suitable reference materials will allow the testing of each of these steps to determine the sensitivity and specificity of the detection systems. The development of uniform and well-characterized reference materials will allow the comparison of different devices and technologies as well as assure the continued performance of detection systems. This paper discusses the special requirements of reference materials for Bacillus anthracis spores that could be used for testing detection systems. The detection of Bacillus anthracis spores is based on recognition of specific characteristics (markers) on either the spore surface or in the nucleic acids (DNA). We have reviewed the specific markers and their relevance to characterization of reference materials. We have also included the approach for the characterization of candidate reference materials that we are developing at the NIST laboratories. Additional applications of spore reference materials would include testing sporicidal treatments, techniques for sampling the environment, and remediation of spore-contaminated environments.

GAINS AND LOSSES MARK 2007 BUDGET

As PROMISED IN HIS STATE of the Union Address, Presi- dent George W. Bush has proposed significant increases in his fiscal 2007 budget for several agencies that fund physical science research. These increases, however, are matched by budget cuts in R&D spending at other agencies. In general, the science bud- gets this year are flat except for increases in selected high-priority agencies, said John H. Marburger III, science adviser to the Presi- dent and director of the Office of Science & Technology Policy, at a briefing. The increases are part of the President's American Competitiveness Initiative. Among the selected agencies getting increases are NSF, most National Institute for Standards & Technology programs, and the Department of Energy. NSF would receive an 8% boost to $6.0 billion, its largest increase in many years, including a 6% rise in mathematics and physical science research spending to $1.2 billion. NIST's laboratory programs are slated for a ...

Revised and Extended Analysis of Six Times Ionized Xenon: Xe VII

The spectra of xenon were recorded in the 100–1250 Å region on a variety of vacuum spectrographs at the Antigonish, NIST and Troitsk laboratories. The source used at the Antigonish and the NIST laboratories was a xenon-gas-puff low inductance vacuum spark while at the Troitsk laboratory it was a 40 kV fast capillary discharge. On the basis of our new measurements the earlier analysis of the 5s5p, 5p2, 5s5d, 5s6s (J = 1), 4d95s25p (J = 1) and 4d95s24f configurations of Xe VII by Kaufman and Sugar [J. Opt. Soc. Am. 84, 1919 (1987)] was confirmed except for the 5s5d 1D2 level. Three of the five levels of Xe VII reported by Larsson et al. [Physica Scripta 51, 69 (1995)] were accepted and their absolute level values revised. Out of the twelve levels of the 5p5d configuration published by Cavalcanti et al. [J. Opt. Soc. Am. B 14, 2459 (1997)] only one level was found to be correct. In addition to the missing 5p2 1So level, we have established 37 new levels belonging to the 5s(4f + 5f), 5p4f, 5s6p, 5p5d and 5p6s configurations. Ninety-two lines are now classified in the Xe VII spectrum out of which sixty lines are new. Least-squares-fitting (LSF) and Hartree–Fock (HF) calculations were carried out to interpret the level structure of the Xe VII spectrum.

Seventh Spectrum of Lanthanum: La VII

The spectra of lanthanum ions were photographed in the90Å–1220Å region on a 3-m normal incidencespectrograph at the Antigonish laboratory and a 10.7m grazingincidence spectrograph at the NIST laboratory. The source used in bothlaboratories was a triggered spark. The5s25p3–(5s5p4+5s25p25d+5s25p26s)transitions of La VII were analysed. All five levels of the groundstate and 37 of 44 levels of the5s5p4+5s25p25d+5s25p26sconfigurations have been established. 102 lines have been classifiedin the 307–1005Å region. Hartree–Fock (HFR) andLeast-Squares-Fit (LSF) calculations were carried out to interpret thespectrum.

House Science Committee Acts on NIST Laboratories

Committees in both chambers of Congress are considering bills to dismantle the Department of Commerce, including the National Oceanic and Atmospheric Administration. The main bill in the House, HR 1756, sponsored by Rep. Dick Chrysler (R‐Mich.), has been referred to 11 different committees, each of which has jurisdiction over some part of it. In September, the House Science Committee, chaired by Robert Walker (R‐Pa.), held a hearing on the proposal and marked up the portions of Chrysler's bill relating to science and technology.In addition to abolishing the Commerce Department, Chrysler's bill would mandate selling NIST's laboratories and those of NOAA's Office of Oceanic and Atmospheric Research “to a private sector entity intending to perform substantially the same functions as were performed by the laboratories.” It also would terminate NIST's Advanced Technology Program (ATP) and Manufacturing Extension Partnership (MEP).

Analysis of the 4d9 −4d8 (4f + 6p) transition array of Sn VI

The spectrum of tin was photographed in the 150-250 Å region on a 10.7 m spectrograph at the NIST Laboratory in Gaithersburg, USA, and the 3 m spectrograph in Troitsk, Russia, using a triggered spark source. In the 4d9 −4d8 (4f + 6p) transition array of Sn VI spectrum 85 lines have been classified. Sixty-three levels belonging to the 4d84f and 4d86p configurations have been established. Parametric least-squares-fitting calculations including configuration interaction between the 4d8(5p + 6p + 4f + 5f + 6f) and 4p54d10 configurations were carried out to interpret the observed spectrum adequately.

Using NASREM for real-time sensory interactive robot control

SUMMARYThe Flight Telerobotic Servicer (FTS) is a robotic device which will be used to build and maintain Space Station Freedom. The FTS is expected to evolve from its initial capability of teleoperation toward greater autonomy by taking advantage of advances in technology as they become available. In order to support this evolution, NASA has chosen the NASA/NIST Standard Reference model for Telerobot Control System Architecture (NASREM) as the FTS functional architecture. As a result of the definition of generic interfaces in NASREM, the system can be modified without major impact. Consequently, different approaches to solve a problem can be tested easily. This paper describes the implementation of NASREM in the NIST laboratory. The approach is to build a flexible testbed to enhance research in robot control, computer vision, and related areas. To illustrate the real-time aspects of the implementation, a sensory interactive motion control experiment will be described.

Analysis of the 4d7 and 4d65p configuration of the ninth spectrum of antimony: Sb IX

The spectrum of antimony was photographed in the 120 Å-270 Å on a 3-m grazing incidence spectrograph at the Moscow laboratory and 10.7 m grazing incidence spectrograph at the NIST laboratory in Washington. A triggered spark source was used in both laboratories to excite the Sb IX spectrum. Seventeen of 19 levels of the 4d7 configuration and 132 of 180 levels in the 4d65p configuration of the Sb IX have been established. Two hundred and seventy three lines have been classified as the 4d7-4d65p transitions in the 167 Å-202 Å region. Least-squares-fitting calculations were carried out which interpret the spectrum quite adequately.