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Physical Measurement Laboratory / Radiation Physics Division

Dosimetry Group

Projects/Programs

Displaying 1 - 25 of 34

Accelerator Facilities

Ongoing
The Division's accelerator facilities continue to support a broad range of research efforts in the areas of industrial and medical dosimetry, homeland security, radiation-hardness testing and materials-effects studies. Topics of research during this reporting period included: (1) a broad-energy
spectrometer images

Basic Metrology: Applications of Diagnostic X-ray Spectrometers

Ongoing
These have been fielded to help characterize the performance and x-ray spectra from advanced medical x-ray sources, laser-produced plasmas, terawatt pulsed accelerators, electron cyclotron resonance ion sources, electron-beam ion traps, intense ultrafast laser sources, and inverse-Compton

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
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

Calibration Services: High-Dose Dosimetry

Ongoing
NIST developed the alanine dosimetry system in the early 1990's to replace radiochromic dye film dosimeters. Later in the decade the alanine system was firmly established as a transfer service for high-dose radiation dosimetry and an integral part of the internal calibration scheme supporting these
WAFAC system

Calibration Services: Low-Energy Photon Brachytherapy Sources

Ongoing
Since 1999, over 1,500 seeds of more than 40 different designs from 18 manufacturers have been calibrated using the WAFAC. On-site characterization at seed manufacturing plants for quality control, as well as at therapy clinics for treatment planning, relies on well-ionization chamber measurements

Calibration Services: New Calibration Facility for X-Ray Air Kerma

Ongoing
The NIST x-ray calibration facility is composed of a suite of rooms that includes the 11 m by 7 m calibration range, a dedicated equipment room, connected by custom shielding ports for communication with the x-ray tubes in the radiation area, an operator control center with a viewing window and

Comparison: Co-60 Absorbed Dose for High-Dose Dosimetry

Completed
The NIST comparison demonstrated the need to know the participant's calibration scheme and dose rates, as well as the inclusion of an additional dose level (1 kGy, in addition to 5 kGy, 15 kGy, and 30 kGy). The rationale for modifying the protocol was based on the recent NIST characterization of a
X-ray Security-Screening

Documentary Standards: X-ray Security Screening Applications

Ongoing
This work fills well-documented gaps in transportation security, which have been highlighted in Executive and Legislative requirements for 100 % screening of baggage, cargo, and airline passengers. This is accomplished through a corpus of new standards, test methods, test artifacts, dosimetry
solar cells

Electron-Beam Irradiation of Solar Cells

Ongoing
NIST irradiates solar cells that are manufactured by leading developers of high-efficiency solar photovoltaic cells for space applications. As part of the space-qualification process, the performance of these cells in a space environment must be validated. This validation process includes the
X-ray Imaging

Industrial: Enhanced X-Ray Imaging

Ongoing
A variety of in-house x-ray sources and detector technologies invite efforts to optimize traditional image quality metrics and the use of algorithms and methods to extract the maximum amount of information available. These results are used to inform x-ray standards development and will drive the
Alanine/EPR

Medical (Archive): Small-field Therapy Dosimetry Studies Using Alanine/EPR

Completed
Developments in radiotherapy have significantly increased the use of small fields in stereotactic procedures and IMRT fields composed of small fields. Ionization chambers are not always suitable where situations of high dose gradients, time-dose variance, and non-uniform beam distributions are