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Radioactivity Group

Welcome

The Radioactivity Group develops and improves the metrological techniques used for the standardization of radionuclides, and carries out a wide range of programs in low-level standards for environmental measurements and monitoring, standards for nuclear medicine, standards and testing criteria for radiological instrumentation used for security, and radionuclide metrology. Its mission is to develop, maintain, and disseminate radioactivity standards, develop and apply radioactivity measurement techniques, and engage in research to meet the requirements for new standards. Our participation in international comparison exercises has kept us abreast of efforts of other laboratories and helped us to maintain our own capabilities. 

We continue to lead the national effort, in collaboration with the Department of Homeland Security, to develop standards and protocols for radiation instrumentation for early and emergency responders. We have developed an accreditation program with NVLAP for instrument testing. We are also spearheading the development of ANSI standards and testing protocols for spectroscopic portal monitors, neutron detectors, x-ray and high energy gamma-ray interrogation methods, x-ray imaging, data formats for instrumentation data output, and training standards for responders. 

The Group continues to lead an internationally-recognized program for standards in nuclear medicine, providing the national standards for radionuclides used in 13 million diagnostic procedures and 200,000 therapeutic nuclear medicine procedures annually in the US. Primary standards of two radionuclides, 223Ra and 68Ge have been developed. A new initiative, aimed at establishing standards and measurement support to improve accuracy and consistency in quantitative Positron Emission Tomography/X-ray Computed Tomography (PET/CT) and Single-Photon Emission Computed Tomography (SPECT) imaging, is well underway. 

The Group's environmental program leads to community in low-level and natural matrix material measurements and standardization, and continues to be heavily involved in the world-wide measurement of environmental-level radionuclide dispersal and contamination through a large number of international intercomparisons and traceability programs and SRMs. A Radioanalytical Emergency Procedures Manual Database has been developed to assist organizations preparing for emergency response. 

Revitalization of our basic metrology capabilities has involved extensive work in many areas. In addition to introducing the TDCR method to routine use at NIST, work is also progressing on the construction of second-generation TDCR system. The principle method of primary standardization at NIST is live-timed 4πβγ anticoincidence counting. During the past two years, NIST researchers have adapted this method to perform primary measurements on a variety of radionuclides. A new automated ionization chamber has been developed at NIST to measure up to 100 samples with programmable sample queuing, sample handling and measurement parameters.

Programs/Projects

ICE 62755 Standard N42 Data Format—The purpose of the IEC 62755 standard N42 data format is to facilitate manufacturer-independent transfer of information from radiation measurement instruments used for detection of illicit …

Active Interrogation Standards—Active interrogation involves directing nuclear radiation into a closed container and measuring secondary radiations to gain information about the contents of the container.

Testing of Radiation Detection Systems—NIST is working together with the Department of Homeland Security (DHS) Domestic Nuclear Detection Office (DNDO) in testing radiation detection equipment for homeland security applications. 

Standardization of Am-243—A new standard solution of 243Am, an important radionuclide for the US and international environmental-measurements communities, was developed and disseminated at NIST as SRM 4332E.

New Standardization of Ra-228—Measurements of radium isotopes in the naturally-occurring radioactive decay chains (i.e., 235U, 238U, and 232Th) are exceedingly important for various applications related to geochemical studies.  

Blind Measurement Comparisons of the USA and UK Pb-210 National Standards—The National Institute of Standards and Technology (NIST), Radioactivity Group, and the National Physical Laboratory (NPL) of the UK, and the national metrology laboratories of their respective …

International Comparison of Pu-241—All of the plutonium isotopes, which have a very high biotoxicity, are man-made and result from various nuclear activities. Plutonium-241 is a very low-energy beta emitter with Eß(max) = (20.8 ± …

Technetium-99m Primary Standardization and International Comparison—Technetium-99m (99mTc) is used in two-thirds of all diagnostic nuclear medicine procedures in the United States.

New Statistical Analysis Tools—Members of the Radioactivity Group (RG) have been actively collaborating with statisticians in the NIST Statistical Engineering Division to identify new tools that would be of assistance in …

Radon Binding to Water-Soluble Cryptophane—Collaboration on investigating the thermodynamics of radon binding with a new and novel class of cryptophane molecules is currently underway with researchers from the University of Pennsylvania …

Components of Variance in Liquid Scintillation Counting—As part of the standardization of the 239Pu solution that was disseminated by NIST as Standard Reference Material (SRM) 4330C, a detailed study was performed to better understand and ascertain how …

Primary Radioactivity Standardization of Ni-63—Ni-63 is of considerable interest and importance in radionuclidic metrology as well as for radiation protection surveillance around nuclear facilities.

