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Projects/Programs

Topic Area
Displaying 126 - 150 of 1618

Basic Metrology: Dose/Dose-Rate Effects in Alanine Dosimetry

Ongoing
Check standards are used by the NIST Radiation Physics Division to monitor the performance of the alanine dosimetry system which is central to its high-dose transfer dosimetry service. These measurements are performed to confirm the operational readiness of the calibration curve. Deviations from the

Basic Metrology: High-Dose Dosimetry Uncertainty Tables

Ongoing
Gammacell™ Calibration Geometry Dose Rate Uncertainty Source Type A (%) Type B (%) Water Calorimetry in Vertical Beam 0.16 0.51 Gammacell/Pool Source Ratio Data 0.10 Pool/B036 Source Ratio Data 0.17 Geometry Correction Factor 0.11 Field Uniformity 0.01 Source Timer (irrad time > 8min) 0.20 Co-60
X-ray Spectroscopy

Basic Metrology: High-Resolution X-Ray Spectroscopy

Ongoing
X-ray sources of interest include Electron Beam Ion Trap (EBIT), Electron Cyclotron Resonance Ion Source (ECRIS), and laser-produced plasma ion sources, including the new generation of petawatt lasers. In support of these efforts, we also maintain laboratory x-ray sources from 1 keV to 300 keV
hydrogen angular distribution graph

Basic Metrology: Neutron Cross Section Standards

Ongoing
Data from a number of NIST collaborations have produced measurements for the standards program. Measurements are underway now at NIST of the 6Li(n,t) and 235U(n,f) cross sections at sub-thermal energy. These will be the first absolute measurements of these cross sections in this energy region. These
ampoules

Basic Metrology: NIST-3 Standard Ampoules and Automatic Tip Sealing

Ongoing
Report NISTIR 8254 referenced above was intended to document and archive the historical record for the acquisition and testing of standardized ampoules used by the NIST / NBS Radioactivity Group since the 1950s. These ampoules were intended to contain 5 mL of solutions of radionuclides decaying with
Monte-Carlo simulation

Basic Metrology: Primary Standards for Radionuclides

Ongoing
As the National Metrology Institute (NMI) for the US, NIST is responsible for realizing the SI units. The derived SI unit for activity of a radionuclide is the becquerel, Bq. NIST has a proud history of contributing to the development of new and improved primary standardization methods for the Bq to

Basic Metrology: Recent Primary SRM Standardizations

Ongoing
SRM No. Radionuclide Reference Date Method Used Relative expanded uncertainty ( k = 2) References 4332f Americium-243 8 March 2024 The certified massic activity for 243Am was obtained by 4pab LS spectrometry with two commercial LS counters. The beta detection efficiencies for the 243Am daughter were
Remote Sensing

Basic Metrology: Remote Sensing Methods for Imaging Dose to Water

Ongoing
Ultrasound and laser interferometry, widely used for nondestructive testing and remote sensing applications, are being used here to measure dose distributions in irradiated water phantoms by taking advantage of temperature dependence in the speed of sound and optical index of refraction of water
photon attenuation cross section measurements

Basic Metrology: Standard Reference Data on Radiation Interactions

Ongoing
This work continues in the Division's Photon and Charged-Particle Data Center. The compilations of the Data Center rely heavily on evaluating measurements and on their synthesis with available theory to extend the data and provide for comprehensive coverage over broad ranges of energy and materials

Bayesian Metrology Project

Ongoing
Research, develop, and apply Bayesian methods to the metrological problems of NIST; promulgate results to other metrology laboratories and to NIST customers. Four specific areas are targeted: traceability, interlaboratory comparisons, calibration, and part inspection. These areas were chosen because
NIST engineer Kate Remley led development of new 94 gigahertz calibrated signal source and 16-antenna array operating at 83 gigahertz

5G & Beyond

Ongoing
The realization of this long-term vision requires tackling key technical challenges to allow for greater temporal, spectral, coding and spatial resource efficiency. As well, these technologies all rely on high levels of electronic device integration, yielding a radical new connectorless measurement
BIB-trap detector

BIB-trap detector

Ongoing
Limitations of Standard BIB Detectors Currently available BIB detectors exhibit excellent detectivity, but are limited in their use for spectral calibrations by detection inefficiency and spectral response inhomogeneity. The maximum quantum efficiency of these doped silicon devices is near 60%
absolute cryogenic radiometer

Bilateral Comparison of Spectral Responsivity in the Vacuum-Ultraviolet

Completed
The last decade has seen numerous key comparisons in the field of photometry and radiometry between different national metrology institutes (NMIs) in the context of the Mutual Recognition Arrangement. At first, these comparisons were restricted to wavelengths longer than 200 nm, with just the
Microfluidic tissue/organ on a chip system

Bioelectronic Sensors for Tissue/Organ-on-a-Chip Systems

Ongoing
We apply our expertise in micro/nanofabrication, electrokinetics and cell-based assays to develop bioelectronic sensors in microfluidic platforms. We are working on a platform that entraps cells for electrochemical monitoring in an environment that has mechanical properties more similar to those
Optical coherence tomography

Biofabrication of Tissue Engineered Constructs

Ongoing
OCT imaging was assessed using a model scaffold-cell system consisting of a polysaccharide-based hydrogel seeded with human Jurkat cells. Four test systems were used: hydrogel seeded with live cells, hydrogel seeded with heat-shocked or fixed dead cells and hydrogel without any cells. Time series
Streptococcus mutans

Biofilm Models to Evaluate Structure-Function Relationships

Ongoing
Biofilms are complex 3D microbial structures that exist throughout nature including on our skin and gut mucosa, in waterways, and in soil. They are typically composed of multiple microbial species surrounded by proteins, polysaccharides, and extracellular DNA woven together into a hydrated matrix

Biogenic Modeling and Measurements

Ongoing
For purposes of top-down GHG emissions monitoring, a high-resolution biospheric model is needed that can resolve fine-scale variability in the atmosphere due to biospheric fluxes. Therefore, we currently focus on models that resolve the diurnal cycle and can be run at high spatial resolutions (e.g

Bioimaging

Completed
Imaging and image analysis are used ubiquitously in biological and biomedical research. One of the great advantages of imaging is its intuitive information content; much can be learned from just a glance at the data. On the other hand, these data generally contain a very large amount of untapped
Bioman lifecycle

Biomanufacturing Initiative

Ongoing
The objective of the NIST biomanufacturing program is to support US biopharmaceutical industry delivery of high quality and low cost protein drugs around the world. The mission is fulfilled through the development of standards, measurement science, and state of the art tools that support advances in

Biomaterials for Oral Health

Completed
NIST along with its partners has a long commitment to scientific excellence with demonstrated impact in improving the oral health of the public. NIST researchers are leaders in this field and create a community by engaging other researchers, industry, and regulatory agencies to address urgent needs

Biometric Compression Information

Ongoing
Friction Ridge Compression On February 24, 2014 we proudly announced the release of the final version of this guidance! You can download the final version of the guidance here: NIST Special Publication 500-289 Final (02/24/2014) More recently, on April 7, 2016, we're proud to announce the release of

Biometric Quality

Ongoing
Quality analysis is a technical challenge because it is most helpful when the measures reflect the performance sensitivities of one or more target biometric matchers. NIST addressed this problem in August 2004 when it issued the NIST Fingerprint Image Quality algorithm, which was designed to be