Just adopted by the Department of Homeland Security (DHS), four new national standards* establish baseline performance criteria and testing requirements for radiation-detection devices. The specifications will ensure that ever more widely used detectors will reliably discern above-background levels of radiation at seaports, airports, border crossings, and other key spots. Covering devices ranging from pocket-sized alarms to shipping-container-sized portal monitors, the standards are the products of a yearlong collaboration of diverse government and private-sector organizations, led by the National Institute of Standards and Technology (NIST) in cooperation with the Institute of Electrical and Electronics Engineers (IEEE).

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The extraordinary partnership included, among others, the U.S. Postal Service, private shipping and delivery firms, detector manufacturers, defense agencies, the U.S. Coast Guard, the Transportation Security Administration, and Department of Energy laboratories. The standards-development work was initiated and funded under a multi-year program that NIST manages for DHS’s Science and Technology Directorate. From start to finish, the standards were developed—and approved—in near-record time, about a third of three years typical for standards of this type.

Published as IEEE standards, the four also have been approved by the American National Standards Institute (ANSI), administrator and coordinator of the U.S. private-sector voluntary standardization system. IEEE is responsible for updating the standards as radiation-detection technology evolves.

For DHS purposes, the standards provide clear guidance for state and local officials as they evaluate options for purchases of radiological and nuclear detection equipment. The specifications are a necessary step toward ensuring that customs agents, first responders, and other homeland security personnel will be equipped with the best available technology to alert them to the presence of radioactive materials, such as those that can be used to construct “dirty” bombs.

These guidelines also will assist manufacturers by providing performance standards and test methods, as well as minimum characteristics for four classes of radiation detection equipment covered by the standards.

NIST’s Technical Contributions

In addition to its lead role in organizing the necessary expertise and drafting the new standards, NIST has provided critical testing and measurement capabilities required to assess whether detectors perform up to specifications. To supply this technical infrastructure, the Institute’s Physics Laboratory, the Nation’s ultimate source for accurate measurements of X-rays, gamma rays, neutrons and other forms of ionizing radiation, expanded its test bed for evaluating hand-held radiological detectors and truck portal monitors, used to inspect truck- and ship-borne freight.

NIST physicists also installed portal monitors at NIST entry points to evaluate incoming traffic under real-life conditions. With the resulting data, they determined how environmental factors influence the detectors’ effectiveness. In addition, NIST has developed safe, durable sources of radiation-emitting materials, as called for in the new standards, to calibrate detectors and to verify the accuracy of their radiation measurements. These “check” sources also will be used in training on how to evaluate detector technology for compliance with the standards.

NIST is now completing development of test and evaluation procedures that can be used to determine whether radiation detectors meet the ANSI standards’ technical requirements, the basis for a product-certification system. These procedures will be analyzed both at NIST and Department of Energy Laboratories. Results and recommendations will be furnished to DHS for its use in setting up a program for certifying detectors that comply with the standards’ specifications.

^* The four DHS-adopted standards for radiation and nuclear detection equipment are: ANSI N42.32: Performance Criteria for Alarming Personal Radiation Detectors for Homeland Security; ANSI N42.33: Radiation Detection Instrumentation for Homeland Security; ANSI N42.34: Performance Criteria for Hand-Held Instruments for the Detection and Identification of Radionuclides; and ANSI N42.35: Evaluation and Performance of Radiation Detection Portal Monitors for Use in Homeland Security.

Date created: 03/01/04
Last updated: 03/29/04
Contact: inquiries@nist.gov