Quantification of the Alpha Wall Effect in Liquid Scintillation Counting—A long-standing uncertainty in liquid scintillation (LS) counting has been the possible loss of counting efficiency.

International Comparison of Tc-99—An international measurement comparison for a 99Tc solution hosted by National Physical Laboratory (NPL) of the UK, (CCRI(II)K-2.99Tc comparison) was completed.

Radioactivity Standard Reference Material Program—The Standard Reference Materials Program of the National Institute of Standards and Technology (NIST) provides science, industry, and government with a central source of well-characterized …

ANSI/IEEE N42.42 Standard—The purpose of the N42 data format is to facilitate manufacturer-independent transfer of information from radiation measurement instruments for use in homeland security applications as well as for …

National Technical Nuclear Forensics CRMs—The U.S. Department of Homeland Security (DHS) is committed to using cutting-edge technologies and scientific talent in its quest to make America safer.  

NIST Laboratory for Quantitative PET-CT Imaging—As part of a NIST-wide effort to develop a metrological infrastructure for quantitative medical imaging, the Radioactivity Group established a dedicated facility to support its efforts to develop …

Automated Multi-Sample Ionization Chamber for Radioactivity Standards—Precise calibration of short-lived radioactive material is essential for nuclear medicine and power plant applications. Scientists in the NIST Radioactivity Group have developed an automated …

Primary Standardization of Radionuclides by Anticoincidence Counting—The standardization of radionuclides by primary methods is the foundation for all the standards and services provided by the NIST radioactivity group.

Development of Epoxy Based Ge-68 Standard Phantom Sources—The use of imaging data for staging of disease, treatment planning, and monitoring of patient response continues to increase. In these types of studies, where comparability between successive scans …

Calibration of Epoxy Based Ba-133 Standard Phantom Sources for Use in an International Comparison for Quantitative SPECT—The International Atomic Energy Agency (IAEA) recently initiated a Cooperative Research Project (CRP) entitled “Development of Quantitative Nuclear Medicine Imaging for Patient Specific Dosimetry” …

Calibrations of Large-Volume, Solid Ge-68 Phantom Sources for Monitoring PET Scanner Performance in Clinical Trials—The interpretation of quantitative imaging data obtained from Positron Emission Tomography (PET) studies requires an understanding of the measurement variability due to instrumental effects, …

Micelle Effects in Liquid Scintillation Counting—Liquid scintillation counting (LSC) techniques underlie many of the primary activity measurements at NIST and other national metrology institutes. The microscopic properties of LSC samples affect …

Standards for Clinical Radionuclide Calibrators—NIST maintains a collection of dose calibrators and develops and reports on secondary activity standards for imaging and therapeutic nuclides.

FPGA-based Triple-to-Double Coincidence Ratio Liquid Scintillation Counting—The triple-to-double coincidence ratio (TDCR) method of liquid scintillation counting employs three detectors to facilitate the experimental determination of counting efficiencies so that activity …

Test and Evaluation Protocols for ANSI/IEEE N42 Standards—The purpose of these test and evaluation protocols is to provide additional information to the published ANSI/IEEE N42 series for homeland security applications for radiation detection systems.

Standards Development for Detection of Illicit Trafficking of Radioactive—The National Institute of Standard and Technology (NIST) is working in the development of ANSI/IEEE and IEC standards for the detection of illicit trafficking of radioactive materials for homeland …

Gamma-ray Spectrometry System—NIST is equipped with a high resolution gamma-ray spectrometry system used for activity and impurity measurements of gamma-ray emitting sources used for nuclear power plants, medical and homeland …

Highlights

For the Radioactivity Group

 
Contact

Unterweger 

Michael Unterweger, Group Leader

301-975-5536 Telephone
301-975-5530 Group Secretary
301-926-7416 Facsimile

100 Bureau Drive, M/S 8462
Gaithersburg, MD 20899-8462

Radioactivity Staff Directory